Glass-transition temperature of poly(vinylidene fluoride)-poly(methyl acrylate) blends: Influence of aging and chain structure

The glass-transition temperature (T-g) of the poly(vinylidene fluoride) (PV F2)-poly(methyl acrylate) (PMA) blends increase with aging time. The T-g ve rsus log(time) plots are straight lines whose slope values depend on the he ad to head (H-H) defect content of PVF2 samples and on the composition of t he blends. The values of polymer-polymer interaction parameters (chi) incre ase with an increase in the H-H defect of PVF2 for a fixed composition of t he blend. Consequently, the T-g of the blend decreases with an increase in the H-H defect of the PVF2 sample. However, after aging for longer times th is decrease of the T-g with H-H defects is lower than those of the unaged b lends. The possible reasons are discussed. (C) 2000 John Wiley & Sons, Inc.