通过自主研发的组装式叶片挤出机，采用动态可视化技术在线观察不同尺寸的结晶型聚丙烯的熔融过程，分析结晶型聚合物在叶片挤出机中的熔融规律和机理．研究表明:聚丙烯在叶片挤出机中的熔融过程分为全固体、富固体和富熔体 3 个阶段;在全固体和富固体熔融阶段，固体颗粒产生很大的塑性变形，固体颗粒在热传导和塑性耗散热的共同作用下熔融;而在富熔体熔融阶段，可以明显观察到固体颗粒的熔融，熔融过程主要受熔体黏性耗散热的影响;熔融所需 VPCU 组数受最难融固体颗粒(最大固体颗粒)控制，小颗粒物料比大颗粒物所需 VPCU 组数少．

The melting process of crystalline polypropylene with different sizes was observed on line by means ofdynamic visualization technique through a self- developed assembled vane extruder,and the melting law and mecha-nism of the polymer were also analyzed.The results show that (1) the melting process in the vane extruder includesthree stages,namely the full- solid melting stage,the solid- rich melting stage and the melt- rich meting stage;(2) in the full- solid and the solid- rich melting stages,solid pellets may generate large plastic deformation,and themelting process is dominated by heat conduction and plastic dissipation heat,while in the melt- rich meting stage,themelting process of solid pellets can be obviously observed,and the melting process is dominated by viscous dissipationheat of the melt; and (3) the number of VPCU groups in the melt- rich meting stage is controlled by the hardest melt-ing pellets (namely the largest pellets),and more VPCU groups are required for the melting of small pellets.