Key Laboratory of New Technology for Construction of Cities in Mountain Area (Chongqing University), Ministry of Education, Chongqing 400045, China; School of Civil Engineering, Chongqing University, Chongqing 400045, China.
School of Civil Engineering, Chongqing University, Chongqing 400045, China.
Waste Manag. 2018 Sep;79:516-525. doi: 10.1016/j.wasman.2018.08.024. Epub 2018 Aug 15.
Approximate rubber/bitumen homogeneous system formed by desulfurization and degradation of crumb tire rubber in bitumen under high temperature is beneficial to enhance the storage stability of rubberized bitumen. However, the main problems during the processing of desulfurized and degraded rubberized bitumen are aging caused by volatilization of light components, and burning or explosion due to the direct utilization of low flash point bitumen. Therefore, waste cooking oil was proposed as a safer medium to desulfurize and degrade crumb rubber prior to production of rubberized bitumen. This study focused on the feasibility and effectiveness of the application of waste cooking oil in desulfurizing and degrading rubber particles through co-pyrolysis of them at mild temperature (240-280 °C). Chemical and microscopic analyses were performed to investigate the structural changes of vulcanized rubber. Results showed that solubility of rubber powder reached above 60 wt% after pyrolysis in waste cooking oil, which increased with higher temperatures and more of oil, while increased to a maximum at 2 h and then decreased with the extension of time. The rubber hydrocarbon content decreased greatly, and dramatic reduction of carbon, hydrogen and sulfur elements happened according to component and elemental analyses. The surface of pyrolysis product was even and smooth without obvious rubber particles. The grooves and cavities of rubber residues in scanning electron microscopy micrographs proved that shedding of degraded polymer molecules occurred. Fourier transform infrared spectra revealed that breakage of carbon-sulfur, carbon=carbon and sulfur=oxygen bonds took place during pyrolysis, with appearance of natural rubber characteristic peak.
废旧轮胎胶粉在沥青中经脱硫降解形成的近似橡胶/沥青均相体系有利于提高橡胶沥青的储存稳定性。然而，脱硫降解橡胶沥青加工过程中的主要问题是轻组分挥发引起的老化，以及由于低闪点沥青的直接利用而导致的燃烧或爆炸。因此，废食用油被提议作为一种更安全的介质，在生产橡胶沥青之前对胶粉进行脱硫降解。本研究主要关注废食用油在温和温度（240-280°C）下共热解废橡胶颗粒脱硫降解中的可行性和有效性。通过化学和微观分析研究了硫化橡胶的结构变化。结果表明，废食用油中热解后橡胶粉的溶解度达到 60wt%以上，随着温度的升高和废食用油用量的增加而增加，在 2h 时达到最大值，然后随着时间的延长而降低。橡胶烃含量大大降低，根据元素分析，碳、氢和硫元素的含量也急剧减少。热解产物的表面均匀光滑，没有明显的橡胶颗粒。扫描电子显微镜照片中橡胶残留物的凹槽和空腔证明了降解聚合物分子的脱落。傅里叶变换红外光谱表明，热解过程中发生了碳-硫、碳-碳和硫-氧键的断裂，并出现了天然橡胶的特征峰。
