Monday, March 4, 2024

New Bilayer Adhesive Hemostat Enhances Wound Healing

Pohang University of Science and Technology (POSTECH) researchers have developed a bilayer nanofiber membrane hemostat using natural proteins derived from mussels and silkworm cocoons.

The research team was led by Professor Hyung Joon Cha (Department of Chemical Engineering and the School of Convergence Science and Technology) and Dr. Jaeyun Lee (Department of Chemical Engineering) at Pohang University of Science and Technology (POSTECH), Professor Kye Il Joo (Department of Chemical Engineering and Materials Science) at Ewha Womans University, and Dr. Jong Won Rhie at Seoul St. Mary's Hospital of the College of Medicine at the Catholic University of Korea.


Using Mussel and Silkworm Proteins:

Conventional hemostatic agents such as gauze or medical bands are limited to application on the surface of the skin. Although there are certain materials that naturally degrade within the body like fibrin glue and collagen sponges, they necessitate proteins sourced from humans or animals, making them considerably expensive. Moreover, existing hemostatic materials lack consistent adherence to bleeding sites and are prone to infection from external contaminants.

In response, the researchers developed a bilayer adhesive hemostat utilizing mussel adhesive proteins that exhibit strong tissue adhesion underwater and silk fibroin extracted from silkworm cocoons. In the research, mussel adhesive proteins demonstrated excellent hemostatic effects including platelet activation. The researchers employed methanol vapor to modify the secondary structure of silkworm silk proteins, resulting in a nanofiber membrane with a hydrophobic outer surface.


In light of this, the team engineered a hemostatic agent featuring an inner layer with mussel adhesion proteins for wound adhesion and an outer protective layer entirely composed of silkworm silk proteins. Through animal experiments, the hemostatic agent demonstrated rapid acceleration of tissue adhesion and hemostasis in bleeding wounds, effectively preventing the infiltration of water containing infectious agents such as bacteria. Using two proteins that are both highly biocompatible and biodegradable, the researchers have introduced a novel hemostatic agent capable of clotting blood and providing defense against infection.


Stops Bleeding and Preventing Infection:

We have validated the exceptional hemostatic performance of a multifunctional topical adhesive hemostatic agent that is derived from nature and is based on degradable proteins in the human body.” He added, “We will continue further research to assess its applicability in real-world patient care or surgical settings.”


The research was conducted with support from the Marine BioMaterials Research Center Program of the Ministry of Oceans and Fisheries and the Mid-Career Research Program of the National Research Foundation of Korea.


Source: Pohang University of Science and Technology/specialchem

Today's KNOWLEDGE Share:Coating on moldings

Today's KNOWLEDGE Share

If you browse through the documentation of mold coating suppliers (PVD, WS2, others) they all claim better flow (i.e. lower pressure to fill) after coating the mold with just a few microns of their coating (typically a metal oxide, salt, or some other complex).


These layers do impart lubricity indeed, which is great to help ejection of the molded part.

But in Injection Molding there is no slip against the wall. Actually if/when you get some, you invariably end up with a surface defect !

So improved lubricity, as claimed by suppliers, DOES NOT explain better flow.


What is most probably happening is that the added layer, which is not "metallic" has always a lower Thermal Effusivity.

Effusivity is the material property that controls interfacial temperature.

So what we really have here is a slightly thinner frozen skin resulting from a somewhat higher interfacial temperature between plastic and coated steel. In a flat flow, effective available thickness for flow has a quadratic effect on pressure drop. For a runner/gate (cylinder) it is even a cubic dependence.

So the smallest reduction in the frozen layer, especially for thin cavities, can immediately explain the observed 5-10 % decrease in pressure drop (or, conversely, increase in flow length).


source:Vito leo

Thursday, February 29, 2024

Today's KNOWLEDGE Share: Geometric lattice cores!

Today's KNOWLEDGE Share

Let's dive into the world of geometric lattice cores! 

When talking about geometric lattice cores, most people think about a core with hexagon shaped cells, which is the basic and most common cellular honeycomb configuration. However, we have other options currently available on the market, such as Flex-Core, Ox-Core and Double-Flex to name a few! 


But how to select between them? 

The Flex-Core cell configuration provides for exceptional formability in compound curvatures with reduced anticlastic curvature and without buckling the cell walls. Curvatures of very tight radii are easily formed. When formed into tight radii, Flex-Core provides higher shear strengths than a comparable hexagonal core of equivalent density. 


The “OX” configuration is a hexagonal honeycomb that has been over-expanded in the “W” direction, providing a rectangular cell configuration that facilitates curving or forming in the “L” direction. The OX process increases “W” shear properties and decreases “L” shear properties when compared to hexagonal honeycomb. 


Double-Flex is a unique large cell Aluminum Flex-Core with excellent formability and high specific compression properties. Double-Flex formability is similar to standard Flex-Core. 


Source: Hexcel/ #managingcomposites #thenativelab


#composites

Syensqo expands its bio-based portfolio with a new MTM® epoxy prepreg

Syensqo, previously part of Solvay Group, has developed a new version of its flagship MTM® 49-3 resin that contains 30% bio-sourced monomers. The new product variant complements the portfolio of the company’s MTM® advanced prepregs and targets structural automotive applications, including body panels, chassis components and spoilers.


“Our new bio-based MTM® 49-3 will help OEMs and Tiers to reduce fossil depletion and meet their carbon neutrality goals, while ensuring the same high levels of quality, processability and mechanical performance as its original counterpart,” states Greg Kelly, Head of Composite Product Management at Syensqo.


Just like the incumbent material, Syensqo’s new bio-based MTM® 49-3 has a dry glass transition temperature (Tg) of 190°C, and it exhibits enhanced toughness for superior impact resistance versus competitive thermoset prepregs. Thanks to its high strength-to-weight ratio, it can yield component mass savings of up to 40% over metals. The product is compatible with autoclave and press-conversion processes and achieves curing at 135°C within 60 minutes. In addition, it has been designed for operator safety, and is free from carcinogens, mutagens or reproductive toxins.


Syensqo will officially introduce the bio-based MTM® 49-3 to the market at JEC World 2024 from March 05 to 07 at booth K58 in hall 5.


source:www.syensqo.com/jeccomposites.com

Wednesday, February 28, 2024

Mitsubishi Chemical to Discontinue MMA, Acrylonitrile Production at Hiroshima Plant

The Mitsubishi Chemical Group (MCG Group) announces to discontinue MMA monomer production by the ACH process. They are halting the production of acrylonitrile and acrylonitrile derivatives at the Mitsubishi Chemical Hiroshima Plant (Otake City, Hiroshima Prefecture).


Following the discontinuance of production, the MCG Group will also withdraw from the chelating agent and acetonitrile businesses.


Reason for Discontinuance of Production:

The MCG Group produces MMA monomers by three different methods (ACH process, C4 process, and Alpha technology) at its MMA monomer production bases around the world. It also enhances the supply chain in response to the demand-supply situation and trends with regard to materials used for production.


For the acrylonitrile business, the MCG Group has two production bases in Japan. These bases supply acrylonitrile and acrylonitrile derivatives. They also supply a byproduct from the acrylonitrile production process as a material for MMA production by the ACH process.


The company has taken the decision to enhance the Group’s competitiveness in the MMA and acrylonitrile businesses. It will also optimize the supply system.


However, the MCG Group will continue to produce MMA monomers produced by the C4 process at the Hiroshima Plant. It will also continue production of acrylonitrile and sodium glycinate at the Okayama Plant and acrylamide at the Kanto Plant.


Products to be discontinued at the Hiroshima Plant:

MMA monomers produced by the ACH method

Acrylonitrile

Acrylonitrile derivatives (chelating agent, acetonitrile and ammonium sulfate)


Production of the products listed above will be discontinued in July 2024.


Source: Mitsubishi Chemical Group/spcialchem.com

Today's KNOWLEDGE Share:The history of fiberglass!

Today's KNOWLEDGE Share

The history of fiberglass! 


The use of fiberglass dates back to 1836 when Ignace Dubus-Bonnel received the world’s first patent on a method of making them. At the time, fiberglass was hard to make thin enough to be completely flexible, and no reliable method of mass production existed. 


These problems would only be solved in 1932 by Dale Kleist, a graduate student who was working part-time at Owens-Illinois as a researcher. The company wanted to make glass blocks for architectural use, and its researchers were looking for a way to seal the two halves of a block together so that moisture couldn’t get inside. 


He decided to try a metal-spraying gun with molten glass instead of bronze and discovered that it created a shower of ultrafine, thread-like glass fibers. Owens-Illinois immediately recognized that this was an excellent way to make glass wool for insulation and that it might be adaptable for other applications. 


Four years and the researchers were turning out individual strands long and flexible enough to be woven into cloth. The cloth was remarkably strong, and it could be cut and folded just like ordinary fabrics. 


Bibliographical Reference:

The Fiberglass Story, written by Michael Lamm

source:managingcomposites


Nokian Tyres Signs Agreement with Tire Recycling JV for Recovered Carbon Black

Nokian Tyres has made a long-term purchase agreement with a tire recycling joint venture. The agreement will help Nokian Tyres reach one of its key sustainability targets.


It will help to increase the share of recycled and renewable raw materials in tires to 50 percent by 2030. Nokian Tyres started to use recovered carbon black in a commercial product line in 2022. The long-term purchase agreement enables its increased utilization in tires accelerating circularity and sustainability in the tire industry.


Reducing the Use of Virgin Raw Materials:

The joint venture, formed by e.g. Antin Infrastructure Partners and Scandinavian Enviro Systems, plans to establish end-of-life tires recycling plants across Europe.


It will have a total capacity to recycle up to one million tons of end-of-life tires annually by 2030. The first plant, located in Sweden, is expected to be fully operational by 2025. The deliveries for Nokian Tyres will begin in 2026.


Carbon black is used as a reinforcing filler in tires to enhance their physical properties, such as strength. As virgin carbon blacks are fossil-based, replacing them partly with recovered carbon black decreases the environmental burden of tires’ raw materials. It also accelerates the circular economy of the tire industry, as the recovered carbon black is made with pyrolysis from end-of-life tires.


“The use of recovered carbon black has several sustainability-related benefits. It reduces the use of virgin raw materials and increases the share of recycled ones. The emissions from manufacturing recovered carbon black are over 90 percent lower than those from virgin carbon blacks. On a larger scale, use of recovered carbon black also increases circularity and sustainability in the tire industry,” says Juha Hietalahti, VP, Procurement at Nokian Tyres.


“When introducing new raw materials in tires, one of the most demanding tasks is to find the right balance between raw material selection and tire properties. The use of recycled or renewable materials must not impair a tire’s safety characteristics. The recovered carbon black that we will receive with this agreement is an important step in creating even more sustainable premium tires that provide safety in all driving conditions,” Hietalahti says.


Source: Nokian Tyres/specialchem news

Michelin ResiCare launches two new alternatives to phenolic resins

Michelin ResiCare, a brand of the #MichelinGroup , announces the commercial launch of #Resi4 carbon/carbon and Resi4 ablation, two innovati...