影响废旧轮胎胶粉热-机械剪切脱硫再生效果的因素

Influence factors of thermal-mechanical shearing devulcanization for waste tire rubber powder

利用自行研制的长径比为60/1的强剪切型双螺杆挤出机对废旧轮胎胶粉进行热-机械剪切脱硫,用傅里叶变换红外光谱对脱硫胶粉进行了表征,考察了胶粉粒径和喂料螺杆转速与主机转速之比对脱硫胶粉凝胶含量、交联密度及再生胶力学性能的影响,以及脱硫过程中胶粉相对分子质量及其分布的变化。结果表明,随着胶粉粒径的增大,胶粉所受到的剪切力增强,脱硫效果也越好。随着转速比的增加,胶粉的脱硫程度提高;脱硫过程的第1个阶段是交联网络的破坏,第2个阶段除交联网络的破坏外分子主链也发生降解,再生胶的力学性能先增大后减小;当转速比为1.4时再生胶的扯断伸长率和弹性最好,拉伸强度也相对较高。

The thermal-mechanical shearing devulcaniza- tion of waste tire rubber powder was conducted in a strong shearing twin screw extruder with the length-diameter ratio of 60/1 in screw developed by Changzhou University, the devul- canized rubber powder was characterized by Fourier trans- form-infrared spectroscopy, and the effects of the particle size of waste tire rubber powder and the rotation speed ratio of feeding screw to main screw on the crosslinking density and gel content as well as the changes of the relative molecular mass and its distribution of the devulcanized rubber powder were investigated. The results showed that the shear force ex- erted on the rubber powder increased with increasing particle size of the rubber powder, and the larger the particle size,the better the devulcanization effect. The devulcanization ex- tent of the rubber powder improved with the increase of rota- tion speed ratio. In the first devulcanization stage, the crosshnking networks were disrupted, and in the second stage, the molecular backbones were decomposed besides the disrupture of crosslinking networks, so that the mechanical properties increased first and then decreased. When the rota- tion speed ratio was 1.4, the elongation at break and the elasticity of the reclaimed rubber were the best, and the ten- sile strength was also relative good.