聚酯及共聚酯化学组成分析

介绍用甲醇醇解法把聚酯或共聚酯解聚成二元酸二甲酯和二元醇。用差示扫描量热 (DSC)、气相色谱及气相色谱 质谱联用仪对醇解液进行检测分析 ,得到聚酯的化学组成。     

耐温共聚酯的合成及其性能研究

本文提供了一种耐温的改性共聚酯,采用不同的二元醇合成改性PET。研究酯化温度、催化剂及不同量的功能性单体合成耐温聚酯材料的影响。结果表明：酯化温度在255℃,催化剂的量在300×10^-6,异山梨醇与1,4-环己烷二甲醇的复合含量为30%其综合性能最好。该共聚酯的玻璃化转变温度(Tg)比一般的聚对苯二甲酸乙二醇酯更高,且具有更优异的综合性能。     

多组分共聚酯热解动力学探讨

用微量热天平测定了多组分共聚酯与ＰＥＴ的ＴＧ与ＤＴＧ曲线．分析了它们的热裂解过程．并且进行了热解动力学研究．结果显示，多组分共聚酯与ＰＥＴ的热裂解均为一级反应．表观反应级数ｎ大约为１左右，多组分共聚酯的热稳定性较ＰＥＴ稍高．     

聚丁二酸乙二醇酯及其共聚酯的生物降解性能

通过降解过程的质量损失率、相对分子质量及其分布、热性能、表面形貌等评价手段,重点考察了Aspergillus niger脂肪酶对聚丁二酸乙二醇酯(PES)和聚(丁二酸乙二醇-共-对苯二甲酸乙二醇酯)(PEST)的降解性能。结果表明:PES在脂肪酶溶液中具有较好的生物降解性能,随着对苯二甲酸摩尔含量的增加,PEST的质量损失率呈现先增加后逐渐减少的趋势;随着酶解时间的延长,残留部分的PES、PEST的相对分子质量均呈下降趋势;残留部分的PES、PEST的熔点随降解时间的延长变化不大,熔融热焓有所增加;聚酯薄膜表面产生了不同程度的沟槽、孔洞和裂纹。可以推测,PES及PEST的生物降解首先发生在无定形区,并且大分子链段发生的是随机断裂。     

PET与PTT共聚酯的合成及其性能研究

采用直接酯化法合成了不同比例的PET与PTT共聚酯,研究了所得共聚酯的热性能、力学性能及染色性等与不同组成比之间关系。     

一种可降解共聚酯的合成及表征

采用对苯二甲酸、1,4-丁二醇和脂肪酸为原料,以直接酯化法缩聚合成了生物可降解的高分子质量脂肪-芳香族共聚酯,并分析表征了此共聚酯的结构、分子质量、力学性能、流变性能及降解性能等。     

含有草酸酯的共聚酯的合成与性能研究

以草酸二乙酯(DEOX)为原料，采用熔融缩聚法制备了草酸乙二醇酯与对苯二甲酸乙二醇酯、癸二酸乙二醇酯的无规共聚酯(PETOXS)。考察了共聚酯的热性能、水解性能和拉伸性能。结果表明，共聚酯的熔点、结晶行为依赖于组成，芳香族聚酯含量少的共聚酯的热分解温度受两种脂肪族聚酯单元组成的影响。PET含量多，共聚酯的水解性能差；而聚草酸酯含量高，水解快、模量高、应变小。     

PCT高性能聚酯工程塑料

综述了以环己烷二甲醇与对苯二甲酸二甲酯合成PCT(聚对苯二甲酸环己烷二甲醇酯)树脂及其本体树脂PCT的加工技术(包括GFRPCT、共混等),对PCT树脂的物理、机械性能及其典型应用也作了介绍。     

多组分共聚酯的制备及亲水性研究

采用对苯二甲酸(PTA)直接酯化法,在第一酯化阶段添加山梨醇,第二酯化阶段添加间苯二甲酸二乙酯-5-磺酸钠和聚乙二醇,合成多组分亲水共聚酯;研究了共聚酯的化学结构、熔融过程、热稳定性及亲水性。结果表明:引入的多组分均参加了共聚反应,得到产物为多组分共聚酯;随着山梨醇添加量的增加,共聚酯的特性黏数([η])变小,结晶性能变差,热稳定性下降,亲水性增大;当添加的山梨醇相对PTA的摩尔分数为1.0%时,共聚酯的[η]为0.558 dL/g,熔点为232.91℃,结晶度为22.43%,起始分解温度388.1℃,与水的表面接触角减小到46°。     

Thermotropic liquid crystalline copolyesters. II. Synthesis and thermal characterization of copolyesters of terephthalic acid,methyl hydroquinone and 1,4-butane diol

The synthesis and thermodynamic evaluations of a series of random copolyesters based on terephthalic acid, methyl hydroquinone and 1,4-butane diol are presented. The copolyester composition was varied by altering the relative concentrations of methyl hydroquinone and 1,4-butane diol. The copolyesters display thermotropic transitions. The enthalpy changes during mesophasic transition display a minimum corresponding to equimolar composition. The copolyester with 75 mol% of spacer diol exhibited the lowest nematic transition temperature (190-6°C). At this composition the nematic mesophase was most stable (δT_N = 115-6°C). ΔH_N-1 and ΔS_N-1 decrease with increasing rigid diol content. The isotropization temperatures were almost comparable since the largest mesogenic residues are similar in aspect ratio. These residues are required to melt prior to isotropization.     

Network copolyesters from benzenepolycarboxylic acids and 1,6-hexanediol

Network copolyesters were prepared from trimesic (Y), pyromellitic (X) or mellitic (Y_H) acids and 1,6-hexanediol (6G). Prepolymers prepared by meltpolycondensation were cast from dimethylformamide solution and postpolymerized at 260°C for 6h to form a network. The resultant films were transparent, flexible and insoluble in any organic solvents. Degree of reaction estimated from the infrared absorbance of ester and methylene groups was almost the same for all films, 94–96%. X-ray diffraction intensity curves and densities showed that the ordering of networks was decreased by the copolymerization, which was remarkable for 6G–X/Y_H copolymer films and was consistent with the higher decreases of heat-distortion temperature for these copolymer films. The copolymerization also caused decrease of thermal stability, tensile properties and alkali resistance and increase of dye absorption.     

Synthesis and characterization of siloxane copolyesters containing phenylindane linkages

A novel series of siloxane copolyesters containing 1,1,3‐trimethyl‐3‐(p‐hydroxyphenyl)‐5‐indanol (phenylindane bisphenol), diphenyl terephthalate (DPT), diphenyl isophthalate (DPI), and eugenol end‐capped siloxanes in varying ratios were prepared at a temperature range of 200–290°C under reduced pressure using dibutyl tin dilaurate catalyst by melt polycondensation. The siloxane‐containing copolyesters were characterized by infrared and ¹H NMR spectroscopy, elemental analysis, solution viscosity, thermogravimetric analysis, differential scanning calorimetry, and X‐ray diffraction. The effect of incorporation of siloxane moiety was studied on the properties of phenyl indane/DPT/DPI coplyester. The glass transition temperatures of copolyesters were decreased from 235 to 124°C by incorporation of 10% eugenol end‐capped siloxane without affecting the thermal properties. All copolyesters were found to be soluble in commonly used organic solvents and had film forming properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2668–2674, 2006     

Extrusion,fiber formation,and characterization of thermotropic liquid crystalline copolyesters

The flow behavior and the effect of the spinning conditions on the fiber properties and structure of the copolyesters, i.e., samples of copoly(p-hydroxybenzoate-bisphenol A terephthalate), were investigated. The experimental results indicated that the apparent viscosity was affected significantly by shear rate, melt temperature, and p-hydroxybenzoate unit content; and the copolyester melts exhibit highly shear thinning behavior. The fiber modulus increase with the increase in extrusion temperature and draw-down ratio, and the tensile properties could be improved when a high spin draw ratio was used. High birefringence, indicating the presence of mesophase, was observed on a hot-stage polarizing microscope. Scanning electron microscopy revealed that the fibers spun at relatively high temperature had a well-developed, highly oriented fibrillar structure. The fibers spun at low temperatures, however, were poorly oriented and nonfibrillar in character. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1389–1397, 1997     

Comparative effects of resorcinol and bisphenol A in non-mesogenic units in liquid crystalline copolyesters containing a flexible spacer

Two series of copolyesters containing both linear mesogenic and nonlinear, non-mesogenic aromatic ester units, each with a decamethylene spacer, were prepared and characterized for the effect of the non-mesogenic unit and the spacer on the stability of the liquid crystalline (LC) phase. The mesogenic units were formed from the reaction of 2-chlorohydroquinone and 1,10-bis(4-carboxy-phenoxy)decane while the non-mesogenic units were derived from reacting either resorcinol (Series I) or bisphenol A (Series II) with the latter monomer. The non-mesogenic units containing bisphenol A were found to be more efficient in destroying liquid crystallinity of the copolyesters than were resorcinol-containing units. However, the presence of a flexible spacer in each unit allowed the copolymers to form a nematic LC phase even at contents of the resorcinol and bisphenol A non-mesogenic units as high as 70 and 60 mol %, respectively.     

Structures and properties of easily dyeable copolyesters and their fibers respectively modified by three kinds of diols

Three kinds of modified poly(ethylene terephthalate) copolyesters were synthesized, using sodium‐5‐sulfo‐bis‐(hydroxyethyl)‐isophthalate as the third monomer, 1,3‐propanediol (PDO), 2‐methyl‐1,3‐propanediol (MPD), and 2,2‐dimethyl‐1,3‐propanediol (neopentyl glycol or NPG) as the fourth monomer, respectively. The copolyester fibers were also prepared by melt spinning and drawing processes. The effect of PDO, MPD, and NPG on the synthesis and spinning process was investigated, and the structures and properties of both copolyesters and the produced fibers were characterized. The results exhibited that the structural difference of PDO, MPD, and NPG played an important role in the synthesis and spinning process, and significantly affected the structures and properties of both copolyesters and the produced fibers, which thereby resulted in the difference in terms of dyeability improvement of copolyester fibers. The dyeing at boiling temperature under normal pressure experiments of copolyester fibers in both disperse dyebath and cationic dyebath revealed that incorporation of the fourth monomer could improve the dyeability of copolyester fiber, and copolyester fiber containing MPD unit had better dyeability due to a looser, more accessible structure when compared with the fiber containing PDO or NPG unit. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

二氧化氯的开发与应用

介绍了二氧化氯的性质、生产方法以及稳定型二氧化氯、粉末二氧化氯的制备方法。阐述了国内外开发现状和发展趋势。     

New polymer syntheses VIII. Synthesis,characterization and morphology of new unsaturated copolyesters based on dibenzylidenecycloalkanones

A new interesting class of linear, unsaturated copolyesters based on dibenzylidenecycloalkanones has been synthesized by interfacial polycondensation of isophthaloyl chloride or sebacoyl chloride with 2,5-bis(p-hydroxybenzylidene) cyclopentanone I, 2,6-bis(p-hydroxybenzylidene) cyclohexanone II, 2,6-divanillylidenecyclohexanone III or 2,7-bis(p-hydroxybenzylidene)cycloheptanone IV at ambient temperature. The resulting copolyesters were characterized by elemental analyses, IR spectroscopy, and solubility. Additionally, inherent viscosities of copolyesters in the range 0·53–0·98dlg⁻¹ were determined. The thermal properties of the polymers were evaluated by TGA and DSC measurements and correlated with their structural units. The crystallinity of some copolyesters was examined by X-ray analysis. In addition, the electrical properties of the copolyesters were tested and the morphology of selected examples of the copolyesters was examined by scanning electron microscopy. © 1998 Society of Chemical Industry     

Review of crosslinked and non‐crosslinked copolyesters for tissue engineering and drug delivery

Novel degradable biomedical materials are found to have huge potential applications in fields such as drug delivery and release, orthopedic fixation support and tissue engineering. Utilization of polymers as biomaterials has greatly impacted the advancement of modern medicine. In this review, some new degradable biomedical copolyesters reported in recent years are introduced and discussed in combination with some of our research results, including non‐crosslinked copolyesters, crosslinked copolyesters and their corresponding derivatives. The molecular design, chemical structures and related properties of these biodegradable copolyesters are reported. In summarizing the review, the development, potential applications and future directions of degradable biomedical copolyesters are discussed. © 2013 Society of Chemical Industry     

Microhardness of PET-based liquid crystalline copolyesters: influence of the microstructure

The Vickers microhardness of PET-based liquid crystalline copolyesters has been investigated. The copolyesters have been synthesized by transesterification of PET with equimolar amounts of sebacic acid (S) and hydroquinone (Q) (or 4,4′-dihyroxybiphenyl (B)) and with varying amounts of 4-hydroxybenzoic acid (H). The variation of the Vickers microhardness of PET-S-Q-H and PET-S-B-H liquid crystalline polyesters with the composition have been interpreted by the microstructure of the materials. The increase in the concentration of 4-hydroxybenzoic acid (H) in both types of copolyesters leads to an increase in intermolecular distance and to enlargement of the domain size. This, on its, turn, leads to a decrease in the materials' microhardness. The effect that the mixing time of the reactive blends of equimolar amounts of PET and poly(phenylene sebacate) (PQS) PET/PQS has upon the microhardness values has been also studied. The variation of the microhardness of PET/PQS blends prepared for different mixing times follows the same tendency as that of the melting enthalpy (i.e. the degree of crystallinity). Both parameters have lower values with the longer mixing time. The decreased crystallinity during the transreaction results into materials having higher creep rate under load.