相同软硬段质量配比聚醚酯弹性体PEG/PBT的结构与表征

以熔融缩聚法合成了一系列聚乙二醇(PEG)/聚对苯二甲酸丁二醇酯(PBT)聚醚酯热塑性弹性体,用NMR,FTIR,DSC及力学性能测试等方法表征了材料的结构及性能.讨论了在相同软硬段质量配比下,不同软硬段长度对材料性能的影响.结果表明,随着软段PEG长度增加,硬段PBT长度相应增长,弹性模量基本保持不变,抗拉强度、屈服应力及特性粘度增加.     

聚乙二醇/聚对苯二甲酸丁二醇酯聚醚酯弹性体的合成与表征——不同硬段长度对材料性能的影响

以熔融缩聚法合成了一系列基于聚乙二醇 (PEG) 聚对苯二甲酸丁二醇酯 (PBT)的聚醚酯热塑性弹性体 ,用NMR、IR、DSC及力学性能测试等方法表征了材料的结构及性能 .讨论了在相同软段长度情况下 ,不同硬段长度对材料结构与性能的影响 .实验表明 ,随着体系中硬段PBT长度的减小 ,弹性模量、抗拉强度降低 ,特性粘度、吸水量及断裂形变量增加 ,材料性能良好可调     

PBT/PEG型聚醚酯的鉴定

采用红外光谱、核磁共振和DSC热分析手段对一种未知聚合物样品进行表征。通过对样品红外谱图的吸收峰位和强度及对其核磁共振氢谱中各质子化学位移归属的分析,判明该样品为PBT/PEG型聚醚酯弹性体,且不含游离的聚乙二醇组分。样品的DSC测试表明其与PBT/PEG型聚醚酯的热行为较相符。该分析为此类聚合物提供了一种简单、快速且结果可靠的鉴定方法。     

聚对苯二甲酸丁二醇酯－co-聚丁二酸丁二醇酯-b-聚乙二醇嵌段共聚物的合成及表征

用熔融缩聚法合成了一系列基于聚对苯二甲酸丁二醇酯（PBT）、聚丁二酸丁 二醇酯（PBS）及聚乙二醇（PEG）的嵌段共聚物（PBT－co-PBS/PEG)。^1H NMR结 构分析显示,软段摩尔百分含量恒为20％。随组成中PBS含量增加,软段质量百分 含量略微升高,硬段PBT平均序列长度由2.80逐步减至1.23,PBS平均序列长度由1. 27逐步增加到4．76,无规度在1．1附近,两者呈无规分布。受组成及硬段平均序 列长度变化影响,材料内部呈微观相分离状态,DSC热分析曲线上可分别观察到软 、硬段熔点（Tm,s,Tm,h)及玻璃化转变温度（Tg,s,Tg,h)。硬段熔点及结晶度随 PBS含量升高而降低,在50－60mol％处达到最小值,则是PBS与PBT二者间形成共晶 所致。力学性能测试及水解降解实验表明,将脂肪族聚酯PBS引入PEGT／PBT共聚体 系,可赋予高分子链更好的柔韧性及亲水性,加快降解速率。     

聚酯的生物改性

从四个方面综述了近年来聚对苯二甲酸乙二酯(PET)和聚对苯二甲酸丁二酯(PBT)生物改性的研究进展:(1)在聚酯合成中采用生物原料;(2)采用共聚技术制备可生物降解性共聚酯;(3)生物活性物质在聚酯中的引入改性,可提高其生物相容性和抗菌能力,在聚酯用于人造器官时,可使血管纤维原细胞的细胞增殖;(4)生物酶对聚酯进行水解改性,可减轻重量,并改善吸湿性、染色性等性能。     

溶液喷丝法制备组织工程无纺布支架

在高压氮气作用下用溶液喷丝制备了组织工程支架.聚乙二醇/聚对苯二甲酸丁二醇酯(PEGT/PBT)共聚物的氯仿溶液经高压氮气流喷丝,继而沉积成无纺布.为了提高支架的生物相容性,将透明质酸水溶液喷涂到PEGT/PBT丝表面.结果表明,所制备的支架材料的生物相容性良好,细胞外基质透明酸能显著提高无纺布支架的生物相容性.     

碳纳米管对聚酯相容共混体系酯交换反应的影响

采用熔融共混制备了聚对苯二甲酸丙二酯(PTT)/聚对苯二甲酸丁二酯(PBT)共混体系以及碳纳米管(C NTs)填充改性的三元复合体系,通过核磁共振波谱仪(NMR)研究了CNTs对共混基体组分间酯交换反应的影响,并结合透射电子显微镜( TEM)、沉降实验等多种测试结果初步探讨了影响的机理.研究结果表明,PTT/PBT为典...     

聚乳酸-聚乙二醇-聚乳酸三嵌段共聚物的降解性能

以辛酸亚锡为引发剂,聚乙二醇大分子为共引发剂进行现交酯开环聚合,制备了系列聚乳酸（PLA）－聚乙二醇（PEG）－聚乳酸（PLA）三嵌段共聚物。从共聚物在生理盐水 中降解时特性粘度[η],质量和热行为的变化,考察了PEG分子量和丙交酯／PEG（摩尔比）对共聚物降解行为的影响,结果表明,PEG嵌段对共聚物的降解速率有重要影响,丙交酯／PEG一定时,PEG分子量越大,共聚物越容易降解,PEG嵌段长度一定时,丙交酯／PEG越大,共聚物降解速率越小。     

生物可降解共聚物聚丁二酸/对苯二甲酸丁二醇酯(PBST)的序列结构及结晶性研究

制备了高分子量的聚丁二酸丁二醇酯,并通过与对苯二甲酸二甲酯的无规共聚调节其生物可降解性及力学性能,得到了具有优良机械性能和不同生物降解速度的一系列共聚物,并对共聚物序列结构、热力学性能、结晶性进行了研究.结果表明,该共聚物为无规共聚物,PBS和PBT分别结晶.共聚物的结晶熔点符合无规共聚物的Flory方程.     

聚三亚甲基碳酸酯的改性研究

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巨大的潜在应用。本文结合近几年的研究进展,综述了聚三亚甲基碳酸酯改性的三大类方法,详细介绍了聚三亚甲基碳酸酯的功能化方法与途径、讨论了聚三亚甲基碳酸酯与不同类别单体共聚改性的研究现状及性能变化,并总结了共混改性对聚三亚甲基碳酸酯性能的影响,最后介绍了改性后的聚三亚甲基碳酸酯在生物医用领域的应用。     

三元乙丙橡胶环氧化增韧聚对苯二甲酸丁二酯的研究

三元乙丙橡胶环氧化增韧聚对苯二甲酸丁二酯的研究王学会，张会轩，王新华，王志刚，蒋俊光，姜炳政（吉林工学院化工系，长春，１３００１２）（中国科学院长春应用化学研究所）关键词三元乙丙橡胶，环氧化，ＰＢＴ，增韧作用，共混物聚对苯二甲酸丁二酯（ＰＢＴ）具有优...     

Poly(butylene terephthalate)–polyarylate blends

In this paper we focus on miscible blends of two engineering polymers: poly(butylene terephthalate) (PBT) and a polyarylate (PAr). The issue of transesterification in these blends will be addressed, followed by a discussion of the crystallization kinetics of PBT, poly(ethylene terephthalate) and several PBT/PAr blends. The ability to estimate polymer–polymer interaction parameters in blends from melting point depression will also be discussed. The amorphous phase behavior of the PBT/PAr blends has been explored primarily using dielectric spectroscopy. For blends in which PBT has crystallized, we observe two relaxations associated with T_g-like motion, and this behavior is interpreted in light of our recent work on order–disorder interphases in crystalline blends.     

Preparation of Long Glass Fiber Reinforced Poly(butylene terephthalate) Composites with Chemical Bonding Interphase

Long glass fiber reinforced poly(butylene terephthalate) composites (LGF/PBT) were prepared by a new process. PBT oligomers with low melt viscosity were impregnated into the reinforcing glass fiber and then grafted to the reinforcing glass fiber surface treated with a silane coupling agent during solid‐state polymerization. The reinforcing glass fiber, after removing ungrafted PBT from LGF/PBT, was investigated with the result showing the presence of a grafted PBT layer on the surface of treated glass fiber. The mechanical properties of the composites were significantly improved owing to the grafting of the PBT macromolecules. The fiber length distribution and fiber arrangement in the injection molded composites were also studied and the results showed that a small amount long glass fiber could be connected at junction points in the composites, which were of benefit to the mechanical properties of the composites.     

Synthesis and Characterization of Block Copolymers of Poly(Butylenes Terephthalate-Co-Adipate)

The block copolyesters of poly(butylene terephthalate)(PBT) and poly(butylene adipate)(PBA) were prepared by a novel two-stage method. In the first stage, high molecular weight PBT and PBA were melt mixed in the presence of 1,4-butanediol at 275 °C. In the second stage, vacuum was applied to raise the molecular weight. The extent of transesterification was controlled by the proportion of 1,4-butanediol. The sequence distribution and the thermal properties of the block copolyesters were characterized by NMR and DSC respectively.     

Poly(Urethane)-Crosslinked Poly(HEMA) Hydrogels

Abstract

Hydrogels have been prepared from 2-hydroxyethyl methacrylate polymerized in the presence of isocyanate-terminated poly(ethylene glycol) (PEG) crosslinking agents. PEGS of molecular weights 200, 400, and 1000 were investigated. The crosslinked nature of the hydrogels was demonstrated by their insolubility in solvents which normally dissolve poly(HEMA). Hexamethylene diisocyanate (HDI) was mainly used as the isocyanate. The molecular weight of the PEG and the crosslinker content significantly influenced the equilibrium water sorption and mechanical properties of the saturated networks. It was observed that as the molecular weight of the PEG increased, the water sorption increased and the nominal modulus decreased. However, for higher levels of cross-linker, water sorption decreased and modulus increased at low molecular weight PEG; for PEG 1000, water absorption increased as crosslinker content increased. These results are explained by the competing effects of flexibility, crosslink density, and hydrophobicity contributed by the various constituents of the hydrogels.     

聚乙烯/聚乙二醇共混物中极性组分的表面富集

采用衰减全反射傅立叶变换红外光谱(FTIR-ATR)和扫描电子显微镜研究了极性组分聚乙二醇在聚乙烯／聚乙二醇共混物中的表面富集特性。研究结果认为不同组分表面自由能的差异以及聚乙烯基体的结晶异相排斥作用是导致聚乙二醇组分向共混物表面富集的主要驱动力，而极性组分相区的大小和分布则是影响其选择性迁移过程的重要因素。因此，可以通过添加合适相容剂的办法对聚乙二醇组分的表面富集程度进行有效的调控。     

聚对苯二甲酸乙二醇酯和聚对苯二甲酸丁二醇酯化学扩链反应

综述了用于聚对苯二甲酸乙二醇酯（ＰＥＴ）、聚对苯二甲酸丁二醇酯（ＰＢＴ）化学扩链反应的羧基加成型和羟基加成型扩链剂，以及缩合型扩链反应、羧基加成型扩链反应和羟基加成型扩链反应、羧羟基同时加成型扩链反应。讨论了扩链反应、反应特性和扩链产物的性能，并简要介绍了国内研究概况。参考文献２０篇。     

Poly(butylene terephthalate)/clay nanocomposite compatibilized with poly(ethylene‐co‐glycidyl methacrylate). II. Nonisothermal crystallization

Melting behaviors and nonisothermal crystallization of poly(butylene terephthalate)/poly(ethylene‐co‐glycidyl methacrylate) (PBT/PEGMA), PBT/commercial modified montmorillonite clays (PBT/Clay), and PBT/exfoliated silicates (PBT/PEGMA/Clay) nanocomposites were studied by wide‐angle X‐ray diffraction and differential scanning calorimeter. PEGMA is used as a compatibilizer. For both isothermally and nonisothermally crystallized samples, PEGMA facilitates the recrystallization of PBT during the heating scans, and leads to a less degree of perfection of the crystals. However, the clay hinders the recrystallization growth during heating scans, and increases perfection of the crystals. Nonisothermal crystallization kinetics was described by kinetic models and undercooling was taken into account. The PEGMA would lead to an increase of the blend viscosity, rendering the chains less mobile and lower the crystallizability of PBT in PBT/PEGMA. The well‐dispersed exfoliated silicates in PBT/PEGMA/Clay cause a large number of nuclei to precede crystallization. The fold surface free energy (σ_e) and activation energy also supported the interpretation. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 564–576, 2008     

Miscibility and properties of poly(l-lactic acid)/poly(butylene terephthalate) blends

Binary blends of poly(l-lactide) (PLLA) and poly(butylene terephthalate) (PBT) containing PLLA as major component were prepared by melt mixing. The two polymers are immiscible, but display compatibility, probably due to the establishment of interactions between the functional groups of the two polyesters upon melt mixing. Electron microscopy analysis revealed that in the blends containing up to 20% of poly(butylene terephthalate), PBT particles are finely dispersed within the PLLA matrix, with a good adhesion between the phases. The PLLA/PBT 60/40 blend presents a co-continuous multi-level morphology, where PLLA domains, containing dispersed PBT units, are embedded in a PBT matrix. The varied morphology affects the mechanical properties of the material, as the 60/40 blend displays a largely enhanced resistance to elongation, compared to the blends with lower PBT content.