Today's KNOWLEDGE Share: Composite Rebar for Construction Sector

Today's KNOWLEDGE Share

Arkema and Sireg Geotech Develop Bendable Composite Rebar for Construction Sector 

Arkema and Sireg Geotech have developed the world's first bendable composite rebar. It provides an innovative alternative to traditional steel reinforcement. It is based on Arkema's Elium® resin. Sireg's Glasspree® TP bars represent a breakthrough for the construction sector.

Double the Tensile Strength of Steel:

Sireg's fiberglass bars using the Elium® thermoplastic resin have double the tensile strength of steel. They stand out by their remarkable light weight (75% lighter than steel), their corrosion-proof property and their chemical resistance. They show dimensional stability in the event of extreme thermal changes and are also fully recyclable. They contribute to the energy efficiency of structures. Also, they significantly reduce the carbon footprint of maintenance activities.

The Elium® thermoplastic resin ensures a major gain in productivity as well as greater flexibility for the supply of composite reinforcement, thus improving the overall profitability of construction projects. The range of applications of Sireg's Glasspree® TP bars is huge. It can be used for construction, maintenance, repair of buildings, bridges, tunnels, as well as marine and coastal structures, which demonstrates their adaptability.

“Glasspree® TP bars were developed through cooperation between Sireg and Arkema. They represent an innovation in the reinforcement of concrete structures as well as a new benchmark in terms of safety, reliability, and sustainability,” says Sonja Blanc, CEO Sireg.

For bridges these materials ensure an estimated service life of twice that of steel (i.e. 100 years), lighter weight, and superior corrosion resistance in a saline environment, lower lifecycle costs, and a lower impact on the environment.

Source: Arkema/omnexus.specialchem

Today's KNOWLEDGE Share : Bio-based acrylonitrile

Today's KNOWLEDGE Share

Bio-based acrylonitrile for carbon fiber manufacture!

"As part of its research with bio-based ACN, Southern Research conducted a life cycle assessment (LCA), comparing biomass-to-ACN manufacture to petroleum-to-ACN manufacture. Results said bio-based ACN manufacture offers a carbon footprint of -1.57 pounds equivalent CO2 per pound of finished product, compared to 3.5 pounds equivalent CO2 per pound of finished product for petroleum-based ACN manufacture. In short, the bio-based feedstock allows for a process that conserves carbon emissions.

"Regarding cost, Southern Research’s process is sensitive to the purity of the sugars feedstock, and the higher the feedstock quality, the more expensive it is. When last spoke to Southern Research, it was getting ready to commission a small-scale production plant and looking for carbon fiber manufacturers willing to assess the quality of its ACN.

source:managingcomposites

Spontaneous curvature the key to shape-shifting nanomaterials

Inspired by nature, nanotechnology researchers have identified ‘spontaneous curvature’ as the key factor determining how ultra-thin, artificial materials can transform into useful tubes, twists and helices.

Greater understanding of this process - which mimics how some seed pods open in nature - could unlock an array of new chiral materials that are 1,000 times thinner than a human hair, with the potential to improve the design of optical, electronic and mechanical devices.

Chiral shapes are structures that cannot be superimposed on their mirror image, much like how your left hand is a mirror image of your right hand but cannot fit perfectly on top of it.Spontaneous curvature induced by tiny molecules can be used to change the shape of thin nanocrystals, influenced by the crystal width, thickness, and symmetry.

Shapeshifting at the nanoscale:

Imagine a piece of paper that, when dipped into a solution, twists or curls into a spiral without any external force. This is akin to what happens at the nanoscale with certain thin materials.Researchers have discovered that when certain types of semiconducting nanoplatelets - extremely thin, flat crystals - are coated with a layer of organic molecules called ligands, they curl into complex shapes, including tubes, twists and helices. This transformation is driven by the different forces the ligands apply to the top and bottom surfaces of the nanoplatelets.

From nature’s design to nanoscale innovation:

The inspiration for this research stems from observing natural phenomena where helical structures are prevalent, from the DNA in our cells to the spontaneous twisting of seed pods. These structures possess unique properties that are highly desirable in materials science for their potential applications in mechanics, electronics, and optics.

Nanoplatelets, with their ability to form helical structures, and exceptional optical properties due to quantum confinement, stand out as a prime candidate for creating new materials with specific characteristics. These could include materials that selectively reflect light, conduct electricity in novel ways, or have unique mechanical properties.

A framework for future technologies:

The implications of this research are considerable. By providing a framework to understand and control the shape of nanoplatelets, scientists have a new tool to design materials with precisely-tuned properties for use in technologies ranging from advanced electronics to responsive, smart materials.

For instance, nanoplatelets could be engineered to change shape in response to environmental conditions, such as temperature or light, paving the way for materials that adapt and respond to their surroundings. This could lead to breakthroughs in creating more efficient sensors.

Moreover, the study hints at the possibility of creating materials that can switch between different shapes with minimal energy input, a feature that could be exploited in developing new forms of actuators or switches at the nanoscale.

source:https://www.pnas.org/doi/abs/10.1073/pnas.2316299121/nanotechnolgyworld

Today's KNOWLEDGE Share:South Korea solved the food waste problem.

Today's KNOWLEDGE Share

South Korea solved the food waste problem.

Zero percent of their food waste ends up in landfills.

In 2005, the country actually banned dumping food waste in landfills.

And as many know, landfills are the worst place for food waste to end up.It not only releases methane when it ends up in landfills.But it also becomes a lost resource for another parts of the economy.

South Korea residents separate food scraps from their recycling and other waste.The food waste then gets turned into animal feed, composted or used to heat homes.And residents are billed according to weight of food waste discarded, around $3-6/month.

The program, albeit successful, still costs the government $600 million per year.

A small price to pay to redirect wasted resources elsewhere, be responsible for the true costs of food, and being accountable for the environmental impacts of food waste.

We don't need to produce more food.We need to fix our resource streams.

Some of the solutions we are looking for exist in the food waste streams.South Korea proves our point.

source:Mitch Hinrichs

#circulareconomy

Study Finds Microplastics in Every Tested Human Placenta

University of New Mexico Health Sciences researchers have used a new analytical tool to measure the microplastics present in human placentas.

A team led by Matthew Campen, PhD, Regents’ professor in the UNM Department of Pharmaceutical Sciences, reported finding microplastics in all 62 of the placenta samples tested, with concentrations ranging from 6.5 to 790 micrograms per gram of tissue. The study was published in the journal Toxicological Sciences.

Although those numbers may seem small (a microgram is a millionth of a gram), Campen is worried about the health effects of a steadily rising volume of microplastics in the environment.

Used Pyrolysis to Catch Gas Emissions of Different Plastics

“If we’re seeing effects on placentas, then all mammalian life on this planet could be impacted. That’s not good,” says Matthew Campen, PhD, Regents’ professor in the UNM Department of Pharmaceutical Sciences.

For toxicologists, “dose makes the poison,” he said. “If the dose keeps going up, we start to worry. If we’re seeing effects on placentas, then all mammalian life on this planet could be impacted. That’s not good.”

In the study, Campen and his team, partnering with colleagues at the Baylor College of Medicine and Oklahoma State University, analyzed donated placenta tissue. In a process called saponification, they chemically treated the samples to “digest” the fat and proteins into a kind of soap.

They then spun each sample in an ultracentrifuge, leaving a small plastic clump at the bottom of a tube. Next, using a technique called pyrolysis, they placed the plastic pellet in a metal cup and heated it to 600 degrees Celsius. Then they captured gas emissions as different types of plastic combusted at specific temperatures.

“The gas emission goes into a mass spectrometer and gives you a specific fingerprint,” Campen said. “It’s really cool.”

Polyethylene was the Most Abundant Polymer Found:

The researchers found the most abundant polymer in placental tissue was polyethylene, which is used to make plastic bags and bottles. It accounted for 54% of the total plastics. Polyvinyl chloride and nylon each represented about 10% of the total, with the remainder consisting of nine other polymers.

Marcus Garcia, PharmD, a postdoctoral fellow in Campen’s lab, said that until now, it has been difficult to quantify how much microplastic is present in human tissue. Typically, researchers would simply count the number of particles visible under a microscope, even though some particles are too small to be seen.

Source: University of New Mexico Health Sciences/specialchem

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