摘要 : Batch emulsion copolymerizations of butadiene, methyl methacrylate (MMA), methacrylic acid (MAA) and hydroxyethyl methacrylate were performed in RCle reactor, and the product vulcanized to form a film typical of those used for bar... 展开 Batch emulsion copolymerizations of butadiene, methyl methacrylate (MMA), methacrylic acid (MAA) and hydroxyethyl methacrylate were performed in RCle reactor, and the product vulcanized to form a film typical of those used for barrier products (gloves and condoms). The water vapour transmission (WVT) or breathability and physical properties (such as tensile strength and elongation at break) of the films were measured. Factorial design was used to vary the concentration of monomers in the copolymerizations. Methacrylic acid is a hydrophilic monomer and its distribution in or on the particles would be expected to affect WVT. Characterization by ultracentrifugation, nuclear magnetic resonance and infrared spectroscopy showed that most of the methacrylic acid units were buried inside the particles. This appears to be responsible for a relatively low WVT rate, probably due to the absence of hydrophilic (MAA-rich) domains inside the film. When centrifuged, the latex shows two particle-containing layers; characterization of the latex revealed the presence of MMA-rich domains in one layer, probably arising from secondary particle formation late in the polymerization. The butadiene-to-MMA ratio probably dominates tensile strength through vulcanization with sulfur. The elongation at break was independent of both the butadiene-to-MMA ratio and the MAA concentration over the range studied (ascribed to competing effects), but dependent upon the total crosslinker concentration. (c) 2007 Elsevier Ltd. All rights reserved. 收起