Self reinforced polymer composite systems mean that both the reinforcement and the matrix are of the same material but processed through different methods. Their shear and tensile strengths are comparable unlike the glass or carbon fiber reinforced polymer systems where the shear strength is only a fraction of the tensile strength. The system to be investigated are the polypropylene and polyethylene composites. Thermal and mechanical characterization of these systems were carried out which leads to interesting applications in transport, air, sea and land cargo containers, ultra light structures, packaging and electronic packaging.