一类含萘环结构的聚酯酰亚胺液晶聚合物的结构与性能研究

利用Higashi芳香聚酯直接缩聚法的原理,采用分步投料的方法,以N,N′-1,6-亚己基-双苯偏三酸酰亚胺二酸(IA6)、6-羟基-乙-萘甲酸(HNA)和4,4′-二羟基二苯酮(DHBP)为单体原料,合成了一系列聚酯酰亚胺共聚物.用核磁共振(NMR)、差热分析(DSC)、偏光显微镜(PLM)、广角X射线衍射(WAXD)、热重分析(TGA)等手段对所合成的聚酯酰亚胺的液晶行为、结构以及热性能进行了表征.研究结果表明,当HNA投料量占单体总投料量高于33mol%时,所得聚合物均呈明显的向列型热致液晶特性.但是,此类液晶聚合物仅在升温过程中出现液晶的相转变,而在降温过程中并未观察到液晶的相转变行为.由DSC结果分析可知,此类聚合物具有较高的玻璃化转变温度(Tg)和较低的熔融温度(Tm),有望成为一类既具有较低加工温度又有较高使用温度的液晶聚合物材料.     

固态后缩聚方法合成高分子量的含磷热致性液晶共聚酯

为了获得较高分子量的具有高阻燃性的热致性液晶高分子,通过固态聚合方法合成了一种基于对羟基苯甲酸、对苯二甲酸、乙二醇和含磷菲环取代二酚的高热稳定性、较低相转变温度和宽的液晶相转变温度范围的含磷液晶共聚酯(BDQTEP),并对该含磷液晶共聚酯预聚物(pre-BDQTE)在不同固态聚合条件下获得的聚合物热性能和液晶性进行了研究.对其固态反应速率控制进行了初步的探讨,当反应温度为235℃时,固态聚合反应较为理想.在聚合的初始阶段,共聚酯特性黏数[η]、黏流温度Tf和羧基浓度[COOH]均随聚合时间而明显变化,但在6 h后变化较小,几乎不变.通过固态后缩聚,将熔融聚合获得的特性黏数[η]=0.44 dL/g的含磷液晶共聚酯BDQTE的特性黏数提高了近两倍.     

含柔性间隔基的热致液晶性共聚酯的合成

将己二酸、辛二酸、癸二酸、1,10-十二烷基羧酸经酰氯化后,分别与对羟基苯甲酸合成,得到了四种二元羧酸以及与其相应的四种二元酰氯,并发现前者具有热致液晶性。 将上述单体与对苯二酚、氯代对苯二酚以及联苯二酚用溶液缩聚的方法合成了十二种规则共聚酯,并用热台偏光显微镜、DSC、X-衍射等方法对共聚酯进行了表征。结果发现各共聚酯均为向列型热致液晶,并都具有较宽的液晶态温度范围。通过改变分子结构可使共聚酯的熔点在150—300℃之间变化。     

含柔性间隔基的热致液晶性共聚酯的合成

 将己二酸、辛二酸、癸二酸、1,10-十二烷基羧酸经酰氯化后,分别与对羟基苯甲酸合成,得到了四种二元羧酸以及与其相应的四种二元酰氯,并发现前者具有热致液晶性。 将上述单体与对苯二酚、氯代对苯二酚以及联苯二酚用溶液缩聚的方法合成了十二种规则共聚酯,并用热台偏光显微镜、DSC、X-衍射等方法对共聚酯进行了表征。结果发现各共聚酯均为向列型热致液晶,并都具有较宽的液晶态温度范围。通过改变分子结构可使共聚酯的熔点在150—300℃之间变化。     

含4，4＇－二羟基二苯酮热致液晶四元共聚酯的合成与表征

含４，４＇－二羟基二苯酮热致液晶四元共聚酯的合成与表征董德文，韩平，倪玉山，丁孟贤，韩伟（中国科学院长春应用化学研究所长春１３００２２）（吉林化工学院化工系吉林）关键词　热致液晶，共聚酯，向列型，二羟基二苯酮关于热致液晶芳香族聚酯的研究已有大量的报道...     

PET-HBT嵌段热致性液晶共聚酯的合成

液晶高分子材料具有相当高的强度和模量，被誉为当代超级工程塑料．以对羟基苯甲酸甲酯、1，4-丁二醇为主要原料，经熔融酯交换合成双-对羟基苯甲酸丁二醇酯(BBHB)；以四氯乙烷为溶剂，采用溶液缩聚法将过量的BBHB与对苯二甲酰氯(TPC)合成端基为BBHB的齐聚物(PHBT)；以对苯二甲酸二甲酯与乙二醇为原料，经熔融酯交换合成对苯二甲酸双β-羟乙酯(BHET)，然后采用溶液缩聚法将BHET与少量的TPC合成端基为TPC的齐聚物(PTET)；最后以PHBT与PTET为原料，以四氯乙烷为溶剂，采用溶液缩聚法合成目标共聚酯(PET-HBT)。研究了共聚酯的双折射现象及热行为；用偏光显微镜观察了试共聚酯的织态结构并用FTIR表征了共聚酯的微观结构．     

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.     

1,8-辛二酸改性热致液晶共聚酯的制备及其性能

以对羟基苯甲酸、对苯二甲酸和对苯二酚为共聚单体，经乙酰化和熔融缩聚两步法合成三元热致液晶共聚酯。引入长链脂肪族化合物1,8-辛二酸作为改性单体，按不同比例代替对苯二甲酸，制备了一系列含柔性链段的新型四元热致液晶共聚酯。通过傅里叶红外光谱(FT-IR)和核磁共振碳谱(¹³C-NMR)对共聚酯结构进行表征，采用差示扫描量热(DSC)和热失重分析(TGA)表征其热性能，采用偏光显微镜(POM)和X射线衍射(XRD)分析其液晶性能。研究表明，三元液晶共聚酯熔点达407℃，热稳定性优异。随着1,8-辛二酸含量增加，四元共聚酯熔点显著降至214℃，热稳定性较好，最大热分解温度达到428℃。该系列共聚酯显示了典型的向列型液晶织态结构。1,8-辛二酸的引入显著改善了液晶共聚酯的可加工性。     

4,4’-对苯二甲酰基二氧二苯甲酸与脂二醇的共聚及液晶性能研究

以对苯二甲酸和对羟基苯甲酸为起始原料合成了液晶单体4，4’-对苯二甲酰二氧二苯甲酰氯（TOBC），用TOBC分别与癸二醇-1，10，己二醇-1，6，戊二醇-1，5，丁二醇-1，4和乙二醇进行缩聚反应，生成了一系列主链型热致液晶共聚酯。用DSC、热台偏光显微镜和X-射线衍射仪等对合成的共聚酯的液晶行为进行了表征，结果表明，合成的共聚酯均为向列型热致液晶，其液晶温度范围在20℃－68℃之间，并随着脂肪族二醇中亚甲基（CH2）单元的增加，共聚酯的熔融转变温度（Tm）和各向同性温度（Ti）均有规律的变化。表明主链型液晶共聚酯分子中柔性间隔基的大小对共聚酯的液晶性质有着明显的影响。     

含X-型和棒型两种液晶基元的主链型共聚酯

采用高温溶液缩聚方法,合成了一系列不同配比的含X-型和棒型两种液晶基元的主链型芳族共聚酯。经检测,所有样品均具有热致液晶性。本文对这类共聚酯的液晶行为进行了研究。     

Synthesis and comparative biodegradability studies of three poly(alkylene succinate)s

Poly(alkylene succinates) were synthesized from succinic acid and aliphatic diols with 2 to 4 methylene groups by melt polycondensation. DSC, ¹H NMR, WAXD and molecular weight measurements were used to characterise the polymers. Biodegradability studies of polyesters with the same average molecular weight, included enzymatic hydrolysis for several days using Rhizopus delemar lipase at pH 7.2 and 30 °C. DSC traces of biodegraded polyesters revealed that hydrolysis affected mainly the amorphous material. For all polyesters an increase in glass transition, melting point and heat of fusion was recorded. In the first days of enzymatic hydrolysis, fast rates of mass loss were observed accompanied by a rapid reduction of intrinsic viscosity and molecular weight, thus indicating a mixed endo- and exo-type hydrolysis mechanism. Afterwards, it turned to an exo-type mechanism, taking place in the crystalline phase, since after 15-25 days of enzymatic hydrolysis molecular weight was stabilized, while mass loss kept on decreasing though in a slower rate. End-group analysis revealed that carboxyl and hydroxyl groups increased due to ester bonds' scission. The biodegradation rates of the polymers decreased following the order PPSu > PESu ≥ PBSu and it was attributed to the lower crystallinity of PPSu compared to other polyesters, rather than to differences in chemical structure. Finally, a simple theoretical kinetic model was developed and Michaelis-Menten parameters were estimated.     

Melt‐processable poly(oxyphenylalkanoate): Synthesis,properties, and in vitro degradation of poly(4‐oxyphenylacetate)

The homopolyester of 4‐hydroxyphenylacetic acid (HPAA) was synthesized by one‐pot, slurry‐melt, and acidolysis melt polymerization techniques and was characterized by its inherent viscosity and IR and NMR spectra. Differential scanning calorimetry (DSC), polarizing light microscopy (PLM), and wide‐angle X‐ray diffraction (WAXD) studies of the homopolymer were carried out for its thermal and phase behavior. The results indicated that the yield and molecular weight of the polymer depended on the method of preparation; moreover, the acidolysis melt polymerization of the pure acetoxy derivative of HPAA was the best method for the preparation of high molecular weight poly(4‐oxyphenylacetate) (polyHPAA) without side reactions. DSC and PLM studies also showed that the thermal and optical properties depended largely on the polymerization conditions and inherent viscosity values. PolyHPAA did not show a clear texture typical of liquid‐crystalline polymers, whereas after cooling from the melt, structures similar to spherulitic crystals were observed. WAXD patterns showed a crystalline nature. The in vitro degradability of the polymer was also studied via the water absorption in buffer solutions of pH 7 and 10 at 30 and 60 °C; this was followed by Fourier transform infrared, inherent viscosity, DSC, thermogravimetric analysis, WAXD, and scanning electron microscopy techniques. Unlike Vectra®, which showed no degradation, polyHPAA showed an increase in hydrolytic degradation from 5.0 and 6.0% at 30 °C to 12.5 and 15.0% at 60 °C after 350 h in buffer solutions of pH 7 and 10, respectively. The results indicated a possible biomedical prosthetic application of poly(oxyphenylalkanoate)s such as polyHPAA with better crystallinity coupled with degradability as a substitute for poly(hydroxyalkanoates). © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2430–2443, 2001     

Synthesis and ring-opening copolymerization of cyclic aryl ester dimers

Two kinds of cyclic aryl ester dimers have been synthesized by reaction of phthaloyl dichloride with bisphenols via interfacial polycondensation. The cyclic dimers readily undergo anionic ring-opening polymerization or copolymerization in the melt by using sodium benzoate as the initiator, producing linear, high molecular weight polyesters. The contents of cyclic dimers in the homopolymers P1, P2, and copolymer P12 are 13.7%, 10.2%, 2.9%, respectively, which indicates that ring-opening copolymerization of cyclic dimers may impel the conversion of cyclic dimers and decrease the content of cyclic dimers in the resulting copolymer. Moreover, the isothermal chemorheology of the ring-opening copolymerization of cyclic dimers indicates that the reactivemoltenmixture has low shear viscosity and the viscosity increases slowly in the initial stage of ring-opening polymerization.     

Polymorphic Behavior of Syndiotactic Polypropylene Induced by Heat Treatment

The polymorphic behavior of syndiotactic polypropylene (s-PP) crystallized from the melt under different conditions was investigated by means of WAXD and DSC. The isothermal melt crystallization of s-PP proceeded in form I at tc≥ 110℃ and in form Ⅱ at tc≤110 ℃ s-PP crystallized nonisothermally from the melt was the mixture of forms and . With increasing the cooling rate (a), the content of form increased, and the content of form decreased. On heating, at 10 K/min, of quenched s-PP, it crystallized in form at t≤70 , continuing heating resulted in form form transition, which was an endothermal process.     

聚(丁二酸丁二酯-co-丁二酸丙二酯)的等温结晶行为研究

以1,4-丁二酸、1,4-丁二醇和1,3-丙二醇为原料通过直接熔融缩聚法合成了聚丁二酸丁二酯(PBS),聚丁二酸丙二酯(PPS)和聚(丁二酸丁二酯-co-丁二酸丙二酯)(PBSPS)等脂肪族聚酯.利用1H-NMR,WAXD,DSC和POM等研究了聚酯的结晶结构和结晶动力学过程等结晶行为.PBSPS的结晶晶型与PBS一致,说明只有丁二酸丁二酯(BS)单元结晶而丁二酸丙二酯(PS)单元处于无定形区.聚酯等温结晶后,在升温熔融过程中出现了多重熔融峰.分析表明多重熔融峰主要来自于聚酯升温过程中的熔融-重结晶行为.利用Avrami方程分析了聚酯的等温结晶动力学,Avrami指数n为2.2~2.8,说明聚酯等温结晶时主要以异相成核的三维生长方式进行;随着PS单元的增多,聚酯的表观结晶活化能升高,也就是说BS单元的结晶变得困难.POM观察到聚酯等温结晶时都出现了环带球晶现象,球晶形态会随着结晶温度和化学结构差异而改变.     

聚β-羟基丁酸酯顺丁烯二酸酐接枝共聚物的研究

采用DSC、TGA、POM和WAXD等方法对聚 β 羟基丁酸酯 (PHB)及其接枝顺丁烯二酸酐共聚物 (PHB g MA)的结晶行为、热稳定性和生物降解特性进行了研究 .结果表明接枝产物的热稳定性明显优于PHB ,热分解温度提高了 2 0余度 ;结晶行为发生很大的变化 .结晶速率减小 ,结晶温度降低 ,冷结晶温度升高 ,球晶的织态结构也随着MA接枝量的变化发生明显变化 ,并且接枝MA促进了PHB的生物降解     

Synthesis and thermal characterization of poly(1,3-phenyl octanoate)

Poly(1,3-phenyl octanoate) (polyHPOA) was prepared by melt and solution polycondensation methods from 8-(3-hydroxyphenyl)octanoic acid (HPOA), a novel monomer useful as a chain disruptor in liquid crystalline copolyesters. The melt polycondensation technique gave a polyester of higher inherent viscosity (0.80 dL/g in p-chlorophenol) than that (0.75 and 0.56 dL/g, respectively, for the Ogata method and thionyl chloride/pyridine method in the same solvent) of solution techniques. The solubility of the polyesters was limited to strongly acidic and polar solvents. The polyester was characterized by elemental analysis, IR spectroscopy, WAXD, TGA, isothermal TGA and DTA. x-ray diffraction pattern of the polyesters indicated that it is amorphous in nature. TGA of the polyesters gave a thermal stability of 470°C in nitrogen atmosphere at 50% decomposition. The available thermal data suggest that the polyester undergoes thermal decomposition by a pyrolytic cleavage involving the ester linkage with the formation of ketene and phenol ended groups as intermediates. © 1996 John Wiley & Sons, Inc.     

Synthesis and characterization of new cardo polyesters

New phthalide-containing bisphenols, phenolphthalein-N-(3-methylanilide) (3-PMA), and phenolphthalein-N-(4-methylanilide) (4-PMA), were synthesized from phenolphthalein and m- and p-toluidines. These bisphenols were polycondensed with terephthaloyl chloride (TPC) using an interfacial or solution polymerization technique to yield new polyesters. Copolymers were also obtained by utilizing different molar proportion of phenolphthalein (PPH) and 3-PMA or 4-PMA with TPC. The polymers prepared by solution polymerization were obtained in 93–99% yields and showed reduced viscosities in the range 0.37–0.83 dL/g. They were readily soluble in chlorinated hydrocarbons and aprotic polar solvents. The polyesters showed glass transition temperatures in the range 261–300°C as measured by DSC. Thermogravimetric analysis of the polyesters indicated no weight loss below 408°C under N₂ atmosphere. Structure–property correlations among these cardo polyesters have been discussed. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3227–3234, 1997     

基于己内酰胺和乙醇胺的聚酯酰胺合成及表征

以己内酰胺及乙醇胺进行开环聚合,合成了聚酰胺预聚物(PrePA),并采用N,N'-碳酰双己内酰胺(CBC)和1,4-双(2-噁唑啉)苯(PBOX)对其进行了扩链反应.进一步将PrePA与己二酸缩聚,制备了聚酯酰胺预聚体(PrePEA),以CBC和PBOX复合扩链剂扩链,获得了特性黏数达0.74 dL/g的聚酯酰胺.并采用红外、核磁及WAXS对聚合物的结构和晶型进行了表征,以DSC和TGA测定了聚合物的热性能,同时对聚合物的力学性能进行了测定.     

ADVANCES IN LIQUID CRYSTALLINE POLYESTERS

Advances have been made in understanding the interactions of composition, molecular weight, liquid crystallinity,orientation, and three-dimensional crystallinity on the properties of injection-molded and melt-spun liquid crystalline polyesters (LCP's). Two classes of potentially low-cost LCP's were compared:(1) semiflexible LCP's prepared from 1,6-hexanediol and the dimethyl ester of either trans-4, 4'stilbenedicarboxylic acid or 4.4 ' biphenyldicarboxylic acid and (2) all-aromatic LCP's prepared from terephthalic acid, 2, 6-naphthalenedicarboxylic acid, the diacetate of hydroquinone, and the acetate of p-hydroxybenzoic acid. The effects of composition on the plastic properties of the 4-component all-aromatic LCP's were determined with the aid of a 3 x 3 factorial statistically designed experiment, the generation of equations with a computer program, and the plotting of three-dimensional figures and contour diagrams. The effects of absolute molecular weight (M_w) on the tensile strengths of the semiflexible LCP's and one of the all-aromatic LCP's having an excellent balance of plastic properties were also compared, and it was observed that the semiflexible LCP's required M_w's about 4 times higher than the all-aromatic LCP to attain a given strength. Persistence lengths and molecular modeling were used to explain these differences.