对-乙酰氧基苯甲酸与聚对苯二甲酸乙二醇酯共缩聚反应及醚键形成的研究

监测了对-乙酰氧基苯甲酸与聚对苯二甲酸乙二醇酯(PET)共缩聚反应过程中1HNMR图谱及特性粘度的变化,对乙酰氧基酯交换反应及乙酰脂肪酯的反应活性进行了研究。并研究了以低分子量PET或对苯二甲酸二乙二醇酯为原料时反应中醚键的形成及其进入共聚酯链的规律性。     

热致性液晶嵌段共聚酯的合成及表征

以对羟基苯甲酸甲酯和乙二醇为原料，通过熔融酯交换反应合成中间体（Ⅰ）：双（对一羟基苯甲酸）乙二醇酯．用溶液缩合法合成了三种不同嵌段长度的液晶嵌段共聚酯（Ｐ２４７、Ｐ２７７、Ｐ２７４）作为液晶聚合物与热塑性聚合物的“增容剂”．ＦＴＩＲ，Ｈ ＮＭＲ分析表明，嵌段共聚酯的结构和组成与分子设计基本相符；偏光显微镜证实，嵌段共聚酯在一定温度范围内为热致性向列型液晶，在较低温度为均相，在较高温度为两相结构．     

对—乙酰氧基苯甲酸与聚对苯二甲酸乙二醇酯共缩聚反应及醚键…

监测了对－乙酰氧基苯甲酸与聚对苯二甲酸乙二醇酯（ＰＥＴ）共缩聚反应过程中ＨＮＭＲ图谱及特性粘度的变化，对乙酰氧基酯交换反应及乙酰脂肪酯的反应活性进行了研究，并研究了以低分子量ＰＥＴ或对苯二甲酸二乙二醇酯为原料时反应中醚键的形成及其进入共聚酯链的规律性。     

含柔性间隔基液晶聚酯合成的新途径

以对羟基苯甲酸甲酯和含亚甲基数不同的二醇为原料，在酯交换催化剂Ｔｉ（ＯＣ４Ｈ９－ｎ）４／Ｎ（ｎ－Ｃ４Ｈ９）３和热稳定剂亚磷酸三苯酯（Ｃ６Ｈ５Ｏ）３Ｐ存在下，采用熔融酯交换反应合成出单体（Ｉ），Ｉ与对苯二甲酰氯聚合成６种含柔性间隔基液晶聚酯。经ＤＳＣ、偏光显微表征，６种聚合物均为热致性向列型液晶。     

对羟基苯甲酸／对苯二甲酸／双酚A三元共聚酯的核磁共振表征

对羟基苯甲酸／对苯二甲酸／双酚Ａ三元共聚酯的核磁共振表征吴大诚，谢新光，李瑞霞，王勇（成都科技大学纺织工学院成都６１００６５）周子南，高新风，孝延文，张建国（中国科学院长春应用化学研究所高分子物理开放实验室长春１３００２２）关键词对羟基苯甲酸／对苯二...     

全芳族有规交替共聚酯的合成及液晶性

合成了一系列三元和四元全芳族共聚酯，其链结构特征为有规交替地分布着对羟苯甲酰基（HB）单元。结构考察了HB在链中对共聚酯性能的影响，与不含HB的共聚物相比，发现其熔融温度下降，耐热性提高；液晶性不受损害；共聚物熔融时呈Schlieren或thred-like向列型织态结构；径熔融合冷却所得固态聚合物的激光小角光散射图象呈现明暗相同的斑纹。     

新型手性近晶C相液晶共聚酯的设计与合成

以对苯二甲酰氯 ,2 ,5 二 [4 ((s) 2 甲基丁氧基 )苯甲酰氧基 ]对苯二酚和乙二醇、一缩乙二醇、二缩三乙二醇、三缩四乙二醇和聚乙二醇为单体 ,采用低温溶液缩聚方法 ,合成了一系列新的手性近晶C相串型液晶共聚酯 .共聚酯通过GPC、DSC、TG、WAXD、偏光显微镜和旋光仪等方法表征 .发现所有的共聚酯加热至各自的熔点以上都能形成液晶态 ,在液晶态可以观察到近晶相的焦锥织构 ,所有的手性化合物和共聚酯都有较高的旋光性 .通过变温X 射线衍射研究结合偏光显微镜观察和旋光分析证明它们为手性近晶C相 .所有共聚酯的熔融温度 (Tm)和各向同性温度 (Ti)随共聚酯中不同柔性链段长度的增加逐渐降低 ,液晶态温度范围变宽     

热致液晶共聚酯与聚酯热塑弹性体复合物的制备与性能

原位缩聚法制备了一系列(对羟基苯甲酸-对苯二甲酸-间苯二酚)(HB-TA-RES)热致液晶共聚酯与聚对苯二甲酸丁二酯-聚四亚甲基醚热塑弹性体(PBT-PTMG)复合物,并用POM,TGA,WAXD,SEM及动态应力流变仪等手段进行了表征.复合物在较宽的共聚酯含量范围(30 wt%~70 wt%)或共聚酯组成不同时(共聚酯中HB含量20 mol%~80 mol%)均具有热致液晶行为.当复合物中共聚酯含量≤50 wt%以及共聚酯中对羟基苯甲酸(HB)含量≤60 mol%时,共聚酯分子的结构更加均匀化,结晶组分的结晶行为受到限制,基体与液晶组分具有较好的复合效果,不表现明显的相分离行为.复合物与相应的纯共聚酯相比,具有较好的热稳定性;其粘度均比基体PBT-PTMG小.当复合物中共聚酯含量≥30 wt%时,其粘度下降尤为显著,表明其具有较好的加工性.     

嵌有长聚醚软段液晶共聚酯的合成

本文用对苯二甲酰氯、对苯二酚、己二醇及分子量为1000或2000的聚丁二醇醚,经溶液缩聚制备了嵌段聚醚聚酯,其介晶单元含量只为21.2重量％(或37.5mol％)即可在宽的温度范围内呈现明显的液晶性.~1H-NMR谱表明,产物的聚酯段呈嵌段微观序列分布.     

热致液晶三元共聚酯酰亚胺的合成与表征

采用直接熔融缩聚方法由１ ,６ － 己撑－ 双（４ － 羟基酞酰亚胺）（ＢＨＰＩ） 、对羟基苯甲酸（ＰＨ ＢＡ） 和对苯二甲酸（ＴＰＡ） 合成一系列三元共聚酯酰亚胺。对聚合物进行示差扫描量热（ＤＳＣ） 、偏光显微镜（ＰＬＭ） 、广角Ｘ－ 射线衍射（ＷＡＸＤ） 等分析表征,结果表明该系列聚合物具有向列型液晶特征。     

液晶弹性体的研究进展

综述了液晶弹性体的结构、制备以及应用的研究现状, 介绍了液晶弹性体突出的物理性能,并对液晶弹性体的发展前景做了展望。     

Electro-optical properties of ferroelectric liquid crystalline polymers

Ferroelectric liquid crystalline polymers (FLCPs) were synthesized. These ferroelectricities were confirmed directly by measuring polarization reversal currents and other electro-optical properties. The smectic layer structure of FLCP was also studied. A chevron structure similar to that of low molecular weight FLC was observed even in an FLCP cell; but the zigzag defects were not so sharp, which means that it is easy to obtain a good orientation even in large-area displays.     

Segmented polyurethanes with 4,4′-bis-(6-hydroxyhexoxy) biphenyl as chain extender. I. Synthesis and characterization of 2,4-tdi-polyurethanes

Polyurethanes composed of 2,4-toluene diisocyanate (TDI), poly (butylene adipate) diols (PBA) of different molecular weights, and 4,4′-bis-(6-hydroxyhexoxy) biphenyl (BHHBP) were prepared by a two-step solution polymerization process. The polyurethanes were char-acterized by elemental analysis, NMR, and SEC. The thermal properties were investigated by DSC, DMA, and optical polarizing microscopy. Dependent on the molecular weight of the PBA, a shift in the glass transition temperature T_g of the polyurethanes has been observed by DSC and DMA. Polyurethanes based on poly (butylene adipate)s of M_n ～ 2000 exhibited a T_g nearly independent on the hard-segment content up to 50% LC hard segments, indicating the existence of mainly phase separated soft and hard segments. By shortening the PBA chain length up to 1,000 and further to 600, the T_g of the polyester soft-segment phase increases with growing hard-segment content, a consequence of enhanced interaction between the hard and soft segments. This tendency is observed to the greatest extent at polyurethanes with the shortest, polyester diol and can be interpreted as a partial miscibility or compatibility of hard and soft segments. Although in polyurethanes with PBA 2000 the mesophase can be proven at a hard-segment content of ～ 40%, its appearance in polyure-thances prepared with PBA 1000 or PBA 600 requires a hard-segment content > 60%. © 1995 John Wiley & Sons, Inc.     

Effect of the length of the substituents on the phase structure and transition behavior of a series of laterally attached side‐chain liquid‐crystalline polynorbornenes

A series of polynorbornenes (PNBEs) with 1,4‐bis[(3′‐fluoro‐4′‐n‐alkoxyphenyl)ethynyl]benzene mesogens (n = 1–12, where n is the number of methylene units in the substituents of the mesogens) laterally attached to polymer backbones through a one‐carbon spacer were previously synthesized by the ring‐opening metathesis polymerization of the corresponding norbornene‐based monomers. Differential scanning calorimetric results showed that the first‐order transition temperatures exhibit an odd–even alternation, especially when PNBEs have lower values of n. PNBE (n = 8), similar to the previously studied PNBEs (n = 9–12), shows a smectic C (S_C) phase at room temperature (Kim, Pugh, and Cheng, Macromolecules, 33, 8983, 2000.) According to one‐ and two‐dimensional wide‐angle X‐ray scattering experiments, PNBEs (n = 2–7) exhibit a nematic (N) phase with S_C fluctuations, whereas for PNBE (n = 1), only an N phase is observed. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 3029–3037, 2001     

含偶氮基团的聚甲基丙烯酸酯型侧链液晶高分子的合成与表征

报道了一种新的含对甲氧基苯氨羰基偶氮苯基团的甲基丙烯酸酯单体及其自由基聚合产物的合成。利用元素分析,＾１Ｈ－ＮＭＲ、ＵＶ－Ｖｉｓ、ＧＰＣ、ＴＧ－ＤＴＡ、ＰＯＭ及Ｘ－射线衍射等手段对其结构与性能进行了表征。结果表明,偶氮单体不具有液晶性质,而聚合物则具有向列型液晶相存在,并且它在空气中具有很好的热稳定性。     

Synthesis and characterisation of polymethacrylates containing para-, meta- and ortho-monosubstituted azobenzene moieties in the side chain

Three sets of novel side-chain liquid crystalline polymers with monosubstituted azobenzene moieties in the side-chain have been studied. These are poly(p-(4′-methoxy-4-oxyhexyloxy azobenzene) benzyl methacrylate) (PPHABM), poly(m-(4′-methoxy-4-oxyhexyloxy azobenzene) benzyl methacrylate) (PMHABM) and poly(o-(4′-methoxy-4-oxyhexyloxy azobenzene) benzyl methacrylate) (POHABM). The chemical structure of the monomers was confirmed by ¹H NMR, ¹³C NMR spectroscopy and elemental analysis. The structural characterisation of the polymers was performed by ¹H NMR spectroscopy and gel permeation chromatography, and their phase behaviour and liquid crystalline properties were studied using differential scanning calorimetry, polarised optical microscopy and wide-angle X-ray diffraction. The results show that the transitional behaviour of side-chain liquid crystalline polymers containing monosubstituted azobenzene moieties depends strongly on the position of the substituent on the azobenzene moiety; for example, the ortho-monosubstituted polymers do not form liquid crystalline phases, but all the para- and meta-monosubstituted polymers exhibit a smectic A phase. Furthermore, the glass transition temperature (T_g ) of the polymers decreases in the order, para > meta > ortho. For the PPHABM and PMHABM polymers the isotropic temperature (T_i ) and liquid crystalline range (ΔT, from T_g to T_i ) are found to be in the order, para > meta, although it is surprising that the associated enthalpy changes in these polymers is the opposite order, meta > para.     

Polymers containing substituted 2-phenyl-benzoxazole side-chain groups: Synthesis and phase behavior

The synthesis of substituted 2-phenyl-benzoxazoles has been accomplished by ring closure of Schiff bases. The compounds have been used as precursors of acrylic derivatives displaying LC properties: Four comb-like homopolymers have been obtained by radical catalysis from the acrylic monomers. The polymers have been characterized by ¹H-NMR, DSC, x-ray diffraction, viscometry, and polarizing microscopy. Three of the polymers exhibit liquid crystalline properties of smectic type. © 1996 John Wiley & Sons, Inc.     

Calorimetric study of blends of poly(butylene terephthalate) and liquid crystalline copolyester

A calorimetric study of blends of poly(ethylene terephthalate-co-p-oxybenzoate), PET/PHB, with poly(butylene terephthalate), PBT has been carried out in the form of as-spun and drawn fibres. DSC melting and crystallization results show that PBT is compatible with LCP and the crystallization of PBT decreases by the addition of LCP in the matrix. The crystallization behaviour of blend fibres is investigated as a function of temperature of crystallization. A detailed analysis of the crystallization course has been made utilizing the Avrami expression. The isothermal calorimetric measurements provide evidence of decrease of rate of crystallization of PBT on addition of the liquid crystalline component up to about 50% by weight. The values of the Avrami exponents change in the temperature range from 200° to 215°C. Dimensionality changes in crystallization could be due to LCP mesophase-transition.     

Nanosized Shape‐Changing Colloids from Liquid Crystalline Elastomers

A method to prepare shape‐changing nanospheres from liquid crystalline elastomers is reported. The nanosized colloids are prepared by a miniemulsion process. During this process, colloids are prepared from a liquid crystalline (LC) main‐chain polyester and subsequently crosslinked into a nanometer‐sized LC elastomer. The ability of these LC elastomers to change their shape at the phase transition temperature from the smectic A to the isotropic phase was detected by temperature‐dependent transmission electron microscopy. The phase transition‐induced shape change leads to strongly shape anisotropic nanosized elastomer particles.

     

液晶聚合物网络研究进展

综述了液晶聚合物网络的新进展。包括液晶热固体、液晶弹性体和液晶互穿网络。介绍了各种网络的合成、主要性能和应用前景。