Influence of cobalt stearate on destabilization of high-pressure polyethylene

Introduction. The main purpose of research is to provide a timer-based polymer composition of high pressure polyethylene and cobalt stearate, which starts self-destruction through a certain period of time and can be used in the production of minipackets for packing food products in supermarkets and further reduce environmental pollution. Materials and methods. To determine the technological parameters processing of the compositions were performed thermomechanical and differential thermal analysis of cobalt stearate. To assess the destabilizing impact of cobalt stearate in the mixture held in the timer determination shrinkage conditional strength and elongation, getting dry residue by dissolving in xylene and water absorption. Infrared spectroscopy was used to assess the destabilizing effect on the molecular level. Results and discussion. In determining the properties of cobalt stearate the thermomechanical curve confirmed by the plateau crossing from the pseudo-crystalline to the amorphous state. Analysis was conducted with next parameters: starting temperature measuring 16.8 degrees C, weighed material - 24.1 mg, the sensitivity of apparatus - 20mg, rising of temperature 10 degrees/min, weight loss after full cooling oven 85.5 %, the decomposition start temperature - 200 degrees. The optimal concentration is area of 3% in which the shrinkage of film sample was 46%, the value of the conventional longitudinal strength decreases after 3 months of exposure, corresponding to the climate zone of central Ukraine. After dissolving samples in xylene percentage of lost mass was 99.74%, which is a comparative characteristic for assess the depth of degradation chains. In determining of water absorption, the maximum exposure available for next investigation is 8 hours, at which water absorption is 21.4%. Infrared spectroscopy with increasing irradiation time gives the highest rate of ketone groups formation (in the range 1710-1725 cm(-1)), alcoholic groups (1150 cm(-1)) and a significant increase in the amount of water adsorption (3360 cm(-1)) at a concentration of cobalt stearate within 3%, which also demonstrates depth of chains degradation on molecular level. Conclusion. The timer-based polymer composition based on high-pressure polyethylene and cobalt stearate is designed with maximum efficiency in the area of 3%, proved its effectiveness and efficiency.