Browsing by Author "RIBESGREUS, A"

Now showing 1 - 4 of 4
  • No Thumbnail Available
    Item
    CALORIMETRIC STUDY OF SOME POLY(MONO-NORMAL-ALKYL ITACONATES)
    (1991) DIAZCALLEJA, R; RIBESGREUS, A; GARGALLO, L; RADIC, D
    A calorimetric study of poly(mono-n-alkyl itaconates) containing 8, 10, 12 and 14 carbon atoms in the side chain was performed. No glass transition temperature (T(g)) was observed in the temperature range 213-263 K, but a melting process was observed for the dodecyl and tetradecyl derivatives, which was attributed to crystalline order in the long side chains.
  • No Thumbnail Available
    Item
    DIELECTRIC-RELAXATION BEHAVIOR OF POLY(CYCLOHEXYLMETHYL METHACRYLATE) AND POLY(BENZYL METHACRYLATE)
    (1989) RIBESGREUS, A; DIAZCALLEJA, R; GARGALLO, L; RADIC, D
  • No Thumbnail Available
    Item
    DIELECTRIC-RELAXATION BEHAVIOR OF POLY(MONO-N-ALKYL ITACONATES)
    (1991) RIBESGREUS, A; DIAZCALLEJA, R; GARGALLO, L; RADIC, D
    Dielectric relaxation measurements on a family of poly(mono-n-alkyl itaconates) have been performed. Two relaxation peaks have been observed within the temperature range studied. The first one at lower temperature (153 K at 1 kHz), which we call the gamma-peak and have attributed to motion in the lateral chains involving methylene sequences, depends on the length of the side-chain. The second relaxation labelled-beta (233 K at 1 kHz) is related mainly to motion of the lateral group. A peculiar behaviour has been observed in the case of poly(mono-tetradecyl itaconate). The results have been discussed in terms of the different possible motions of the side-chains.
  • No Thumbnail Available
    Item
    DIELECTRIC-RELAXATION IN POLY(MONOBENZYL ITACONATE)
    (1991) DIAZCALLEJA, R; RIBESGREUS, A; GARGALLO, L; RADIC, D
    The dielectric relaxation properties of poly(monobenzyl itaconate) have been studied and four relaxation processes (alpha, beta, gamma and delta) have been found. These processes respectively appear in the decreasing order of temperatures 100, 20, -42 and - 110-degrees-C at 2 kHz. The best defined relaxations, alpha and gamma have been described in terms of semiempirical models. Different molecular origins for each relaxation have been proposed by comparison with other polymers of similar structures, particularly with poly(benzyl methacrylate). In the general case, the higher complexity of the side chains in poly(methacrylates) as well as in poly(itaconates) involves the possibility of multiple relaxation mechanisms that are not always easy to interpret.