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研究了热老化处理对丁苯胶乳体系机械稳定性的影响.发现丁苯胶乳在高温老化过程中,胶粒容易团聚并形成凝胶,老化处理温度越高,凝胶出现时间越短,但是它的机械稳定性却随着老化处理时间的延长和老化处理温度的升高反而不断提高.为了阐明这种异常现象,测试了不同老化处理温度下胶乳的粒子尺寸、剪切作用下的凝胶比率、丁苯分子的结构与分子量分布,以及胶粒的力学强度随老化时间的变化规律,分析了影响机械稳定性的可能因素.结果表明,胶乳体系中丁苯分子在高温老化过程中发生了轻度的交联反应,导致胶乳干膜的300%定伸模量提高.进一步研究还发现,这个定伸模量与胶乳的机械稳定性具有对应关系,胶乳干膜的定伸模量越大,胶乳的机械稳定性越高,因此造成机械稳定性大幅上升的主要原因很可能是热老化交联后刚性较大的胶粒在高速剪切碰撞时难以及时融合.
The effect of thermal aging treatment on the mechanical stability of SBR latex system was studied. It was found that SBR agglomerates easily and forms gel during the aging process of SBR. The higher the aging temperature, the shorter the gel appearance, But the mechanical stability with the aging treatment time and increasing the aging temperature but rising.In order to clarify this anomaly, the test under different aging temperature latex particle size, gel shear rate under the ratio , The structure and molecular weight distribution of SBR, and the change law of the mechanical strength of colloidal particles with the aging time, the possible factors affecting the mechanical stability were analyzed.The results showed that the SBR molecules in the latex system were light Degree of cross-linking reaction, resulting in 300% modulus of dry latex film increased modulus.Further study also found that the modulus of elasticity and the mechanical stability of the latex has a corresponding relationship, the greater modulus of dry latex film, The higher the mechanical stability of the latex, the main reason for the substantial increase in mechanical stability is likely due to the fact that the more rigid colloidal particles after heat aging crosslinked And integration time.