Effect of component interaction on the melting and crystallization characteristics of pe/pib blends

Linear low density polyethylene/polyisobutylene blends were prepared in the entire composition range. Non-isothermal and isothermal crystallization of the samples was carried out and melting behavior was studied as a function of composition and crystallization temperature. The equilibrium melting temperature of the neat PE and the blends was determined by the Hoffman-Weeks extrapolation technique. Flory-Huggins interaction parameters were calculated by the approach of Nishi and Wang. The decrease of melting temperature with increasing PIB content indicated the interaction of the polymers in the melt. Both irregular chain structure of the crystalline polymer and interaction lead to a decrease of the equilibrium melting temperature and maximum lamellar thickness. The results prove that even relatively weak dispersive forces can lead to the miscibility of two polymers.