Modification of glass fiber reinforced isotactic polypropylene composites by β-nucleating agent

Research on the influence of glass fiber(GF) and β-nucleating agent(TMB-5) on the mechanical properties of glass fiber reinforced polypropylene composites (GFRPP) was carried out. Tensile strength and modulus increased as the content of GF augmented, while tensile strain at break decreased. The addition of TMB-5 improved the impact strength by inducing the formation of β-crystallites. GFRPP samples attained maximum impact strength when mass fraction of β-nucleating agent was 0.05%. The sample with 0.20% β-nucleating agent and 30% GF in mass fraction possessed the best mechanical properties, of which the tensile strength and impact strength reached 39.04 MPa and 7.21 kJ/m², respectively. The results of differential scanning calorimetry showed that GF depressed the activity of β-nucleating agent. Scanning electron microscope observation of the fracture surface of injection-molded GFRPP also illustrated that the samples with β-nucleating agent were in favor of improving the impact strength by changing the crystal form to β-form and thus making the matrix softer.