TEMPERATURE-DEPENDENCE OF THE STRESS-STRAIN PROPERTIES OF POLYETHYLENE MODIFIED BY GRAFTING ACRYLIC-ACID

Stress-strain diagrams of a copolymer of polyethylene with acrylic aci d were recorded in the 293-363 K temperature range. The dependence of stress-strain properties of the copolymer on concentration of acrylic acid and grafting initiator (dicumene peroxide) was investigated. It i s shown that the dependence of the breaking stress calculated with res pect to the cross section at the moment of failure of the copolymer on temperature is linear in character. The dependence has a bending poin t that divides it into two linear segments, which is due to the existe nce of a relaxation period. On the basis of the kinetic equation of th e useful life of solids, values of the activation energy of mechanical destruction and the structure-sensitive coefficient gamma were calcul ated for each linear segment.