Preparation and properties of composites consisting of two continuous interpenetrating phases, at least one of them is the polymer phase, are presented. Three different kinds of such composites are discussed: polymer-polymer (PVC-PMMA), polymer-mineral (PMMA-gypsum) and polymer-metal (PVC-Wood alloy). Composites were prepared by filling the porous matrix made of one component with other component in the liquid state which was then solidified by polymerization (PMMA) or cooling (Wood alloy). The obtained composites were characterized mainly by mechanical testing, e.g. elasticity modulus, flexural strength and Brinell hardness. In some cases other measurements, such as microscopic and electrical, were also carried out. It was found that obtained composites possess many interesting properties. The introduction of the second component into the matrix pores as a rule increases the mechanical properties by few times, even if its content is relatively small.

This work presents composite materials with interpenetrating network structure based on thermoplastic polymer and low melting metal alloy. Composites with various alloy content were prepared by PVC powder sintering to obtain polymer matrix with open pores. Then, liquid Wood's metal was intruded into the matrix using a pressure autoclave. Obtained composites have been studied with respect to microstructure, mechanical, thermal, and electrical properties. SEM micrographs revealed good dispersion of metal in the matrix but at low loading levels it is incomplete. Addition of metal improved mechanical properties, especially flexural strength. Electrical resistivity of samples varies from 10 À4 to 10 À5 X m and these values are typical of conductors. The measurements of electromagnetic interference shielding effectiveness (EMI SE) shows that generally PVC/Wood's metal composites have a good ability to shield electromagnetic waves. Composites containing more than 15 vol % Wood's metal exhibited EMI SE above 40 dB in the major part of frequency range.

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