Novel biomass lignin/silica composites were prepared and isolated from rice husk renewable resources at different pHs. Selective precipitation was achieved by decreasing the solution pH from 9.5 to 1.5. When pH reached 3.5, the ratio of lignin and silica mostly achieved the maximum of 1:1. We selected lignin/silica composites as reactants to replace 20 wt% bisphenol A in preparing epoxy resin. The cured novel biomass function lignin/silica-based epoxy resin adhesive showed the highest adhesive strength up to 2.68 MPa, which displayed 123% of neat epoxy resin adhesive. In addition, lignin/silica composites were depolymerized through the hydrothermal method by NaOH as a catalyst, which was used as reactants to replace 35 wt% bisphenol A in the process of in situ synthesis of epoxy resin adhesive. At this point, the high epoxy value (1.42 wt%) and large adhesive strength (3.98 MPa) of lignin/silica-based epoxy resin adhesive were obtained, which adhesive strength was 183% of neat epoxy resin adhesive. The results demonstrated that depolymerized lignin/silica-based epoxy resin adhesive showed the higher epoxy value and the adhesive strength compared with neat epoxy resin adhesive and lignin/silica-based epoxy resin adhesive. Their function in epoxy matrix resulted in better processability.

For the first time, phenolic formaldehyde resin (PF)-treated silica carbon black (SiCB) were prepared with different treatment conditions and their effect as fillers on the mechanical properties of filler filled natural rubber/butadiene rubber (NR/BR) composites were investigated in detail. The PF coating layer on the SiCB derived from rusk husk not only promoted the dispersion of the fillers but also improved the interfacial interactions between fillers and the rubber matrix. As a result, both the cross-link density and mechanical properties of the obtained composites were effectively enhanced. The filler SiCB with 3 wt % PF surface treatment greatly improved the tensile strength of NR/BR composites and reached 7.1 MPa, which increased by 73.7% compared with that of SiCB-filled NR/BR composites. The improved interfacial interactions promoted higher energy dissipation, leading to simultaneously enhancing the glass transition temperature of the obtained composites. Due to the easy processing and low cost of filler as well as the effectively enhanced mechanical properties of composites, the PF-coating methodology has a great potential for practical applications in SiCB reinforced high-performance composites. A commercial filler, carbon black (N774), was also used in this study and evaluated under the same conditions for comparison.

Two factors, the crosslinking degree of the matrix (ν) and the size of the filler (Sz), have significant impact on the Mullins effect of filled elastomers. Herein, the result. of the two factors on Mullins effect is systematically investigated by adjusting the crosslinking degree of the matrix via adding maleic anhydride into a rubber matrix and controlling the particle size of the filler via ball milling. The dissipation ratios (the ratio of energy dissipation to input strain energy) of different filled natural rubber/butadiene rubber (NR/BR) elastomer composites are evaluated as a function of the maximum strain in cyclic loading (ε_m). The dissipation ratios show a linear relationship with the increase of ε_m within the test range, and they depend on the composite composition (ν and Sz). With the increase of ν, the dissipation ratios decrease with similar slope, and this is compared with the dissipation ratios increase which more steeply with the increase in Sz. This is further confirmed through a simulation that composites with larger particle size show a higher strain energy density when the strain level increases from 25% to 35%. The characteristic dependence of the dissipation ratios on ν and Sz is expected to reflect the Mullins effect with mathematical expression to improve engineering performance or prevent failure of rubber products.