Unsaturated Copolyesters Research Articles

Collagen-decorated electrospun scaffolds of unsaturated copolyesters for bone tissue regeneration.

Many efforts have been devoted to bone tissue to regenerate damaged tissues, and the development of new biocompatible materials that match the biological, mechanical, and chemical features required for this application is crucial. Herein, a collagen-decorated scaffold was prepared via electrospinning using a synthesized unsaturated copolyester (poly(globalide-co-pentadecalactone)), followed by two coupling reactions: thiol-ene functionalization with cysteine and further conjugation via EDC/NHS chemistry with collagen, aiming to design a bone tissue regeneration device with improved hydrophilicity and cell viability. Comonomer ratios were varied, affecting the copolymer's thermal and chemical properties and highlighting the tunable features of this copolyester. Functionalization with cysteine created new carboxyl and amine groups needed for bioconjugation with collagen, which is responsible for providing biological and structural integrity to the extra-cellular matrix. Bioconjugation with collagen turned the scaffold highly hydrophilic, decreasing its contact angle from 107 ± 2° to 0°, decreasing the copolymer crystallinity by 71%, and improving cell viability by 85% compared with the raw scaffold, thus promoting cell growth and proliferation. The highly efficient and biosafe strategy to conjugate polymers and proteins created a promising device for bone repair in tissue engineering.

Synthesis and structure design of novel unsaturated copolyesters based on indazole moiety in the main chain with good thermal stability for catalytic activity and anti-corrosion applications

Novel unsaturated polyesters based on indazole moiety in the main chain are prepared by interfacial polycondensation of two different indazoline monomers with an acid chloride. The producing copolyesters were confirmed and described by different techniques including Fourier-transform infrared spectroscopy (FTIR), and proton nuclear magnetic resonance (1H-NMR). Their crystallinity and thermal stability are measured through X-ray powder (XRD) and thermogravimetric analysis (TGA) and show that they have good thermal stability which is affected by their crystallinity. The morphological features of the synthesized copolyesters were tested by scanning electron microscopy (SEM). Moreover, the resulting copolyesters were intended to be utilized as a catalyst in the preparation of polysubstituted imidazoles produced by three-component ammonium, and acetate 1,2-diketone with an aldehyde under mild conditions. The corrosion mitigation features of the fabricated unsaturated copolyesters as inhibitors for mild steel corrosion in molar hydrochloric acid were investigated. The unsaturated copolyesters exhibited respectable inhibition characteristics owing to robust adsorption on the metal interface and the construction of a defensive layer. The maximum protection capacity values ranged from 94.87 to 98.41% in the presence of 100 ppm of copolyesters. Adsorption of the unsaturated polyesters followed the Langmuir isotherm. Potentiodynamic polarization (PDP) examinations showed that the studied unsaturated polyesters were mixed-kind inhibitors.

Unsaturated Copolyesters from Macrolactone/Norbornene: Toward Reaction Kinetics of Metathesis Copolymerization Using Ruthenium Carbene Catalysts

Unsaturated copolyesters are of great interest in polymer science due to their broad potential applications and sustainability. Copolyesters were synthesized from the ring-opening metathesis copolymerization of ω-6-hexadecenlactone (HDL) and norbornene (NB) using ruthenium-alkylidene [Ru(Cl2)(=CHPh)(1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)(PCy3)] (Ru1), [Ru(Cl)2(=CHPh)(PCy3)2] (Ru2), and ruthenium-vinylidene [RuCl2(=C=CH(p-C6H4CF3))(PCy3)2] (Ru3) catalysts, respectively, yielding HDL-NB copolymers with different ratios of the monomer HDL in the feed. The activity of N-heterocyclic-carbene (NHC) (Ru1) and phosphine (Ru2 and Ru3) ligands containing ruthenium-carbene catalysts were evaluated in the synthesis of copolymer HDL-NB. The catalysts Ru1 with an NHC ligand showed superior activity and stability over catalysts Ru2 and Ru3 bearing PCy3 ligands. The incorporation of the monomers in the copolymers determined by 1H-NMR spectroscopy was similar to that of the HDL-NB values in the feed. Experiments, at distinct monomer molar ratios, were carried out using the catalysts Ru1–Ru3 to determine the copolymerization reactivity constants by applying the Mayo–Lewis and Fineman–Ross methods. The copolymer distribution under equilibrium conditions was studied by the 13C NMR spectra, indicating that the copolymer HDL-NB is a gradient copolymer. The main factor determining the decrease in melting temperature is the inclusion of norbornene units, indicating that the PNB units permeate trough the HDL chains. The copolymers with different molar ratios [HDL]/[NB] have good thermal stability up to 411 °C in comparison with the homopolymer PHDL (384 °C). Further, the stress–strain measurements in tension for these copolymers depicted the appreciable increment in stress values as the NB content increases.

Trans-2-Butene-1,4-Diol as an Olefinic Building Block to Prepare Biobased Unsaturated Copolyesters with High Molecular Weight: Synthesis, Characterization, and Physical Properties

A series of biobased poly(butylene succinate-co-trans-butene succinate) (PBStBS) was prepared by copolymerizing biobased trans-2-butene-1,4-diol(tB), succinic acid, and 1,4-butanediol via a two-ste...

4D printing of shape memory aliphatic copolyester via UV-assisted FDM strategy for medical protective devices

4D printing, as a booming additive manufacturing technology of smart material, provides a new opportunity for the development of shape memory polymers (SMPs). Meanwhile, the diversity of SMPs structure calls for flexible and well-adapted printing technology. Fused deposition modelling (FDM) is one of the most versatile and cost-effective methods owing to the simplicity of the technique and broad compatibility with a wide variety of materials, but it fails to deal with the fabrication of shape memory networks that possess excellent structural stability as well as shape memory effect (SME). Aiming to personalized or patient-adaptable treatment devices, in this work, we demonstrate a UV-assisted FDM 4D printing strategy to fabricate elbow protector models based on shape memory copolyester networks. First, the linear unsaturated copolyesters were synthesized, amongst, poly(lactic acid) was chosen as hard segment providing the material a good mechanical performance and printability, the poly(ε-caprolactone) with strong crystallizability was employed as switching segment, and a functional coupling agent contained double bonds was used to join the two segments and as the same time. This copolyester can be easily processed into filament, and the in-situ formation of photo-crosslinking network during the UV-assisted FDM printing not only enhances the bonding strength of each layer, but also may guarantee the obtained objects a good shape memory property. Three models with distinctly Chinese characteristics were printed to demonstrate excellent SME. Then, the elbow protectors both in personalized and patient-adaptable treatment strategies were developed, which indicates a great potential in robust applications.

Isothermal Kinetics of Poly(butylene adipate-co-butylene itaconate) Copolyesters with Ethylenediaminetetraacetic Acid.

A series of aliphatic copolyesters, poly(butylene adipate-co-butylene itaconate) (PBABI), have been synthesized using melt polycondensation of adipic acid (AA), itaconic acid (IA), 1,4-butanediol (1,4-BDO), and the tetra-functional group of ethylenediaminetetraacetic acid (EDTA, 0.1 mol %) to form partially cross-linking density as novel thermoplastic unsaturated copolyesters in our previous research. The crystal phase of PBABI copolyesters tended to prefer thermodynamics in the presence of a small amount of EDTA. The isothermal crystallization analysis revealed that the PBABI with EDTA exhibited a higher crystallization rate and a shorter half-time of crystallization than neat PBABI copolyesters. All of the sizes of spherulite/sheet crystals in the BA/BI = 9/1 are smaller than at BA/BI = 10/0 with or without a cross-linking agent, which demonstrated that the morphology behavior tended to form a small sheet crystal in the presence of 10 mol % IA, which played a dominant role in determining the average size of the crystal. These results deepen our understanding of the relationship among the cross-linking agent, the crystal form, and solidification time in PBABI copolyesters, making these kinds of polymers applicable to reinforce three-dimensional (3D) air-permeable polyester-based smart textiles.

High Molecular Weight Unsaturated Copolyesters Derived from Fully Biobased trans-β-Hydromuconic Acid and Fumaric Acid with 1,4-Butanediol: Synthesis and Thermomechanical Properties

This work describes the synthesis, structure, and physical and thermomechanical properties of fully biobased unsaturated copolyesters via melt-polycondensation of renewable monomers trans-β-hydromuconic acid and fumaric acid with 1,4-butanediol conducted by a two-step polymerization employing stannous octoate as a catalyst and 4-methoxyphenol as a radical inhibitor. The polymerization conditions, including catalyst amount, second-stage reaction temperature, and time, were optimized to prepare high molecular mass unsaturated copolyesters without isomerization and saturation reaction in the unsaturated double bonds. Consequently, a series of poly(butylene hydromuconoate-co-butylene fumarate) (PBHBF) samples with weight-average molecular weight over 80 kg/mol were obtained. The chemical structures identified by 1H and 13C NMR indicated that the notorious side reactions of isomerization and saturation of C═C bonds in unsaturated polyesters were eliminated in the obtained PBHBF copolyesters. From the physical ...

Competition and miscibility of isodimorphism and their effects on band spherulites and mechanical properties of poly(butylene succinate-co-cis-butene succinate) unsaturated aliphatic copolyesters

Unsaturated copolyesters poly(butylene succinate-co-cis-butene succinate) (P(BS-co-cBS)) were the first time prepared by polycondensation in combination with stannous octoate as catalyst and 4-methoxyphenol as radical inhibitor, achieving linear random copolyesters with a number-average molecular weight up to 38.2 kg/mol. The cis-2-butene-1, 4-diol used in this work showed a peculiarity of no isomerization or cross-linking side reaction even at high reaction temperatures, due to the high chemical stability of the unconjugated cis-double bond. Isodimorphic behavior between butylene succinate (BS) and cis-butane succinate (cBS) in P(BS-co-cBS) was evidenced by DSC and WAXD analyses. Then, the competition and miscibility of isodimorphism between BS and cBS units were further investigated by thermodynamic analyses. The significant discrepancy in competition and miscibility between BS and cBS units from conformational geometry demonstrated unique physicochemical properties and structure-properties relationships in such system of unsaturated copolyesters. A great impact of competition and miscibility on band spherulites and mechanical properties of the copolyesters was observed and discussed. In conclusion, our work here not only clarifies the effect of cis-double bond on isodimorphism in the unsaturated copolyesters, but also gives an insight into the mechanism of how the competition and miscibility regulates their physical properties.

The Effect of Different Acid Chloride on Physical and Chemical Characterizations of Aryledinecycloalkanone Unsaturated Copolyesters

The Effect of Different Acid Chloride on Physical and Chemical Characterizations of Aryledinecycloalkanone Unsaturated Copolyesters

Facile preparation of stereochemistry-controllable biobased poly(butylene maleate-co-butylene fumarate) unsaturated copolyesters: a chemoselective polymer platform for versatile functionalization via aza-Michael addition

Biobased stereochemistry-controllable poly(butylene maleate-co-butylene fumarate) unsaturated copolyesters were facilely prepared as a chemoselective polymer platform for versatile functionalization via aza-Michael addition.

Fabrication and Characterization of Unsaturated Copolyesters Based on Diarylidenecyclohexanone

New series of unsaturated copolyesters based on diarylidenecyclohexanone, were synthesized by the interfacial polycondensation polymerization technique. Aldol condensation reaction in acid media was used for preparation of three kinds of monomers and investigated by FT IR and 1H NMR. The copolymers have been synthetized by the polymerization of 2, 6-bis (4-hydrxybenzylidene) cyclohexanone I, 2, 6-bis (3-hydroxybezylidene) cyclohexanone II, or 2, 6-bis (4-hydroxy-3-methoxybenzylidene) cyclohexanone III with isophthaloyl, terphthaloyl, adipoyl, sebacoyl and azobenzene 4, 4-dicaroxyldichloride. The resulting copolyesters were characterized by FT-IR, 1HNMR. The intrinsic viscosity of these copolyesters was used for the determination of the molecular weight. The thermal stabilities of the prepared copolyesters were evaluated thermogravimeteric analysis (TGA). Differential thermal analysis (DTA) was used for determination of glass temperatures. X–ray analysis showed that polymers have low degree of crystallinity. The morphological properties of some selected copolyesters were detected by SEM. The dielectric and electrical resistance, capacitance, inductance, demonstrating the insulator behaviour of copolymers.

Ultrasonic Mechanical, Dialectical and Morphology Characterizations of Unsaturated Copolyesters and Terpolyesters

In a previous study we focused on the synthesis of new family of unsaturated copolyesters and terpolyesters by interfacial condensation polymerization. Here, in this study as complementary work of physical characterizations, we focused on the morphological features using X-ray and SEM investigation. Further, the mechanical properties of solid polymers were also studied by a new technique echo-pulse using ultrasonic impulses. This technique was used for solid polymers to determine the elastic moduli involving, Young’s modulus, shear modulus, bulk modulus and micro-hardness modulus. The statistical relation between different kinds of copolyesters and terpolyesters with Poisson’s ratio (υ) and micro-hardness were shown. The dielectric constant (?) and the electrical resistance (Rp) of the solid copolyesters and terpolyesters including aliphatic, aromatic and azo group in the main chain have been studied at room temperature. Moreover, the relation between frequency and dielectric constant for the selective polymers has been also illustrated.

Unsaturated copolyesters of lactide

Four classes of unsaturated copolyesters of l-lactide were prepared either from isosorbide or bis(hydroxymethyl)tricyclodecane in combination with fumaric acid or from 1,4-butenediol or 1,4-butynediol with terephthalic acid.

New unsaturated copolyesters based on 2,5-furandicarboxylic acid and their crosslinked derivatives

The synthesis and characterisation of a novel family of unsaturated polyesters (UPs) and their crosslinked resins (UPRs), based on 2,5-furandicarboxylic acid (FDCA), are reported.

Synthesis, Characterization and Biological Activity of Saturated and Unsaturated Copolyesters Based on Bisphenol-A

SATURATED copolyesters were prepared by polyesterification of bisphenol-A (BPA) and phthalic anhydride or tetrabromophthalic anhydride with ethylene glycol, diethylene glycol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, and cis-2-butene-1,4-diol. Also, unsaturated copolyesters were prepared by polyesterification of bisphenol-A and maleic anhydride with the same glycols. All the copolyester resins obtained have been characterized; unsaturated copolyesters were found to cure with styrene. The properties of the copolyester in the form of films were determined. Also, the fire retardancy of polyesters was evaluated as varnish films on plywood strips. IR and 1HNMR spectroscopy were used for characterization of the copolyester resins. The antimicrobial activity of the copolyesters obtained was examined against gram-positive and gram-negative bacteria.

Synthesis of microbial elastomers based on soybean oil. Autoxidation kinetics, thermal and mechanical properties

Microbial bioelastomers prepared by the autoxidation of the unsaturated medium-long chain length co-poly-3-hydroxyalkanoate’s (mlcl-PHAs) based on soybean oily acids (Sy) have been reported. Pseudomonas oleovorans were grown on a series of the mixture of octanoic acid (OA) and Sy with the weight ratio of 20:80, 28:72 and 50:50 in order to obtain unsaturated mlcl-copolyesters coded PHO-Sy-2080, PHO-Sy-2872, and PHO-Sy-5050, respectively. The microorganism was also grown on the mixture of Sy and 10-undecenoic acid (UA) with the weight ratio of 50:50 to obtain unsaturated copolyester coded PHU-Sy-5050. The PHAs obtained were characterized by 1H NMR and GC-MS techniques. Double bond contents of the unsaturated PHAs obtained were varying between 0.8 to 20 mol %. Autoxidation of the unsaturated copolyesters were carried out on exposure to air at room temperature in order to obtain new biomaterials whose mechanical strength was improved. Autoxidation kinetics, shelf life, mechanical and thermal properties of these biomaterials were evaluated.

Increased diversification of polyhydroxyalkanoates by modification reactions for industrial and medical applications

A wide range of diverse polyhydroxyalkanoates, PHAs, is currently available due to the low substrate specificity of PHA synthases and subsequent modifications by chemical reactions. These polymers are promising materials for a number of different applications due to their biocompatibility and biodegradability. This review summarizes the large variability of PHAs regarding chemical structure and material properties that can be currently produced. In the first part, in vivo and in vitro biosynthesis processes for production of a large variety of different PHAs will be summarized with regard to obtaining saturated and unsaturated copolyesters and side chain functionalized polyesters, including brominated, hydroxylated, methyl-branched polyesters, and phenyl derivatives of polyesters. In the second part, established chemical modifications of PHAs will be summarized as that by means of grafting reactions and graft/block copolymerizations, as well as by chlorination, cross-linking, epoxidation, hydroxylation, and carboxylation, reactions yield further functionalized PHAs.

Synthesis and characterization of biodegradable poly(butylene succinate- co-butylene fumarate)s

A series of aliphatic biodegradable polyesters modified with fumaric residues was synthesized by transesterification in the melt of dimethyl succinate, dimethyl fumarate and 1,4-butanediol. The amount of unsaturation, originating from the fumaric acid residues in the polyesters chains was varied from 5 to 20 mol%. The molecular structure and composition of the polyesters were determined by 1H NMR spectroscopy. The effects of the content of fumaric residues on the thermal and thermo-oxidative properties of the synthesized polyesters were investigated using differential scanning calorimetry (DSC) and thermogravimetric analysis. The degree of crystallinity was determined by DSC and wide angle X-ray scattering. The degrees of crystallinity of the unsaturated copolyesters were reduced, while the melting temperatures were higher in comparison to poly(butylene succinate). Biodegradation of the synthesized copolyesters was estimated in enzymatic degradation tests using a buffer solution with Rhizopus arrhizus lipase at 37 °C. Although the degree of crystallinity of the copolyesters decreases slightly with increasing unsaturation, the biodegradation is not enhanced suggesting that not only the chemical structure and molecular stiffness but also the morphology of the spherulites has an influence on the biodegradation properties. The highest biodegradability was observed for the copolyesters containing 5 and 10 mol% of fumarate units.

Biodegradable polyesters based on succinic acid

Two series of aliphatic polyesters based on succinic acid were synthesized by copolymerization with adipic acid for the first series of saturated polyesters, and with fumaric acid for the second series. Polyesters were prepared starting from the corresponding dimethyl esters and 1,4-butanediol by melt transesterification in the presence of a highly effective catalyst tetra-n-butyl-titanate, Ti(0Bu)4. The molecular structure and composition of the copolyesters was determined by 1H NMR spectroscopy. The effect of copolymer composition on the physical and thermal properties of these random polyesters were investigated using differential scanning calorimetry. The degree of crystallinity was determined by DSC and wide angle X-ray. The degrees of crystallinity of the saturated and unsaturated copolyesters were generally reduced with respect to poly(butylene succinate), PBS. The melting temperatures of the saturated polyesters were lower, while the melting temperatures of the unsaturated copolyesters were higher than the melting temperature of PBS. The biodegradability of the polyesters was investigated by enzymatic degradation tests. The enzymatic degradation tests were performed in a buffer solution with Candida cylindracea lipase and for the unsaturated polyesters with Rhizopus arrhizus lipase. The extent of biodegradation was quantified as the weight loss of polyester films. Also the surface of the polyester films after degradation was observed using optical microscopy. It could be concluded that the biodegradability depended strongly on the degree of crystallinity, but also on the flexibility of the chain backbone. The highest biodegradation was observed for copolyesters containing 50 mol.% of adipic acid units, and in the series of unsaturated polyesters for copolyesters containing 5 and 10 mol.% of fumarate units. Although the degree of crystallinity of the unsaturated polyesters decreased slightly with increasing unsaturation, the biodegradation was not enhanced suggesting that not only the chemical structure and molecular stiffness but also the morphology of the spherulites influenced the biodegradation properties.

Side chain liquid crystalline elastomers II. Thermal properties and orientational behaviour of the LCE based on unsaturated copolyesters

The effect of crosslinking density on the phase behaviour of smectic liquid crystalline networks was studied; the results showed that crosslinking in their smectic phases can greatly enhance the stability of the liquid crystalline phase. The higher the crosslinking density, the higher the smectic-isotropic transition temperature. The mechanically-induced orientation was studied by polarized FTIR spectroscopy. The smectic liquid crystalline network could be oriented parallel to the mechanical field at higher draw ratio λ, while at lower λ the mesogenic groups are oriented perpendicular to the field for the networks with higher crosslinking density. The observed mechanically-induced orientation is interpreted by a proposed mechanism.