Kinetic stabilisation of cellulose nanocrystals
Cellulose nanocrystals (CNC) at low loading levels were shown to reinforce a photocurable coating resulting in improved adhesion. A polyether polyol containing CNC at loading levels of up to 1.8 wt% was grafted with 3-isopropenyl-α,α-dimethylbenzyl isocyanate to functionalise it with a photocurable group. The nanoparticles were kinetically stabilised in the rapidly forming prepolymer of high viscosity. Photoinitiators and a difunctional reactive diluent were added to produce optically transparent coatings and free films upon irradiation by ultraviolet (UV) light.
CNC nanoparticles improve adhesive strength
This allowed evaluation of the effects of CNC at low loading levels in a glassy polymer matrix obtained through a rapid cure system. Incorporation of CNC nanoparticles in the polymer matrix resulted in an average improvement in adhesive strength of 154% while enhancing tensile strength by an average of 16%. The technique described could be used as a new approach to reduce adhesive failure in UV-curable coatings without sacrificing their mechanical strength.
The study is published in: Progress in Organic Coatings Volume 129, April 2019, Pages 101-115.