Unsaturated modified poly(vinyl alcohol). Crosslinking through double bonds

Poly(vinyl alcohol) (PVA) was esterified with 10-undecenoyl chloride to giv e polymers with different degrees of modification which were studied in ord er to find how the concentration of reactive sites can influence the crossl inking process. The polymers obtained were characterized by spectroscopic t echniques, elemental analysis and thermal methods. Weight average molecular weights and viscosities were determined. Thermal crosslinking of the doubl e bonds on the side chain took place in all cases, but was overlapped by th e degradation process. Thus, dicumyl peroxide had to be used to obtain the cured material and avoid degradation. Activation energies for radical initi ated crosslinking were determined by means of dynamic DSC studies. Isoconve rsional kinetic analysis was applied to DSC data and the dependences of act ivation energies on conversion degrees were obtained and compared with thos e obtained from polymers with the same pendant chain but a more flexible po lyether main chain. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.