废轮胎和天然橡胶在超临界甲苯中的解聚研究

Depolymerization of scrap tire or nature rubber in supercritical toluene

在300℃～360℃、3.7MPa～7.0MPa、反应20min～90min、投料比(甲苯与废轮胎或天然橡胶的质量比)5.0～10.0下,分别研究了废轮胎和天然橡胶在超临界甲苯中的解聚,着重考察了解聚率与反应条件的关系、以及解聚产物分布。在临界点附近,解聚率随温度、压力升高而增加;高于临界压力后,压力对解聚率的影响减弱。解聚产物主要为液相物和固相物,液相产物用色质联谱(GC/MS)分析表明,以芳香烃和烯烃类为主,且分子量大多小于300;固相产物经分析以碳黑为主。废轮胎和天然橡胶的解聚产物大部分是相似的,天然橡胶可以完全解聚,在同样条件下废轮胎解聚率低于天然橡胶。超临界甲苯在反应中对实验样品不仅起到溶胀和溶解作用,同时也参与了解聚反应。研究结果为选择解聚介质和操作参数提供了依据。

The depolymerization of scrap tire or nature rubber in supercritical toluene was studied. Experiments were carried out under the conditions of 300°C-360°C, 3.7 MPa-7.0 MPa, 20 min-90 min, toluene/sample weight ratio 5.0-10.0, respectively. The study was focused on the relationship between depolymerization and the reaction conditions and the depolymerization products distribution. Liquid products were analyzed by a gas chromatography coupled with a mass spectrometer. The results show that most of liquid products are similar in different experiment samples containing alkyl aromatic species and alkene. Their molecular weights are below 300. Supercritical toluene plays an important role, which is not only to swell and dissolve experiment samples, but also to participate in the depolymerization. The results obtained may enforce the basic knowledge on selecting depolymerization fluids and operating parameters correctly.