THE INFLUENCE OF EXTERNAL FACTORS ON THE POLYETHYLENE, FILLED WITH POLYSACCHARIDES
The influence of external factors on the composite material - polyethylene (PE) high-filled with polysaccharides (PS) was investigated. The objects of study were selected composition "PE: PS" in the ratio of 70 : 30 wt.%, respectively, in the qualities of PS used pure microcellulose, waste microcellulose and starch; as the object of comparison used pure PE. The compositions in the form of a sheet were obtained by compounding using a twin-screw extruder at a temperature of 170 °C. External factors were chosen: dilute acid and alkali solutions, elevated and negative air temperature, as well as natural climatic factors, including solar UV radiation. Strength parameters were estimated according to GOST 11262-80 using a tensile machine RM-50 with the StretchTest software. Tests for resistance to chemical media were carried out in accordance with GOST 12020-72, using 0.1 n solutions of sodium hydroxide, sulfuric acid and acetic acid, for a month, taking samples every 7 days, and determined the mass of samples, thickness, elongation and tensile strength. Frost resistance was evaluated at 5-fold freezing / thawing of samples, resistance to high temperatures was evaluated in the air at a temperature of 60°C. the Influence of natural climatic factors, including solar UV radiation, was evaluated in the warm period of the year for 6 months. It was found that the strength parameters of composite materials do not change under the action of elevated air temperature (60 °C, exposure time-28 days) and natural solar UV radiation (exposure time-6 months), but under the influence of the aqueous medium (pH = 7.0, exposure time-28 days) and solutions of sulfuric and acetic acids 0.1 n (pH = 1.2 and 3.0, respectively, - 28 days) there was a tendency of slight increase in strength for polyethylene filled with starch, and a tendency of slight decrease in strength for polyethylene filled with microcellulose; with 5-fold freezing/defrosting, a decrease in strength parameters for all the samples was recorded. Based on the data obtained, the diffusion coefficients of water, solutions of sulfuric and acetic acids, sodium hydroxide (0.1 n) for polyethylene filled with starch and microcellulose were calculated.