三亚甲基环碳酸酯及2,2-二甲基三亚甲基环碳酸酯开环均聚合*

生物降解聚合物聚三亚甲基环碳酸酯（PTMC）及聚2,2-二甲基三亚甲基环碳酸酯（PDTC）在药物控释载体及其它生物医学技术领域有着良好的应用前景。与脂肪族聚酯不同,PTMC、PDTC降解时,不会产生有害的酸性化合物。PTMC、PDTC主要由三亚甲基环碳酸酯（TMC）及2,2-二甲基三亚甲基环碳酸酯（DTC）开环均聚合制备。本文总结了催化TMC、DTC开环均聚合的不同催化剂及其聚合机理,综述了近年来国内外在TMC、DTC均聚合催化剂开发上的研究进展,并对生物相容性催化剂如稀土催化剂、Ca、Mg、Zn、Fe催化剂以及酶催化剂催化TMC、DTC开环聚合的优缺点进行了比较。     

有机小分子催化ε-己内酯开环聚合反应

聚己内酯(PCL)是一种生物可降解高分子材料,具有良好的环境、生物相容性,广泛应用于生物医学、包装等领域。有机小分子催化ε-己内酯单体开环聚合反应是制备聚己内酯的主要方式之一。与传统的金属催化相比,有机催化不仅反应条件温和、聚合可控,而且还可解决聚合物中金属残留问题,是目前高分子合成化学的研究热点。本文按照催化体系的不同活化方式,讨论了近年来有机催化在ε-己内酯开环聚合反应中的研究进展,归纳总结了不同催化体系的优缺点,并在此基础上展望了有机小分子催化剂在ε-己内酯开环聚合反应中的发展趋势和应用前景。     

Studies on Ring—Opening Polymerization of Chloromethyl Thiirane with Rare Earth Catalysts and Functional Resins Synthesized therewith

Studies on ring-opening polymerization of chloromethyl thiirane with rare earth catalysts and functional resins synthesized therewith were reviewed.     

环氧乙烷环氧丙烷开环聚合反应动力学研究

环氧乙烷和环氧丙烷由于具有较高的环张力,因而容易发生开环聚合。本文综述了环氧乙烷合环氧丙烷开环聚合反应的动力学研究进展,考察了环氧乙烷和环氧丙烷开环聚合反应的机理,分别讨论了各类催化剂体系中环氧乙烷和环氧丙烷开环聚合的动力学常数、两者的竞聚率及开环聚合产物的分子量分布,并指出了开环聚合反应动力学研究对于环氧乙烷和环氧丙烷的开环聚合研究及工业应用的重要性。     

咪唑鎓离子液体协同催化苯酚与碳酸丙烯酯的反应

在离子液体1-丁基-3-甲基咪唑乙酸盐([bmim]OAc)催化下,苯酚和碳酸丙烯酯一步合成了丙二醇苯醚.系统考察了反应温度、反应时间及催化剂用量对反应性能的影响,在优化的反应条件下,丙二醇苯醚的收率达79%.同时研究了不同咪唑鎓离子液体的阴阳离子的种类对催化反应的影响,发现咪唑鎓中的C2-H对反应有极大的促进作用,咪唑鎓通过提供氢键能力活化反应底物碳酸丙烯酯;同时,离子液体的阴离子也对反应有很大的影响,阴离子通过接受氢键能力活化另一反应底物苯酚.离子液体阴阳离子通过提供和接受氢键协同催化苯酚与碳酸丙烯酯的反应.离子液体循环使用5次,其活性未见明显降低.     

含负氢配体的单核钌催化的降冰片烯开环易位聚合催化研究

设计的含负氢配体的单核钌配合物Ru(p-cymene)HClPCy₃高活性地催化了降冰片烯开环易位聚合反应(ROMP), 并通过设计的Ru(p-cymene)H₂PCy₃对降冰片烯的催化活性研究证明了单核催化剂需同时含有氯原子配体, 提出了反应机理.     

稀土席夫碱配合物催化己内酯可控开环聚合

 通过稀土氯化物与席夫碱钠盐的交换反应制备了一系列以 3,5-二叔丁基水杨醛缩苯胺为配体的稀土席夫碱配合物. 对其中的钕席夫碱配合物进行了 X射线单晶衍射分析, 发现其单晶结构为五角双锥构型, 所得席夫碱稀土配合物可以单组分催化 ?-己内酯开环聚合. 深入研究了钕席夫碱配合物催化己内酯的开环聚合机理, 考察了不同聚合条件对单体转化率、产物分子量及分子量分布的影响. 结果表明, 该聚合反应速率为一级, 聚合反应具有较好的可控性. 聚合物端基分析表明, 聚合反应以配位-插入机理进行.     

A Study of L-Lactide Ring-Opening Polymerization Kinetics

Summary: The paper presents an experimental study of L-lactide polymerization in molten state using as initiator the Stannous Octoate. The experiments were performed in a Haake mixer. The operating temperatures were between 170 and 195°C, the reaction time up to 60 min and monomer to initiator initial molecular ratio between 10² and 5 · 10³. The conversion was determined by using ¹H NMR and the molecular weights distributions by SEC. A preliminary mathematical modeling study was also performed, based on experimental data and a previously published reaction scheme.     

Cationic Ring-Opening Polymerization of 1,3-Dehydroadamantanes

Ring-opening polymerizations of [3.3.1]propellane derivatives, 1,3-dehydroadamantane ( 1 ) and 5-butyl-1,3-dehydroadamantane ( 2 ), were carried out with CF₃SO₃H in CH₂Cl₂ at 0 °C for 6–42 h. The central σ-bonds in 1 and 2 were exclusively opened to afford novel poly([3.3.1]propellane)s, poly(1,3-adamantane)s, in 52–95% yields. The resulting poly( 2 ) possessing flexible butyl substituent was soluble in chloroform, THF, and 1,2-dichlorobenzene, and the degree of polymerization was estimated to be greater than 30, while the poly( 1 ) was hardly soluble in the common organic solvents. All aliphatic poly( 1 ) and poly( 2 ) showed high thermal stability, their 10% weight loss temperatures were 421 and 486 °C, respectively.     

开环易位聚合合成瓶刷聚合物

瓶刷聚合物是一类具有独特侧链结构的梳形聚合物。功能性瓶刷聚合物在光子晶体、表面活性剂、医药载体、防污涂层以及智能材料等领域具有良好的应用价值。通过开环易位聚合合成瓶刷聚合物的方法具有合成步骤简单、聚合物接枝密度高和侧链组成均一等优点,在控制聚合物组成、分子量和分散性等方面具有显著优势。本文基于开环易位聚合,简述了合成瓶刷均聚物以及嵌段型、混合型和核-壳型三种类型的瓶刷共聚物的方法,并介绍了合成精确结构的瓶刷聚合物的新进展。     

Living Ring-Opening Polymerization of Cyclic Esters with Epoxide-Derived Titanium Alkoxides

Summary: The Ti^IIICp₂Cl-catalyzed radical ring opening of epoxides produces Ti alkoxides which initiate the ring-opening polymerization of ε-caprolactone. A linear dependence of on conversion, linear kinetics, low values, and the synthesis of block copolymers demonstrate a living process, while NMR spectroscopy confirms the presence of the initiator chain end. Epoxides are thus introduced as a new class of initiators for the Ti-catalyzed living ring-opening polymerization of cyclic esters.

The TiCp₂Cl-catalyzed radical ring opening of epoxides followed by the initiation of the living ring-opening polymerization of ε-caprolactone.     

Ring-Opening Polymerization of Cyclic Monomers with Aluminum Triflate

A green method for the controlled synthesis of aliphatic polymers is presented. The ring-opening polymerizations of cyclic monomers including several lactones, such as caprolactone (CL) or pentadecalactone (PDL), and cyclic anhydride monomers, such as succinic anhydride (SUC) and tetrahydrofuran (THF), catalyzed by a series of metal triflates (trifluoromethanesulfonate) were studied. Aluminum triflate was found to be an advantageous candidate to catalyze the ring-opening polymerization of cyclic monomers. The details of the ring-opening polymerization of CL catalyzed by aluminum triflate were studied. The maximum number average molecular weight (M_n), polydispersity (M_w/M_n) and yield of the obtained poly(-caprolactone) (PCL) at 60 °C for 6 hours were 18,400, 1.94 and 89 wt%, respectively. Those of poly(pentadecalactone) (PPDL) at 100 °C for 6 hours were 12,400, 2.24 and 49 wt%, respectively. The M_n, M_w/M_n and yield of the obtained poly(butylene succinate) (PBS) from SUC and THF at 100 °C for 48 hours were 4,900, 2.03 and 84 wt%, respectively. Furthermore, the mechanism of the polymerization was discussed based on the relationship between the conversion of CL and time. The molecular weight buildup of PCL was linear with a conversion in 50 min before the conversion reached 100 % and with M_w/M_n stabilized at about 1.5. The M_w/M_n of PCL then gradually increased. From these data, a living polymerization with a small transesterification was suggested from the PCL polymerization by aluminum triflate.     

开环聚合接枝改性木质素

作为自然界储量丰富的生物质资源之一,木质素尚未得到充分利用,成为掣肘生物化工发展的挑战。利用木质素丰富的功能基团进行接枝聚合改性,已成为木质素高值化利用的一个重要途径。开环聚合是一种温和、高效的聚合方法,可以将脂肪族聚酯链段引入到木质素中,提高材料的溶解性、相容性和可降解性,拓展木质素的应用范围。本文关注多催化条件下丙交酯、己内酯等环状单体通过开环聚合对木质素进行接枝改性的研究进展,同时对木质素改性材料的性能、应用以及发展前景进行了探讨。     

A Novel Construction of Ring-Opening Polymerization and Chemical Recycling System

This article summarizes our recent efforts to chemical recycling of polymeric materials based on the equilibrium polymerization character of cyclic monomers. Spiro orthoesters ( SOE s), bicyclo orthoester, cyclic carbonates, and dithiocarbonates undergo ring-opening polymerization to afford the corresponding polymers, and the resulting polymers depolymerize to give the starting monomers under cationic or anionic conditions. Further, crosslinking and decrosslinking systems of bifunctional SOE s and a polymer having SOE moiety in the side chain are described.     

NMP与ROP相结合制备PCL-b-PSt共聚物及其性能研究

以4-羟基-2,2,6,6-四甲基哌啶氮氧自由基（HTEMPO）为引发剂,通过ε-己内酯（ε-CL）的开环聚合,合成末端基为氮氧自由基的聚己内酯（PCL-T）。在其调控下,进行过氧化苯甲酰（BPO）引发苯乙烯（St）的自由基聚合,合成结构规整的聚己内酯-b-聚苯乙烯（PCL-b-PSt）共聚物。用氢核磁共振（1H-NM...     

RING-OPENING POLYMERIZATION OF TRIMETHYLENE CARBONATE CATALYZED BY NOVEL SINGLE COMPONENT RARE EARTH CALIXARENE COMPLEXES

In this paper, ring-opening polymerization of trimethylene carbonate (TMC) with rare earth (Nd, Y, La) p-tert-butylcalix[n]arene (n=4, 6, and 8) complexes as catalysts has been studied. Poly(trimethylene carbonate) (PTMC) with Mv of 21,400 was produced by bulk polymerization under the conditions as follows: [TMC]0/[Nd] (molar ratio)=1000,80℃,8h. Mechanism study reveals that the polymerization proceeds via a coordination mechanism.     

Effect of two Kinds of Imidazolium Ionic Liquids on the Microemulsion Polymerization of Methyl methylacrylate

Summary: In this paper, the microemulsion polymerization of methyl methylacrylate (MMA) was carried out with single and gemini ionic liquids as emulsifier including 1-N-tetradecyl-3-methylimidazolium bromide (C₁₄MIM · Br) and 1, 4-Bis (3-tetradecylimidazolium-1-yl) butane bromide (C₁₄MIM-4-C₁₄MIM · 2Br) respectively, and they were all have typical microemulsion polymerization characters of MMA, but the process of polymerization directly depends on the structure of the imidazolium ionic liquids. The structure and concentration of ionic liquids have effects on the resulted latex particle sizes of PMMA, and much smaller size latexes of PMMA could be gotten with C₁₄MIM · Br as emulsifier than C₁₄MIM-4-C₁₄MIM · 2Br in polymerization. On the other hand, the structure of emulsifier has the effects on the molecular weight (MW) and molecular weight distribution (MWD) of PMMA, so the resulting PMMA prepared from microemulsion polymerization with C₁₄MIM · Br as emulsifier has higher MW but narrower MWD than that of PMMA with the same dosage of C₁₄MIM-4-C₁₄MIM · 2Br as emulsifier.     

Ring-Opening Polymerization of L-Lactide in Supercritical Chlorodifluoromethane

The ring-opening polymerization of L -lactide initiated by 1-dodecanol/stannous 2-ethylhexanoate (DoOH/Sn(Oct)₂) was carried out in supercritical chlorodifluoromethane at various reaction times, pressures, and temperatures. The monomer conversion increased to ca 70 % on increasing the reaction time to 25 h. The molecular weight of the product also increased to ca 75,000 g/mol over the same period. Increasing the pressure resulted in an accelerated polymerization rate. The pressure-induced increase in the rate of L -LA polymerization can be explained by the formation of chemical bonds in the transition state, which implies the production of a transition state with a lower partial molar volume than the reactants.