Study Of Structure And Properties Of PEN Fibers Prepared By Different Methods And Short PEN Fiber Reinforcing PET

Poly(ethylene-2,6-naphthalate)(PEN) fibers have been prepared by twodifferent methods--conventional high-speed melt spinning and spin-drawprocess. A comparison of the structure and properties of various PEN fiberswas conducted using WAXD, DSC, sonic velocity and tensile measurements.The results show that the fiber samples produced by high-speed spinning andspin-draw process possess a different crystalline form and crystalline sizes.The structure and physical properties of PEN fibers spun at speeds varyingfrom 6 to 8 km/min are similar. In contrast, a significant different of Young'smodulus, breaking tenacity and elongation at break was observed forspin-drawn fibers. This may be attributed to the different draw ratio adoptedin preparing various samples. Fiber reinforced composites were prepared with short PEN fiberand PET resin. Structure and property of various composites were -iii-北 京 化 工 大 学 硕 士 学 位 论 文studied using WAXD, DSC , SEM and tensile measurements. The resultsshow that the PET resin is amorphous in the composites and the coldcrystallization temperature of PET is heightened with increasing PENcontent. The Young's modulus and breaking tenacity of composites areimproved somewhat by adding short PEN fibers. Such improvement,however, is not stable, because the linkage between PEN fiber and PETresin is not so sticky.