Novel decomposition of polycarbonate and effect for marine ecosystem

Abstract

Analysis of pollution of the ocean plastics is presently being extensively carried out but special attention should be direct to matters. It is widely believed that plastic dose not decompose in the ocean. Certain contaminants, bisphenol-A (BPA) that serves the material for polycarbonate (PC) and epoxy resin (EPX) both of which may possibly be elute or degrade from commercial products, have often been detected in rivers, lakes and oceans. To clarify in detail the extend of this impact of this situation, purified PC (BPA free) was decomposed at temperatures range 50-230 °C. PC was seen to start decomposing at 50 °C over a 3 day period to generated 11 μg kg^-1 BPA. Based on the rate constants of BPA, the activation energy was calculated 42.0 kJ mol^-1. Since this value is almost same as the EPX and polystyrene (PS) of each decomposition. Based on the PC decomposition rate and the actual BPA value in the deep sea, the 280 million metric tons (MT) BPA in the world ocean was estimated. Unlike plastics, BPA shows endocrine disrupting in fish. It should thus be considered that degraded PC and EPX pose a serious threat to the marine ecosystem, directly.

Fig. 1. Preparation for reaction material and commercial samples.

Fig. 2. GPC chromatogram of original, purified and decomposed PC (230 °C, 30 min).

Fig. 3. Effects of reaction temperature (time: 60 min).

Fig. 4. Vertical BPA and SO value in Northwest Pacific Ocean.