Thermal degradation of blends of Poly (vinyl chloride) /Polyurethane (PVC/PU) was examined by thermogravimetry, differential thermal analyis, ultraviolet-visible spectroscopy, measurement of gel content and chemiluminescence analysis. The results obtained were as follows : Thermal degradation of the blends started at lower temperatures than that of each homopolymer. Polyene formation of PVC caused by HCI elimination reaction and successive gel formation by crosslinking reaction were accelerated by the blend of PU, and maximum effect was observed at 1 I blend ratio (wt) Relative amount of chemiluminescence of PU due to thermal oxidation was reduced remarkably by the blend of PVC. Thus, thermal degradation of the each component polymer in the blends was accelerated by the other component.

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Catalytic degradation of PE was carried out in the presence of zeolite catalyst for the utilization of waste PE. The sample PE (2g) and the zeolite (or silica-alumina) catalyst (0.5-2g) was placed on the bottom of the tube reactor and the reaction was conducted from 160 to 320°C. The number of molecules of starting PE was 1.51 × 10¹⁹/g and for the degraded polymer with the zeolite catalyst, 1.58-1.35 × 10¹⁹/g at 140-300°C. With the silica-alumina catalyst at 300°C for lh., the number of molecules remarkably increase to 8.60 × 10¹⁹/g. The molecular weight of the starting polymer (Mn =3.98 × 10⁴) slightly increased on treatment with the zeolite catalyst at 300°C, but sharply decreased to 0.9 × 10⁴ with the silica-alumina catalyst. The chain ends of degraded polymer by zeolite catalyst were saturated with methyl groups, chemically stable constituents. Degradation products recovered by radical chain reactions of polyolefin are giving constituents such as olefins in most cases. In contrast, the molecular weight of catalyically degraded PE, a chemically stable constituent can be controlled through selection of appropriate degradetion conditions.

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