Extrusion - Science method

Your observation is astute. While many flow equations for polymer extrusion don't explicitly include temperature as a variable, its influence is significant and indirectly accounted for in several ways:

1. Viscosity:

2. Pressure Compensation:

3. Screw RPM and Flow Rate:

4. Energy Consumption:

In essence, while temperature isn't explicitly included in many flow equations, its impact is significant and is accounted for indirectly through factors like viscosity, pressure compensation, and flow profile.

Add a cooling steam of air at the cutting die

Reactive extrusion for preparing high molecular weight polylactic acid continuously enhances material properties through controlled temperature, functionalization, and chain extension. This method offers environmental benefits and improves mechanical strength and thermal stability.

Hello,

A phosphate assay measures the concentration of phosphate ions in a sample. Since phospholipids contain phosphate groups, this type of assay can be used to indirectly quantify lipid levels.

· Chris Roosendaal; Polymer Extrusion; (2014); 5th Edition; Hanser Publishers, Munich; ISBN 978-1-56990-516-6 E-Book ISBN 978-1-56990-539-5

· Pierre G. Lafleur, Bruno Vergnes; (2014). Polymer Extrusion (1st ed.). Wiley. https://www.perlego.com/book/1001487

· Lewandowski, A., & Wilczyński, K. (2022). Modeling of Twin Screw Extrusion of Polymeric Materials. https://doi.org/10.3390/polym14020274.

· Kadyirov, A., Gataullin, R., & Karaeva, J. (2019). Numerical Simulation of Polymer Solutions in a Single-Screw Extruder. https://doi.org/10.3390/app9245423.

· Roland, W., Kommenda, M., Marschik, C., & Miethlinger, J. (2019). Extended Regression Models for Predicting the Pumping Capability and Viscous Dissipation of Two-Dimensional Flows in Single-Screw Extrusion. https://doi.org /10. 3390/ polym11020334.

· Roland, W., Marschik, C., Kommenda, M., Haghofer, A., Dorl, S., & Winkler, S. (2021). Predicting the Non-Linear Conveying Behavior in Single-Screw Extrusion: A Comparison of Various Data-Based Modeling Approaches used with CFD Simulations. https://doi.org/10.1515/ipp-2020-4094.

· Lin, Y., & Lee, G. (1997). System Identification for State Feedback Integral Observer Control of Polymer Plastic Extrusion. https://doi.org/10.1080/03602559708000659.

· Nasyrova, S., & Kaufman, I. (1966). Extruder flow. https://doi.org/10.1007/BF00859982.

I think that Professor Jennifer A Lewis at Harvard University has published extensively on this, so her papers may be a good source for you?

Adding phenolic resin in various concentrations during processing can affect the processing and mechanical properties of PP-EPDM-NBR blends. Recycled PP content increases the mechanical properties and flow index of PP/EPDM blends, but affects the impact strength. Carbon-black-filled NR/EPDM and NR/R-EPDM blends decrease tensile strength and elongation at break with increasing weight ratio of virgin EPDM or R-EPDM in the blend. Adding 1.5 vol% organoclay to PP/EPDM blend improved oxygen and carbon dioxide barrier properties about two-fold. Incorporating 10 phr epoxy phenolic resin (EPR) into EPDM composites enhances ablative properties by two folds and increases interfacial shear strength by 55.6%.

Phenol-formaldehyde resins (resols) are preferred crosslinking agents for dynamic vulcanization of blends of polypropylene and ethylene-propylene-diene rubber (PP/EPDM) for the production of thermoplastic vulcanizates (TPVs). Modifying phenolic resin with vinyl triethoxysilane (VTES) can reduce the MFI for EPDM/PP blends by removing glass transition and reducing the diameter of PF phase. Dynamic crosslinking with phenolic resin and tin chloride significantly improves tensile strength and tear strength in EPDM/PP blends. Blends with phenolic curing system exhibit superior mechanical and thermal aging properties, making them suitable for high-temperature engineered products.

Best Regards,

A singular matrix can result from an underconstrained problem where the number of equations is less than the number of unknowns. Ensure that your model is adequately constrained.

Hamed Ebrahimpour Dokhany

Itay, could see as a guide:

You start with a white PE that turns orange after mixing with zeolites? Sounds like a chemical reaction with additives. There will definitly be phenolic antioxidants in your PE. Do you know what additives are in your PE?

Have a look at e.g.:

Effect of Phenolic Antioxidants System on Yellowing of Amorphous Poly-?-olefin (researchgate.net)

Discoloration of polymers by phenolic antioxidants | Request PDF (researchgate.net)

Hot extrusion is not a type of creep failure, but it involves a process that shares some similarities with creep. Let me break it down for you:

Hot Extrusion Process:Hot extrusion is a manufacturing process where a material, often a metal or alloy like Al 6063, is forced through a die at an elevated temperature. The material is typically heated to a temperature above its recrystallization temperature but below its melting point. This allows for plastic deformation and shaping of the material.

Creep:Creep is a phenomenon associated with the slow, time-dependent deformation of materials under a constant load or stress at elevated temperatures. In creep, the material undergoes deformation over an extended period, and it is often observed in materials subjected to high temperatures and constant stress.

Relationship Between Hot Extrusion and Creep:While hot extrusion is not a type of creep failure, the process does involve plastic deformation of the material at elevated temperatures, and some aspects may resemble creep behavior. Here are a few points of comparison:

In summary, while hot extrusion and creep both involve deformation at elevated temperatures, they serve different purposes and have distinct characteristics. Hot extrusion is a controlled manufacturing process, whereas creep is an undesired phenomenon that can lead to failure over time.

Depends on the concentrations you are using. Low exposure levels could be stimulating the ROS scavenging pathways while the low dose is not generating as much ROS causing lower total ROS. I would suggest transfecting with roGFP reporter plasmids and seeing if you get the same result.

Al4043 will be a better option. I have performed welding of Al6061T6 with this filler wire in the MIG process and it worked fine.

You may want to check answers to a somewhat related question at this forum for its possible interest: «What are the most important parameters controlling the extrusion of pastes?»; https://www.researchgate.net/post/What_are_the_most_important_parameters_controlling_the_extrusion_of_pastes

In principle you need to find how the energy was produced in the first place. Depending on types of power plants and other energy providers processes, the GHG emissions vary.

Also have a look at the following paper for more theoretical background:

We are designing the single screw extruder to make filament for 3-D printing. We do not have the value of power as we have to select the motor with appropriate torque and standard rating from the market particularly based on the values of the calculation we made for torque and power. So how can I apply this formula? Suresh Ahuja

I'm new to the drawing process and I'm looking for the software QForm to conduct some analysis in my research.

I would like to know where I can find the software to download?

Deendayal Kumar or Karim Amellal do you have the instalation setup of this software to share with me?

Thanks in advance!

without proper dimensional inputs (billet dia, required dia, number of passes, required surface finish in microns, etc) ... it is not easy for anyone to answer your question ...

after doing centrifugation collect the solid layer and go with that.

Thank you, dear Dr. Babawati

@jama

Treatment of Lignocellulosic stock for bioethanol production requires removal of lignin barrier from Cellulose. Lignin has glassy transition temperature about 170 degrees centigrade.(Please get it reconfirmed as I have been out of touch with the subject for very long time). Heating biomass to the desired temperature and heating time are important parameters for pre-treatment of biomass.

Flow lines, streaks or flow marks are the result of flow instability that occur when the the rate of shear acting becomes higher that a critical value. Due to higher rate of shear the melt experiences higher normal stress differences causing die swell + sudden change in the temperature after melt comes out of extrusion + the adhesion between melt and die surface combine to give streaks.

Dr. B R Gupta

Dear Franklin Uriel Parás Hernández, both degradation and crystallization are behind the change in color aspect. My Regards

Hi Franklin and all.

This is a well-known case of violation of the famous “no slip condition” in Fluid Mechanics: the fluid (polymer melt in this case) slips on the walls of the extrusion machinery. Transversal velocity gradients in the melt are small so that plug-flow model (full slip flow) is used sometimes. In general, the relative rugosity of the wall surface in contact with the melt is irrelevant regarding pressure drop. In a way, it is as if Bernoulli equation holds. However, with polymer melts you have simultaneous flow and heat transfer. Look for “slip-flow models” or “polymer melts slip-flow models” at the Internet.

Kindly see also the following useful RG links:

I have been facing the same problem. What solutions did you apply?

Do you need problem statement for research?

Dear all, please have a look at the following documents. My Regards

Thanks for your response. But I can not add anything to the formulation.

yess

Dear Mohammad Reza Abbasi, grafting hydrophobic side groups is the best way as it leads to stable and permanent residues for long term stability against mainly migration. Please have a look at the following documents. My Regards

A quick check with pens and papers-

Use Euler's Buckling formula

max load P= EI*(pi)^2/L^2. L is the insertion point (into hole, box, whatever) to holding point (where the pipe is gripped and applied force. E is young's modulus. I is area moment of inertia, I=(pi/64)* (D^4-d^4). D is outer and d is inner dia of tube

This bold portion would work just fine to use the area moment of inertia of a hollow column.

For eccentric loading, use the Secant formula instead

(https://lh3.googleusercontent.com/proxy/g8_baZStGvHyY_kjl9HELONHz1gqJddFMcZayzbGxs98fjs8RGCh2SOdBy_3t-736KBrYl3BRgVjUwCGnuauyvL2x7_9N84G8L0imQal66A9UQ4hKcWBlV8o25Z5fBTBABo_HA0AeIPa54ezgH2sCeR2P4U2_G3x-Y2d4w)

But wait! if PVC tube is way too flexible to be considered to be elastomeric rather than linear elastic, there can be error, because Euler's formula was derived for linear elastic deformation of columns.

If standard simulations (Solidworks, Comsol, Ansys) seem too hard for you, go to some user friendly online simulation interfaces like simscale. Just upload 3D image of files in their simulation IDE, give input parameters, and you are done within a few minutes to hours.

Go for it.

If I understand correctly, you already mixed the two polymers and obtained the pellets of that blend. Your problem is how to avoid the agglomeration of the pellets of the blend. I think you need to dry properly the pellets before feeding the film blow machine.

For your answers, you have already tried using dry pellets. It's worked! But, you add CaCO3, too. I think as CaCO3 is a descant, it acted on maintenance of low moisture.

I think your solution is to dry the pellets only.

Dear F. Madidi, you can find valuable information from the following RG thread, in addition to the other reference. Essentially, balancing temperature/time, degree of orientation, and type of polymerization process, are the main influencing parameters. My Regards

Hi Maryam,

It happens that a portion of your lipids gets stuck in your extruder. It also happens that some volume of the whole solution stays in the extruder, especially when the extruder is dry before usage.

Before extrusion, I always extrude an empty buffer a few times to fill in all the small voids in the extruder with the buffer and not to lose the sample. With this step, I also check if everything is tight and I do not have any spill.

Also, make sure that your extruder is properly cleaned before you use it. There might be some leftover molecules from the previous usage, which stick to your lipids and make it impossible to go through. TO properly clean it, use methanol multiple times, then use chloroform for the glass and metal parts, and then put everything to the sonication bath. You can sonicate it first in methanol, second in ethanol, and third in water right before you use it again to get rid of any organic solvents left in there. If there are organic solvents in the extruder, they will dissolve your lipids.

That's everything that comes into my mind. Good luck in making it work!

Dear Vibhu Sharma,

Do you want to use a wire flame spray gun for thermal spraying? Thermal spraying with wire/rod is based on melting and atomizing the material. This means that your nano powder will be melted and its "nano" structure will no longer exist. In the event of the molten particle spraying, you can use a conventional powder with the same result.

Philip Rolfe

Hi Phil,

Thank you very much for this assistance, the paper is a great help.

Once again, many thanks

Matt

Magnesium alloys are corrosion resistant and etching is based on differential corrosion response shown by the grain boundaries. Freshly prepared etchants and also freshly polished specimens are used to obtain better results. Increase the etching time or re-polishing after etching and then etching can be performed.

About several parameters that may possibly influence extrusion of ceramic pastes, you may check answers to another question at this forum ̶ «What are the most important parameters controlling the extrusion of pastes?»: https://www.researchgate.net/post/What_are_the_most_important_parameters_controlling_the_extrusion_of_pastes

Greetings. Sadiq Gbagba thanks for your answer, much appreciated.

I tried the method you've shared, and I think there's progress. The Freeze tool is quite an interesting tool; didn't know it even existed. So I froze the model, and then performed a, 'Thin' on the outer circle.

The die system is the heart of extrusion or co-extrusion of films and there is a relation between the width of the die & the thickness of the film emerging by casting.

Please see this article:

http://www.macroeng.com/fundamentals-of-cast-film-extrusion-technology.php

Of course yes and there are several papers on this topic. The reference you presented is one among several that in fact have higher relevance than this one.

I think an increase in moisture of premix can help to alter pressure-temperature parameters.

I come back to the discussion based on recent results.

Micronizing our mixed rigid/flexible PVC scraps (100-300 um) in respect to roughly grinded scraps (in the order of mm/cm) has led to unespected results (at least to me).

At DSC we can see a single Tg (that is a single phase) when extruding grinded mix at 190 °C. With pulverized mix it is necessary to go at 210 °C to see a single phase.

How we can explain that with pulverized mix it is necessary an higher extrusion temperature to get an homogeneous mix?

Also check https://onlinelibrary.wiley.com/doi/abs/10.1111/jfpe.12961

I presume you have balanced the MD and XD properties already?

Increasing gauge (film thickness) didn't do what you want?

An increase in molecular weight should bring up dart impact, and if balanced by an increase in density...maybe, maybe you can keep elongation (in a tensile test) constant.

What's wrong with an increased elongation at failure?

In my opinion, the properties modification could be achieved by the components ratio rather than extrusion conditions. According to patent https://patents.google.com/patent/CN101111375B/en you could produce film with Dart impact 150 g/mil.

Do you have to use PLA? because, a different kind of biopolymer could be easier to process, something that has certain proportion of PBAT or something like that. PLA, as you mentioned, might be too stiff, and grades that are specifically designed for Blown Film Extrusion have to have something that lowers the stiffness of the polymer.

Miguel Angel Romano

Plastic processing specialist.

Chemical Engineer.

7 years as Blown Film Specialist and formulator.

Dear F. Madidi, are these polyolefins extrusion-blown films grades? My explanation is that may be either the MW is low and/or having a broad MWD. As you know shrink-wrap is a relaxation of highly oriented chains, so MW and MWD are the premordial parameters. My Regards

Hi

I think this should help. I also include some other references working on the same idea but maybe not with PE but say PP.

At 11-25% CaCO3, dart impact improves over neat resin, but it drops below neat resin at filler levels up to 10%. Dart impact can also improve dramatically with higher loadings, depending on the resin type. At 20% CaCO3, dart impact for a 15-micron butene-copolymer LLDPE is 100 gm, slightly higher than that of unfilled film at 75 gm. Hexene copolymer, however, gets a big boost in dart impact with 20% CaCO3–rising to nearly 500 gm from 150 gm unfilled. Octene LLDPE also jumps to 500 gm dart impact with 20% CaCO3, from 200 gm unfilled.

Additional:

Dear F. Madidi, the following documents provide major influencing factors on the dart impact. My Regards

Thankyou for guiding. I will do it and based on the outliers, I will decide what correlation coefficients or MAE is to be used Andrey Davydenko

Sometimes it's better to play with mesh/material frames while defining the extrusion couplings.

With the use of "minimum" coupling feature in comsol along with the proper definition of displacement local variable defined by "contact" node in the structural mechanics I think this could be done.

Dear Abin Alex,

It's a very very important question related to engineering and technology.

The basic idea lies in Physics.

We know the measurement procedure of resistivity of any arbitrary shape of two dimensional object by Van der Pow method.

But , for three dimensional object , I am also trying to find a solution of Calculation of the resistance.

I tried to calculate the resistance of a solid sphere between two diagonally opposite points. But it's so lengthy process.

I am not satisfied. For the any two corner point of a cube, I don't find any solution.

Thanks

N Das

Hi

you must fill these parameters with experimental data or Articles which contain information about your material.

you can search about grain avrami model, arhenius equation to achieve some information.

if you are eager to know more, you can read my article.

This is the link:

Hello Dr. Chaitanya Krishna ,

Thank you so much for the insightful suggestion, this could be a better alternative i guess. Thanks again sir.

Try with some water , this also has plasticating effect and partial foaming of your blend , but reactions could be also with your other additives.

You welcome

Regards

Cristo

Dear Shravan,

I am not sure if the question is still of interest to you, but I would like to say a few things. I hope they will be relevant.

In the case of the dynamic properties, I would suggest you consider your geometry as coaxial cylinders and apply the Reiner-Riwlin equation. Please check out this paper by Dimitri Feys et al.: Extension of the Reiner–Riwlin equation to determine modified Bingham parameters measured in coaxial cylinders rheometers.

In the case of the static properties, you can use the following simple equation to calculate the SYS: τ = T/(2*r²*π*h), where r and h are the radius and the height of the probe. Here we consider that only a small region in the vicinity of the probe is sheared, which will be the actual case if you are testing stiff 3DP concretes. The equation will not change depending on using single-batch or multi-batch approach. What can change is the determined value of A_thix, especially if you test a highly thixotropic mixture with a high volume fraction of aggregates. Then the single-batch approach will give you underestimated results. However, this approach is basically the only one you can apply to control A_thix of your 3DP concrete by means of rotational rheometry, unless you have multiple identical rheometers in the lab, of course :)

Regarding your comment on giving torque and rot.velocity instead of SS and SR, I would like to say that they can be very different for different tools, therefore, other researchers who are using another rheometer will not be able to get what your values are representing. That is why we all try to present SS and SR. It gives us a feeling of the mixture's properties.

Good topic dear,

We need other scientists to know more about that

Do you have access to ion beam etching facilities? We usually finish the "tricky" Al samples with some Ar+ ion beam etching.

There is only one way to be certain. Solve the structure of the material. Scrape the surface onto a carbon coated grid and use micro diffraction techniques in a tem or backscatter diffraction techniques in an sem. The material may be beam sensitive so good luck but there is only one way to be certain, solve the crystallography.

Sorry，I don't do this work.

Javier Solorza-Feria

I looked at your interesting work. You are already a famous scientist. Your mix is complicated.

If you have a Cloisite 30B nanoclay, then you can see the article.

Air bubbles can only be in clay. Glycerol molecules can penetrate there. Molecules in nanopores behave unexpectedly, for example, water molecules in nanopores of beryl.

Regardless the software, the more accurate you simulate the case, the more accurate the results you get, accordingly modeling tendons as solid is more accurate than wires especially in bonded per-stressed elements. But in this case, you have to model the anchorage system as solids also. n other hand wire element is much simpler and easier to model.

So, if you are modeling the whole structure you may use wire modeling, but if you are modeling a limited zone such as anchorage zone of coupling zone you may use solid element.

good luck

David W Chester

You can experiment with an aqueous solution of ethyl alcohol instead of water to obtain vesicles. With an increase in the alcohol content in water to 0.1 mole fraction, the hydrophobic interaction is enhanced. The addition of urea weakens the hydrophobic interaction.

The entire Chapter 5 titled Preparation of filled polymer systems pages 175-242 in the book Aroon V. Shenoy, Rheology of Filled Polymer Systems, Kluwer Academic Publishers, Netherlands (1999) is dedicated to the mixing/blending/compounding of fillers into polymer melts. The sections include Goodness of mixing, Mixing mechanisms, Compounding techniques, Compounding/mixing variables. In section 5.4, there is a detailed discussion on the compounding /mixing variables that affect the quality of the mix. Some variables are more sensitive to changes than others. It is important to study and identify these variables and understand their sensitivity so that the compounding /mixing can be carried out under optimum conditions. Variables affecting compounding operations could be machine variables (mixer type, rotor geometry) or operating variables (mixing time, rotor speed, ram pressure, chamber loading, mixing temperature, order of ingredient addition). You will have to study and understand the effect of each of these variables for your specific metal nanoparticle filler – ABS polymer matrix combination to find the optimum conditions to achieve the proper level of dispersion and distribution of filler into the polymer. You will get the necessary hints on how to go about this by reading Chapter 5 of the book.

In the Table 1.12 of the book Aroon V. Shenoy, Rheology of Filled Polymer Systems, Kluwer Academic Publishers, Netherlands (1999), there are many suggested surface modifiers that would work for the ABS matrix – A-174, A-187, CM8550, CG6720, MEMO, GLYMO, Z-6030, Z-6040. These are silanes, and their full forms are given in Table 1.8. Which one would be most effective for the metal nanoparticles that you are using can only be worked out by some mixing experiments, which are discussed in the book.

Further, in case you need to understand the important factors in preventing flow defects and controlling the quality of the material that is produced during extrusion process, then you may get some idea about it by reading the Section 8.4 of Chapter 8 on Extrusion in the following book: A. V. Shenoy and D. R. Saini, Thermoplastic Melt Rheology and Processing, Marcel Dekker Inc., New York (1996). Twin-screw extrusion may be better than single-screw extrusion for achieving better dispersion and break-up of agglomerates. Running the same material twice through single-screw extrusion may not provide additional benefits like what twin-screw extrusion would provide in a single run.

Hai.,

Kindly check this link: