填料对聚合物共混物相分离行为的影响

近年来,由于粒子填充聚合物共混物的广泛运用,复合材料的结构研究具有重要意义.除了研究粒子在聚合物中的分散外,关于粒子对聚合物共混物的相分离影响也做了大量工作.研究结果表明粒子的尺寸,粒子的表面处理以及粒子含量对聚合物共混物相分离热力学以及动力学有重要影响.由于粒子对聚合物组分的选择吸附、聚合物分子对粒子的润湿作用、填料对聚合物相区生长的阻碍导致了聚合物共混物-填料体系相行为的复杂性.本文扼要地综述了聚合物共混物-填料体系相分离的理论基础以及实验结果,介绍了粒子对相分离的影响因素,并展望了该领域的研究趋势和前景.     

聚合物共混：Ⅰ.聚合物共混物的制备方法

本讲主要介绍聚合物共混物的制备方法,其中包括熔融共混、溶液共混、胶乳共混、冷冻干燥共混、接技共聚共混、互穿聚合物网络、就地反应型共混、分子共混等.     

受限条件下不相容聚合物共混物的形态演变研究进展

不相容聚合物共混物形成的相结构决定着共混材料的各项性能。近几年,研究发现不相容聚合物共混物受限条件下的相结构与非受限条件下的相结构有很大不同。本文从理论模型、实验结果以及影响因素(包括受限程度、组分比、剪切速率和粘弹性)等方面,综述了近年来开展的受限条件对不相容聚合物共混物相结构影响的研究进展,指出了现有研究的一些不足之处并展望了该领域的发展趋势。     

分子量分布对聚合物体系相行为影响的研究进展

聚合物合成工艺往往会使聚合物原料的分子链链长呈现出长短不一的状态,这就使得该聚合物的分子量分布呈现出多分散性。而这种多分散性的分子量分布会对不同性质的聚合物共混体系的相行为产生不同的影响。本文阐述了研究分子量分布对多相多组分聚合物体系的相行为影响的重要性,并分别从高分子溶液体系、嵌段共聚物、聚合物一聚合物共混体系、胶体...     

显微镜图像分析研究聚丙烯/尼龙1010共混物相结构及其性能

用扫描电子显微镜图像分析研究了聚丙烯/聚酰胺1010共混物及其部分相容体系的相形态结构,计算了表征相结构和尺寸的结构参数,如分散相的平均直径、平均弦长和分散相的质心相关距等.并分别讨论了聚丙烯/聚酰胺1010共混物及其部分相容体系的相形态以及其结构参数与共混物组成的关系.测定了聚合物及其共混物体系的力学性能,讨论了共混物组成与力学性能的关系.聚丙烯/聚酰胺1010共混物的拉伸模量与组成的关系较为复杂,但其部分相容体系的拉伸模量与组成呈线性关系.聚丙烯/聚酰胺1010及其共混物体系的屈服强度与共混物组成均呈线性关系.表征相结构的两相平均弦长比(l-1/-l2)与组成以及共混物体系力学性能与组成的关系,二者相似.同时讨论了体系力学性能随相尺寸等的变化规律.     

粘度比对刚性链高分子与柔性链高分子共混物微结构的影响

粘度比对刚性链高分子与柔性链高分子共混物微结构的影响何嘉松,卜文胜,张洪志,许向青（中国科学院化学研究所,北京,１０００８０）（化工部北京化工研究院,北京,１０００１３）关键词高分子共混物,热致液晶聚合物,聚合物加工影响柔性链高分子与柔性链高分子共混...     

几种典型固体聚合物体系的^13C自旋—晶格弛豫特性

用固体高分辨ＮＭＲ系统地研究了几种典型的均聚物，共聚物，聚合物共混物以及用接枝共聚物增容的不相容聚合物共混体系的＾１３Ｃ自旋－晶格弛豫特性。研究结果表明：＾１３Ｃ自旋－晶格弛豫时间是表征固体聚合物体系的很有用参数，它能提供有关本体聚合物微观形态结构的信息，并要望建立聚合物的微观怀宏观性能的关系，它不仅能准确无误地反映共混体系中可能存在的各种相互作用，而且能定性地给出相互作用的大小和准确地指明相互     

离聚物对含液晶聚合物聚砜体系的增容作用

离聚物对含液晶聚合物聚砜体系的增容作用刘杰，何嘉松（中国科学院化学研究所工程塑料国家重点实验室北京１０００８０）关键词增容作用，离子聚合物，热致液晶聚合物，高分子共混物，原位复合材料工程塑料与液晶聚合物（Ｌｒｙ）共混（形成所谓的原位复合材料）时在降低...     

聚合物体系拉伸流变行为的表征及研究进展

聚合物的拉伸流动在吹膜、纺丝、热成型等加工中扮演着支配的角色,因此掌握聚合物熔体在拉伸条件下的流动行为对于控制和预测其加工性能具有重要意义。相对于剪切流动,拉伸粘度对于大分子的结构、填充粒子的各向异性、共混物中两相的结构等更加敏感。本文简要介绍了当前用于拉伸流变研究的常用装置及其原理,并举例描述了单一组分聚合物、聚合物纳米复合材料和聚合物共混物等体系拉伸流变研究的现状和成果,最后指出了当前拉伸流变研究领域存在的一些不足之处并进行了展望。     

多组分聚合物体系热力学理论研究进展

概述了多组分聚合物体系热力学理论研究中，从经典的Ｆｌｒｏｙ－Ｈｕｇｇｉｎｓ平均场理论到Ｐｒｉｇｏｇｉｎｅ－Ｆｌｏｒｙ现代状态方程理论（ＥＯＳ）的发展历程，着重讨论了用Ｆｌｏｒｙ的ＥＯＳ及其简化理论研究各种类型聚合物共混体系相容性的发展状况。     

Miscibility and crystallization kinetics in blends of poly(ethylene terephtalate) and thermotropic liquid crystal polyesters

Binary blends of poly(ethylene terephtalate) (PET) and thermotropic liquid crystal polyester (TLCP) have been prepared by both solution and melt blending methods. The TLCPs utilized were Vectra (Hoechst Celanese), TR-4, a TLCP synthesized in our laboratory, and a block copolymer consisting of three TR-4 units followed by three PET units. The phase behavior of the blends was studied by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA) and optical microscopy. The results show that none of the blends is miscible, but significant interactions exist between the PET phase and the TLCP phase in the case of TR-4 and TR-4 block copolymer blends. These interactions lead to a different nucleation mechanism in these blends compared to that in PET/Vectra.     

COMPUTER SIMULATION OF MISCIBILITY AND SELF-ASSEMBLY STRUCTURE FOR POLYMER-CONTAINING SYSTEMS WITH SPECIAL INTERACTIONS

The miscibility and structure of A-B copolymer/C homopolymer blends with special interactions were studied by aMonte Carlo simulation in two dimensions. The interaction between segment A and segment C was repulsive, whereas it wasattractive between segment B and segment C. In order to study the effect of copolymer chain structure on the morphologyand structure of A-B copolymer/C homopolymer blends, the alternating, random and block A-B copolymers were introducedinto the blends, respectively. The simulation results indicated that the miscibility of A-B block copolymer/C homopolymerblends depended on the chain structure of the A-B copolymer. Compared with alternating or random copolymer, the blockcopolymer, especially the diblock copolymer, could lead to a poor miscibility of A-B copolymer/C homopolymer blends.Moreover, for diblock A-B copolymer/C homopolymer blends, obvious self-organized core-shell smicture was observed inthe segment B composition region from 20% to 60%. However if diblock copolymer composition in the blends is less than40%, obvious self-organized core-shell structure could be formed in the B-segment component region from 10 to 90%.Furthermore, computer statistical analysis for the simulation results showed that the core sizes tended to increasecontinuously and their distribution became wider with decreasing B-segment component.     

Toward microphase separation in epoxy systems containing PEO–PPO–PEO block copolymers by controlling cure conditions and molar ratios between blocks

Nanostructuring of thermosetting systems using the concept of templating and taking advantage of the self-assembling capability of block copolymers is an exciting way for designing new materials for nanotechnological applications. In this first part of the work, reactive blends based on stoichiometric amounts of a diglycidylether of bisphenol-A epoxy resin and 4,4′-diaminodiphenylmethane cure agent modified with three poly(ethylene oxide)-co-poly(propylene oxide)-co-poly(ethylene oxide) block copolymers were studied. Cure advancement of these systems was analyzed by differential scanning calorimetry. The experimental results show a delay of cure rate, which increases as copolymer content and PEO molar ratio in the block copolymer rise. Infrared spectroscopy shows that PEO block is mainly responsible of physical interactions between the hydroxyl groups of growing epoxy thermoset and ether bonds of block copolymer. These interactions are mainly responsible for the delaying of cure kinetics. The molar ratio between blocks also has a critical influence on the delaying of the cure rate. A mechanistic approach of cure kinetics allows us to relate the delay of cure as a consequence of block copolymer adding to physical interactions between components.     

Block copolyetheramides III. Blends of nylon-6 and block copolyetheramides

Blends of Nylon-6 and block copolyetheramides with hard segments of Nylon-6 and soft segments of poly(tetramethylene ether) were prepared. The impact strength of the blends was enhanced by the presence of the block copolyetheramides as compared to the Nylon-6. Different block copolyetheramides exhibited different effects on the impact strength which could be described as the difference in compatibility between the Nylon-6 and the Nylon-6 segments of the block copolymers. The difference in compatibility was verified by the investigations of TEM and DSC. As the caprolactam content of the block copolyetheramides increased, the compatibility between the Nylon-6 and the Nylon-6 segments of the block copolymers was enhanced and the blends exhibited a higher impact strength in general. The heat deflection temperature of the blends decreased as the polyether content (depending on the type and the content of the block copolyetheramide) of the blends increased. When the polyether content was ≤ or 20 wt %, a small decrease in heat distortion temperature was found. © 1994 John Wiley & Sons, Inc.     

Specific Interactions in a Variety of Multicomponent Polymers

For a variety of multicomponent polymers including simple blends, block copolymers, IPNs, lonomer blends, homopolymer/block copolymer blends and composites composed of Inorganic particles and polymer matrix, the current situation and trend of introducing specific Interactions and its effect on the misclbility and properties of the systems have been reviewed with emphasis on the recent results obtained in the author' s laboratory.     

Hydrogen bonding interactions,crystallization, and surface hydrophobicity in nanostructured epoxy/block copolymer blends

Hydrogen bonding interactions, phase behavior, crystallization, and surface hydrophobicity in nanostructured blend of bisphenol A‐type epoxy resin (ER), for example, diglycidyl ether of bisphenol A (DGEBA) and poly(ε‐caprolactone)‐block‐poly(dimethyl siloxane)‐block‐poly(ε‐caprolactone) (PCL–PDMS–PCL) triblock copolymer were investigated by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry, transmission electron microscopy, small‐angle X‐ray scattering, and contact angle measurements. The PCL–PDMS–PCL triblock copolymer consisted of two epoxy‐miscible PCL blocks and an epoxy‐immiscible PDMS block. The cured ER/PCL–PDMS–PCL blends showed composition‐dependent nanostructures from spherical and worm‐like microdomains to lamellar morphology. FTIR study revealed the existence of hydrogen bonding interactions between the PCL blocks and the cured epoxy, which was responsible for their miscibility. The overall crystallization rate of the PCL blocks in the blend decreased remarkably with increasing ER content, whereas the melting point was slightly depressed in the blends. The surface hydrophobicity of the cured ER increased upon addition of the block copolymer, whereas the surface free energy (γ_s) values decreased with increasing block copolymer concentration. The hydrophilicity of the epoxy could be reduced through blending with the PCL–PDMS–PCL block copolymer that contained a hydrophobic PDMS block. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 790–800, 2010     

聚丙烯-聚乙烯嵌段共聚物和相应共混物的热分析

用DSC研究了预期为聚丙烯-聚乙烯两嵌段共聚物(PP-PE)和相应共混物(PP+PE)在热学性能上的差异。经用不同分子量的PP和PE及其共混物进行试验后发现,由于PP和PE在结晶时出现过冷的难易不同。在共混物降温热分析曲线上,当降温速率较快时仅出现一个放热峰,而降温速率较慢时出现PP和PE各自的结晶放热峰,从而解释了文献中的不同结果。并发现共混物的PP和PE熔融、结晶温度均较组分相同的嵌段共聚物的相应温度为高;嵌段共聚物中PP和PE的△H_f值均低于均聚物的△H_f值,而PE的值降低尤甚。我们认为这与嵌段间的共价键限制嵌段活动和结晶过程有关,从而确认DSC热分析可以作为识别是否为嵌段共聚物的一种方法. 本工作的结果表明,所研究的PP-PE试样具有嵌段结构。     

Dissipative particle dynamics study on the interfaces in incompatible A/B homopolymer blends and with their block copolymers

Dissipative particle dynamics, a simulation technique appropriate at mesoscopic scales, has been applied to investigate the interfaces in immiscible binary A/B homopolymer blends and in the ternary systems with their block copolymers. For the binary blends, the interfacial tension increases and the interface thickness decreases with increasing Flory-Huggins interaction parameter chi while the homopolymer chain length is fixed. However, when the chi parameter and one of the homopolymer chain length is fixed, increasing another homopolymer chain length will induce only a small increase on interfacial tension and slight decrease on interface thickness. For the ternary blends, adding the A-b-B block copolymer will reduce the interfacial tension. When the mole number of the block copolymer is fixed, longer block chains have higher efficiency on reducing the interfacial tension than the shorter ones. But for the block copolymers with fixed volume fraction, shorter chains will be more efficient than the longer ones on reducing the interfacial tension. Increasing the block copolymer concentration reduces interfacial tension. This effect is more prominent for shorter block copolymer chains.     

IONIC THERMOPLASTIC ELASTOMERS: A REVIEW

The incorporation of small amount of ionic groups into hydrocarbon polymers results in unique physical properties and these polymers are called ionomers. They are effectively cross-linked through the association of ionic groups, forming multiplets or clusters. These associations are thermally labile to a greater or lesser extent depending on the composition of the ionic domains. In elastomeric ionomers, the thermolabile nature of the ionic domains permits the adequate flow at the processing temperatures, and hence the term ionic thermoplastic elastomers. Polar plasticizers are incorporated into ion-containing polymers in order to reduce the melt viscosity, resulting from the strong ionic associations, and to improve the processability. The introduction of ionic groups into the block copolymers improves their thermal stability and high temperature performance. The presence of ion-ion interactions in different rubber/plastic blends enhances the mechanical compatibility of the otherwise incompatible blends and thereby results in the formation of ionic thermoplastic elastomers, depending on the rubber to plastic ratios. In the absence of ionic groups the blend components are incompatible, as indicated by poor physical properties of the blends. However, the introduction of ionic groups onto the polymer chains causes a dramatic increase in compatibility between the rubbery and the plastic phases, as indicated by the synergism in physical properties. The present paper reviews the ionic thermoplastic elastomers based on elastomeric ionomers, block copolymer ionomers, and ionomeric polyblends.     

CRYSTALLIZATION OF BLENDS OF AN ASYMMETRIC POLY（OXYETHYLENE）-b-POLY（OXYBUTYLENE） BLOCK COPOLYMER WITH POLY（OXYBUTYLENE）

An oxyethylene/oxybutylene block copolymer with asymmetric volume fraction (E115B103) was blended with oxybutylene homopolymer (Bh) at different volume fractions of the block (φE). Crystallization behavior of the blends was studied and was compared with that of the blends from a symmetric block copolymer (E114B56). It was found that the crystallization temperature of E115B103/B28 blend is lower than that of the blends from symmetric block copolymer. For the blend with φE= 0.30 breakout crystallization with an Avrami exponent n ≈ 3.0 is observed. At φE = 0.22 the blend exhibits a variable crystallization behavior: confined crystallization with n ≈ 1.0 at lower crystallization temperatures but breakout crystallization at high crystallization temperatures. For the blend with φE = 0.14 and sphere morphology confined crystallization occurs at all crystallization temperatures studied. When compared with the blends from symmetric block copolymer, confined crystallization occurs more easily in the E115B103/B28 blends. The SAXS results agree with the isothermal crystallization kinetics. Deformation of the confined crystalline block is observed in the blend with φE = 0.14 and mixed lamellar and cylinder morphologies in the blend with φE = 0.22.