新型聚丙烯酸酯侧链液晶的合成

以对-羟基苯甲酸、氯乙醇和丙烯酸为主要原料，经醚化、酯化和酰氯化反应合成了中间体A、B、C，进而合成了含液晶基元的丙烯酸酯单体D；用单体D经自由基聚合反应合成了聚丙烯酸酯侧链液晶；分别对中间体A、B、C和单体D以及聚合物进行了表征。结果表明：单体和聚合物均呈现向列型液晶织态结构，聚合物在较宽的温度范围内有很好的液晶性。     

原位聚合二胺盐液晶单体及其聚合物电化学性能的研究

以苯甲酸联苯酯为基元,制备二胺盐液晶单体。对液晶单体紫外光致原位聚合制备出具有离子传导功能的聚合物。通过FT IR和~1H NMR对其结构进行了表征。通过电化学工作站测试其电阻并计算出不同温度下的离子传导率。结果表明,由于液晶态下分子结构的有序排列,二胺盐液晶单体在液晶态的传导率高于固态的传导率,并且传导率随着温度的升高而上升,在170℃达到最大值,为1.30×10~(-5)S/cm。二胺盐聚合物在95℃下传导率达到1.02×10~(-5) S/cm。通过原位聚合使聚合物保留单体在液晶态时的分子有序排列,获得在中低温条件下传导率接近液晶相下传导率的聚合物材料。     

一种手性薄荷单体对侧链液晶聚合物性能的影响研究

由非液晶手性薄荷单体M1和胆甾醇类液晶单体M2与聚甲基含氢硅氧烷（PMHS）接枝共聚合成了系列新型侧链液晶聚合物。运用红外光谱分析（FTIR）、氢核磁共振谱分析（1H NMR）、差示扫描量热分析（DSC）、热失重（TG）分析、偏光显微分析（POM）、旋光分析（SORT）和X-射线衍射分析（XRD）等进行表征。单体M2在升温和降温过程中呈现胆甾相液晶织构，M2均聚物P1为手性近晶A相，P2～P7为胆甾相液晶。实验结果显示，随着单体M1含量的增加，聚合物的左旋光活性越来越强，玻璃化温度强呈现先降低后升高趋势，清亮点温度Ti降低，液晶相范围变窄。     

含异山梨醇和胆甾醇的侧链胆甾型液晶聚合物的合成与表征

异山梨醇类单体和胆甾类液晶单体与聚甲基含氢硅氧烷（PMHS）接枝共聚合成系列新型胆甾型侧链液晶聚合物。运用红外光谱（FTIR）、核磁共振谱（1HNMR）、差示扫描量热分析（DSC）、热失重分析法（TG）和偏光显微分析法（POM）等进行表征。单体M1和M2在升、降温过程中均呈现胆甾相液晶织构,聚合物P1～P7为胆甾相液晶。实验结果髭示,较低的玻璃化转变温度使得聚合物具有广阔的应用前景,随着胆甾液晶组分的增加,聚合物的玻璃化转变温度降低,清亮点先降低后升高,液晶相范围起初变化缓慢后变化很快。     

胆甾相液晶与向列相液晶共聚物的制备及液晶性能的研究

合成了向列相液晶单体4-乙氧基苯甲酸-4’-烯丙氧基联苯酯(M1)和胆甾相液晶分子4-(4-烯丙氧基苯丙酰氧基)-苯基苯氧羰基戊酸胆甾醇酯(M2),把液晶分子根据不同的浓度配比分别和聚甲基含氢硅氧烷接枝共聚,合成了具有不同化学结构和性能的侧链型液晶聚合物。并利用红外光谱(FT-IR)、热失重分析(TGA)、差示量热扫描分析(DSC)、偏光显微法(POM)和旋光仪等测试手段对其迚行了表征。结果表明:随着单体M2含量的增加,聚合物的比旋光度随之增加;熔融温度和清亮点随M2含量的增加而降低;偏光照片显示P1为典型的向列相液晶;M2液晶分子引入后,P2-P7为典型的胆甾型液晶。     

聚氨酯丙烯酸酯体系PDLC膜的制备及性能研究

本文以聚氨酯丙烯酸酯为预聚物,使用甲基丙烯酸十八烷基酯、甲基丙烯酸月桂酯、丙烯酸二甲基氨基乙酯、丙烯酸丁酯等作为稀释剂,通过相分离的方法将液晶和聚合物混合后,在紫外光的照射下,制备聚合物分散液晶膜。并在此方法下,探索了不同稀释剂单体、不同含量预聚物、液晶、光引发剂等混合的条件下所制备的PDLC材料性能。     

含乙烯基末端的液晶二聚体的合成与液晶行为研究

合成了一种新型的末端含不饱和双键的席夫碱类液晶化合物,分子结构中含有刚性酯类液晶基元及亚胺间隔基结构,并通过扫描量热(DSC)和偏光显微镜(POM)对其介晶相转变行为进行了表征。结果表明该二聚体与单体表现出不同的液晶行为,二聚体不仅具有向列相(N)液晶结构(120~139℃),且在低温区间显示出层状的近晶C型(SmC)液晶结构(91~120℃),液晶稳定性明显高于单体(单体液晶相温度范围为45~64℃)。实验结果为合成稳定的液晶化合物提供了实验依据。     

一种新型热致性液晶聚酯酰亚胺的合成与表征

在Higashi直接缩聚法的基础上,利用分步投料法,以N,N-己二撑-1,6-双苯偏三酸酰亚胺二胺(IA6)、对羟基苯甲酸(PHB)和对苯二酚二对羟基苯甲酸酯(PHQ)为主要原料,合成了一种新型三元共聚液晶聚酯酰亚胺(IA6PP)。采用FTIR、DSC、TGA、POM和WAXD等方法研究了单体种类对所合成的聚合物结构和性能的影响。结果表明:IA6PP呈现出典型的向列型液晶的特征,液晶温度区间为252~365℃,热稳定性明显高于由4,4-二羟基二苯甲酮(DHBP)、IA6和PHB合成的液晶聚酯酰亚胺(IA6PD)。     

智能调光聚合物分散液晶膜的研发

传统的显示器件在操作的过程中过于复杂,对制样条件的要求较高,为此研发智能调光聚合物分散液晶膜。建立智能调光聚合物分散液晶膜的制备方法。采用相分离温度技术调制聚合物中液晶挥发的现象,保证在最大限度内将聚合物和液晶中稀释出来。根据聚合物分散液晶膜的两相体系,通过利用液晶膜的特征,实现智能调光聚合物分散液晶膜的研发。     

液晶聚合物的注射成型技术

叙述了特种工程塑料液晶聚合物的结构、性能特点及应用；介绍了液晶聚合物制品和模具的设计应考虑的因素；重点阐述了液晶聚合物制品的注射成型工艺，包括原料干燥、料筒温度、注射压力和速度、嵌件预热模具温度、成型周期和注意事项。     

Synthesis and characterization of a thermotropic liquid crystalline hyperbranched polyester

BACKGROUND: Hyperbranched polymers have received increasing attention in the fields of medicine, homogeneous catalysis and materials science. Hydroxyl‐functional aliphatic polyesters are one of the most widely investigated families of hyperbranched polymers. The research reported here is based on the preparation of a novel hyperbranched polyester and the modification of its terminal hydroxyl groups by biphenyl mesogenic units. RESULTS: 2,2,6,6‐Tetramethylolcyclohexanol as a core and 8‐[4′‐propoxy(1,1‐biphenyl)yloxy]octanoic acid as a mesogenic unit were synthesized. A hyperbranched polyester (HPE) was synthesized in one step and subsequently substituted by reaction of its terminal hydroxyl groups with the biphenyl mesogenic units to yield a novel liquid crystalline hyperbranched polyester (HPE‐LC). The chemical structures of all compounds were confirmed using Fourier transform infrared, ¹H NMR and ¹³C NMR spectroscopy. The thermal behavior and the mesogenic properties of the biphenyl mesogenic unit and HPE‐LC were investigated using differential scanning calorimetry, polarized optical microscopy and wide‐angle X‐ray diffraction. The results demonstrated that the degree of branching of the HPE is ca 0.63. Both HPE‐LC and the biphenyl mesogenic unit exhibit mesomorphic properties, but HPE‐LC has a lower isotropic transition temperature and a wider transition temperature range than the biphenyl mesogenic unit. CONCLUSION: A novel liquid crystalline hyperbranched polyester was successfully synthesized, which exhibits mesomorphic properties. This polymer has good solubility in highly polar solvents and good thermal stability. Copyright © 2009 Society of Chemical Industry     

Synthesis and phase behavior of nematic liquid‐crystalline elastomers derived from smectic crosslinking agent

A mesogenic crosslinking agent M‐1 was synthesized to minimize the perturbations of nonmesogenic crosslinking agent for liquid‐crystalline elastomers. The synthesis of side‐chain liquid‐crystalline elastomers containing a rigid mesogenic crosslinking agent M‐1 and a nematic monomer M‐2 was described by a one‐step hydrosilylation reaction. The chemical structures of the obtained monomers and network polymers were confirmed by Fourier transform infrared and ¹H‐NMR spectroscopy. The mesomorphic properties and phase behavior were investigated by differential scanning calorimetry, polarizing optical microscopy, and X‐ray diffraction measurements. The influence of the crosslinking units on the phase behavior was discussed. The liquid‐crystalline elastomers containing less than 15 mol % of the crosslinking units showed elasticity, reversible phase transition, and threaded texture. The experimental results demonstrated that isotropic temperature and liquid‐crystalline range of polymers P‐1–P‐7 decreased a little as the concentration of crosslinking agent M‐1 increased, and the use of mesomorphic crosslinking agent M‐1 promotes the arrangement of liquid‐crystalline units from P‐1 to P‐5. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1712–1719, 2005     

Thermotropic liquid crystalline polyphenylphosphates containing aryl ester mesogens

A series of main‐chain liquid crystalline polyphosphate esters with varying center core in a triad ester mesogen were prepared. The phosphorus is incorporated in the middle of the spacer unit. All the monomers and polymers were characterized by spectral and thermal techniques. Thermogravimetric analysis shows that these polymers were stable up to 295–340°C. The char yields of the polymer were in range of 11–31%. Differential scanning calorimetry (DSC) thermal analysis confirms the mesophase formation of the polymers. Some of the polymers exhibited micro‐grainy textures with low glass transition. The DSC and microscopic analysis reveal that the polymer containing central unit which increases the aspect ratio shows liquid crystalline properties, whereas the unit that decreases the aspect ratio failed to show the mesophase formation. Energy minimized structures for the mesogenic units reveal that the polymers containing phenyl, pyridazine, diphenyl ester, and biphenyl unit shows high aspect ratio compared to nonmesogenic phenolphthalein, bisphenol‐A, and bisphenol‐S units. It revealed that increasing the length of the mesogen and incorporating heteroatoms in the aromatic moiety increased the mesophase stability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3924–3930, 2007     

Synthesis and structure of polysiloxane liquid crystalline elastomers with a mesogenic crosslinking agent

A new mesogenic crosslinking agent M‐1 was synthesized to minimize the perturbations of a nonmesogenic crosslinking agent for liquid crystalline elastomers. The synthesis of new side‐chain liquid crystalline elastomers containing a rigid mesogenic crosslinking agent M‐1 and a nematic monomer M‐2 is described by a one‐step hydrosilylation reaction. The chemical structures of the obtained monomers and elastomers were confirmed by ¹H NMR and FTIR spectroscopy. The mesomorphic properties and phase behavior were investigated by differential scanning calorimetry, polarizing optical microscopy, and X‐ray diffraction measurements. The influence of the crosslinking units on the phase behavior is discussed. The elastomers containing less than 15 mol % of the crosslinking units showed elasticity, reversible phase transition, and nematic‐threaded texture. However, when the crosslinking density reached 21.6 mol %, the mesophase of polymer P‐8 disappears. The adoption of a mesogenic crosslinking agent diminishes the perturbation of a nonmesogenic crosslinking agent on mesophase of liquid crystalline elastomers, and isotropic temperature and a mesomorphic temperature range slightly decreased with increasing content of the crosslinking agent. In addition, X‐ray analysis shows nematic polydomain network polymers can transform into smectic monodomain by stress induction, leading to the orientation formation macroscopically. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1736–1742, 2004     

New thermochromic liquid–crystalline polymer: Synthesis and phase behavior

A series of new thermochromic side‐chain liquid–crystalline polymers were prepared. The chemical structures of the resulting monomers and polymers were characterized by element analyses, FTIR, ¹H‐NMR, and ¹³C‐NMR. Their mesogenic properties were investigated by differential scanning calorimetry, thermogravimetric analyses, polarizing optical microscopy, and X‐ray diffraction measurements. The influence of the content of dye groups on phase behavior of the polymers was discussed. The polymers P₁–P₃ showed smectic phase, and P₄–P₇ revealed cholesteric phase. The polymers containing less than 30 mol % of the dye groups showed good solubility, reversible phase transition, wider mesophase temperature ranges, and higher thermal stability. Experimental results demonstrated that the clearing temperature and mesophase temperature ranges decreased with increasing the concentration of the dye groups. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 329–335, 2005     

Investigation on stilbene‐ and azobenzene‐based liquid crystalline organophosphorus polymers

Two series of combined liquid crystalline polyphosphates bearing dual photoreactive mesogenic units (stilbene and azobenzene/α‐methylstilbene and azobenzene) were synthesized by solution polycondensation method. The structures of the synthesized polymers were confirmed by various spectroscopic techniques. Thermogravimetric analysis reveals that they are stable between 230 and 320°C. Differential scanning calorimetry studies were done to study the liquid crystalline property, and glass‐transition, melting, and isotropization temperatures for all the polymers. Polarizing optical microscope shows the birefringent melt for all the polymers exhibiting liquid crystalline property. The photochemical response was studied by UV–visible and fluorescence spectroscopy for all the polymers. The photocrosslinking reaction of the stilbene containing polymers was ascertained by spectroscopic and photolysis studies. The rate of the switching time for the conversion of trans to cis form of azobenzene unit was investigated by UV spectroscopy. The terminal substituents in the side chain affects the texture of liquid crystalline phase for all the polymers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis, thermal and optical properties of liquid crystalline terpolymers containing azobenzene and dye moieties

The synthesis, thermal properties and photochemical and photophysical studies of new azopolymers are described. These polymers contain three different types of monomer, each of which is mainly responsible for a particular function: A mesogenic benzanilide, a photochromic azobenzene and a dye unit (a benzoxazole, an anthracene or a stilbene derivative). This approach provides liquid crystalline terpolymers with different spectral properties and with the potential ability to be photoaligned by irradiation and thermotropic self-organization. The polymers have been prepared by random radical polymerisation of the corresponding methacrylate-fucntionalised units. All of the materials show good thermal stability and liquid crystalline behaviour, displaying smectic A or nematic mesophases. Optical properties of the polymers in solution display additive bands in the absorbance spectrum and luminescent properties in the emission region of the individual dye monomers. However, films of these polymers are not luminescent. A study of the absorption and redox properties of the dyes has been performed in order to evaluate the quenching process in the polymers.     

Silicone‐based cholesteric liquid crystalline polymers: Effect of crosslinking agent on phase transition behavior

Silicone‐based cholesteric liquid crystalline polymers (ChLCP) were fabricated with variable clearing temperatures as controlled by their chemical compositions. The chemical structures of the mesogenic monomers and ChLCP were confirmed by FTIR and ¹H‐NMR spectroscopy. The mesogenic properties and phase behavior were investigated by differential scanning calorimetry, polarizing optical microscopy, and X‐ray diffraction measurements. The experimental results demonstrated that the glass transition temperatures and the clearing points of the liquid crystalline polymers decreased with increasing proportion of mesogenic crosslinking agent up to 12.50 mol % (LCP‐3), and at higher proportion of crosslinking agent, the clearing points disappeared, indicating that the network chains have less chance to orient themselves. Thermogravimetric analysis showed that the LCP‐3 was the most stable up to 230°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of new ferroelectric liquid‐crystalline cyclic oligosiloxanes containing methyleneoxymethylene spacers

The synthesis of side‐chain liquid‐crystalline oligocyclosiloxanes containing methyleneoxymethylene spacers, two different mesogenic cores (including biphenyl phenyl carboxylate or biphenyl fluorophenyl carboxylate groups) and chiral tails is presented. Differential scanning calorimetry, optical polarizing microscopy and X‐ray diffraction measurements reveal liquid‐crystalline properties for all of the synthesized monomers and oligomers. All cyclic oligosiloxanes exhibit enantiotropic smectic A and chiral smectic C phases. The mesogenic properties of the cyclic oligomers and side‐chain liquid‐crystalline precursor are discussed. Copyright © 2005 Society of Chemical Industry     

Study on a series of main-chain liquid–crystalline ionomers containing sulfonate groups

A series of main-chain liquid–crystalline ionomers containing sulfonate groups pendant on the polymer backbone were synthesized by an interfacial condensation reaction of 4,4′-dihydroxy-α,α′-dimethyl benzalazine, a mesogenic monomer, with brilliant yellow (BY), a sulfonate-containing monomer, and a 1/9 mixture of terephthaloyl and sebacoyl dichloride. The structures of the polymers were characterized by IR and UV spectroscopies. DSC and thermogravimetric analysis were used to measure the thermal properties of those polymers, and the mesogenic properties were characterized by a polarized optical microscope, DSC, and wide-angle X-ray diffraction. The ionomers were thermally stable to about 310 °C. They were thermotropic liquid–crystalline polymers (LCPs) with high mesomorphic-phase transition temperatures and exhibited broad nematic mesogenic regions of 160–170 °C, and they were lyotropic LCPs with willowy leaf-shaped textures in sulfuric acid. However, the thermotropic liquid–crystalline properties were somewhat weakened because the concentration of BY was more than 8%. The inherent viscosity in N-methyl-2-pyrrolidone suggested that intramolecular associations of sulfonate groups occurred at low concentration, and intermolecular associations predominated at higher concentration. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2210–2218, 2001