Engineering cellulose nanofibril aerogel for reinforcing polymethyl methacrylate with superior mechanical strength, high transparency, and improved thermal stability

Abstract

In this study, a new strategy for preparing cellulose nanofibers/polymethyl methacrylate (CNF/PMMA) composite with high strength and high transmittance was developed. The UV curing technique was adopted to induce the polymerization of MMA and the grafting modification of methacryloylated CNF aerogel (CNF_MA). The compatibility between CNF aerogel and PMMA was significantly improved through the grafting modification of CNF aerogel. The cold ultraviolet photopolymerization strategy makes the polymerization reaction much milder. The transmittance of the CNF_MA/PMMA composite was 86.45 %, showing only a slight reduction compared to PMMA. Its tensile strength increased to 69.21 MPa, about twice that of PMMA, and 1.5 times that of CNF_pure/PMMA, proving the interaction between CNF and PMMA was greatly enhanced due to the successful grafting of PMMA onto the surface of CNF. The glass transition temperature is 108.1 °C, which increased by nearly 20 %. The thermal stability has also been improved, as reflected by a 10 % increase in the initial pyrolysis temperature. Overall, this work provides a mild and green preparation method for CNF/PMMA composites, making them suitable for applications in the field of high-strength organic glass.