Supercritical Chemical Recycling of plastics with Continuous Mixture Kinetics

利用连续混合动力学的理论发展和计算机软件的理论计算，对聚酯、尼龙等聚合物在超临界流体中的分解进行了实验和数据分析。作为理论研究，分子量分布用连续分布函数表示。用连续动力学理论分析了其分解行为。该理论包括聚合物的分子量分布(MWD)随机性和专一性的变化以及单体组分的二次反应。为开发塑料化学回收技术，研究了塑料在超临界水或甲醇中的降解过程。采用高压间歇反应器或连续流反应器。作为塑料样品，采用了回收最多的缩聚塑料PET。研究了PET在超临界甲醇和超临界水中的降解，以开发一种废塑料的化学回收工艺。对实验数据进行了连续动力学分析。得到了产物的相对分子质量随反应时间的变化关系。测定了包括副产物在内的分解产物中单体组分的产率，以阐明反应机理。还研究了尼龙6在超临界水中的降解。在超临界水中对加成聚合塑料和缩聚塑料进行了分解。将连续混合动力学成功地应用于塑料在超临界流体中降解的分析和模拟。

Experiments and the data analysis for decomposition of polymers such as PET and Nylon were carried out in supercritical fluid by using theoretical development of continuous mixture kinetics and theoretical calculation with computer software. As a theoretical study, molecular weight distribution was expressed by continuous distribution function. Continuous kinetics theory was developed to analyze the decomposition behavior. The theory includes molecular weight distribution (MWD) change of polymer by random and specific scissions and secondary reactions for monomer components. Change of MWD and monomers as a function of time was simulated by the continuous kinetics with Gamma distribution for MWD.To develop chemical recycling technology of plastics, degradation of plastics in supercritical water or methanol was studied. High pressure batch reactor or continuous flow reactor were used. As a sample of plastics, PET was adopted which is most recycled condensation polymerization plastics. Degradation of PET in supercritical methanol and supercritical water was investigated, to develop a chemical recycling process of waste plastics. Continuous kinetics analysis was applied to the experimental data. The MWD of the products was obtained as a function of reaction time. The yields of monomer components of the decomposition products including by-products were measured to clarify the reaction mechanism. Degradation of nylon 6 in supercritical water was also studied. Addition polymerization plastics as well as condensation polymerization plastics were decomposed in supercritical water. Continuous mixture kinetics were successfully applied to the analysis and simulation for plastics degradation in supercritical fluids.