热致液晶共聚酯PET／60PHB的合成及性能研究

通过研究影响ＰＥＴ／６０ＰＨＢ对数比浓粘度的诸多因素，确定了缩聚反应的最佳工艺条件，并在该下合成了对数比浓粘度达０．７以上的ＰＥＴ／６０ＰＨＢ共聚酯，用ＮＭＲ，ＩＲ，ＰＯＭ，ＤＳＣ，ＷＡＸＤ和流变学等方法对其结构和液晶性进行了研究和分析，结果表明，合成的聚合物ＰＥＴ／６０ＰＨＢ（ＹＳＴＬ－１）确系ＰＥＴ与ＰＨＢ的无规共聚酯，属向列相热致液晶，加工试验表明，该共聚酯具有优良的加工流动性，其力学性能，     

凝固浴工艺对聚对苯二甲酰对苯二胺膜性能的影响

将聚对苯二甲酰对苯二胺(PPTA)树脂和浓硫酸进行高温溶解,经过脱泡处理,得到PPTA-H_2SO_4溶液,在凝固浴中凝固制备PPTA膜,研究了凝固浴种类及工艺对PPTA膜的结构与性能的影响。结果表明:在质量分数为7%的H_2SO_4、质量分数为4%的Na OH、H_2O 3种凝固浴中,H_2SO_4凝固浴适合PPTA树脂成膜;PPTA膜最佳凝固浴工艺条件为凝固浴H_2SO_4质量分数7%,凝固浴温度3℃,凝固时间3.0 min,在此条件下PPTA膜具有均匀致密的结构,出现明显的彩色条纹状的液晶现象,热稳定性能最好,其拉伸强度约68MPa,900℃时质量保持率达59.81%。     

超高相对分子质量PPTA树脂及其高模量芳纶的研究

对高相对分子质量聚对苯二甲酰对苯二胺(PPTA)树脂进行了表征,开展了添加超高相对分子质量PPTA树脂与普通相对分子质量PPTA树脂共混进行液晶纺丝得到高强度和高模量芳纶的结构表征与性能试验,同时对芳纶的力学性能与其PPTA树脂相对分子质量的关系进行了研究。结果表明,芳纶的力学性能与其PPTA聚合体的相对分子质量紧密相关,如果PPTA树脂的相对分子质量不够高,加上液晶纺丝和高模量热处理过程分子链的进一步降解,高模量芳纶的制备就无法实现。在系统研究PPTA聚合反应规律,特别是聚合诱导相互转变规律及其影响因素研究基础上,通过调控连续聚合的反应条件,在1 000 t/a连续聚合生产线上制备出比浓对数粘度高达9.2 dl/g的超高相对分子质量PPTA树脂;用超高相对分子质量PPTA树脂与通用级PPTA树脂(比浓对数粘度6.8 dl/g)混合进行纺丝,制备出高强度的芳纶,并进一步热处理得到高强度和高模量的芳纶。     

3，4′-ODA改性PPTA对结构及性能影响的分析

通过添加第三单体3，4′-二氨基二苯醚（3，4′-ODA）对聚对苯二甲酰对苯二胺（PPTA）进行改性，能够使其在极性有机溶剂中聚合并得到聚合物纺丝原液。用元素分析、红外光谱和热重分析的方法来验证和分析聚合体的结构和热性能。实验结果表明：3，4′-ODA的加入量对共聚体的结构和性能均有明显的影响。     

TPC溶液加料低温溶液缩聚合成PPTA的研究

本文详细研究了采用对苯二甲酰氯(TPC)溶液加料(双溶液法)低温溶液缩聚合成聚对苯二甲酰对苯二胺(PPTA)的各种工艺条件对产物对数比浓粘度的影响。结果表明,盐的用量、吡啶的用量和单体浓度与TPC粉末加料具有相同的规律性。由于TPC溶液加料工艺的影响,单体摩尔比、TPC分步加料的使用、溶液放置时间及溶剂在TPC和对苯二胺(PPD)溶液配制时的分配比例等具有其特殊的规律性。在优选的条件下,TPC溶液加料工艺和固体粉末加料工艺一样,可以获得较高对数比浓粘度的PPTA。     

中国石化北京燕山石化公司研究院的聚对苯二甲酰对苯二胺小试通过专家评议

中国石化总公司北京燕山石化公司研究院于1992年初在燕化公司的支持下开始研制溶致液晶全芳香族聚酰胺—聚对苯二甲酰对笨二胺(PPTA),经两年的小试研究,在1立升缩聚釜多,经34批的合成,基本上完成了研制任务,PPTA的对数比浓粘度为4.02～5.95,合成成本估算为185.8元/kg,经中国纺织大学对对数比浓粘度为4.3(3.8～4.7)的PPTA进行试纺,所得纤维纤度为1.4d(1.6dlcx),强度19.7g/d(17.3CN/dtex),模量450g /d(396CN/dtex),断裂伸长4.0％。     

高强高模纤维的4种生产技术

目前已有以下４种新技术用于生产高强高模的“超级纤维”。这类纤维的强度至少要达到１８０ｇ／ｔｅｘ（２０ｇ／ｄ）。１、冻胶纺丝，高倍拉伸制纤工艺。该技术是将一种高分子量聚乙烯溶液湿纺成冻胶状纤维，然后以高牵伸比抽出纤维。用这种工艺生产出的纤维的强度和模量高于目前商业化生产的其它有机纤维，但是由于熔点低，用途受到限制。２、液晶纺丝。该工艺是在半干半湿的状态下利用刚性聚合体的液晶溶液，通过纺丝头牵伸，生产刚性聚合体的高取向结晶体。用这种工艺生产出的代表性产品是对位芳香族聚酰胺纤维。如聚对苯二甲酰对苯二胺…     

高速纺涤纶细旦长丝生产的工艺探讨

本文叙述了用POY-DT工艺线路生产单丝纤度约为1.1dtex涤纶细旦长丝的纺丝、拉伸工艺,并对该细旦丝的织造、染整工艺也作了简单介绍。纺丝工艺主要研究了在生产过程中如何提高熔体均匀性和稳定纺丝条件。拉伸工艺主要研究了细旦POY的结构特征以及对拉伸工艺的影响。实践表明:在高速纺工艺条件下能制出单丝纤度约为1.1dtex的涤纶细旦长丝,并能织造出具有较好仿丝绸风格的织物。     

环氧树脂／液晶固化剂固化反应动力学研究

通过差热分析（DSC）研究了非等温过程环氧树脂／液晶固化剂体系的固化反应动力学,研究了不同配比对固化反应的影响,固化反应转化率与固化温度的关系,计算了固化反应的活化能,确定了环氧树脂／液晶固化剂的固化工艺条件,用偏光显微镜观察了环氧树脂／液晶固化剂／4,4－二氨基二苯砜（DDS）体系在不同温度下固化时的形态。结果表明：液晶固化剂的加入量越大,固化反应速度越快;环氧树脂／液晶固化剂体系固化反应的活化能力为71.5kJ/mol,偏光显微镜观察表明：随着固化起始温度的增加,固化体系的形态由原来的具有各向异性的丝状结构变化为各向同性,液晶丝状条纹消失。     

PPTA及改性PPTA的合成与性能表征

通过在N-甲基吡咯烷酮（NMP）-氯化锂体系中,使用对苯二甲酰氯（TPC）、对苯二胺（PPD）和4,4’-二氨基二苯醚（DAPE）通过低温溶液聚合法合成了聚对苯二甲酰对苯二胺（PPTA）及改性PPTA。并考察了DAPE的用量对聚合体ηinh的影响,对制得的两种类型的芳香族聚酰胺进行了IR、TG、SEM等分析表征。     

合成方法对共缩聚PPTA比浓对数粘度的影响

以4,4’-二氨基二苯醚(ODA)为第三单体对聚对苯二甲酰对苯二胺(PPTA)进行共缩聚改性,研究了共缩聚反应工艺条件对PPTA比浓对数粘度(ηinh)的影响。结果发现,当CaCl2用量为4%-6%时,单体摩尔浓度为0.35-0.45mol/L,爬杆后升温至80-85℃,总的反应时间30—40min,加入Ca(OH)2中和20min,制得的共缩聚PPTA的比浓对数粘度可达到2.50-3.37dL/g。不同的第三单体含量和不同的初始投料比对PPTA溶解性和ηinh有很大的影响。     

Rheological and mechanical characteristics of poly-p-phenylene terephthalamide/nylon molecular and particulate composites

Poly-p-phenylene terephthalamide (PPTA) and nylons (nylon 6, 66, 11, and 12) molecular and particulate composites were examined with emphasis on rheological, mechanical, and morphological characteristics. These molecular composites were prepared by coagulation in water from isotropic ternary sulfuric acid solutions. Upon heating above the crystal melting temperatures of nylons, the molecular composites undergo phase separation and become two-phase particulate composites. Shear viscosity measurements indicate that the viscosity of nylon 6 and 66 systems has increased for an order of magnitude because of the presence of PPTA, but decreased in the case of nylon 11 and 12 systems. PPTA/nylon 6 and 66 systems exhibit yield behavior, particularly with high PPTA contents. Measurements show an extrudate swell of around 1 in all composition ranges and shear rates. Scanning electron microscopic investigations of low PPTA content particulate composites reveal spherical or long fibrillar morphology of PPTA phase dispersed in nylon matrices. Wide angle X-ray diffraction investigations show no preferred orientation in the extrudates, but biaxial orientation in the case of compressed films. The study on mechanical properties of extrudates of 5 to 10 wt.% PPTA compositions exhibits significant improvement in tensile modulus and tensile strength. The heat-treated extrudates show further increase in tensile modulus and tensile strength, as compared with the unannealed samples, but the elongation at break decreases.     

Synthesis and properties of homopolyamide and copolyamides fibers based on 2,6‐bis(p‐aminophenyl)benzo[1,2‐d;5,4‐d′]bisoxazole

A novel aromatic homopolyamide with benzobisoxazole units in the main chain was synthesized with 2,6‐bis(p‐aminophenyl)benzo[1,2‐d;5,4‐d′]bisoxazole and terephthaloyl chloride by low temperature solution polycondensation, the inherent viscosity of which was 1.98 dL/g. The diamine and p‐phenylendiamine with terephthaloyl chloride were used to synthesize the copolyamides. The structures of homopolyamide and copolyamides were characterized by IR spectra, elemental analysis, and wide‐angle X‐ray diffraction. Wide‐angle X‐ray diffraction measurements showed that homopolyamide and copolyamides were predominantly crystallinity. The results of thermal analysis indicated that the thermal stabilities of the copolymer increased with an increase of the molar fraction of benzobisoxazole in the copolymers. The thermal stability of the copolyamides with decomposition temperatures (at 10% weight loss) above 570°C was better than that of poly(p‐phenylene terephthalamide) (PPTA). Fibers of homopolyamide and copolyterephthalamides were spun from lyotropic liquid crystal dope in 100% H₂SO₄. When compared with PPTA fibers prepared under the same conditions, the tensile strengths of copolyamides fibers improved by 20–33% with tensile strengths of 1.81 GPa, tensile moduli of 76 GPa, and elongations at break of 3.8–4.1%, which indicated that copolyamides fibers had outstanding mechanical properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Studies on the semirigid chain polyamide—poly(1,4-phenyleneterephthalamide)

In this article, the polycondensation of terephthaloyl chloride and p-phenylenediamine was systematically studied, including the liquid–crystalline state of the solution and the spinning of poly(1,4-phenyleneterephthalamide) (PPTA). High-molecular-weight PPTA with ε_inh = 5–7 was prepared and the main factors influencing the solution polycondensation of 1,4-phenylenediamine with terephthaloyl chloride were studied in detail. Experimental results showed that the water content of the reaction system, reactant concentration, and volume ratio of mix solvents have a great influence on the inherent viscosity of the poly(1,4-phenyleneterephthalamide) obtained. The highest ε_inh was obtained at 0.3M/liter reactant concentration in a mixed solvent ratio HMPA/DMAC of 4/1 (by volume), at 0.35M/liter reactant concentration in a mixed solvent of HMPA/NMP = 7/3, and at 0.5M/liter of reactant concentration in a mixed solvent of HMPA/THF = 9/1. The water content must be controlled to less than 100 ppm in the polymerization system. In the early stage of the polycondensation process, the ε_inh of the polymer obtained increased rapidly with time. The system gelled within 2 or 3 min, while the monomer conversion reached about 100%. However, the reaction of polycondensation continued after gelation and the ε_inh of the polymer increased appreciably. We have studied the viscosity behavior at 20–155°C for the anisotropic solution of PPTA in 100% sulfuric acid (ε_inh of PPTA 2.5–4.9). Experimental results showed that, at low concentrations the viscosity of isotropic solution increases with the increase of polymer concentration to reach a maxium near the critical polymer concentration, beyond which the solution changes to an anisotropic liquid–crystalline solution. The appropriate spinning region was obtained as shown in the phase diagram determined by viscosity, degree of depolarization anisotropy, and region of thermal depolymerization. Fibers of PPTA with high modulus and high tenacity were obtained by dry-jet wet spinning. The fibers obtained have a tenacity of ～22 g/denier, a modulus of ～600 g/denier, and elongation at break ～3.5%.     

原位缩聚合成含聚芳酰胺/酯的微相复合材料Ⅳ.全芳香聚酰胺与聚砜的微相复合材料制备

以原位缩聚方法合成了PPTA/PSF的微相复合材料。FTIR、DSC等分析结果表明,PPTA/PSF微相复合材料较PPTA/PBT-PTMG分子链间存在着更强的相互作用,PPTA对基体聚合物的力学性能有较大的提高。初步结果表明,加入第三单体双酚A在一定程度上提高了复合材料的抗张强度和断裂伸长率,但是模量有所下降。     

PPTA／尼龙1010分子复合材料流变行为的研究

本文采用共沉淀法制备了聚对苯二甲酰对苯二胺(PPTA)/尼龙1010分子复合材料。测定了PPTA/尼龙1010分子复合材料的流变行为,发现PPTA使尼龙1010的表观熔体粘度变大,且PPTA/尼龙1010分子复合材料的表观熔体粘度对温度的敏感性不象尼龙1010那样突出。     

芳纶热拉伸处理过程对氢键影响的研究

研究了热处理过程对聚对苯二甲酰对苯二胺(PPTA)结构与性能的影响。通过对PPTA纤维升温红外光谱分析可以看出:在较低的热处理温度下,随着温度的升高,发现在3 300 cm~(-1)处—NH—伸缩振动峰向高波数方向移动,峰型变宽,吸收峰强度减弱。采用傅里叶变换红外光谱仪和单丝强度仪、比浓对数黏度等研究发现:经热拉伸处理后的PPTA纤维内部分子间氢键作用力增加,自由氢键数减少,游离的—NH_2含量却增加,纤维比浓对数黏度和强度降低,说明纤维的拉伸强度是由分子间作用力以及分子链段的长度共同作用的。