Chinese and U.S. scientists jointly develop new technologies that can dramatically increase the performance of biodegradable bioplastics

[Chinese Packaging Network News] Chinese and American scientists have jointly developed a new technology that can significantly increase the heat and water resistance of biodegradable bioplastics, polylactic acid, reduce commercial production costs and reduce pollution.

A press release issued by the University of Nebraska-Lincoln in the United States said that the technology was jointly developed by the school and researchers from Jiangnan University in China. The core step was to heat the polylactic acid fiber to approximately 200 degrees Celsius and allow it to cool slowly. In this way, two kinds of polylactic acid molecules are intertwined and complexed to obtain a product with higher heat and water resistance.

The research group reported in the Swiss Journal of Chemical Engineering that the heat treatment method can make the performance of bioplastics comparable to that of petrochemical plastics, and is simpler and greener than the existing technology.

Polylactic acid, also known as corn plastic, is a high molecular compound made from starch-rich agricultural products such as corn, which can be naturally degraded and is a promising green plastic. However, its application range is limited due to poor heat and water resistance.

There are two forms of polylactic acid that are mirror images of each other. Previous studies have found that plastics, which consist mainly of one molecule, have poor performance. If the two molecules are mixed and interlaced in suitable proportions, the performance can be improved. Some existing technologies can achieve such "stereocomplexation", but the process is complicated, the cost is high, and harmful solvents or additives need to be used. At present, polylactic acid fibers prepared by intertwining and intertwining two kinds of molecules by heat treatment have a melting point 38 degrees Celsius higher than that of a polylactic acid composed of one molecule and are still well maintained in a water-containing environment having a temperature exceeding 120 degrees Celsius. The structure and strength meet the application requirements of the textile industry.

The researchers said that they have clarified the relationship between the heat treatment temperature and the degree of stereocomplexation and the strength of the finished plastic fiber. They have achieved small-scale continuous production in the laboratory and are seeking to use the technology in existing industrial production processes.