AbstractThe structure and morphology of poly(tetrafluoroethylene)‐poly(N‐vinylpyrrolidone) (PTFE‐PVP) copolymer membranes prepared by direct radiation grafting were studied by using differential scanning calorimetry, x‐ray diffraction, and scanning electron microscopy. The granulometry of the base emulsion used in PTFE film forming did not have any influence on the mechanism of radiochemical grafting. Moreover, it is proposed that the size of base grains induces morphologies of grafted membranes which differ markedly from each other. The results are analyzed on the assumption that grafted chains of PVP are formed between the base grains of PTFE and gradually move inward toward the crystalline zones. For a given grafting ratio, the space of distribution of grafted chains inside the PTFE matrix depends on the size of PTFE base grains. A correlation between morphologies of membranes and water permeability of copolymer membranes is in
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