Toughening of vinylester-urethane hybrid resins through functionalized polymers

O. Gryshchuk, N. Jost, J. Karger-Kocsis

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

Liquid nitrile rubber, hyperbranched polyester, and core/shell rubber particles of various functionality, namely, vinyl, carboxyl, and epoxy, were added up to 20 wt % to a bisphenol-A-based vinylester-urethane hybrid (VEUH) resin to improve its toughness. The toughness was characterized by the fracture toughness (Kc) and energy (Gc) determined on compact tensile (CT) specimens at ambient temperature. Toughness improvement in VEUH was mostly achieved when the modifiers reacted with the secondary hydroxyl groups of the bismethacryloxy vinyl ester resin and with the isocyanate of the polyisocyanate compound, instead of participating in the free-radical crosslinking via styrene copolymerization. Thus, incorporation of carboxyl-terminated liquid nitrile rubber (CTBN) yielded the highest toughness upgrade with at least a 20 wt % modifier content. It was, however, accompanied by a reduction in both the stiffness and glass transition temperature (Tg) of the VEUH resin. Albeit functionalized (epoxy and vinyl, respectively) hyperbranched polymers were less efficient toughness modifiers than was CTBN, they showed no adverse effect on stiffness and Tg. Use of core/shell modifiers did not result in toughness improvement. The above changes in the toughness response were traced to the morphology assessed by dynamic mechanical thermal analysis (DMTA) and fractographic inspection of the fracture surface of broken CT specimens.

Original languageEnglish
Pages (from-to)672-680
Number of pages9
JournalJournal of Applied Polymer Science
Volume84
Issue number3
DOIs
Publication statusPublished - Apr 18 2002

    Fingerprint

Keywords

  • CTBN
  • Core/shell rubber
  • Crosslinking
  • Fracture mechanics
  • Hyperbranched polyester
  • Modification
  • Thermosets
  • Toughening mechanisms
  • Vinylester-urethane hybrid resin

ASJC Scopus subject areas

  • Chemistry(all)
  • Surfaces, Coatings and Films
  • Polymers and Plastics
  • Materials Chemistry

Cite this