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首页> 外文学位 >In-situ ultrasonic compatibilization of binary blends of flexible chain polyesters and aromatic liquid crystalline polymers.
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In-situ ultrasonic compatibilization of binary blends of flexible chain polyesters and aromatic liquid crystalline polymers.

机译：柔性链聚酯和芳族液晶聚合物的二元共混物的原位超声增容。

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摘要

The objective of this research was to improve the properties of immiscible polymer blends by developing a new ultrasonic extrusion process. The ability of ultrasonic treatment to induce recombination reactions in polymer blends was anticipated to result in fast in-situ compatibilization of immiscible blends. In order to test this hypothesis, a new ultrasonic extruder operating at a frequency of 20 kHz at amplitudes of 5, 7.5, and 10 mum was developed. Polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and wholly aromatic liquid crystalline copolyesters (LCPs) were selected to illustrate the effect of ultrasonic treatment on copolymerization of components through transesterification reactions in blends. The LCPs studied were a copolymer of hydroxybenzoic and hydroxynaphthoic acid (LCP1) and a copolymer of dioxydiphenyl, terephthalic and isophthalic acid (LCP2). PET/PEN, PET/LCP1, PEN/LCP1, and LCP1/LCP2 blends and their components were subsequently injection molded and spun into fibers.;PET underwent homopolymerization and degradation, respectively, at ultrasonic amplitudes of 7.5 mum and 10 mum, while PEN underwent degradation at all amplitudes. MALDI-TOF mass spectroscopy revealed greater amounts of hydroxyl and carboxyl terminated oligomers in ultrasonically treated PET and PEN. Transesterification (copolymer formation) was observed in PET/PEN blends, which was enhanced with ultrasonic treatment, as indicated by 1H NMR and MALDI-TOF. Oxygen permeability of compression molded films of untreated and ultrasonically treated PET/PEN blends followed theoretical predictions for miscible blends.;Ultrasonic treatment of LCP1 at amplitudes of 7.5 and 10 mum led to improved mechanical properties of its injection moldings. On the other hand, LCP2 underwent degradation with treatment, leading to a reduction of mechanical properties of LCP2 and LCP1/LCP2 blends. However, due to enhanced fibrillation, these blends retained synergism such that moldings exhibited mechanical properties above the rule of mixtures. At the same time, mechanical properties of spun fibers followed the rule of mixtures.;Ultrasonically induced copolymer formation, further enhanced with higher residence time in the ultrasonic zone, was also detected by MALDI-TOF in PET/LCP1 and PEN/LCP1 blends. LCP fibrillation in moldings and spun fibers of these blends was controlled by the viscosity ratio of matrix polymer to LCP1. Homopolymerization of PET in PET/LCP1 blends, along with copolymer formation at 7.5 mum, improved fibrillation of LCP1 phase and interfacial adhesion. On the other hand, PET degradation and copolymer formation at 10 mum led to a competition between the reduction of LCP1 fibrillation and the improvement of interfacial adhesion. This competition dictated the mechanical properties of blends. Similar effects were observed in PEN/LCP1 blends. The addition of transesterification catalysts (antimony trioxide and tetrabutyl orthotitanate) to PEN/LCP1 blends induced degradation of PEN without and with ultrasonic treatment, leading to reduced LCP1 fibrillation, and therefore poor mechanical properties. However, treatment of PEN/LCP1 blends at an amplitude of 10 mum in the presence of catalysts induced greater copolymerization and higher mechanical properties.;Observations were supported by rheological, thermal, and morphological analysis.
机译：这项研究的目的是通过开发一种新的超声挤压工艺来改善不混溶的聚合物共混物的性能。预期超声处理在聚合物共混物中引起重组反应的能力将导致不混溶共混物的快速原位相容性。为了检验这一假设，开发了一种新的超声挤出机，其工作频率为20 kHz，振幅为5、7.5和10毫米。选择聚对苯二甲酸乙二酯（PET），聚萘二甲酸乙二醇酯（PEN）和全芳族液晶共聚酯（LCP）来说明超声处理对共混物中酯交换反应对组分共聚的影响。所研究的LCP是羟基苯甲酸和羟基萘甲酸的共聚物（LCP1）以及二氧基二苯基，对苯二甲酸和间苯二甲酸的共聚物（LCP2）。随后将PET / PEN，PET / LCP1，PEN / LCP1和LCP1 / LCP2共混物及其组分注射成型并纺成纤维; PET分别在7.5μm和10μm的超声振幅下均聚和降解，而PEN经历了所有幅度的退化。 MALDI-TOF质谱显示在超声处理过的PET和PEN中，羟基和羧基封端的低聚物数量更多。如1H NMR和MALDI-TOF所示，在PET / PEN共混物中观察到酯交换反应（形成共聚物），并通过超声处理增强了酯交换反应。未经处理和超声处理过的PET / PEN共混物的压塑薄膜的透氧性遵循理论上可混溶共混物的预测;超声处理LCP1的振幅为7.5和10μm可改善其注塑成型品的机械性能。另一方面，LCP2经过处理会降解，从而导致LCP2和LCP1 / LCP2共混物的机械性能下降。然而，由于增强的原纤化作用，这些共混物保持了协同作用，使得模制品显示出高于混合物规则的机械性能。同时，纺丝纤维的机械性能遵循混合物的规律。MALDI-TOF在PET / LCP1和PEN / LCP1共混物中还检测到超声诱导的共聚物形成，并随着在超声区域中停留时间的增加而进一步增强。这些共混物在模制品和短纤中的LCP原纤化是通过基体聚合物与LCP1的粘度比来控制的。 PET / PET / LCP1共混物中的PET均聚，以及在7.5 mm处形成共聚物，改善了LCP1相的原纤化和界面粘合性。另一方面，PET降解和10毫米的共聚物形成导致LCP1原纤化减少与界面粘合性改善之间的竞争。竞争决定了共混物的机械性能。在PEN / LCP1混合物中观察到了类似的效果。将酯交换反应催化剂（三氧化二锑和原钛酸四丁酯）添加到PEN / LCP1混合物中，可在不使用超声处理和进行超声处理的情况下诱导PEN降解，从而导致LCP1原纤化减少，因​​此机械性能较差。然而，在催化剂存在下，PEN / LCP1共混物在10微米振幅下的处理引起更大的共聚和更高的机械性能。流变，热和形态分析支持了观察。

著录项

  • 作者

    Gunes, Kaan.;

  • 作者单位

    The University of Akron.;

  • 授予单位 The University of Akron.;
  • 学科 Chemistry Polymer.;Engineering Materials Science.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 469 p.
  • 总页数 469
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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