- 學位論文
以PEG為主之溫敏性共聚合物及形狀記憶聚氨酯材料之合成與性質之研究
Studies on preparation and properties of thermosensitive copolymers and shape memory materials based on polyethylene glycol
摘要
Part I 本研究是以辛酸亞錫為催化劑，甲氧基聚乙二醇或聚乙二醇為共催化劑，進行乳酸-甘醇酸開環聚合，合成一系列無毒性、無溶劑性、可注射性之具溫感性之甲氧基聚乙二醇(mPEG)/聚乳酸(LA)-甘醇酸(GA)雙團聯共聚物(mPEG-PLGA)，再將此共聚物以2, 2-bis(2-oxazoline)(Box)封端。本研究主要探討此封端結構對其最低臨界轉移溫度(LCST)、水膠安定性、相的轉變及細胞毒性的影響。實驗結果顯示，當以Box 作封端之後，當共聚物溶解於不同溶劑或藥物中，其LCST會提高，臨界成膠濃度(cgc) 會降低、成膠(Gel Formation)溫度範圍在生理食鹽水、牛清蛋白(BSA)、或葡萄糖(10wt%)溶液中會增加；但降解速度有減緩的現象。保存安定性係將樣品保存於各種不同溫度下，於不同時間測量其重量損失。此係參考市售商品Macro Med之產品，在零下20度保存期限18個月來作比較。 Part II 本研究主要合成具生物可分解性[Polyethylene Glycol (PEG) / Polycaprolactone (PCL)]- polyurethanes 之形狀記憶聚氨酯材料。由於具有生物分解性的PCL較為疏水，將其作為軟鏈搭配由2, 4-toluene diisocyanate (TDI)及鏈延長劑合成的PU為硬鏈所組成之具形狀記憶能力的聚氨酯也呈現疏水性。因此本實驗改變PEG分子量來增加其親水性使其更具生物相容性，並比較由改變軟硬鏈段比例所組成之聚氨酯之性質。本實驗是以FT-IR、DSC及GPC來確認此結構上及分子量的分析，由DSC發現不同的軟硬段比例下，聚氨酯隨著導入硬段的比例上升，硬段在結構中所形成的物理交聯會使的PCL的結晶度下降，進而造成熔點下降。而PEG親水性的增加造成PU材料水接觸角呈現角度降低。而當PCE20系列因為硬鏈的量可以有效形成足夠的物理交聯而使得材料有較高形狀記憶回復率。
並列摘要
Part I In this study, stannous octoate (Sn(Oct)2) as catalyst, methoxy polyethylene glycol or polyethylene glycol as co-catalyst to ring-opening lactide (LA) and glycolide (GA) to synthesize a series of non-toxic, non-solvent, and injectable thermosensitive methoxy polyethylene glycol (mPEG) and poly(lactide-co-glycolide) di-block copolymer (mPEG-PLGA), then this copolymer was end-blocked with 2, 2-bis (2-oxazoline) (Box). The effect of the Box structure in the di-block copolymer on the lower critical transition temperature (LCST), gel stability, phase transition temperature, and cell cytotoxicity of the copolymer was investigated in this study. The results showed that the copolymer’s LCST increased and their critical gelation concentrations (cgc) reduced when the copolymer dissolved in different solutes for the copolymer chain en-capped with Box. The range of gel formation temperature increase when they dissolved in different solutions, such as saline, Bovine Serum Albumin (BSA), or glucose (10 wt%), but their degradation rate would slow down. The stability of storage of the copolymers in different temperatures was measured, in which the commercial products, Macro Med, was referred as its product shelf life duration 18 months when storage in -20 oC of temperature. Part II This research is focus on synthesis of the shape-memory materials based on [polyethylene glycol (PEG) / polycaprolactone (PCL)]-polyurethane (PU) which is biodegradable. Because biodegradable PCL is hydrophobic when we use it as a soft-chain, then combine it with a hard-chain PU which is made from 2, 4-toluene diisocyanate (TDI) and chain-extend agent to synthesize a shape-memory polyurethane, the products will also exhibit hydrophobic. In this article, , we try to change the molecular weight of PEG in the polyethylene glycol (PEG) / polycaprolactone (PCL) to improve the their hydrophilicity and let the products become more biocompatible. Besides, we also compared the properties of polyurethane by changing the composition of soft-chain and hard-chain. The structure and properties and molecular weight of the copolymers were measured with FT-IR, DSC, and GPC. The results showed that when the composition of hard-chain increases, the crystallinity of PCL will decrease because of the physical-crosslink formed by hard-chain in the structure, and then the melting point will be decreased. In addition, the water contact angles of the [(PEG-PCL)-PU] di-block copolymers decrease with increase of the hydrophilic PEG. PCE20 series copolymers have better shape-memory recovered ratio because the amount of hard-chain can effectively form enough physical-crosslink.