【摘要】：脂肪族聚酯以其良好的生物相容性、生物可降解性和滲透性在各領(lǐng)域有著重要的應(yīng)用,如包裝、生物材料、藥物載體、醫(yī)療設(shè)備等。合成脂肪族聚酯最有效的方法是金屬配合物催化的開環(huán)聚合,該方法合成的聚合物分子量可控,分子量分布窄。其中,外消旋丙交酯聚合物作為一類重要的脂肪族聚酯,其物理化學(xué)性能與自身的立體結(jié)構(gòu)有很大的關(guān)系,合成具有理想立體構(gòu)型的聚丙交酯成為研究的焦點(diǎn)。近年來(lái),堿金屬催化劑引起了廣泛的興趣,其中類似夾心結(jié)構(gòu)的堿金屬配合物表現(xiàn)出良好的催化效果。本文合成和表征了多種堿金屬配合物,研究它們對(duì)rac-LA開環(huán)聚合的催化性能,主要內(nèi)容如下:第一章介紹了各種金屬體系催化環(huán)酯開環(huán)聚合的研究進(jìn)展,其中詳細(xì)介紹了堿金屬催化體系的發(fā)展過程和現(xiàn)狀。第二章介紹了以冠醚為輔助配體,手性及非手性單酚負(fù)離子穩(wěn)定的鈉和鉀配合物的合成、表征及催化rac-LA開環(huán)聚合作用。在BnOH存在下,配合物能有效催化rac-LA開環(huán)聚合,聚合物分子量可控,分子量分布較窄,同時(shí)有較高的選擇性。改變單酚位阻的大小,對(duì)催化劑的性能影響較大;而當(dāng)利用手性及非手性的單酚作為配體時(shí),兩者具有相同的立體選擇性。第三章介紹了以冠醚為輔助配體,8-羥基喹啉衍生物穩(wěn)定的鉀配合物的合成、表征及催化rac-LA開環(huán)聚合作用。配體上的取代基對(duì)催化劑的活性影響較大,帶強(qiáng)吸電子基團(tuán)的配體會(huì)降低催化劑活性,甚至使催化劑失活。鉀配合物3.1在催化rac-LA開環(huán)聚合中表現(xiàn)出良好的性能,常溫下聚合物的Pm值達(dá)到0.72,而在0℃時(shí)Pm值達(dá)到0.75。第四章介紹了以冠醚為輔助配體,水楊醛亞胺穩(wěn)定的鈉和鉀配合物的合成、表征及催化rac-LA開環(huán)聚合作用。水楊醛亞胺配體并沒有采用雙齒配位的形式與堿金屬絡(luò)合,而是采用單酚氧配位的形式。配合物在常溫下能高效催化rac-LA開環(huán)聚合,其中鉀配合物4.4的催化選擇性最高,在0℃時(shí)聚合物的Pm值達(dá)到0.75.第五章介紹了以手性冠醚為輔助配體,大位阻單酚負(fù)離子穩(wěn)定的鈉和鉀配合物的合成、表征及催化rac-LA開環(huán)聚合作用。在BnOH存在下,配合物能高效催化rac-LA開環(huán)聚合,聚合物的分子量可控,分子量分布窄。但與傳統(tǒng)冠醚螯合的堿金屬配合物比較時(shí),其催化反應(yīng)的選擇性并沒有提高。另外,還探究了不同的共引發(fā)劑對(duì)rac-LA開環(huán)聚合的影響。
[Abstract]:Aliphatic polyester has important applications in many fields for its good biocompatibility biodegradability and permeability such as packaging biomaterials drug carriers medical equipment and so on. The most effective method for the synthesis of aliphatic polyester is the ring-opening polymerization catalyzed by metal complexes. The molecular weight of the polymer synthesized by this method is controllable and the molecular weight distribution is narrow. As a kind of important aliphatic polyester, the physical and chemical properties of racemic lactide polymer are closely related to its stereoscopic structure. The synthesis of poly (lactide) with ideal stereotype has become the focus of research. In recent years, alkali metal catalysts have attracted wide interest, among them, alkali metal complexes with similar sandwich structure show good catalytic effect. In this paper, a variety of alkali metal complexes have been synthesized and characterized, and their catalytic properties for rac-LA ring-opening polymerization have been studied. The main contents are as follows: in Chapter 1, the research progress of cycloester ring-opening polymerization catalyzed by various metal systems is introduced. The development process and present situation of alkali metal catalytic system are introduced in detail. In chapter 2, the synthesis, characterization and catalytic ring-opening polymerization of rac-LA with chiral and non-chiral monophenol anion stabilized sodium and potassium complexes with crown ether as auxiliary ligands were introduced. In the presence of BnOH, the complexes can effectively catalyze the ring-opening polymerization of rac-LA, the molecular weight of the polymer is controllable, the molecular weight distribution is narrow and the selectivity is high. When the chiral and non-chiral monophenols were used as ligands, they had the same stereoselectivity. In chapter 3, the synthesis, characterization and rac-LA ring-opening polymerization of stable potassium complexes with crown ethers as auxiliary ligands were introduced. The activity of the catalyst was greatly affected by the substituents on the ligands. The combination of the strong electron-absorbing groups decreased the activity of the catalysts and even deactivated the catalysts. Potassium complex 3.1 shows good performance in the ring-opening polymerization of rac-LA. The pm value of the polymer reaches 0.72 at room temperature and 0.75 at 0 鈩，

本文編號(hào)：2176439