Formation of linear polyenes in poly(vinyl alcohol) films catalyzed by phosphotungstic acid, aluminum chloride, and hydrochloric acid

摘要: Formation of linear polyenes–(CH=CH)n–via acid-catalyzed thermal dehydration polyvinyl alcohol in 9- to 40-µm-thick films this polymer containing hydrochloric acid, aluminum chloride, and phosphotungstic acid as catalysts was studied by electronic absorption spectroscopy. The concentration long-chain (n ≥ 8) polyenes is found monotonically increase with the duration treatment films, although kinetics process independent film thickness. In formation rate n 8 rapidly drops thickness decreases annealing time increases. As a result, at less than 10–12 µm, are not formed all these no matter how long is. reason for behavior that catalyzing evaporates from during treatment, evaporation inversely depending on