FTIR研究聚碳酸亚丙酯型聚氨酯反应动力学

脂肪族聚碳酸酯型聚氨酯大多是由酯交换或环状碳酸酯开环聚合而得的聚碳酸酯合成的，直接用ＣＯ２共聚物合成聚氨酯弹性体的报道很少。本文采用阴离子配位络合的方法，通过调节聚合，以ＣＯ２与环氧丙烷为单体合成了分子量、官能度可调节的端羟基聚碳酸亚丙酯（ＰＰＣ），...     

大环碳酸酯的Novozym-435酶促开环聚合

研究了14元环的碳酸丁二酯二聚体在固定化脂肪酶Novozym-435催化下的开环聚合反应制备聚碳酸丁二酯.聚合在常压,75℃的甲苯溶液中进行,反应条件温和.详细探讨了反应条件诸如单体浓度,酶浓度对于聚合的影响.结果显示Novozym-435具有与异辛酸亚锡可比拟的高催化活性,同时可以回收重复使用.聚合动力学研究表明碳酸丁二酯的酶促甲苯溶液开环聚合和环状内酯的酶促甲苯溶液聚合有所不同,没有表现出活性聚合的特征.     

亲电缩聚反应合成芳香环状低聚醚酮砜及其开环聚合

"假高稀"条件下,以邻苯二酰氯为酰基化试剂,Lewis碱NMP存在下,通过亲电缩聚反应高产率地合成了2种芳香环状聚醚酮砜低聚物,利用MALDI-TOF-MS,NMR,GPC,FTIR,DSC等手段对环状结构进行了精确的表征.在负离子引发剂联苯双酚钾存在下,环状低聚物3a进行熔融开环聚合,得到了高分子量的线型聚合物,Tg为221.8℃.利用流变仪监测了环状低聚物3a开环聚合过程中的流变行为,结果表明,开环聚合初期的引发阶段,熔融体的黏度低于10Pa.s,随着时间的延长,黏度快速增长,而且低黏度的引发阶段随着引发剂浓度的增加而变短.     

聚三亚甲基碳酸酯的研究进展

聚三亚甲基碳酸酯具有良好的生物降解性能及生物相容性,是一种重要的生物降解医用高分子材料,在生物医用领域具有较大的应用前景。本文结合近年来的研究进展,综述了阳离子开环聚合、阴离子开环聚合、配位聚合、酶促开环聚合以及微波开环聚合等方法在聚三亚甲基碳酸酯制备过程中的应用,总结了聚三亚甲基碳酸酯的分子量与物理性能的关系,并重点讨论了聚三亚甲基碳酸酯的体内外降解性能,详细描述了分子量及脂肪酶对聚三亚甲基碳酸酯降解行为的影响,最后总结了聚三亚甲基碳酸酯在生物医用领域的应用。     

聚(对苯二甲酸-1,3-丙二酯)环状低聚物的合成、表征和开环聚合反应

探索了由对苯二甲酰氯和1,3-丙二醇在“假高稀”条件下合成聚(对苯二甲酸-1,3-丙二酯)(PTT)环状低聚物的可行性.通过柱色谱分离了环状低聚物和线形低聚物;用核磁共振、质谱和元素分析表征了产物的化学结构;用GPC和HPLC研究了不同大小环的分布,发现在本文实验条件下合成的PTT环状低聚物主要由二、三、四、五和七聚体构成,其中环状三聚体含量最多,没有发现环状六聚体的存在.PTT环状低聚物的熔程为92.3～222.6℃,熔融后是无色、透明的低粘度液体.于250℃将PTT环状低聚物分别在辛酸亚锡、1-乙基-3-氯四丁基锡氧烷、钛酸四丁酯和三氧化二锑催化下进行开环聚合反应,制备了特性粘数为0.18～0.49dL/g的聚合物.     

环状对苯二甲酸丁二酯低聚物CBT的研究进展

环状对苯二甲酸丁二酯低聚物CBT作为目前唯一工业化的芳香基环状低聚物,以其超低熔体黏度、边聚合边结晶特性、开环聚合无反应热、无小分子副产物释放等优点受到工业界和学术界的共同关注,尤其是在连续纤维增强复合材料领域得到了广泛应用。本文从CBT的制备方法与聚合机理入手,系统梳理了CBT聚合过程的流变行为、聚合与结晶的关系、结晶形貌、复合材料的制备及应用、基体树脂的脆性机理、纯树脂及复合材料体系增韧方法、边聚合边结晶过程等方面的研究进展,并就存在的问题进行了展望,对CBT及其它芳香基环状低聚酯研究及应用具有指导意义。     

聚（对苯二甲酸—1，3—丙二醛）环状低聚物的合成、表征和开环聚合反应

探索了由对苯二甲酰氯和1，3－丙二醇在“假高稀”条件下合成聚（对苯二甲本-1,3-丙二醋）（PTT）环状低聚物的可行性。通过柱色谱分离和环状低聚的和线形低聚物；用核磁共振，质谱和元素分析表征了产物的化学结构；用GPC和HPLC研究了不同大小环的分布。发现在本文实验条件下合成的PTT环状低聚物主要由二，三，四，五和七聚体构成，其中环状三聚体含量最多，没有发现环状六聚体的存在。PTT环状低聚物的熔程为92.3-222.6℃，熔融后是无色，透明的低粘度液体，于250℃将PTT环状低聚物分别在辛酸亚锡，1-乙基－3－氯四丁基锡氧烷，钛酸四丁酯和三氧化二锑催化下进行开环聚合反应，制备了特性粘数为0.18-0.49dL/g的聚合物。     

遥爪低聚物合成的进展

简要叙述近年来遥爪低聚物合成的发展，包括自由基聚合，阳离子聚合，基团转移聚合，开环聚合等，利用遥爪低聚物人们可按不同用途对高分子材料提出的性能要求进行聚合物的分子设计。     

稀土催化的开环聚合研究进展

稀土催化剂在开环聚合中表现出极高的催化活性,本文总结了近十年来稀土催化剂在内酯、交酯、环醚、环碳酸酯、环羧酸酐等单体开环聚合中的应用,结合催化剂结构与聚合效果总结了稀土催化剂在聚合过程可控和聚合物结构控制方面的独特优势,并介绍了稀土催化的新型开环聚合方法.     

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。     

Novel Biodegradable Aliphatic Polycarbonate Based on Ketal Protected Dihydroxyacetone

Summary: A novel aliphatic polycarbonate based on ketal protected dihydroxyacetone was synthesized by ring‐opening polymerization of cyclic carbonate monomer, 2,2‐ethylenedioxypropane‐1,3‐diol carbonate (EOPDC), in bulk. Effects of polymerization conditions such as catalysts, catalyst concentration, reaction temperature and reaction time on the polymerization were investigated. The polycarbonate obtained was characterized by GPC, FTIR, ¹H NMR, ¹³C NMR and DSC. The study on in vitro degradation of PEOPDC shows that the degradation mainly results from surface erosion.

Synthesis of an aliphatic polycarbonate with a high molecular weight by ring‐opening polymerization of cyclic carbonate monomer EOPDC.     

Synthesis and characterization of polycyclic structures and linear polycarbonate copolymers from a bisphenol A dimer

An o,o′‐methylene‐bridged bisphenol A (BPA) dimer 2 was synthesized by a one‐step reaction between formalin and excess BPA in the presence of a cation exchange resin in a polar aprotic solvent. Novel oligomeric polycyclic structures were synthesized by the reaction of reactive difunctional halides, methyl phosphonic dichloride, phenyl phosphonic dichloride, and dimethyl dichlorosilane with the BPA dimer under high‐dilution conditions. The yields of the polycyclics were quite high. NMR and matrix‐assisted laser desorption ionization–time of flight mass spectrometry (MALDI–TOF MS) were very useful in the characterization of the dimer and its oligomeric polycyclic analogs. These polycyclics can potentially be used as precursors for advanced thermosetting materials. A series of polycarbonate copolymers of BPA were synthesized by solution polycondensation of the methylene bridged dimer of BPA with triphosgene. Alternatively, the co‐polycarbonate containing crosslinkable moieties was synthesized by in‐situ polymerization of BPA and BPA dimer with triphosgene. The copolymers were characterized by GPC. TG/DTA and DSC were used to investigate the thermal properties of the co‐polycarbonates. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 927–935, 1999     

Soluble tin(II) macroinitiator adducts for the controlled ring‐opening polymerization of lactones and cyclic carbonates

Polyesters and poly(ester carbonates) were synthesized via ring‐opening polymerization with new tin(II) macroinitiator adducts containing oligomeric L ‐lactide (LLA), rac‐lactide (rac‐LA), and ?‐caprolactone (CL). The novel initiating species were synthesized by the reaction of LLA, rac‐LA, or CL with Sn(OEt)₂ (monomer concentration/initiator concentration ≤20) and then were dissolved in methylene chloride or toluene and stored in a stoppered flask for the subsequent ring‐opening polymerization of cyclic esters and carbonates. The soluble tin alkoxide macroinitiators yielded predictable and quantitative initiation of polymerization for up to 1 month of storage time at room temperature. The resulting polymers displayed low polydispersity (≤1.5), and a high monomer conversion (>95%) was obtained within relatively short polymerization times (≤2 h). Adjusting the monomer/macroinitiator ratio effectively controlled the molecular weights of the polymers. NMR was used to characterize the initiating species and polymer microstructure, and size exclusion chromatography was used to determine the molecular weight properties of the polymers. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3434–3442, 2002     

环碳酸酯开环聚合物制备、性能和应用研究进展

综述了近年来环碳酸酯开环均聚与共聚产物的制备、性能与应用研究进展     

Lipase-catalyzed ring-opening polymerization of molecularly pure cyclic oligomers for use in synthesis and chemical recycling of aliphatic polyesters

The lipase-catalyzed ROP of molecularly pure cyclic oligomers with a definite degree of oligomerization is analyzed with respect to the molecular weights of the resulting polymers and certain kinetic parameters of the enzymatic reaction. Cyclic BA dimers, trimers, and tetramers polymerize faster than the equivalent monomer; however, the latter produces PBA of significantly higher molecular weight. The reason is that the ring opening of the cyclic monomer is slow, leading to a lower initiator concentration than that produced by the cyclic BA dimer and trimer. Similarly, the cyclic BS dimer produces PBS of higher molecular weight than that obtained from the cyclic BS trimer.     

Synthesis and characterization of novel aliphatic polycarbonates

A new six‐membered cyclic carbonate monomer, 5‐benzyloxy‐trimethylene carbonate, was synthesized from 2‐benzyloxy‐1,3‐propanediol, and the corresponding polycarbonate, poly(5‐benzyloxy‐trimethylene carbonate) (PBTMC), was further synthesized by ring‐opening polymerization in bulk at 150 °C using aluminum isobutoxide [Al(OⁱBu)₃], aluminum isopropoxide, or stannous octanoate as an initiator. The results showed that a higher molecular weight polycarbonate could be obtained in the case of Al(OⁱBu)_3. The protecting benzyl group was removed subsequently by catalytic hydrogenation to give a polycarbonate containing a pendant hydroxyl group (PHTMC). The polycarbonates obtained were characterized by Fourier transform infrared spectroscopy, ¹H NMR,¹³C NMR, gel permeation chromatography, and DSC. NMR results of PBTMC offered no evidence for decarboxylation occurring during the propagation. The pendant hydroxyl group in PHTMC resulted in an enhancement of the hydrophilicity of the polycarbonate. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 70–75, 2002     

新型螺环单体的合成和自由基聚合反应的研究

新型螺环单体的合成和自由基聚合反应的研究王宏鲁剑涛冯品珍（中国科学技术大学研究生院化学部北京１０００３９）关键词自由基聚合，新单体合成，螺环单体，自由基共聚虽然离子型开环聚合早已为人熟知，但是自由基开环聚合反应的研究和应用开发还刚刚起步．...     

含1,2-亚乙基单元的双酚A聚碳酸酯非光气法合成和表征

以双酚A(BPA),碳酸乙二酯(EC)和碳酸二甲酯(DMC)为原料,制备双酚A二元醇(Ⅰ)和双酚A碳酸酯(Ⅱ),并用红外光谱与核磁共振波谱对其结构进行表征.通过Ⅰ与Ⅱ的共缩聚反应及Ⅱ的自聚实现了主链中含有—CH2CH2—单元的双酚A型聚碳酸酯(PC)的非光气法合成,用凝胶渗透色谱法(GPC)和TGA-DSC对PC的分子量和热性质进行分析.结果表明,Ⅱ在240℃自聚6h后产物的Mn可达17.6×103,主链中—CH2CH2—单元的引入,可以降低聚合物的Tg,提高其结晶性,所得聚合物具有良好的热稳定性.     

Mapping the characteristics of the radical ring‐opening polymerization of a cyclic ketene acetal towards the creation of a functionalized polyester

Radical ring‐opening polymerization of cyclic ketene acetals is a means to achieve novel types of aliphatic polyesters. 2‐methylene‐1,3‐dioxe‐5‐pene is a seven‐membered cyclic ketene acetal containing an unsaturation in the 5‐position in the ring structure. The double bond functionality enables further reactions subsequent to polymerization. The monomer 2‐methylene‐1,3‐dioxe‐5‐pene was synthesized and polymerized in bulk by free radical polymerization at different temperatures, to determine the structure of the products and propose a reaction mechanism. The reaction mechanism is dependent on the reaction temperature. At higher temperatures, ring‐opening takes place to a great extent followed by a new cyclization process to form the stable five‐membered cyclic ester 3‐vinyl‐1,4‐butyrolactone as the main reaction product. Thereby, propagation is suppressed and only small amounts of other oligomeric products are formed. At lower temperatures, the cyclic ester formation is reduced and oligomeric products containing both ring‐opened and ring‐retained repeating units are produced at higher yield. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4587–4601, 2009