PBT共混改性研究最新进展

综述了最近几年国内外聚对苯二甲酸丁二醇酯(PBT)共混改性的研究进展,分类介绍PBT/聚烯烃、PBT/同系聚酯、PBT/液晶、PBT/弹性体、PBT/聚碳酸酯等不同共混体系,讨论了各体系中的相行为、相容性、热稳定性、力学性能等,并对该类共混物的发展趋势作了简要的分析。     

玻璃纤维增强PBT/PET共混物性能研究

采用双螺杆熔融挤出的方法制备玻璃纤维增强聚对苯二甲酸丁二酯(PBT)/聚对苯二甲酸乙二酯(PET)共混物。研究了PBT与PET不同比例对PBT/PET共混物性能的影响。在此基础上,研究了成核剂及不同种类的增韧剂对共混物性能的影响。结果表明,成核剂对提高共混物的相容性及热变形温度有重要作用,乙烯–甲基丙烯酸甲酯–丙烯酸缩水甘油酯三元共聚物型增韧剂(AX8900)质量分数为0.5%时,不影响共混物的耐热性及拉伸和弯曲强度,而且可以大大提高PBT/PET共混物的冲击强度。     

PTMEG共混改性PBT纤维的制备及其性能研究

以聚对苯二甲酸丁二醇酯-聚四亚甲基醚二醇(PBT-PTMEG)为改性剂,与聚对苯二甲酸丁二醇酯(PBT)进行共混纺丝,通过控制PBT-PTMEG添加量制备不同PTMEG含量的PTMEG/PBT共混纤维,探讨了PTMEG含量对纤维柔软性及其他性能的影响。结果表明:在共混纺丝过程中,PTMEG作为改性组分与PBT相容性良好,PTMEG质量分数为6%时可纺性好,继续增加至8%时可纺性变差;随着PTMEG含量的增加,PTMEG/PBT共混纤维的初始模量显著降低,断裂强度略有降低,断裂伸长率、断裂比功均逐渐提高,吸湿性及染色性能也得到改善;当PTMEG质量分数为6%、拉伸倍数为2.8时,PTMEG/PBT共混纤维的断裂比功最高达0.98 cN/dtex,初始模量也较低为21.8 cN/dtex,纤维的柔软性得到了明显提升,综合性能最好。     

ABS在聚合物共混改性中的研究进展

从聚合物共混改性原理的角度介绍PVC／ABS、PBT／ABS、PA／ABS三种重要的共混物。分析了ABS用量和加工工艺对共混物性能的影响，讨论了ABS共混物的增容改性技术。展望了ABS共混物的前景，并强调了研究过程中应注意的问题。     

PET/PBT扩链反应共混物的结晶熔融行为

用差示扫描量热法（ＤＳＣ）考察了添加扩链剂进行反应性共混后ＰＥＴ／ＰＢＴ的结晶熔融行为。共混体系的特性粘数随反应时间的增加先升后降,冷结晶温度随时间的增加逐渐升高,熔体结晶温度和熔点随之下降     

超韧PBT/PC共混物的研制

研究了3种增韧剂SWR-6B、AX8900和EXL-2691A对PBT/PC(80/20)共混物力学性能和耐热性的影响,并用扫描电子显微镜对PBT/PC共混物的微观形态结构进行了分析。结果表明,随着增韧剂用量的增加,PBT/PC共混物的缺口冲击强度不断提高,当3种增韧剂各自的用量增加到20份时,PBT/PC共混物的缺口冲击强度均达到600 J/m以上,约为未加入增韧剂时的10倍;当增韧剂的用量增加到30份时,PBT/PC共混物的缺口冲击强度达到900 J/m以上,同时共混物的拉伸强度和弯曲强度降低,而维卡软化温度仍高于200℃。     

PBT／ABS共混体系研究进展

选用适当的ABS对PBT进行改性,不加增容剂也能得到性能较好的共混物,但该共混物的性能对加工条件依赖程度较大,且加工窗口较窄,用含环氧官能团的一类聚合物对PBT／ABS共混体系进行反应增容后的有效地改善PBT的性能,使共混体系相分散好,共混物的形态结构稳定,加工窗口变宽,有利于得到性能稳定的共混物。     

PTT/PBT共混纤维的性能研究

利用聚对苯二甲酸-1,3-丙二酯(PTT)和聚对苯二甲酸丁二酯(PBT)良好的相容性,开发了PTT/ PBT共混纤维。通过对共混纤维的力学、回弹及染色等性能测试发现,PTT组分的存在明显改善了共混纤维的拉伸性能,而共混纤维的强度相对纯组分纤维略差;当PTT质量分数达到50%后,共混纤维的回弹性优于纯PBT纤维,且在相同拉伸倍数下,PTT的存在降低了共混纤维的沸水收缩率;共混纤维在常压下用分散蓝染色的上染率比纯组分纤维高,当PTT/PBT质量比为50/50时,上染率最高。     

玻璃纤维增强PBT/PC共混体系的研究

用双螺杆挤出机制备了不同组成的玻璃纤维增强聚对苯二甲酸丁二酯(PBT)／聚碳酸酯(PC)共混体系,研究了抗冲改性剂及酯交换抑制剂对共混体系力学性能的影响,并用扫描电子显微镜观察了不同共混体系的形态结构。结果表明,抗冲改性剂使共混体系冲击强度提高的同时,降低了共混体系的拉伸强度、弯曲强度及弯曲弹性模量;酯交换抑制剂的加入,降低了共混体系的力学性能,适当的酯交换反应有利于共混体系力学性能的提高;在该体系中PBT与PC相容性较好。     

PET/PBT共混过程中酯交换反应的~(13)CNMR研究

用13C NM R 考察了添加扩链剂进行反应性共混后PET/PBT 的结构变化。在共混初期,检测不到嵌段共聚物的存在,可能与其含量极少有关。随着共混时间的增加,开始出现酯交换反应,且酯交换度随共混时间和温度而增加。扩链剂的加入能促进酯交换反应,但扩链剂的用量对酯交换的影响并不大     

纳米粒子填充改性聚对苯二甲酸丁二醇酯

讨论了纳米粒子填充改性聚对苯二甲酸丁二醇酯（PBT）的研究进展，分别采用插层聚合和熔体聚合的方法制得PBT／纳米复合材料，讨论了结构和性能的关系。     

Novel poly(butylene terephthalate)/poly(vinyl butyral) blends prepared by in situ polymerization of cyclic poly(butylene terephthalate) oligomers

Blends of in situ polymerized PBT from cyclic oligomers (c-PBT) and PVB were prepared with varying compositions and compared with mechanical blends of conventional PBT and PVB. The materials were characterized by a variety of techniques including DSC, DMTA, DETA, FTIR, NMR and GPC. It was found that the in situ prepared blend of c-PBT/PVB has one glass transition temperature and shows evidence of miscibility. In contrast, the conventional blend of PBT/PVB shows incompatibility after blending. The cause of miscibility in the in situ prepared PBT/PVB blends is thought to be the formation of a graft copolymer. These results show that there are unique possibilities for in situ processing by combining polymerization of cyclic polyester oligomers with blending.     

Characterization and biodegradability of poly(butylene adipate‐co‐succinate)/poly(butylene terephthalate) copolyester

Characterization of poly(butylene adipate‐co‐succinate) (PBAS)/poly(butylene terephthalate) (PBT) copolyesters resulting from the intermolecular ester‐exchange reaction between molten PBAS and PBT have been analyzed using ¹H‐NMR spectroscopy, differential scanning calorimetry, wide‐angle X‐ray diffraction, and total organic carbon lab analyzer. Using the assignment of proton resonance due to homogeneous and heterogeneous dyads, the average block lengths were investigated over the entire range of copolymer composition. A decrease in melting temperature was observed with the increase of a terephthalate unit in the composition. The result of X‐ray diffraction curve matches well with that of average block length and thermal property. When a rich component is crystallized, the poor component is excluded completely in a crystal formation. The biodegradability in copolyesters also depended on the terephthalate unit in the composition and average block length of the aromatic unit. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 593–608, 1999     

Flame retardancy of poly(butylene terephthalate) blended with phosphorous compounds

The thermal degradation and flame retardancy of poly(butylene terephthalate) (PBT) were studied with a focus on the effect of phosphorous compounds. Thermogravimetric analysis, pyrolysis/gas chromatography/mass spectrometry (Py/GC/MS), and elemental analysis were used to analyze the flame retardancy, which were observed by an Underwriters Laboratory UL‐94 test and a cone calorimeter. The 50% degradation temperatures of PBT blends with phosphorous compounds were the same as that of neat PBT. Six scission products were assigned by Py/GC/MS. The burning times of the UL test of several PBT blends were much shorter than that of neat PBT. The relation between flame retardancy and thermal degradation was analyzed with respect to the results of the scission products and the char in burned polymers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2326–2333, 2004     

Toughening of poly(butylene terephthalate) with epoxy-functionalized acrylonitrile-butadiene-styrene

Glycidyl methacrylate (GMA) functionalized acrylonitrile-butadiene-styrene (ABS) copolymers have been prepared via an emulsion polymerization process. These functionalized ABS copolymers (ABS-g-GMA) were blended with poly(butylene terephthalate) (PBT). DMA result showed PBT was partially miscible with ABS and ABS-g-GMA, and DSC test further identified the introduction of GMA improved miscibility between PBT and ABS. Scanning electron microscopy (SEM) displayed a very good dispersion of ABS-g-GMA particles in the PBT matrix compared with the PBT/ABS blend when the content of GMA in PBT/ABS-g-GMA blends was relatively low (<8 wt% in ABS-g-GMA). The improvement of the disperse phase morphology was due to interfacial reactions between PBT chains end and epoxy groups of GMA, resulting in the formation of PBT-co-ABS copolymer. However, a coarse, non-spherical phase morphology was obtained when the disperse phase contained a high GMA content (≥8 wt%) because of cross-linking reaction between the functional groups of PBT and GMA. Rheological measurements further identified the reactions between PBT and GMA. Mechanical tests showed the presence of only a small amount of GMA (1 wt%) within the disperse phase was sufficient to induce a pronounced improvement of the impact and tensile properties of PBT blends. SEM results showed shear yielding of PBT matrix and cavitation of rubber particles were the major toughening mechanisms.     

Poly(butylene terephthalate)/poly(ethylene glycol) blends with compatibilizers

Polymer blend systems offer a versatile approach for tailoring the properties of polymer materials for specific applications. In this study, we investigated the compatibility of polybutylene terephthalate (PBT) and poly(ethylene glycol) (PEG) blends processed using a twin-screw extruder, with the aim of enhancing their compatibility. Phthalic anhydride (PAn) and phthalic acid (PAc) were used as potential compatibilizers at different concentrations to improve interfacial interactions between PBT and PEG. Blend morphologies were characterized using scanning electron microscopy, which revealed improved interfacial compatibility and reduced phase separation with the incorporation of small amounts of PAn and PAc. Differential scanning calorimetry analysis indicated changes in the melting temperature (T_m) and glass transition temperature (T_g) of the blends owing to the compatibilizing effects of PAn and PAc. Dynamic mechanical analysis further corroborated the influence of the compatibilizers on the T_g and viscoelastic behavior. Thermogravimetric analysis demonstrated enhanced thermal stability with the addition of either PAn or PAc. Rheological measurements indicated an increase in complex viscosity with increasing compatibilizer content, indicating improved compatibility. The degradation point (T_d) of PBT/PEG blend increased from 158 to 200 and 319°C with the incorporation of 5 phr PAn and 2 phr PAc, respectively. Mechanical properties, including tensile strength, Young's modulus, and Izod impact strength, were evaluated. For instance, the tensile strength of PBT/PEG blend was enhanced from 43.5 to 48.7 and 49.7 MPa by incorporating 5 phr PAn and 2 phr PAc, respectively. However, the impact strength of PBT/PEG blend increased from 3.0 to 4.3 and 4.2 kJ/m² with the addition of 1 phr PAn and 1 phr PAc, respectively. The findings demonstrated that adding 5 phr PAn or 2 phr PAc to the PBT/PEG blends was advantageous, achieving a harmony of performance benefits and compromises. Rheological observations contributed significantly to the mechanical and thermal properties. Overall, the study highlights the significance of utilizing PAn and PAc as effective compatibilizers for enhancing the properties of PBT/PEG blends, making them potential candidates for various applications.     

Morphological analysis of poly(butylene terephthalate) spherulites during fusion

Summary A detailed morphological analysis of the melting process of poly(butylene terephthalate) (PBT) is presented. Investigations were conducted by polarizing optical microscopy, coupling the measurement of depolarized light intensity with examination of morphology of PBT spherulites during their fusion. These analyses allowed to prove that the spherulitic superstructure of PBT developed upon isothermal crystallization from the melt does not vary with temperature until complete melting takes place, despite the large reorganization involved in the fusion process. It is thus shown that the double melting behavior commonly observed in PBT does not arise from the presence of various spherulitic morphologies with different thermal stabilities, and the structural changes caused by the reorganization processes do not involve variations in the spherulitic morphology. The recrystallization of PBT above the apparent melting point was also analyzed, and the role of memory effects of crystalline precursors remaining in the melt was discussed.     

New catalyst for the synthesis of poly(butylene terephthalate) with high thermo‐oxidative stability

In this paper we report the employment of Ti(acac)₂(O‐iPr)₂ (titanium bisacetylacetonate diisopropylate) as a novel catalyst for the synthesis of poly(butylene terephthalate) (PBT). Large scale synthesis of several polymers with the new catalytic system and with the standard catalyst Ti(O‐nBu)₄ (titanium tetra‐n‐butylate) have been performed in a 20 L pilot plant. In the optimized reaction conditions, Ti(acac)₂(O‐iPr)₂ has shown significantly higher activity than standard catalyst, Ti(O‐nBu)_4. Furthermore, a stabilized PBT has been synthesized in the presence of Ti(O‐nBu)₄ as catalyst with the addition of the stabilizer U626. Then, the stability of the synthesized polymers toward thermo‐oxidation has been tested in a forced circulating air oven. The polymers obtained in the presence of Ti(acac)₂(O‐iPr)₂ system showed higher stability towards thermo‐oxidation than stabilized and not stabilized PBT, synthesized in the presence of Ti(O‐nBu)₄. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

聚对苯二甲酸丁二醇酯/黏土纳米复合材料的研究进展

综述了聚对苯二甲酸丁二醇酯/黏土纳米复合材料研究的最新进展;从黏土表面改性剂的种类、黏土含量及其近、远程结构等方面总结了影响复合体系形态、黏弹特性、结晶行为的控制因素;探讨并评述了复合体系内部基体与黏土的多层次结构与其结晶、流变行为间的关系。