Today's KNOWLEDGE Share :Crystallization Kinetics

Today's KNOWLEDGE Share

How does crystallization kinetics possibly influence the PvT data we use in all our molding simulations ?

PvT are typically obtained, in theory, under "thermodynamic equilibrium" conditions. This means at speed so low that kinetics should be irrelevant.

The molding process is the complete opposite ! Very fast cooling will shift crystallization T to lower values. And, as also depicted in the figure, the solid state density will be lower (so specific volume, the Y axis, higher for the red curve).

Implementing crystallization kinetics in Flow Simulation is therefore quite a big challenge since cooling rate will be different from part to part, molding condition to molding condition, as well as within the same part (thin vs. thicker areas cool at different rates for instance and temperatures are different throughout the melt).

People who have attempted to implement such "dynamic PvT" or "fast PvT" often neglect to account for the extremely strong nucleating effect of shear-stress in the outer layers. Any DSC (quiescent) crystallization kinetic data will fail to predict the true kinetics observed under the very high flow stresses of Injection Molding.

Pressure is also a well known nucleating "agent" (speeding up crystallization, as seen in the classical horizontal shift of the transition zone in PvT data) but will also increase the Glass Transition temperature of the material which results in the opposite effect of slower molecular diffusion (higher viscosity) and hence somewhat slower crystallization.

Quite some work ahead of us to further improve the accuracy of Injection Molding without actually deteriorating the simulation performance by forgetting important pieces of this complex Physics !.

source:Vito leo

Today's KNOWLEDGE Share :Haldia Petrochemicals to start polycarbonate production

Today's KNOWLEDGE Share

India's First polycarbonate production at Haldia Petrochemicals

Haldia Petrochemicals is likely to invest over Rs 8,500 crore (apprx 1 billion Dollars) for polycarbonate production in Bengal. This petrochemical compound, not in production in India, would be an import substitute. Polycarbonate is mainly used in the automotive industry which continues to grow in the country.

Since all polycarbonate in India is imported and considering huge demand in India and have signed licence agreement with Lummus Technology for the the production of Polycarbonate,this will bring more domestic product manufacturers to come forward to start the production of various products based out of polycarbonate.

source:Times of India

Today's KNOWLEDGE Share : CARBON FIBER ADVANCEMENTS

Today's KNOWLEDGE Share

CARBON FIBER ADVANCEMENTS

In the early 1970s, it was discovered that heating pitch (petroleum or coal based) would produce a high carbon organic precursor that could be used to produce carbon fibers. Pitch-based carbon fibers deliver superior modulus and thermal conductivity but come up short in tensile strength and compression strength as compared to PAN-based carbon fiber.

Continuing research and development on these novel carbon fiber materials in the years that followed led to the innovations that we see today. Carbon fibers from all three precursor types are commercially available today but PAN dominates with well over 90% of carbon fibers being produced from this precursor.

source:Hexcel-Tom Haulik

Today's KNOWLEDGE Share :Thermoplastic polyurethane (TPU) 3D PRINTED LATTICE STRUCTURE

Today's KNOWLEDGE Share

MTDL used TPU lattice structures to create a compressible, tactile experience on this handheld device. One of the primary benefits of lattice structures is their ability to reduce material usage while maintaining mechanical integrity. By carefully designing the geometry of the lattice, we can optimize for load distribution, shock absorption, and even thermal management. This leads to significant weight reduction, a crucial factor in many applications and industries.

One of the most popular materials is thermoplastic polyurethane (TPU), a flexible and durable polymer known for its elasticity and impact resistance. TPU is particularly useful in applications requiring cushioning, such as protective gear, footwear, and soft robotic components.

The future of 3D printed lattice structures looks promising as advancements in materials and printing technologies continue to evolve. With ongoing research in bioresorbable materials, customized medical implants could become even more effective. Additionally, improvements in multi-material printing may allow for functionally graded structures that optimize performance in ways previously unimaginable. As additive manufacturing becomes more accessible, lattice structures will likely play a critical role in shaping the next generation of lightweight, high-performance products.

see this video: https://lnkd.in/gRn8Ti_7

source:MTDL

Avient unveils shelf-life extender and oxygen scavenging additive for PET packaging

Avient Corporation, an innovator of materials solutions, announces the launch of ColorMatrix™ Amosorb™ 4020L, an advanced shelf life extender oxygen scavenging additive produced specifically for polyethylene terephthalate (PET) bottle packaging. This new additive offers brand owners and converters a cost-effective solution to enhance the shelf life and recyclability of their PET bottles.

ColorMatrix Amosorb 4020L is developed to provide long-lasting shelf life performance, attractive bottle aesthetics, and outstanding recyclability. This non-nylon-based additive is compatible with recycled PET (rPET), making it an excellent option for brands looking to incorporate higher levels of recycled material (up to 100%) in their packaging.

"We are thrilled to introduce ColorMatrix Amosorb 4020L to the market," said Dr. Antonello Decortes, Global Product Manager at Avient Corporation. "This new additive technology represents a significant advancement in our commitment to offer extended protection against food spoilage in PET bottle applications. By also providing exceptional bottle clarity and recyclability, we are helping our customers meet market expectations and achieve their sustainability goals while reducing environmental impact."

This new oxygen scavenging additive is created for long-shelf life packaging applications such as condiments, sauces, juices, and beverages, including certain alcoholic drinks. It can be used at a wide range of dosage levels, providing flexibility to achieve the desired shelf life requirements.

Avient Corporation is dedicated to compliance with applicable regulatory requirements for product safety. ColorMatrix Amosorb 4020L meets direct food contact regulatory requirements in major markets.

source:Avient Corporation

Today's KNOWLEDGE Share : CARBON FIBER

Today's KNOWLEDGE Share

CARBON FIBER HISTORY:

Commercially available carbon fibers are based on one of three precursor materials --> rayon, PAN (polyacrylonitrile) and pitch. Early research in each of these carbon fiber types dates back to the late 1950s. Rayon, converted into a carbon fiber, was found to deliver the strongest and stiffest material for its weight that had ever been produced.

By 1963, Curry Ford and Charles Mitchell were granted a patent for making fibers and cloths by heat treating rayon to temperatures up to 3000 °C. These were the strongest carbon fibers commercially produced to date and led to the entry of carbon fibers into the “advanced composites” industry.

Research in converting more efficient precursors was occurring simultaneously in both Japan and the U.K. Akio Shindo of the Government Industrial Research Institute in Osaka, Japan made fibers in his lab with a modulus of more than 140 GPa, about three times that of the rayon-based fibers produced in the U.S.

In 1963, scientists in the U.K. also patented the process for producing even higher modulus PAN-based carbon fibers. The secret behind these quickly improving carbon fibers was the access to pure PAN which is the polymeric backbone that provided an excellent yield after processing.

source:Tom Haulik-HEXCEL

Today's KNOWLEDGE Share:Toray launches IR reflecting polyester film for windows

Today's KNOWLEDGE Share

Toray Launches a 50-Micrometer-Thick Version of PICASUS Nano-Multilayer Window Film Boosting Heat Shielding by 40%

Toray Industries, Inc., today announced that it has launched a 50-micrometer-thick version of PICASUS™ IR (see note 1) film for windows. This nano-multilayer film delivers exceptional transparency and heat shielding.

A push for energy-saving solutions and rising summer temperatures have boosted demand for high-performance heat-shielding window films. Demand is particularly robust for films delivering superior heat shielding and high transparency, as they preserve the aesthetic appearances of buildings and views within rooms while ensuring clear visibility for automobiles.

Toray refined its proprietary nano-multilayer technology, which can layer hundreds to thousands of ultra-thin polymer layers, to develop PICASUS™ IR, and deployed it for factory-installed automotive front windshields and sunroofs.

Toray developed a 50-micrometer film type for PICASUS™ IR for aftermarket building and vehicle applications. This 50-micrometer standard type offers significantly better transparency and heat shielding than conventional heat-shielding window films. Furthermore, the nano-multiple polymer layers deliver exceptional adhesion between each layer, making it easier to rework during installation than commercial products with the same level of heat shielding.

To meet the demands for improved heat shielding performance, Toray is expanding the lineup with a high heat insulation type that maintains high transparency while enhancing heat shielding by 40% compared to the standard type. (note 2) Customer evaluations of this high heat shielding type are also becoming more prominent.

Comparisons of standard and high heat shielding films as stated in the picture.

PICASUS™ IR applications encompass diverse new and existing buildings. This film also matches the high transparency standards of automotive windshields and provides excellent radio wave transparency, overcoming 5G communication issues associated with some metal sputtering technologies, thus ensuring driver safety and comfort.

Toray will keep leveraging its core technologies of synthetic organic and polymer chemistry, biotechnology, and nanotechnology to pursue R&D into groundbreaking materials that can transform the world in keeping with its enduring commitment to delivering new value and contributing to social progress.

Notes

1. PICASUS™ is the collective name for polyester films that leverage Toray’s proprietary nano-multilayer technology. The PICASUS lineup includes metallic luster films that uniformly interfere with and reflect light from visible to near-infrared rays, films that can cut blue light from displays without coloring them, and dichroic films that selectively reflect specific colors.

2. Toray evaluated heat shielding with the Total Solar Energy Rejected index, which measures the film’s ability to block the sun’s radiation.

source:Toray