There have been a number of review papers on layered silicate and carbon nanotube reinforced polymer nanocomposites, in which the fillers have high aspect ratios. Particulate–polymer nanocomposites containing fillers with small aspect ratios are also an important class of polymer composites. However, they have been apparently overlooked. Thus, in this paper, detailed discussions on the effects of particle size, particle/matrix interface adhesion and particle loading on the stiffness, strength and toughness of such particulate–polymer composites are reviewed. To develop high performance particulate composites, it is necessary to have some basic understanding of the stiffening, strengthening and toughening mechanisms of these composites. A critical evaluation of published experimental results in comparison with theoretical models is given.

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Effects of particle size, particle/matrix interface adhesion and particle loading on mechanical properties of particulate–polymer composites

Toughness mechanism in semi-crystalline polymer blends: II. High-density polyethylene toughened with calcium carbonate filler particles

Property improvements of in situ epoxy nanocomposites with reduced interparticle distance at high nanosilica content

Effect of core–shell rubber (CSR) nano-particles on mechanical properties and fracture toughness of an epoxy polymer

Experimental Study of Cement-Asphalt Emulsion Composite

The damage mechanism in tensile testing of glass bead-filled high-density polyethylene was studied byin situ scanning electron microscopy observation, acoustic emission monitoring and volume dilatation tests. The critical damage stress was measured by micromechanical tests. When the stress field of a multiparticle model has been calculated via Eshelby's method, the interfacial bonding strength can be determined.

Microdamage and interfacial adhesion in glass bead-filled high-density polyethylene

The J-integral method was introduced to investigate the fracture process of PP/CaCO3 composites. The results showed that the resistance of PP/CaCO3 composites to crack initiation and propagation was greatly improved with the addition of CaCO3 filler. Large scale plasticity was caused in PP/CaCO3 composites, from which a large amount of energy was absorbed by the PP matrix. The reason for the increase in the fracture toughness of PP/CaCO3 composites was attributed to the partial micro-drawing ahead of the crack tip in the PP matrix, which was formed by the stress concentration caused by the filler particles in the PP matrix and/or by the interfacial debonding between filler particles and the PP matrix. It was indicated that the presence of CaCO3 filler could augment the ductility of composites locally, resulting in higher fracture energy in the crack initiation and propagation of the PP/CaCO3 composites in a certain CaCO3 content range.

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The J-integral fracture toughness of PP/CaCO3 composites

230 Introduction 230 Percolation Model 230 Scaling Law 232 Critical Stress Volume Fraction 234 Experimental 236 Conclusion 237 Acknowledgements 237 References 237 *To whom all correspondence should be addressed 229 Vol 12, No. 3,1993 Percolation Model of Brittle-Ductile Transition in PP/EPDM Blends Abstract A percolation model of brittle-ductile transition in PP/EPDM blends is proposed in the present paper. It is found that the brittle-ductile transition of PP/EPDM blends is compatible with a scaling law in percolation theory. The value of a critical exponent g is 0.42, close to that of the critical geometrical exponent (0.44) in a scaling law. The value of g should be related to the toughness of the blends and be considered as a new parameter. The percolation threshold (Φ^) is related to the ratio of of the rubber particle diameter to the stress volume (d/S), particle-size polydispersity, particle-shape symmetry and interaction between matrix and rubber particles. The brittle-ductile transition behavior of PP/EPDM blends is explained by a percolation model, and the effect of variables on the brittle-ductile transition of PP/EPDM blends is also discussed. Introduction Wu reported a brittle-ductile transition master curve relating the notched Izod impact strength of Nylon-6/EPDM blends with rubber fractions /I/. This transition was interpreted by strong interaction between the polar Nylon-6 matrix and the modified EPDM dispersed phase. However, a similar brittle-ductile transition master curve in non-polar PP/EPDM blends was also observed in this laboratory 1,2,31 (Figure 1). A critical matrix ligament thickness (T ) is a single parameter determining the brittle-ductile transition of the matrix. The value of Τ is independent of rubber volume fraction and particle size and is a characteristic property of the matrix at a given mode, rate and temperature of deformation. The brittle-ductile transition is mainly due to partial yielding of the matrix ligament and its propagation in the matrix /l/, which can be explained by a percolation model. In this paper, we deal with the brittle-ductile transition behavior using a percolation model and also by considering the effect of various parameters on the brittle-ductile transition of PP/EPDM blends.

QI Zong-Neng

Papers

Microdamage and interfacial adhesion in glass bead-filled high-density polyethylene

The J-integral fracture toughness of PP/CaCO3 composites

Percolation model of brittle-ductile transition in PP-EPDM blends

The Correlation Between Particle-Size Dispersity and Percolation Threshold of Brittle-Ductile Transition in Polymer Blends

A New Criterion for Brittle-Ductile Transition of Polymer Blends