Highly porous composites of poly(glycidyl methacrylate-co-1,3-butanediol dimethacrylate) and pullulan were prepared as semi-interpenetrating polymer networks by cross-linking of high internal phase emulsions (HIPEs). HIPEs were prepared by using an aqueous phase made of pullulan dissolved in deionised water. Instead of conventional cross-linkers such as divinyl benzene, 1,3-butanediol dimethacrylate was used as a flexible co-monomer. Morphological and mechanical properties of the porous composites with an initial pullulan loading ranging from 1 to 10 wt % have been investigated. Resulting composites were tested in terms of uniaxial compression stress and it was found out that the use of pullulan and flexible co-monomer in the HIPE preparation increases the compression modulus from 13.53 to 30.8 MPa. Textural analyses of the resulting composites show that in all cases open cellular foams composed of primary cavities (approximate to 112-74m) connected with secondary interconnected pores were produced with a specific surface area in the range of 1.7-3.0m(2) g(-1). In addition, the influence of using porogen in the oil phase was investigated. It was found that using a porogen reduces the cavity size diameter from approximate to 112 to 20 mu m and increases the compression modulus from 13.53 to 47.06 MPa. POLYM. ENG. SCI., 55:2636-2642, 2015. (c) 2015 Society of Plastics Engineers