Polyesters - Science topic

The idea of recycling post-consumer PET into valuable products, like aryl polyesters with properties similar to aryl polyamides (e.g., Kevlar and Nomex), is an interesting one. However, the proposed method involves several complex reactions that would need to be evaluated for their technical feasibility, economic practicality, and the final material properties. Let's break down the steps and consider the viability:

1. Hydrogenating PET with Copper Chromate to Obtain 1,4 Benzenedimethanol Ethylene Glycol Ether

Hydrogenating PET (polyethylene terephthalate) in the presence of copper chromate at 3000 psi is theoretically possible, but it would require careful consideration of the reaction conditions. Hydrogenation reactions typically require high pressure and temperature, and the role of copper chromate is to act as a catalyst for the hydrogenation process. However, this approach might be problematic for the following reasons:

Catalyst Selection: Copper chromate is a strong oxidizing agent, and it may not be the most ideal catalyst for this reaction, especially for selective hydrogenation. More commonly, palladium or platinum-based catalysts are used in hydrogenation reactions. Copper chromate could lead to unwanted side reactions or degradation of the PET, potentially reducing the yield of the desired product.

Reaction Conditions: The high pressure (3000 psi) and temperature would need to be optimized. While it's possible to hydrogenate aromatic compounds, the conditions may lead to undesirable polymer degradation or decomposition.

Selectivity and Yield: If the hydrogenation is successful, the goal is to obtain 1,4 benzenedimethanol ethylene glycol ether (a bisphenol ether), which would be a challenging synthesis in this context. Ensuring high selectivity and yield of this specific product would be critical, but hydrogenation could also lead to over-hydrogenation or other side products.

2. Cleaving the 1,4 Benzenedimethanol Ethylene Glycol Ether by Acid Hydrolysis to Obtain 1,4 Benzenedimethanol

The second step involves cleaving the 1,4 benzenedimethanol ethylene glycol ether through acid hydrolysis. This is a plausible reaction, as ether bonds can be cleaved under acidic conditions. The challenge here would be the reaction efficiency and the potential degradation of the resulting product, 1,4 benzenedimethanol, which could be sensitive to the reaction conditions (strong acids, high temperatures).

Hydrolysis Conditions: Mildly acidic conditions (e.g., dilute sulfuric acid or hydrochloric acid) might work, but care must be taken to avoid over-hydrolysis or degradation of the monomer. The yield of 1,4 benzenedimethanol would depend on factors such as temperature, acid concentration, and reaction time.

Purification: After hydrolysis, purification steps would be necessary to isolate the 1,4 benzenedimethanol, as the reaction may yield a mixture of products.

3. Reacting 1,4 Benzenedimethanol with Terephthalic Acid to Produce an Aryl Polyester

The third step is the polymerization of 1,4 benzenedimethanol with terephthalic acid to produce an aryl polyester. This step is similar to the synthesis of polyesters like PET or other high-performance thermoplastics. The reaction between 1,4 benzenedimethanol (a diol) and terephthalic acid (a dicarboxylic acid) would proceed via esterification to form the polymer.

Polymerization Conditions: The reaction would require high temperatures and a catalyst (such as titanium-based catalysts) to promote esterification and remove water. The molecular weight of the polymer would depend on the reaction conditions, and the polymerization process would need to be carefully controlled to avoid incomplete polymerization or low molecular weight chains.

Material Properties: The resulting polyester could have good mechanical properties, such as strength and rigidity, but it may not inherently possess the same thermal stability and strength as aryl polyamides like Kevlar or Nomex. Polyesters, particularly those based on terephthalic acid, are generally not as thermally stable as aryl polyamides. Aryl polyamides (e.g., Kevlar) possess unique strength and heat resistance due to the strong hydrogen bonding between aromatic rings and the rigid, high-strength polymer backbone.

However, modifying the polymer with certain additives or co-monomers might improve its thermal stability and mechanical properties, though it is unlikely to match the exceptional strength and heat resistance of Kevlar or Nomex unless specific modifications are made to the polymer structure (e.g., incorporating additional aromatic groups or rigid linkages).

Economic and Practical Considerations

Economic Viability: Recycling PET in this manner could be economically viable if the process can be optimized to maximize yield and minimize costs. The high pressure (3000 psi) and temperature required for the hydrogenation step could make the process energy-intensive. Additionally, the need for specialized catalysts and the potential for side reactions would add to the cost. If the process is scaled up, the costs of hydrogenation, hydrolysis, and polymerization could be significant.

Post-consumer PET Recycling: PET is a widely recycled polymer, but converting it into high-performance materials like aryl polyamides or specialized polyesters could open up new avenues for recycling. However, this would depend on the efficiency of the conversion process and the market demand for such materials.

Environmental Impact: If this process can be done efficiently, it could help reduce PET waste, contributing to more sustainable recycling practices. However, the environmental impact of using potentially hazardous chemicals (e.g., copper chromate, acids) and the energy required for high-pressure reactions would need to be evaluated.

Conclusion

While the general steps you propose (hydrogenation, hydrolysis, and polymerization) are chemically plausible, there are significant challenges to making the process economically viable and producing a material with properties comparable to aryl polyamides like Kevlar and Nomex. Specifically:

The hydrogenation step could face selectivity issues, and the use of copper chromate as a catalyst might not be ideal.

The hydrolysis step is feasible but would require precise control to avoid side reactions.

The polyester produced would likely have good mechanical properties but would need modifications (e.g., higher aromatic content or co-monomers) to achieve the extreme strength and thermal stability of aryl polyamides.

Ultimately, the concept could be developed into a valuable recycling process, but the properties of the resulting aryl polyester would likely not match the strength and thermal stability of Kevlar or Nomex without further refinement of the polymer chemistry. The economic feasibility would depend heavily on optimizing reaction conditions and minimizing energy and catalyst costs.

Dear Md Toufiqur Rahman, chromatography and fractionation techniques. My Regards

Dear Riswat Musbau, you can use precipitation via the solvent/nonsolvent of couple, chloroform/methanol, as it is done in the attached file. My Regards

Dear Md Toufiqur Rahman, to consider is water content and temperature scanning rate. The lowering of melting temperature most probably is due to the plasticizing effect of water. So, better to do repeated scan and take the result of the repeated cycles. Repeated scan dry the sample from water. My Regards

High temp. Need to dye polyester. And it is heated fast in warm condition. Perspiration is very low.

You can try to etch the thread untreated and processed in alkali. Then it will be clear if there is a chemical reaction.

Effects of plasma treatment on biodegradation of natural and synthetic fibers

npj Materials Degradation volume 8, Article number: 23 (2024) Cite this article

Abstract This study investigates the application of plasma treatment as a means to enhance biodegradation and modify the structural characteristics of fibrous composites. The methodological component of the study includes the selection of the research object; production of composites; low-temperature plasma treatment, and treatment of biodegradability and mechanical strength of samples. The strengthening of fibers with cellulose leads to a significant improvement in mechanical strength. Such an indicator as mechanical strength increases from 18 to 21 MPa. Treatment of natural fibers with low-temperature plasma led to an increase in mechanical strength from 18 to 25 MPa. Treating reinforced fibers with low-temperature plasma currently results in an even greater enhancement in mechanical strength, increasing from 18 to 29 MPa.The electron microscopy of samples reveals some differences in cell wall microfibrils between plasma-treated and non-treated samples. The non-treated fibres are found to have chips and voids. Meantime, the plasma-treated fibres show structural changes in certain regions which resemble wood charring. Through a comprehensive analysis, this research underscores the substantial impact of plasma treatment on the degradation kinetics and morphological features of cellulose-based composites. The results reveal distinct alterations in the composition and behavior of plasma-treated fibres, signifying a shift towards enhanced biodegradability. The natural fibres examined in this study contained 28–30% lignin, whereas the composites exhibited a lower lignin content of 21–23%. These findings corroborate the inference that plasma treatment induces significant changes in fibre structure, accelerating the biodegradation process by 7 days.

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Introduction The lightweight materials industry is a strategically important sector of the economy in many countries. Due to the growing population, the demand for clothing, footwear, and other textile products increases each year. At the same time, lightweight materials industry products must meet strict requirements related to hygiene, durability, and performance properties such as adhesion, water resistance, and so forth. Compliance and product quality largely depend on the methods and technologies used to manufacture and process natural and synthetic materials1,2.The textile industry makes use of both natural and synthetic materials. Man-made fibers are used to create non-woven and artificial materials or impart specific properties to those materials. Synthetic fibers are superior to some products and inferior to others; hence, the choice of synthetics may be justified. However, polymeric materials do not decompose easily, and represent a serious threat to the environment in countries with intense production. According to recent reports, nearly 30% of polymer waste is subjected to incineration, some 30% is recycled, and the remaining 30% is left undisposed3,4,5.Scholars are actively engaged in the advancement of synthetic polymers designed for degradation by bacteria and other microorganisms within the natural ecological milieu6,7,8. These polymers can be useful in many industries, including packaging, the textile industry, medical equipment, the automotive industry, and so forth9,10,11,12. Recent studies have also investigated the use of plasma for processing synthetic polymers to increase their biodegradation. Plasma treatment can change the surface structure of the polymer, thereby providing a more efficient decomposition of the synthetic material by biological processes13,14,15.The study of biodegradation of synthetic polymers exhibits certain gaps. Unexplored areas encompass the pathways of biodegradation for various polymer types, factors influencing biodegradation, resultant products, and biodegradation methods16. Some researchers posit that successful biodegradation of the synthetic component within a natural-synthetic blend occurs when the natural polymer is chemically attached (grafted) to the synthetic polymer. Bacterial activity initiates the degradation of the natural polymer chain, which subsequently extends into the synthetic segment17,18,19.The work20 uses epoxy as a matrix material, and polymer composites with reinforcement from untreated and alkali-treated Zanthoxylum acanthopodium bark fibers (5–25 wt.%). Hand lay-up was used in the development of the epoxy composites. The mechanical characteristics and water absorption rates of the produced epoxy composites were evaluated following ASTM standards. Epoxy composites containing 20 wt.% of alkali-treated Zanthoxylum acanthopodium bark fibers had excellent mechanical qualities, including an ultimate tensile strength of 47.3 MPa, according to the test findings. However, there was a positive correlation between fiber loading and water absorption. The fiber bonding and void characteristics of the analyzed composites were observed using a scanning electron microscope.In the work21, Vachellia farnesiana fibers were selected and extracted by the manual retting process. The obtained Vachellia farnesiana fibers were chemically treated with hydrochloric acid (HCl) and sodium hydroxide (NaOH) solutions. The chemically treated and untreated Vachellia farnesiana fibers were characterized for physical, chemical, tensile, morphological, and thermal properties. Test results showed that the cellulose content was 47.8 ± 0.697 wt % for NaOH-treated Vachellia farnesiana fibers with reduced moisture and amorphous contents. HCl-treated Vachellia farnesiana fiber showed more cellulose content removal, which resulted in the degradation of its properties due to the acidic nature of HCl.Plasma treatment is recognized as a dry and clean process. The utilization of low-pressure cold plasma for the pre-treatment of natural fibers is becoming increasingly prevalent as a method for surface modification22. This approach offers advantages compared to traditional chemical treatment, as it does not require water or chemicals, rendering it environmentally friendly and cost-effective. Plasma modification substantially reduces the number of chemical pollutants. It etches the fiber surface, enhancing the action of the binding agent for improved adhesion23. It can also render the surface rough through material ablation, enhancing adhesion. Moreover, it introduces free radicals and can alter the chemical structure. Low-pressure cold plasma modifies the fiber surface without changing the material volume. Additionally, it eliminates the need for chemical solvents and reduces process time24.Existing studies lack a comprehensive examination of the biodegradability of plasma-modified fibers. This article investigates the influence of low-temperature plasma treatment on the biodegradation of cellulose and its composite. The results provide insights into assessing the biodegradability of other materials. The study underscores the potential of plasma treatment in enhancing the quality of natural and synthetic fibers. Low-temperature plasma treatment of cellulose-based materials is employed for this purpose.Most studies note that low-temperature plasma treatment is a progressive and rather effective method since it can change the chemical composition of the fiber surface and the physical structure of molecules while maintaining the bulk material properties. Utilizing low-temperature and low-pressure plasma treatment demands a lesser amount of gasoline when contrasted with alternative techniques, leading to a near-total mitigation of waste generation. However, there are limited data on the biodegradability of plasma-treated fibers. The empirical evidence that fiber materials can partially or completely decompose after plasma treatment and that it affects the rate of biodegradation can serve as justification for the use of plasma treatment with a wider range of natural and synthetic fibers.This study aims to measure the biodegradability of plasma-treated wood fiber-reinforced polypropylene composites to determine whether plasma modification alters the rate of biodegradation. The secondary objectives of the study are (1) to examine the low molecular weight components of wood fiber-reinforced polypropylene composites during biodegradation, and (2) to explore the composition and properties of substances isolated from the plasma-treated samples. Finally, the study attempts to experimentally substantiate the mechanism behind the plasma-induced decomposition of cellulose.

Results and discussion Mechanical strength of fibers The results of determining the mechanical strength of the obtained fibers are given in Table 1.Table 1 Results of mechanical testing.Full size tableAnalyzing the data presented, we can conclude that strengthening fibers with cellulose leads to a significant improvement in mechanical strength. In particular, such an indicator as mechanical strength increased from 18 to 21 MPa, or by 16.7%. Treatment of natural fibers with low-temperature plasma led to an increase in mechanical strength from 18 to 25 MPa, or by 33.3%. Treatment of reinforced fibers with low-temperature plasma led to an even greater increase in mechanical strength, from 18 to 29 MPa or by 50%.The electron microscopy of cellulose samples revealed some differences in cell wall microfibrils between plasma-treated and non-treated samples (Fig. 1). The non-treated fibers were found to have chips and voids. Meantime, the plasma-treated fibers show structural changes in certain regions that resemble wood charring.Fig. 1: Microscopic examinations of cellulose.📷a, c No plasma treatment. b, d Plasma treatment.Full size imageInterestingly, following plasma treatment, certain segments of the cellulose fiber exhibited a hollowed morphology. In contrast, the control sample displayed increased fragility due to the presence of voids and ruptures in the cell walls. This implies that plasma treatment influenced the microfibril structure of cellulose. Typically, reinforcing elements of microfibrils were diminished as a result of plasma treatment, enhancing flexibility and disrupting structural integrity.When investigating the composite of polypropylene fibers reinforced with cellulose (Fig. 2), a distinct behavior was observed following plasma treatment. The fibers of the treated composite exhibited fewer visible defects and were predominantly embedded within the polypropylene matrix. Importantly, no slip lines or voids were evident on the fracture surface. Instead, the images displayed polymer adhesion to the fibers at multiple points, indicating a noteworthy transformation of material composition and interactions.Fig. 2: The surface morphology of cellulose-reinforced polypropylene.📷A, C No plasma treatment. B, D Plasma treatment.Full size imageHigh interfacial shear strength and, consequently, a stronger interaction between fibers and matrices can significantly decelerate the biodegradation of composite materials. Plasma changes the structure of cellulose, with the latter completely dissolved in a solution of sodium hydroxide and simply in water. Low molecular weight components occur during depolymerization. Nearly 50 products were generated through the plasma-chemical decomposition of fibers; some (19%) are listed in Table 2. By comparing the quantitative composition of components in the table, significant differences between the degradation products of plasma-treated and untreated fibers can be identified. Specifically, several compounds exhibit changes in molecular mass and percentage yield as a result of plasma treatment. For instance, compounds such as C6H10O5, 3-deoxyglucofuranose, and C6H6O3 display altered molecular masses and percentage yields following plasma treatment, indicating the influence of plasma on the degradation process. These variations underscore that plasma treatment affects the molecular structure, which, in turn, may impact the biodegradation of composites.Table 2 Products resulting from the biodegradation of plasma-treated and non-treated fibers.Full size tableThe yield of levoglucosan (C6H10O5) was 7.92%, suggesting the achievement of stability after plasma treatment. A rather large amount (10.1%) of 3-dioxyglucosenone is released with a molecular weight of 144 g·mol−1 during cellulose dehydration. The concentration of methyl maltol is lower (6.12%) but its molar mass is almost the same as that of 3-dioxyglucosenone. Two substances with the same molar mass of 126 g·mol−1, pyrogallol and anhydrosucrose, account for 4.56 and 20.1% of the yield, respectively. A furan aldehyde called furforol (C5H6O2) is released in the amount of 5.11%; part of furfural can be released with the participation of xylane. All molecules with a mass below 90 Da are marked as decay products of O2 and CO2.Plasma does not affect sulfate lignin. The plasma-treated natural fibers were 21% lignin, whereas the composites had a lignin content of 18%. The study results show that the dehydration and decomposition velocities of non-composites are almost 2 times lower as compared to composites. In natural conditions, lignin is strongly influenced by filamentous fungi, which have the power to cause the degradation of complex polymers by enzymes; in these conditions, materials decompose faster.Judging by data concerning the degradation products of plasma-treated fibers, the chemical processes associated with the biodegradation of natural cellulose are similar to those occurring in untreated samples. The structural changes to microfibrils, however, caused the biodegradation time of plasma-treated cellulose to accelerate.In the case of plasma-treated specimens, biodegradation commenced on the 12th day of the experiment, while for untreated specimens, it occurred a week later, specifically after 19 days. The buried plasma-treated material changed and became brittle and thinner than the control. At the end of the 30-day biodegradation test, prominent changes were detected in the samples.The biodegradation of natural fiber-reinforced composites can occur through a variety of mechanisms; the choice depends on the type of natural filler used, its quality, and its chemical composition. The plasma-treated cellulose-reinforced polypropylene composites exhibit clear signs of decomposition. This finding coincides with previous research. It also suggests that plasma-treated fiber materials can decompose, partially or completely, and that plasma treatment can alter the rate of biodegradation.Plasma modification of the fiber surface is one of the most elaborated methods for improving the quality characteristics of materials. Plasma treatment can affect the surface properties of materials, such as the ability to bond dissimilar fibers. The adhesion of materials is often used to metalize, paint, or glue surfaces to obtain composites. This method also makes it possible to develop a range of properties less typical for unprocessed natural fabrics, such as hydrophilicity, dirt and dust repellency, antistatic properties, and so forth. In addition, plasma removes fat and other organics from fur and wool. It improves the absorption of dye pigments25,26.The essence of the plasma treatment method is to treat a material with a plasma medium (ionized gas) at low or atmospheric pressure. This causes surface reactions and modifications up to a change in the functional groups of molecules and a change in surface energy. Plasma is an ionized gas, in which free electrons and ions coexist. Plasma is produced by heating a gas to extremely high temperatures or by subjecting it to strong electromagnetic fields. Both of these processes may result in the release of electrons from atoms and molecules. The electrons have enough kinetic energy to remove additional electrons in case of a collision with other molecules27. These collisions induce cascade ionization. A release of ions and electrons occurs, balanced by the recombination of material molecules until plasma reaches equilibrium.The results obtained by Hamad28 show that plasma treatment of keratin-containing materials, such as wool and fur, at reduced pressure, opens the fiber cuticle, caused by the mutual repulsion of multiple charged jets. This allows the effective removal of organic compounds from the Merino wool fibers, without changing the fiber structure and physical properties29,30. Zille31 evaluated the effects of plasma surface treatment of flax, cotton, and animal-based fibers (wool, pile) on the tensile load resistance. Plasma treatment activates the surface of various synthetic materials, such as ultra-high modulus polyethylene, thereby improving their ability to absorb or completely repel moisture. This occurs due to the increase in surface tension of the fibers immersed in various gaseous media13,15,17.It is worth mentioning that some scientists31,32,33,34 agree that plasma treatment reduces the total energy consumption associated with the production of synthetic fibers by 25% as compared to other treatment methods. Research demonstrates that the modification of natural fibers requires 14–50% less energy than the production of synthetic fibers. The real value in this broad range depends on a myriad of plant growth factors and plasma processing parameters.This study aligns with previous research emphasizing the significance of incorporating environmentally degradable components into composite materials35. Earlier investigations examined fiber degradation alongside polylactic acid and clay silicates, revealing that the quantity and nature of natural constituents influence composite biodegradation35. Correspondingly, analogous burial-based studies36,37,38 echo our findings, showcasing the accelerated degradation of triple compositions compared to double ones due to increased biodegradable content. Moreover, experts in plasma treatment advocate its efficacy in preserving textile properties and enhancing mechanical attributes of biodegradable composites, considering it more sustainable than chemical methods39,40,41,42,43.The choice between plasma and chemical treatment hinges on material requisites41,42,43. Plasma treatment surpasses chemical counterparts in efficacy, transforming material surfaces, enhancing adhesion, and durability44,45,46. This approach is particularly useful for biodegrading recalcitrant materials by promoting microbial interaction47,48,49. Similarly, studies focusing on fiber-modified bioplastics suggest enhanced fiber-matrix adhesion41,42. Cold plasma emerges as an efficient, eco-friendly alternative40,41,42,43, fostering sustainable composite markets.This holistic exploration of plasma-treated materials showcases their potential in renewable and biodegradable materials research47,50,51. Industrial use of plasma-modified materials necessitates eco-conscious biodegradability. Consequently, leveraging natural fibers for polymer matrix composites aligns with environmental awareness and promotes renewable resources35,52,53. Such studies aid in curbing waste and toxic releases, ensuring safer decompositions and material cycles. This research contributes to reducing environmental impact while bolstering sustainable material applications.The study utilized scanning electron microscopy (SEM) to show that plasma treatment significantly affects both the biodegradation process and the material’s structure. SEM enabled a comprehensive examination of the process phases, particularly focusing on the interaction between electrons and the specimen. The study’s methodology involved selecting the research subject, creating composites, applying low-temperature plasma treatment, and assessing the biodegradability and mechanical strength of the samples. The addition of cellulose fibers leads to a significant improvement in mechanical strength. More precisely, the measure of mechanical strength increased from 18 to 21 MPa, indicating a growth of 16.7%. The utilization of low-temperature plasma on natural fibers led to a significant 33.3% improvement in mechanical strength, elevating it from 18 to 25 MPa. The mechanical strength of reinforced fibers was significantly enhanced with low-temperature plasma treatment, resulting in a rise from 18 to 29 MPa, or a 50% improvement. The electron microscopy study revealed notable differences in cell wall microfibrils between the samples that underwent plasma treatment and those that did not. Unprocessed fibers exhibited the presence of chips and cavities. Concurrently, the fibers that have been subjected to plasma treatment display distinct changes in their structure in certain regions, like the charring process observed in wood. The cellulose cell walls of both treated and untreated samples exhibited disparities in the microfibrils, including alterations in structure after plasma treatment. In addition, changes were noted in composites composed of polypropylene fiber and cellulose. The fibers that received plasma treatment exhibited enhanced integration, as shown by the absence of slip lines on the fracture surface. The quantitative measurement table of biodegradation products reveals significant differences in composition between the treated and untreated fibers. These alterations illustrate the influence of plasma on chemical processes and biodegradation. Plasma treatment can accelerate the biodegradation process and modify the characteristics of materials. This can generate composites that possess enhanced durability and resilience, a crucial factor in the manufacturing of ecologically friendly products and the effective utilization of waste.

Methods The flowchart of the experimental part is shown in Fig. 3.Fig. 3📷The flow-chart of the experimental part.Full size imageThe production of wood fiber-reinforced polypropylene composites This study addresses natural fibers of the finest coniferous wood species and cellulose-containing materials as experimental objects. Those were unbleached softwood sulfate pulp and softwood sulfate lignin. The sample of natural wood fibers was analyzed using a scanning electron microscope. The SEM analysis method included the following steps: sample preparation, sample loading, vacuum chamber, and electron beam directed at the sample. The latter interacted with the sample, causing electron emission from the sample surface. Electron detection: a detector located in the SEM chamber identified electrons emitted by the sample. These signals were then processed and used to create an image of the sample’s surface topography and morphology.The results demonstrated that the average length of wood fibers was 190 µm (range, 100–400 µm; standard deviation: 63 µm) and that the average width was 50 µm (range, 20–100 µm; standard deviation: 19 µm).Table 3 shows the approximate composition of fiber samples54.Table 3 The approximate composition of fiber samples.Full size tableThe production of polypropylene/cellulose composites requires using a solid-state shear pulverization. The sheared polymer method helped to reduce the particle size of cellulose materials. The cellulose fibers were mixed with a polypropylene matrix in a plastic mixer (Haake Rheocord 9000, Germany) with a rotor velocity of 60 rpm at 185 °C for 8 min. The resulting blend underwent compression molding at 185 °C at a pressure of 10 MPa for 15 min. Before being used, the samples rested at room temperature for 5 days.Figure 4 shows the scheme of the reactor.Fig. 4📷The reactor’s scheme.Full size imageThe plasma reactor consists of a solenoid or radio-frequency induction coil (A) wound around a borosilicate glass tube (B). There will be a supply of gas (C) in the vacuum, and a vacuum pump valve (D) will keep the gas inside. The induction coil is to store energy within a magnetic field, which is numerically equal to that produced by the source to induce a current in the winding, generating a magnetic field of the solenoid. Inside the external glass tube, there is a partially open glass tube (E). It contains fibers that a stepper motor rotates (F) throughout the entire plasma treatment process.Low-pressure and low-power plasma does not cause excessive surface heating, and the glass tube is warm to the touch. Therefore, there is no excessive thermal exposure, thermal degradation of the fibers, or their incineration to be expected.The parameters of low-temperature plasma are as follows: I = 4.8–5.2 mA; U = 25–28 kW; gas medium: sulfur hexafluoride (SF6); additional medium – water (Н2О); exposure time = 10−30 min; Р = 102 Pa.The plasma treatment procedure is described below 1) The glass tube and the sample holder are cleaned with an air gun and disinfected with isopropyl alcohol to eliminate any contamination of the vacuum and plasma. All individuals involved in the experiment are required to wear nitrile gloves to prevent contamination.2) A 5-g sample of investigated fibers is weighed and placed on the sample holder (internal glass tube (E) as shown in Fig. 2). The tube is inserted into the reactor and attached to the axis of the stepper motor for further rotation of the sample.3) Once the reactor is closed, the air is evacuated by a vacuum pump. The pump must be connected to the reactor through a chamber equipped with a diaphragm valve. The latter opens slowly at the evacuation starts to prevent fibers from being absorbed in.4) As soon as the pressure falls below 10 Pa (10−1 mbar), the stepper motor rotates, causing the sample holder to rotate and the fibers to mix. A short-term increase in pressure occurs due to the release of accumulated gas.5) The selected process gas (partially or fully ionized; without signs of being polymerized) is introduced into the chamber using a needle valve or mass flow controller. During pumping, the pressure increases to almost 102 Pa (1 mbar) for 2 min, and then the gas supply is over. The procedure is repeated after 2–5 min of further pumping. This ensures a faster decrease in pressure as moisture transport occurs and guarantees enough gas in the tube.6) Finally, the system is pumped down to an atmospheric pressure of about 10−1 Pa (10−3 mbar). Because fluorocarbon bonds are sensitive to X-ray, the following sequence was followed: initial phase: 250–350 eV; final phase: 0-1,150 eV; high-resolution oxygen spectrum, binding energy: 526–540 eV.The equipment used here includes a gas chromatograph СhroZen UHPLC, a gas chromatograph-mass spectrometer GCMSQP2010 Plus, a thermal desorber TD-20, an ATR-8200HA attachment (Pike Tech), a scanning electron microscope (SEM) Sigma VP ZEISS, and a probe microscope MultiMode 8. The chemical analysis was compliant with GOST55. Results were analyzed by gas chromatography using gas chromatograph Agilent 7820.Mechanical testing Tensile testing (ISO 527) was carried out using a universal testing machine (UTM) with a gauge length of 6 cm and a speed of 5 mm/min. All the mechanical results were obtained with an average of 10 samples.Biodegradability testing The biodegradability test assessed the resulting cellulose composite’s ability to decompose under the influence of microorganisms within certain environmental conditions. The samples were buried in the soil for 30 days. This method is widely used for assessing the ability to decompose since it provides a simulated environment similar to natural decomposition.During testing, the samples were buried to a depth of 10–15 cm and covered with soil. The monitoring of soil humidity and temperature ensured that they remained within a certain range for microbial activity (25–75% and 15–25 °C, respectively). After 30 days, samples were excavated from the soil and analyzed for the presence and amount of material residues. The degradation degree was then identified by measuring mass loss.Statistics analysis Statistical analysis was performed using a One-way Analysis of Variance, with significance reported at p ≤ 0.05. All findings were presented as means ± standard deviations of at least five experiments.

Data availability All materials were developed by the authors. All data are presented in the article.

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Author information Authors and Affiliations Department of Textile Industry Technology and Materials Science, M.Kh. Dulaty Taraz Regional University, Taraz, KazakhstanMarzhan Nyssanbek Department of Physics, Kazan National Research Technological University, Kazan, Russian FederationNatalya Kuzina Department of Building Materials and Technologies, Russian University of Transport, Moscow, Russian FederationValery Kondrashchenko Scientific Research Institute Natural and Technical Sciences, South Kazakhstan University named after M. Auezova, Shymkent, KazakhstanAbdugani AzimovContributions Marzhan Nyssanbek – Conceptualization, Methodology, Validation; Natalya Kuzina –Investigation, Project Administration, Software, Supervision; Valery Kondrashchenko – Formal Analysis, Data Curation, Resources, Writing – Review & Editing; Abdugani Azimov –Funding Acquisition, Resources, Visualization, Writing – Original Draft Preparation.Corresponding author Correspondence to Abdugani Azimov.

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About this article 📷Cite this article Nyssanbek, M., Kuzina, N., Kondrashchenko, V. et al. Effects of plasma treatment on biodegradation of natural and synthetic fibers. npj Mater Degrad 8, 23 (2024). https://doi.org/10.1038/s41529-024-00437-xDownload citation Received09 October 2023 Accepted18 January 2024 Published01 March 2024 DOIhttps://doi.org/10.1038/s41529-024-00437-xShare this article Anyone you share the following link with will be able to read this content:

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Dear Adzrie Baharudin,

Nondestructive testing methods can effectively validate self-healing properties of construction materials, aiding future research on self-healing properties. Raman spectroscopy offers promising non-destructive in situ characterization of self-healing materials, particularly polymers and biopolymers, to better understand their chemical mechanisms and improve their reliability and safety in various applications. Therefore, Self-healing phenomena on the micro- and nanoscale can be confirmed through characterization methods, such as scanning electron microscopy, to confirm the release of healing agents from nanofibers, spread, react, and solidify. Self-healing polymers can be characterized using various techniques, including visual, spectroscopic, scattering, and dynamic methods, to understand their molecular mechanisms and future trends.

With best wishes

Dear Suganth,

The composite products are designed generally to work in the strain range of 0.1% to 0.3%. Hence the young's modulus is the difference in stress in the 0.1% to 0.3% strain range divided by 0.002 strain.

What are the fibre and the matrix in your composite specimen?

Consider AATCC TM 20 (Fiber Analysis: Qualitative) or TM20A (Fiber Analysis: Quantitative).

Nelson Houser

Gelatin-HEC spheres containing ascorbic acid are susceptible to degradation and may lose their effectiveness over time. Here are some tips to prolong their lifespan:

1. Store them in a cool, dry place away from direct sunlight. Humidity and heat can accelerate the degradation of the spheres.

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4. Check the expiration date on the sphere packaging. Use them before the expiration date to ensure they are still effective.

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6. If possible, avoid mixing the spheres with other active ingredients. This can cause chemical reactions that can alter the quality and lifespan of the spheres.

By following these tips, you can extend the life of your gelatin-HEC spheres containing ascorbic acid. However, it is important to note that even with proper care, the lifespan of the spheres can be limited, so be sure to regularly check their quality and effectiveness.

Thank you very much . Could you please inform me an example

The question is not clear. Ethanol 2x represents that its concentration is 2times more.

Dear Sachin Sudhakarrao Aughad

Regarding non-halogenated FR, usually silicon or phosphorous are the best choices. I am not quite sure as potassium. Nevertheless, it will depend on the form these elements are incorporated. FR can be incorporated to the resins either physically (imagine fillers, or particles, or fibers) or chemically (imagine the elements in the molecular structure, for example as functional groups, such as silanes, siloxanes, etc). It is preferred when the elements are chemically bonded, but this is harder to accomplish. What I am telling you with this? That if your potassium is in the form of salts or particles, it may be suitable for flame retardancy. Tests should be obviously performed. I know that Mg(OH)2 nanoparticles have a good effect on flame retardancy, so why not potassium, right?

The book Fire Retardancy of Polymeric Materials (A. Grand and C. Wilke) can help you with further info.

Hope it helps!

Dear Karol Tutek, usually NMR and FTIR are the tools to estimate both grafting degree/density and length. My Regards

https://doi.org/10.1002/(SICI)1097-4628(19991209)74:11<2616::AID-APP8>3.0.CO;2-H

Thank you Vadym Chibrikov for your suggestions i will surely look into it .

Dear Sibel Duman, you can use foaming agents. My Regards

Dear Foroogh Khodadadi, better will be to follow a standard procedure such the ASTM one :

Please have a look at the following document. My Regards

Yes, but some may polycondense via methylolation with formaldehyde, but the hydroxyl groups remain unchanged, such as phenol and pyrogallol (3 OH groups by ring).

For the second part I have never Seen a case on that. My Regards

Dear Mehmet Kösem, the best methods are those named real-time monitoring reaction progress, mainly gas chromatography and infrared spectroscopy. An old method is the iodometry which quantify the amount C=C. Details are presented in polymerization textbooks. My Regards

Dear Joanna J. Sokołowska, please have a look at the following books. My Regards

- Chemical Resistance of Thermoplastics, William Woishnis, Sina Ebnesajjad (2011)

- Chemical Resistance of Specialty Thermoplastics, William Woishnis, Sina Ebnesajjad (2012)

- Chemical Resistance of Engineering Thermoplastics, Erwin Baur, Katja Ruhrberg, William Woishnis (2016)

- Chemical Resistance of Commodity Thermoplastics, Erwin Baur, Katja Ruhrberg, William Woishnis (2016)

Dear all, is it a crystalline polymer ? If so, it is expected that solvent casting leads to highly crystallized samples compared to melt processing. My Regards

The main impacts are the increase in melting and glass transition temperature.

Most likely you have a side reaction that generates conjugation that is not accounted for in the planned reaction, and/or oxidized species. Just increased molecular weight won't do it. You may cut down on oxidized species by working under N2 (if you're not doing it already), while taking into account that this may have some effect on polymerization kinetics (for radical polymerization). Otherwise, just try to think up all the nightmare side reactions that are plausible in your case...

Ali Naderi Beni I recommend you to go through the following theoretical studies.

These works would give you clues about what you want to know.

-

-

-

Thank you Mr. Brain Lee!

actually, I wanted to know about any additive or masterbatches that can be used to soften polyester rather than denier change or spinning process.

You may think of simple absorption tests.

To control the uptake of dye you may have to run tests using different compositions of the composite and optimise the composition for the best .

Dear Ghaidaa,

This link is also interesting:

Best,

Fran

FTIR would be a good solution. Acrylic fibers have peaks at 2240 cm-1 and 1740 cm-1 due to nitrile and ester groups which do not exist in the cotton FTIR.

Check https://medicine.yale.edu/keck/ycga/Images/TRIZOLRNAIsolation_092107_tcm240-21453.pdf

I am having a similar issue with RPMI2650. The passage is relatively low and I am using polystyrene plates 0.4um pore size. Besides, the blank inset is giving extremely high and increasing TEER values

Adhesives have the main function of creating a bond of the polymers to various substrates;

the characteristics of the polymer carrying the OH group depend on the monomer and in turns, will determine the final Tg, mfft, tack, dry-time, crosslink density and so on.

choose the monomers accordingly

I think the solution lies in optimizing the operating/processing conditions. When the components are highly reactive, prepolymers are the best choice. Mold release agents may also solve the pealing off. Best of Luck

Molecular modeling of cellulose in amorphous state. Part I: ...

Put simply, heat and water might hydrolyze some polyester, and during wear test, if use have used that resin as "glue" of your composite, more resin and embedded nanoparticles would come off, that ius, wear rate would rise, unless water increasing bonding between functionalized surface of nanoparticles and the polymeric matrix. not all polyesters are equally prone to hydrolysis, though. In general, due to steric effect and resonance stabilizations, aromatic acid-based esters might do better than aliphatic ones.

Dear Dr. Thitiwut Srichalongrat ,

perhaps it would be possible to make a resistance measurement with a simple digital tester, keeping one tip on a conductive part and moving the other by placing it on the parts to be investigated ....

Simple but it could work.

My best regards, Pierluigi Traverso.

Dr. Barot,

You can try Tall oil based dimer acids.

Also try incorporating plasticizers for enhanced results.

Dear all, you can use less active curing system, for exemple a peroxide with higher decomposition temperature. My Regards

Dear Sumit Bhowmick, I don't think it has a link with whether addition or step-growth polymerizations, especially for polyesters and polyamides, as these laters may be obtained by both modes of polymerization. Fatigue is a matter of chain architecture and demensions, it is a function of the chemistry and the physical properties, and the stress type, conditions and intensity. All this contribute to the relaxation behavior of a given polymer. My Regards

Check this out:

Thank you

Hello Ashu,

Maybe these papers help you:

Methods of interconversion between linear viscoelastic material functions. Part I—A numerical method based on Prony series

Viscoelastic relaxation modulus characterization using Prony series

Dear Angela Vanegas, I don't think it will be possible to find a universal paint for such an application. Environmental stresses are different from country/continent to anothers. Please have a look at the following RG document. My Regards

Dear 子敬 楊強

The literature that may be useful are;

Dear all, in addition to Prof. Frank T. Edelmann proposed documents, please have a look to the following RG free document and the attached free download internet files. My Regards

Dear Michele, this seems to be a significant practical problem. As an inorganic chemist I'm clearly not a proven specialist in they area. Possible solutions to this problem seem to be hidden in the patent literature. Nevertheless, it might be worth having a look at the following potentially useful links which could help you in your analysis:

DIGITALLY PRINTING WITH UV LED CURED INKS ON POLYCARBONATE

(see attached pdf file)

Relevant papetnts:

(also attached)

I hope this helps. Good luck with your work and best wshes, Frank Edelmann

Dear Mansour Hachemi, bioressources based polymers have many outstanding properties inattainable by synthetic polymers, mainly the biodegradability and biocompatibility. In terms of properties they are progressively improved via many processes such as blending and crosslinking (low degrees), to be competitive with traditional synthetic polymers. May be the economic aspect is the last obstacle for their widespread production and uses. My Regards

If you haven't try Collagen permeable membrane, it is worth trying.

Dear Gabrielle Ilha

You may find the following articles

I am also recently working o the oxidation mechanism of PE. You can look through this ASTM standard for better understanding the FTIR peaks of PE especially for oxidation.

ASTM F2102

Dear James Morgan, if you are thinking so just for the sake to get rid of the residual unreacted monomer, you can choose more simple and efficient way. Dialysis seems to be the more suited option. My Regards

One general difference is that polyesters typically are thermoplastics; that is they can be melted, reformed, and reused. Epoxies typically are thermosets, meaning they are crosslinked and once cured do not easily melt, but will tend to char.

If your part is not too expensive, you could cut off a piece of it and try to melt it.

Most polyesters, like soda bottles or polyester fabrics will melt on a hotplate or stove top on a sheet of aluminum foil.

Of course, if the parts are available commercially, the manufacturer should state the materials from which the part is made.

I think you are dealing with a case of a ghost line. Have you tried blocking the membrane? It looks to me that in the lines, the proteins are acting as a blocking agent, that's why you have the white lines and the purple background. It also appers to me that something is messing up with your conjugate-line interaction, maybe the MetOH? Maybe you could try removing the MetOH from your antobodies. Also, you could try with less conjugate, or try first with liquid conjugate with an OD around 5.

Someone already asked a similar question, check it out here https://www.researchgate.net/post/what_caused_the_ghost_test_line_on_lateral_flow_assay

Good luck!

if the quantity is enough you can use an extruding process to release the bubble from the polymer

Research some MPIF publications.

Dear Dohyeong Kim, this is due to the differences in reactivity of the different carboxylic acids in each compound. This leads to high chain lengths (high MW and high viscosity) for the most reactive and low chain lengths for the least reactive one. Please check the attached file. My Regards

جيد

Dear Chiang Ching-hua, yes OH groups on TiO2 surface react with NCO ones, it is a well investigated method for surface modification. Just do a Google search, exemple is attached. My Regards

For measuring viscoelastic properties kindly cheak our following paperBio-Chemical Composition, Functional and Rheological Properties of Fresh Meat from Fish, Squid and Shrimp: A Comparative Study

March 2017International Journal of Food Properties 20(68)

DOI: 10.1080/10942912.2017.1308955

Dear João P. M. Pereira, in the following free access documents, acetone and other solvents are used. My Regards

Dear Dr. Manjunath Shettar ,

I suggest you to have a look at the following papers:

- Effect of Orientation of Glass Fiber on Mechanical Properties of GRP Composites

MUHAMMAD IRFAN ,FARZANA HABIB ,KHURAM KHALID ,SHAHZAD ALAM ,WAQAS IQBAL , AND KHURAM KHALID

J.Chem.Soc.Pak., VOL. 32, 3, 265 (2010)

Available at: https://jcsp.org.pk/ArticleUpload/88-346-1-RV.pdf

- Flexural Strength of Glass and Polyethylene Fiber Combined with Three Different Composites

F. Sharafeddin, A A Alavi, and Z Talei

J Dent (Shiraz), 14(1): 13–19 (2013)

Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3927662/

- Effect of fiber volume fraction on the mechanical properties of randomly oriented glass fiber reinforced polyurethane elastomer with crosshead speeds

E.Elkazaz, W.A.Crosby, A.M.Ollick, M.Elhadary

Alexandria Engineering Journal, Vol. 59, Issue 1, Pages 209-216 (2019)

Available at: https://www.sciencedirect.com/science/article/pii/S1110016819301656

and, on RG, at: https://www.researchgate.net/publication/338135494_Effect_of_fiber_volume_fraction_on_the_mechanical_properties_of_randomly_oriented_glass_fiber_reinforced_polyurethane_elastomer_with_crosshead_speeds

Best regards, Pierluigi Traverso.

Can you kindly elaborate on your answer Mr. A M Fadl

Dear

Adipate polyesters ( Poly(ethylene adipate)& poly(butylene adipate) can be solved in THF(Tetrahydrofuran) at 25 °C.

Dear Michał Wrzecionek, I attached interesting documents plus the following RG discussion on the same subject. What I want you to consider since you are using glycérol, you are dealing with a branches and not a liear polyester. Operating GPC is totaly different for both cases, so be carefull in selecting the operating parameters before running it. My Regards

Dear Dr. Akanksha Pragya ,

I suggest you to have a look at the following, interesting papers:

-Processing of plasma-modified and polymer- grafted hydrophilic PET surfaces, and study of their aging and bioadhesive properties

Maria Jesus Pérez-Roldán, Dominique Debarnot, Fabienne Poncin

RSC Advances 4(56):31409 (2014)

Available on RG at: https://www.researchgate.net/publication/265382750_Processing_of_plasma-modified_and_polymer-_grafted_hydrophilic_PET_surfaces_and_study_of_their_aging_and_bioadhesive_properties

-Plasma Processing for Tailoring the Surface Properties of Polymers (Chapter)

Hisham M. Abourayana and Denis P. Dowling

Surface Energy, Book ISBN: 978-953-51-2216-6 (2015)

Chapter available at: https://www.intechopen.com/books/surface-energy/plasma-processing-for-tailoring-the-surface-properties-of-polymers

-Surface Properties of PET Polymer Treated by Plasma Immersion Techniques for Food Packaging

Péricles Lopes Sant’Ana, José Roberto R. Bortoleto, Nilson C da Cruz, Elidiane C Rangel, Steven F. Durrant, Laura Moreira Costa Botti, Carlos Alberto Rodrigues Anjos, Sofia Azevedo, Carine Isabel, Vasco Teixeira, Eber Antonio Alves Medeiros, Nilda de Fátima F Soares

International Journal of Nano Research, Vol. 1 (2018)

Available at: https://innovationinfo.org/articles/IJNR/IJNR-1-106.pdf

Best regards, Pierluigi Traverso

We are working on the same concept using primary RPE cells. I was able to achieve reasonable success with Millicell 0.45 um 12 mm cell culture inserts. Since the membranes are detached following the cryosections we conducted our stainings on the membrane before embedding it into OCT and sectioning. While signals are significantly diminished by freezing the strong targets are still viable. In order to distinguish between the cells and the membrane deposition of i.e. lipids, we used Calcein AM live to stain. Another approach with reasonable success was using z-stack on the cell monolayer and observation of the orthogonal projection. We are also interested in preserving the good morphology of the RPE cells on the membranes but so far we were only able to investigate depositions of the RPE cells to the membrane and not a good cross-section morphology of the RPE cells. Johnson et al use vibratome on non-embedded membranes https://www.pnas.org/content/108/45/18277 I'm thinking of using laser cutter on non-embedded membranes since vibratome is not available for us.

The molecules of UHMWPE are longer than those of high-density polyethylene (HDPE) due to a synthesis process based on metallocene catalysts which result in UHMWPE molecules typically having 100000-250000 monomer units per molecule. While, compared to HDPE's there are only 700-1800 monomers.

According to the chemical structure, degree of crystallinity, and melting temperature of UHMWPE, it has some properties that make it unique such as low stretch, high strength, low density (0.93 g/cm3), high abrasion resistance, high resistance to wear and impact, resistant to concentrated acids, alkalis, and organic solvents, extremely low moisture absorption and a very low coefficient of friction.

It is necessary to mention that except mechanical and chemical properties, the process-ability of polymers is the main parameter of industrial scale production.

First of all fabric quality and Pr-treatment are most important.? Is it mercerized or half bleach? crease problem or lining are mostly due to poor Pr-treatment. As reactive dye is a soluble dye.

Secondly, if the process is exhaust within bath? than fabric needed to be stirred continuously.

Dear Dr. Ritesh R Bhat,

in general, the effect of seawater immersion on the durability of glass- and carbon-fibre reinforced polymer composites, when immersed in seawater at a temperature of 30 °C, up to 2 years of exposure have also been studied. The composites experienced significant moisture absorption and suffered chemical degradation of the resin matrix and fibre/matrix interphase region. This degraded the flexural modulus and strength of the composites, although the mode I interlaminar fracture toughness was only marginally affected by immersion. For more details, please see the source:

-Seawater durability of glass- and carbon-polymer composites

Alex Kootsookos, A.P. Mouritz

Composites Science and Technology 64(10-11):1503-1511 (2004)

Available at: https://www.researchgate.net/publication/223102917_Seawater_durability_of_glass-_and_carbon-polymer_composites

I suggest that you prepare several samples and consider the measurement of the physical-mechanical properties at set times, with a difference of 2 / 3 months, for at least 1 or 2 years. Naturally you will have to prepare some samples that you will not exhibit and that will be your reference standard.

Furthermore, the type of exposure is not negligible: artificial sea water (or 3.5 wt. NaCl solution) in the laboratory or direct exposure in the field? In the latter case, mechanical, phisical and biological phenomena (in addition to chemical ones) will also have their effect ...

Best regards, Pierluigi Traverso

Hi;

PAMAM dendrimers display greater biocompatibility than other dendrimer families, due to the presence of the amine and amide functionalities, which give PAMAM dendrimers identical properties to those of globular proteins and antibodies.

With my best regards

The amount of sample will be reduce by half some times by quarter.

Dear Shally,

The Polyester is not commonly used at SHF frequencies. Depending on your application, I suggest using the attached substrates. Some of them work well on antenna designs up to 60 GHz or higher.

Best Regards!

Dear Manas,

The main difference between fiber grade PET and bottle grade PET is their molecular weight, which Mw of bottle grade PET is more the other one.

For bottle grade PET: MW: 24000-36000 g/mol, intrinsic viscosity: 0.72-0.82 dL/g

For fiber grade PET: Mw: 15000-20000 g/mol, intrinsic viscosity: 0.55-0.67 dL/g

Dear Shen,

I agree with you that HSP of PLA, PBS, PBAT and PCL can be very distinct, and this can be assumed by considering firstly the physicochemical differences between these biopolyesters.

The problem is more complicated, where the literature is given different values regarding the solubility parameters for the same polymer, e.g., let’s go to consider the case of PLA.

Firstly, I would recommend to use the official site Hansen Solubility Parameters (HSP) to obtain more information (https://www.hansen-solubility.com/ ). Regarding the PLA (https://www.hansen-solubility.com/HSP-examples/pla.php ): “However, with a few solubility data points from an academic journal it was possible to estimate the HSP of PLA via the Sphere fit. Although this particular fit gives HSP of [19, 10, 6] some further sanity checking gave a value of around [18.5, 8, 7].”

For instance, between the most cited values ​​(δd, δp and δH) are respectively 18.6, 9.9 and 6.0 (see as reference the book: Poly(lactic acid) Science and Technology. Proccesing, Properties, Additives and Applications (2014): Royal Society of Chemistry, Editors: Alfonso Jiménez, et al.; or as previous reference, S. J. Abbott, in Poly(lactic acid): Synthesis, Structures, Properties, Processing, and Applications, Wiley, 2010, pp. 83–93).

On the other hand, please consider that the different grades of PLA could show different behavior in traditional solvents (THF, DCM, CHCl3, etc.) point of view solubility. I believe that the molecular weights of PLA and especially the isomer purity (L- or D- isomer) in connection to the degree of crystallinity could influence (more or less) the solubility parameters, but unfortunately, for the moment these aspects are less considered in the studies realized up to now…

Good luck in finding the most helpful information,

Marius

A rare earth stir bar might work. They are much better for viscous mixtures than the standard Alnico bars.

Raman spectroscopy is complementary to IR spectroscopy.

Mass spectroscopy...