液晶高分子的开发研究及进展

液晶高分子量一类较新的高分子材料,具有许多独特的优良性能。本文对液晶高分子的性能,进展及各方面的作了综述报道。     

液晶高分子新型材料：Ⅱ 液晶高分子的合成

1 液晶基元、连接基团和液晶单元合成的任务在于先用适当的聚合方法将小分子的液晶基元通过刚性连接基团连接成较大分子量的液晶单元,将这些液晶单元再通过刚性连接基团连接成刚性液晶大分子链或通过亚甲基连接基团连接成重复单元并进而聚合成为半刚性液晶性大分子链,最后由这些大分子链构成聚合物本体并赋予其液晶性。     

医药中间体5—氨基—2，4，6—三碘异本酸的制备

以间苯二甲酸为原料,经硝化,还原与碘化,合成非离子含碘造影剂的中间体5-氨基-2,4,6-三碘异酞酸。（1）硝化反应,n(硫酸）：n(硝酸钠）:n(间苯二甲酸）=7.9:2.2:1.0,温度70℃下反应3h,产率为86.7%。（2）还原反应,n(铁粉）：n(硝基物）=3.0:1.0。回流反应3h,产率为78.1%;(3)碘化反应,n(氯化碘）：n(氨基物）=3.3:1.0,90℃下反应3h,碘化反应产率为76.2%,每步均经改进,总收率为51.6%,所得产品熔点、UV、IR、^1HNMR、^13CNMR等数据与文献报道一致。     

聚硅氧烷类液晶高分子的研究进展

综述了聚硅氧烷类液晶高分子的最新研究进展,对聚硅氧烷类液晶高分子的各种制备方法和性能进行了总结和评价,对其在液相色谱、光学工程、人工肌肉等方面的应用也作了介绍。     

尼龙6/液晶高分子/玻纤原位复合材料聚集态结构及其力学性能

分别采用两种不同型号的液晶高分子(LCP)Vectra A950(LCP VA)及Novaccurate(LCP NV)与聚酰胺6(PA6)熔融共混制备PA6/LCP/GF共混物.研究LCP含量及型号对LCP/GF/PA6共混物聚集态结构及力学性能的影响.结果表明:玻纤在复合材料中具有良好的取向,并且呈现出典型的"皮芯"结构;其中含NV组份中玻纤与PA6的界面结合较好,同时LCP也有自身形成微纤结构的趋势.两种LCP对LCP/GF/PA6共混物的拉伸强度影响不大,而弯曲强度和冲击强度随LCP含量的增加有先增加后减小的趋势,其中,当VA含量为10份时弯曲强度达到最大值,为114.9 MPa,比纯PA6提高了36.8%,当NV含量为10份时,冲击强度达到最大值,为4.74kJ/m2,比纯PA6提高了24.7%.     

多壁碳纳米管/热致液晶高分子复合材料的加工及性能研究

通过微型双螺杆挤出机熔融共混和微型注塑机注射成型,制备了多壁碳纳米管/热致液晶高分子(MWC-NT/TLCP)纳米复合材料。红外分析表明,MWCNT表面有一定量羧基。加工流变曲线表明,剪切扭矩随MWCNT用量的增加而升高,经过5min回流共混后,液晶充分塑化。扫描电镜分析表明,MWCNT在基体中均匀分散,并与液晶形成紧密结合的界面。拉伸试验表明,复合材料的模量、强度和断裂伸长率均随着MWCNT的用量的增加而升高。     

含热致液晶高分子的共混体系的粘度与形态结构

综述了含热致液晶高分子的高聚物共混材料粘度与组成的关系,分析了影响共混物形态结构特别是纤维状液晶分散相形成的各种因素。     

加工史对热致液晶高分子/聚碳酸酯共混物力学性能的影响

热致液晶高分子与热塑性塑料共混物不仅具有优异的力学性能和加工性能,而且还具有再加工能力。本文主要考虑了热致液晶高分子 Ku922l和聚碳酸酯(PC)共混物的力学性能与反复加工次数之间的关系,结果表明,该共混物第二次加工时,力学性能有所下降,但下降不多,第三次加工时力学性能显著下降。     

热致液晶高分子与热塑性工程塑料合金的研究进展

对热致液晶高分子 /热塑性高聚物 (TL CP/ TP)原位复合材料的物理机械性能、共混加工、形态结构最新研究进展以及如何改善其共混体系相容性进行了论述 ,同时指出该材料在某些特殊用途的高性能工程塑料的应用前景看好。     

Factors influencing the formation of 2-hydroxy-6-naphthoic acid from carboxylation of naphthol

The synthesis of 2-hydroxy-6-naphthoic acid (2,6-HNA) from carboxylation of alkali-naphthoxide was studied with varying alkali cation types and reaction conditions such as reactant concentration, reaction time, temperature, and pressure. The product selectivity was strongly affected by the types of alkali cation, reaction time, and temperature, while the product yield was governed by reaction pressure. The maximum HNA yield, 28.6%, was achieved with 2,6-HNA selectivity of 81.6% at 6 atm of CO₂, 543 K, and 6 h of reaction. The addition of K₂CO₃ led to further increase in the productivity of 2,6-HNA via suppression of the decarboxylation of HNA.     

溶剂法合成2-羟基-1-萘甲酸的工艺研究

以β-萘酚和氢氧化钠为原料,正辛烷为溶剂,合成了2-羟基-1-萘甲酸,纯度达98％以上。通过正交实验研究了反应压力、反应温度和反应时间对收率的影响,确定了最佳的工艺条件：反应压力0．8MPa,反应温度90℃,反应时间8h,该条件下收率达82．83％。     

The structure of copoly(4-hydroxybenzoic acid/2-hydroxy-6-naphthoic acid): 2. An atomic model for the copolyester chain

X-ray fibre diagrams of fibres drawn from the (liquid crystalline) melts of copoly(4-hydroxybenzoic acid/2-hydroxy-6-naphthoic acid) show meridional maxima that are aperiodic. The positions of these maxima are reproduced in calculations of the meridional intensities for completely random copolymer sequences in which the monomers are approximated to points separated by the appropriate monomer lengths. These calculations have now been extended to consider an atomic model for the chains. Comparison of the calculated meridional transforms with diffractometer scans for five monomer ratios shows good agreement, not only for the positions but also for the relative intensities of the observed and calculated maxima. The linewidth of the maximum at d?2.1 ǎ depends on the chain length used for the calculations and presents a method for determination of the persistence length of the extended chain conformation.     

1,6-二羟基-2-萘甲酸的合成研究

标题化合物是合成新型内分泌治疗剂的重要中间体,而其合成方法未见文献报道。以6-甲氧基-1-萘满酮为起始原料,经取代、氧化和水解3步反应得到目标产物,其结构经MS、~1HNMR、~(13)CNMR和IR确证。该路线原料廉价易得、操作简单、后处理方便,总收率达69.5%,适合工业化生产。     

The structure of liquid crystalline aromatic copolyesters prepared from 4-hydroxybenzoic acid and 2-hydroxy-6-naphthoic acid

X-ray methods have been used to investigate the structure of liquid crystalline copolyesters prepared from 4-hydroxybenzoic acid (HBA) and 2-hydroxy-6-naphthoic acid (HNA). Fibre diagrams and meridional diffractometer scans have been obtained for melt-spun specimens of five HBA/HNA ratios: $\text{25}\text{75}$, $\text{30}\text{70}$, $\text{50}\text{50}$, $\text{58}\text{42}$ and $\text{75}\text{25}$. The data indicate a high degree of axial orientation. The lateral packing is more irregular but the observation of some equatorial and off-equatorial Bragg reflections indicates the presence of some three-dimensional order. The patterns differ in the number and position of the meridional maxima, and these can be predicted accurately by a point model for aperiodic chains of totally random sequence. The sensitivity of the data to monomer ratio is illustrated by calculations across the range of composition from 100% HBA to 100% HNA.     

Synthesis and phase behavior of cholesteric liquid crystal polymers containing glutamic acid in main‐chain

Four polymers (P₀–P₃) containing peptide chain as polymer backbone were synthesized by condensation reaction with bis(trichloromethyl)carbonate and triethylamine. The chemical structures of the monomers M₀–M₃ were confirmed by FTIR and ¹H‐NMR. The structure–property relationships of the monomers and polymers are discussed. Their phase behavior and optical properties were investigated by differential scanning calorimetry, thermogravimetric analysis, and polarizing optical microscopy. Monomers M₁–M₃ and polymers P₁–P₃ displayed cholesteric phases. The results demonstrated that the melt temperature and clear point of monomers (M₁–M₃) and polymers (P₁–P₃) decreased with the increase of the flexible spacer length in the side‐chain, and the mesophase temperature range of the polymers increased with the increase of the flexible spacer length. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

2-羟基-3-萘甲酸生产工艺条件的优化研究

通过对中和及酸析过程的分析,采用改进后的参数指标进行中和及酸析得到的2-羟基-3-萘甲酸,产品为大颗粒、亮黄色,含量98.78%,收率80.13%(以消耗的2-萘酚计),并实现了在大生产中的应用。     

溶剂法合成2-羟基-1-萘甲酸的工艺研究

以β-萘酚和氢氧化钠为原料,正辛烷为溶剂,合成了2-羟基-1-萘甲酸,纯度达98%以上。通过正交实验研究了反应压力、反应温度和反应时间对收率的影响,确定了优化的工艺条件:反应压力0.8 MPa,反应温度90℃,反应时间8 h,该条件下收率达82.83%。     

Conformation in solution of side-chain liquid crystal polymers as a function of the mesogen-graft amount

The conformation of side-chain liquid crystal polymers with different mesogen-graft amounts has been studied by small-angle neutron scattering in dilute solutions of toluene-d8 and THF-d8. It is shown that the radius of gyration increases by about twofold when the mesogen-graft amount increases from 0 to 100%, which suggests that the persistence length of the backbone increases by about 4-fold. Comparison with the results reported in the literature on the melt state suggests that the persistence length is not an intrinsic property of side chain liquid crystal polymers, but depends on inter-chain interactions.     

用于液晶取向材料的聚酰亚胺中间体IPDA的制备

采用一种新的合成路线:以异丙苯为起始原料,首先合成出了2,2-二苯基丙烷,采用高真空蒸馏法提纯产物,找出了最佳的蒸馏条件。再经硝化反应和常压下Pd/C加氢还原后制备出了2,2-双(4-氨基苯基)丙烷(IPDA),经气相色谱分析仪(GC)检测含量达98%以上,GC-MS和DSC确认结构,该化合物可用于制备聚酰亚胺膜材料。