Destruction of the resins structure due to heating
This article considers a polymer composition based on acetone-formaldehyde (AFR) resin, which is used to reduce water influx into the well bore during the repair insulation work. Pumping into the well bore a composition, based on AFR resin, results in self-heating that causes destruction of its own structure and, therefore, the damage of the polymer blend structure. The purpose of the present article is to find the causes of AFR resin self-heating when injected into the well bore as part of the composite mixture that leads to the destruction of its structure. Author considers exothermic reaction between AFR resin and aqueous solution of sodium hydroxide during the curing of the polymer composition. The features of the given polymer structure are studied as well. The need for further studies of the resin structure is substantiated. Based on the study conducted, five possible reasons of the AFR resin self-heating, leading to destruction of resin structure, are revealed. Recommended practices that may decrease self-heating of the AFR resin are offered.
Relaxation phenomenon in composite materials
Dielectric measurement characteristics such as the dissipation factor, relative permittivity and conductivity as a function of temperature and frequency have been achieved on composite materials based on different epoxy resins filled with alumina inclusions. The analysis of the results show the presence of porosity and inhomogeneity in these materials. The study of the dissipation factor, as a function of temperature at high frequencies, has shown an unexpected absorption phenomenon in materials designed to be utilized as electrical insulators. The identification of the entities responsible for this relaxation shows that the entities result from one of the components of the material. These results can also confirm the inhomogeneity of the materials.
Synthesis, Characterization and Glass-Reinforced Composites of Acetone–Formaldehyde–Phenol Resins
Acetone–formaldehyde (AF) resin having the methylol group (–CH2OH) has been prepared and characterized. The condensation of AF resin with phenol (P) was carried out in the presence of alcoholic alkali catalyst at varying ratios of AF:P, namely 1:1, 1:1.5 and 1:2. The resultant AFP resins were characterized by elemental analysis, IR spectral studies, number average molecular weight (M n) estimated by non-aqueous conductometric titration, and thermogravimetry. The curing study of AFP resins with hexamethylene tetramine (HMTA) was monitored by differential scanning calorimetry (DSC) and kinetic parameters were evaluated. Glass-reinforced composites based on the AFP–HMTA system have also been prepared and characterized.