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Method for High-Yield Chemical Recycling of Plastic Waste

Professor Matthew Conley from the University of California, Riverside has discovered that catalysts used to generate polyolefin plastics also perform well in hydrotreatment reactions of plastic waste. This method works by treating plastic materials with known catalysts at 200⁰C to degrade  polymers into smaller alkanes in the presence of hydrogen. This technology is advantageous compared to existing methods since it does not require high temperatures​, has a relatively high yield (+80%)​, and can be applied to a variety of plastics to generate a feedstock of smaller polymers and monomers for further processing.  

Liquid Conductive Self-Coacervates Via Associative Phase Separation In Water

Water-based viscoelastic liquids that are highly enriched in polyelectrolytes are attractive for a number of applications including low-surface tension materials useful in industries such as cosmetics and food science. In nature, polyelectrolyte-based viscoelastic liquids are used by organisms as underwater adhesives in salt-water environments. Such viscoelastic liquids, called coacervates, typically form with electronically inactive polyelectrolyte.An electronically active coacervate could enable such applications such as electrically conducting underwater adhesives and water-based photoactive viscoelastic pastes. This could be useful for environmentally benign soldering materials, sensing, color-sensitive coatings and the enhancemeent of photochemically driven chemical reactions. A research team at UC Santa Cruz has designed a series of conjugated polyelectrolytes (CPEs) that can form electronically active liquid coacervate phases. 

Upcycling Waste Polyvinyl Chloride (PVC) To Prepare Value-Added Dienes

Making productive use of PVC waste is a challenge. Mechanical recycling is difficult because different PVC products each contain different blends of plasticizers, stabilizers, and other additives; combining these additives leads to diminished mechanical properties.Meanwhile, incineration of PVC is an issue because it produces corrosive HCl and toxic chlorinated dioxins, a class of persistent organic pollutants. Changing regulations also present an issue: harmful plasticizers such as diethylhexylphthalate (DEHP) still present in legacy PVC products are now banned in newly made (or newly recycled) PVC in the EU. In the US, DEHP is restricted in childcare articles and food packaging. Vinyloop®, a plant designed to recycle PVC from mixed waste by selective dissolution/precipitation, was shut down in 2018 due to its inability to remove phthalates.  Lead stabilizers found in legacy PVC products are similarly banned in new products, complicating recycling. Chemical recycling and upcycling of polymers is a growing field of interest with the goal of creating a circular economy. Breaking down a polymer into monomer or other useful small molecules allows purification of the products and avoids the downcycling phenomenon seen in mechanical recycling. Polymers with labile ester or amide bonds in their backbone are more amenable to this treatment than polymers with an all-carbon backbone. For instance, polyethylene terephthalate and polyurethane can both be depolymerized by hydrolysis, alcoholysis, or aminolysis; the monomers or short oligomers obtained can be repolymerized to form the original polymer or other high-performance polymers. Polymers with all-carbon backbones are more challenging to controllably cleave, but many methods have been developed to break down polyethylene, polypropylene, and polystyrene into light hydrocarbon fuels, benzene derivatives, or H2 gas. However, even small amounts of PVC can contaminate these reactions and deactivate the catalyst, requiring PVC to be separated out first.  Chemical upcycling of PVC is underdeveloped compared to that of other polymers, despite the fact that it is the third-most produced plastic in the world. Most PVC degradation procedures explored have been carried out at high temperatures (200-900 oC) and focus on pyrolysis to small hydrocarbons or oxidation to carboxylic acids. Pyrolysis of PVC is complicated by the release of HCl, which can corrode the equipment and deactivate catalysts. Solutions to this include pre-treatment with base, or pyrolysis in the presence of base or bio-waste. In some cases, products are a mixture of acetone, benzene, and other aromatics. In other cases, alkanes or syngas (CO and H2) are produced. There remains a need for new approaches to chemically break down PVC. Expanding the toolbox of reactions that can controllably degrade PVC will allow a wider range of products to be made, and bring the world closer to the goal of harvesting plastic waste as a resource. 

A Bio-Based Manufacturing Process To Create Foam Using Chitin Sourced From Shellfish Waste

A bio-based closed-cell foam created using chitin derived from shellfish waste. Chitin is the second most abundant polysaccharide after cellulose and acts as the structural component of the exoskeleton of arthropods. Chitin has mechanical properties that can be processed into a foam. Such a foam can be used for biodegradeable packaging as well as other uses. 

Bio-mimetic Wetness Device and Method

In 2019, the Food and Agriculture Organization of the United Nations estimated that between 20 to 40 percent of global crop production are lost to plant diseases and pests annually, with plant diseases costing the global economy roughly $220B each year. Disease-warning systems are currently being used by growers to preemptively mitigate destructive events using chemical treatment or biological management. Meteorological factors including rainfall, humidity, and air temperature are all considered in these systems, but the measurement of leaf wetness duration (LWD) is important to its governing role in infection processes for many fungal pathogens. The longer a leaf stays wet, the higher the risk that disease will develop, because many plant pathogen propagules require several hours of continuous moisture to germinate and initiate infection The current gold standard to measuring LWD is using the capacitive leaf wetness sensor (LWS). The LWS functions by measuring a change in the capacitance seen at its surface which then yields an output signal that changes according to its surface wetness. Commercial leaf wetness sensors estimate the amount of surface water and leaf wetness duration by measuring the change in capacitance of a surface that accumulates condensed water. However, the one-size-fits-all commercial sensors do not accurately reflect the variation in leaf traits (particular shape, texture, and hydrophobicity) these traits strongly affect surface wettability (hydrophilicity) and vary widely among plant species.

Low-Cost Synthesis of High Performance Polyurethanes

Professor Charles Cai from the University of California, Riverside has developed a method to produce a high-performance, renewable polyurethane material made from biomass lignin for use as an adhesive, resin, coating, or plastic. In this method, diols were introduced to realize faster and complete dissolution of technical lignins in volatile organic solvents, which improve lignin miscibility with other components and its dispersion in the PU materials. This technology is advantageous because it improves the economic viability of lignocellulosic biorefinery, can replace petroleum-based polyols in commercial polyurethanes products to reduce carbon footprint, and, as a natural UV-block, lignin reduces the UV aging of PU materials.   Fig 1: The UCR method to produce polyurethane material from biomass lignin.  

Medical Device: Electrode for Wearable Point-of-Care Health Monitoring

Researchers at the University of California, Irvine have fabricated a flexible and unobtrusive wearable electrode that can detect glucose at a very low limit of detection.In fact, the detection limits are the lowest ever reported for an enzyme-free sensor. This sensor is applicable for detecting glucose levels in saliva, sweat or tears, and can safely be used at home, especially by diabetic patients without the need to frequently draw blood.

Microchannel Polymer Heat Exchanger

Researchers at the University of California, Davis have developed a highly efficient microchannel polymer heat exchanger in a compact and lightweight design.

Synergistic Enzyme Mixtures to Realize Near-Complete Depolymerization in Blends

In this technology, the inventors introduce additives to purposely change the morphology of polycaprolactone (PCL) by increasing the bending and twisting of crystalline lamellae. These morphological changes immobilize chain-ends preferentially at the crystalline/amorphous interfaces and limit chain-end accessibility by the embedded processive enzyme. This chain end redistribution reduces the polymer-to-monomer conversion from >95% to less than 50%, causing formation of highly crystalline plastic pieces including microplastics. By synergizing both random chain scission and processive depolymerization, it is feasible to navigate morphological changes in polymer/additive blends and to achieve near complete depolymerization. The random scission enzymes in the amorphous domains create new chain ends that are subsequently bound and depolymerized by processive enzymes. Present studies further highlight the importance to consider host polymer morphological effects on the reactions catalyzed by embedded catalytic species.This is part of a patent family in compostable plastics.  

Fabricating Crystallinity Unique Carbon Nanowires (~5nm) with Ultrahigh Electrical Conductivity

UCI engineers have designed a new protocol for the synthesis of technology materials that uses electrospinning to draw polymers into ~5nm carbon nanowires.

Spray Coated Paint Based on Glass Bubbles for Buildings

Developing optical materials with a high solar reflectivity and high mid-infrared emissivity is important for coating the outdoor buildings. The authors proposed a spray coated paint based on glass bubbles which can be used to maintain the thermal environment of constructions.

2-D Polymer-Based Device for Serial X-Ray Crystallography

Researchers at the University of California, Davis have developed a single-use chip for the identification of protein crystals using X-ray based instruments.

Synthesis of Capsular Polysaccharides

Researchers at the University of California, Davis have developed a more cost effective and consistent method for producing capsular polysaccharides, a component of certain types of vaccines.

Optimizing Bipolar Membrane Interfaces to Catalyze Water Dissociation

Researchers at UCI have modified current commercial membranes to enhance efficiency of water dissociation at varying conditions for electrochemical technologies geared towards renewable fuel generation.

Method For Liquid-To-Solid Phase Separation Of Uranium And Uranyl Contaminant From Various Solutions

Researchers at UCI have developed a separation method for removing radioactive contaminants, specifically uranium contaminants, from liquid solutions.

Flow Chemistry Synthesis Of Diisocyanates From Algae Oil Derived Diacids

Isocyanates serve as important and versatile chemical intermediates in the manufacture of diverse products ranging from flexible and rigid polyurethane foams to agrochemicals and pharmaceuticals. The production of isocyanates today draws mainly from petrochemical raw materials, including benzene, toluene, propylene, and aniline, and they are produced industrially using phosgenation of alkyl or aromatic amines. This involves highly toxic phosgene and produces corrosive HCl, limiting synthetic applications.

A Phase-Changing Polymer Film for Broadband Smart Windows Applications

UCLA researchers in the Department of Materials Science and Engineering have developed an energy efficient smart window coating with wide light bandwidth and long cycle lifetimes.

Oxime Crosslinked Hydrogels To Prevent Postsurgical Cardiac Adhesions

Although a wide variety of hydrogels have been developed for a multitude of uses, various functional characteristics have been hard to capture in a controllable manner. A significant feature is the ability to ‘tune’ the gel so its gelling time can be controlled in a manner suitable to its application. In this disclosure, because the gel is both tunable and its composition allows it to bond to tissue, the inventors believe it can be used to address an unmet medical need – the formation of adhesions after cardiac surgery. Current methods used are either drug therapy or various physical barriers but their success is limited.

Ruthenium-Catalyzed Selective Oxidation Of Polyethylenes

Polyolefins currently constitute approximately half of all synthetic plastics produced worldwide.  Despite their low cost and excellent thermal and mechanical properties, polyolefins generally do not mix well with other materials, and this lack of compatibility limits their use in high-performance composites and as components of more sustainable plastics.  This invention incorporates low levels of polar functional groups into polyolefins which is a promising strategy to overcome this shortcoming.  

One-Pot Synthesis of Polyol from Algae Oil for Sustainable Polyurethanes

A large sector with potential for improvement is the polyurethane industry, which produces versatile polymers and foams for use in many commercial products. Production of these polymers is dependent on precursor polyols. Current production of industrial polyols is dominated by petroleum-derived polyethers, which is unsustainable and presents environmental hazards due to their poor degradation in the environment.

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