| 摘要: | 聚酯類化合物PCL和PLA是常見的內酯開環聚合產物由於其良好的生物相容性且易於降解的特性，已被廣泛應用於包裝材料及醫療用途使用。鹼土族金屬有較低的毒性、容易取得且價格便宜，適合作為催化劑在開環聚合領域中已被廣泛的使用。本研究使用鹼土族金屬 (Mg, Ca, Sr) 催化劑，在室溫下進行開環聚合反應，在加入苯甲醇作為起始劑，使催化劑在反應過程中原位生成鹼土金屬苯甲醇鹽，可以在極短的時間 (1分鐘) 內對ε-己內酯 (ε-CL)、δ-戊內酯 (δ-VL) 及 (10分鐘) 丙交酯 (L-LA) 完成單體的開環 (轉化率 > 90 %)，獲得分散性良好的PCL (最佳Đ 1.39)、PVL (最佳Đ 1.16)及PLA (最佳Đ 1.09)。我們進行了聚合反應動力學的研究，對於這些內酯單體濃度皆為二級反應，並且反應速率方面PCL Mg < Ca < Sr，而PLA Ca < Sr < Mg。這些研究成果皆顯示鹼土族金屬催化劑在溫和的條件下對開環聚合反應有優秀的催化活性，並使聚合反應保持在良好的控制下。;Polyester such as PCL and PLA are common products of lactone ring-opening polymerization. Due to their good biocompatibility and ease of degradation, they have been widely used in packaging materials and medical applications. Alkaline earth metals, which have lower toxicity, are readily available, and inexpensive, suitable as catalysts and have been widely used in the field of ring-opening polymerization. In this study, we used alkaline earth metal (Mg, Ca, Sr) catalysts to conduct ring-opening polymerization reactions at room temperature. By adding benzyl alcohol as an initiator, the catalysts generated alkaline earth metal benzyl alkoxide during the reaction. This method allowed the ring-opening of ε-caprolactone (ε-CL), δ-valerolactone (δ-VL), and (within 10 minutes) L-lactide (L-LA) , respectively to be completed in an extremely short time (1 minute), achieving conversion rates of over 90%. The resulting polymers exhibited narrow dispersity: PCL (optimal Đ 1.39), PVL (optimal Đ...), and PLA (optimal Đ 1.09). We conducted a kinetic study of the polymerization reactions, finding that the concentration of these lactone monomers followed second-order kinetics. The reaction rates were PCL Mg < Ca < Sr and PLA Ca < Sr < Mg. These research results demonstrate that alkaline earth metal catalysts exhibit excellent catalytic activity under mild conditions for ring-opening polymerization reactions and maintain good controlled polymerization. |
