Simple and Rapid Adhesion of Commodity Polymer Substrates under Ambient Conditions Using Complexed Alkylboranes

Abstract

Adhesives are ubiquitous in manufacturing spanning nearly all sectors from healthcare and photovoltaics to aerospace and electronics. Yet many commercial polymers remain challenging to adhere, necessitating either pretreatment, mechanical fastening, or adhesive processes that involve specialized equipment, high temperature/vacuum, and long cure times. Thus, rapid-cure adhesives for polymers that can set under ambient conditions using simple procedures are desirous because they offer cost savings, faster production, and greater design freedom to producers. Herein, we report a powerful adhesive platform that bonds a wide scope of commodity polymers via (hydrogen) atom transfer and free-radical (graft) polymerization initiated with a trialkylborane–ligand complex and isocyanate decomplexing agent. The developed adhesive formulation is air-stable, bulk, and operates in air at room temperature using a high-glass-transition temperature polyacrylate, i.e., poly(isobornyl acrylate). The alkylborane-initiated bonding process is rapid (∼30 min), requires minimal surface preparation (cleaning and mild roughening), and successfully bonds seven diverse substrates including polytetrafluoroethylene, polyethylene, polypropylene, polycarbonate, nylon, polymethylmethacrylate, and polyvinylchloride. This contribution uniquely investigates the process–property relationships for the adhesive formulation, lap-shear performance, mechanism of failure, and a reactive additive for enhancing the adhesive’s glass-transition temperature to ∼120 °C (polyhedral oligomeric silsesquioxane or POSS) to widen its operation temperature. We envision that the reported alkylborane-initiated adhesion platform could hold promise in the automotive, aerospace, and marine sectors as means for rapid manufacturing and structural adhesion.

Three-Arms PLA/PS Copolymer Based on 2,5-Dihydroxy-1,4-Benzoquinone

“…Recently A.J.D. Magenau et al proposed adhesives based on tributylborane 3-methoxypropylamine complex [13]. An alkylborane initiated RAFT-polymerization (AI-RAFT) method was developed independently in the groups of X. Pan [14][15][16][17] and A.J.D.…”

Alkylborane initiated RAFT polymerization: impact of carboxylic acid deblockers

“…3,4 In other areas, alkylboranes have been employed as a rapid, strong, and ambient condition adhesive system for low surface-energy polymeric substrates through hydrogen atom transfer and concurrent graft-and radical-polymerization with methacrylate (co)polymers 5,6 or acrylate polymers. 7 Radical generation with alkylboranes has also been utilized, historically and recently, as an initiator for free radical polymerization of acrylate, methacrylate, vinyl ether, and fluorinated monomers, amongst others. [8][9][10][11] Alkylborane chemistries in combination with reversible addition-fragmentation chain-transfer (RAFT), a topic more germane to this work, were recently discovered in a number of reports.…”