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Comparison of thermal, thermomechanical, and rheological properties of blends of divinylbenzene‐based hyperbranched and linear functionalized polymers
Author(s) -
Kabir Sumaya F.,
Adlington Kevin,
Parsons Andrew J.,
Ahmed Ifty,
Irvine Derek J.
Publication year - 2020
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.48547
Subject(s) - materials science , polymer , differential scanning calorimetry , divinylbenzene , polystyrene , glass transition , polymer chemistry , rheology , branching (polymer chemistry) , curing (chemistry) , composite material , copolymer , thermodynamics , styrene , physics
A range of polymer blends were prepared via a solvent‐based film casting process using highly/hyperbranched (HB) polydivinylbenzenes (PDVB) polymers of two different molecular weights, linear functionalized (LF), hydrogenated hyperbranched (H‐HB2) PDVB, and linear polystyrene (LP). The thermal, thermomechanical, and rheological properties of the pure polymers and blends were then investigated and the results related to the concentration of “branched” polymer in the blend and the level of branching/polymer end groups present in the “branched” polymers used. Differential scanning calorimetry (DSC) analysis revealed an increase of the glass transition temperature ( T g ) for the blends containing the nonhydrogenated HBs (~108 °C compared to ~102 °C for LP), which was attributed to crosslinking via the unsaturated reactive chain end/pendant groups in the HB (CHCH 2 ). In contrast at the blends, containing the hydrogenated polymers H‐HB2, exhibited the same T g as LP (~102°C) due to absence of crosslinking from the (H‐HB2) polymer. As the unsaturated HBs were found to be thermally curable, curing temperature rheology measurements were carried out employing a temperature ramp. No specific T gel (the temperature at which HB gets crosslinked) was identified for LP‐HB1 and LP‐HB2 blends, which might be suggested to be due to the fact that both chain entanglement from linear polystyrene. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137 , 48547.