Development of polymers which are friendly to environment

The radiation processing of polymer materials has been utilized widely in the fields of making electric wire and cable coating heat resistant by cross linking, the production of foaming plastics and heat contraction tubes, the pretreatment of the rubber sheets for tires and so on. However, in the development of radiation processing, it is desirable to meet the social trend of regarding environment as important. The production of plastics in 1992 was 12.6 million t, and the amount of waste was 6.9 million t. Only 11% of the waste was reused as plastics, and 17% was used as the fuel for power generation. The rest 4.95 million t was used for land reclamation or incinerated. According to such background, the research and development of the polymer materials which do not contaminate environment at the time of their production and use, which are useful for cleaning environment, and which do not contaminate environment at the time of their abandonment, are desirable. The example of contaminating environment at the time of use is paint and ink. One of the countermeasures is radiation hardening. As the polymers which are useful for cleaning environment, there are gas-absorbing and heavy metal-collecting materials. As to the polymers which do not contaminate environment at the time of their abandonment, the reusability, easy natural decomposition and the materials that do not form and release harmful composition at the time of their abandonment are described. (K.I.)