Transcrystallization in fiber-reinforced polypropylene composites

• Main Authors: Liu, Chih-Ren, 劉志仁
• Other Authors: Chi Wang
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/71397386275393309832

碩士 === 元智工學院 === 化學工程學系 === 85 === Measurements have been made using a polarized optical microsope equipped with hot stage to investigate the transcrystallization of PP on different fiber, namely Kevlar, carbon and PET fibers. Both the nucleationrate and induction time at various crystallizationtemperatures were determined.Based on the theory of heterogeneous nucleation, the interfacial free energy difference function of PP on different fibers were determinted and compared tothat in the bulk matrix. The morphology of various fibers surfac is observed using AFM and SEM. The relationon between surface morphology and nucleation ability of fiber was discussed in details. Effect of stress on the inductiontime, nucleation rate and linear crystal growth rate arestudied by pulling single fiber embedded in the PP melt with a smalltensile testing machine. Experimental results shows that the nucleation rate increases with increasingpulling rate. The effect of fiber-pullingon the crystal growth rate isnegligible at high crystallization temperatures However, a pronounced increacein growth rate was found at low crystallization tempeeratures. The regime transition, based on Hoffman's theory was applied and discussed here.