Award-winning paper in 2020

The Green Materials Prize was awarded to Arévalo et al. (2020).

In this work, the feasibility of producing low-cost, recyclable and biodegradable binderless all-cellulose fibreboards was demonstrated through the successful manufacturing of self-binding composites based on recycled paper and kraft fibres. These all-cellulose composites were made by a simple and environmentally friendly solvent-free mechanical fibrillation method using water as a processing aid. Kraft fibres and recycled paper pulp were mixed in a 30/70 w/w ratio and refined simultaneously in a Valley beater for different periods of time. The mechanical properties of the composites, consisting of a ‘matrix’ of recycled paper reinforced with kraft fibres, were highly dependent on the level of fibrillation of the kraft fibres. Optimal levels of fibrillation resulted in a good balance of self-binding properties and reinforcing efficiency. The hot-pressed all-cellulose panels exhibited a flexural strength of 75 MPa and a modulus of 5.9 GPa, which are impressive values compared with those of conventional fibreboard materials. In addition, these panels showed better water resistance than some existing wood panel products. These binder-free all-cellulose composites have potential as cost-effective sustainable alternatives to existing panel board products, as they are entirely made from renewable and recycled materials, which at the end of life can potentially be recycled or composted, making them perfectly fit for a circular economy.