A poly(vinylidene chloride)-based polymer is a good material for food packaging as a barrier for oxygen and steam; however, there are problems related to chemical recycling due to low temperature degradation. To aid in developing a chemical recycling method without the evolution of harmful hydrochloric acid (HCl) and organochlorines, we have proposed a dehydrochlorination process at a low temperature (around 423?K) using zinc(II) oxide (ZnO). ZnO particles dispersed into the polymer matrix were found to be effective for thorough dehydrochlorination because the reaction promoters (zinc chloride [ZnCl2] and water) spontaneously penetrated the polymer via exothermic reactions. As a result, only a small percentage of chlorine atoms remained with a low amount of HCl. The efficiency of dehydrochlorination was a result of increasing the contact area with ZnO particles using a heat-kneading apparatus. The catalyst ZnCl2 was involved in the cross-linking reaction to form C?C single bond. Due to exothermic reaction, the scission or isomerization to polyene and aromatics also proceeded over a short period, leading to a microporous carbonaceous solid with a surface area of 5??102?m2/g.

» Author: Tomohiko Okada, Satoru Sutoh, Kohtaro Sejima, Hiroki Tomohara, Shozi Mishima

» Publication Date: 01/01/2020

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