| 摘要: | 為了降低以石油為原料的傳統塑膠對環境所帶來的負面影響，生物可分解塑膠的發展逐漸受到重視，由於它對環境的友善性，故被應用在許多日常生活用品上，而聚乳酸(Poly(lactic acid)，PLA)是被應用最廣泛的。本研究以聚乳酸為主材料，首先以十八烯(Octadecene，ODC)與馬來酸酐(Maleic anhydride，MA)兩反應物在高溫下(200C)進行烯-烯反應(Ene-reaction)，得到的產物為十八烯基琥珀酸酐(Octadecenylsuccinic anhydride，ODSA)，之後以混煉機製備出PLA/ODSA摻合物，希望ODSA能當作塑化劑，並且能增加PLA之韌性，由於ODSA結構上帶有碳長鏈基團，質地較為柔軟，故另外比較PLA與蒙托土(Closite Na+)或市售改質蒙托土(Cloisite 30B)摻合物之機械性質，選定其中一個最佳比例，再將自行合成ODSA添加於其中，最後，以Proteinase K酵素進行生物分解實驗。實驗結果顯示ODSA的添加確實能塑化PLA，當ODSA添加含量為5 phr，降伏強度開始出現，斷裂伸長率由原本的3.15 %增加至7.59 %，當ODSA的添加量增加至10 phr，斷裂伸長率更增加至15.08 %，此外，不管是添加蒙托土或市售改質的蒙托土，均可增加PLA之楊氏模數，當PLA加入5 phr的Closite Na+時，斷裂強度由原先的38.9 MPa可增加至47.7 MPa，但是斷裂伸長率降至3.07 %，將ODSA加入於PLA/Closite Na+-5 phr摻合物當中，當ODSA添加含量為7 phr時，斷裂伸長率可增加至6.72 %，而楊氏模數亦可增加至1.47 GPa。由生物分解實驗當中發現，隨著ODSA的添加含量增加至5 phr、7 phr，經過7天後，其重量損失率從PLA的42.6 %分別下降至37.2 %和35.9 %，顯示ODSA的添加會使得PLA/ Closite Na+/ODSA摻合物被Proteinase K酵素分解的能力下降，推測為結晶度增加和疏水性增加之緣故。
In order to reduce negative influence, which brings the environment into contamination, of traditional plastics made from petroleum, more attention has been paid on development of biodegradable polymers due to its friendless to the environment, so it is used in many daily necessities. PLA is most widely used as well as main material of my study. Firstly, octadecenylsuccinic anhydride (ODSA) was obtained by ene-reaction between octadecene (ODC) and maleic anhydride (MA) at high temperatures ( 200C). Then we prepare PLA/ODSA blends by mixer, hoping ODSA can act as an plasticizer, and it can increase the toughness of the PLA, due to the long carbon chain group on its structure, having soft texture, in order to fix this point, we compare the mechanical property of PLA/Cloisite Na+blends and PLA/Cloisite 30B blends, selectingone of the best proportion from them, then ODSA is added to to this. Finally, we do the enzymatic degradation for films by proteinase K. Experimental results show that PLA is plasticized by the addition of ODSA, yield strength appears when its content is 5 phr, elongation at break increased from 3.15 % to 7.59 %, when its content increased to 10 phr, elongation at break even increased to 15.08 %, in addition, montmorillonite(Cloisite Na+) or montmorillonite modified commercially (Cloisite 30B)both can increase the initial modulus of PLA, when the content ofCloisite Na+ is 5 phr, break strengeh increased originally from 38.9 MPa to 47.7 MPa, but elongation at break decreased to 3.07 %, we add ODSA to the PLA/Cloisite Na+ -5 phr blends, when ODSA contnet is 7 phr, elongation at break increased to 6.72 %, while initial modulus also increased to 1.47 GPa. On the other hand, it is found that the content of ODSA increased to 5 and 7 phr, the weight loss percentage of PLA films are dropped from 42.6 % to 37.2 % and 35.9 % respectively from biological decomposition experiment after 7 days, showing the biodegradability of PLA/Cloisite Na+/ODSA blends is lower than the PLA films by proteinase K when the ODSA is added, presuming the degree of the crystallinity and hydrophobicity increased. |
