The incorporation of nanocellulose-doped insulating paper into the material composition of a given structure has been demonstrated to enhance the material’s mechanical properties and retard the development of cracks. However

the effects of different length-to-diameter ratios of nanocellulose are different. In this paper

multi-scale doped modified insulating paper with different mass fractions were prepared. The modification mechanism of multi-scale doped modified insulating paper and its advantages were analysed in terms of the dynamic reorganisation of hydrogen bonding during the fracture process of the insulating paper

fibre bridging during the development of microcracks

and the interfacial and agglomeration effects of microfibrillated/nanocellulose

modified paper retains insulating properties while enhancing mechanical properties. At the same time

based on the Halpin–Tsai model

introducing the fibre orientation factor and incorporating the calculation of agglomerate and interfacial phases was also undertaken. This approach enabled the prediction of Young’s modulus for multi-scale doping system and single-scale doped modified insulating paper

and the optimal ratio of multi-scale mixed fibre doping is derived based on the modified mechanical model. The experimental findings demonstrate that the modified mechanical model exhibits numerical stability and universality in terms of Young’s modulus prediction error

with a maximum error of 6.07% and a minimum error of 0.7% across different batches of insulating paper. The multi-scale doped modified insulating paper and the mechanical quantitative model hold significant potential in enhancing the mechanical properties of insulating paper and its prediction.