Glycol Fumarate Research Articles

Synthesis and Investigation of Catalytic Properties of Metal-Polymer Nanocomposites Based on Unsaturated Polyester Resins

This paper focuses on the hydrogenation process in metal-polymer complexes based on copolymers of polypropylene glycol fumarate phthalate and polypropylene glycol maleate phthalate, using acrylic acid and immobilized cobalt metal particles as catalysts. A classical reaction of the electrocatalytic hydrogenation of pyridine to piperidine was applied. SEM and dynamic light scattering were utilized to investigate the average size and dispersity of cobalt metal nanoparticles. The experimental findings show that the efficiency of hydrogenation can be improved by increasing the temperature from 25 to 40 °C and the current to 2 A. More specifically, increasing the temperature to 40 °C promotes swelling of the polymer and its transition from a globular collapsed state to an open one, which leads to an increase in the number of active catalytic centers and, as a consequence, acceleration of the hydrogenation process. Increasing the current strength to 2 A also helps to increase the rate of the hydrogenation process. Further increasing the current to 3 A is undesirable due to an increase in the yield of by-products and a decrease in the yield of the target product, piperidine. Based on a comparative analysis, it was established that the use of a copolymer of polypropylene glycol maleate phthalate with acrylic acid as the polymer matrix base is the most preferable for obtaining polymer-metal complexes with nanosized cobalt.

Effect of Heat Treatment on the Supramolecular Structure of Copolymers Based on Poly(propylene glycol fumarate phthalate) with Acrylic Acid

Previous studies investigating the thermal decomposition of p-PGFPh:AA copolymers in an inert atmosphere have provided only a general understanding of the changes that occur during thermolysis. Comprehensive studies are required to gain a better understanding of these processes [1]. The most comprehensive information on the influence of various factors on both the kinetics and the supramolecular structure of the resulting products can be obtained by combining the method of thermal analysis with IR, mass spectrometry, and scanning electron microscopy. The compounds studied have two different compositions, namely p‑PGFPh:AA 6.77:93.23 mol % and p-PGFPh:AA 86.67:13.33 mol %. These compounds were then subjected to a thermolysis process, which resulted in the emission of gases and a decrease in sample weight. The degradation process can be divided into three stages: 1) Depolymerization of the main chain; 2) Depolymerization of the side chain; 3) Final decomposition. These processes occur sequentially at different temperature ranges. According to TG- and DTG studies, complete decomposition of p-PGFPh:AA copolymers occurred at Tterm = 340–350 °C. In this temperature range, a slight loss of sample mass (less than 10 wt %) was observed along with a slight gas evolution. The main gaseous products from the transformation of the studied samples were CO and CO2. This was supported by IR-CO (2000–2200 cm−1) and CO2 (2310–2370 cm−1) as well as mass spectrometric observations. The final products resulting from the thermolysis of p-PGFPh:AA copolymers were examined under an electron microscope. The results showed a similar morphological pattern of mesostructures with sizes ranging from 0.3–1.5 μm, which were observed depending on the porous structure of the initial polymer material. Based on the experimental data, it can be concluded that the p-PGFPh:AA copolymers (in proportions of 6.77:93.23 mol % and 86.67:13.33 mol %) have a relatively high degree of resistance to heating and do not undergo any changes in chemical composition, particle size and shape. In conclusion, the results clearly indicate that the selection of conditions for pyrolysis plays a crucial role in increasing the thermal stability of polymeric materials. This method allows for purposeful changes in the structure and properties of polymers.

INFLUENCE OF EXTERNAL FACTORS ON BINARY SYSTEMS DURING RAFT POLYMERIZATION

The article discusses the method of radical copolymerization as an effective way to obtain new polymer compounds with practically valuable properties. This method is based on the free radical mechanism, in which the sequential addition of molecules of an unsaturated monomeric compound to a growing macroradical occurs. Due to the relative simplicity of this method, it makes it possible to produce a large number of polymers for various purposes on an industrial scale. Unsaturated polyesters of various compositions and molecular weights, which can significantly affect the properties of the final products, are considered promising coreagents capable of entering into radical copolymerization reactions with vinyl monomers. The article discusses the results of studies of polymer gels obtained on the basis of unsaturated carboxylic acids. The author refers to previous studies, showing that such gels have high sorption capacity, while the starting material does not have similar properties. The following describes the structure analysis of p-PGFPh copolymers with these acids, where important characteristics such as the presence of ionized units in vinyl monomers are discussed. The significance of these studies for the creation of materials with the necessary properties of sorption and interaction with other substances. Study of the influence of environmental pH on the behavior of copolymers based on polypropylene glycol fumarate phthalate with acrylic and methacrylic acids. The equilibrium degree of swelling of the studied copolymers in aqueous solutions at different temperatures was also determined by the gravimetric method. In general, analysis of the swelling curve when varying the acidity/alkalinity of the external solution indicates that the gels we synthesized are polyelectrolytes; analysis of the curve when exposed to temperature, the resulting copolymers are thermosensitive. Thus, the main idea of the article is the importance of using unsaturated carboxylic acids to create polymer gels with high sorption capacity and emphasizes the importance of analyzing the structure of such materials to understand their properties and application possibilities.

Synthesis of Water-Soluble Polyethylene Glycol Fumarates for Biomedical Applications

Polyethylene glycol fumarate (PEGF) with controlled structural composition has been obtained for further synthesis of double network crosslinked hydrogels for biomedical applications. The copolymer has been synthesized by polycondensation reaction of fumaric acid and polyethylene glycol (PEG-600). Molecular weight of PEGF has been determined by gel permeation chromatography to be approximately 6000 Da with gel permeation chromatography. The polycondensation of fumaric acid and PEG-600 was studied throughout the reaction process. The structure of the reaction product has been evidenced using FTIR- and 1H NMR-spectroscopy. The quantitative ratios of the amount of –C=C– bonds and –COO groups to –C=O groups in the obtained PEGF have been estimated from IR-spectra for different synthesis time. The time-dependence of molar ratio of double bonds to methyl groups in PEGF has been obtained from corresponding 1H NMR-spectra. FTIR and 1H NMR-spectroscopy, both, demonstrate that after the end of reaction the unsaturated –C=C– double bonds remain in the structure of the macromonomer, that is essential for further preparation of cross-linked hydrogels. The addition of the tightly cross-linked network of polyvinyl alcohol leads to formation of highly tough biocompatible material for preparation of the artificial meniscus which can further be used as a solution n the treatment of diseases such as osteoarthritis.

Investigation of Curing Process and Thermal Behavior of Copolymers Based on Polypropylene Glycol Fumarate and Acrylic Acid Using the Methods of DSC and TGA.

In this work, the possibility of preparation of copolymers of three-dimensional crosslinked structure based on polypropylene glycol fumarate and acrylic acid is shown. The initial reagent polypropylene glycol fumarate has been synthesized by polycondensation reaction of fumaric acid and propylene glycol. The curing process of polypropylene glycol fumarate and acrylic acid at various mole concentrations was studied using DSC method at isothermal and dynamic regimens. Curing in isothermal condition was carried out at temperatures of 60 °C, 70 °C, and 80 °C. Residual reactivity was evaluated at a dynamic regimen within the temperature range from 30 °C to 200 °C at a constant heating rate. On the basis of calorimetric studies, the thermal effects and kinetic parameters of the reaction (conversion, reaction rate, activation energy) have been determined. Thermal behavior of cured samples of p-PGF-AA was estimated using dynamic thermogravimetry (TGA). According to TGA data, the process of decomposition of the studied copolymers proceeds in several stages. Based on the results obtained, the activation energies of thermal decomposition were calculated using the iso-conversional methods of Kissinger-Akakhira-Sunose and Friedman.

Investigation of the Influence of UV-Irradiation on Thermal Stability of Binary Systems on the Basis of Polyethylene Glycol Fumarate with Some Vinyl Monomers

This work is devoted to the investigation of continuous exposure to UV-irradiation on thermal stability of polymeric base of sealants. The copolymers of polyethylene glycol fumarate with acrylic and methacrylic acids, and acrylamide of the composition of “unsaturated polyester: vinyl monomer” ~35:65 mass.% (correspondingly) were chosen as the polymer base. The samples were analyzed on microscope to the presence of microcracks as a result of exposure to UV-irradiation on them. The studied samples were evaluated visually on color change and the appearance of turbidity. Thermal stability of the studied polymeric base was determined by establishing the temperature of the start of thermal deformation by thermogravimetry before and after the process of UV-irradiation within 21 days. It was established that for the polymeric base with acrylamide in its content the temperature of the start of thermal deformation had reduced after exposure to UVirradiation. In contrary, for the polymeric bases with acrylic and methacrylic acids in their composition the above said thermal index almost had not changed after affecting with UV-irradiation on the samples.

Comparative Analysis of Thermal Decomposition Kinetics of Copolymers Based on Polyethylene Glycol Fumarate with Methacrylic Acid

The thermal properties of a copolymer based on polyethylene glycol fumarate with methacrylic acid in a nitrogen atmosphere were studied in this paper. Four various heating rates and two types of a polyester resin composition were used. The analysis of thermal decomposition kinetics was implemented. Three kinetics methods namely Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose and Friedman were applied. Curves of a thermogravimetric analysis demonstrated that the thermal decomposition of copolymers with different molar ratios was observed. It was determined that the kinetic data depends on the studied copolymers’ composition. The obtained data showed a good convergence in various heating rates. Also, the thermodynamic characteristics were calculated namely the changes in the Gibbs energy (ΔG), enthalpy (ΔH) and entropy of activation (ΔS). The Achar-Brindley-Sharp method was used to find the invariant kinetic parameters of decomposition. Thus, the the kinetic compensation effect was applied to define a reaction model and a pre-exponential factor. A main phase of the copolymer decomposition in a narrow temperature range was determined. It was attested by a peak on the differential curve. An insignificant mass loss of the volatile-matter yield was observed in the range of 30–150 °C.

Development of Energy-Efficient “Cold” Curing Method for Polypropylene Glycol Fumarate Using an Optimized Initiating System

The possibility of using the polymeric matrix obtained as a result of “cold” polymerization of polypropylene glycol fumarate (p-PGF) with methacrylic acid (MAA) as a polymeric base for obtaining new adhesives of domestic production was demonstrated. The starting reagent (p-PGF) was synthesized by condensation polymerization of fumaric acid with propylene glycol in the presence of a catalyst, which reduced the temperature and shortened the process time. A number of solutions of p-PGF in MAA of different mass compositions were obtained and their rheological properties were determined. Curing of the studied solutions was carried out by radical polymerization at room temperature in the presence of the “cold curing” initiating system. The optimum composition and amount of components of the “cold” curing initiating system consisting of an initiator (benzoyl peroxide) and a promoter (dimethylaniline) were established. Technological parameters of curing (temperature, lifetime and curing time, the value of volume shrinkage) were determined. The obtained compounds were identified by infrared spectroscopy. The surface morphology of the cured samples was studied by scanning electron microscopy. It was found that varying the composition of the initial polymermonomer mixture allows controlling the physicochemical properties.

STUDY OF THERMAL DECOMPOSITION OF THE COPOLYMER BASED ON POLYETHYLENE GLYCOL FUMARATE WITH METHACRYLIC ACID

Thermal performance of copolymer based on polyethylene glycol fumarate and methacrylic acid in a dynamic mode, in an inert nitrogen environment are considered in the present work. Kinetic evaluation of thermal decomposition process was conducted using three different data processing methods (Friedman, Ozawa-Flynn-Wall, Kissinger-Akahira-Sunose). Utilizing a mixed-method approach kinetic triplets Eа, A, g(a) were received. The received kinetic parameters were used to calculate the thermodynamic characteristics of Gibbs energy (∆G), enthalpy (∆H) and entropy of activation (∆S). Copolymer thermal gravimetric analysis (TGA) and differential thermogravimetric analysis (DTA) curves were studied under nitrogen environment using a heating rate of 2,5, 5, 10 or 20°C/min. The method of Invariant Kinetic Parameters was used to identify the reaction model and pre-exponential factor. The main phase of copolymer decomposition was set, which occurred within a narrow temperature interval and is evidenced by the spike on the differential curve. Values for 13 reaction models were received. Utilised methods resulted in a proper energy activation alignment within 223-229 kJ mol-1. Design and experimental data provided close values. TGA and DTA curve analysis has shown a sufficient thermal stability of these copolymers under the nitrogen environment.

Kinetic parameters of thermal destruction of the copolymer of polyethylene glycol fumarate with acrylic acid in inert medium

Thermal decomposition of the copolymer of polyethylene glycol fumarate with acrylic acid (p-EGF:AA) of two different compositions synthesized earlier was studied in the present work. TG and DTG curves prove that decomposition takes place in several stages. According to thermogravimetric curves it has been found out that for the copolymer with higher content of acrylic acid the decomposition of the copolymer’s sample is started at higher temperatures. It has been shown the shift of the temperature of decomposition’s start to the higher area with the increase of heating rate which is necessary for the detorsion of macromolecular coil. Experimental data processed using graphical methods of Kissinger–Akahira–Sunose and Friedman allowed us to calculate the activation energy of the thermal decomposition process. It has been established that the copolymer with the composition of 21.03:78.97 mass.% has lower meaning of activation energy than the one with the composition of 68.96:31.04 mass.%. As a result of calculation one can see that the meanings found out using these methods depend slightly on conversion. Using Achar-Brindley-Sharp method and the method of invariant kinetic parameters the kinetic triplet of the decomposition process has been found which was used to build the calculated curve. The dependences of g(α) on α using these parameters showed a satisfactory agreement of calculated curves with the experimental ones. One can conclude that the decomposition process of the copolymer of polyethylene glycol fumarate with acrylic acid is well described with of D3 (three-dimensional diffusion) model.

Study of Thermal Decomposition of the Copolymer Based on Polyethylene Glycol Fumarate with Acrylic Acid

Thermal decomposition of the copolymer based on polyethylene glycol fumarate with acrylic acid (p-EGF:AA) at four different heating rates in a nitrogen atmosphere has been investigated by the dynamic thermogravimetry (TGA) method. The TGA curves show that the decomposition process occurs in several stages. The experimental data processed by the Kissinger–Akahira–Sunose and Friedman isoconversion methods made it possible to calculate the activation energy of the main decomposition stage. According to the calculations results, one can see that the values found by these methods do not strongly depend on the conversion. The Achar–Brindley–Sharp method has been applied to determine the compensation parameters. Then, using the compensation effect, the invariant kinetic parameters of the decomposition processes have been found. An experimental curve has been plotted to find the reaction model in comparison with theoretical ones.

Integral Ways of Calculating the Destruction of Copolymers of Polyethylene Glycol Fumarate with Acrylic Acid

Integral Ways of Calculating the Destruction of Copolymers of Polyethylene Glycol Fumarate with Acrylic Acid

Investigation of the destruction of copolymers of poly(ethylene glycol)fumarate with methacrylic acid using differential equations

In the article the thermal characteristics of a copolymer of poly(ethylene glycol)fumarate with methacrylic acid were studied in a dynamic mode in a nitrogen atmosphere for the first time. A kinetic analysis of the thermal destruction process was carried out using three different data processing methods (Freeman-Carroll, Sharp-Wentworth, Achar). Thermodynamic characteristics were also calculated, namely the change in the Gibbs energy (∆G), enthalpy (∆H) and entropy of activation (∆S). The curves of thermogravimetric and differential thermogravimetric analysis of the copolymer were studied in a nitrogen atmosphere at a heating rate of 10 °C/min. The main stage of the copolymer decomposition was found to occur in a narrow temperature range, which is confirmed by a peak in the differential curve. Changes in the reaction rate of the copolymer were shown due to the decrease in the sample mass. It was shown that the results of kinetic analysis depend on the molecular structure of the compounds under study. The activation energies found by the Freeman-Carroll method have lower values, while the Achar and Sharp-Wentworth methods give the same results.

The use of differential calculation methods for the destruction of copolymers of polyethylene glycol fumarate with the acrylic acid

In this work, the thermal decomposition of copolymers based on polyethylene glycol fumarate with the acrylic acid using various ratios of initial monomers has been studied for the first time. The samples were studied in air and nitrogen. According to the thermograms analysis, it was found that the copolymer sample decomposition begins at higher temperatures for a copolymer with high content of polyester resin. The copolymer is vigorously oxidized by the oxygen when heated in air, and one can observe almost complete sample decomposition, whereas it decomposes with a residue of ~ 15% in an inert medium. The activation energies for copolymers with different compositions were estimated using the differential methods of Freeman-Carroll, Achar and Sharpe-Wentworth. The activation energy values found by the three methods demonstrated a good convergence. It was shown that, the activation energy values are higher (~ 200 kJ/mol in the inert medium, and ~ 95 kJ/mol in the oxygen atmosphere) for a copolymer with a lower composition of polyester resin, and the activation energy is ~180 and ~85 kJ/mol for a copolymer with a greater composition of p-EGF-AA. The copolymer is more thermostable in the nitrogen atmosphere according to the kinetic parameters. Additionally, there were determined the thermodynamic characteristics, such as the Gibbs energy (∆G) and the entropy (∆S). They also confirm the destruction process dependence on the components ratio in the synthesized copolymer.

Comparative Analysis of the Thermal Decomposition Kinetics of Polyethylene Glycol Fumarate–Acrylic Acid Copolymers

The thermal decomposition of copolymers based on polyethylene glycol fumarate with acrylic acid in oxygen and nitrogen were studied. The activation energies at different degrees of conversion were evaluated by the Friedman and Flynn–Ozawa–Wall kinetic methods. It was found, using the nonparameteric kinetic methods, that the reaction rate depends on the temperature and degree of conversion in air and inert media.

Combinatorial tissue engineering partially restores function after spinal cord injury.

Hydrogel scaffolds provide a beneficial microenvironment in transected rat spinal cord. A combinatorial biomaterials-based strategy provided a microenvironment that facilitated regeneration while reducing foreign body reaction to the three-dimensional spinal cord construct. We used poly lactic-co-glycolic acid microspheres to provide sustained release of rapamycin from Schwann cell (SC)-loaded, positively charged oligo-polyethylene glycol fumarate scaffolds. The biological activity and dose-release characteristics of rapamycin from microspheres alone and from microspheres embedded in the scaffold were determined in vitro. Three dose formulations of rapamycin were compared with controls in 53 rats. We observed a dose-dependent reduction in the fibrotic reaction to the scaffold and improved functional recovery over 6weeks. Recovery was replicated in a second cohort of 28 animals that included retransection injury. Immunohistochemical and stereological analysis demonstrated that blood vessel number, surface area, vessel diameter, basement membrane collagen, and microvessel phenotype within the regenerated tissue was dependent on the presence of SCs and rapamycin. TRITC-dextran injection demonstrated enhanced perfusion into scaffold channels. Rapamycin also increased the number of descending regenerated axons, as assessed by Fast Blue retrograde axonal tracing. These results demonstrate that normalization of the neovasculature was associated with enhanced axonal regeneration and improved function after spinal cord transection.

New Polyampholyte Polymers Based on Polypropylene Glycol Fumarate with Acrylic Acid and Dimethylaminoethyl Methacrylate

The possibility of preparing new polyampholyte polymers based on polypropylene glycol fumarate–acrylic acid–dimethylaminoethyl methacrylate terpolymers was demonstrated. The main relationships of radical terpolymerization in dioxane, including binary systems participating in the terpolymerization, were studied. The block lengths, transition probabilities, and Harwood block structure parameter were calculated for the terpolymers from the copolymerization constants for the binary systems. These parameters reflect the arrangement of the macroradicals in the chain. The morphology of the polymer surface was studied by scanning electron microscopy, and the surface pore size was estimated. The influence of organic solvents and pH on the sample swelling was studied, and the isoelectric point (pH 6.00) of the terpolymer was determined.

Chitosan/polyethylene glycol fumarate blend films for wound dressing application: in vitro biocompatibility and biodegradability assays

Blending is one of the effective approaches in preparing tailored materials with a wide range of properties. Thus, chitosan-based polymers have been fabricated and used as wound dressings since they possess better properties than those of the constituent materials. The objective of this work was to evaluate the biocompatibility and biodegradability of biodegradable blend films based on polyethylene glycol-co-fumarate (PEGF) and chitosan (Ch). The blend films of Ch/PEGF were prepared by solution casting/solvent evaporation method. Degradation behavior of these blend films was evaluated in a simulated fluid at physiological pH supplemented with lysozyme at a concentration similar to that in human serum by weight loss of the films and changes in the pH of media. When the pH of incubation media was analyzed, with an increase of PEGF content in the blend films, the degradation rate increased accordingly. The pH of the media of samples was not significantly changed at any measured time point and all films kept their integrities during 28 days. The biocompatibility of the films and cell behavior on the surface of these films were investigated by in vitro tests. Biological assessment using mouse fibroblast cell line L929 on the blend films of Ch/PEGF indicated that films supported the attachment, spreading and proliferation of cells. Since the Ch/PEGF films are biocompatible with the tailored biodegradation rate, they might have a great prospective position in the application of wound dressings.

Preparation and characterization of in situ chitosan/polyethylene glycol fumarate/thymol hydrogel as an effective wound dressing

In the present study, polyethylene glycol fumarate (PEGF) was synthesized as a component of blend solutions via polycondensation polymerization and characterized by different tests in order to determine its functional groups and its physical properties included melting and crystallization temperature, enthalpy of fusion and average molecular weights. Wound dressing films based on chitosan (Ch), PEGF and thymol (Th) were fabricated by solvent casting method with different formulations contained 80%(w/w) chitosan and 20%(w/w) PEGF as polymeric components and different amounts of thymol consisted of 0, 0.6, 1.2 and 1.8%(v/v) as pharmaceutical additives of blend solutions. These films were evaluated by different essential tests included Fourier transform infrared spectroscopy (FTIR), tensile testing, water vapor transmission rate (WVTR), water vapor uptake, equilibrium water uptake, water solubility, swelling, scanning electron microscopy (SEM) and antibacterial activity tests. The blend film contained 1.8%(v/v) thymol demonstrated optimal properties included acceptable mechanical properties, better absorption of water vapor or liquid water, higher water vapor transmission rate and air permeability, acceptable water solubility, superior swelling level, more porous structures and rough surfaces and the excellent antibacterial activity against both gram-negative and gram-positive bacteria which make it a suitable candidate for wound dressing applications.

Conductive Graphene Oxide Hydrogel Composites with Functionalized Surface for Nerve Regeneration

Electrically conductive hydrogels composed of graphene oxide and oligo(polyethylene glycol fumarate) (OPF) have been developed for nerve regeneration applications. Graphene oxide was obtained throu...