Study On The Preparation And Properties Of Rubber/Lignin-Phenol-Formaldehyde Resin Composites

In this study, the composites material of plastic and rubber were prepared from nitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR) and polybutadiene rubber (BR) and lignin-phenol-formaldehyede (LPF) prepolymer. The morphology and properties of NBR/LPF, SBR/LPF and BR/LPF composites prepared were studied.LPF resin was synthesized with a ratio of lignin to phenol. The gel permeation chromatography (GPC) result showed that with the incorporation of lignin in the resol resin's formula, both the average molecular weight and the polydispersity increased gradually, due to the larger and non-uniform molecular weights of the lignin. The miscibility of LPF with ethanol was investigated. It was found that the miscibility of LPF with ethanol was better than lignin, which shows that the lignin molecular structure of LPF has changed. From the FTIR spectra analysis it was shown that the self-polymerization of LPF resol was synthesized successfully.LPF was applied to NBR, SBR and BR to prepare the NBR/LPF, SBR/LPF and BR/LPF composites, respectively. The mechanical properties, thermal properties, morphology and compatibility of the composites were evaluated. It was found from SEM and DSC analysis that as the LPF content of the composites increased, the microstructure of composite became rougher. As the LPF content was above30%, there is an interpenetrating effect existing in the composites. The compatibility of both networks was not improved, and the SBR/LPF and BR/LPF have pahse separation obviously. The experimental results of mechanical properties showed that the composites incorporated with LPF display a remarkable improvement in mechanical properties, and the content and composition of LPF have an effect on its mechanical properties. Its tensile strength,100%modulus, tear strength, and shore A hardness increased with LPF content increasing, while elongation at break decreased with increase in LPF content. When composites is filled with30%of LPF (lignin30%-phenol70%), NBR/LPF (70/30) has the best comprehensive properties, and tensile strength, tear strength,100%modulus and shore hardness have an increase of186%,164%,227%and33%, respectively. When composites is filled with20%of LPF (lignin30%-phenol70%), SBR/LPF (70/30) has the best comprehensive properties, and tensile strength, elongation at break, tear strength and shore hardness have an increase of262%,110%,61%and16%respectively. When composites is filled with20%of LPF (lignin30%-phenol70%), BR/LPF (70/30) has the best comprehensive properties, and tensile strength, elongation at break, tear strength and shore hardness have an increase of281%,425%,119%and33%, respectively. The experimental results of thermal properties showed that incorporation LPF into rubber material, the T50%(50%weight loss) of composites was increased. The NBR/LPF and SBR/LPF composites display a remarkable improvement in the aging properties, but the aging properties of BR/LPF was not improved.