生物可分解高分子正溫度係數效應之研究

The Study of Positive Temperature Coefficient Effect of Biodegradable Polymer

陳俊勳(Jun-Xun Chen)

指導教授 ： 芮祥鵬

國立臺北科技大學/工程學院/有機高分子研究所/碩士(2006年)

摘要

本篇研究是以生物可分解高分子PLA(聚乳酸)為基質，碳黑為填充導體，用塑譜儀均勻混煉，使高分子具有導電功能，形成導電高分子。利用其PTC效應，電阻能隨溫度急劇上升，亦即是當導電複合材料之溫度上升至一關鍵溫度時，其電阻會明顯地大幅上升，達到暫時絕緣或短路的效果。預計可應用於過熱保護裝置，並成為丟棄後可自然分解之保險絲。
本研究探討碳黑含量、碳黑種類、聚乳酸種類、量測系統及冷卻處理對正溫度係數（Positive Temperature Coefficient，PTC）效應的影響。藉由高阻計、微分熱掃瞄卡計（DSC）、廣角X光繞射（WXRD）、小角度X光繞射（SAXS）、雙平板流變儀 (SR5)等來分析生物可分解導電高分子之物性。從研究中發現，碳黑粒徑越小，導電度越高。摻入3％碳黑（CB）的PDLLA具有最佳的臨界濃度及PTC強度。除此之外，結晶度較低、結晶層厚度較大、平衡熔點較高以及網狀結構的產生具有較佳的PTC強度。透過冷卻處理，發現到冷卻速率越快其PTC強度越高，與自然降溫相比較，多了五個數量級。

關鍵字

聚乳酸 ； 混煉 ； 正溫度係數 ； 碳黑

並列摘要

This research use the biodegradable polymer Polylactide acid (PLA) as a host material with carbon black as the pack conductor and blend the compound by brabender in order to become the conducting polymer. Utilizing the positive temperature coefficient (PTC) effect, the resistance of polymer will rise as temperature increasing sharply. In other word, when the temperature of conducting polymer rise to a key point, its resistance will rise by a widely range that will exhibit the function of the temporarily insulating result or shorting out.
This research explores the affection of Positive Temperature Coefficient (PTC) that relate to contents, sorts of carbon black, kinds of lactic acid, measurement system and cooling treatment. To analyze the properties of biodegradable conductive polymers by environment megohmmeter、Differential Scanning Calorimeter (DSC)、Wide-angle X-ray Diffraction (WXRD)、Small-angle X-ray Scattering (SAXS)、SR-5. It can be discovered that conductivity of carbon black will increase while particles are getting smaller. Poly (D,L-lactic acid) (PDLLA) has the best critical concentration and Positive Temperature Coefficient (PTC) that blends with 3％ carbon black. Moreover, the lower crystallinity will increase the thickness of crystal layers and melting point of balance. The formation of network configuration has better Positive Temperature Coefficient (PTC). Through cooling treatment it shows Positive Temperature Coefficient (PTC) is higher with faster cooling rate and has five more quantitative points that compare with natural cooling phase.

並列關鍵字

Polylactide acid ； blend ； Positive Temperature Coefficient ； carbon black

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