聚对氧化偶氮苯酚酯系列热致性液晶高分子的合成及液晶态研究

本文用界面缩聚法合成聚对氧化偶氧苯酚酯系列热致性液晶高分子。并用DSC,X-光衍射和偏光显微镜对其结构和液晶相进行了表征与研究。观察液晶态织态结构,计算液晶态时分子链间距,并观察聚合物取向液晶态的结晶结构。     

聚十三烷二酸对偶氮氧苯酚酯的合成及液晶态性质

本文用十三烷二酸和对偶氮氧苯酚合成了具有长链柔性单元的聚十三烷二酸对偶氮氧苯酚酯。用各种方法对其液晶态性质进行了表征和研究,并与结构相似的液晶聚合物聚十二烷二酸对偶氮氧苯酚酯及聚十三烷二酸2,2′-二甲基对偶氮氧苯酚酯进行了比较,用实验数据阐明了产生相转变奇偶效应的主要原因。并由热分析数据从又一方面证实了Flory关于液晶态中各向异性相与各向同性相共存的观点。     

壳聚糖/二氯乙酸溶致液晶的热致相转变

关于壳聚糖及其各种衍生物的溶致液晶的研究已有报道^[13],但尚未见到有关壳聚糖/有机酸液晶溶液的热致相转变的报道.本文研究了壳聚糖/二氯乙酸液晶溶液的相转变,并探讨了该体系的相转变机理.     

三元无规芳—脂族聚酯酰胺的热致液晶行为

采用低湿溶液缩聚的方法合成了对苯二甲酰氯，二甲基联苯胺和己二醇为单体的芳酯族液晶聚酯酰胺。用ＤＳＣ，Ｘ光衍射分析和偏光显微镜等手段研究了该系列聚酯酰胺的热致液晶行为，确认了二甲基联苯胺单体用量在２０％（ｍｏｌ）的情况下，所得聚酯酰胺仍为向列型液晶聚合物。由于聚酯酰胺分子间聚酰胺链段之间的氢键作用，随着二甲基联苯胺用量增加至６０ｍｏｌ％时，所得的聚酯酰胺己无液晶转变温度，其液晶区间即从熔融温度直至分     

热致液晶聚酯酰亚胺的非等温相转变动力学研究

以差示扫描量热法对热致液晶聚酯酰亚胺的结晶过程和液晶化过程的非等温相转变动力学行为进行了初步研究，根据Ｊｅｚｉｏｒｎｙ方法处理数据得到了表征聚合物非等温相转变动力参数Ｚｃ，Ｇｃ并对其进行了讨论，结果表明，在所研究的条件下聚合物的相转变过程基本上符事Ｊｅｚｉｏｒｎｙ结论，但两种相转变的成核与生长方式是不同的。     

甲壳素类液晶高分子的研究Ⅷ. N-邻苯二甲酰化壳聚糖/DMSO液晶溶液的热致相转变

合成了氮上完全取代的邻苯二甲酰化壳聚糖 (PhthCS) .用DSC研究了PhthCS DMSO液晶溶液的热致相转变 .偏光显微镜和DSC测定都表明临界浓度为 43wt% .在浓度高于 43wt%的溶液的DSC曲线中观察到了除了液晶 各向同性液体转变 (清亮点 )外还有一个明显的凝胶 溶胶转变 .凝胶 溶胶转变温度和转变焓均比文献报道的不规则取代的N 邻苯二甲酰化 O 乙酰化壳聚糖大得多 ,可见取代的规整性对凝胶 溶较转变有很大的影响 .根据DSC研究结果绘制了PhthCS DMSO体系的相图     

热致液晶性序列嵌段共聚酯的多重热转变

本文利用DSC研究了热致液晶性序列嵌段共聚酯在不同升温速率时的多重熔融转变,和不同冷却速率对结晶与熔融过程的影响。发现T_(kn)和T_(ni)与热历史、升温速率及成形条件均无关,T_(kn)=425.86K,T_(nt)=480.60K;而T_(in)与T_(nk)随冷却速率增大而降低。     

一种不含介晶基团的两亲性高分子的热致液晶行为

一种不含介晶基团的两亲性高分子的热致液晶行为张希，张瑞丰，沈家骢，赵晓光，周恩乐（吉林大学化学系，长春，１３００２３）（中国科学院长春应用化学研究所，中国科学院长春高分子物理开放实验室）关键词两亲性高分子，疏水作用，热致液晶热致液晶分子结构中含有几何...     

热致液晶性聚酯酰胺的研究进展

热致液晶性聚酯酰胺由于其独特的化学结构，形成了一新的液晶聚合物体系，本文就类热致性晶聚合物体系的研究进展作进行了述评。     

条带织构装饰技术观察含T─型液晶基元的热致性聚芳酯液晶态的向错

采用条带织构装饰新技术研究了含Ｔ─型液晶基元的热致性聚芳酯液晶态的向错形态．经过培养的液晶样品无需剪切，淬火后便可呈现出围绕向错点取向排列的条带织构，而条带织构长轴的垂直方向正代表了液晶基元的指向矢方向，这样，在普通偏光显微镜下就能直接观察到这些条带织构装饰的强度Ｓ＝±１／２和Ｓ＝±１的向错，并观察到Ｓ＝－３／２的高强度向错和闭环状的反转壁．     

含柔性间隔链段的芳香共聚酯热致性液晶高分子的结构研究

本文用富里叶红外光谱方法研究了一系列柔性间隔链段长度不等的芳香共聚酯热致性液晶高分子。测定了它们的变温光谱和偏振性质。并将谱带的变温行为与液晶转变相关联。结果表明,芳香共聚酯热致性液晶中液晶基元之间的相互作用很强而柔性间隔链之间的相互作用很弱。柔性间隔链段主要是伸直的反式构象。从一些谱带的二向色性估算了体系的有序度参数以及取向角。分子链的取向程度随柔性间隔链段长度的增加而减小。     

STUDY ON THE PHASE TRANSITION KINETICS OF THERMOTROPIC LIQUID CRYSTALLINE AROMATIC-ALIPHATIC COPOLYESTER

The phase transition kinetics of thennotropic liquid crystalline aromatic-aliphatic regular copolyester: were studied by DSC. By means of Kissinger's method the kinetic equation and parameters including activation energy, rate order and preexponential factor for phase transition from nematic to isotropic were obtained. The activation energy from crystal to nematic was also presented.     

含两种不同介晶基团的半刚性共聚酯液晶态的结构研究

用Ｘ－光衍射，偏光显微镜及ＤＳＣ对含两种不同长度介晶基团４，４’－联苯二酚（Ⅰ）和对苯二甲酸二（对羟苯基）酯（Ⅱ）的系列共聚酯的液晶态进行了表征，据其液晶态中两种介晶单元的堆砌方式提出了可能的模型，这种模型很好地解释了液晶态的Ｘ－光衍射分布．     

热致液晶共聚酯／Nylon－1010共混物的研究

利用偏光显微镜（ＰＬＭ），差示扫描量热计及广角Ｘ－射线衍射等手段研究了热致液晶共聚酯／Ｎｙｌｏｎ－１０１０共混体系．发现当热致液晶共聚酯（ＨＴＨ１０）含量达到３０％时共混物微结构与纯ＨＴＨ１０相似．尼龙－１０１０的结晶度先是随ＨＴＨ１０含量增加而增加，随后又随之下降，但其结晶温度却随ＨＴＨ１０加入而单调下降，共混物的熔融热焓△Ｈｍ在ＨＴＨ１０含量为３０％时与计算值有较大的偏差，广角Ｘ－射线衍射结果表明，此时共混物结构发生了较为明显的变化，两组份之间在此时存在一定的相互作用．     

CRYSTALLIZATION BEHAVIOR OF A THERMOTROPIC LIQUID CRYSTAL COPOLYESTER

A thermotropic liquid crystal copolyester resin based on p-hydroxybenzoic acid, 2, 6-naphthoic acid, hydroxyquinone and PET was synthesized by melt condensation and studied. The results based on DSC and X-ray diffraction indicated that there were a rapid and a slow crystallization processes for the copolyester at certain conditions. A critical temperature was suggested, below which the slow crystallization could hardly happen. Above the critical temperature the extent of the slow crystallization process depended not only on annealing temperature but also on the annealing time. A fine crystal structure with high melting point and narrow diffraction peak was formed under favorable conditions.     

PHASE STRUCTURES AND TRANSITION BEHAVIORS OF A TRIPHENYLENE DISCOTIC LIQUID CRYSTAL

The phase behaviors and structures of a triphenylene-derived discotic liquid crystal (LC) hexa-n-octoxyl-triphenylene (C8HET) were studied using the combined techniques of differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD), selected area electron diffraction (SAED) and polarized light microscopy (PLM). Onedimensional (1D) powder WAXD results at different temperatures coupled with DSC and PLM observations revealed that the C8HET compound possessed an LC phase and three different crystalline (K3, K2 and K1) phases below the isotropic (Ⅰ)melt. The I (←→) LC phase transition was thermodynamically reversible and independent of the heating and cooling rates. The development and experimental observation of the three crystalline phases relied on different thermal histories. Among the three crystalline phases in C8HET, the K3 phase is the most stable phase, while the K2 and K1 phases are metastable. Note that the K1 phase only formed via a quenching process. On the basis of structure sensitive diffraction experiments such as 2D WAXD of oriented samples and SAED of single crystals, detailed structures and molecular packings of these four ordered phases were identified. The LC phase exhibited a hexagonal columnar phase with 2D lattice dimensions of a = b = 2.38 nm and γ= 120°. All the three crystalline phases possess monoclinic unit cells, yet the γ angle is not 90° in the cases of the K2 and the K3 phases, while in the case of the K1 phase the α angle is not 90°.     

热致性液晶共聚酯的拉伸流动行为

采用入口收缩流动的实验方法研究了改性PET/ 80PHB液晶共聚酯LCP80的拉伸流动行为 ,考察了拉伸速率、温度等对其拉伸粘度、Trouton比的影响 .实验结果表明 ,LCP80的入口压降值很大 ,其中由拉伸引起的入口压降是主要的 .在该文实验条件下LCP80均表现出拉伸稀化现象 ,并且Trouton比值都远大于 3 .根据流动中液晶织态结构的变化解释了实验现象 ,并对入口收缩流动的实验数据处理方法作了改进 ,比Beery的方法更为合理 ,也具有更广的适用性 .     

全芳香族共聚酯的结构和其液晶行为研究

本文对不同组成的对苯二甲酸(TPA),对羟基苯甲酸(PHBA),联苯二酚(BP),间苯二甲酸(IPA)共聚酯采用热台偏光显微镜、电子显微镜、X-射线衍射、激光小角散射、差热等技术进行了研究.实验结果表明,在一定的组成范围内共聚酯熔体有很好的液晶性.重点讨论了分子组成、转变行为、液晶性的关系,并对液晶相的形态结构进行了表征.     

PRIMARY STUDY ON BLENDS BASED ON THERMOTROPIC LIQUID CRYSTAL COPOLYESTER AND PET

The blend system composed of PET and thermotropic liquid crystal copolyester based on hydroxy benzoic acid, terephthalic acid, diacetylnaphthalene and PET was studied. The results indicated that LCP could play the role of crystal nuclei. The introduction of LCP decreased the melt viscosity of the system and fibrillous structure could be formed in favor conditions.