polyurethane

Scientists from the University of Bath in the UK have developed a sustainable polymer using xylose, a sugar found in wood.

The new polymer is a member of the polyether family. It could be used in a variety of applications, including being a building block for polyurethane, used for example in mattresses and shoe soles. It could also be a bio-derived alternative to polyethylene glycol, a chemical widely used in biomedicine, or in polyethylene oxide, which is sometimes used as an electrolyte in batteries.

Xylose, also known as wood sugar, is one of the most abundant carbohydrates on earth, second only to glucose. Apart from comprising 5-20% of hardwoods, xylose is a major component of straw, corncobs, and many other plant materials.

The new polymer could reduce reliance on crude oil products and its properties can be easily controlled to make the material flexible or crystalline. Added functionality could be added to it by binding other chemical groups such as fluorescent probes or dyes to the sugar molecule for biological or chemical sensing applications.

Tweaking the physical and chemical properties of bio-derived polymers has previously been a very difficult thing to do. The Bath researchers discovered that combining two mirror-image chemical forms of xylose results in a stronger and more adaptable material. They have filed a patent for their technology and are seeking industrial collaborators for further development.

The reliance of plastics and polymers on fossil fuels is a major problem. Bio-derived polymers, such as this new one, are an important part of the effort to make plastics sustainable.

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Scientists make sustainable polymer from sugars in wood

Photo, posted January 25, 2017, courtesy of Keith Double via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Thermoset plastics are ones that contain polymers that cross-link together during the curing process to form an irreversible chemical bond. This improves the material’s mechanical properties, provides chemical resistance, heat resistance, and structural integrity. Thermosets include epoxies, polyurethanes, and rubber used for tires. The big problem with thermosets is that they cannot be easily recycled or broken down after use.

Seventy-five percent of all plastics are thermoplastics, which can be recycled by heating them until they become liquid and can then be remolded. Thermoset plastics, on the other hand, have such strong chemical bonds that they simply will not melt. They will typically burn before they can be remolded.

Chemists at MIT have recently developed a way to modify thermoset plastics with a chemical linker that makes them much easier to break down, but still retain the mechanical properties that make them so useful.

In a study published in Nature, the researchers produced a degradable version of a thermoset plastic called pDCPD. They then broke the plastic down into a powder and were able to use the powder to create more pDCPD. The paper also proposed a theoretical model that suggests that their approach could be used for a wide range of other plastics and polymers, including rubber.

By adding a chemical called a silyl ether monomer to the liquid precursors that from pDCPD plastic, they found that the resultant material retained its mechanical strength but can be broken down into a soluble powder upon exposure to fluoride ions.

Using this approach with other thermoset materials, the researchers believe it will be possible to create recyclable versions of many of the toughest plastic materials.

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Chemists make tough plastics recyclable

Photo, posted September 1, 2019, courtesy of Luke McKernan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Sustainable Polymer From Wood | Earth Wise

Scientists from the University of Bath in the UK have developed a sustainable polymer using xylose, a sugar found in wood.

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Recycling Tough Plastics | Earth Wise

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