白炭黑用量对光交联丁腈橡胶/白炭黑共混体系及其性能影响

Effects of Silica Amounts on Properties of Photocrosslinked NBR / Silica Composites

采用紫外光对丁腈橡胶/白炭黑(NBR/silica)共混体系进行光交联改性,并通过凝胶含量测试、力学性能测试、热延伸测试、热重分析和动态热机械分析,探究丁腈橡胶/白炭黑光交联特性及白炭黑用量对共混体系相关性能的影响。凝胶含量实验表明,随着白炭黑用量的增加,凝胶含量先上升后下降,在50 phr时出现最大值,拉伸强度显著上升,断裂伸长率下降。热延伸和热重分析表明材料热稳定性提升。动态热机械分析反映了材料刚性的增加抑制了分子链的运动,从而导致储存模量和玻璃转化温度上升。

The photo( UV)-initiated crosslinking behavior of nitrile rubber / silica and its related properties were investigated through determination of the gel content,mechanical measurements,heat extension,thermo gravimetric analysis( TGA) and dynamic mechanical thermal analysis( DMTA). The results show that the gel content increases with increasing amounts of silica up to 50 phr,whereas decreases with further increasing the amounts of silica. The mechanical measurements show a remarkable increase in tensile strength,while the corresponding values of elongation at break decrease. The results of heat extension test and TGA illustrate that the thermal stability of NBR / silica is enhanced evidently along with increasing amounts of silica. The data of DMTA indicates that increasing the amounts of silica restricts mobility of the macromolecular chains,which leads to increase in storage modulus( E') and glass transaction temperature( Tg).