The present work reports the preparation of a porous structure by electron beam irradiation of interpenetrating polymer network (IPN) based on polyethylene and poly(methyl methacrylate-co-butyl methacrylates). Thin IPN films were synthesized by in situ polymerization. Low-density polyethylene (PE) was used as the first IPN component, and the second IPN component was formed by copolymerization of methyl methacrylate and butyl methacrylate. After the synthesis the methacrylic phase is finely dispersed in a PE matrix. Porous films of these materials were obtained by decomposition of the polymethacrylate phase by means of electron radiation followed by extraction with xylene.
The thermal stability in N 2 atmosphere of the irradiated and extracted IPN was improved compared with the unirradiated samples. Three temperature regions of weight loss were observed, two of them caused by the copolymer and one by the PE.
The lowering of the melting temperature of PE observed by differential scanning calorimetry analysis indicated an increase in crosslinking caused by irradiation. Morphology changes were studied by scanning electron microscopy which revealed a porous surface structure of the irradiated and extracted samples. Flux measurements showed that some irradiated samples were permeable to ethanol, demonstrating an interconnected porous structure which may be relevant for membranes.