本研究以偏光顯微鏡在全偏光模式下觀察聚丙烯 (iPP)在電紡纖維表面穿晶形成過程，並分析其穿透光強度變化，藉由穿透光強度會隨晶核增加而上升的關係，可得晶核在纖維表面出現的初始溫度 (Ti)，此溫度之高低可判斷何種纖維誘導iPP穿晶的能力較佳。利用此方法可彌補當電紡纖維太細時無法細數核子的缺點。

首先探討纖維擺放方式、樣品厚度及降溫速率對穿透光強度分析造成的影響。後固定以4 oC/min降溫觀察不同纖維誘導iPP產生穿晶的過程，並以分析所得Ti比較纖維成核能力依序為：PBT ＞ PTFE ＞ PVA ＞ iPS ＞ PBO ＞ PET ＞ Nylon ＞ sPS。改變不同降溫速率時，iPP在纖維上的成核行為也不同，降溫速率愈快，Ti愈低。利用不同降溫速率所得Ti外插至速率為零時的值估算此纖維可形成穿晶的最高溫度。

實驗發現iPS纖維能誘導iPP產生beta晶體，降溫速率愈快，beta晶體數量愈多。iPP纖維在外觀熔化後仍具有優先成核的能力，顯示分子鏈順向度還存在；且隨著升溫次數愈多，成核位置會愈遠離纖維，顯示分子鏈有往外擴散的情況。由原子力顯微鏡可得纖維表面粗糙度依序為：PBO＞PBT＞iPS＞PET＞Nylon＞PVA＞sPS，在此發現纖維的Ti與粗糙度無太大關聯，而與纖維本質較相關。

Transcrystallization of polypropylene (iPP) on various as-spun fibers is investigated using a polarized optical microscope. By measuring the transmitted light intensity under cross-polarized microscopy, the initiation temperature (Ti) for transcrystallization was determined to represent the nucleating ability of fibers.

First, we studied on the effects of fiber direction, sample thickness, and cooling rates on the transmitted light intensity. Then we compared the Ti of various fibers by fixing the cooling rate of 4 oC/min. The nucleating ability of fibers can be ranked as follows： PBT ＞ PTFE ＞ PVA ＞ iPS ＞ PBO ＞ PET ＞ Nylon ＞ sPS. Ti significantly depends on the cooling rate; the higher the cooling rate is, the lower the Ti obtained. We can estimate the maximum temperature for transcrystalline layer to develop by extrapolation of Ti at cooling rate zero.

iPS fibers can induce the beta-crystal form of iPP during cooling. The content of beta-crystal form increases with increasing cooling rate. iPP fibers can induce nucleus earlier than the bulk, revealing that the chain orientation of fiber is preserved. The nucleated site is gradually far away from the fiber after repeatedly heating cycles. It indicates that the oriented polymer chains diffuse to the bulk. Surface morphology is revealed by atomic force microscope (AFM). The order of fiber surface roughness is : PBO＞PBT＞iPS＞PET＞Nylon＞PVA＞sPS. Our results showed that Ti has no significant relationship with surface roughness but depends on the intrinsic property of fibers.

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