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.
1 January 2013 in Russian Journal of Applied Chemistry
Effect of the pH of the medium, temperature, and nature of solvents and inorganic salt on the behavior of hydrogels based on copolymers of poly(ethylene glycol) maleate with acrylic and methacrylic...
1 November 2018 in Russian Journal of Applied Chemistry
Comparative analysis of the physicochemical properties of styrene solutions of poly(propylene glycol maleate phthalate) with different initial reactant ratio was performed. Increased content of...
For the first time, the kinetics of isothermal curing and thermal degradation of polyethylene glycol maleate (pEGM)–based systems and their composites with mineral fillers were investigated in the presence of a benzoyl peroxide/N,N-Dimethylaniline redox-initiating system. DSC analysis revealed that the curing process at 20 °C can be described by the modified Kamal autocatalytic model; the critical degree of conversion (αc) decreases with increasing content of the unsaturated polyester pEGM and in the presence of fillers. In particular, for unfilled systems, αc was 0.77 for pEGM45 and 0.60 for pEGM60. TGA results demonstrated that higher pEGM content and the incorporation of fillers lead to increased thermal stability and residual mass, along with a reduction in the maximum decomposition rate (dTGₘₐₓ). Calculations using the Kissinger–Akahira–Sunose and Friedman methods also confirmed an increase in the activation energy of thermal degradation (Ea): EKAS was 419 kJ/mol for pEGM45 and 470 kJ/mol for pEGM60, with the highest values observed for pEGM60 systems with fillers (496 kJ/mol for SiO2 and 514 kJ/mol for CaCO3). Rheological studies employing three-interval thixotropy tests revealed the onset of thixotropic behavior upon filler addition and an increase in structure recovery after deformation of up to 56%. These findings underscore the potential of pEGM-based systems for low-temperature curing and for the design of composite materials with improved thermal resistance.
1 February 2015 in Russian Journal of Applied Chemistry
The radical copolymerization of poly(ethylene glycol maleate) with acrylamide was performed for the first time to obtain 3D cross-linked polymers. The influence of temperature, pH of the medium, and...
The paper presents information on the study of physical and chemical properties of solutions of polyethylene glycol maleate in acrylic acid and products of their ‘cold’ curing. The weight-average molecular weight of the initial polyethylene glycol maleate was established using the GPC method. The value of the degree of unsaturation of both the initial unsaturated polyester and copolymers based on it was determined using the bromide-bromate method. The dynamic viscosity of the polymer-monomer mixture of polyester and acrylic acid was established using viscometry. The density of the stock solutions was analyzed using the pycnometric method and the density of the cured products was determined using the hydrostatic method. The total volume shrinkage of the copolymers was calculated from the obtained density values. The composition of the copolymers was analyzed/studied with the help of HPLC. The degree of swelling of the cured products was also calculated by gravimetric method, and their identification was carried out using IR- and 1Н NMR-spectroscopy. The surface topography of cured copolymers was investigated by SEM. The results obtained indicate to the possibility of controlling the properties of cured unsaturated polyester by varying the initial composition of polymer-monomer mixture depending on its purpose and obtaining on its basis the polymer matrix for the manufacture of bulk products with good physical and chemical properties.