Deterioration of novel polyesterurethane elastomers in outdoor exposure

摘要

Poly(esterurethane)-elastomers based on novel polyester glycols with methyl side groups were exposed outdoors for 2 years. The polyester glycols used are poly(β-methyl-δ-valerolactone)glycol (PMVL), poly(3-methyl pentamethylene adipate) glycol (PMPA), poly(nonamethylene-co-2-methyl octamethylene carbonate) glycol (PNOC). A mixture of PNOC and poly(dimethyl siloxane)glycol (PNOC/PDMS) was also used. Polyurethane network elastomers, were prepared from these polymer glycols, 4,4'-diphenylmethane diisocyanate, and a mixture of 1,4-butanediol with trimethylol propane by a prepolymer method. The deterioration behavior of the PUEs was measured by means of polarizing microscopy, DSC, tensile testing, dynamic viscometry, and ESR. The novel polyester- based PUEs have better weatherability than poly(oxytetramethylene) glycol (PTMG)-based PUE. The mechanisms of deterioration are discussed.