本研究以生物可分解高分子聚乳酸為基材與陶瓷材料氮化鋁製備導熱複材，並以兩種不同增韌劑提升高分子複材之機械性質，以熔融混煉法及熱壓成型法製備複材。探討氮化鋁添加比例10 phr、20phr及30phr對於導熱係數之影響；更討論不同增韌劑對於複材之各種影響，包括拉伸性質、耐衝擊性質、顯微結構、熱性質及導熱之測試。
由拉伸測試及耐衝擊測試可得知，聚乳酸為一種硬且脆的材料，而氮化鋁的添加會使得複合材料脆性提升，當以少量POE和mPOE為增韌劑時，有效提升複材之斷裂伸長量及耐衝擊強度，尤其以mPOE影響較為明顯；可由SEM顯微結構觀察出，mPOE與聚乳酸之相容性較佳，故對機械性質影響較佳；由熱性質分析則可發現，增韌劑和氮化鋁的添加使得聚乳酸結晶性下降；利用流變測試，複材的儲存模數會因增韌劑的添加而下降，表示其流動性較高，而氮化鋁含量增加，儲存模數會逐漸上升，代表複材的剛性提升了。由導熱分析結果可得知，導熱度會隨著氮化鋁含量增加而提升，相較於純聚乳酸基材，複材添加30phr的氮化鋁時導熱度提升了46%。 In this study, we aimed at enhancing thermal conductivity of polymer composites. We use biodegradable polymer poly(lactic acid) to be the matrix and the ceramic powder aluminum nitride to be the filler. And we use two kinds of polyolefin to improve mechanical properties.We use blender and hot press method to produce our samples. The result was analyzed by tensile test, impact test, DSC, SEM and thermal conductivity.
We found poly(lactic acid) is a hard and brittle materials form tensile test and impact test. The addition of aluminum nitride made composites more brittle. So we used POE and mPOE as toughener. It will improve elongation at break and impact strength, especially mPOE. Morphology of PLA/POE and PLA/mPOE composites were investigated by SEM, PLA and mPOE are compatible slightly. The degree of crystallization and melt temperature of blends were observed by differential scanning calorimetry (DSC). The results indicate the addition of elastomer or aluminum nitride decrease the degree of crystallization. Rheological properties were tested by plate to plate rheometer. The addition toughner made storage modulus decreased. Because of composites are softer than neat PLA. However more aluminum nitride made storage modulus increased. PLA/AlN composites become rigid. Thermal conductivity of PLA/AlN increased with AlN content increased. Compare with neat PLA, thermal conductivity of PLA/AlN 30 phr composite increase 46%.
