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1.
以端酰氯基团的热致液晶共聚酯HTH 6和端酚羟基的聚碳酸酯(PC)齐聚物为原料,通过溶液缩聚法制备了含PC和HTH 6的嵌段共聚物,并用IR、POM、DSC、WAXD等手段对共聚物结构、热行为和结晶行为进了表征.DSC和POM结果证明这些嵌段共聚物都属向列型热致性液晶.在280℃以下的温度范围内无相分离,而在较高温度(>280℃)为两相结构.共聚物的结晶结构与HTH 6相同,结晶度随HTH 6含量增加而增加,结晶速度也受到PC含量的影响.  相似文献   

2.
液晶嵌段共聚物PET/60PHB-b-PC的合成及结构与性能   总被引:1,自引:0,他引:1  
采用PET齐聚物的原位乙酰化法通过加入少量乙二醇(EG)合成了端羟基液晶聚合物PET/60PHB,并将其作为大单体,与双酚A及碳酸二苯酯通过熔融酯交换法,进一步制得了液晶嵌段共聚物PET/60PHB b PC.研究了合成规律,并借助粘度测定、DSC、偏光显微镜、X 光衍射和红外光谱分析等手段对合成的液晶嵌段共聚物进行了表征.研究表明,当PET齐聚物的ηinh=005~007dL/g,Ac2O/PHB(mol/mol)=13,EG/PET(mol/mol)=006时能获得颜色、液晶性、溶解性均很好的端羟基液晶聚合物PET/60PHB,以此液晶聚合物为原料,采用合适的配方与工艺,能获得粘度较高、液晶性较好,并且熔体流动性很好的液晶嵌段共聚物PET/60PHB b PC.通过偏光显微镜与X 光衍射观察,证明此嵌段共聚物呈现向列型液晶织构,但其液晶态织构与纯PET/60PHB、PET/60PHB和PC的混合物明显不同.此外,还初步建立了用红外的分析手段鉴定液晶聚合物PET/60PHB端基的方法.  相似文献   

3.
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。  相似文献   

4.
嵌段液晶高聚物对聚醚砜 聚对苯二甲酸乙二醇酯/聚对羟基苯甲酸共混物的增容作用张海良张雪飞王霞瑜(湘潭大学化学化工学院湘潭411105)关键词增容作用,嵌段共聚物,原位复合材料基于热致性液晶高分子(TLCP)的原位复合材料以其高性能及易加工等特点而得...  相似文献   

5.
王勇  吴大诚 《应用化学》1994,11(5):95-97
采用差示扫描量热仪和热台偏光显微镜研究了对羟基苯甲酸(PHB)/聚对苯二甲酸丁二酯(PBT)共聚酯的热转变行为和液晶性。结果表明,PHB/PBT共聚酯呈现多重相转变特征,这与共聚酯中存在不同程度的PBT富微区和PHB富微区有关;当PHB链节含量在20%~80%范围时,共聚酯均呈现向列型液晶特征.  相似文献   

6.
用Instron3211型毛细管流变仪研究了以对羟基苯甲酸(PHB)、对苯二甲酸(TPA)和双酚A(BPA)为单体合成的共聚芳酯液晶熔体的流变性能。结果表明,切变速率、熔体温度及PHB链节含量对切粘度和结构粘度有很大的影响。切变速率在10~103/S、温度295~330℃范围内,共聚酯粘流活化能△Eη为74.5~205.1(kJ/mol)。液晶熔体在剪切流中存在屈服应力τo,随温度升高τo值降低。在低温、低切变速率下,共聚酯熔体的弹性很小,甚至呈现挤出收缩现象。  相似文献   

7.
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’-对苯二甲酰地氧二苯甲酰氯(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,合成的共聚互均为向列型热致液晶,共液晶温度范围在20℃ ̄68℃之间,并随着脂肪  相似文献   

8.
以端酰氯基因的热致液晶共聚酯HTH-6和端酚羟基的聚碳酸酯齐聚物为原料,通过溶液缩聚法制备了含PC和HTH-6的嵌段共聚物,并用IR、POM、DSC、WAXD等手段对共聚物结构,热行为和结晶行为进了表征。DSC和POM结果证明这些嵌段共聚物都属向列型热致性液晶。在280℃以睛的温度范围内无相分离,而在较高温度为两相结构,共聚物的结晶结构与HTH-6相同,结晶度随HTH-6含量增加而增加,结晶速度也  相似文献   

9.
PET-HBT嵌段热致性液晶共聚酯的合成   总被引:1,自引:0,他引:1  
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.  相似文献   

10.
液晶共聚物与PSF原位复合的界面研究   总被引:3,自引:0,他引:3  
合成了两种热致性液晶共聚酯BP—LCP和SDP—LCP,对其熔融指数、取向性作了考察。选用基体聚砜(PSF)与液晶共聚酯进行熔融共混,得原位复合材料。SEM断口形态显示了两种液晶在基体中不同的成纤性,并显示出两相的不相容性。采用FT—IR方法分析了液晶共聚酯与PSF界面间的分子相互作用。进一步研究发现在PSF/BP-LCP原位复合体系中加入含PSF和BP-LCP的嵌段共聚物,其相容性得以改善  相似文献   

11.
以生物基单体2,5-呋喃二甲酸、乙二醇为原料合成聚2,5-呋喃二甲酸乙二醇酯(PEF)。采用熔融酯交换法以PEF聚酯部分取代聚对苯二甲酸乙二醇酯(PET),制备了系列PET-b-PEF嵌段共聚酯。通过核磁共振仪(NMR)、差示扫描量热仪(DSC)、热失重仪(TGA)、X射线衍射仪(XRD)等技术手段表征了共聚酯的结构和性能。结果表明,该系列共聚酯的玻璃化转变温度(Tg)在75.8~80.3℃之间,且随着PEF链段质量分数的增加,PET-b-PEF嵌段共聚酯的Tg先降低后升高,结晶度和熔融温度逐渐降低。当PEF链段含量高于15%时,共聚酯没有结晶峰。该系列共聚酯具有良好的热稳定性,起始分解温度在392.2~407.9℃之间,与所制备的PET起始分解温度403.3℃接近。且当共聚酯中PEF链段含量低于15%时,起始分解温度均在407℃左右,优于PET的热稳定性。  相似文献   

12.
嵌段共聚酯的合成研究   总被引:2,自引:0,他引:2  
采用直接酯化法合成了一系列含间苯二甲酸的PEIT-PEG嵌段共聚酯,研究了聚合时间,聚合效率及聚酯的特性粘度与产物中间苯二甲酸含量及共聚酯分子量的关系,得出适于纺丝工艺及工业化生产的共聚酯分子量和间苯二甲酸的含量。  相似文献   

13.
The block copolyesters of poly(butylene terephthalate)(PBT) and poly(butylene adipate)(PBA) were prepared by a novel two-stage method. In the first stage, high molecular weight PBT and PBA were melt mixed in the presence of 1,4-butanediol at 275 °C. In the second stage, vacuum was applied to raise the molecular weight. The extent of transesterification was controlled by the proportion of 1,4-butanediol. The sequence distribution and the thermal properties of the block copolyesters were characterized by NMR and DSC respectively.  相似文献   

14.
Hydroxy‐terminated poly(pentamethylene p,p′‐bibenzoate) oligomers with different molecular weights were prepared. The poly(pentamethylene p,p′‐bibenzoate) oligomers showed rather high crystallinity, and some of them exhibited a monotropic smectic phase. Block copolyesters with hard segments of poly(pentamethylene p,p′‐bibenzoate) and soft segments of poly(tetramethylene adipate) were prepared by coupling the poly(pentamethylene p,p′‐bibenzoate) oligomer and a poly(tetramethylene adipate)glycol with methylene‐4,4′‐diphenylene diisocyanate in solution. The block copolyesters were characterized by IR, 1H NMR, differential scanning calorimetry, a polarized microscope, and X‐ray diffraction. The thermal transitions of the block copolyesters were dependent on the composition and the molecular weight of the poly(pentamethylene p,p′‐bibenzoate) oligomer used. The hard segments in the block copolyesters showed no liquid crystallinity and exhibited rather low crystallinity or were even amorphous. The molecular weight of the poly(pentamethylene p,p′‐bibenzoate) oligomer used influences the glass‐transition temperature and crystalline properties of the soft segments in the block copolyesters significantly. The effect on the glass‐transition temperature of the soft segments is described as the difference in miscibility between the hard and soft segments. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2626–2636, 2002  相似文献   

15.
In this article, two series of ABA triblock copolyesters composed of poly(l-lactide) A hard blocks and odd-odd aliphatic polyesters as B soft midblock were prepared and compared by various techniques. The results showed that the block structures could be formed without any detectable transesterification, and the composition and molecular weight of the triblock copolyesters could be well controlled by adjusting the feeding ratio of l-lactide monomer to the polyester macroinitiator. It was found that the thermal properties, crystal structure, and spherulitic morphology of the triblock copolyesters depended on the composition and block length. The impact of amorphous and crystalline midblocks on the mechanical properties was compared and discussed. The triblock copolyesters composed of crystalline midblock showed similar ultimate stress and elongation, but higher tensile modulus and yield stress, in comparison with analogous containing amorphous midblock. The triblock copolyester composed of short PLLA hard block and amorphous aliphatic polyester soft midblock displayed typical elastomeric behavior without yield, which is a promising aliphatic polyester thermoplastic elastomer.  相似文献   

16.
The backbone of poly(butylene terephthalate) (PBT) was modified with 2,4:3,5‐di‐O‐methylene‐D ‐glucitol (Glux) using solid‐state modification (SSM). The obtained copolyesters proved to have a non‐random overall chemical microstructure. The thermal properties of these semicrystalline, block‐like, Glux‐based materials were extraordinary, showing higher melting points, and glass transition temperatures compared with other sugar‐based copolyesters prepared by SSM. These remarkable thermal properties were a direct result of the inherently rigid structure of Glux and the relatively slow randomization of the block‐like chemical microstructure of the Glux‐based copolyesters in the melt. SSM proved to be a versatile tool for preparing partially biobased copolyesters with superior thermal properties. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 164–177  相似文献   

17.
A series of copolyesters based on terephthaloyl chloride, hexamethylene glycol and hydroquinone or chlorohydroquinone were prepared. The copolymers showed composition-dependent liquid crystalline properties as verified by visual observation of stir-opalescence, polarizing microscope and DSC. The copolyesters with aromatic diol contents over a certain extent (x≥0.2) were thermotropic with wide liquid crystalline temperature ranges. Comparing with the copolyesters based on butylene glycol or ethylene glycol, the minimum fraction of aromatic diol (x value) used to get the liquid crystallinity for all these copolyesters is around 0.2 regardless of the chain lengths of aliphatic glycols. ~1H-NMP studies revealed that copolyesters have microstructure of block sequence distribution and the mesogenie segments shorter than triad with three phenyl nuclei will not provide the liquid crystallinity.  相似文献   

18.
Furano-Aliphatic copolyesters, such as poly(propylene furanic)-co-(polycaprolactone) (PPF-co-PCL), Poly(propylene furanic)-co-(polylactide) (PPF-co-PLA) and Poly(propylene furanic)-co-(polyglycolide) (PPF-co-PGA) were prepared by ring opening polymerization (R.O.P.) using monomers derived from renewable resources. These copolyesters were characterized by 1H-NMR, DSC and TGA. The degree of randomness determined by 1H-NMR is close to 1, reflecting a random distribution, sometimes less than one. This indicates that these polyesters have a character to block. The hydrolytic degradation of polymers was performed at pH 4.35 at 37°C over a period of four weeks. The oxidative degradation proved a mass loss of about 50%.  相似文献   

19.
本文以对笨二甲酰氯(TC)、对苯二酚(HQ)及不同分子量的端羟基聚砜低聚物(PSF)为原料,通过熔融缩聚法制得了一系列含有聚砜间隔段的三组分嵌段共聚酯。对产物用偏光显微镜下的双折射、搅动乳光和X-光衍射等手段研究了其液晶行为。分别以分子量为1.05×10~3和2.05×10~3的PSF为原料,所得其聚酯出现液晶性所需介晶单元的最小用量各为30和50mol%,若以双酚A(BPA)或双酚S(BPS)残基单元代替PSF基元计算,则为8.3和9.9mol%。  相似文献   

20.
含二羟基二苯酮的系列热致液晶共聚酯的合成和表征──Ⅲ.含4,4'-二羟基二苯砜结构的共聚酯董德文,池振国,倪玉山,丁孟贤(中国科学院长春应用化学研究所长春130022)陈玉(东北师范大学分析测试中心长春130024)关键词4,4'-二羟基二苯酮,热致...  相似文献   

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