尿素改性聚醋酸乙烯酯乳液的合成

Polyvinyl Acetate Emulsion Modified by Urea

采用半连续种子乳液聚合方法合成了低固含量的聚醋酸乙烯酯乳液,并向乳液中添加尿素对其进行改性,研究了尿素添加量对乳液性能的影响,并采用傅里叶红外光谱(FTIR)、动态力学分析仪(DMA)、热重分析仪(TGA)、激光粒度仪等现代分析手段对乳液性能进行了表征。研究表明,尿素的添加使得乳液黏度降低,且黏度随剪切作用的变化速率变小,剪切应力减小,乳液胶接强度先升高后降低,在尿素添加量为60%时达到最大值,膜的储存模量、耐热性、耐水性及稳定性提高;尿素的添加增大了乳液粒径,而粒径分布变化不大。

An experiment was conducted to synthesize Polyvinyl acetate（PVAc） emulsion with the solid content of about 20% by the method of semi-continuous seeded emulsion polymerization.Urea was added into the emulsion to modify PVAc,and the effects of the amount of urea on the properties of the emulsion were studied by utilizing Fourier transform infrared spectroscopy（FTIR）,dynamic mechanical analysis（DMA）,thermogravimetric analysis（TGA） and laser granularity instrument.Results indicated that the viscosity of the emulsion decreased with the increase of addition amount of urea,and the changing rate and the shear stress also decreased with the change of shear rate.The bonding strength of PVAc increased firstly and then decreased,and the maximum value was achieved when the addition amount of urea was 60%.After the addition of urea,the storage modulus,heat resistance,water resistance and the stability of the coating of PVAc were improved,and the particle size of the emulsion increased,but the particle size distribution changed little.