Cure-on-demand wood adhesive on cards

A team of researchers from Louisiana State University demonstrated, for the first time, a cure-on-demand wood adhesive using thermal frontal polymerisation with Southern Pine wood.

Monomer structure, initiator loading, and filler loading all had an impact on the strength of the adhesive and the cure-on-demand ability. More flexible, ethoxylated monomers produced stronger adhesives; though the ethoxylate groups reduce the ability of the system to be polymerised frontally.

The researchers also demonstrated that fillers help overcome decreases in strength. Addition of a highly reactive comonomer (acrylic acid) to increase molecular weight between cross links along with the ethoxylated triacrylate increased the propensity for frontal polymerisation and made a tougher polymer.

Increasing initiator loading could help ensure front propagation, but a maximum initiator loading was reached where the gaseous by products of the peroxide initiator made the network highly porous and thus lacking strength. Fillers such as kaolin and sawdust helped overcome decreases in strength at high initiator loadings.

Source: www.woodnews.in