丙烯酸酯改性PVAc乳液胶粘剂及其热性能研究

以丙烯酸丁酯(BA)和丙烯酸(AA)作为醋酸乙烯酯(VAc)的改性共聚单体,采用半连续种子乳液聚合法制备改性聚醋酸乙烯酯(PVAc)乳液,并以此作为木材胶粘剂。研究结果表明:以粘接强度、吸水率和黏度为考核指标,采用单因素试验法优选出改性乳液的最佳单体配比为w(BA)=15%、w(AA)=3%(均相对于VAc质量而言);改性乳液的平均粒径为200⁴00 nm,粒径分布较均一;引入BA和AA后,改性乳液的Tg(玻璃化转变温度)变化较明显,改性胶膜的热稳定性随改性单体含量增加而略有增大,当w(BA)≥5%、w(AA)≥1%时,改性胶膜的起始热分解温度比VAc均聚物提高了60℃左右。

Study on PVAc emulsion adhesive modified by acrylate and its thermal property

With butyl acrylate(BA) and acrylic acid(AA) as modified comonomers of vinyl acetate(VAc),a modified polyvinyl acetate(PVAc) emulsion,which could be used as wood adhesive,was prepared by semicontinuous seed-emulsion polymerization method.The research results showed that with bonding strength,water absorption and viscosity as evaluation indexes,the optimal monomer ratios of modified emulsion,which mass fractions of BA and AA were 15% and 3% respectively in VAc,were preferred by single-factor experiment method.The average particle size of modified emulsion with uniform distribution was 200-400 nm.After the BA and AA were introduced into system,the Tg(glass transition temperature) of modified emulsion had obvious change.The thermal stability of modified adhesive film was increased slightly with increasing modified monomer contents,and the initial thermal decomposition temperature of modified adhesive film was about 60 ℃ more than that of VAc homopolymer when mass fractions of BA and AA were not less than 5% and 1% respectively.