Chain extension reactions of unsaturated polyesters with epoxy compounds

Unsaturated polyesters (UPE) were chain extended with three different epoxy group containing compounds. The molecular weight increase was monitored using gel permeation chromatography (GPC). The polymers obtained were characterized by FTIR and ¹H NMR, and styrene solubility and gel time. The polyesters were then diluted with styrene and cured with a radical initiator and compared with a commercial reference polyester. Thermal and mechanical properties of the cured polyesters were characterized by dynamic mechanical analysis (DMA) and thermal gravimetric analysis (TGA). The results show that UPE can be chain extended with epoxy containing compounds which substantially shortens the condensation polymerization during manufacture, without compromising their thermal and mechanical properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Microgelation in the curing reaction of unsaturated polyester resins

A series of unsaturated polyesters were synthesized with various chemical structures and molecular weights. These unsaturated polyesters were used to study the curing reaction with styrene by using gel permeation chromatography and differential scanning calorimetry. The variation of the size of microgel particles during the curing reaction in unsaturated polyester–styrene resins was studied by using gel permeation chromatography. The size and structure of the microgels depend strongly on the polymer chain length and the number of vinyl groups on each unsaturated polyester chain. Using the differential scanning calorimetric method, the conversion of styrene and polyester vinyl groups during the reaction was measured. The experimental results of this study revealed that microgel formation has a great effect on the curing reaction of unsaturated polyester resins. © 1994 John Wiley & Sons, Inc.     

Biobased polyester obtained from bifunctional monomers through metathesis of fatty acids as precursor to synthesis of polyurethanes

Biobased unsaturated aliphatic polyesters and polyurethanes were obtained from fatty acid monomers with double functionality synthesized through cross-metathesis of oleic acid and oleic alcohol. The chemical structure and thermal behavior of the monomers and polymers were analyzed by several physicochemical tests, and oscillatory rheometry and optical microscopy were used to determine their rheological properties and to observe the crystal formation of the obtained polyesters, respectively. It has been found that the polyesterification reaction depends on reaction temperature and to a lesser degree on both the reaction time and catalyst addition. The melt temperature and enthalpy of the obtained biobased polymers show that the monomer chain length has an effect on both the crystallinity and thermal transitions of the polymers, as can be explained by a group contribution analysis showing excellent correlation. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47095.     

Synthesis and properties of novel star-shaped polyesters based on l-lactide and castor oil

The topology of biodegradable polyesters can be adjusted by incorporating multifunctional polyols into the polyester backbone to obtain branched polymers. The aim of this study was to prepare the biodegradable-branched polyester polyols based on l-lactide and castor oil using the trifluoromethanesulfonic acid as a catalyst. FTIR and ¹H NMR spectroscopy measurements were used to estimate the molecular structure of the novel materials. The polyester polyol was synthesized by ‘‘core-first” method which involves a polymerization of l-lactide by using a castor oil as multifunctional initiator. Molar masses estimated by gel permeation chromatography and vapor pressure osmometry were in good correlation with calculated values based on hydroxyl number of obtained polymers. DSC measurements confirmed high crystallinity degree of the synthesized material. It was assessed that the molar masses of obtained polymers-influenced glass transition temperature significantly. The thermal stability was investigated by TG analysis, and the results have shown the dependence of weight loss on the arm length of the star-shaped polyesters. The thermal stability of star-shaped polyesters significantly decreased with degradation of polyester polyol obtained in acid solution.     

Torque‐rheometry investigation of model transreactions involving condensation polymers. I. Polyesters

The chemical transformations taking place when poly(ethylene terephthalate) (PET) or poly(ethylene naphthalate) (PEN) are blended in the melt with different low molar mass substances containing hydroxyl, carboxyl, or amine functional groups have been investigated as models of the transreactions, undergone by the polyesters in reactive blending operations. The polyester molecular weight changes caused by the alcoholysis, acidolysis, aminolysis, and esterolysis reactions have been monitored by torque‐rheometry, using a Brabender Plasticorder static mixer. The degradation of the polyesters by hydrolysis was also studied, under similar conditions, by the addition of a water‐releasing substance (wet polyamide‐6), and was shown to occur quite rapidly, although most of the added water was lost by flash vaporization caused by the high temperature of the polyester melt. It has been shown that the rate constants of the reactions leading to breakage of the inner ester bonds of the polyester macromolecules decrease in the following order: aminolysis (with aliphatic amines, either primary and secondary) > alcoholysis (with aliphatic alcohols) ≈ hydrolysis > acidolysis (with aromatic acids) ≥ acidolysis (with aliphatic acids) ? aminolysis (with aromatic amines) > alcoholysis (with phenols) ? esterolysis. POLYM. ENG. SCI. 46:139–152, 2006. © 2005 Society of Plastics Engineers     

环氧树脂改性超支化聚酯的合成及性能

以偏苯三酸酐、环氧氯丙烷及甲基丙烯酸缩水甘油酯为原料合成了超支化聚酯(HBP),再通过超支化聚合物的羧基与环氧树脂环氧基的反应得到环氧改性超支化聚合物;用GPC1、H-NMR、DSC、TGA表征了环氧改性超支化聚合物的结构和热性能;比较了不同环氧树脂用量改性前后树脂的光反应活性以及光固化涂层的耐擦洗性和硬度,测定了凝胶率-曝光时间曲线;以环氧改性超支化聚合物配制了光刻胶,在混合光源以及接触曝光的条件下,分辨率达到2~3μm,且图像十分清晰,断面整齐。环氧树脂用量为HBP羧基物质量的70%左右时,改性的超支化聚酯的光固化活性有明显提高,力学性能得到明显改进。     

Novel DCPD-modified polyester containing epoxy groups: thermal,viscoelastic, and mechanical properties of their wood flour filled copolymers

In this article, the synthesis of novel DCPD-modified polyesters containing epoxy groups and their possible utilization as polar matrices for wood flour filled copolymers have been studied. The novel DCPD-modified polyester containing epoxy groups was prepared during three-step process. First, the addition reaction of maleic acid to DCPD norbonenyl double bond has been performed. Then, the polyesterification of acidic ester of DCPD, cyclohex-4-ene dicarboxylic anhydride, and ethylene glycol (ethane-1,2-diol, EG) or neopentyl glycol (2,2-dimethyl-1,3-propanediol, NP) in the presence of catalyst was carried out using melt condensation technique. Finally, the oxidation process of prepared DCPD-modified polyesters led to obtain DCPD-modified polyesters containing epoxy groups. The structural characterization of prepared DCPD-modified polyesters containing epoxy functionality has been carried out using FTIR and HNMR spectroscopic methods. The thermal, viscoelastic, and mechanical properties of their unfilled and wood flour filled copolymers have been studied by DSC, DMA, TGA analyses, three-point bending test, and Brinell’s hardness. The performed investigations indicated that novel DCPD-modified polyesters containing epoxy groups can be successfully applied as polar matrices for preparation wood flour filled copolymers due to their “compatibility” with hydrophilic wood flour surface which resulted with stronger interactions between wood and polymer surface and thus producing copolymers which were characterized by improved thermo-mechanical properties compared to unfilled copolymers.     

Synthesis of new polyesters with methacrylate pendant groups

Summary A catalytic process for synthesis of new polyesters with methacrylate pendant groups is presented. Thus, zinc succinate catalyzed reaction of succinic anhydride with glycidyl methacrylate (GMA) in dimethoxyethane gives linear oligoesters with low molecular weights (1380-2400 Da). The polyester formation takes place via simultaneous ring opening of the cyclic anhydride and oxirane units. GMA component can be partially replaced with cyclohexeneoxide to obtain polyesters with methacrylate pendant groups in various percentages. Nearly colorless waxy polymers are obtained in excellent yields (69–97%) within 48–60 h. at 90 °C. In the study structure of the polymers have been elucidated by conventional spectroscopic techniques and photo-crosslinking of ability of their thin films have been tested by monitoring intensity of methacrylate double bonds, using IR-spectrometry methodology.     

Blocked isocyanates and isocyanated soybean oil as new chain extenders for unsaturated polyesters

Two different blocked isocyanates, diphenylmethane–bis‐4,4′‐ethyleneurea and diphenylmethane–bis‐4,4′‐carbamoil–ϵ‐caprolactam, and isocyanated soybean oil were used as chain extenders for low‐molecular‐weight unsaturated polyesters. Oligomeric polyesters (molecular weight = 600–700), taken from a manufacturing process in the sixth hour of a 16‐h polyesterification reaction, were reacted with these chain extenders, and the desired chain lengths (molecular weight = 1000–1500) were obtained in a very short time through the reaction of the chain extenders with the polyester end groups. The increase in the molecular weight was monitored with gel permeation chromatography. The obtained polymers were characterized with Fourier transform infrared and ¹H‐NMR and with styrene solubility and gel time measurements. After dilution with styrene, the polyesters were cured with a radical initiator. The thermal and mechanical properties of the cured polyesters were examined with dynamic mechanical analysis and thermogravimetric analysis tests and then compared to those of a commercially available reference unsaturated polyester. The results show that unsaturated polyesters can be chain‐extended with these compounds to shorten the polyesterification time substantially without alterations of the styrene solubility or gel time of the polyesters. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

4,4'/2,4'-二苯基甲烷二异氰酸酯/多元醇本体聚合流变动力学

采用转矩流变仪模拟双螺杆挤出反应条件,分别在无催化剂和铋/锌复合催化剂作用下进行4,4'/2,4'-二苯基甲烷二异氰酸酯/聚四氢呋喃醚二醇/1,4-丁二醇本体聚合,结合二维流动简化假设、黏度/分子量关联式和Arrhenius方程,建立了热塑性聚氨酯(TPU)重均分子量与反应体系转矩、温度的流变动力学方程,分别拟合得到无催化剂和催化剂作用时体系转矩与重均分子量的关联式;发现采用流变动力学方程模拟的TPU平均分子量与实时取样后采用凝胶渗透色谱法测定的结果吻合良好,采用流变动力学方法测量方便迅速,能提供整个反应过程中TPU平均分子量的变化情况。     

稀土元素化合物在聚酯聚合工艺中的催化作用

以不同的稀土金属元素化合物及稀土化合物/三氧化二锑复合物分别用作聚酯酯交换和缩聚催化剂,对各工艺参数进行分析,并对产品性能进行测试与表征.结果表明:稀土化合物可作为聚酯酯交换的催化剂和缩聚助催化剂;使用稀土化合物/三氧化二锑复合催化剂,能有效提高酯交换效率,缩短反应时间,降低酯交换开始温度,所得聚酯产品的色相优于普通三氧化二锑催化所得聚酯,结晶度比普通三氧化二锑催化所得聚酯的高,且重稀土有机化合物比轻稀土无机化合物催化效率更高.     

回用乙二醇制备聚酯的评价研究

利用小试聚合装置对新鲜乙二醇(EG)和聚酯生产中的馏出EG在乙酸锑和乙二醇锑2种催化剂条件下聚合评价,制备超有光聚酯切片和膜级聚酯切片,对切片的色相进行检测分析。结果表明:在乙酸锑、EG催化剂条件下,新鲜EG、回用EG制备的膜级聚酯切片要比同条件下制备的超有光聚酯L值、b值高。在乙二醇锑催化剂条件下,新鲜EG、回用EG制备的膜级聚酯切片要比超有光聚酯L值、b值高。膜级聚酯要比超有光聚酯的高真空反应时间长。     

Synthesis and characterization of APTMS/melamine cured hyperbranched polyester-epoxy hybrid coatings

An epoxy-terminated hyperbranched polyester (EPHBP) was prepared by the reaction of hyperbranched polyester (HBP) and epichlorohydrin (EPH). Herein, we have synthesized a new kind of highly epoxy ended branched polyester to enhance the chemical bonding at the interfaces and to reduce the melt viscosity. The structural investigation of the hyperbranched polyesters was carried by spectroscopic techniques such as nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR) while molar masses were determined using gel permeation chromatography (GPC). The effect of the content of hexamethoxy methyl melamine (HMMA) and 3-amino propyltrimethoxysilane (APTMS) mixture on the thermal, mechanical and interfacial properties of EPHBP resins were also studied. The thermal, dynamic mechanical and mechanical properties of the heat cured coating films were also investigated. The combined analysis of the results indicate that the introduction of APTMS results in the enhancement of the thermal stability, glass-transition temperature (T_g), storage modulus, tensile strength and contact angle of the cured films. The improvement in properties depends on the APTMS content of the cured films. The cured films have also shown higher elongation at break due to the use of HMMA and presence of unmodified epoxide groups which indicates good flexibility and toughness of the coating films.     

Linear polymers with sulfur in the main chain,I . Polyesters derived from interfacial polycondensation of 4,4′-thiodiphenol and/or bisphenol-A with adipoyl dichloride

Polyesters having sulfur atoms in the main chain were synthesized from 4,4′-thiodiphenol (TDP) and adipoyl dichloride (APC) by both solution polycondensation and interfacial polycondensation. The specific viscosity of the product from interfacial polycondensation was higher than that of the product obtained by the solution method. Influences of solvent and phase transfer catalyst on the specific viscosity were investigated in the interfacial polycondensation. As for viscosity, the polyester synthesized with 1,1,2,2-tetrachloroethane (TCE) as the organic phase and tetra-n-butylammonium bromide (Bu₄NBr) as the catalyst indicates the highest value. Bisphenol-A was co-polycondensated with TDP and APC to improve the toughness of the polyester from TDP. Properties of the polymers were evaluated with thermogravimetric analysis, differential scanning calorimetry, FTIR and ¹H NMR spectroscopic analysis, viscoelastic spectrometer (DMA), oxygen gas permeability (GTR), and gel permeation chromatography. The polyesters have a very low value of oxygen gas permeability; especially the value of the polyester from TDP and APC was lower than that of PET.     

钛系聚酯催化剂催化活性的影响因素研究

以二氧化钛(TiO2)为消光剂,采用钛系催化剂STiC-01或锑系催化剂乙二醇锑,在2 L间歇式聚合反应釜中制备半消光PET切片。根据PET切片的特性黏数和色度(L值及b值),比较了催化剂的催化活性,并研究了催化活性的影响因素。结果表明:在相同的聚合工艺条件下,STiC-01的钛用量为5μg/g(相对于PET质量)时的催化活性与乙二醇锑的锑用量为250μg/g(相对于PET质量)时的相当,PET切片的特性黏数达0.676 dL/g,钛系PET切片的L值高于锑系PET的,b值相当;磷化合物和镁化合物的用量应适当控制;催化剂在酯化前加入,TiO2在酯化后加入,STiC-01的催化活性不受TiO2的影响;相比乙二醇锑,STiC-01的催化活性受原料质量的影响小。     

Photopolymerization of dendritic methacrylated polyesters. I. Synthesis and properties

The so-termed starburst dendritic polyesters differ from classical polymers by their structural symmetry, high degree of branching, and high density of terminal functionality. The divergent synthesis of a series of polydisperse dendritic polyesters based upon pentaerythritol and 1,2,4-benzenetricarboxylic anhydride, modified by glycidvl methacrylate and methacrylic anhydride, is described, proceeding in a stepwise growth manner starting from an “initiator core,” building branched arms. These materials have about eight (two samples), 12, or 16 methacrylate double bonds (indicated as D-1-OH, D-1, D-2, and D-3, respectively) at the chain extremities on each molecule. The rheological behavior was investigated by measuring the dynamic viscosity of the dendritic polyesters. The viscosities of the dendritic polyesters largely decrease in the order D-1-OH, D-1, D-2, and D-3 at lower frequency, but the viscosities of D-1-OH and D-1 decrease dramatically at higher frequency. Using a viscometric cup, the flow time of the dendritic methacrylated polyesters was compared with epoxy acrylate-modified unsaturated polyester of a linear type and it was shown that the flow time for the former is only one-third of that for the latter. The thermal mechanical properties and glass transition temperatures of the UV-cured films increase with the degree of terminal functionality. © 1996 John Wiley & Sons, Inc.     

蓖麻油酸基聚酯多元醇的合成研究

以可再生资源蓖麻油制备的蓖麻油甲酯、己二酸、乙二醇为原料,钛酸四正丁酯为催化剂,经酯化、缩聚合成蓖麻油酸基聚酯多元醇,考察了反应时间、催化剂、蓖麻油甲酯对聚酯多元醇热稳定性能的影响,采用凝胶色谱(GPC)、红外光谱仪(IR)、示差扫描量热仪(DSC)对蓖麻油酸基聚酯多元醇的相对分子质量、结构、热稳定性进行了系统的表征。实验表明,在醇酸(己二酸∶乙二醇)比为1.15、催化剂质量分数0.04%～0.05%、温度180℃,真空缩聚2h的条件下,制得相对分子质量为2600～3800、分布指数(PDI)为1.89～2.44的不同蓖麻油酸含量的聚酯多元醇,蓖麻油酸基聚酯多元醇的熔点随着蓖麻油酸含量的增加而降低。     

Synthesis and characterization of azo‐based acrylate polymers for use as nonlinear optical materials

In this work, high molecular weight azo polymers were synthesized by incorporating the azo monomer into a base polymer through their reactive functional groups. Copolymers of methyl methacrylate and methacrylic acid (with varying concentrations of carboxylic acid group) were synthesized. These were then reacted with epoxy‐terminated azo molecule by carboxylic acid–epoxy reaction. The functionalized systems show excellent film homogeneity and optical clarity. The series of copolymers were characterized using FTIR, NMR, UV–vis spectrometry, gel permeation chromatography, elemental analysis, thermogravimetric analysis, and differential scanning calorimetry. The polymer films coated on ITO glass slides were poled and their order parameters were calculated to check the stability of oriented dipoles. Temporal stability, checked up to 120 h under ambient conditions, was found to be excellent. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 425–431, 2007     

Synthesis and characterization of a novel unsaturated polyester based on poly(trimethylene terephthalate)

Unsaturated aromatic polyesters were obtained by glycolysis of poly(trimethylene terephthalate) with cis-2-buten-1,4-diol followed by a solid-state polymerization. The glycolysis was performed in a batch mode as well as through a continuous process in a twin screw extruder. The degradation and subsequent rebuilding of the polymer chain during the course of reaction was followed by means of inherent and melt viscosity measurements, and ¹H NMR terminal group analysis of the intermediates and the final products. Structural investigations revealed that this new approach resulted in melt processible unsaturated polyesters with cross-linkable sites having similar characteristics to that of the virgin saturated polyester. Although the processing temperature for the different reaction steps was sufficiently high (180−260 °C), no thermally induced cross-linking of the incorporated unsaturated bonds could be evidenced indicating that the obtained products remained stable during the production stage. For comparison purposes, a commercial unsaturated polyester (Vestodur^©) was included in the investigations. UV irradiation of thin polyester films did not result in cross-linked products but in cis-trans isomerization of the incorporated bisoxybutenyl unit.     

Synthesis and crystallization behaviors of highly fluorinated aromatic polyesters

Studies on fluorine containing condensation polymers are limited compared to that of fluorine containing addition polymers. In this report, highly fluorinated aromatic polyesters were synthesized by a polycondensation reaction of tetrafluorophthalic anhydride with ethylene glycol. Viscosity, solubility, thermal properties and crystallization behaviors of fluorinated polyesters were investigated using IR, ¹⁹F NMR, DSC, GPC, polarized optical microscope and rheometer. The fluorinated polyester is insoluble in most organic solvents, such as acetone, ethyl acetate, chloroform, THF, and trichloromethane. However, it is soluble in highly polar solvents, such as dimethylsulfoxide, dimethylformamide and dimethylacetamide. The fluorinated polyester (o-PETF) is a crystalline polymer with a crystallization enthalpy of 35.2 J/g and a broad crystallization temperature range from 54 to 130 °C. Average crystalline growth rate is 4.2 μm/min at 110 °C in the preliminary 30 min. Spherulite growth was observed at the temperature when the dendrites begin to melt. Crystallization property of o-PETF may be ascribed to the higher mobility of fluorinated polyester chains and dipolar contribution of carbon-fluorine bonds.