Made to Degrade (Even­tu­ally)

The main cause of mar­ine debris accu­mu­la­tion is the dump­ing of plastic waste into the oceans, as most plastic does not degrade when left in the envir­on­ment. Mar­ine bio­de­grad­able plastics have pre­vi­ously been developed in Japan, with PHBH (by Kaneka Cor­por­a­tion) and PBS (by Mit­subishi Chem­ic­al Cor­por­a­tion) cur­rently avail­able. How­ever, these are both cat­egor­ized as aliphat­ic poly­es­ters and are of poor qual­ity com­pared to con­ven­tion­al plastics, such as poly­ethyl­ene and polypro­pyl­ene, while being pro­du­cible only in low yields (approx­im­ately tens of thou­sands of tons per year com­pared to an annu­al glob­al pro­duc­tion of 300 mil­lion tons for con­ven­tion­al plastics) and at more than twice the cost of that of con­ven­tion­al plastics, all of which are factors that have lim­ited their use. Thus, there has been a strong demand for the devel­op­ment of a low-cost and mass-pro­du­cible mar­ine bio­de­grad­able plastic that can enable us to tackle the grow­ing prob­lem of mar­ine debris. A group of research­ers led by Asso­ci­ate Pro­fess­or Taka-Aki Asoh and Pro­fess­or Hiroshi Uyama of the Gradu­ate School of Engin­eer­ing, Osaka Uni­ver­sity, has, in col­lab­or­a­tion with Nihon Shok­uh­in Kako Co., com­bined the ubi­quit­ous bio­masses starch, the main com­pon­ent of the car­bo­hydrates found in corn, tubers, and roots such as pota­toes, and cel­lu­lose, the main com­pon­ent of plants and com­monly known as cot­ton fiber, to devel­op a mar­ine bio­de­grad­able plastic. Because this com­bin­a­tion was done using their unique tech­no­logy, the water-res­ist­ance of starch improved sig­ni­fic­antly, and the res­ult­ant com­pos­ite sheet mater­i­al demon­strated excel­lent water-res­ist­ance and high strength in addi­tion to its high levels of bio­de­grad­ab­il­ity in sea­wa­ter. Asso­ci­ate Pro­fess­or Asoh says, ​“Since we were able to devel­op a mar­ine bio­de­grad­able plastic sheet by com­bin­ing famil­i­ar mater­i­als such as starch and cel­lu­lose, because these mater­i­als are cheap, and the man­u­fac­tur­ing pro­cess is simple, we can expect that the developed mater­i­al will be put to prac­tic­al use soon. We have great expect­a­tions that our mater­i­al will help solve the grow­ing glob­al prob­lem of mar­ine debris accu­mu­la­tion and have a major soci­et­al impact.” On the effects of their newly developed tech­nique, Pro­fess­or Uyama adds, ​“The effect­ive use of low-cost bio­mass, which is what is afforded by our tech­nique, will lead to a reduc­tion in green­house gas (e.g., CO₂) emis­sions, thereby pos­i­tion­ing this tech­no­logy among the key envir­on­ment­al tech­no­lo­gies emer­ging from Japan for the rat­i­fic­a­tion of the Par­is agree­ment.” This product is expec­ted to not only con­trib­ute sig­ni­fic­antly to a reduc­tion in the amount of new mar­ine debris depos­ited glob­ally, but also to a more effi­cient and sus­tain­able mater­i­al cyc­ling pro­cess and to the reduc­tion of green­house gases, giv­ing it the poten­tial to enable the real­iz­a­tion of the United Nation’s Sus­tain­able Devel­op­ment Goals, the COP25, and the policies of the Japan­ese gov­ern­ment-led Moon­shot Pro­gram (Tar­get 4, resource cir­cu­la­tion). Source: Osaka Uni­ver­sity, Research release, 03.05.2020