Synthesis and characterization of fumarate-based polyesters for use in bioresorbable bone cement composites

Fumarate-based polyesters were prepared by the transesterification polycondensation of diethyl fumarate and diols: (±)-1,2-propanediol, (S)-(+)-1,2-propanediol, 2-methyl-1,3-propanediol, and 2,2-dimethyl-1,3-propanediol. Different polyester microstructures were observed by ¹H-NMR and ¹³C-NMR spectroscopy when the reaction was conducted in the presence of p-toluenesulfonic acid monohydrate or metal containing catalysts—aluminum trichloride, titanium tetrachloride, titanium tetrabutoxide, and zinc chloride. The extent of formation of branched structures associated with hydroxyl end groups' addition to the unsaturated polyester double bonds depends on the acidity of the catalyst. The bone cement composites were prepared by mixing the fumarate polyesters with an inorganic filler, CaSO₄ · 2H₂O, and N-vinyl pyrrolidone, which crosslinks on the addition of a radical initiator, benzoyl peroxide, at ambient temperatures. The compressive strength and hydrolytic stability of the cement compositions was correlated with structure of the polyesters. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1123–1137, 1997     

Linking of oligoesters hydrolysis to polyurethane coatings

The hydrolytic stability of a series of oligoesters comprised of three and four different monomers was evaluated. The hydroxyl terminal oligoesters were prepared from adipic acid (AA) and isophthalic acid (IPA), with six different diols and one triol, which included: 1,4‐butanediol, 1,5‐pentanediol, 1,6‐hexanediol, neopentyl glycol, 2‐methyl‐1,3‐propanediol, trimethylolpropane, and 2‐butene‐1,4‐diol. The hydroxyl terminated oligoesters were reacted with phenyl isocyanate to form telechelic urethane groups. Hydrolysis rate constants were obtained from plots of acid number vs. time. It was observed that ternary oligoester systems had lower hydrolysis rates than quaternary systems. In addition to investigating the hydrolytic stability of the synthesized oligoesters, polyurethane coatings were produced by reacting the hydroxyl‐terminated oligoesters with an aliphatic polyisocyanate (1,6‐hexanediisocyanate trimer). Model oliogester hydrolysis was then correlated to the weatherability of a crosslinked polyurethane film. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40198.     

Cycloaliphatic polyester based high solids polyurethane coatings: I. The effect of difunctional alcohols

High-solids polyesters were synthesized with two cycloaliphatic diacids, 1,4- cyclohexanedicarboxylic acid (1,4-CHDA) and 1,3-cyclohexanedicarboxylic acid (1,3-CHDA); and with five diols, 1,4-cyclohexanedimethanol (CHDM), neopentyl glycol (NPG), hydroxypivalyl hydroxypivalate (HPHP), 2-butyl-2-ethyl-1, 3-propanediol (BEPD), and 1,6-hexanediol (HD). The viscosity of the polyesters was dependent on the structures of diols. The viscosity of polyesters is lower with the diol HD, intermediate with BEPD and HPHP, and higher with the diols CHDM and NPG. The polyesters were crosslinked with hexamethylene diisocyanate isocyanurate (HDI isocyanurate) affording polyurethane coatings. The mechanical properties, tensile properties, fracture toughness, and viscoelastic properties were investigated for the polyurethane films with five different diols. The cyclohexyl structure of the CHDM provides the polyurethane with rigidity which is manifested in high tensile modulus, hardness, and fracture toughness. In contrast, the linear diol, 1,6-hexanediol provides polyurethane with very high flexibility, but these coatings suffer with respect to low hardness and tensile modulus. Polymers and Coatings Department, Fargo, ND 58105. 3401 Grays Ferry Avenue, Philadelphia, PA 19146.     

Synthesis and properties of hydrophilic polymers. Part 7. Preparation,characterization and metal complexation of carboxy-functional polyesters based on poly(ethylene glycol)

Novel water-soluble polyesters with pendant carboxylic groups were synthesized by polycondensation of ethylenediaminetetra-acetic acid (EDTA) dianhydride and diethylenetriaminepenta-acetic acid (DTPA) dianhydride with poly(ethylene glycol)s of different chain-lengths. Two experimental approaches (polycondensation using various solvents and in the melt) were studied, and melt condensation was found to give higher yields of polyesters. The polymeric products were soluble in water, acetone, chloroform and toluene, and were characterized by elemental analysis, IR and NMR spectroscopy. In addition, the carboxyl functionalities were determined by titration and the hydrolytic stability studied as a function of pH. The complexing capacity of the functional polyesters was determined in dependence of pH for copper in aqueous solution using the Liquid-Phase Polymer-Based Retention (LPR) technique and found to be 257 mg g⁻¹ for the EDTA-based copolymer at pH 5 and 230 mg g⁻¹ for the DTPA-based copolymer, respectively. © 1999 Society of Chemical Industry     

Chlorination of polyesters

By photochemical chlorination chlorine was substituted on the gem-dimethyl groups of the polyterephthalate and polycarbonate of 2,2,4,4-tetramethyl-1,3-cyclobutanediol, the polyterephthalate of 2,2-dimethyl-1,3-propanediol, and the polycarbonate of 4,4′-isopropylidenediphenol (bisphenol A). The factors affecting polyester degradation, the efficiency of chlorination, and the degree of chlorination were investigated, and the effects of chlorine content on the solubility, flammability, density, hydrolytic stability, thermal stability, tensile properties, electrical properties, and heat-distortion temperatures of cast films were determined. The chlorinated polyesters of particular interest, because of their properties, are the polycarbonates of 2,2,4,4-tetramethyl-1,3-cyclobutanediol and bisphenol A.     

Equilibrium acid concentrations in hydrolyzed polyesters and polyester–polyurethane elastomers

Equilibrium acid concentrations, [A_e], were determined in butylene adipate and caprolactone polyesters, of low molecular weight, and in thermoplastic polyurethane elastomers based on these polyesters. Values of [A_e] of the polyesters at 85°C were 0.7, 1.3, and 3-4 × 10^?3 mol/g at relative humidities (RH) of 25%, 50%, and 93%, respectively. [A_e] of the thermoplastic elastomers at 85°C were about 3 and 7 × 10^?4 mol/g at 10% and 25% RH, respectively. Values of [A_e] were not very dependent on temperature at constant RH. Equilibrated thermoplastic elastomers had low molecular weights and poor physical properties. Consequently, equilibration does not set a practical limit on hydrolytic degradation, even at low RH. Equations were developed that described the variation in acid content with time. Rate constants for hydrolysis and esterification increased as RH decreased. Reesterification in the elastomers in the absence of water is too slow to be a useful method of decreasing hydrolytic damage.     

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.     

Metabolism of naphthenic hydrocarbons. Utilization of a monocyclic paraffin,dodecylcyclohexane, by rat

³H-Dodecylcyclohexane was incorporated in rat diet in order to study the metabolic utilization by mammals of a monocycloparaffin chosen as a typical naphthenic constituent of mineral oils. Dodecylcyclohexane was largely absorbed. No elimination of the hydrocabon was observed in urine while an extended excretion of³H occurred via this route. About 7% of absorbed dodecylcyclohexane was stored in the carcass, while the rest was ω-oxidized to cyclohexyldodecanoic acid, which incorporated into neutral lipids and phospholipids. The aliphatic chain of this unusual fatty acid underwent the normal fatty acid degradation pathways, leading to even fatty acids, squalene, cholesterol and nonlipid resynthesis, while the cyclohexyl ring was eliminated as urinary metabolites. Incorporation of ω-cyclohexyl fatty acids in phospholipids may raise a point of toxicological significance which is to be investigated.     

含侧基聚酯型聚氨酯耐水解性的研究

通过对比4种含有不同侧基结构的聚氨酯胶膜的力学性能和耐水解性,发现以含有较大空间位阻侧基的2-乙基-1,3-己二醇与己二酸合成聚酯二元醇（PEPO。EHO）为原料制备的聚氨酯胶膜具有较优异的耐水解性,而以1,3-丙二醇与己二酸合成聚酯二元醇（PEPO—PPD）为原料制备的聚氨酯胶膜具有较好的力学性能。选取PEPO-EHO与PEPO-PPD混合后制备出的聚氨酯胶膜力学性能和耐水解性较好。当PEPO-EHO与PEPO-PPD在软段中混合的质量分数分别为50％时,所制备的聚氨酯胶膜具有较好的综合性能。     

Synthesis and self-assembly of hyperbranched polyester peripherally modified by touluene-4-sulfonyl groups

In this paper, hyperbranched polyesters (HPs) were synthesized in the molten state from 2,2-bis(hydroxymethyl) propionic acid (bis-MPA) and 2-ethyl-2-hydroxymethyl-1,3-propanediol (TMP) using acid catalysis. The modified hyperbranched polyesters were obtained through the chemical modification of the hyperbranched polyester cores by substituting a controlled fraction of the terminal hydroxyl groups with touluene-4-sulfonyl chloride using triethylamine (TEA) as an acceptor of HCl. The resultant polyesters were characterized by ¹H NMR, ¹³C NMR, FT-IR, UV and GPC and their self-assembly behaviors were investigated. The results revealed that self-assembled structures could be formed in selected solvents (trichloromethane/acetone or trichloromethane/n-hexane).     

PTA法易水解聚酯的合成及水解性能

用精对苯二甲酸法合成了一系列易水解聚酯(EHDPET)，重点考察了共聚酯的化学结构和碱水解过程中各工艺条件对其水解性能的影响，并对EHDPET的碱水解动力学进行了初步探讨。结果表明，提高间苯二甲酸乙二酯—5—磺酸钠、第四单体等各组分含量及添加助剂可提高减量率；加大碱浓度、提高温度及延长水解时间均可加快碱水解速率。     

Preparation of biobased poly(propylene 2,5-furandicarboxylate) fibers: Mechanical,thermal and hydrolytic degradation properties

In this work, a fully biobased poly(propylene 2,5-furandicarboxylate) (PPF) was synthesized from 2,5-furan dicarboxylic acid (FDCA) and 1,3-propanediol (1,3-PDO) via traditional two-step melting polycondensation. Then, the resultant PPF was characterized with ¹H NMR, FTIR, GPC, intrinsic viscosity, TGA, and DSC measurements, respectively. Next, the prepared PPF was melt-spun into fibers. The morphology and thermal stability of the as-spun PPF fibers were firstly investigated by SEM and TGA. Furthermore, the mechanical properties of the PPF fibers were evaluated. The results showed that the tensile of the PPF fibers increased with increasing of the draw ratios following gradual decrease of the breaking elongation from 307.1% to 48.9%. In addition, the crystallization ability and the hydrolytic degradation behavior of the as-spun PPF fibers were investigated in detail as well. The results presented that comparing to traditional fossil-based poly(trimethylene terephthalate) (PTT) fibers, the PPF fibers exhibited lower crystallinity, however, it displayed a better hydrolytic degradation performance. Based on these results, it confirmed that the PPF fiber based on biomass polymer is a kind of promising environmentally friendly synthetic fiber for potential application in various fields.     

The effect of annealing on tensile properties of injection molded biopolyesters based on 2,5-furandicarboxylic acid

In this study, we investigate four polyesters based on 2,5-furandicarboxylic acid and different diols including 1,2-ethylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, and 1,6-hexylene glycol. Poly(ethylene 2,5-furanoate), poly(propylene 2,5-furanoate), poly(butylene 2,5-furanoate), and poly(hexylene 2,5-furanoate) (PHF) were characterized by thermogravimetric analysis, X-ray diffraction, differential scanning calorimeter, and tensile tests. In addition, the influence of annealing polyesters on their thermal and mechanical properties was investigated. For these reasons samples for the tensile test were prepared by injection molding. The tensile properties of injection molded samples were compared with samples that were additionally annealed after injection molding. All studied polyesters after heating treatment showed multiple melting behavior. The increase in the degree of crystallinity significantly influenced also the mechanical properties of the samples. It was found that the length of the aliphatic chain and degree of crystallinity plays a major role in the final properties of furan-based polyesters.     

NMR study of the stabilities of urea–formaldehyde resin components toward hydrolytic treatments

The solid residues of nine urea–formaldehyde (UF) resins after hydrolytic treatment at pH4 and 86°C for 20 h and the solid residues of one UF resin after eight different hydrolytic treatments were examined by ¹³C-CP–MAS NMR. The relative stability toward hydrolysis of each structural component in each UF resin was established for various hydrolytic conditions. In general, UF resins prepared from starting mixtures with a formal F/U molar ratio of 1.00 show a high degree of stability toward hydrolysis. Cross-linking methylene linkages in the UF resins show a higher susceptibility to hydrolytic treatments at pH 4 and 86°C than do linear methylene linkages. UF resins prepared with an F/U molar ratio of 2.00 are susceptible to hydrolysis at pH 4 and 86°C. Dimethylene ether linkages, methylols attached to tertiary amides, and poly(oxymethylene glycol) moieties are probably the main formaldehyde emitters in UF resin products. © 1994 John Wiley & Sons, Inc.     

Synthesis and characterization of cyclohexyl-containing poly(ether ketone sulfone)s

A series of poly(ether ketone sulfone)s were synthesized from 1,4-di(fluorobenzoyl)cyclohexane, difluorodiphenylsulfone and bisphenol A. These polymers were characterized by NMR, IR, SEC, DSC, TGA, tensile tests and DMA. The results from NMR, IR, and SEC indicated that essentially no side reactions, such as cross-linking, associated with enolate chemistry take place during the polymerizations although cis/trans stereochemistry inversion was observed. Comparison of the T_gs of the polymers with 1,4-cyclohexyl units to those of the terephthaloyl analogs suggested that the trans-1,4-cyclohexyl imparts slightly higher T_g than the terephthaloyl control. Tensile tests and DMA revealed that polymers with 1,4-cyclohexyl have essentially the same storage moduli as the corresponding aromatic analogs despite the inherent flexibility of the cyclohexyl unit. DMA also showed that the cyclohexyl unit imparts a larger magnitude of sub-T_g motion than terephthaloyl unit while maintaining high modulus.     

Protein hydrolysis under anaerobic,saline conditions in presence of acetic acid

The hydrolysis of soluble proteins in an anaerobic, saline (24 g dm^?3 NaCl) and mesophilic (37 °C) environment was studied. The inhibitory effect of a volatile fatty acid, acetic acid (HAc), on the hydrolysis rate and hydrolytic biomass activity for a model saline wastewater with a high protein load (total organic carbon, 1153 mg dm^?3 and 1572 mg dm^?3 proteins) was studied. Initial inhibitor concentrations were tested in the range of 0–2000 mg dm^?3 HAc. The microbiological characterization was performed using a total microorganism count by epifluorescence, and hydrolytic bacterial activity was determined by plate count. The protein hydrolysis was modeled according to first order kinetics. The effect of biomass on hydrolysis was analyzed by varying its concentration in the range of 42–210 mg dm^?3 volatile suspended solids. The following apparent hydrolysis kinetic constants (K_h) for proteins at 37 °C were obtained: 1.3, 0.8, 0.6, 0.2 and 0.1 d^?1 for initial concentrations of 250, 500, 750, 880, and 1000 mg dm^?3 HAc, respectively. At concentrations of HAc greater than 1000 mg dm^?3, total inhibition of hydrolysis was observed. The intrinsic hydrolysis constant ( ) at 37 °C, without inhibition, was 2.3 d^?1. The hydrolysis kinetic constant was not affected by the biomass concentration. The hydrolysis kinetics constant was filted to three models: Luong, Levenspiel and non‐competitive inhibition. The model that best represented the experimental data was Luong, obtaining an inhibition constant (K_I) of 1087 mg dm^?3 of HAc and the exponent γ = 0.54. The hydrolysis was inhibited by the presence of HAc, which corresponds to an intermediate compound of the anaerobic process. Copyright © 2004 Society of Chemical Industry     

Saturated and unsaturated polyesters based on 1,3-(dicarboxymethoxy)benzene

Saturated polyesters were prepared by the reaction of 1,3-(dicarboxymethoxy)benzene with ethylene, diethylene, tetramethylene, and hexamethylene glycols. Also, unsaturated polyesters were prepared by the reaction of 1,3-(dicarboxymethoxy)benzene and maleic anhydride with the same glycols. All the polyester resins obtained have been characterized, and the unsatureated polyesters were found to cure with styrene. The properties of the cured polyesters in the form of films were determined. IR and ¹H-NMR spectroscopy were used for both qualitative and quantitative analyses of the polyesters as well as their hydrolyzate products, after curing with styrene.     

Biologisch abbaubare Polyester-Copolymere aus petrochemischen und nachwachsenden Rohstoffen

Biological Degradable Polyester Copolymers from Petrochemical and Renewable Raw Material. Synthetic, biodegradable aliphatic polyesters often do not provide optimal properties of application (e.g. melting point of polycaprolactone: 60°C). Material properties of such polyesters can be improved by introducing aromatic compounds into polymers. It could be shown that random aliphatic/aromatic copolyesters consisting of components like 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, adipic acid, sebacic acid and terephthalic acid (35–55 mol-% with regard to the diacid components) exhibit melting points of up to 145°C. These copolyesters are still biodegradable making this material of great commercial interest. Significant weight losses of polyester films could be observed in three months soil burial experiments(up to 40mol-% terephthalic acid) and in compost simulation tests at 60°C (up to 50 mol-% terephthalic acid). From degradation experiments with aromatic model oligoesters from terephthalic acid and 1,2-ethanediol (1,3-propanediol, 1,4-butanediol, respectively) it could be concluded that, aromatic intermediates (oligomers) will be assimilated very fast by microorganisms, if the degree of polymerization is one or two. It seems that longer oligomers are not accessable for an enzymatic attack, but will probably be hydrolyzed chemically at elevated temperatures (60°C), too. Using especially screened thermophilic microorganisms (55°C) on agar plates and analysis of residual material by size exclusion chromatography, the above mentioned finding could be confirmed. Some of the components of polyesters, described here can be obtained from renewable resources. For instance. 1,3-propanediol can by produced by a fermentation process from glycerol and a number of aliphatic dicarboxylic acids are available from natural oils. This option can make biodegradable high-tech polyesters with a defined structure part of natural cycles.     

Organic acids catalyzed polymerization of ε‐caprolactone: Synthesis and characterization

Environmentally friendly organocatalytic synthesis of aliphatic polyesters was studied. The catalysis investigated is novel, and lends itself well to the potential production of valuable biodegradable products. The reactions were based on an organic acids‐catalyzed ring‐opening polymerization of ε‐caprolactone with fatty acid derivatives as the initiator and were performed in the absence of solvents. The chemical structures of the functionalized polymers were confirmed by ¹H and ¹³C‐NMR spectra. Polymers with different molecular weights, in the range 10,900–15,200 were obtained in the presence of fumaric acid as catalyst. The thermal properties of the functionalized PCLs were determined by modulated differential scanning calorimetry and thermogravimetric analysis. The MDSC results verified that the crystallinity and the melting point of the lipid‐functionalized polymers were lower than that of the unfunctionalized poly(ε‐caprolactone). The hydrolytic degradation of the functionalized polymer was also investigated. The result shows the degradation rate was affected by the presence of oleic acid derivatives in the polymer molecule. The lipid‐functionalized polymers synthesized by the metal‐free polymerization systems seem to be suitable biodegradable polyesters for use in biomedical and pharmacological applications. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis,characterization, and stability of poly[(alkylene oxide) ester] thermoplastic elastomers

Poly(ether ester) block copolymers were prepared using a transesterification/polycondensation bulk synthesis with systematic control of the terephthalic acid/butane-diol aromatic diester block (`hard segment') and with poly(tetramethylene oxide) [PTMO], poly(hexamethylene oxide) [PHMO], or poly(decamethylene oxide) [PDMO] poly(alkylene oxide) soft segments. The respective number average molecular weights were 980, 930, and 940 Da. A series of the poly(ether ester)s with hard segment fractions of 25, 29, 37, and 51% were prepared. One example of the PDMO polyester was prepared at a 51% hard segment fraction. The polyesters were characterized using viscometry, gel permeation chromatography, ¹H-NMR spectroscopy, differential scanning calorimetry, and tensile testing. The novel poly(ether ester)s, the PTMO polyester, and the commercial control, Hytrel® 4056, were compared for their resistance to degradation in a 50% aqueous hydrogen peroxide solution at 37°C, boiling water buffered at pH 1 and 13, an oxygen stream at 200°C, and a nitrogen stream at 200°C. The Hytrel® 4056 and the PTMO polyesters fragmented in hydrogen peroxide within 24 h while the PHMO and PDMO polyesters were much less degraded. Resistance to hydrolytic and thermal degradation increased as the ratio of aliphatic methylene to ether increased: PTMO < PHMO < PDMO. Samples containing higher hard segment fractions demonstrated improved resistance to hydrolysis. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1319–1332, 1997