Today's KNOWLEDGE Share : Thin High shear layers in Injection molding

Today's KNOWLEDGE Share

A local temperature increase in excess of 100°C is absolutely a realistic number for the thin high shear layers in Injection Molding.

Because this high T will last often less than a second (fill-times are short, the cold steel mold is extremely close), such high melt T will not necessarily result in a very visible quality loss, like discoloration.

This high shear-heating also happens in your barrel if you push RPM and back pressure up. However, testing for melt T plunging a thermocouple on the purged melt will hardly measure a significant change in average temperature, because the very hot layer is extremely thin (small overall volume fraction).

Despite the small volume involved in possible degradation, significant issues may arise, like VOC (volatile organic compounds) degassing, which will mess with your process and parts.

The message is : be aware that due to the low thermal conductivity of plastics, heating will be very localized (adiabatic) and will be difficult to evidence with typical observation/testing, while already creating issues.

source:Vito leo

Today's KNOWLEDGE Share : Toray Develops Nylon Resin with 4X Greater Damping than Butyl Rubber:

Today's KNOWLEDGE Share

Toray Industries, Inc., announced that it has developed a damping nylon resin that maintains the high-temperature rigidity and moldability of standard nylon while delivering four times the damping performance of butyl rubber and other conventional materials.

The company has started supplying samples to customers for various components to enhance comfort in electric and autonomous vehicles. It aims to commercialize its new offering during the fiscal year ending March 31, 2027.

Superior Vibration Damping Reduces Engine Noise

While electric vehicles reduce engine noise, the demand for suppressing low-frequency road noise is expected to grow, alongside tighter exterior noise regulations. Standard thermoplastic resins have limited vibration damping capabilities, so rubber-based materials like butyl rubber are commonly used for noise suppression.

However, these materials lack thermoplasticity, making them unsuitable for secondary processing, such as forming complex shapes and parts. Additionally, their inability to maintain hardness and rigidity at temperatures up to 120°C limits their use in automotive, electrical, electronic, and other applications.

This challenge prompted Toray to explore polymer alloys that combine nylon, known for its exceptional high-temperature rigidity and moldability, with resins offering excellent vibration damping. Conventional alloy technologies produce micrometer-scale dispersion structures, which limit the ability to fully express these properties.

By leveraging its proprietary NANOALLOY™ technology, Toray achieved a co-continuous structure in which each resin phase forms a continuous network at scales of 100 to 300 nanometers. This breakthrough resulted in a nylon resin with superior vibration damping, moldability, and high-temperature rigidity.

Loss Tangent 28X Higher than that of Standard Nylon Resin

Using its advanced technology, Toray demonstrated that the loss tangent, a key indicator of damping performance, is around 28 times higher than that of standard nylon resin and four times higher than that of butyl rubber. The thermoplasticity of the new material makes it suitable for reinforced products incorporating glass fibers and other additives. Also, the material exhibits 80 times greater high-temperature rigidity than butyl rubber while maintaining outstanding vibration damping properties.

As well as replacing flexible butyl rubber-based damping materials used in gaskets and seals, the new material’s rigidity opens up opportunities for noise suppression applications in covers and larger structural components, such as chassis housings.

The new ultra-damping nylon resin should find applications in mobility components, electrical and electronic parts, industrial equipment, and construction materials.

Source: Toray/omnexus.specialchem.com

Today's KNOWLEDGE Share : Avantium Develops Solution to Effectively Recycle Polycotton Textile Waste

Today's KNOWLEDGE Share

New research leads to viable solution for polycotton textile waste recycling

In a paper published in Nature Communications, researchers at the Industrial Sustainable Chemistry group of the University of Amsterdam (UvA) present a solution to the challenging problem of recycling polycotton textile waste.

The process, developed in cooperation with the company Avantium, starts with fully removing all cotton from the fabric using superconcentrated hydrochloric acid at room temperature. The cotton is converted into glucose, which can be used as a feedstock for biobased products such as renewable plastics. The remaining polyester fibers can be reprocessed using available polyester recycling methods.

Being able to recover glucose from the cotton in textile waste is a crucial contribution to this, as glucose is a key bio-based feedstock. Currently, it is produced from starch from corn and wheat. If and when we will be producing plastics from biomass on a large scale, the world will need a lot of non-food glucose.

Scalability and cost-effectiveness:

The paper describes how Leenders performed experiments using Avantium's pilot plant for its proprietary Dawn Technology which was originally developed to convert non-food plant-based feedstock (e.g wood) into glucose and lignin. Its key feature is using highly concentrated hydrochloric acid (43% by weight) at room temperature.

Leenders tested batches of actual post-consumer polycotton waste textiles in Avantium's Dawn pilot plant. It turned out the cotton cellulose could be fully hydrolyzed into glucose under industrially relevant conditions. The polyester part of the fabric remained intact and could be easily separated. The trials demonstrated high glucose yields, indicating scalability and cost-effectiveness.

The cotton-derived glucose from the process can be used in a wide range of industrial applications, including polymers, resins and solvents. It can, for example, be used by Avantium to produce its lead product 2,5-furandicarboxylic acid (FDCA), a crucial component in the production of the biobased PEF polyester (polyethylene furanoate) that offers a renewable alternative to PET bottles.

The process also enables the complete recycling of polyester from polycotton. It can be chemically recycled to form new virgin polyester, as was established by tests performed by CuRe.

Favorable techno-economic analysis:

According to Gruter, the research lays the foundation for actual industrialscale recycling of polycotton textiles and the first commercial availability of non-food glucose.

Many parties are trying to get either of these things done but no one has succeeded yet.Our techno-economic analysis looks rather favorable and Avantium has already invested substantially in this development.

source:Avantium/ phys.org

Today's KNOWLEDGE Share :Cornell Researchers Create First-of-Its-Kind Durable and Recyclable Plastic

Today's KNOWLEDGE Share

Researchers have created a recyclable, bio-based alternative to thermoset plastics using dihydrofuran (DHF).

Cornell University researchers have developed a recyclable alternative to thermoset plastics, a durable class of materials commonly used in car tires, replacement hip joints, and bowling balls.

Thermosets are characterized by a crosslinked polymer structure that ensures exceptional strength and longevity. However, this same structure has made traditional, petrochemical-based thermosets— which account for 15% to 20% of all polymers produced—impossible to recycle.

“Currently, zero percent of the world’s thermoset materials are recycled – they’re either incinerated or thrown in landfills,” said Brett Fors, professor of chemistry and chemical biology at Cornell.

A Bio-Based, Recyclable Solution

The Fors lab has addressed that environmental challenge by creating an alternative made from a bio-sourced material that has crosslinked thermosets’ durability and malleability but can be easily recycled and degraded.

“The whole process, from creating to reusing, is more environmentally friendly than current materials,” said Reagan Dreiling, a doctoral student in the field of chemistry and first author of the paper, which published in Nature.

The Fors group studies dihydrofuran (DHF), a monomer – or chemical building block – that can be made from biological materials and has the potential to eventually compete with petroleum-based feedstocks.

How the New Material Works

Dreiling used DHF, a circular monomer with a double bond, as a building block for two successive polymerizations, the second of which results in a crosslinked polymer that can be recycled through heating and will degrade naturally in the environment.

DHF thermosets show comparable properties to commercial thermosets, including high-density polyurethane (used in electronics instruments, packaging, and footwear, for example) and ethylene propylene rubber (used in garden hoses and automotive weatherstripping).

In contrast to current petrochemical thermosets, the DHF-based materials offer a circular economy of use, Fors said. Chemically recyclable, the material can be made back into its building block monomer and used again from scratch. And when some of the material inevitably leaks into the environment, these materials will degrade over time into benign components.

The researchers are working toward applications, including making the DHF-based material useful for 3D printing. They are also experimenting to expand the properties with additional monomers.

“We’ve spent 100 years trying to make polymers that last forever, and we’ve realized that’s not actually a good thing,” Fors said. “Now we’re making polymers that don’t last forever, that can environmentally degrade.”

Reference: “Degradable thermosets via orthogonal polymerizations of a single monomer” by Reagan J. Dreiling, Kathleen Huynh and Brett P. Fors, 29 January 2025, Nature.

DOI: 10.1038/s41586-024-08386-w

The study was funded by the U.S. National Science Foundation.

source:Cornell University /SciTechDaily

A Major Step Forward with Enerkem’s Groundbreaking Waste-to-Methanol Technology

Enerkem, a global technology provider enabling low-carbon fuels and chemicals production from waste, is proud to announce that Repsol’s Board of Directors has officially approved the Final Investment Decision (FID) for the Ecoplanta project, marking a significant milestone in the drive for the supply of sustainable fuel and product.

Repsol’s Ecoplanta project will leverage Enerkem’s cutting-edge technology to transform non-recyclable municipal waste into sustainable methanol which can be used as a raw material to produce circular materials as well as advanced biofuels, contributing to the decarbonization of transport and chemicals.

“We are thrilled with the approval of Ecoplanta’s FID, which will play a key role in advancing our commitment to sustainability and circularity,” said Michel Chornet, CEO of Enerkem. “Enerkem’s innovative technology will enable Ecoplanta to make a significant impact on efforts to increase waste recycling as well as decarbonizing hard-to-abate sectors.”

Located in El Morell, Spain, the Ecoplanta facility will help tackle major environmental challenges by diverting around 400 000 tonnes of non-recyclable municipal waste from landfills and incineration. Using Enerkem’s advanced gasification technology, the facility will convert this waste into 240,000 tonnes methanol per year. The start-up of the plant is scheduled for 2029.

“Our technology has already proven its ability to convert waste into valuable, sustainable products at commercial scale, and we are confident Ecoplanta will set an inspiring example for others on the path to decarbonization. I would like to thank Repsol, Technip Energies, the European Innovation Fund* and our employees for this great achievement.

source:Enerkem

Today's KNOWLEDGE Share : Revolutionary Biodegradable Nylon Precursor Created via Artificial Photosynthesis

Today's KNOWLEDGE Share

An artificial photosynthesis technology for producing biodegradable nylon from biomass-derived compounds and ammonia has been developed.

Biodegradable plastics made from biomass-derived compounds are attracting attention as alternatives to conventional plastics synthesized from fossil fuels. Similarly, nylon, used in products such as umbrellas, fishing lines, and sportswear, is also produced from fossil fuels and does not biodegrade in nature, leading to environmental pollution. Therefore, there is a demand for alternative materials.

Professor Yutaka Amao (Research Center for Artificial Photosynthesis) and graduate student Kyosuke Yamada, a first-year Master's student in the Department of Chemistry at the Graduate School of Science, have developed an artificial photosynthesis technology to synthesize a biodegradable nylon precursor using biomass-derived compounds and ammonia. By focusing on the chemical structure of biodegradable plastic raw materials, they selected amino acids with similar structures as raw materials for nylon-type biodegradable plastics. Furthermore, they have succeeded in synthesizing this precursor using solar energy.

This research has been published online in the journal Sustainable Energy & Fuels of the Royal Society of Chemistry on November 12, 2024.

By introducing a biocatalyst for amino acid production into a photoredox system, we have succeeded in synthesizing a biodegradable nylon precursor from biomass-derived compounds. Although the experiments were a series of painstaking efforts, we are delighted to have achieved these results. We hope that this research will contribute to reducing greenhouse gas emissions and solving environmental pollution.

source:Osaka Metropolitan University

URL:https://doi.org/10.1039/D4SE01215A

Today's KNOWLEDGE Share : Epoxy resin system for Type 3/4 composite cylinders

 Today's KNOWLEDGE Share

Selecting the right Epoxy resin system for Type 3/4 composite CNG/ H2 Cylinder applications:
Epoxy resin has played a vital role in Composite overwrapped Pressure vessels applications for decades. To improve certain mechanical properties,the two component /multi component epoxy resin system is mainly focused on low viscosity and good wettability that will suit for filament winding process.While preparing the resin formulation ,the glass transition temperature(Tg), ot life,curing time has to be determined to match the entire production process.

High viscous resin will lead to improper wettability and not proper adhesion with the reinforcements(carbon fiber) that will lead to formation of air bubbles and delamination in the end product that deteriorates in the mechanical properties of the type 4 cylinders.

Low viscosity Epoxy Resin:
Low viscosity epoxy resin system is recommended with proper mixed ratios and the entire production process has to maintain proper resin content till the last layer.The fluctuations in the resin content in each layer will lead to formation of voids /delamination in the final product. Interfacial bonding in between fiber and matrix need to be planned well to avoid not infiltrate the fiber in the resin system thus leading to stress transfer failure and performance failures as well.

The importance of Curing time:
Curing time has to be followed as per the manufacturer's recommendations.The curing time is set based on the polymerization reaction in between the epoxy,hardener and accelerators. One has to adhere to the suggested curing time and follow it in the entire batch. I suggest to check the properties of epoxy resin such as potlife,Tg, etc before start the filament winding process.The properties of epoxy resin may change due to the presence of dirt and not properly stored. It is advisable to have an Expert who is well knowledgeable on epoxy chemistry.The presence of impurities/dirt might slow the down the polymerization process during curing and thus leads to have many weak spots in the laminate.That's the reason,the type 4 cylinder manufacturers to stick with curing process with maintain the recommended temperature for 2 hours/4 hours or 6 hours with different curing temperatures. For optimizing the curing process,one has to customize the over that will carry out the entire curing process with different temperatures for hours.

Do not try fabricating your own oven by yourself in the beginning of the plant set up. One small mistake or not proper functioning will make the product fail in the testing.Over heating above recommended temp time also leads to weakening the mechanical properties as well.There is no intermittent break up during curing process. It has to be one cycle properly executed.

Muthuramalingam Krishnan

Credit (Photo) :Hexagon Purus
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