Änderung der Oxidationsstufe des Kobaltund Vanadium-Beschleunigers während der Härtung ungesättigter Polyesterharze

During the free radical copolymerization of unsaturated polyesters with styrene the metal in the accelerator is oxidized and reduced alternatively. In the case of cobalt and vanadium accelerators this causes a change in the colour of the resin. This change in the colour makes it feasible to determine colorimetrically the content of the higher and the lower valency of the metal during the polymerization.     

Preparation of an acrylics‐grafted polyester and its aqueous dispersion

An investigation was undertaken to develop a new class of water‐borne polyesters having excellent dispersibility without using emulsifiers. Grafting reactions of hydrophilic acrylics to polyesters and the relationships between reaction conditions and the dispersion diameters are discussed. Aqueous dispersions of particles having small diameters were obtained by use of an unsaturated polyester. Particle diameters were related to the grafting efficiency that could be enhanced by copolymerization of reactive monomers with the unsaturated bonds of polyesters. The relationships between particle diameters and the kind of acrylic monomers were described by the copolymerization reactivity ratio of the unsaturated polyester and acrylic monomers. Also, the influences of the solvency of the reaction medium and the influence of concentration of unsaturated bonds of the polyesters in the reaction medium were discussed to explain the low reactivity between the unsaturated bonds and acrylic monomers. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1817–1825, 1999     

Unsaturated polyester containing myrcene–maleic anhydride Diels–Alder adduct

Myrcene–maleic anhydride Diels–Alder adduct and the corresponding diacid were used as monomers for unsaturated polyesters. The polyesters exhibited air-drying properties on cross-linking with styrene.     

Effect of γ-irradiation on chlorendic acid based unsaturated polyesters

The effect of gamma ray irradiation on chlorendic acid based unsaturated polyesters was studied. Four different types of unsaturated polyesters, made by varying the molar ratios of chlorendic acid to isophthalie acid were irradiated with a Co⁶⁰ qource. After irradiation, the chlorine content decreases rapidly as the isophthalate content in the polyester chain increases. As the chlorendle acid content increases, the change in acid value after irradiation decreases. The increase in intrinsic viscosity is quite marked in high isophthalate containing polyesters after gamma ray irradiation and there is a noticeable decrease in intrinsic viscosity after gamma irradiation of high chlorendic acid containing polyesters. The effect of gamma irradiation on the percentage of cis and trans forms of these polyesters was studied with the help of infrared spectra. It appears that as the chlorendic acid content increases, on gamma irradiation conversion from trans unsaturation to cis unsaturation increases rapidly.     

Study of unsaturated polyester and vinylester morphologies using excimer laser surface treatment

A technique based on the use of an ArF excimer laser (193 nm) to analyze the morphology of the unsaturated polyester and vinylester networks has been developed. This method is based on the use of the differences between the thresholds at which ablation of the various constituent phases of the materials occurs. After having determined the ablation threshold of a polystyrene, various surface treatments using excimer lasers fluence around this threshold were applied to unsaturated polyesters and vinylester. In the latter case, a two-phase structure consisting of microgels in a polystyrene phase was shown by scanning electron microscopy observations, allowing us to conclude that the mechanisms by which vinylester and unsaturated polyester networks are formed are similar. We also observed that the two-phase structure of the vinylester matrixes, unlike that of the unsaturated polyesters, is organized rather than random-structured, which could represent a major parameter contributing to the very good hydrolysis stability of these materials. In the event of degradation by osmotic mechanisms, the organized structure network would enable limiting of the development of the osmotic pressures by distributing the forces within the material, thus avoiding crazing. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1703–1714, 1997     

Chemical modification of unsaturated polyesters influence of polyester's structure on thermal and viscoelastic properties of low styrene content copolymers

In this study, the chemical modification of unsaturated polyesters and the influence of polyester's structure on thermal and viscoelastic properties have been presented. The structure of unsaturated polyesters obtained in polycondensation of cyclohex‐4‐ene‐1,2‐dicarboxylic anhydride (THPA), maleic anhydride and only one suitable symmetrical glycol: ethylene glycol or 1,4‐butanediol (BDO) or 1,6‐hexanediol has been modified by peracetic acid. The selective oxidation of unsaturated polyesters conducted in mild time and temperature conditions was a successful and effective method to prepare new materials/unsaturated epoxy polyesters/containing epoxy groups in cycloaliphatic rings and carbon–carbon double bonds in polyester chain. The unsaturated epoxy polyesters were capable of both copolymerization with vinyl monomer and polyaddition reactions with suitable curing agent. Therefore, they were successfully used as a component of low styrene content copolymers. As was confirmed by DSC, DMA, and TGA analyses, polyester's structure had significant influence on thermal and viscoelastic properties of styrene copolymers. The properties of styrene copolymers prepared from unsaturated epoxy polyesters were considerably better compared with those obtained for styrene copolymers from unsaturated polyesters.© 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Gezielte Synthese von Dimerfettsäuren

Selective Synthesis of Dimer Fatty Acids Dimer fatty acids are aliphatic C₃₆-dicarboxylic acids, and are important raw materials for the manufacture of polyamides, polyesters, heavy duty lubrication oils and plasticizers. They are made by condensation of two unsaturated fatty acids in the presence of a catalyst. Because of the complicated reaction mechanism a complex mixture is obtained. Therefore only insufficient information in regard to the structure has been obtained. We report the synthesis of single isomers of linear and branched C₃₆-dicarboxylic acids. Characteristic spectroscopic and GC-data of the structural types are reported.     

Die katalytische Metathese von ungesättigten Fettsäureestern

Catalytic Metathesis of Esters of Unsaturated Fatty Acids Several active and selective catalysts have been developed for the metathesis of unsaturated hydrocarbons in homogeneous medium. These are based on WCl₆ and MoCl₅ with Sn(CH₃)₄, Sn(C₆H₅)₄ and Pb(C₆H₆)₄ as the most important co-catalysts. These catalyst systems also permit the metathesis of compounds having functional groups, such as esters of fatty acids and halogenated hydrocarbons. The metathesis of esters of fatty acids enables the synthesis of numerous compounds, which so far were either unknown or difficult to synthesize. Such compounds are, for instance, certain long chain unsaturated dicarboxylic acids which are derived from monoenoic fatty acids, such as oleic acid and erucic acid. From technological viewpoint the unsaturated dicarboxylic acids might be significant as raw material for the preparation of unsaturated polyesters and polyamides, as well as for the synthesis of certain flavoring agents. The metathesis of fatty oils (glycerides) leads to the formation of high molecular weight compounds. The metathesis of semi-drying and drying oils offers the possibility to prepare stand oils having good drying properties.     

Chain extension reactions of unsaturated polyesters with bis(2‐oxazoline)s

Two different bisoxazolines, 2,2′‐(1,3‐phenylene) bis(2‐oxazoline) (1,3‐PBO) and 2,2′‐bis(2‐oxazoline) (BO) were investigated as chain extenders for short chain unsaturated polyesters (UPEs). These extenders reacted readily with carboxyl ends of unsaturated polyesters, leading to rapid molecular weight increase through coupling of oligomeric chains. Commercially available unsaturated polyesters commonly have molecular weights around 1500, usually reached after a 20‐h polyesterification reaction. When bisoxazolines were reacted with short UPE chains obtained at the 6th hour of a commercial polyesterification reaction, the molecular weight of UPE reached 1500 within 5–30 min, which provides economies and prevents the glycol loss and yellowing which are associated with extended reaction times. Styrene solubility, gel time, and thermal and mechanical properties of the chain extended polyesters remained comparable to the commercial UPE, with 8–10 min of gel time and a storage modulus about 3000 MPa. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Polymers based on divalent metal salts of mono(hydroxyethyl) phthalate—a review

Divalent metal salts of mono(hydroxyethyl) phthalate are useful starting materials for synthesis of ionic polymers into which metal is firmly incorporated. This article surveys a series of polymers that have been synthesized by using metal salts. The salts can react with compounds having functional groups capable of reacting with hydroxyl groups. By polyaddition reactions of the salt-diol with diisocyanates in dimethylformamide, metal-containing polyurethanes, polyurethane-ureas, and isocyanurate-type crosslinked polyurethanes are obtained. In polycondensation reactions of the salt-diols with anhydrides, some systems give unsaturated polyesters soluble in styrene. Meanwhile, polyaddition reactions of systems of the salt-anhydride-epoxide give metal-containing polyesters containing ionic links in the main chain. The metal carboxylate groups of the salts catalyze the reactions in this case. The reactions have offered a commercially favorable synthetic route. Through the proper selection of components, various types of metal-containing unsaturated polyesters, cured resins, and cured rubbers are obtained. The effect of introducing metal on their physical and other properties results, and, in addition, generally Mg is more effective than Ca in improving the properties of the polymers.     

Preparation of an acrylics‐grafted polyester and its aqueous dispersion—mechanical properties of acrylics‐grafted polyesters

Mechanical properties of grafted polyesters were discussed. In the case of grafting of acrylics of more than 25% in the grafting product, mechanical properties of the grafting products decreased greatly compared with the raw polyester. The influence of the molecular structure of the grafted polyester was not observed. The effect of composition of the grafted polymers was discussed. Mechanical properties varied with the composition of the side chain. In the case of grafting onto aromatic polyesters, grafting of an aromatic unsaturated monomer improved the mechanical properties of the grafted polymer. On the other hand, in the case of grafting onto an aliphatic polyester, grafting of an aliphatic unsaturated monomer improved mechanical properties of the grafting polymer. We found that the grafting of the polymer having a high compatibility with the polyester improved the mechanical properties of the grafting products, from the determination of the compatibility of each polymer and the mechanical properties of the grafting products. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1149–1157, 2000     

Preparation and characterization of water‐extended polyester based on recycled poly(ethylene terephthalate)

An unsaturated polyester resin was prepared that was based on the reaction of oligomers obtained from the depolymerization of poly(ethylene terephthalate) waste products, with both maleic anhydride and sebacic acid. The structure of the produced polyester was compared with that prepared from the reaction of dimethyl terephthalate with both maleic anhydride and sebacic acid with IR and NMR spectroscopy. Water‐extended polyester resins were prepared from these two polyesters through curing with styrene in the presence of various amounts of water with benzoyl peroxide as an initiator. The mechanical properties of the prepared water‐extended polyesters, as well as scanning electron microscopy, were investigated. The use of water‐extended polyesters based on recycled poly(ethylene terephthalate) waste for the preparation of decorative art objects and statues was investigated. Therefore, three pharaonic statues representing Tutankhamen, Nefertiti, and a black head of a cat were prepared. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3693–3699, 2003     

Effect of composition and polyesterification catalysts on the optical properties of cured polyesters

Unsaturated polyesters based on ethylene glycol have been synthesized using a variety of anhydride, saturated and unsaturated dicarboxylic acids and various catalysts. The structure of the polyesters and the effect of the different compositions on the colour of cured polyesters are studied by FTIR, DSC and colorimetry. The structure of cured polyesters greatly depends on the isomerization of maleic acid to fumaric acid during polyesterification. The colour of unsaturated polyesters cured with the most common curing system (MEKP as initiator and CoNp as accelerator) is firstly influenced by the curing accelerator CoNp via the d–d transitions of the transition metal cobalt. Secondly, the composition of the dicarboxylic acids and anhydride used in the polyesterification influences the colour of the polyesters which depends especially on the isomerization of maleic acid. The cured maleate polyesters have more unreacted double bonds and more polar structure because of the presence of carbonyl groups, compared to the corresponding fumarate polyesters, and this structure affects the colour. The residual catalysts from the polyesterification have minor influence on the colour of cured polyesters. Copyright © 2002 Society of Chemical Industry     

Study of the behavior of polyester concretes containing ionomers as curing agents

Polyester concretes have been used in constructions for more than 20 years. This type of polymer concrete can advantageously replace traditional Portland concrete in situations that require fast consolidation of the material. Otherwise, polyester concretes are usually more expensive than Portland concretes. Part of the high cost of the polyester concretes is due to the fact that the aggregates used in the formulation of the concretes need to be dried prior to their incorporation into the polymer matrix. In this work, the use of different curing systems (methacrylic acid and maleic anhydride) was investigated to test the hypothesis that the introduction of acid functionalities into unsaturated polyesters based on isophthalic acid could both restrict the detrimental effect of moisture in the curing process and also improve interfacial interactions even in polyester concretes containing wet aggregates. In this work, as there was no search for ways to reduce cost of polyester concretes and also to contribute to the environmental preservation, unsaturated polyesters were synthesized from PET bottles and tested in the fabrication of concretes by reacting them with a conventional curing agent (styrene). Gel permeation chromatography, infrared spectroscopy, and electron microscopy were used to monitor and analyze the production of unsaturated polyester resins and concretes. Mechanical properties were also evaluated by compression tests. Results showed that methacrylic acid and maleic anhydride, when used as curing agents, led to the production of polyester concretes having higher mechanical properties in both dry and wet states than conventional polyester (based on isophthalic acid) concretes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of some novel unsaturated polyester resins containing amide groups

Summary An ethylenically dibasic acid amide was prepared by reacting anthranilic acid with maleic anhydride and characterized by various methods. The unsaturated dibasic acid amide was used for preparing three novel unsaturated polyesters with ethylene glycol (EG), diethylene glycol (DG) and tetraethylene glycol (TG), respectively. The molecular weights of the prepared polyesters were determined by the end group analysis. These polyesters were diluted with styrene / acrylonitrile (AN) mixture to prepare curable resins with inhibited premature gelation. The effect of the structure of the resins on their curing behavior and mechanical properties has been investigated.     

Cure behavior of unsaturated polyester/modified montmorillonite nanocomposites

Dynamic rheology, differential scanning calorimetry and in situ Fourier transform infrared spectroscopy were used to study the cure behavior of unsaturated polyester/modified montmorillonite nanocomposites. The results showed that their gel times increased markedly at the same cure temperature, and that the activation energy of the nanocomposites was higher than that of the pure unsaturated polyester. Their peak temperatures of enthalpy increased as well. The total exotherm of the cure reaction declined and the cure rate decreased. In the curing process of pure unsaturated polyesters, the conversion of styrene was higher than that of the double bonds on unsaturated polyester macromolecular chains. The cure mechanism of the unsaturated polyester/modified montmorillonite changed because of the presence of double bonds in the layers of modified montmorillonite. However, the conversion of styrene in the nanocomposites was lower than that of double bonds on unsaturated polyester chains during cure at room temperature, and the conversion of styrene was increased after post‐curing and was higher than that of the double bonds on unsaturated polyester chains at the end of the cure reaction. Moreover, the degree of reaction of double bonds on unsaturated polyester chains of the nanocomposites was higher than that of unsaturated polyesters. Copyright © 2006 Society of Chemical Industry     

1,4:3,6-Dianhydrohexite als Bausteine für Polymere

Polymers from 1,4:3,6-Dianhydrosorbitol 1,4:3,6-Dianhydrosorbitol and several similar dioles are easily accessible by technical processes. They can be used for the the synthesis of high molecular polyesters, polyurethanes and polycarbonates. The thermal and mechanical properties of the obtained polymers are similar to that of the respective polymers obtained from usual petrochemical raw materials. Also unsaturated polyesters can be prepared and cured by usual methods. Some of the investigated aliphatic polyesters are suitable as polymeric plasticizers for polyvinylchloride. In conclusion, it is therefore possible to replace well known dioles on petrochemical basis by monomers which can be obtained from renewable sources like starch.     

DSC curing study of catalytically synthesized maleic‐acid‐based unsaturated polyesters

Unsaturated polyesters were synthesized based on ethylene glycol and maleic acid as unsaturated dicarboxylic acid, using a variety of saturated acids in the initial acid mixture, without or with different catalysts. The curing of the polyesters produced with styrene was studied using differential scanning calorimetry (DSC) under dynamic‐ and isothermal‐heating conditions. The FTIR spectra of the initial polyesters and cured polyesters were also determined. Curing is not complete at the end of DSC scan and the unreacted bonds were quantitatively determined from the FTIR spectra and by estimation based on literature data. The value of the mean degree of conversion (α) of all double bonds (styrene unit and maleate unit) was approximately α = 0.40. Using an appropriate kinetic model for the curing exotherm of polyesters, the activation energy (E_a), the reaction order (x) and the frequency factor (k_o) were determined. Because the kinetic parameters (ie E_a, k, x) affect the kinetics in various different ways, the curves of degree of conversion versus time at various isothermal conditions are more useful to compare and characterize the curing of polyesters. The kinetic parameters are mainly influenced by the proportion of maleic acid in the polyesterification reaction mixture and secondarily by the residual polyesterification catalyst. The degree of conversion of already crosslinked polyesters is greatly increased by post‐curing them at elevated temperature and for a prolonged time. © 2002 Society of Chemical Industry     

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.     

不饱和脂肪族聚酯生物降解性的研究

以1，4-反丁烯二酸和一缩二乙二醇（DEG）为原料，采用缩聚法合成端羟基不饱和聚酯，并采用红外光谱分析（FT—IR）、羟值、酸值、黏度等对所得聚合物进行表征，确认了其分子结构．对其降解性进行研究，并且与1，4-丁二酸与一缩二乙二醇合成的饱和脂肪族聚酯进行了对比。研究结果表明，不饱和脂肪族聚酯和饱和脂肪族聚酯的生物降解性差别不大，也就是双键的引入对其生物降解性没有大的影响；但是不饱和脂肪族聚酯膜经过高温处理后，双键会打开发生交联，而交联后的不饱和脂肪族聚酯的生物降解性变差，而且交联度越高，生物降解性越差。