本實驗利用有機環保高分子-左旋聚乳酸(PLLA)以及新型紡織高分子材料-聚對苯二甲酸丙二酯(PTT),以PLLA為連續相,PTT為分散相,將PTT10~50%添加至PLA中,以溶液混煉的方式混成含有不同比例之摻混物,利用微分掃描熱卡計(DSC) 、動態機械分析儀(DMA) 、偏光顯微鏡(POM) 、熱重損失分析儀(TGA) 、掃描式電子顯微鏡(SEM),藉此觀察各比例摻合體的結晶特性、玻璃轉移溫度(Tg點) 、結晶區之結晶型態及相容性。動態機械分析儀(DMA)觀察摻合物的Tg,發現只有一個Tg點,推測兩相可能為相容或是部分相容,同時PTT加入的含量越多,摻合物的Tg點會隨著含量而微幅下降。偏光顯微鏡(POM)觀察到在少量PTT(10~20%)加入到PLA後,可以促使PLA產生結晶行為。微分掃描熱卡計(DSC)研究分成非等溫結晶與等溫結晶兩部分,非等溫分析發現PTT為20%時,PLA端的結晶放熱峰開始出現,30%有最大值,其結晶度與結晶速率隨著PTT的增加而呈現先升後降的趨勢,與POM分析有相似結果;並且使用Avrami euation分析摻合體在等溫結晶時的結晶情形,分析結果發現在摻合物中PTT的n值約在2.3~2.7左右。接著利用Hoffman-Weeks方法預測各摻混系統的平衡熔點。熱重損失分析儀(TGA)結果顯示隨PTT含量增加,Td點開始下降。掃描式電子顯微鏡(SEM)觀察在酯交換分析上,發現兩相相容的情形發生。
In this study, organic environmental polymer (PLLA ) and new-type textile polymer (PTT ) were studied. PLLA was the continuous phase and PTT was the dispersed phase. 10~50%(wt%) PTT was added to PLA solution. The crystallization behavior, glass transition temperature, morphology and miscibility of poly(L-lactic acid)/ Poly(Trimethylene Terephthalate) blends were investigated using differential scanning calorimetry(DSC), dynamic mechanical analyzer(DMA), polarized-light microscopy(POM), thermal gravimetric analysis(TGA), and scanning electron microscopy(SEM). DMA results show only one Tg, which could infer that the blends is miscible or partially miscible. The more PTT is added, the lower Tg of these blends are. Under POM, we observe that small amount of PTT (10~20%) can promote the crystallization of PLA. DSC study can be divided into nonisothermal and isothermal-crystallization. From nonisothermal analysis, We find when PTT is 20wt%, crystallization peak of PLA starts to appear. When PTT is 30%, the peak shows maximum. The degree of crystallinity and rate of crystallization first rise and then fall with the increase of PTT. POM shows similar results. The isothermal crystallization behavior could be analyzed using Avrami equation. We find the n value of PTT is about 2.3~2.7 in these blends. Hoffman-Weeks method can predict the equilibrium melting point of each blend. TGA result shows Td will fall down when PTT content increases. Finally, SEM analysis verifies that PLA and PTT is miscible.