Premixed cellulose nanocrystal reinforcement of polyamide 6 for melt processing

This work presents a method of industrially viable processing of nanocellulose-reinforced polyamide 6 (PA 6). Cellulose nanocrystal (CNC)-reinforced PA 6 is gaining attention as a promising material for use in the automotive industry due to its highly crystalline, low density, and environmentally friendly nature. However, the low-thermal degradation temperature of CNCs presents problems when melt processing at high temperatures, making it difficult to produce the nanocomposite on a large scale. This article presents a methodology of master batching (MB) using planetary ball milling to embed the CNCs in PA 6. The process of MB CNCs with PA 6 to thermally buffer them was compared to direct milling and hand mixing, prior to melt processing with compression molding. The milled composites had final CNC compositions of either 5 or 10 wt%. Through thermal analysis, it was seen that although both milling methods thermally buffered the CNCs, the presence of the low-molecular weight PA 6 in the MB samples resulted in higher thermal stability. In addition to this, the mechanical analysis showed that the MB samples with 5 wt% CNCs had optimum Young's moduli, ultimate tensile strength, and elongation % at break. Overall, the use of milling for MB to coat the CNCs in polymer is a promising alternative to traditional processes and has potential as a method of industrially manufacturing cellulose reinforced polymer composites.