Plastarch Material (PSM) is a

biodegradable Biodegradation is the breakdown of organic matter by microorganisms, such as bacteria and fungi. It is generally assumed to be a natural process, which differentiates it from composting. Composting is a human-driven process in which biodegradati ...

thermoplastic A thermoplastic, or thermosoft plastic, is any plastic polymer material that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling. Most thermoplastics have a high molecular weight. The polymer chains associat ...

resin. It is composed of

starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diets ...

combined with several other biodegradable materials. The starch is

modified Modified may refer to: * ''Modified'' (album), the second full-length album by Save Ferris * Modified racing, or "Modifieds", an American automobile racing genre See also * Modification (disambiguation) * Modifier (disambiguation) Modifier may ...

in order to obtain heat-resistant properties, making PSM one of few

bioplastic Bioplastics are plastic materials produced from renewable biomass sources, such as vegetable fats and oils, corn starch, straw, woodchips, sawdust, recycled food waste, etc. Some bioplastics are obtained by processing directly from natural ...

s capable of withstanding high temperatures. PSM began to be commercially available in 2005. PSM is stable in the atmosphere, but biodegradable in compost, wet soil, fresh water, seawater, and activated sludge where microorganisms exist. It has a softening temperature of 257 °F (125 °C) and a melting temperature of 313 °F (156 °C). It is also

hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substance ...

. The material has to be dried in a material dryer at 150 °F (66 °C) for five hours or 180 °F (82 °C) for three hours. For injection molding and extrusion the barrel temperatures should be at 340° +/- 10 °F (171 °C) with the nozzle/die at 360 °F (182 °C). Due to how similar PSM is to other plastics (such as

polypropylene Polypropylene (PP), also known as polypropene, is a thermoplastic polymer used in a wide variety of applications. It is produced via chain-growth polymerization from the monomer propylene. Polypropylene belongs to the group of polyolefins an ...

and CPET), PSM can run on many existing thermoforming and injection molding lines. PSM is currently used for a wide variety of applications in the plastic market, such as food packaging and utensils, personal care items, plastic bags, temporary construction tubing, industrial foam packaging, industrial and agricultural film, window insulation, construction stakes, and horticulture planters. Since PSM is derived from a renewable resource (

corn starch Corn starch, maize starch, or cornflour (British English) is the starch derived from corn (maize) grain. The starch is obtained from the endosperm of the kernel. Corn starch is a common food ingredient, often used to thicken sauces or soup ...

), it has become an attractive alternative to petrochemical-derived products. Unlike plastic, PSM can also be disposed of through incineration, resulting in non-toxic smoke and a white residue which can be used as fertilizer. However, concerns have been expressed about the impact of such technologies on

food prices Food prices refer to the average price level for food across countries, regions and on a global scale. Food prices have an impact on producers and consumers of food. Price levels depend on the food production process, including food marketing a ...

Biodegradability concerns

Some PSM products - such as cutlery - contain a mix of PSM and plastics. These plastics prevent the PSM from degrading, making the entire product non-biodegradable.

References

{{reflist Polymer chemistry Thermoplastics Transparent materials