Radiation grafting of poly(vinyl acetate) onto wheat straw and properties of the product

Poly(vinyl acetate) (PVAc) was grafted onto wheat straw by c-irradiation to improve the compatibility between wheat straw and high-density polyethelene (PE).The grafting was proved by Fourier transform infrared(FTIR) spectroscopy. The compact structure of wheat straw was loosened because the chemical bonds and crystalline structure were destructed by the c-rays. The modified wheat straw needed less energy for thermal transition, as revealed by differential scanning calorimetry (DSC).Thermal analysis revealed that grafted PVAc acted as a protective barrier for the wheat straw and leads to an increase in maximum pyrolysis temperature. The crystallite size of grafted wheat straw decreased to 5.33 nm from5.63 nm before irradiation. There were holes in melted form appeared on the surface of the grafted wheat straws.Both the grafted PVAc and irradiation are beneficial to lower the torque of wheat straw/PE melts and improve its mechanical properties by 36%. Possible mechanism of irradiation grafting was proposed.