Browsing by Author "OPAZO, A"

Now showing 1 - 8 of 8
  • Thumbnail Image
    Item
    BLENDS OF POLY(N-VINYL-2-PYRROLIDONE) POLY(DIALKYL ITACONATES) AND POLY(METHACRYLATES)
    (GORDON BREACH SCI PUBL LTD, 1994) OPAZO, A; GARGALLO, L; RADIC, D
    Blends containing poly(N-vinyl-2-pyrrolidone) (PVP) and poly(dialkyl itaconates) (PDI) and poly(methacrylates) (PMA) with different side chain structures were prepared. polymer blends of various compositions were studied by Differential Scanning Calorimetry (DSC) and Thermomechanical Analysis (TMA). The effect of the substitution on the lateral chain is also analyzed. One Tg value, over the whole range of compositions is observed for the majority of the blends reflecting compatibility. Inmiscible polymer blends are also observed which is apparently dependent on the structure of the side chain.
  • No Thumbnail Available
    Item
    BLENDS OF POLY(VINYLPYRROLIDONE)/ POLY(MONOITACONATES) .1. INTERPOLYMER COMPLEX-FORMATION
    (1992) RADIC, D; OPAZO, A; GUERRERO, X; GARGALLO, L
    Blends containing poly(vinylpyrrolidone) (PVP) of three different molecular weights and poly(monoitaconates) (PMI) with different side chain structures were prepared. Polymer blends of various compositions were analyzed by Differential Scanning Calorimetry (D.S.C.). The calorimetric study was performed on films prepared from methanol and dimethylformamide (DMF). One Tg value is observed for the majority of the samples over a wide range of composition, but in all cases a minimum in the Tg-composition diagram is observed which is attributed to an interpolymer complex formation. The analysis of these systems in solution by using turbidimetry and viscometry techniques for PMMI/PVP confirms the results obtained in the solid state.
  • No Thumbnail Available
    Item
  • No Thumbnail Available
    Item
    FUNCTIONALIZED POLYMERS .1. POLY(DICHLOROALKYL ITACONATES) - SYNTHESIS AND SOLUTION PROPERTIES
    (1992) RADIC, D; DANIN, C; OPAZO, A; GARGALLO, L
    The synthesis of poly(di-2-chloroethyl itaconate) (PD2CEI) and poly(di-3-chloropropyl itaconate) (PD3CPI) was carried out. The dilute solution behaviour of these polymers in tetrahydrofuran and chloroform at 298 K has been studied, by viscometry, membrane osmometry, and size-exclusion chromatography (SEC) measurements. The Kuhn-Mark-Houwink-Sakurada relationships were established. The flexibility factors sigma and C(infinity) and the thermodynamic parameters B were calculated using the Stockmayer-Fixman equation. The results obtained are compared with those found for the corresponding poly(methacrylates) and the poly(dialkyl itaconates), and discussed in terms of specific influence of the chlorine incorporated in the side chain.
  • No Thumbnail Available
    Item
    MISCIBILITY OF POLY(2,6-DIMETHYL-1,4-PHENYLENE OXIDE) POLY(VINYL PYRROLIDONE) BLENDS
    (1991) OPAZO, A; GARGALLO, L; RADIC, D
    The miscibility of blends of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and poly(vinylpyrrolidone) (PVP) was studied by differential scanning calorimetry (DSC) through the analysis of the glass transition temperature Tg. The dependence of Tg with the annealing temperature was determined for PPO and PVP samples of different molecular weights. The phase diagrams for blends containing three different PVP samples were established. Blends of PPO and PVP were found to be miscible for composition lower than 30% and higher than 65% of PVP. A inmiscibility window between 30 and 65% of PVP is also described.
  • No Thumbnail Available
    Item
    MONOALKYLITACONATES VINYLPYRROLIDONE COPOLYMERS .2. REACTIVITY RATIOS AND VISCOMETRIC BEHAVIOR IN DILUTE-SOLUTIONS
    (1993) RADIC, D; OPAZO, A; VILDOSOLA, G; GARGALLO, L
    Copolymerization of mono-n-octyl, mono-n-decyl and mono-n-dodecyl itaconate with vinylpyrrolidone (MOI-VP, MDI-VP and MDoI-VP) was carried out using AIBN as initiator. The monomer reactivity ratios were determined by the Fineman-Ross and Kelen-Tudos methods. Values of r1 and r2 were found to be less than unity for MOI-VP, MDI-VP and MDoI-VP, corresponding to random copolymers with some tendency to alternance. Copolymers of various compositions were studied in solution, and Mark-Houwink-Kuhn-Sakurada relationships were established in ethanol for MOI-VP and MDI-VP copolymers, and in 1-propanol for MDoI-VP. The rigidity factors sigma and the characteristic ratio C(infinity) were obtained from K(theta) values determined by using the Stockmayer-Fixman relation. In all the copolymers the introduction of vinylpyrrolidone units produces flexibility of the polymer chain relative to the poly(monoitaconate) homopolymers, and the solution properties of these copolymers can be described by assuming a random coil model instead of a rigid rod or wormlike model as in poly(monoitaconates).
  • Thumbnail Image
    Item
    THERMAL-STABILITY OF POLY(CHLOROALKYL METHACRYLATE)S AND POLY(DICHLOROALKYL ITACONATE)S
    (ELSEVIER SCIENCE BV, 1992) RADIC, D; OPAZO, A; TAGLE, LH; GARGALLO, L
    Thermogravimetric analyses of fractions of poly(2-chloroethyl methacrylate) (P2CEM), poly(3-chloropropyl methacrylate) (P3CPM), poly(di-2-chloroethyl itaconate) (PD2CEI) and poly(di-3-chloropropyl itaconate) (PD3CPI) of similar molecular weight distribution were carried out. The effect of the nature and structure of the side chain on the thermogravimetric behaviour is investigated, together with the thermal behaviour of these two groups of polymers. The relative thermal stability of the polymers studied is PD3CPI > PD2CEI > P3CPM greater-than-or-equal-to P2CEM, by comparison of the temperature of their initial thermal degradation. The results are discussed in terms of the nature and structure of the different side chains. The kinetic parameters for the thermal degradation process were established. All samples show a first-order kinetic model for the degradation process.
  • No Thumbnail Available
    Item
    THERMAL-STABILITY OF POLY(MONO-N-ALKYL-ITACONATES) AND MONO-N-ALKYLITACONATE-CO-VINYLPYRROLIDONE COPOLYMERS .1.
    (1994) RADIC, D; TAGLE, LH; OPAZO, A; GODOY, A; GARGALLO, L
    Poly(monoitaconates) containing octyl, decyl and dodecyl groups and random monoalkylitaconate-co-vinylpyrrolidone copolymers were studied by thermogravimetric analysis. Copolymers of mono-n-octylitaconate (MOI), mono-n-decylitaconate (MDI), and mono-n-dodecylitaconate (MDoI), respectively, with N-vinyl-2-pyrrolidone (VP) of different compositions were studied by dynamic thermogravimetric analysis. The thermal stability of the copolymers depends on the structure of the monoitaconate comonomer and on the composition of the copolymer. The kinetic analysis of the degradation data shows that the thermal decomposition of these copolymers can be described by several kinetic orders depending on the copolymer and on the composition. The relative thermal stability of the copolymers increases as the VP content increases and as the length of the side chain of the itaconate increases, following the same trend as the flexibility of the copolymers in solution.