Enhancement and mechanism of NFC doping for improved thermal–mechanical properties of insulating paper.

To enhance the thermal–mechanical properties of insulating paper, nano-fibrillated cellulose (NFC) was used to dope cellulose. The mechanical strength and thermal stability of cellulose insulating paper with different NFC doping mass fractions were analyzed by molecular dynamics simulations and experiments, and the optimal doping ratio of NFC was determined. The results showed that the mechanical properties, thermal conductivity, thermogravimetric properties, and glass transition temperature of NFC-modified insulating paper were improved compared with ordinary insulating paper. Among them, the maximum tensile strength after doping was 58.147 MPa, which was 20.040 MPa higher than the 30.107 MPa of the insulating paper before modification. The glass transition temperature was also 8.54 °C higher than the 127.05 °C before modification. Meanwhile, the mechanism of NFC doping enhancement on the insulating paper's thermal–mechanical properties was analyzed from the aspects of cohesive energy density, fractional free volume, hydrogen bond, and mean square displacement. We believed that the doping of NFC can improve the thermal–mechanical properties of the insulating paper because it could enhance cellulose's interchain force, fill the insulating paper's internal pores, and increase the hydrogen bonding energy. The thermal–mechanical properties of cellulose insulating paper with different NFC doping mass fractions were analyzed to determine the optimal doping ratio of NFC through molecular dynamics simulations and experiments. Meanwhile, the mechanism of NFC doping enhancement on the insulating paper's thermal–mechanical properties was also investigated from the aspects of cohesive energy density, free volume fraction, hydrogen bonding, and mean square displacement. [ABSTRACT FROM AUTHOR]