近年來，聚乳酸(PLA)受到產業界的重視，認為聚乳酸為最有前途的聚合物材料，原因在於聚乳酸物性佳、生物可分解性、生物相容性良好，以及其原料為乳酸，可由玉米、小麥等作物中獲取，因此可減少二氧化碳的排放量、減緩溫室效應，且對於環境的污染小。但由於聚乳酸本身的耐熱性差以及高溫加工易水解。因此本研究以ADVN為起始劑、己內醯胺為保護基進行活性自由基聚合，合成Styrene-MMA-GMA三團鏈式共聚合物，以FTIR以及1H-NMR方式確認其結構，並將所合成出的三團鏈式共聚物當作聚乳酸的鏈延長劑，將鏈延長劑與聚乳酸在200℃進行熔融混摻，用以解決聚乳酸在高溫易水解以及耐熱性差的問題。從GPC的分析結果可以得知添加鏈延長劑可將聚乳酸的重量平均分子量從108,000上升至272,000，藉此改善聚乳酸高溫水解的問題，以XRD、DSC、POM分析中證實添加鏈延長劑能可誘導聚乳酸的結晶，使成核點變多、結晶更為緊密、結晶速率提升、結晶度從18.3%提升至51.6%，最後從拉伸試驗、衝擊試驗、DMA中得知鏈延長劑能有效可將聚乳酸的延伸率從7.7%提升至44.4%，衝擊能量可從0.38(J/cm2)提升至0.45(J/cm2)，儲存模數從1,720提升至5,190，改善PLA的物性以及耐熱性。

Poly(lactic acid) (PLA) by the industry’s attention. PLA as the most promising polymer materials. The reason is that the good properties of PLA, and PLA is one kind of biodegradable aliphatic polyester. PLA raw material for lactic acid, obtained from corn, wheat and other crops. Reduce carbon dioxide emissions, mitigation of greenhouse, and small for environmental pollution. However, poor heat resistance and high high temperature processing of PLA is easily hydrolyzed. Preparation of Styrene-MMA-GMA tirblock copolymer using the ADVN as initiator and Caprolactam as the capping agent for Living-Free-Radical-Polymerization. From the FTIR and 1H-NMR results, confirmed the structure. Triblock-copolymer as chain extender in PLA, Chain extender and PLA melt blend at 200℃.From the GPC results, the molecular weight of polymer increased to 272,000 with the Chain extender and PLA melt blend, to improve the PLA high-temperature hydrolysis. From XRD, DSC and POM results, crystalline of PLA increased to 51.6% with the Chain extender and PLA melt blend. Finally, from Tensile test, Impact test, DMA result, the elongation of PLA increased to 44.4%, the impact energy of PLA increased to 0.45(J/cm2), the storage modulus of PLA increased to 5,190, enhance the physical properties and heat resistance of PLA.

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