结晶态双酚A型聚碳酸酯固相缩聚的研究

在自制的反应器中将结晶态、无定形两种双酚A型聚碳酸酯(BAPC)预聚体固相缩聚合成了高摩尔质量的双酚A型聚碳酸酯.采用DSC、IR对双酚A型聚碳酸酯(BAPC)的熔融行为和结构进行了表征.结果表明,BAPC在固相缩聚后,玻璃化转变温度升高,热稳定性增强,其中BAPC为结晶态时固相缩聚的温度低于无定形态BAPC的固相缩聚温度,且结晶态BAPC固相缩聚后为无定形态.     

连续光气化、缩聚合成聚碳酸酯的研究

本文讨论了连续光气化、缩聚合成聚碳酸酯的小实验和模型实验结果;着重研究了光化和缩聚反应器结构,搅拌效果和返混问题;并对一段加碱二步法工艺作了较多的工作。在连续运行时,分子量波动范围可控制在±3000之内,残留双酚A在1000ppm以下,质量达到目前间歇法水平。本文提出的装置经进一步改进后,可望在低温连续光气化缩聚工业生产聚碳酸酯中应用。     

聚碳酸酯合成技术进展

综述了聚碳酸酯的国内外合成技术进展情况。介绍了目前工业生产中采用的界面光气法、溶液光气法、普通熔融酯交换法及非光气熔融法生产工艺 ,讨论了苯酚氧化羰基化法与双酚A氧化羰基化法合成聚碳酸酯的最新研究动态。对我国聚碳酸酯工业的发展提出了建议     

基于3-(羟基甲基磷酰基)-2-甲基-丙酸含磷聚碳酸酯的固相缩聚

聚碳酸酯(PC)作为增长速度最快的通用工程塑料,其阻燃性难以满足日益增长的应用需求。通过熔融聚合将磷元素引入PC聚合物链中难以得到较高分子量的含磷PC。因此采用固相缩聚法,以碳酸二苯酯(DPC)、双酚A(BPA)、3-(羟基甲基磷酰基)-2-甲基-丙酸为原料合成得到了含磷PC,分别通过NMR、GPC、DSC和TG对所得含磷聚碳酸酯的结构、分子量和分子量分布、玻璃化温度、热稳定性等进行了测试和表征。结果表明:通过固相缩聚可以明显提高含磷PC的分子量、玻璃化温度和初始分解温度;经固相缩聚后,含磷PC的数均分子量由2950 g/mol提高到10 900 g/mol;玻璃化转变温度由86℃提高到133℃;初始分解温度由238.8℃提高到361.3℃。     

非光气熔融酯交换合成聚碳酸酯的研究进展

非光气熔融酯交换缩聚法相对于传统光气界面缩聚法合成聚碳酸酯有着成本较低、无污染、不使用溶剂等优势并且作为新一代绿色环保型工艺已经受到了世界各国的关注。本文着重从非光气熔融酯交换缩聚法合成聚碳酸酯的反应动力学机理、催化剂和非光气法的工艺条件上进行了阐述,为今后从事开发非光气熔融酯交换缩聚法的工作者指明出一定的道路。     

光气法生产聚碳酸酯的工艺流程

综述了光气法生产聚碳酸酯的工艺流程，主要包括溶液缩聚法和界面缩聚法；详细介绍了光气界面缩聚法制备聚碳酸酯的原料配制、聚合反应过程及后处理过程；最后概括了光气化法界面缩合成聚碳酸酯反应过程的影响因素，主要有原料物质的量比、有机相惰性溶剂的选择及回收、反应过程的pH值、胶液萃取精制工艺的操作及分子量控制剂的选择等。     

酯交换法合成聚碳酸酯催化剂性能考察

以双酚A和碳酸二苯酯为原料,采用非光气熔融酯交换法合成聚碳酸酯。考察了氢氧化钾、氢氧化钠、四丁基氢氧化铵、碳酸钠、吡啶以及复合催化剂对聚碳酸酯合成反应速率及聚碳酸酯分子量和色差的影响。研究表明,氢氧化钾作为催化剂较适合于聚碳酸酯合成工艺,使用复合催化剂可以得到分子量较高、色差较低的聚碳酸酯。     

酯交换缩聚法合成聚碳酸酯的研究进展

聚碳酸酯的酯交换缩聚工艺具有绿色环保的特性,符合当今世界可持续发展的主题,相对于传统的光气法工艺更具有发展前途。综述了国内外在酯交换缩聚工艺的机理以及催化剂选择和工艺条件上取得的进展。指出碳酸二苯酯与双酚A酯交换反应是四面体机理,正反应是二级反应,逆反应是三级反应;以La(ACAC)_3作催化剂,得到的产品不但粘均分子量较高,而且热稳定性非常好;利用酯交换熔融聚合工艺可以解决传统光气法的环境问题,而固相聚合可以得到超高分子量的产品。     

非光气聚碳酸酯技术的发展：参考文献和附录（英文）

介绍了十年来制备聚碳酸酯工艺的发展情况。近年来，GE、Bayer和Asahi／Chi Mei等公司已开始利用非光气技术(也称为熔融工艺)进行工业化生产聚碳酸酯。简要介绍了传统的界面聚合工艺和非光气技术制备聚碳酸酯的情况。介绍了碳酸二苯酯与双酚A聚合制备聚碳酸酯的酯交换或熔融聚合方法，并概述了3种制备碳酸二苯酯的生产工艺(包括直接和非直接生产技术)，     

聚碳酸酯合成技术进展

综述了聚碳酸酯(PC)已经实现工业化的4种合成聚合工艺,按照各生产工艺的流程和特点对其进行了阐述。同时,介绍了非光气法缩聚阶段的关键设备。非光气法PC生产工艺已经在竞争中逐步占据优势,未来需要进一步优化酯交换反应和缩聚反应阶段的反应器设计。     

Solid‐state polymerization of bisphenol A polycarbonate with a spray‐crystallizing method

A novel crystallization method for the production of high‐molecular‐weight bisphenol A polycarbonate by solid‐state polymerization is suggested. In this method, a low‐molecular‐weight polycarbonate prepolymer is dissolved in a solvent and then partially crystallized with a novel spray‐crystallizing method to prepare crystallized polycarbonate particles having a very uniform and porous structure with a narrow melting region. As a result, during solid‐state polymerization, the phenol byproduct can be easily removed from the polymerizing porous polycarbonate particles, and the polymerization rate is dramatically increased. In particular, the effects of the crystallization methods on secondary crystallization during solid‐state polymerization and the melting behavior have been investigated with differential scanning calorimetry studies. The final product, a high‐molecular‐weight polycarbonate, displays a very narrow molecular weight distribution and uniform physical properties. A simultaneous process and an adequate reactor design for spray crystallization and solid‐state polymerization are also suggested. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

聚乳酸合成的研究进展

简要介绍了生物降解高分子材料聚乳酸的基本性能,对近年来以乳酸为原料合成聚乳酸的两类方法进行了总结,并对聚乳酸合成的发展前景进行了展望。     

基于熔融/固相缩聚制备中高分子量聚乙醇酸

聚乙醇酸（PGA）通常可通过乙交酯开环聚合和乙醇酸熔融缩聚制得,但乙交酯开环聚合工艺复杂,导致PGA成本高。相较而言,乙醇酸熔融缩聚制备PGA工艺简单,成本较低,但难以获得中高分子量的PGA。因此,本文基于熔融/固相缩聚路线,系统研究了催化剂种类与含量、酯化温度、固相缩聚温度等聚合工艺条件对PGA外观形态、特性黏度和热稳定性的影响。发现三氟甲烷磺酸铋对乙醇酸熔融缩聚具有较好的催化效果,优化熔融/固相缩聚条件如下：催化剂含量为0.20%（质量）,酯化温度为180℃,熔融缩聚和固相缩聚温度为210℃,固相缩聚时间为12 h。在该熔融缩聚条件下,PGA的最高特性黏度为0.36 dl/g,进一步固相缩聚处理可以将PGA的特性黏度提高到0.59 dl/g。     

Two-Component initiator systems for the ring-opening polymerization of oligomeric cyclic bisphenol-A carbonates. Studies with in situ generated wittig salts

A two-component initiator system based on the in situ generation of Wittig salts (alkytriarylphosphonium bromides) has been developed for the ring-opening polymerization of cyclic bisphenol-A (BPA) carbonate oligomers for potential use in composite applications so that the prepolymer can suitably wet the composite material before being converted to high molecular weight polymer. The Wittig salt precursors (an alkyl bromide, such as hexadecyl bromide, and a triarylphosphine, such as triphenylphosphine) did not independently initiate significant ring-opening polymerization of the oligomeric cyclic BPA carbonate mixture. However, when the two mixtures of cyclic BPA carbonate oligomers and initiator component were combined, a high molecular weight polymer (M_w = ∼ 65,000) was produced. The polymerization initiating species is thought to be hexadecyltriphenyl-phosphonium bromide. Consistent with this hypothesis is the observation that authentic Wittig salts did initiate ring-opening polymerization to provide high molecular weight polycarbonate. The effects of structure and concentration of the initiator components, reaction temperature, time, etc. on polymerization were studied; in general, the degree of polymerization ranged from 65 to 85%. © 1996 John Wiley & Sons, Inc.     

Solid state polymerization of bisphenol A polycarbonate: Effect of the crystallization method and polymerization conditions

A study on the effect of the crystallization method on the solid state polymerization (SSP) process of bisphenol A polycarbonate has been performed. Prepolymer samples were crystallized via four different techniques (solvent induced, shear induced, organic salt induced, and thermal crystallization) and SSP progress was checked by measuring the molecular weight increase. The fastest polymerization rate was obtained with prepolymers crystallized with acetone. The reaction rates were correlated with the crystallinity and plasticization of solvents, which both affected the chain mobility. The experiments conducted using different sweep gas flow rates and different particle sizes showed that, for the acetone‐crystallized prepolymers, the reaction rate was limited by the by‐product diffusion inside the polymer particles and from the surface of the particles into the sweep gas. ¹H‐nuclear magnetic resonance analysis proved that polymers prepared through a solid state process had a consistently lower content of Fries rearrangement by‐products with respect to commercial samples obtained by standard melt polycondensation methods. POLYM. ENG. SCI., 55:1024–1029, 2015. © 2014 Society of Plastics Engineers     

聚乳酸直接合成的研究

综述了近年来国内外研究聚乳酸直接合成的进展情况,概述了乳酸直接合成的几种方法,研究了熔融聚合、溶液聚合中影响聚乳酸相对分子质量的因素,探讨了固相聚合机理。     

Melt polymerization of bisphenol‐A and diphenyl carbonate in a semibatch reactor

The effect of thermodynamic phase equilibrium on the kinetics of semibatch melt polycondensation of bisphenol‐A and diphenyl carbonate was studied for the synthesis of polycarbonate. In the melt‐polymerization process, a partial loss of diphenyl carbonate occurs as the reaction by‐product phenol is removed from the reactor. To obtain a high molecular weight polymer under high temperature and low‐pressure conditions, a stoichiometric mol ratio of the two reactive end groups needs to be maintained during the polymerization. In this work, vapor–liquid equilibrium data for a binary mixture of phenol and diphenyl carbonate are reported and they are used in conjunction with the Wilson equation to calculate the exact amounts of diphenyl carbonate and phenol returned from a reflux column to the reactor. A good agreement between the reactor model simulations and the experimental polymerization data was obtained. It was also observed that diphenyl carbonate is quickly consumed during the early stage of polymerization and the fraction of evaporated diphenyl carbonate refluxed to the reactor is essentially constant during this period. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1253–1266, 2001     

聚乳酸合成和改性

介绍了聚乳酸的合成工艺一步法、两步法及其改进,通过分析聚乳酸自身存在的特性及局限性,介绍了近几年聚乳酸的改性发展,包括耐热性的改性,亲水性改性以及机械性能方面的改性。     

树核星形聚合物合成的研究进展

简介了合成树核星形聚合物常用的树状分子,综述了近年来原子转移自由基聚合(ATRP)、可逆加成-断裂链转移聚合(RAFT)、开环聚合(ROP)、阴离子聚合和光引发自由基聚合在合成树核星形聚合物中的应用。