Orientation Effects in Hybrid-Polymer Mixtures

Composites based on melts of boron-oxide oligomer (BOO) and low-density polyethylene (LDPE) in the polyoxide-concentration range of 0–64 vol % were synthesized. The measurements of the thermomechanical and mechanical properties of the composites showed the incompatibility of the mixture components. The abnormal increase in the strength and the Young’s modulus of the LDPE/boron-oxide oligomer mixtures under the tension of molded composite specimens was registered in the range of 25–50 vol % polyoxide. The anomalies were explained as being due to polyoxide-fiber formation and confirmed by the electron-microscopy images. The abnormal changes in the differential pressure in a melt flow and the torque of an extrusion auger were observed in the same polyoxide-concentration range, which was explained by the polyoxide orientation in a melt flow and its planar structure. The chemical structure of boron-oxide oligomer exposed to extrusion mixing and its distribution within a molded specimen of the mixture were analyzed by IR spectroscopy. The opportunity to synthesize hydrolytically stable composites in a wide range of ratios owing to the polyoxide encapsulation in a polyethylene matrix was shown.