Main content area

Structure and Properties of Polymer–Polymer Composites Based on Biopolymers and Ultra-High Molecular Weight Polyethylene Obtained via Ethylene In Situ Polymerization

Khar’kova, E. M., Mendeleev, D. I., Guseva, M. A., Gerasin, V. A.
Journal of polymers and the environment 2019 v.27 no.1 pp. 165-175
Fourier transform infrared spectroscopy, X-ray diffraction, biofouling, catalysts, catalytic activity, cellulose, crystal structure, crystallites, enthalpy, ethylene, irradiation, melting, melting point, modulus of elasticity, molecular weight, oxidation, poly-3-hydroxybutyrate, polyethylene, polymerization, starch, temperature, tensile strength, thermogravimetry, ultraviolet radiation
Polymer–polymer composites (PPC) of biopolymers (starch, cellulose, poly-3-hydroxybutyrate) and ultra-high molecular weight polyethylene (UHMWPE) were obtained by ethylene in situ polymerization (polymerization filling). Ethylene polymerization was carried out in “mild” conditions (25 °C, 0.1 MPa) on a traditional Ziegler–Natta catalyst [TiCl₄ + (C₂H₅)₂AlCl], biopolymer-supported. Catalyst activity increases in the presence of polysaccharides depending on their type and quantity. UHMWPE matrix possesses a molecular weight of 1.20–1.65 MDa, melting point of 138–143 °C, high melting enthalpy and a crystallinity of 60–70%. PPCs generally exhibit better tensile properties than neat polyethylene, such as elastic modulus and elongation at break. Thermogravimetric analysis shows a significant decrease in decomposition temperature and the rate of mass loss on both stages of PPC destruction. The photo-oxidative destruction of PPC after UV-irradiation for different periods of time was studied by FTIR and XRD. Carbonyl indices indicate the rate of oxidation to be 3–4 times greater than in neat PE. Prolonged irradiation leads to a considerable increase in crystallinity and crystallite size. Irradiated PPC films show a 90% extent of biofouling by mold fungi, compared to no growth apparent for neat samples.