Xiaohua Kong1, Jonathan Curtis1, Liyan Zhao2 and John Wolodko2
1Lipid Chemistry Group, Department of Agricultural Food and Nutritional Science, 4-10 Agriculture/ Forestry Centre, University of Alberta, Edmonton, Alberta, Canada, T6G 2P5
2Alberta Innovates - Technology Futures, 250 Karl Clark Road, Edmonton, Alberta, Canada, T6N 1E4
In oil sands mining operations, oil sands ore is mixed with hot water and pumped down a pipeline from the mine site to extraction facility. A major challenge is the multi-billion dollar cost of maintenance and replacement of these pipeline systems due to material degradation and wear. An efficient way to prevent internal and external corrosion in pipelines is to use an effective protective coating system. Amongst the main coating materials, 100% solid polyurethane (PU) coatings offer high adhesive strength along with high resistance to corrosion and chemical attack. The performance of these PU coatings can be improved further by reinforcement by nanomaterials. Cellulose nanocrystal (CNC) has a crystalline structure with a high aspect ratio, resulting in high scratch and abrasion resistance along with low density and low toxicity. In this work, a simple and novel approach of dispersing CNC into polyols has been successfully developed. The polyol-CNC mixture is a uniform colloidal suspension with no visible macroscopic particles. PU-CNC nanocomposites were produced from the well dispersed polyol-CNC suspension and aromatic diisocyanate using a one shot polymerization procedure. The observation of no large aggregates and a homogeneous distribution of the CNCs in the PU matrix in all nanocomposites, implies that good adhesion between the CNCs and the PU matrix. The incorporation of CNCs improves the abrasion resistance of the PU nanocomposites by about 20% at 0.5 wt% loading level. The combination of the reinforcing effect of stiff CNCs, its covalent bonding to PU matrix as well as its well distribution among the matrix resulted in an optimal enhancement of thermal mechanical and mechanical characteristics of the nanocomposites. The superior mechanical properties of CNC enhanced PU nanocomposites with such low CNC loading level demonstrate that well distributed PU-CNC nanocomposites are successfully achieved, which might be suitable for pipeline coating applications.