Advanced Powder Technol. , Vol. 15, No. 2, pp. 215– 225 (2004) Ó VSP and Society of Powder Technology, Japan 2004. Also available online - www.vsppub.com Original paper Mechanochemical dechlorination of polyvinyl chloride by co-grinding with various metal oxides TSUYOSHI INOUE 1;¤ , MIYUKI MIYAZAKI 1 , MASATAKA KAMITANI 1 , JUNYA KANO 2 and FUMIO SAITO 2 1 Sekisui Chemical Co. Ltd., 2-2 Kamichoshi-cho Kamitoba Minami-ku, Kyoto 601-8105, Japan 2 Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira Aoba-ku, Sendai 980-8577, Japan Received 6 December 2002; accepted 16 June 2003 Abstract —Polyvinyl chloride powder was ground with one of the oxide powders, i.e. CaO, Fe 2 O 3 , SiO 2 and Al 2 O 3 , in air by a planetary ball mill to investigate the mechanochemical dechlorination of PVC. Grinding causes the size reduction of the each component. The PVC powder sample is degraded by grinding with reduction of molecular weight, forming C C bonds in its structure. The dechlorination occurs in all the ground mixtures, but its phenomenon is classied into two types. One is the solid-phase reaction to form chlorides, CaOHCl and FeCl 2 2H 2 O, when CaO and Fe 2 O 3 powders are used. The other is the release of HCl gas by degradation when SiO 2 and Al 2 O 3 powders are used. All the same, the dechlorination yield increases not only with an increase in grinding time, but also with excess of oxide powder. Keywords: Grinding; polyvinyl chloride; oxide; dechlorination;degradation. 1. INTRODUCTION Polyvinyl chloride (PVC, [ (CH 2 CHCl) n ], n D polymerization degree) has a unique chemical property of high stability for heat and chemicals, and it has a potential to exhibit a wide variety of plastic-elastic properties from exible to rigid PVC products by mixing with plasticizers and additives. In addition, the PVC production industries plays a signicant role in consuming chlorine emitted from soda production industries. Also, PVC products exhibit high cost performance in comparison with other plastics, so a large amount of PVC raw material has been used for industrial, agricultural, medical goods, etc. However, after the usage of such PVC products, they would be wastes, which are disposed of mainly by reclamation and combustion. The former needs a huge land area, which is not ¤ To whom correspondence should be addressed. E-mail: t-inoue@jiwet.or.jp