Polyacetals and poly

Gaseous monomers may also be trapped within the processing equipment and accidents have occurred as a consequence of the resulting pressure buildup. In the case of the polyacetals and poly(vinyl chloride) it is reported that at elevated temperatures these materials form a more or less explosive combination so that it is important to separate these materials rigorously at the processing stage. 

E. Schacht, V. Toncheva, K. Vandertaelen, J. Heller, Polyacetal and poly(ortho ester)-poly(ethylene glycol) graft copolymer thermogels preparation, hydrolysis and FITC-BSA release studies, J. Control. Release 116 (2006) 219-225. 

J. Heller, D.W.H. Penhale, R. F. Helwing, B. K. Fritzinger, and R. W. Baker, Release of Norethindrone from Polyacetals and Poly(Ortho Esters), AIChE Sympositmi Series No. 206,... 

According to the authors, the cationic species present in the polymerization mixture participate in not only transacetaliza-tion but also transetherification reactions, yielding copolymers with the polyacetal and poly(ethylene oxide) blocks (see Scheme 1). These copolymers can function as the in sitM-formed suspension stabilizers adsorbed onto the surface of polyacetal particles via the polyacetal blocks and with the poly( ethylene oxide) segments providing steric stabilization. 

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