本文選題：開環(huán)聚合 + 鈉配合物�。� 參考：《中國科學(xué)技術(shù)大學(xué)》2017年碩士論文

【摘要】：近年來,生物可降解聚合物一直受到人們的廣泛關(guān)注,其中,脂肪族聚酯由于具有良好的生物相容性、生物降解性以及優(yōu)越的機(jī)械性能而備受關(guān)注。合成脂肪族聚酯的原料來源廣泛,且得到的聚合物具有分子量可控、分子量分布窄等優(yōu)點,已被廣泛應(yīng)用于手術(shù)縫合線、口腔植入物、藥物載體、基因載體、組織工程、組織支架等領(lǐng)域。聚丙交酯(PLA)作為一種重要的生物可降解聚合物,其合成原料可從玉米、甜菜等自然作物中獲得,并且最終降解為對環(huán)境無污染的CO2和H2O,因此具備廣闊的應(yīng)用前景。金屬催化環(huán)酯開環(huán)聚合是合成聚丙交酯的一種有效方法,研究出高效的金屬配合物催化劑具有重要的應(yīng)用價值,這也是近年來該領(lǐng)域的研究熱點。本論文合成和表征了各種配體配位的鈉、鉀配合物,研究它們在選擇性催化外消旋丙交酯(rac-LA)開環(huán)聚合中的作用,并對催化劑結(jié)構(gòu)和丙交酯的催化活性及立體選擇性的關(guān)系進(jìn)行了討論。主要內(nèi)容如下:第1章介紹了生物可降解材料的發(fā)展背景和金屬催化丙交酯開環(huán)聚合的機(jī)理以及聚丙交酯的立體結(jié)構(gòu);并分類介紹了各種金屬體系(鋁、鈣、鎂、鋅以及堿金屬等)催化丙交酯開環(huán)聚合的研究進(jìn)展。第2章介紹了 N,N-雙齒配體配位的鈉、鉀配合物的合成、表征及催化rac-LA開環(huán)聚合。研究發(fā)現(xiàn):在芐醇(BnOH)存在的條件下,此類鈉和鉀的絡(luò)合物都能有效地催化rac-LA開環(huán)聚合,且活性相當(dāng)高。聚合反應(yīng)在較低單體催化劑比例時可控性很好,繼續(xù)增大單體催化劑比例,聚合向著不可控方向發(fā)展。增大BnOH比例,聚合反應(yīng)可控性增加;降低反應(yīng)溫度,催化劑催化聚合的立體選擇性提高,-60 ℃條件下得到了 Pm值為0.66的聚丙交酯。第3章介紹了一系列2-苯并三唑取代的酚氧配體和冠醚為輔助配體配位的鈉、鉀配合物,在BnOH存在的條件下,這些配合物都能立體選擇性地催化rac-LA開環(huán)聚合,且催化活性相當(dāng)高。溶劑、單體催化劑比例以及溫度都對催化劑催化rac-LA的立體選擇性影響很大。當(dāng)溫度由20℃C降低到60℃時,Pm值由0.61增加到0.77。在甲苯中聚合,得到等規(guī)取向的PLA,而在CH2Cl3和THF中聚合,得到雜規(guī)取向的PLA。
[Abstract]:In recent years, biodegradable polymers have been widely concerned. Among them, aliphatic polyester has attracted much attention because of its good biocompatibility, biodegradability and excellent mechanical properties. The synthetic aliphatic polyester has been widely used in surgical suture, oral implants, drug carriers, gene carriers, tissue engineering and so on for its advantages of controllable molecular weight and narrow molecular weight distribution. Tissue scaffolds and other fields. Poly (lactide), as an important biodegradable polymer, can be synthesized from natural crops such as maize and beet, and finally degraded to CO2 and H _ 2O, which has no pollution to the environment, so it has a broad application prospect. Metal catalyzed ring opening polymerization of cycloesters is an effective method for the synthesis of poly (lactide). The study of metal complex catalysts has important application value, which is also a hot research field in recent years. In this paper, the coordination of various ligands with sodium and potassium complexes was synthesized and characterized. The role of these complexes in selective ring-opening polymerization of rac-lactide rac-LAs was studied. The relationship between catalyst structure, catalytic activity and stereoselectivity of lactide was discussed. The main contents are as follows: in Chapter 1, the development background of biodegradable materials, the mechanism of metal-catalyzed ring-opening polymerization of lactide and the stereoscopic structure of poly (lactide) are introduced. Zinc and alkali metals) as catalysts for ring-opening polymerization of lactide. In chapter 2, the synthesis, characterization and catalytic rac-LA ring-opening polymerization of sodium and potassium complexes coordinated by N-N-didentate ligands were introduced. It is found that in the presence of benzyl alcohol BnOH, the complexes of sodium and potassium can effectively catalyze the ring-opening polymerization of rac-LA, and their activity is quite high. The polymerization has good controllability when the ratio of monomer catalyst is low, and the polymerization is uncontrollable with increasing the ratio of monomer catalyst. When the ratio of BnOH was increased, the controllability of polymerization was increased, and the stereoselectivity of catalyst was increased by decreasing the reaction temperature. The poly (lactide) with pm value of 0.66 was obtained under the condition of increasing the ratio of BnOH and the stereoselectivity of the catalyst. In chapter 3, a series of 2-benzotriazole-substituted phenoxy ligands and sodium and potassium complexes with crown ether as auxiliary ligands are introduced. In the presence of BnOH, these complexes can stereoselective catalyze the ring-opening polymerization of rac-LA. And the catalytic activity is quite high. Solvent, monomer ratio and temperature have great influence on the stereoselectivity of rac-LA. When the temperature is reduced from 20 鈩，

本文編號：1797601