Starch–polyethylene polymer–polymer composites obtained by polymerization filling: Structure and oxidative degradability

The polymer–polymer composites bearing polyethylene and starch are obtained by polymerization filling. The polymerization of ethylene is carried out using catalyst system TiCl₄ + (С₂H₅)₂AlCl] under mild conditions. It is found that the catalyst activity in the presence of a biopolymer is higher than that without the filler. The polyethylene matrix has a molecular mass of 1.26–1.40 M and features a melting point of 138–140°C, a high enthalpy, and a degree of crystallinity of 60–70%. Reduction in the decomposition temperature of the polymer–polymer composites and in the rate of mass loss compared to the unfilled polyethylene and biopolymers is detected. The stress-strain characteristics of the polymer matrix are improved; in particular, the elastic modulus and relative elongation at break are increased. The photooxidative degradation of the composites under the action of sunlight and UV radiation is studied. According to the data of IR spectroscopy, the polymer–polymer composites possess resistance to photooxidative aging 2–3 times lower than the unfilled polyethylene. The polymer–polymer composites subjected to UV radiation reveal a high intensity of growth of microorganisms: the degree of biofouling is up to four points.