熔融/固相缩聚法合成聚乙醇酸及其性能表征

采用熔融/固相缩聚法合成了聚乙醇酸(PGA)可降解高分子材料,其基本反应步骤为:以乙醇酸为原料,先在190℃熔融状态下将乙醇酸脱水制成分子量为2万左右的低聚物,然后将制得的低聚物在190℃下进行固相缩聚以进一步提高分子量,所制备的PGA产物通过IR、DSC、XRD等手段进行表征。重点考察了不同催化剂,催化剂用量、是否熔融、反应温度、反应时间等因素对固相缩聚的影响,并得出熔融/固相缩聚法合成高分子量的聚乙醇酸的较佳工艺条件:反应温度190℃,二水合醋酸锌与等摩尔量的对甲苯磺酸作为催化剂(质量分数为0.4%),熔融缩聚2h后制得低聚物,然后在190℃下进行固相缩聚,40h后熔融一次,产品粉碎后继续固相缩聚60小时,PGA的重均分子量可达74000左右。     

熔融缩聚/固相缩聚合成聚草酸乙二醇酯及其性能表征

为解决直接聚合聚草酸乙二醇酯粘度低,利用熔融缩聚和固相缩聚联用的工艺合成较高粘度的聚酯。聚草酸乙二醇酯在170℃,氯化亚锡催化剂直接熔融缩聚,125±2℃进行固相缩聚40h,特性粘度增加到0.236dl·g~(-1)。通过红外和核磁进行表征分子结构;利用DSC表征固相缩聚比直接聚合结晶温度高10℃,达到137℃。固相缩聚后聚酯粘度增加,结晶性能改变,结晶温度增加。     

L-聚乳酸固相缩聚的工艺研究

以L-乳酸单体为原料,采用复合催化剂通过直接熔融法合成低聚左旋聚乳酸(PLLA),然后分段控温进行固相缩聚(SSP).对固相缩聚的工艺条件进行了详细的研究.采用粘度法和凝胶渗透色谱法(GPC)对固相缩聚产物PLLA的特性粘数([η])和分子量进行了表征.用差示扫描量热(DSC)研究了固相缩聚产物的熔融行为和结晶度.结果...     

开环聚合-固相缩聚法制备立体嵌段聚乳酸

首先,采用乳酸为引发剂,辛酸亚锡为催化剂,引发丙交酯开环聚合制得具有缩聚活性的L-聚乳酸和D-聚乳酸;然后,将两者熔融共混后进行固相缩聚,合成了一系列立体嵌段聚乳酸。采用核磁共振(NMR)、凝胶渗透色谱(GPC)及差示扫描量热仪(DSC)分析了产物的链结构、重均分子量、热性能,并探讨了均相晶体和立体复合晶体共存情况下的固相缩聚机理。结果表明,固相缩聚产物分子量增长的适宜反应条件为:反应时间30h,较低的催化剂含量,L-聚乳酸质量分数为80%。L-聚乳酸和D-聚乳酸共混物较低的初始立体复合晶体结晶度有利于后续固相缩聚过程中产物分子量的增长;固相缩聚不仅发生在异链之间,而且也发生在同链之间。     

缩聚合成聚芳酯和聚酯－聚醚弹性体的微相复合物

通过原位直接缩聚反应，制备了刚性棒状聚对羟基苯甲酸酯和聚对苯二甲酸丁二醇酯－聚四亚甲基醚多嵌段共聚物和微相复合物，复合物可溶于氯仿等溶剂，可以浇铸成膜，本文研究了ＰＨＢ含量和聚合过程中，基体聚合物溶液浓度对微相复合物形态以及力学性能影响，同共混法相比，原位缩聚法可得到分散更均匀，力学性能更优良的微相复合物。     

固相缩聚PET等温结晶动力学

高聚物等温结晶动力学方面的研究者甚多,由熔融缩聚制备的不同分子量PET的等温结晶动力学及几种不同缩聚催化体系固相缩聚PET的等温结晶动力学已有报道.本文采用一个修正的Avrami方程对固相缩聚PET样品进行系统的等温结晶动力学研究.     

聚苯乙烯负载交联β—环糊精的合成与表征

β－环糊精有氢氧化的钠或氢化钠存在下和相转移催化剂作用下固载到氯甲基化矛苯乙烯树脂上，制成聚苯乙烯固载环糊精树脂，溶液中过量的β－环糊精钠盐与环氧氯丙烷共聚接枝到固载的环糊精树脂上，制备出一类新型的接枝聚合物。以正交实验设计法研究了不同反应体系载休骨交联度或含氯量、反应时间、温度、催化剂种类及抗料比等对固载化反应的影响，讨论了影响接枝反应的条件，对反应结果进行了红外光谱、扫描电镜分析，考察了该树脂     

PET-HBT嵌段热致性液晶共聚酯的合成

液晶高分子材料具有相当高的强度和模量，被誉为当代超级工程塑料．以对羟基苯甲酸甲酯、1，4-丁二醇为主要原料，经熔融酯交换合成双-对羟基苯甲酸丁二醇酯(BBHB)；以四氯乙烷为溶剂，采用溶液缩聚法将过量的BBHB与对苯二甲酰氯(TPC)合成端基为BBHB的齐聚物(PHBT)；以对苯二甲酸二甲酯与乙二醇为原料，经熔融酯交换合成对苯二甲酸双β-羟乙酯(BHET)，然后采用溶液缩聚法将BHET与少量的TPC合成端基为TPC的齐聚物(PTET)；最后以PHBT与PTET为原料，以四氯乙烷为溶剂，采用溶液缩聚法合成目标共聚酯(PET-HBT)。研究了共聚酯的双折射现象及热行为；用偏光显微镜观察了试共聚酯的织态结构并用FTIR表征了共聚酯的微观结构．     

稀土催化体系催化PET固相缩聚的研究

研究了稀土催化体系对聚对苯二甲酸乙二酯固相缩聚反应的催化效果及对所得高分子量聚酯切片性能的影响,发现稀土催化体系可明显提高聚酯固相缩聚的反应速率,稀土催化体系对聚酯固相缩聚反应的催化活性明显高于传统催化体系,其中单一稀土催化体系与混合稀土催化体系在较低温度下具有相近的催化活性,而在较高温度下单一稀土催化体系的催化活性较高;加入稳定剂,不影响稀土催化的固相缩聚反应速率,稀土催化固相缩聚得到的PET样品具有较高的结晶度和较大的晶粒尺寸,其中单一稀土催化所得样品的晶粒尺寸最大,相应地,单一稀土催化的固相缩聚反应活化能也最大;稀土催化体系催化聚酯固相缩聚反应时添加适当稳定剂,可获得与采用传统催化体系得到的PET切片相近的热稳定性。     

固相缩聚法制备高粘度尼龙1111

采用固相缩聚工艺提高尼龙1111的相对粘度,是制备高粘度尼龙1111的有效方法之一。固相后缩聚法制备相对粘度高于2.5的高粘度尼龙1111,宜选择初始相对粘度为2.0的尼龙1111,反应时间12h,反应温度175℃。增粘后的尼龙1111具有更为优良的物理机械性能。     

Preparation of polyamides derived from 1,6-diamantane dicarboxylic chloride by solution polycondensation and interfacial polycondensation

1,6-Diamantane dicarboxvlic acyl chloride ( I ) was used as a monomer with various aromatic diamines to synthesize polyamides by interfacial polycondensation and solution polycon-densation. The polyamides prepared by interfacial polycondensation had inherent viscosities between 0.38 and 0.15 dL/g. The polyamides prepared by solution polycondensation had inherent viscosities between 0.62 and 0.25 dL/g. The polyamides IIIa prepared by solution polycondensation showed the main melting transition at 380°C by dynamic mechanical analysis. In addition, it was quite temperature-stable and maintained good mechanical properties (G′?10⁸ Pa) up to high temperatures close to the main transition well above 350°C. The polyamide IIIA had a tensile strength of 35 MPa, elongations to break of 10%, and initial modulus of 0.8 GPa. Some of the polyamides were soluble in NMP, DMAc, and DMSO, depending on soft segment moiety of diamine ( II ). The polyamides prepared by interfacial polycondensation have a greater tendency to form crystal than those prepared by solution polycondensation, as evidenced by x-ray diffraction studies. These polyamides had glass transition temperatures in the 270–300°C range, and 5% weight loss temperatures up to 435°C in nitrogen. © 1995 John Wiley & Sons, Inc.     

Study of the interfacial polycondensation of isocyanate in the preparation of benzalkonium chloride loaded microcapsules

The preparation of benzalkonium chloride loaded microcapsules was performed by interfacial polycondensation of isocyanates. The present study was made in order to clarify parameters affecting microcapsule wall formation during the course of polymerization. The results presented here show that many interrelated parameters are involved during the microcapsule formation. Each individual component introduced in the preparation was shown to have an effect either on the morphology of the microcapsules or on the mechanical resistance. Benzalkonium chloride seemed to interact mainly in the interfacial polymer precipitation step through a salt effect, or influence the polycondensation reaction rate acting as a catalyst. A contribution of the hydroxylic functions of the surfactant in the polycondensation reaction of the isocyanate was also highlighted. Finally, the organic phase composition was found to be able to modulate the reactivity of hydroxylic functions of the surfactant, leading to very slow reactions in pure xylene. These effects were related to the characteristics of the microcapsules obtained according to different compositions of the formulation system.     

Preparation of colored latex with polyurea shell by miniemulsion polymerization

Colored latexes with polyurea shell were prepared by applying interfacial polycondensation reaction to the miniemulsion polymerization process. These colored latexes were composed of polystyrene core and polyurea shell, and their particle size was adjusted to <100 nm. Diisocyanate was used as a hydrophobic monomer, and the equivalent mole of diamine was used as a hydrophilic monomer for interfacial polymerization. It was important to control the rate of interfacial polycondensation reaction in order to prepare small particles. Dye preservation property of colored latex loaded with oil-soluble dye was investigated. Polyurea shell formed at the surface of latex particles could restrain the migration of dyes from the latex particles and improve the dye preservation property. The ability to prevent dye migration depended on the composition of the polyurea shell.     

非晶聚对苯二甲酸乙二酯的制备与表征

采用引入U-polymer的路线制备了非晶聚对苯二甲酸乙二酯(APET).用DSC和DMA等手段研究了APET的性能.结果表明,经改性后得到的APET无结晶,透明性得到改善,玻璃化转变温度和储能模量都较PET有一定程度提高.     

界面缩聚法合成双酚A芳香环状聚醚砜

聚芳醚（酮、砜）是一类耐高温、耐溶剂的高性能的聚合材料,具有很好的机械和加工性能,广泛应用于工程塑料及复合材料等领域．线性聚芳醚（酮,砜）一般由亲核取代反应或亲电取代反应在极性溶剂中制得,Ｙｏｓｈｉｏ等［１］报道利用相转移催化法制备聚芳醚砜,近年来,...     

聚对苯二甲酸乙二醇酯切片的固相聚合规律

简要介绍了制备高分子量聚对苯二甲酸乙二醇酯的三种方法,重点介绍了其固相聚合的基本原理及主要副反应规律,固相聚合的各种影响因素,如预聚体原料路线、端羟基和羟基平衡、切片形状和尺寸、催化剂、反应副产物等。最后介绍了聚对苯二甲酸乙二醇酯固相滞反应动力学,如温度、时间对固相聚合反应速度的影响,低温固相聚合反应动力学等。     

Synthesis of reactive copolyesters derived from isophthaloyl chloride,bisphenol a,and aliphatic diols with additional reactive groups

Copolycondensation of isophthaloyl chloride, bisphenol A, and aliphatic diols with additional reactive groups were performed in the presence of triethylamine by a trimethyl phosphate/cyclohexane organic/organic interfacial method. The composition of idol and bisphenol A residues in the resulting copolyesters is very close to that in the feed from the initial stage of reaction. The resulting copolyesters with reactive groups can be used for the preparation of various functional polymers. The mechanism of an organic/organic interfacial polycondensation was also discussed. © 1995 John Wiley & Sons, Inc.     

Interfacial polycondensation—Modeling of kinetics and film properties

Interfacial polycondensation (IP) is an important technique used in the encapsulation of a variety of active ingredients and synthesis of thin film composite membranes. The present work seeks to advance our understanding of the mechanisms underlying the reaction, phase separation and film formation in this process, and hence, of how the film properties are influenced by preparation conditions. The model presented here incorporates all the essential physicochemical processes at a fundamental level through simple phenomenologies: ionic equilibria in the aqueous phase, resistances due to external mass transfer, diffusion through polymer film, interfacial reaction, thermodynamics of phase separation, and formation of a coherent film. The model has been tested against the data previously communicated [S.J. Wagh, Studies in interfacial polycondensation. Ph.D. Thesis. IIT Bombay, 2004; S.J. Wagh, S.S. Dhumal, A.K. Suresh, An experimental study of polyurea membrane formation by interfacial polycondensation, Journal of Membrane Science, submitted for publication] on polyurea microcapsules. The influence of the model parameters and preparation conditions, on the properties of the polymer and film and their development during reaction, have been studied. The study provides important insights into the process and should help in designing synthesis methodologies to suit the application.     

链状Salen型高分子席夫碱金属配合物的合成及表征

以对苯二甲酰氯为交联剂,利用界面聚合法合成了链状Salen型高分子席夫碱金属配合物PLSBM(M:CoⅡ,MnⅡ,ZnⅡ,CuⅡ),通过元素分析、红外光谱(FT-IR)、扫描电镜(SEM)、电感耦合等离子原子发射光谱(ICP-AES)和X射线光电子能谱(XPS)对结构进行了表征,发现PLSBM呈不规则的链状结构,配位金属离子与配体形成了稳定的配合物后金属离子的结合能增加了0.5～2.1eV。