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Triphenylphosphite (TPP) has been used as a chain extender to regenerate polyethylene terephtalate (PET) and high density polyethylene (HDPE) wastes and to improve the properties of PET/HDPE system based on recycled materials. TPP incorporation in PET and HDPE showed a noticeable increase of the torque as a function of the mixing time and proved th...
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... result is essentially due to the fact that TPP acts as an antioxidant for HDPE but as a chain extender for PET. So, more there is R-PET in the blend, the higher is the torque (Figure 3). The increase of the torque is also evidenced by the decrease of the MFI of the regenerated homopolymers and blends (Figure 4). ...
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This article is concerned about change of elastic modulus as a function of raster angle used in the fused deposition modeling and applicability of laminate theory to prediction of the elastic modulus. Polyethylene terephthalate glycol (PETG) was used for the experimental testing. In view that PETG shows viscous deformation which was not considered...
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Citations
... Melt Flow Rate (MFR) has been claimed to be related to PET degradation [41]. Although it is not a direct measurement of the polymer's viscosity, it is commonly used as an approximation [42][43][44]. Then MFR tests were carried out following ASTM D 1238-10 [45] procedure B, in an Instron brand equipment, model MF10, using a weight of 2.16 kg at 250 °C. Also at least 5 samples of each material were evaluated. ...
Plastic materials are essential in modern societies, and their recycling is a very important step in the transition towards a circular economy. PET (polyethylene terephthalate) is currently considered one of the plastics with the greatest potential for recycling due to its good properties and ability to be processed by industrial methods. However, those processes may deteriorate PET properties, since they involve high temperatures and shear stresses that together with the presence of moisture (due to the strong hydrophilic nature of PET) can provoke hydrolysis of the polymer with a corresponding loss in molecular weight. When working with recycled PET the excess moisture contained in the material may be higher. It is evident the huge importance of the drying stage in the processing of this resin. However, it has not been yet studied the influence of different techniques on the final mechanical properties of processed parts and on the processing cycle (time/costs). In this work, two drying techniques were applied: a convection oven—widely used in the industry—and an infrared oven. The aim was to study the influence of this part of the processing cycle on the final mechanical properties of PET parts obtained from both virgin material and waste soda bottles. Results confirmed that drying by infrared technology reduces drying time by 80% which implies a drastic reduction in total processing time for both types of PET (virgin and recycled). Even though no significant differences were found in the conventional and non-conventional mechanical properties, differences in the propagation mode under fracture were noticeable. These were found to be due to unintentional esterification reactions induced by IR radiation in thick materials, probably due to heat concentration, that should be taken into account when this drying technique is intended to be used.
... The Melt mass-Flow Rate (MFR) indicates the ease of flow of the melt of a thermoplastic polymer. It is defined as the mass of polymer, in grams, flowing in ten minutes through a capillary of a specific diameter and length by a pressure applied via gravimetric weights for different, prescribed temperatures [8]. It is one of the most important properties for processing a thermoplastic material especially by injection moulding. ...
Laser technology offers many advantages when removing paint (coating) layers from different substrates such as metals, plastics or ceramics. Sensitive carriers with a low melting point like thermoplastic materials can easily be thermally damaged or destroyed using this technology. This paper analyses the quality of the thermoplastic material after removing the thermoset layers from its surface by laser and aims to identify the changes of the most important properties of the polymeric material. The physical-mechanical properties of thermoplastic materials which were coated were investigated before as well as after the removal of the coating layers and compared with parts which were not coated. The focus was on melt flow rate, impact strength, and tensile stress as well as strain. The results show that even a small amount of the paint (coating) can change the behaviour of the thermoplastic material and thus has an impact on further processing. Moreover, it was found that removing the thermoset coating from the thermoplastic material leads to a considerable improvement of its physical-mechanical properties and consequently also extends the possibilities of recycling (reuse) of this polymeric material.
... Due to the high consumption of PET products and its non-biodegradable nature, it raises many environmental problems, with a high interest in recycling and reuse. However, during recycling, PET suffers thermal and hydrolytic degradation, which leads to a lower molecular weight and, implicitly, to poor mechanical, thermal properties (Guessoum et al., 2013). In this regard, to improve these properties, many research studies have focused either on mixing with one or more polymers or on the addition of reinforcing agents. ...
Recycling polyethylene terephthalate (PET) bottles post‐consumption is highly desirable but remains challenging because of their poor properties after recycling. Using a chain extender to rejoin the cleaved polymer chains is considered a reasonable solution to this issue. However, the functionality of the chain extenders affects the cross‐linking and properties of the resulting products. Therefore, this study focuses on the effects of functional groups and number of chain extenders on the properties of recycled polyethylene terephthalate (rPET). Three commercial chain extenders—methylene diphenyl diisocyanate (MDI), triphenyl phosphite (TPP), and Joncryl (JC), represented as di‐, tri‐, and multi‐functional chain extenders, respectively—are introduced into rPET by reactive blending. The intrinsic viscosity, rheological properties, thermal properties, and mechanical properties of the chain‐extended rPET are investigated. The results indicate that all the chain extenders increase the molecular weight of rPET. Di‐ and multi‐functional chain extenders (MDI and JC) induce branching and cross‐linking owing to the highly reactive functional groups, whereas a tri‐functional chain extender (TPP) showed the lowest improvement in mechanical properties, owing to chain scission from by‐products occurring during chain extension. Furthermore, increasing the content of all chain extenders significantly increased their intrinsic viscosity, cross‐linking, and mechanical properties.
This work reports the thermal, rheological, and crystallographic structural behavior of recycled polyethylene terephthalate (rPET) derived from bottle waste. The intent is to optimize it to an upcoming source for additive manufacturing by modulating its behavior using a chain extender triphenyl phosphite (TPP), nanofiller montmorillonite (MMT K‐10), and catalyst antimony trioxide (Sb2O3). FT‐IR (Fourier Transform Infrared) analysis showed an increase in absorbance due to the Sb2O3. The thermal analysis of the rPET using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) ascertains a 10°C decrease in Tg with a substantial increase in the degradation onset of 7°C due to MMT content. The melt flow index (MFI) study showed an increase with a similar range in intrinsic viscosity and weight average molecular weight (Mw) due to the additives. The percentage crystallinity, interlayer distance, and average crystallite size are determined and analyzed by X‐ray diffraction (XRD) and DSC curves. The results are within the comparative range of both tests. The presence of Sb2O3 with higher MMT content showed agglomeration, and increased TPP showed low crystalline properties. These results provide that rPET can be altered to manufacture feedstock to suit different 3D printing techniques for prototyping.
Owing to its properties, poly(ethylene terephthalate) (PET) became one of the most widely used plastic after olefins having applications mainly in packaging industry and ironically has contributed approximately 80 % part of solid waste. This generates a huge amount of waste which piles up in the environment. The processing and end-use cause thermal and mechanical degradation of PET which is then overcome by either blending or by incorporation of fillers. The use of recycled PET as a reinforcement component in elastomers enhances the performance of the resultant blend. The present work describes the preparation, processing and characterization of blend based on SEBS and recycled PET. Addition of 25 % rPET into SEBS matrix results in 31 % rise in tensile strength. The blend was further compatibilized using EMAA. Addition of 10 phr EMAA into the optimized system leads to 42.37 % increment in tensile strength. Further studies from results were analyzed at microscopic scale (SEM, DSC, TGA) and macroscopic scale (rheology and mechanical properties).
