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含有草酸酯的共聚酯的合成与性能研究 总被引:3,自引:0,他引:3
以草酸二乙酯(DEOX)为原料,采用熔融缩聚法制备了草酸乙二醇酯与对苯二甲酸乙二醇酯、癸二酸乙二醇酯的无规共聚酯(PETOXS)。考察了共聚酯的热性能、水解性能和拉伸性能。结果表明,共聚酯的熔点、结晶行为依赖于组成,芳香族聚酯含量少的共聚酯的热分解温度受两种脂肪族聚酯单元组成的影响。PET含量多,共聚酯的水解性能差;而聚草酸酯含量高,水解快、模量高、应变小。 相似文献
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由直接酯化法制备了不同1,4-环己烷二甲醇(CHDM)含量的聚对苯二甲酸乙二醇酯-聚对苯二甲酸-1,4-环己烷二甲醇酯(PET-PCT)共聚酯;利用核磁共振表征了合成产物的实际组成及序列结构;采用差示扫描量热和热失重分析研究了共聚酯的结晶特性和热稳定性。结果表明:合成的共聚酯为无规嵌段聚合物,PCT的实际组成均高于投料比,各链段的序列长度与其含量成正比。随着CHDM含量的增加,共聚酯的玻璃化转变温度升高,退火后的试样在低温处和高温处出现了两个熔点,且熔点和焓值随PCT含量的增加而降低。合成产物热稳定性优良,起始分解温度均大于400℃,最大分解温度大于435℃。用Friedman法对热分解动力学的分析,进一步证明共聚酯的热稳定性优良。 相似文献
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以对苯二甲酸、乙二醇以及聚四氢呋喃(PTMG)为原料,采用熔融缩聚法合成了不同PTMG比例的聚对苯二甲酸乙二醇酯-聚四氢呋喃(PET-PTMG)聚醚酯,研究了PTMG含量对共聚酯缩聚反应过程的影响。利用红外光谱法、核磁共振波谱法分析了共聚酯结构、序列分布,利用差示扫描量热分析(DSC)、热失重分析研究了共聚酯热性能、结晶动力学以及热稳定性。研究表明,投入体系的聚醚基本都进入了聚合物分子链;PTMG含量增加,聚合反应动力黏度增长变缓,共聚酯玻璃化转变温度(Tg)、结晶温度(Tc)、熔点(Tm)均明显降低,熔融结晶温度(Tmc)先上升后下降,试验制备的共聚酯较常规PET结晶速率更快。在氮气氛围中,共聚酯的热降解为一阶反应,PTMG含量增加,共聚酯热稳定性明显降低。 相似文献
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本文以对苯二甲酸(PTA)、乙二醇(EG)为主要原料,添加第三单体羟乙基化双酚A(BPE)经过直接熔融缩聚法合成了一系列不同BPE含量的共聚酯,研究分析了共聚酯的常规性能,利用1H-NMR、差式扫描量热法(DSC)研究了共聚物的链结构及热性能。结果表明:所得共聚物无规度值均接近1,为无规共聚物。随着BPE含量的增加,共聚酯二甘醇(DEG)含量逐渐下降;玻璃化转变温度(Tg)略微下降,熔融温度(Tm)、热结晶温度(Tmc)逐渐下降,冷结晶温度(Tc)逐渐上升,这些表明共聚酯的规整性、结晶能力随BPE用量的增加而下降。 相似文献
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以精对苯二甲酸(PTA)、乙二醇(EG)、新戊二醇(NPG)和不同含量的1,4-丁二醇(BDO)为原料,采用直接酯化法合成了一系列改性共聚酯,通过熔融纺丝法制得共聚酯纤维,研究了共聚酯的化学结构、结晶结构、热性能以及共聚酯纤维的力学性能。结果表明:由核磁共振氢谱表征并确定了共聚酯的化学结构为目标产物;与PET相比,共聚酯的晶型结构没有发生改变,其结晶度随着BDO含量的增加有所下降;随着BDO含量的增加,共聚酯的玻璃化转变温度和熔点都呈现出逐渐下降的趋势,但是其热稳定性并没有明显的变化,起始热分解温度高于335℃;对于共聚酯纤维,随着NPG的加入和BDO含量的增加,共聚酯纤维的断裂强度变化不大,断裂伸长率逐渐增大,初始模量逐渐减小,柔软度逐渐增大。 相似文献
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以对苯二甲酸(PTA)、乙二醇(EG)、异山梨醇(ISB)为原料,通过直接熔融缩聚法合成聚(对苯二甲酸乙二醇酯-co-对苯二甲酸异山梨醇酯)(PEIT)共聚酯。利用差示扫描量热法(DSC)研究了共聚酯的结晶行为,采用Avrami方程分析了共聚酯的等温结晶动力学。结果表明,PEIT共聚酯结晶行为受共聚组成和结晶温度影响。随着ISB用量的增加或结晶温度的降低,共聚酯半结晶周期t1/2增加、结晶速率变慢;ISB摩尔分数超过20%,共聚酯无法结晶。 相似文献
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以对苯二甲酸、乙二醇为主要原料,添加共聚单体新戊二醇(NPG)、5-叔丁基间苯二甲酸(tBI),通过熔融缩聚合成了一系列不同组成比例的共聚酯,分析了共聚酯的化学结构与组成、特性黏度、热性能、结晶性能和动态热力学性能。结果表明:随着tBI和NPG含量的增加,共聚酯的熔点降低,结晶能力逐渐减弱;当tBI和NPG物质的量分数总和达到13%及以上时,共聚酯为完全无定形态;tBI单元的加入使共聚酯的玻璃化转变温度升高,弥补了PENT共聚酯玻璃化转变温度低于PET的缺点;共聚酯的初始分解温度高于PET,初始储能模量大于PET,而随着测试温度的升高,共聚酯的柔韧性大于PET材料。 相似文献
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The objective of this study is to use the copolymerization method to improve the thermal shrinkage property of poly(ethylene terephthalate) (PET), so that the resultant copolyester can be used for the application of thermal shrinkage packing materials. The poly(ethylene isophthalate terephthalate) (PEIT) copolyester films were prepared and studied. The thermal shrinkage rate of PET films and the thermal shrinkage rate of the copolyester films were measured by using a thermomechanical analyzer (TMA). The thermal shrinkage of copolyester was found to be dependent on such factors as composition, molecular weight, and draw temperature. The highest thermal shrinkage was obtained when the copolymer contained 40 mol % of ethylene isophthalate. Its shrinkage ratio and shrinkage rate were consistently 1.3 and 2.4 times those of PET. The increase of molecular weight and decrease of drawing temperature resulted in the increase of the thermal shrinkage. The best drawing temperature range was between glass transition temperature and soft temperature of the copolymer. The relationship of shrinkage rate and temperature indicate that the shrinkage mechanism of the copolyester belongs to two-step thermal shrinkage. 相似文献
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Thermotropic liquid crystalline polymers (TLCP), 4‐hydroxybenzoic acid (HBA)/6‐hydroxyl‐2‐naphthoic acid (HNA) copolyester, and HNA/hydroxylbenzoic acid (HAA)/terephthalic acid (TA) copolyester reinforced by carbon nanotube (CNT) were prepared by melt compounding using Hakke internal mixer. The thermal behavior and degradation of CNT reinforced HBA/HNA copolyester and HNA/HAA/TA copolyester have been investigated by dynamic thermogravimetric analysis under nitrogen atmosphere in the temperature range 30 to 800°C to study the effect of CNT on the thermal decomposition behavior of the TLCP/CNT nanocomposites. The thermal decomposition temperature at the maximum rate, residual yield, integral procedural decomposition temperature, and activation energy for thermal decomposition was studied to investigate thermal stability of TLCP/CNT nanocomposites. The thermal stability of CNT reinforced HBA/HNA copolyester was increased by addition of a very small quantity of CNT and the residual weight was 42.4% and increased until 50.8% as increasing CNT contents. However, the thermal stability of CNT reinforced HNA/HAA/TA copolyester was decreased initially when a very small quantity of CNT added. The residual weight was decreased from 50.4% to 45.1%. After addition of CNTs in the TLCP matrix, the thermal stability of CNT reinforced HNA/HAA/TA copolyester increased as increasing content of CNT and the residual weight was increased until 53% as increasing CNT contents. The activation energy was calculated by multiple heating rate equations such as Friedman, Flynn‐Wall‐Ozawa, Kissinger, and Kim‐Park methods to confirm the effect of CNT in two different TLCP matrices. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
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Summary The thermal property and the miscibility of polycarbonate (PC)/copolyester blends were investigated. For the study, different copolyesters were synthesized from terephthalic acid (TPA) and various mixtures of ethylene glycol (EG) and cyclohexane dimethanol (CHDM). Various blends of PC and copolyester were prepared by melt mixing and thermal properties of the blends were studied employing differential scanning calorimeter. It was found that the blends of the PC and the copolyesters were partially miscible when the glycol in the copolyester was composed of 10, 20, or 30 mole % CHDM. However, the blends of the PC and the copolyesters were miscible in all proportions when the glycol in the copolyester was composed of 50 or 70 mole % CHDM. Miscibilities of the PC/copolyester blends depending on the composition of the copolyester are discussed based on the thermal properties of the blends. 相似文献
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Junming Dai Guang Li Shenglin Yang Jianming Jiang 《Polymer Engineering and Science》2012,52(7):1509-1515
A series of poly(ethylene terephthalate‐co‐4,4′‐bibenzoate)s (PETBBs) were prepared via direct esterification from the monomers of terephthalic acid (TPA), 4,4′‐biphenyl dicarboxylic acid (BPDA), and ethylene glycol (EG) with different molar ratios. The chemical compositions of the obtained PETBBs, investigated by H1‐NMR, were identical with the feed ratio, and the high molecular weights of PETBBs were confirmed by GPC analysis. The glass transition, crystallization, and melting behavior of them were measured by DSC; the results indicated that, in the range of 5–25 mol% of BPDA addition, the glass transition temperature (Tg) increased almost linearly and the melting temperature (Tm) decreased with increasing content of BPDA unit. As expected, the crystallization of PETBB became difficult with increasing introduction of BPDA, explained by higher crystallization temperature and smaller crystallization enthalpy from the glassy state. This decrease of crystallization rate may be beneficial to film processing. Moreover, owing to the introduction of rigid‐rod BPDA unit, the initial and maximum thermal‐oxidative decomposition temperatures were enhanced. The kinetic analysis of the thermal‐oxidative degradation indicated that the apparent activation energies of degradation for these PETBBs became higher than that of PET. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers 相似文献
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使用聚对苯二甲酸乙二酯(PET)-聚萘二甲酸乙二酯(PEN)无规共聚酯作增容剂,通过双螺杆挤出机熔融共混,制备了不同PET-PEN共聚酯用量的PET/PEN共混物,采用差示扫描量热分析、热重分析、热变形温度测试以及力学实验等方法,研究了该共混物的相容性及其它性能。结果表明,PET-PEN共聚酯对PET/PEN共混物具有明显的增容作用,能有效提高PET/PEN共混物的热稳定性,其用量越高,热稳定性提高越明显,当PET-PEN共聚酯用量为15质量份时,起始失重温度提高了20.3℃。PET-PEN共聚酯增容剂能提高PET/PEN共混物的维卡软化温度、拉伸和弯曲性能以及冲击性能,当PET-PEN共聚酯用量为5质量份时,增容改性的综合效果最好。 相似文献
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The phase behavior of polyarylate blends with a copolyester based on poly(1,4-cyclohexanedimethylene/ethylene terephthalate) was studied by differential scanning calorimetry and dynamic mechanical analysis. A single glass-transition temperature was observed over the entire composition range. Up to 30% weight polyarylate, the copolyester crystallized readily and its melting point did not change with blend composition. This indicates that transesterification, if it occurred, was negligible. The thermal and dynamic results also suggest a weak polymer-polymer interaction in this system. 相似文献