Experimental Course Design for Observing Different Crystallization Forms of Polypropylene Caused by Glass Fiber Extraction Using Microscopy with Hot Stage

The phenomenon of polypropylene isothermal crystallization with transcrystallinity structure induced by pre-embedded glass fiber is observed by controlling the temperature on a hot stage. After that, the pre-embedded glass fiber is extracted from the polypropylene melt, and the transcrystallinity induced by shearing and its growth process is observed. Finally, the relaxation characteristics of molecular chain during crystallization process are verified by the design of annealing experiment after fiber extraction. This experiment has a brand-new design for the high polymer physics experiment of observing the morphology of polypropylene spherulites with the traditional micropolariscope, which deepens the students’ understanding of spherulite and transcrystallinity structures under heterogeneous nucleation and shearing-induced crystallization. The innovative and reasonable experiment is easy to operate and has remarkable teaching effect.