Abstract In this study, the effects of different zeolite based catalysts, initial crosslinking, temperature and heating rate as key process and structural parameters on the thermal degradation of natural rubber (NR) were investigated. The product composition containing liquid, gas and coke yield as well as the varied components of liquid product as a function of the studied parameters in the stirred reactor were compared. The degradation temperature, heating rate, initial crosslinking and catalyst type affected on the formation of aromatic and aliphatic products appreciably. The results showed that the thermal pyrolysis of natural rubber tended to follow the un-zipping and Diels-Alder mechanisms significantly though the catalytic pyrolysis reduced the unzipping share and enhanced the Diels-Alder reactions. Meanwhile, the results showed that the non-vulcanized sample produced the maximum condensed hydrocarbons at 450 °C and the medium heating rate in the studied range. The studied degradation mechanism using TGA instrument indicated that the ratio of crosslinking over chain scission and unzipping decreased with increase in temperature and heating rate. Generally, it showed that the double bond in the polymer structure beside the heating rate could played an important role in the degradation mechanism and the products. The results indicated that activation energy decreased with increasing the heating rate (171.06–136.51 kJ mol−1).

中文翻译：

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温度、加热速率、初始交联和沸石催化剂作为关键工艺和结构参数对天然橡胶 (NR) 降解生产有价值烃的影响

摘要 在本研究中，研究了不同沸石基催化剂、初始交联、温度和加热速率作为关键工艺和结构参数对天然橡胶（NR）热降解的影响。比较了包含液体、气体和焦炭的产物组成以及作为搅拌反应器中研究参数的函数的液体产物的不同组分。降解温度、加热速率、初始交联和催化剂类型对芳香族和脂肪族产物的形成有显着影响。结果表明，虽然催化热解降低了解链份额并增强了Diels-Alder反应，但天然橡胶的热解倾向于显着遵循解链和Diels-Alder机制。同时，结果表明，未硫化样品在 450 °C 和研究范围内的中等加热速率下产生最大的冷凝烃。使用TGA仪器研究的降解机理表明，随着温度和加热速率的增加，交联与断链和解链的比率降低。总体上表明，除加热速率外，聚合物结构中的双键对降解机理和产物也起着重要作用。结果表明，活化能随着加热速率（171.06-136.51 kJ mol-1）的增加而降低。使用TGA仪器研究的降解机理表明，随着温度和加热速率的增加，交联与断链和解链的比率降低。总体上表明，除加热速率外，聚合物结构中的双键对降解机理和产物也起着重要作用。结果表明，活化能随着加热速率（171.06-136.51 kJ mol-1）的增加而降低。使用TGA仪器研究的降解机理表明，随着温度和加热速率的增加，交联与断链和解链的比率降低。总体上表明，除加热速率外，聚合物结构中的双键对降解机理和产物也起着重要作用。结果表明，活化能随着加热速率（171.06-136.51 kJ mol-1）的增加而降低。