Today's KNOWLEDGE Share :How Polymer blends get unique properties

Today's KNOWLEDGE Share

Ever wonder how polymer blends get their unique properties?

It all starts with the fundamental thermodynamics dictated truth that most polymers are immiscible – they simply don't mix, with rare exceptions like PMMA/PVDF.

In these immiscible blends, the continuous phase often determines the material's thermo-mechanical, chemical, and even aesthetic properties.
The dispersed phase acts more like a filler.

But how do you predict which polymer will form that continuous phase?

It's not just about which polymer is present in a larger volume!
Viscosity is a critical factor.
A lower viscosity polymer tends to become the continuous phase.

Take a 60/40 PC/PBT blend, for instance: if the PBT is a high-flow lubricant (to the PC phase), its lower viscosity can make it the continuous phase, even if it's the minority component.

Key considerations:
- Ensure your blend ratios are expressed by volume, weight ratio at room T would be misleading.
- Volume ratios are only meaningful here at processing temperatures, since PBT, a crystalline polymer, will shrink 3X more than PC when solidifying!
- Compatibilizers are crucial for controlling the fineness of the dispersed structure.

Of course high shear in Injection Molding will modify the blend morphology, sometimes to the point of phase inversion, if one component is way more shear-thinning than the other for instance.

Hydrodynamic forces in the flow will always push the low viscosity component towards the outer layers of the flow (minimum total energy).
This can sometime lead to delamination failure of the molded part, a well known issue when molding Xenoy in automotive bumpers.

The dispersed phase will also depart from spherical inclusion shape and possibly show very elongated morphologies, especially in the “frozen skin”.

The very unique “co-continuous” morphology is very difficult to obtain reliably in Injection Molding because of processing effects mentioned above.

Note also that in all immiscible blends, a small fraction of each polymer is miscible with the other one, which can be studied in a phase diagram.
For entropic reasons, lower molecular weight grades are always more miscible than higher molecular weight grades.
So in a given blend, the short chains in the distributions are responsible for the partial miscibility observed, contributing to the structural integrity of the blends and a small shift to the two glass transition temperatures..

source : Vito leo

#polymers #polymerblends  #mixturemorphology

Today's KNOWLEDGE Share : HISTORY OF NYLON STOCKINGS

Today's KNOWLEDGE Share

When Nylons Came to Town

It took about 10 years for DuPont to turn the invention of polyamide into nylon stockings for the consumer market, but boy did it pay off.

When the first nylon stockings, made from a material invented by DuPont, came to the US market in 1940, they were an immediate smash success. As hemlines continued to rise in the 1930s, silk and rayon stockings became a necessity in many women’s wardrobe, but they were expensive and had to be replaced frequently. When department stores stared selling low-cost nylon stockings nationwide on May 15, 1940, most locations were sold out by noon, according to Distillations magazine from the Science History Institute. By the following year, Dupont sold $25 million worth of nylon yarn, and two years later it had captured an astonishing 30% of the full-fashioned hosiery market. In terms of material science, the origin of that material dates back to 1930, when an organic chemist by the name of Wallace H. Carothers joined DuPont, where he focused on polymerization research.

The first nylon:

On May 24, 1934, one of Carothers’ researchers “successfully pulled a fiber of a polymer based on an aminoethylester. His fiber ultimately the first nylon  retained the remarkable elastic properties of polyester [formulated four years earlier by Carothers’ group] but lacked their drawbacks. However, since the intermediate used to form the polymer, aminononanoic ester, was tremendously difficult to produce, Carothers and his associates kept looking,” writes Distillations. Shortly afterwards, they settled on polyamide 5,10 and polyamide 6,6. The rest, as the cliche goes, is history . . . but, in fact, DuPont still had to overcome several obstacles before reaching that commercial milestone.

The company had to perfect melt spinning under high temperatures to form the filaments, design generators to run the windup of the yarn at high speeds with almost no variation, and develop a surface coating that would not gum up the machines. An article on the American Chemical Society website explains this in much greater detail for those who want to take a deeper dive into the genesis of nylon.

When DuPont had just started reaping the commercial rewards of all this R&D work in 1940, it had to shift nearly all of its nylon production to the military in 1941 to support the war effort. The material was used for everything from parachutes to mosquito nets, reports Mental Floss in its abbreviated history of nylon. Nylon stockings, along with chocolate bars and cigarettes, were also among the coveted goodies that GIs distributed to German citizens, rare luxuries in a decimated population that initially feared retribution.

The nylon riots:

Immediately after the war when production resumed to satisfy consumer demand, lines formed outside of department stores that, according to Mental Floss, dwarfed Black Friday queues and sparked what became known as the “nylon riots.” In Pittsburgh, 40,000 people lined up for more than a mile vying for 13,000 pairs of nylons, according to the Smithsonian magazine.

Carothers, sadly, did not live to see the remarkable success of his invention. After battling depression for several years, he committed suicide in 1936.

source: Norbert Sparrow-Plastics Today

Today's KNOWLEDGE Share : One Part Silver Filled Electrically Conductive Epoxy Passes ISO 10993-5 Standard

Today's KNOWLEDGE Share 

Master Bond launches silver-filled epoxy for medical device manufacturing

#Master Bond EP3HTSDA-2Med is a true one component epoxy that is not pre-mixed and frozen. It offers an easy dispensing profile with an exceptionally long working life at room temperature, making it ideal for streamlining automated assembly. As a #silver filled system, it exhibits high electrical conductivity (volume resistivity < 0.001 ohm-cm) and excellent thermal conductivity. This epoxy passes ISO 10993-5 for cytotoxicity and is designed for high-speed #medicaldevice manufacturing.

EP3HTSDA-2Med cures quickly with heat. Cure schedule options include heating at 250°F for 20-30 minutes or 300°F for 5-10 minutes, with an optional post cure to optimize overall performance properties. The system bonds well to many substrates, including but not limited to metals, ceramics, plastics, and silicon dies.

EP3HTSDA-2Med has an excellent physical strength profile. It provides a tensile strength of 3,000-4,000 psi and a tensile modulus of 200,000-250,000 psi. It has a thermal conductivity of 45-49 BTU•in/(ft2•hr•°F) [6.5-7 W/(m·K)]. The filler particles used in this #epoxy are exceptionally small, averaging 2-3 microns, and no larger than 25 microns. This allows for very thin bond lines, thereby providing effective heat transfer since it can offer a very low thermal resistance of 2-3 x 10-6 K•m2/W. This epoxy resists many sterilization methods such as glutaraldehyde, ethylene oxide (EtO) and gamma radiation.

The system is available in EFD® syringes for automated dispensing or glass jars in 20 grams, 50 grams, 100 grams, 1 pound and multiple pounds.

source: Master Bond

Versalis opens Hoop® demo plant for chemical recycling of plastics to start at Mantua

Versalis, Eni’s chemical company, unveiled today, at its Mantua site, a demonstration plant based on Hoop®, the company’s new proprietary technology for the chemical #recycling of #mixedplasticwaste.

This technology, which complements mechanical recycling, makes it possible to convert mixed plastic waste into feedstock that can be used to produce new plastic materials suitable for all applications, including food contact packaging and pharmaceutical packaging.

Hoop® was developed through a joint project with the Italian engineering firm S.R.S. (Servizi di Ricerche e Sviluppo), leading to an innovative technology that achieves high material recovery yields and offers excellent flexibility in terms of input materials.

This is made possible by combining a high thermal performance pyrolysis reactor with Versalis’s expertise in polymer property analysis and production process optimisation through Artificial Intelligence systems.

Construction of the Hoop® demonstration plant, which occupies an area of approximately 5,000 square metres within the Mantua site, began at the end of October 2023. During the construction phase, more than 25 specialised contractors were involved, with an average daily workforce of around 70 people. In recent weeks, the first production tests were successfully completed.

The plant is capable of processing 6,000 tonnes of secondary raw material per year and will serve to validate the technology application on an industrial scale. Under the Memorandum of Understanding on the Eni-Versalis Chemical Transformation Plan signed last March with the Ministry of Enterprises and Made in Italy (MIMIT) a 40,000-tonne facility is planned for construction at the Priolo site in Sicily. The feasibility study has already been completed and the design phase is currently under way in preparation for the start of the permitting process.

“Today we are giving further substance and value to circularity, one of the pillars of #Versalis’s transformation plan”, said Adriano Alfani, CEO of Versalis. “The Hoop® plant we are opening today is a symbol of the path we are following – harnessing innovation to reshape our business through new industrial initiatives based on circularity, biochemistry and specialisation, in pursuit of increased sustainability. We are committed to addressing all three of sustainability core dimensions: environmental, social and economic.

SC-HOOP, Versalis’ project name for the realization of the demo plant based on Hoop® technology at Mantua, is the only Italian large scale project to be awarded funding in the 2023 EU Innovation Fund* call, out of 239 proposals submitted and 41 selected overall. The Fund established by the European Commission, supports innovative low-carbon technologies. The patent has also been selected by the Ministry of Enterprises and Made in Italy to be showcased among Italy’s successful innovations.

source: Versalis

Ensinger to invest in a second polyimide TECAPOWDER site

Plastics processor Ensinger is increasing the production capacity of its TECAPOWDER product line. The polyimide material will be produced not only at the company’s site in Lenzing, Austria, but also in Obernburg am Main, Germany. The new production line at the Industrie Centre Obernburg (ICO) is expected to be operational by 2027.

TECAPOWDER is a high-temperature polyimide that is characterised by its complete solubility, excellent filler properties and outstanding thermal stability. Due to its wide range of applications, including composites, PTFE matrix systems, battery technology and the aerospace industry, demand for it has risen steadily in recent years.

Capacity limits have now been reached at the development and production site in Lenzing. To enable further growth, Ensinger began looking for an additional production site at an early stage. As special solvents are used in the production of TECAPOWDER, a chemical-specific infrastructure is essential. The ICO's technical equipment offers ideal conditions for producing polyimide powder.

"With the new site in Obernburg, we are creating the basis for further growth while also increasing our supply security. In future, we will be able to supply our customers flexibly with TECAPOWDER from two production sites," says Sylvia Mücke, Head of Special Products at Ensinger.

"We are delighted to have gained Ensinger, a cutting-edge family business, for the ICO. In addition to the infrastructure and media such as process heat, electricity and water, we are also providing Ensinger with various services," says Sebastian Krug, Head of Site Development at Mainsite. 

Ensinger offers the TECAPOWDER product in various grain sizes and degrees of refinement, and can also provide customised solutions on request.

source: Ensinger

Today's KNOWLEDGE Share : PFAS could be replaced with safe graphene oxide solution

Today's KNOWLEDGE Share

PFAS could be replaced with safe graphene oxide solution

Northwestern University researchers have developed a new water- and oil-resistant material that could become a safe, viable replacement for harmful plastics and toxic per- and polyfluoroalkyl substances (PFAS) in food packaging.

Derived from graphene oxide, the material is non-toxic, environmentally friendly and affordable.

When applied to paper-based food and beverage packaging, the material not only provides exceptional barrier properties but also significantly enhances the product’s overall strength. This could mean an end to flimsy paper plates and soggy takeout containers. After use, packaging treated with the material can be readily composted or recycled — closing the loop on a truly sustainable solution.

GO-Eco — a subsidiary of Chang Robotics and a resident startup at Northwestern’s Querrey InQbation Lab (The Q) — is commercializing the patent-pending product.

Recent independent, third-party industry-standard evaluations have shown that Northwestern’s material significantly improves strength and barrier properties compared to current commercially available solutions.

A transformation in how we package food

“This is not just a materials innovation; it’s a market-ready solution,” said Timothy Wei, who co-developed the product. “We are thrilled to be taking GO-Eco from the lab to the factory floor, with applications that could ultimately transform the entire food packaging industry.”

Wei is an adjunct professor of mechanical engineering at Northwestern’s McCormick School of Engineering, chief scientist at Chang Robotics and former dean of engineering at the University of Nebraska-Lincoln. He co-developed the product with graphene oxide expert SonBinh Nguyen, a professor of chemistry at Northwestern’s Weinberg College of Arts and Sciences.

The urgency for new solutions is clear. After analyzing numbers from various sources, the GO-Eco team estimates the U.S. alone produces approximately 14 million metric tons of paper-based food packaging and corrugated cardboard each year, generating more than $60 billion in annual sales. These products are often coated with plastic, foil or PFAS to achieve water- and oil-resistance, despite mounting regulatory pressures to eliminate these materials due to environmental and health risks. While some bio-based alternatives exist, their high cost has rendered them commercially unviable.

Improving the barrier properties of paper and cardboard

The potential solution to this global problem came from decades of research from Nguyen’s and Wei’s labs. While Nguyen’s research group has published extensively on characterizing and manufacturing graphene oxide, Wei brings deep expertise in advanced manufacturing and the food industry. Together, they developed a new proprietary process that harnesses the unique properties of graphene oxide — oxidized single-atom-thick sheets of carbon atoms — to enhance the barrier properties of paper and cardboard products.

After developing the process, the team rigorously tested the material on a diverse range of food- and beverage-packaging prototypes, including cardboard boxes, plastic produce bags and disposable tableware, such as plates, cups and straws. In every instance, the new material rendered these products resistant to water, oil and grease, while simultaneously boosting the strength of the paper substrates.

Testing the product

With recent funding from a major national tableware manufacturer and active engagement from multiple industry partners, GO-Eco has advanced product testing from the laboratory stage at The Q to comprehensive, industry-standard evaluations at Western Michigan University’s Paper Pilot Plant. These tests confirmed that applying small amounts of graphene oxide increases barrier performance and paper strength by 30 to 50% over what is commonly used in the market. And the cost remains comparable to current commercial barrier products. These findings apply to a broad array of materials from molded fiber products, such as tableware, to corrugated cardboard packaging.

Through an exclusive licensing agreement with Northwestern and support from The Q, GO-Eco is transitioning the science into a commercialized technology. The team is actively discussing production and pilot testing with several companies. GO-Eco’s next steps include scaling production, pursuing FDA food-contact approvals and certifying the recyclability and compostability of paper treated with graphene oxide. It also plans to conduct a full-scale production trial for molded fiber and traditional paper-sheet prototypes.

Intellectual property associated with the graphene oxide technology is subject to an exclusive license between Northwestern and Chang Robotics and its affiliates. Nguyen and Northwestern University have financial interests (equity) in Chang Robotics.

source: Northwestern University

Today's KNOWLEDGE Share : CAI Performance Additives launches flame-retardant synergist for PVC wires & cables

Today's KNOWLEDGE Share

CAI Performance Additives launches flame-retardant synergist for PVC wires & cables

CAI Performance Additives announced the launch of ST-FR6, a flame-retardant synergist for PVC wire and cable applications.

ST-FR6 offers a cost-effective, stable alternative to Antimony Trioxide (ATO), addressing supply chain challenges while maintaining top-tier flame retardant performance and environmental safety.

The challenge with ATO:

Over the past two years, ATO prices have surged by over 50%, with global supply chain bottlenecks causing severe shortages. Manufacturers face skyrocketing costs and uncertain lead times, creating an urgent need for a reliable alternative.

Key Benefits of ST-FR6:

Lower Cost, More Stability: Reduces raw material expenses by up to 50% while ensuring supply reliability.

Proven Fire Resistance: Passes VW-1 flame test while maintaining essential electrical and mechanical properties.

Sustainability & Safety: RoHS-compliant, significantly reducing lead (Pb), arsenic (As), and mercury (Hg) content.

Seamless Integration: Works as a true drop-in replacement with no changes to existing compounding processes.

With ST-FR6, we offer a game-changing solution that helps wire and cable manufacturers stabilize costs and enhance product safety,” said Torey McCleskey, COO of CAI Performance Additives. “By eliminating reliance on ATO, we provide customers with a more sustainable and predictable supply chain option.

Source: CAI Performance Additives/SpecialChem

 

Syensqo Unveils First PFA-Free FFKM Polymers

 Syensqo Unveils First PFA-Free FFKM Polymers

Syensqo has introduced the industry's first peroxide-curable #FFKMpolymers manufactured completely without fluorosurfactants from the PFAs family of chemicals, the company announced last week.

The materials, developed using #Syensqo's proprietary Non-Fluorosurfactant (NFS) technology, represent a significant advancement in the company's expanding NFS FFKM portfolio, which earlier this year launched nitrile-curable FFKM grades for semiconductor applications.

These new materials respond directly to the seal and o-ring industry's growing demand for sustainable supply chain solutions that maintain critical performance characteristics. The peroxide-curable technology specifically targets the increasingly aggressive conditions required in advanced semiconductor manufacturing.

With our new peroxide-curable FFKM innovation, we are proud to offer groundbreaking solutions to our customers, empowering them to maintain material efficiency and integrity under extreme conditions," said Andrew Lau, senior executive vice president of Electronics & Industrial at Syensqo Specialty Polymers GBU.

Designed for a range of environments:

The NFS FFKM solutions are engineered for both dry and wet fabrication processes, delivering performance in environments exceeding 320°C and under intense plasma conditions. Beyond semiconductors, the chemical resistance properties make these materials suitable for demanding energy, transportation and industrial applications.

Manufactured at Syensqo's Spinetta, Italy facility, the Tecnoflon FFKM NFS portfolio represents the culmination of multi-year research efforts to eliminate fluorosurfactants while maintaining performance standards.

The company has made Tecnoflon PFR X7000 and X7100 available for trial, while the first nitrile curable grades Tecnoflon PFR X6055B, X6160B and X6265B — are already commercially available and being utilized throughout the semiconductor industry.

The company continues to focus its innovation efforts on battery safety and DC fast charging technologies, which are critical enablers for the growing battery electric vehicle market.

source: Plastics Today