Gel-type resin poly-acrylonitrile (30 mol%)-NN-dimethylacrylamide (66 mol%)-ethylenedimethacrylate (4 mol%) (ADE) is obtained in very high yield with gamma-rays-sustained polyrnerisation in mass. Water-swollen ADE microparticles react readily with [PdCl42-] in water to give a macromolecular complex likely to be (P)-CN-PdCl3-Na+. The material undergoes facile reduction to a Pdo/ADE nanocomposite, in which a surprisingly non-homogeneous distribution of Pd-0 nanoclusters suggests a remarkable inhomogeneity in the distribution of the -CN groups through the polymer framework. This circumstance is attributed to a marked occurrence of a block-type polymerisation of the acrylonitrile leading to spheroidal domains that are particularly rich in -CN functionalities. Pdo/ADE appears to be an active, re-usable, mechanically and chemically stable catalyst in the model hydrogenation reaction of cyclohexene in methanol under moderate conditions, carried out in batch reactors. (c) 2006 Elsevier B.V. All rights reserved.