Effects of Matrix Properties on Brittle-Ductile Transition of HDPE/SEBS Blends—Verification of Leibler Toughening Model
In order to investigate the effects of matrix properties of high density polyethylene(HDPE)on the brittle-ductile transition of the blends,styrene-ethylene/butylene-styrene(SEBS)/HDPE blends were prepared by melt blending.The particle sizes and distributions of the dispersed phases were observed by scanning electron microscopy,which clarified the quantitative relationships between the matrix properties and the critical interparticle distance(IDc).The results show that as the fusion index of matrix HDPE decreases,the critical elastomer mass fraction required for the brittle-ductile transition of the blend is smaller,and the particle size of dispersed phase SEBS is smaller,which is more favourable to the brittle-tough transition of the blend.Meanwhile,the brittle-ductile transition of blends has a strong relationship with the fracture strength(σB)and the yield strength(σY)of the matrix material.A larger(σB/σY)2 leads to a greater IDc,and the brittle-ductile transition of blends is more likely to occur.This finding confirms the validity of Leibler's toughening model.Additionally,the average distance between two adjacent microcracks(ξ∗)and the coefficient(C)are determined through the linear fitting.
High Density PolyethyleneStyrene-Ethylene/Butylene-Styrene Block CopolymerBrittle-Ductile TransitionCritical Interparticle Distance
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