Reinforcement of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) composites using cellulose nanocrystals: Enhanced electrostatic and filtration properties.

Biomass poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB) shows great potential for filtration membranes but faces challenges in processability, mechanical strength, and electrostatic adsorption. In this study, we addressed these challenges by enhancing the processing, mechanical, and electrical properties of P34HB through the addition of biomass fillers, CNC-PVAc, which were prepared by grafting high-modulus cellulose nanocrystals (CNC) onto polyvinyl acetate (PVAc). The CNC-PVAc/P34HB composites demonstrate enhanced processability and superior properties, including increased strength (2.61 MPa), a higher dielectric constant (3.49), elevated surface potential (2.50 kV), and remarkable triboelectric performance, with an open-circuit voltage of 18.49 V and a short-circuit current of 124.59 nA. These excellent properties make the membrane a promising candidate for novel filters utilizing electrostatic adsorption generated by self-produced static electricity, primarily due to the functional groups in CNC-PVAc. For 10wt CNC-PVAc/P34HB membranes, at 10 L/min airflow rate, the filtration efficiency for PM0.3 and PM2.5 reaches 97.13 % and 99.99 %, respectively, with a pressure drop of only 49 Pa. The effective filtration performance is primarily due to the dual mechanism of physical interception and electrostatic adsorption, which is enhanced by the addition of CNC-PVAc. These membranes are designed for high-efficiency particulate filtration, biodegradable air filters, addressing the need for sustainable, high-performance filtration materials.