Dialysis-Free and in Situ Doping Synthesis of Polypyrrole@Cellulose Nanowhiskers Nanohybrid for Preparation of Conductive Nanocomposites with Enhanced Properties

The separation of cellulose nanowhiskers (CNs) from hydrolysis acid and the harmless disposal of the residual hydrolysis acid are two main obstacles that hinder the large-scale production of CNs and CNs based nanocomposites. In this work, the hydrolysis products of CNs without further separation were used as the starting materials for preparation of a CNs supported polypyrrole (PPy@CNs) nanohybrid. During this one-pot synthesis process, the residual hydrolysis acid acted as a doping agent for the synthesized PPy, endowing PPy@CNs nanohybrid with electrical conductivity. Interestingly, the PPy@CNs nanohybrid could be easily isolated from the polymerization products due to the decreased surface charge. Meanwhile, the PPy@CNs nanohybrid showed good suspension stability in alkaline natural rubber (NR) latex, which facilitated the construction of continuous PPy@CNs conductive network in the NR matrix. This PPy@CNs filled NR nanocomposite showed significant improvement in electrical conductivity and mechanical properties when compared with neat PPy/NR composites, and exhibited similar performance to that of PPy@CNs-0 (CNs was isolated by dialysis and virgin doping agent was used) filled NR nanocomposites. The straightforwardness and sustainability of this dialysis-free and in situ doping synthesis of the PPy@CNs nanohybrid should significantly facilitate the scalable fabrication and application of CNs based conductive nanocomposites with high performance.