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1.
监测了对-乙酰氧基苯甲酸与聚对苯二甲酸乙二醇酯(PET)共缩聚反应过程中HNMR图谱及特性粘度的变化,对乙酰氧基酯交换反应及乙酰脂肪酯的反应活性进行了研究,并研究了以低分子量PET或对苯二甲酸二乙二醇酯为原料时反应中醚键的形成及其进入共聚酯链的规律性。  相似文献   

2.
采用DCS、POM、SEM及力学性能测试,研究了不同对羟基苯甲醛和对苯二甲酸乙二醇酯含量的液晶共聚酯PET40/PHB60(LCP1)和PET30/PHB70(LCP2)的共混物与尼龙1010为基体的三元混体系。结果表明,液晶共混物的力学性能比单组分有明显提高,通过改变混合液晶中两组分的含量可调节其加工温度与粘度,从而满足了与尼龙1010共混的加工窗口要求。混合液晶的加入对尼龙1010的结晶与熔融  相似文献   

3.
DSC和SEM研究结果表明聚苯乙烯(PS)与一种热致液晶聚合物(LCP)(PHB/PET(60/40)共聚酯)完全不相容.共混体系具有与组分无关的Tg,并且表现出明显的两相结构.将PS进行化学改性(引入磺酸基团)制备成磺化聚苯乙烯(SPS),随中和盐离子的变化有:酸式、Li、Na、Zn和Mn盐五种形式.用DSC和SEM对LCP与SPS共混物的热性能和形态进行了分析和表征.共混体系有一个与组成相关,且明显低于纯SPS的Tg.这表明了PS与LCP的相容性因为磺酸基团的引入而得到了改善.同时用Fox方程计算了LCP的Tg.当SPS含量较低时(不大于50%)在各个共混体系中,所估算的LCP的Tg相互吻合.表明共混体系满足Fox方程的前提条件,即LCP与SPS形成相容体系.当SPS含量较低时(25%),LCP/SPS的共混物为较均一体系,断面光滑;而SPS含量较高时,在脆断面可以观察到纳米级的颗粒.电子能谱分析证明了这些颗粒是SPS负离子的聚集体.  相似文献   

4.
PET/PA66/液晶共聚酯酰胺共混体系的流变性能   总被引:5,自引:0,他引:5  
采用SEM1、热偏光显微研究了聚对苯二甲乙二酯(PET)/聚酰胺66(PA66)/热致液晶共聚酯酰胺(LC30)三元共混物的形态结构;利用Instron3211型毛细管流变仪研究了共混物的流变性能,结果表明:PET/PA66/LC30共混物为一热力学不相容的多相聚合物体系,LC30的加入提高了PET/PA66的相容性,有效地改善了PET/PA66共混物的流变性能,PET/PA66/LC30三元共混  相似文献   

5.
聚酯酰胺的合成及表征   总被引:1,自引:0,他引:1  
用两种方法合成了聚酯酰胺(PEA)共聚物.一种是两步法,即先合成对苯二甲酸乙醇酰胺(BAET)单体,然后与对苯二甲酸乙二酯(BHET)共缩聚;另一种是一步法.即在酯交换反应中直接添加乙醇胺(EA).两种方法制得的聚酯酰胺(PEA)共聚物测试证明了为产物,并分析了合成中的化学反应.  相似文献   

6.
聚酯酰胺的合成及表征   总被引:2,自引:0,他引:2  
 用两种方法合成了聚酯酰胺(PEA)共聚物.一种是两步法,即先合成对苯二甲酸乙醇酰胺(BAET)单体,然后与对苯二甲酸乙二酯(BHET)共缩聚;另一种是一步法.即在酯交换反应中直接添加乙醇胺(EA).两种方法制得的聚酯酰胺(PEA)共聚物测试证明了为产物,并分析了合成中的化学反应.  相似文献   

7.
本文研究工作表明,聚乙二醇(PEG)作为聚对苯二甲酸乙二酯(PET)/聚对苯二甲酸丁二酯(PBT)共混体系的结晶促进剂.不仅使聚合物分子链运动容易而有利于结晶时定向排列,晶体生成速度加快.而且使成核剂的成核效率提高,晶核生成速度加快,晶核数目增多而晶体尺寸减小.此外,PEG还部分参与了聚酯的酯交换反应,在低用量时有利于聚合物特性粘数提高,而用量增大则引起聚酯降解.由于PEG的这些作用,共混体系在PEG为6.0%时的模量及γ-衰减强度最大.动态力学性能最好.  相似文献   

8.
混合热计算和FTIR分析表明,聚对苯二甲酸乙二酯(PET)与聚苯膦酸二苯砜酯(PSPPP)具有一定的相容性,不同PSPPP含量的PET均具有较高的热稳定性,PET/PSPPP体系的阻燃性随阻燃剂PSPPP含量的增加而提高,PSPPP重量百分含量5%(下同)的阻燃PET体系的LOI值可达到30.1,由不同分子量的PSPPP构成的各种配比的PET体系,其表现粘度随切变速率的增大而降低,PSPPP的分子  相似文献   

9.
利用DSC、DMA、TEM和XPS对[PSF-PDMS-PHS]n/PSF共混物的相容性及表面组成进行了研究.结果表明,PDMS在共混物表面的富集与PSF均聚物和[PSF-PDMS-PHS]n中硬段的相容性有关;PDMS在相容的共混物体系表面的富集与对应的多嵌段共聚物组成基本相近;不相容共混物体系表面PDMS的富集程度相对较高,当共混物本体中有机硅含量从1%增至5%,表面层PDMS的含量迅速增加,可达到嵌段共聚物中PDMS的含量.  相似文献   

10.
郭霖 《高分子通报》1997,(3):195-196,F003
总结毛者提出的线型缩聚中当量系数的新定义及引入缩聚体系单体平均官能度的新方法,本文总结出了一套讲授数均聚合度计算问题的简单方法。  相似文献   

11.
Two series of aromatic-aliphatic random copolyesters(PEBTOXS)with diverse diol ratios have been synthesized by direct melting polycondensation.Two kinds of diols(glycol(EG)and 1,4-butanediol(BD))are used in combination in order to adjust crystallization and tensile properties,and three kinds of diacids(dimethyl terephthalate(DMT),diethyl oxalate(DEOX),and sebacic acid(SA))are involved.~1H-NMR spectra quantify both composition and structure,and show that the final contents in copolyesters appropriate to t...  相似文献   

12.
The synthesis, characterization, and some properties of new copolyesters of poly(butylene terephthalate) (PBT) and poly(ethylene terephthalate) (PET) based on L ‐arabinitol and xylitol are described. These copolyesters were obtained by polycondensation reaction in the melt of mixtures of 1,4‐butanediol or ethylene glycol and 2,3,4‐tri‐O‐benzyl‐L ‐arabinitol or 2,3,4‐tri‐O‐benzyl‐xylitol with dimethyl terephthalate. Their weight‐average molecular weights ranged between 7000 and 55,000, with polydispersities ranging from 1.4 to 4.7. Copolymers containing 1,4‐butanediol could be analyzed by NMR, and were found to have a statistical microstructure. All these copolyesters were thermally stable, with degradation temperatures well above 300 °C. With increasing amounts of alditol in the copolyester, the melting temperature and crystallinity decreased in both series, and the glass transition temperature increased for the PBT series and decreased for the PET series. Only PBT‐derived copolyesters containing a maximum of 10% alditol units showed discrete scattering characteristic of crystalline material. No substantial differences in either structure or properties were observed between the L ‐arabinitol and xylitol copolyester series. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5167–5179, 2008  相似文献   

13.
The synthesis, microstructure, and thermal behavior of a series of poly(ethylene terephthalate) (PET) copolymers containing nitroterephthalic units are described. These novel copolyesters were synthesized by transesterification followed by melt copolycondensation of dimethyl terephthalate and dimethyl nitroterephthalate mixtures with ethylene glycol. The molar ratio of the two comonomers in the feed varied from 95/5 to 25/75. Furthermore, PET and poly(ethylene nitroterephthalate) homopolymers were synthesized with the same method and comparatively studied. Copolyester compositions were practically the same as in the feed, and weight‐average molecular weights ranged from 10,000 to 60,000. The two monomeric units were randomly distributed along the polymer chain, and the experimentally determined average sequence lengths were in accordance with ideal copolycondensation statistics. Melting temperatures and enthalpies of the copolyesters decreased with increasing content in nitroterephthalic units, and they all showed a single glass‐transition temperature superior to that of PET. They appeared to be stable up to 300 °C, and thermal degradation occurred in two well‐differentiated steps. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3761–3770, 2000  相似文献   

14.
合成了一系列乙酸稀土盐(乙酸钇,乙酸镧,乙酸钕,乙酸镝),作为单组分催化剂,采用熔融缩聚法催化对苯二甲酸二甲酯、乙二醇和1,6-己二酸的共缩聚反应,制备了芳香族脂肪族共聚酯——聚(对苯二甲酸乙二酯-co-己二酸乙二酯)(PETA).通过1H-NMR,SEC,DSC及力学性能测试表征了聚合物的序列结构,分子量及分布,热性能及机械性能.结果表明,乙酸稀土盐单组分可催化共缩聚反应,效果优良,能够合成高分子量和较窄分子量分布的共聚酯,共聚酯具有较高的拉伸强度和断裂伸长率.  相似文献   

15.
Segmented copolyesters, namely, poly(butylene terephthalate)–poly(ethylene terephthalate‐co‐isophthalate‐co‐sebacate) (PBT‐PETIS), were synthesized with the melting transesterification processing in vacuo condition involving bulk polyester produced on a large scale (PBT) and ternary amorphous random copolyester (PETIS). Investigations on the morphology of segmented copolyesters were undertaken. The two‐phase morphology model was confirmed by transmission electron microscopy and dynamic mechanical thermal analysis. One of the phases was composed of crystallizable PBT, and the other was a homogeneous mixture of PETIS and noncrystallizable PBT. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2257–2263, 2003  相似文献   

16.
Copolyesters containing rigid segments (naphthalene and terephthalene) and flexible seg-ments (aliphatic diol) structure were synthesized from DMN/DMT/EG (2,6-dimethyl naphthalate/1,4-dimethyl terephthalate/ethylene glycol) ternary monomers with various mole ratios. Copolyesters having intrinsic viscosities of 0.52–0.65 dL/g were obtained by melt polycondensation in the presence of metallic catalysts. The effect of reaction tem-perature and time on the formation of the copolyesters was investigated to obtain an op-timum condition for copolyester manufacturing. The optimum condition for PNT (poly-ethylene naphthalate terephthalate) copolyester manufacturing is the transesterification under nitrogen atmosphere for 4 h at a temperature of 185±2°C followed by polymerization under 2 mm Hg for 2 h at a temperature of 280°C. Most copolyesters have better solubilities than poly(ethylene naphthalate) (PEN) and poly(ethylene terephthalate) (PET) in various solvents. The effect of the starting mole ratio of DMN, DMT, and EG on the thermal properties of the resulted copolyesters was also investigated using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Glass transition temperatures of copolyesters were in the range of 70.7–115.2°C, and 10% weight loss in nitrogen were all above 426°C. © 1995 John Wiley & Sons, Inc.  相似文献   

17.
A series of aliphatic–aromatic multiblock copolyesters consisting of poly(ethylene‐co‐1,6‐hexene terephthalate) (PEHT) and poly(L ‐lactic acid) (PLLA) were synthesized successfully by chain‐extension reaction of dihydroxyl terminated PEHT‐OH prepolymer and dihydroxyl terminated PLLA‐OH prepolymer using toluene‐2,4‐diisoyanate as a chain extender. PEHT‐OH prepolymers were prepared by two step reactions using dimethyl terephthalate, ethylene glycol, and 1,6‐hexanediol as raw materials. PLLA‐OH prepolymers were prepared by direct polycondensation of L ‐lactic acid in the presence of 1,4‐butanediol. The chemical structures, the molecular weights and the thermal properties of PEHT‐OH, PLLA‐OH prepolymers, and PEHT‐PLLA copolymers were characterized by FTIR, 1H NMR, GPC, TG, and DSC. This synthetic method has been proved to be very efficient for the synthesis of high‐molecular‐weight copolyesters (say, higher than Mw = 3 × 105 g/mol). Only one glass transition temperature was found in the DSC curves of PEHT‐PLLA copolymers, indicating that the PLLA and PEHT segments had good miscibility. TG curves showed that all the copolyesters had good thermal stabilities. The resulting novel aromatic–aliphatic copolyesters are expected to find a potential application in the area of biodegradable polymer materials. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5898–5907, 2009  相似文献   

18.
嵌段共聚酯的合成研究   总被引:2,自引:0,他引:2  
采用直接酯化法合成了一系列含间苯二甲酸的PEIT-PEG嵌段共聚酯,研究了聚合时间,聚合效率及聚酯的特性粘度与产物中间苯二甲酸含量及共聚酯分子量的关系,得出适于纺丝工艺及工业化生产的共聚酯分子量和间苯二甲酸的含量。  相似文献   

19.
The modification of poly(ethylene terephthalate) with 1,4‐cyclohexanedimethanol and the modification of poly(1,4‐cyclohexylenedimethylene terephthalate) with ethylene glycol or isophthalic acid retard the crystallization of the copolyester backbone, and over a wide range of comonomer concentrations, very slowly crystallizing, essentially amorphous copolyesters are formed. These amorphous copolyesters possess attractive physical properties such as toughness, low color, and chemical resistance, and since their first commercial introduction in 1977, these copolyesters have become the basis of a large and growing plastics business for Eastman Chemical Co. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5847–5852, 2004  相似文献   

20.
In this work, new investigations on the effect of comonomer sequential structure on the thermal and crystallization behaviors and biodegradability have been implemented for the biodegradable poly(butylene succinate‐co‐butylene terephthalate) (PBST) as well as aliphatic poly(butylene succinate) (PBS). At first, these copolyesters were efficiently synthesized from dimethyl succinate and/or dimethyl terephthalate and 1,4‐butanediol via condensation polymerization in bulk. Subsequently, their molecular weights and macromolecular chain structures were analyzed by gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR) spectroscopy. By means of differential scanning calorimeter (DSC) and wide‐angle X‐ray diffractometer (WAXD), thermal and crystallization behaviors of these synthesized aromatic–aliphatic copolyesters were further explored. It was demonstrated that the synthesized copolyesters were revealed to have random comonomer sequential structures with thermal and crystallization properties strongly depending on their comonomer molar compositions, and that crystal lattice structures of the new crystallizable copolyesters shifted from the monoclinic crystal of semicrystalline PBS to triclinic lattice of the poly(butylene terephthalate) (PBT) with increasing the terephthalate comonomer composition, and the minor comonomer components were suggested to be trapped in the crystallizable component domains as defects. In addition, the enzymatic degradability was also characterized for the copolyesters film samples. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1635–1644, 2006  相似文献   

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