白炭黑的功能化改性及其改性橡胶基复合材料的制备与表征

利用沉淀法白炭黑生产工艺,在相同的条件下,选用不同质量分数的羟基羧酸酯作为改性剂进行湿法改性,研究了白炭黑/天然橡胶(NR)复合橡胶的力学性能、动态性能以及动态生热性能。结果表明:制备的白炭黑均为非晶态白炭黑,采用质量分数为6%的羟基羧酸酯改性的白炭黑,其分散性好,颗粒分布均匀,呈近球状,经羟基羧酸酯改性后的白炭黑有效的去除了部分亲水基团,改善了其在NR中的分散性。随着白炭黑用量的增加,分散性变差,损耗因子和动态温升均有所提高,Payne效应增大。当白炭黑用量达到临界值(白炭黑与NR质量比为40∶100)时,白炭黑/NR复合材料表现出较好的性能,改性白炭黑/NR复合材料比未改性白炭黑/NR复合材料的硬度、拉伸强度、断裂伸长率有所提高,而磨耗体积和动态生热则有所下降。动态力学性能测试结果表明,改性白炭黑与天然橡胶的质量比为40∶100时,改性白炭黑/NR复合材料的60℃滚动阻力损耗因子由0.123降到0.104。SEM结果表明,改性白炭黑在橡胶基体中的分散性优于未改性白炭黑,与NR基体界面结合的更加紧密。

Preparation and characterization of functionalization of silica and its rubber matrix composites

Using the process technology of precipitated silica,under the same condition,different mass fractions of hydroxy carboxylic ester were added into precursors as modifier in order to wet modification,the mechanical proper-ties,dynamic properties and dynamic heat generation properties of silica/nature rubber (NR)composites were inves-tigated.The results show that the silica prepared is amorphous silica,the dispersion of silica modified by the mass fraction of 6% of hydroxy carboxylic ester is good,particles are distributed evenly,which shapes like a ball,and some hydrophilic groups of silica are eliminated effectively by using hydroxy carboxylic esters,therefore,the disper-sity of silica in NR is improved.When the amounts of silica increase,the mechanical property,loss factor and dy-namic heat generation of the composites are enhanced,meanwhile,the Payne effects are also increased.By the time the content of silica reaches its critical value (the mass ratio of silica to NR is 40∶100),the mechanical properties of silica/NR composites would have better performance,the properties of modified silica/NR composites is better than unmodified silica/NR composites,as results of the hardness and tensile strength and elongation at break are in-creased,the wear volume and dynamic heat generation are decreased.Dynamic mechanical performance test shows that when the mass ratio of modified silica to NR is 40∶100,the rolling resistance of modified silica/NR composites loss factor at 0 ℃ keep almost constant,but the skid resistance of composites loss factor at 60 ℃ drops from 0.123 to 0.104.The results of SEM prove that better dispersion and stronger interfacial interaction are achieved in NR matrix filled by modified silica than unmodified silica.