原位缩聚合成含聚芳酰胺/酯的微相复合材料Ⅱ.基体聚合物溶剂对微相复合材料形态与性能的影响

通过研究对羟基苯甲酸(HB)在基体聚合物聚对苯二甲酸丁二醇酯-聚四亚甲基醚多嵌段共聚物(PBT-PTMG) 的溶液中原位缩聚制备微相复合材料过程中所用溶剂的影响,研究基体聚合物溶剂对微相复合材料形态与性能的影响。     

聚酯-聚醚嵌段聚合物取向材料的研究

本文是对硬链段聚对苯二甲酸乙二酯-软链段聚四亚甲基醚聚酯-聚醚嵌段共聚物的冷拉取问,并通过热定型而得到高强度、高模量的材料及其物理机械性能的研究。 实验部分 样品的制备 聚酯-聚醚嵌段聚合物按一般熔融缩聚法制得。硬链段聚酯重量含量40％,[η]=1.37,在英国1122 Instron     

玻璃纤维增强PCT/PBT合金性能研究

对不同配比玻璃纤维增强聚对苯二甲酸1,4-环己烷二甲醇酯(PCT)/聚对苯二甲酸丁二醇酯(PBT)合金的冷结晶性能,熔融结晶性能,流动性,耐热氧老化性能进行了研究。结果表明,在玻璃纤维增强PCT/PBT合金体系中,PBT的添加可显著降低PCT的冷结晶温度; PBT或PCT中任何一种组分的加入都会导致另一组分熔点的下降; PCT与PBT会发生一定程度的酯交换反应,形成部分共聚物,但共混体系两组分是分别结晶的,并不能形成共晶或混晶; PBT含量的提高会明显改善合金体系的流动性,但合金体系的初始反射率和长期耐热氧老化性能会下降。     

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。     

主链含硅的芳香嵌段共聚酯的制备

通过酯交换、熔融缩聚的方法将含硅耐热单元引入到聚对苯二甲酸丙二醇酯-聚四亚甲基醚二醇大分子链中,制备了一系列硅含量不同的嵌段共聚酯,并对其结构、特性黏数、熔融和结晶性能、热稳定性能以及燃烧后试样形态进行了表征和分析。结果表明:通过熔融缩聚可以合成含硅嵌段共聚酯;含适量硅组分的共聚酯具有良好的结晶性能,更高的热稳定性,有一定的阻燃性;随着主链中硅含量的增加,共聚酯的熔点降低,起始结晶温度和残炭量均升高,当硅油质量分数为7%时,冲击强度提高了2.5倍。     

可堆肥脂肪-芳香族共聚酯PBAT是什么

正PBAT是聚对苯二甲酸己二酸丁二醇酯的缩写,或称己二酸对苯二甲酸-丁二醇共聚酯。PBAT是一种生物可降解无规共聚物。其具体合成路线如下:己二酸与1,4-丁二醇聚合成聚己二酸丁二醇酯(+水);对苯二甲酸二甲酯与1,4-丁二醇反应生成聚对苯二甲酸二甲酸丁二醇酯(+甲醇);将聚对苯二甲酸二甲酸丁二醇酯加到聚己二酸丁二醇酯中,使用钛酸四丁酯作酯交换催化剂,得到两种预制聚合物的共聚物PBAT。     

车用高分子材料——PBT的增韧与改性

为满足车用高分子材料的应用需求,对聚对苯二甲酸丁二酯(PBT)的增韧改性展开研究,采用乙烯-乙酸乙烯酯共聚物对PBT进行增韧改性,引入增容剂苯乙烯-马来酸酐共聚物,并研究了共混物的性能。结果表明:乙烯-乙酸乙烯酯共聚物能够显著改善共混物的加工性能和力学性能,且适量增容剂的引入有效地提高了共混体系的相容性,当共混物中乙烯-乙酸乙烯酯共聚物质量分数为30%,苯乙烯-马来酸酐共聚物含量为0.5 phr时,力学性能和界面强度达到最优。     

PETG共混及复合材料的研究进展

以不同的物质为主线,综述了聚对苯二甲酸乙二酯-1,4-环己烷二甲酯(PETG)与聚碳酸酯、丙烯腈-丁二烯-苯乙烯共聚物、聚对苯二甲酸丁二醇酷、无机纳米及黏土(如纳米氧化锌、蒙脱土)、沙林树脂、聚乙醇酸、聚乳酸等各类物质共混改性及复合材料的研究进展.总结了PETG的各种复合材料需要考虑的综合问题及未来的发展趋势.     

PET/PEN/成核剂共混物的等温结晶动力学

采用差示扫描量热法,利用Avrami方程研究了聚对苯二甲酸乙二酯(PET)/聚2,6萘二甲酸乙二酯(PEN)/成核剂共混物的等温结晶动力学,并用Arrhenius方程计算了共混物的活化能。结果表明:结晶速率随结晶温度的升高而下降;Avrami方程能较好地描述PET/PEN/成核剂共混物的等温熔融结晶过程;加入成核剂对等温结晶有一定影响,4种试样的Avrami指数为2.5~2.7;共混物的活化能由大到小依次为PET/PEN,PET/PEN/1,3:2,4-二(亚苄基)-D-山梨醇,PET/PEN/Ca CO3,PET/PEN/苯甲酸钠。     

木质素与聚对苯二甲酸丁二酯的共混及相容性研究

利用微型双螺杆共混仪研究了木质素与聚对苯二甲酸丁二酯的共混过程。热力学分析和红外光谱分析表明:木质素与聚对苯二甲酸丁二酯共混体系有较好的相容性,主要原因是木质素与聚对苯二甲酸丁二酯间有强的氢键形成。     

PBT-PTMG嵌段共聚酯的研究

对以对苯二甲酸二甲酯、1,4-丁二醇和四氢呋喃聚醚二元醇为原料,钛酸四丁酯为催化剂制备PBT—PTMG嵌段共聚酯的工艺方法进行了研究。制备了软硬段比不同的PBT—PTMG嵌段共聚酯切片,并对其性能进行了表征。其结果显示,PBT—PTMG嵌段共聚酯的密度和硬度都随PBT含量的增大而增大,吸水率随聚醚含量增大而增大;调节PBT-PTMG嵌段共聚酯的组成可以得到具有不同力学性能的产物,且具有良好韧性。     

DBDPE/Sb2O3与Exolit^（TM）OP（1240）对弹性体PBT-PTMG性能的影响

以钛酸四丁酯为催化剂合成了热塑性聚醚酯弹性体PBT-PTMG,并研究了有卤阻燃体系十溴二苯乙烷/三氧化二锑（DBDPE/Sb2O3）和无卤的磷系阻燃剂Exolit TMOP1240对弹性体PBT-PTMG的力学性能、阻燃性能、热力学性能及其结晶等方面的影响。研究结果表明：添加阻燃剂可以显著提高PBT-PTMG的阻燃性能,使其垂直燃烧性能达到LU94V-0级;随着阻燃剂添加量增大,PBT-PTMG的力学性能降低,DBDPE/Sb2O3及Exolit TMOP1240的最佳添加量均为DMT质量的5%;添加阻燃剂会影响弹性体PBT-PTMG的结晶性能,使体系晶体形状和晶体数目发生改变;添加阻燃剂后,PBT-PTMG的热稳定性无明显变化。     

PET-PTMG聚醚酯熔融与结晶行为的研究

采用熔融缩聚法合成了一系列聚对苯二甲酸乙二醇酯(PET)-四氢呋喃聚醚(PTMG)聚醚酯，用DSC、偏光显微镜表征了材料的熔融与结晶性能，讨论了组成对聚醚酯的熔点、结晶温度、结晶度、结晶形态的影响。结果表明，PET—PTMG聚醚酯的熔点与组成的关系符合Baur公式；其结晶度随着聚醚含量的增加呈现先升高后下降的趋势；并为明显的结晶与非结晶的两相结构形态。     

Investigation on isothermal crystallization,melting behaviors,and spherulitic morphologies of multiblock copolymers containing poly(butylene succinate) and poly(1,2‐propylene succinate)

In this article, isothermal crystallization, melting behaviors, and spherulitic morphologies of high‐impact multiblock copolymers, comprising of PBS as hard segment and poly(1,2‐propylene succinate) (PPSu) as soft segment with hexamethylene diisocyanate as a chain extender, were investigated. The results from differential scanning calorimetry (DSC) suggest that the two segments of multiblock copolymers are miscible in amorphous region. The crystallization kinetics were analyzed by the Avrami equation. The effect of PBS segment length as well as the introduction of PPSu segment on the crystallization kinetics and melting bebaviors of block copolymers was studied. Both crystallization rate (G) and spherulitic growth rate (g) are markedly increased with the increase of PBS segment length or decreased with the incorporation of PPSu segment. All the multiblock copolymers show the multiple melting behaviors, whose position and area depend on PBS segment length and the presence of PPSu segment. The melting peaks shift to higher temperature region with increasing PBS segment length. Spherulitic morphologies of the multiblock copolymers after being isothermally crystallized were examined by polarized optical microscopy. It is the first time to investigate the effect of one segment length on crystallization bebavior of block copolymers based on a fixed weight ratio systematically. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Characterization and crystallization behavior of poly(ethylene‐co‐trimethylene terephthalate) copolymers

A series of poly(ethylene‐co‐trimethylene terephthalate) (PETT) copolymers were prepared by polycondensation. The synthesized PETT are block copolymers and the content of poly(trimethylene terephthalate) (PTT) units incorporated into the copolymers are always larger than that fed in the polymerization. The nonisothermal crystallization at the different cooling rates was studied by means of differential scanning calorimetry. The copolymers develop the crystallization later and show the lower melting temperature than the corresponding enriched homopolymers. The modified Avrami analysis fit well the nonisothermal crystallization of these polymers. The overall rate of crystallization of PTT is fastest and that of PET is slowest, whereas the copolymers are between them at the same cooling rate. The minor PET units incorporated into PTT polymer chains reduce the crystallization of PTT segments, but the present minor PTT units in the PET chains seem to accelerate the crystallization of PET segments. The Avrami exponent nvaries in the range of 3 – 4, indicating that the nonisothermal crystallization follows the homogeneous nucleation and two‐ to three‐dimensional growth mechanism. Wide angle X‐ray diffraction analysis explains that the PET and PTT units do not cocrystallize and it is considered as the enriched polymer segments to crystallize during crystallization. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Crystallization and morphology of starch-g-poly(1,4-dioxan-2-one) copolymers

The thermal transition, crystallization and spherulitic morphology of starch-g-poly(1,4-dioxan-2-one) copolymers were studied by means of differential scanning calorimetry (DSC) and polarized optical micrographs (PM). It is found that the graft structures of copolymers have obvious effects on the thermal and crystallization behaviors. Because there were more defect sites in the crystalline phase originating from the short grafted chains of poly(1,4-dioxan-2-one) (PPDO), the crystal structure of the copolymers was much less perfect than that of PPDO. PM revealed that the spherulitic morphology of the graft copolymers depended on graft structures and crystallization temperatures. From the single polarized micrograph of the graft copolymers it was observed clearly that the starch segments acted as nucleation sites. The Avrami equation was used to analyze the overall isothermal crystallization of the graft copolymers. Avrami exponents were almost constant at crystallization temperatures T_c ranging from 45 to 60 °C. Both the PM observation and the DSC investigation (crystallization rate constant, K values) indicated that the graft copolymers crystallize faster than pure PPDO, especially at higher crystallization temperatures.     

Kinetic studies of the crystallization of nylon-6 block copolymers

The crystallization kinetics of nylon-6 and nylon-6 block copolymers (NBC's) containing 1–3 mole % poly(ethylene oxide), PEO, were measured under isothermal and linear cooling conditions. The Avrami equation was used to fit the data. The range of the Avrami index n was from 1.5 to 2.2 for the system studied in the temperature range from 400–454 K. Maximum rate of crystallization was observed in the above temperature range. Nylon-6 block copolymers showed the maximum crystallization rate at a lower temperature than nylon-6. When the soft segment exceeded 3 mole %, no crystallization was observed. Cooling rate studies showed the same tendency. The crystallization rate behavior of nylon-6 block copolymers was similar to the pure nylon.     

不同拓扑结构PEG-PCL嵌段共聚物的结晶研究

合成了不同拓扑结构的聚乙二醇-聚己内酯(PEG-PCL)嵌段共聚物,共聚物结构分别为AB型线性两嵌段(diblock)、ABA型线性三嵌段(triblock)、AB_2型星形(star shape)嵌段共聚物。通过表征发现嵌段共聚物的分子量与设计的分子量接近,且相对分子量分布窄。通过XRD、DSC、热台偏光显微镜(HSPOM)研究了拓扑结构对共聚物结晶的影响。ABA聚合物中间的PEG亲水链受到两端PCL链段阻碍,其结晶衍射峰最弱。三者的等温结晶速率按AB、AB_2、ABA的速率递减,形成的球晶结构规整度则逐渐增加。     

丙烯/1-丁烯无规共聚物的非等温结晶行为研究

本体聚合方法合成了丙烯/1-丁烯无规共聚物,用DSC研究了丙烯/1-丁烯无规共聚物的非等温结晶动力学行为。结果表明：用Jeziorny方法处理丙烯/1-丁烯无规共聚物的非等温结晶行为存在一定的局限性;用莫志深方法处理丙烯/1-丁烯无规共聚物的非等温结晶行为可行, F(T)值随相对结晶度的升高而增大,在相对结晶度相同的条件下,随1-丁烯含量的增加,共聚物的结晶速率降低,结晶变得困难;对于同一种样品,在不同结晶度下α值几乎不变,近似为一常数,这说明表观Avrami指数n与Ozawa指数m之间存在一定的比例关系。     

Some properties of copolymers of vinylidene chloride with acrylates and methacrylates,Part 1

Copolymers of vinylidene chloride (VDC) and acrylates or methacrylates were investigated by calorimetric (DSC) and infrared spectroscopic methods to determine glass transition temperature and crystallization behavior. The final crystallinity of some annealed copolymers of VDC and methyl acrylate (MA) or methyl methacrylate (MMA) was studied by means of WAXS measurements. It was found that: (i) the glass transition temperature of copolymers of VDC and acrylates goes through a maximum as a function of the composition. The maximum shifts toward higher concentrations of VDC in the copolymer with increasing length of the ester group. (ii) However, for copolymers of VDC and methacrylates one observes a monotonic rise in the glass transition temperature with increasing concentration of the methacrylate, that can be described by the equation of Gordon and Taylor. (iii) For a given comonomer, the crystallization rate increases with increasing VDC content and, moreover, for a given VDC content it is slowest with methyl acrylate and fastest with ethylhexyl acrylate. Therefore, for a given crystallization rate, the copolymers of VDC and methyl acrylate contain the highest weight fraction of VDC. However, on a molar basis the differences are rather small. Analogous behavior is observed for the copolymers of VDC and acrylates or methacrylates. (iv) The final crystallinity of the annealed copolymers decreases linearly with decreasing VDC content. From this linear decrease, the limiting VDC concentration for zero crystallinity was extrapolated to about 75 mol-% VDC. These values are slightly lower than those estimated from infrared spectroscopy. Consequently, the final crystallinity of the copolymers studied is influenced by the VDC content rather than by the comonomer type. (v) The final crystallinity of the VDC homopolymer is determined as 57 ± 2 wt.-% in agreement with literature data. The crystallinity of the copolymers of VDC with different acrylates or methacrylates can then be estimated as a function of the composition.