Dechlorination of PVC by a Mechanochemical Treatment under Atmospheric Condition.

Room-temperature dechlorination process for polyvinyl chloride (PVC) has been developed. The process employs a mechanochemical (MC) treatment of PVC and CaO mixture followed by washing of mixture with water. MC reaction between PVC and CaO was induced by the treatments with a planetary mill and a new type of mill named TS-type MC reactor, which converted PVC into polyethylene and CaOHCl. The former product essentially remains undissolved in water while the latter dissolves. Addition of excess CaO to PVC accelerates the reaction and enhances the yield of dechlorination to over 95% within 120 minutes for the MC treatment with planetary mill. A scale-up test with a TS-type MC reactor also gave promising results of dechlorination yield over 90% for 10 hours. Therefore the MC treatment of PVC with CaO under atmospheric condition would be promising in the practical application of dechlorination process.