Supercritical Chemical Recycling of plastics with Continuous Mixture Kinetics

利用连续混合动力学理论的发展和计算机软件的理论计算，对PET、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，用连续分布函数表示分子量分布。发展了连续动力学理论来分析分解行为。该理论包括聚合物的分子量分布（MWD）的无规和特定的分裂和单体组分的二次反应的变化。采用γ分布的连续动力学模型模拟了聚合物分子量分布和单体随时间的变化。为了开发塑料的化学回收技术，研究了塑料在超临界水和甲醇中的降解。使用高压间歇式反应器或连续流动反应器。以回收利用率最高的缩聚塑料PET为研究对象。研究了PET在超临界甲醇和超临界水中的降解，以开发废旧塑料的化学回收工艺。对实验数据进行了连续动力学分析。获得产物的MWD作为反应时间的函数。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。研究了尼龙6在超临界水中的降解情况。在超临界水中对加聚塑料和缩聚塑料进行了分解。连续混合动力学已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.