BATCH AND SEMICONTINUOUS EMULSION CO-POLYMERIZATION OF VINYL-ACETATE BUTYL ACRYLATE .2. MORPHOLOGICAL AND MECHANICAL-PROPERTIES OF CO-POLYMER LATEX FILMS

In the reported experiments, vinyl acetate/(VAc)-butyl acrylate/(BuA) copolymer latex films of various copolymer compositions were investigated for their morphological properties by electron microscopy techniques, and for their mechanical properties by dynamic mechanical spectroscopy (DMS), differential scanning calorimetry (DSC), and tensile strength measurements. Batch copolymer latex films showed domains of PBuA dispersed in PVAc matrix; the domain sizes were increased with increased BuA content. Glass transition temperatures T//g determined from DMS and DSC indicated the presence of two, low and high, transition temperatures for batch latex films. The two temperatures approached the individual homopolymers, with increased PBuA content up to 51 mol%. Semicontinuous latex films showed only one single T//g. Tensile properties of the batch copolymer films showed a higher ultimate tensile strength, higher Young's modulus, and lower percent elongation to break compared to semicontinuous latex films.