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聚对苯二甲酸丙二醇酯论文：阳离子染料可染PTT共聚酯的合成及性能研究

【中文摘要】聚对苯二甲酸丙二醇酯(PTT)是一种新型聚酯材料,因其具有独特的性能而在服装、地毯、非织造布等领域具有广阔的应用前景,是当前国际上的热门高分子新材料之一。但由于PTT分子链中没有亲染料基团存在,导致传统的PTT纤维只能用分散染料进行染色,与阳离子染料染色相比,分散染料染色存在环保效果差、色谱不全、色泽不艳、设备投资成本高等缺点,在一定程度上限制了PTT在纤维上的应用。本文首先合成了间苯二甲酸丙二醇酯-5-磺酸钠(SIPP),然后引入SIPP为第三改性组分,以及两种不同第四组分聚1,6-己二酸-1,4-丁二醇酯(PBA)和聚乙二醇(PEG),通过直接酯化-缩聚工艺对PTT进行共聚改性,合成了一系列具有阳离子染料可染性能的共聚酯,并用核磁共振波谱仪(1H-NMR)分析了共聚酯的结构和组成,采用差示扫描量热仪(DSC)和热重分析仪(TGA)分析了共聚酯的基本热性能,利用双料管注塞式毛细管流变仪研究了共聚酯的流变性能,用DSC法分析了共聚酯的非等温结晶性能,为改性共聚酯的纺丝及其它后加工工艺提供基础数据。SIPP的合成工艺研究结果表明,钛酸四丁酯(Ti(OBu)4)对SIPP的合成反应有较好的催化活性,其用量为1000ppm较为合适,继续增加催化剂用量对反应速率影响不大,投料时1,3-PDO与SIPM的摩尔配比为10.14:1时最佳,在反应温度为173℃时,反应速率较快且产物色泽良好。采用直接酯化-缩聚工艺合成改性

共聚酯时,缩聚反应速率随着反应温度升高而加快,但温度过高会导致产物端羧基含量偏高,缩聚阶段温度控制在165～170℃。引入第三组分SIPP使缩聚反应速率加快,但缩聚反应后期熔体流动性变差,不利于产物特性粘度的提高,而引入第四组分PBA或PEG时,情况正好与此相反。常规PTT的玻璃化转变温度(Tg)、冷结晶温度(Tc)和熔点(Tm)分别为44.8℃、68.9℃和224.9℃,随着第三组分摩尔含量的增加,共聚酯的Tg先下降后升高,Tc逐渐升高,Tm逐渐降低;而随着第四组分PBA或PEG的质量百分含量的上升,共聚酯的Tg、Tc和Tm都逐渐降低。热重分析结果表明,所有改性共聚酯的热失重温度均在360℃以上,表明改性共聚酯的热稳定性能良好,都能满足进一步加工工艺的要求。流变分析结果显示,PTT及各共聚酯均属于非牛顿流体,非牛顿指数都小于1,在所考察的剪切速率范围内都表现出剪切变稀特性。第三组分SIPP的引入使共聚酯的流变性能变差,而引入第四组分PBA或PEG均能改善共聚酯的流变性能,有利于改性共聚酯的后续纺丝工艺。PTT及其改性共聚酯的非等温结晶动力学行为与Jeziorny方程相吻合,PTT的Avrami指数n在4.24～4.61之间,其结晶是按照均相成核并伴随三维球晶生长方式为主,引入第三组分或第四组分后,结晶的完善程度大大降低,结晶焓下降,共聚酯的Avrami指数n都在1.72～2.64之间,从而我们推测改性共聚酯结晶以异相成核方式为主。改性共聚酯的结晶活化能在13.27(kJ/mol·K)以上,明显要高于常规PTT的11.33 (kJ/mol·K),表明经过阳离子染料可染改性后的共聚酯的结晶能力变差,降温速率对改性共聚酯的结晶过程影响较大,

因此,在改性共聚酯的加工过程中对降温速率的控制极为重要。

【英文摘要】As a newly polyester, Poly(trimethylene terephthalate) (PTT) has wide application prospects in clothing, carpets, non-woven fabric etc for its unique properties. However, there is no group that can form chemical or lonic bonds with dyes in the molecular chain of PTT, resulting in the PTT fibers only can be dyed with disperse dyes. Compared with cationic dyes, the using of disperse dyes has many disadvantages, such as the poor environmental effects, the incomplete of chromatography, not brilliant of the color and the huge investment in equipment, to a certain extent, limited the application of PTT in the fiber industries. In this paper, SIPP was synthesised, and then SIPP was used as third monomer, PBA and PEG were employed as forth monomer to synthesis a series of modified PTT by polycondensation. The compositions and structures of copolyesters were determined by 1H-NMR. Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) were used to analyze the thermal properties of copolyesters. The rheological properties and the

non-isothermal crystallization behavior of copolyesters were detected by capillary rheometer and DSC, which could provide basic data for spinning or other processing of modified

copolyesters.The synthesis conditions of SIPP were optimized, results showed that Ti(OBu)4 was a efficient catalyst and the amount of it was appropriate to 1000ppm, continuing to increase the amount of catalyst has little effect on the reaction rate. The best feeding ratio of 1,3-PDO and SIPM is 10.14:1. The reaction rate was faster and the product has good color when the reaction temperature was 173℃. The polycondensation reaction rate was accelerated with the rising of the reaction temperature, but the concentration of the end carboxyl was too high at the higher reaction temperature, the reaction temperature was controlled between 165 to 170℃as better. The introduction of the third monomer SIPP accelerated the condensation reaction rate, but the flowability of the melt was getting worse and it was harmful to the improvement of the product intrinsic viscosity, while the introduction of the fourth monomer PBA or PEG could improve the flowability of the melt. The analysis of the thermal properties showed that the Tg, Tc and Tm of PTT were 44.8℃, 68.9℃and 224.9℃

correspondingly. With the increase of the third component, the Tg declined when a small amount of SIPP was introduced and then increased, Tc gradually increased, Tm decreased. With the increase of the PBA or PEG the Tg, Tc and Tm of the copolyesters

were all gradually reduced. TGA results suggested that all modified copolyesters’ thermo-gravimetric temperature were above 360℃, indicating that all modified copolyesters had good thermal stability, and could meet the requirements for further processing.Rheological behaviors analysis showed that PTT and its copolyesters were tipically non-Newton fluid, exhibiting shear thinning behavior in the investigated shear rate range, and the non-Newton index of them were all less than 1. The introduction of SIPP made the rheological properties of copolyesters become worse, while the introduction of PBA or PEG could improve the rheological properties of copolyesters, which was beneficial to the spinnability of copolyesters. The no-isothermal crystallization kinetics behaviors of PTT and its copolyesters were consistent with the Jeziorny equation, the Avrami exponent n of PTT were between 4.24 to 4.61, suggested a three-dimensional spherulite growth with homogenous nucleation mechanism. The Avrami exponent n of the modified copolyesters were approximately from 1.72 to 2.64, so we assumed that the crystallization mechanism of modified copolyesters was heterogeneous nucleation. The activation energy of modified copolyesters were abvious higher than PTT, suggesting that the crystallization rate of the copolyesters