Functional group tolerance of AOTEMPO-mediated peroxide cure chemistry. (2nd September 2016)

• Record Type: Journal Article
• Authors: Molloy, Brian M.; Johnson, Kelli-anne; Ross, Rachel J.; Parent, J. Scott
• Is Part Of: Polymer. Volume 99(2016)
• Page Start: 598
• Page End: 604
• Publication Date: 2016-09-02
• Subjects: Cross-linking -- Polymer modification -- Nitroxyl trapping; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2016.07.067
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: Delayed onset formulations for the peroxide-initiated crosslinking of a range of commodity polymers are described. 4-Acryloyloxy-2, 2, 6, 6, -tetramethylpiperidin- N -oxyl (AOTEMPO) is effective for controlling the crosslinking dynamics and yields of linear low density polyethylene (LLDPE), poly(ethylene- co -vinyl acetate) (EVA), poly(ethylene- co -propylene) (EPR), and poly(ethylene- co -propylene- co -ethylidenenorbornadiene) (EPDM). However, the cure additive is inefficient for butadiene-based materials such as 1, 2-polybutadiene (vinyl-BR) and cis -1, 4-poly(butadiene) ( cis -BR), since macroradical trapping by AOTEMPO stunts diene-monomer oligomerization, thereby eliminating multiple crosslinks that cannot be restored by a single polymer-bound acrylate group. Additional crosslink yield losses arise from allylic alkoxyamine instability, the details of which are revealed by independent 1 H NMR and rheology studies. Graphical abstract: Highlights: AOTEMPO-mediation of peroxide cures is examined for a range of polymers. Delayed onset is achieved with cure yield recovery for saturated polymers. Unsaturated polymers suffer from kinetic chain length issues and alkoxyamine instability.