磷系阻燃共聚酯流变性能探讨

采用日本岛津KOKA302型毛细管流变仪,对有光阻燃聚酯切片的流变性能进行了研究,并与普通有光聚酯切片的流变性能进行了比较。结果表明：阻燃聚酯熔体属非牛顿流体;与普通聚酯相比,阻燃聚酯熔体黏度偏低,对温度的敏感性相对较大,高磷含量阻燃聚酯对温度敏感性更大。流变性研究为磷系阻燃共聚酯切片的纺丝、成形、加工工艺条件的制订提供了依据。     

间苯二甲酸共聚酯的流变特性

对聚对苯二甲酸乙二醇酯（ＰＥＴ）中加入间苯二甲酸的无规共聚酯（Ａ２）的流变性能进行了研究。结果表明：Ａ２熔体是切力变稀流体;共聚酯大分子中第三组分的加入,使体系粘度降低,粘流活化能比ＰＥＴ高,表明共聚酯粘度对温度的敏感性较大;同一温度下,共聚酯的非牛顿指数比常规聚酯的高,说明共聚酯的流动偏离牛顿流体的程度小;共聚酯的弹性雷诺指数有所升高,但相对于常规聚酯的变化量不大。     

PETG熔体流变性能的研究

对PETG共聚酯熔体的流变性能进行研究,讨论了树脂的粘度、加工温度以及加工助剂的影响,比较了PETG与PET流变性能的不同。结果表明,PETG的熔体强度可以进行调节。     

阻燃共聚酯的流变性能

以对苯二甲酸、乙二醇和2-羧乙基苯基次膦酸为单体制备阻燃共聚酯,采用熔融指数仪和毛细管流变仪对试样的流变性能进行了研究。结果表明:阻燃共聚酯是典型的切力变稀非牛顿假塑性流体;其活化能随着剪切速率的增大而减小,熔体黏度对温度敏感程度较低;随着温度的提高,阻燃共聚酯的非牛顿指数升高,而随着剪切速率的增大,非牛顿指数减小;结构黏度指数随着温度升高而降低;混合制得的阻燃共聚酯与直接酯化缩聚制备的阻燃共聚酯的流变性能差异不大。     

热塑性淀粉/生物降解共聚酯共混物流变性能的研究

研究了热塑性淀粉(TPS)以及TPS/生物降解共聚酯共混物的流变行为,讨论了增翅剂用量、共聚酯用量和熔体温度对流变行为的影响.研究表明,TPS和TPS/生物降解共聚酯共混物熔体呈明显的非牛顿特征;增塑剂的使用可以大幅度改善淀粉的塑化行为,通过调节增塑剂用量,可以在一定范围内控制TPS的流变行为.对于共聚酯和TPS的共混体系而言,在共聚酯用量较低时,流动过程中TPS分子链受到较强剪切力作用而发生断链,共混物熔体表观黏度降低.在共聚酯用量较高时,共混物熔体黏度则表现出对温度有较大的敏感性.TPS的黏流活化能较小,TPS/生物降解共聚酯共混物的黏流活化能随共聚酯用量的增加迅速增大,且随剪切速率的增加迅速降低.     

PET-PBT共聚酯的流变性能研究

共聚酯的流变性能的研究表明:共聚酯的熔体是典型的切力变稀假塑性流体。共聚酯熔体粘度随ＰＢＴ链段的引入及含量的增加而下降,同时也随温度的升高而降低。第三组份的引入和分子量的提高也使共聚酯的熔体粘度呈下降趋势。共聚酯熔体的粘流活化能均低于常规ＰＥＴ,而其非牛顿指数ｎ值均高于常规ＰＥＴ,且随温度的升高及第三组份的引入而增大。     

NEP型超有光聚酯流变性能研究

通过毛细管流变仪研究了NEP型超有光聚酯的流变性能,并与普通超有光聚酯流变性能进行了比较。结果表明,NEP型聚酯与普通超有光聚酯熔体表现均为假塑性流体。NEP型聚酯的黏流活化能比普通超有光聚酯低,温度对NEP型聚酯熔体黏度影响较低,而对普通超有光聚酯的熔体黏度影响更为显著。在低剪切速率下,NEP型比普通超有光聚酯更接近牛顿流体。高剪切速率下,NEP型聚酯比普通超有光聚酯的非牛顿指数高,随温度升高,普通超有光聚酯的非牛顿指数增加幅度更大。     

多功能共聚酯流变性能的研究

利用 XLY- 流变仪研究了多功能共聚酯与 PET的流变性能。结果表明 ,多功能共聚酯的流动性好于 PET,其表观粘度对剪切速率的变化比 PET更敏感 ,对温度的依赖性不如 PET大 ,而 Ba SO4 对高聚物熔体起增粘作用。     

常压阳离子可染聚酯熔体的流变性能研究

应用高压毛细管流变仪测试了2种常压阳离子染料可染聚酯(ECDP-1,ECDP-2)熔体的流变性能并与常规聚酯(PET)熔体的流变性能进行对比.结果表明:ECDP-1,ECDP-2与PET熔体都属于假塑性非牛顿流体,黏度随剪切速率((γ))的增大而减小;ECDP-1,ECDP-2与PET熔体的非牛顿指数都随温度的升高而增...     

新戊二醇和聚乙二醇改性易染共聚酯的流变性能

利用双柱型毛细管流变仪对由新戊二醇(2,2-甲基-1,3-丙二醇,NPG)和聚乙二醇(PEG)共聚改性易染共聚酯的流变性能进行测试研究。试验结果表明:共聚酯熔体都是非牛顿假塑性流体,具有剪切变稀的特点;相较于易染共聚酯来说,改性易染共聚酯的黏流活化能较低,对温度不敏感,对剪切速率的变化更敏感,其流动性增强,可纺性得到了提升;改性易染共聚酯的非牛顿指数值随着温度的升高而上升,表明流动性能随着温度上升而增加。     

热致液晶共聚酯PET／60PHB的合成及性能研究

通过研究影响ＰＥＴ／６０ＰＨＢ对数比浓粘度的诸多因素，确定了缩聚反应的最佳工艺条件，并在该下合成了对数比浓粘度达０．７以上的ＰＥＴ／６０ＰＨＢ共聚酯，用ＮＭＲ，ＩＲ，ＰＯＭ，ＤＳＣ，ＷＡＸＤ和流变学等方法对其结构和液晶性进行了研究和分析，结果表明，合成的聚合物ＰＥＴ／６０ＰＨＢ（ＹＳＴＬ－１）确系ＰＥＴ与ＰＨＢ的无规共聚酯，属向列相热致液晶，加工试验表明，该共聚酯具有优良的加工流动性，其力学性能，     

氢氧化钠催化多聚甲醛与苯酚缩聚工艺对树脂性能的影响

采用氢氧化钠催化多聚甲醛与苯酚合成酚醛树脂。在氢氧化钠用量、水量恒定和加成工艺条件不变情况下,研究了缩聚温度、缩聚时间对产品黏度、固含量、拉伸强度及可发性的影响,并用红外光谱对产品进行表征。结果表明:与缩聚温度相比,产品的黏度对缩聚时间敏感;与缩聚时间相比,产品的固含量对缩聚温度敏感,产品的拉伸强度对缩聚温度敏感;产品黏度和固含量综合影响泡沫的质量;红外光谱表明产品的分子结构含有酚醛树脂的特征官能团。     

磷系阻燃改性共聚酯的热性能研究

选用主链含磷的阻燃剂2-羧乙基苯基次膦酸和侧链含磷的阻燃剂9,10-二氢-9-氧杂-10-[2,3-二(2-羟基乙氧基)羰基丙基]-10-磷杂菲-10-氧化物,在3 L聚合反应釜上分别合成了磷质量分数为0.6%的阻燃改性共聚酯。利用TGA、DSC对其热性能进行了分析,并对其切片干燥和熔融后的黏度降进行了测试。结果表明,随着反应型阻燃剂的添加,阻燃共聚酯的tg,tm下降,而Δt热和Δt冷则呈上升趋势,结晶能力下降;共聚酯的初始热分解温度有所下降,经切片干燥和熔融后的黏度降增大。     

AA/PTA单体比例对PBAT共聚酯性能的影响

以己二酸（AA）、对苯二甲酸（PTA）和1,4-丁二醇（BDO）为原料,钛酸四丁酯为催化剂,采用先酯化后缩聚的两步聚合法制备了一系列聚（己二酸/对苯二甲酸丁二醇）（PBAT）共聚酯。研究己二酸与对苯二甲酸不同摩尔比对合成共聚酯的结构、热性能和弹性性能的影响。FTIR和NMR测试结果表明本实验成功合成了PBAT共聚酯。GPC测试结果表明共聚酯的重均分子量（M_w）在41000~142000之间,测试结果与特性黏度具有一致性。DSC测试结果表明随己二酸含量的增加,共聚酯的熔融温度和结晶温度逐渐降低;WXRD测试结果表明随着己二酸含量的不断增加,共聚酯的晶型结构逐渐由PBA转变为PBT;DMA结果表明玻璃化转变温度（T_g）基本呈不断降低的趋势;TGA结果表明PBAT共聚酯的初始分解温度随对苯二甲酸含量的增加向高温区移动,而在高温段共聚酯的热稳定性接近。拉伸结果表明,AA/PTA比例的变化显著影响共聚酯的力学弹性,PBAT7：3具有最大的断裂伸长率,而PBAT3：7则表现为强而韧的拉伸特性。     

Synthesis and characterization of aromatic copolyesters containing siloxane linkages in the polymer backbone

A new series of aromatic copolyesters containing siloxane linkages were prepared by the melt polymerization of bisphenol A (BPA) with eugenol end‐capped siloxane (EuSi), diphenyl terephthalate (DPT), and diphenyl isophthalate (DPI) in varying ratio in the temperature range 220–290°C under reduced pressure in the presence of dibutyl tin dilaurate (DBTL) catalyst. The siloxane copolyesters prepared were characterized by FTIR, ¹H‐NMR spectroscopy, solution viscosity, thermogravimetric analysis, differential scanning calorimetry, and X‐ray diffraction. The effect of incorporation of eugenol end‐capped siloxane was studied on the properties of BPA/DPI/DPT copolyesters. The glass‐transition temperature of copolyester was decreased from 184 to 70°C by incorporation of 20% of eugenol end‐capped siloxane. All copolyesters were found to be soluble in commonly used aprotic polar solvents and had film‐forming properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3222–3228, 2006     

A flame-retardant-free and thermo-cross-linkable copolyester: Flame-retardant and anti-dripping mode of action

Flame-retardant-free and thermo-cross-linkable copolyesters have been synthesized, and their flame retardation and anti-dripping behavior as a consequence of cross-linking during combustion were investigated in detail. TG-DSC simultaneous thermal analysis, rheological analysis, and TGA established the extent and rate of the cross-linking reaction. The extent of cross-linking depends on the content of cross-linkable monomer, PEPE, and the higher the extent of the cross-linking, the better the flame retardance and anti-dripping performance of copolyesters. The large melt viscosity caused by cross-linked networks at high temperature played the most important role in anti-dripping of copolyesters. TG-FTIR results confirmed that the flame-retardant activity of copolyesters mainly took effect in the condensed phase, and XPS results indicated that the carbonization process was aromatization-dominant. SEM and Raman analysis suggested that the char layers were constituted mainly of polyaromatic species with small and uniform microstructures at the surface. Consequently, both the large melt viscosity and the formation of an especially compact char with fine microstructure resulting from cross-linking were considered as the key to the flame retardance and anti-dripping performance of the polymer when subjected to the flame.     

低熔点共聚酯的流变性研究

由对苯二甲酸(PTA)、间苯二甲酸(IPA)、丁二醇(BDO)共缩聚制备了低熔点共聚酯。采用Rosand RH7型毛细管流变仪对不同摩尔百分比组成的共聚酯的流变性进行了研究。结果显示:低熔点共聚酯是典型的假塑性流体,随着温度升高,剪切黏度下降,非牛顿指数增大;随着剪切速率的增大,低熔点共聚酯黏流活化能降低。比较了两种组成的低熔点共聚酯的流变性,发现随着第三单体IPA的增加,低熔点共聚酯的剪切黏度降低,非牛顿指数减小。分析了第三单体对低熔点共聚酯流变行为的影响。     

Fast crystallization of liquid crystalline copolyesters based on poly(ethylene terephthalate)

Crystallization of a series of liquid crystalline copolyesters prepared from p‐hydroxybenzoic acid (HBA), hydroquinone (HQ), terephthalic acid (TA), and poly(ethylene terephthalate) (PET) was investigated by using differential scanning calorimetry (DSC). It was found that these copolyesters are more crystalline than copolyesters prepared from PET and HBA. Insertion of HQ–TA disrupts longer rigid‐rod sequences formed by HBA and thus enhances molecular motion and increases the crystallization rate. The effects of additives on the crystallization of the copolyesters were also studied. Sodium benzoate (SB) and sodium acetate (SA) increase the crystallization rate of the copolyesters at low temperature, but not at high temperature. It is most likely that liquid crystalline copolyesters do not need nucleating agents, and small aggregates of local‐oriented rodlike segments in nematic phase could act as primary nuclei. Chain scission of the copolyesters caused by the reaction with the nucleating agents was proved by the determination of intrinsic viscosity and by the IR spectra. Diphenylketone (DPK) was shown to effectively promote molecular motion of chains, leading to an increase in the crystallization rate at low temperature, but it decreased the crystallization rate at high temperature. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 497–503, 2001     

PET/PHB液晶共聚酯的合成及液晶性能

将对羟基苯甲酸（ＰＨＢ）单元引入聚对苯二甲酸乙二酯（ＰＥＴ）中,合成液晶共聚酯,１步法工艺优于２步法。就１步法工艺研究缩聚温度、时间、催化剂用量及ＰＨＢ含量对ＰＥＴ／ＰＨＢ共聚酯对数比浓粘数的影响。用偏光显微镜研究结果表明,ＰＥＴ／ＰＨＢ共聚酯呈丝纹形结构,属向列型液晶。用差示扫描量热仪研究的结果也反映出向列型液晶的特征。     

Preparation and properties of copolyesters polymerized in a vented extruder

High molecular weight thermoplastic copolyesters from bisphenol A, neopentyl glycol, and terephthaloyl chloride have been prepared by a melt-polymerization technique carried out in a twin-screw, vacuum-vented extruder. Low molecular weight polymer, polymerized in a conventional melt reactor, was further polymerized to copolyesters with intrinsic viscosities, under the conditions investigated, of up to 0.76 dl/g. The optimum extruder reaction conditions with respect to temperature profile, vent configuration, and polymer throughput are described. A variety of properties for two representative copolyester compositions have been determined. Particular attention was given to melt viscosity and impact strength, two properties which depend markedly on whether the polymer is prepared by the subject melt process or, alternately, by a low temperature interfacial polycondensation. It is concluded, based on a study of deliberately branched, interfacially prepared copolyesters, that the property differences which depend on the polymerization method are attributable to the formation of branches in the copolyesters prepared by the high-temperature melt process.