The aim of this work is to elucidate the relationship between lignin main features and its behavior in natural rubber compounds, in particular focusing on thermal stability and mechanical properties. Five lignins obtained from different sources and through different extraction processes were characterized in terms of purity, sulfur content, molecular weight distribution (GPC), qualitative and quantitative functional group distribution (FTIR and 31 P-NMR). Then the lignins were incorporated in natural rubber by two different approaches, namely co-precipitation and dry-mixing. Thermal stability and mechanical properties of lignin/natural rubber blends were investigated in both masterbatches and vulcanized compounds. The Oxidation Induction Time (OIT) was used to determine the thermal stabilization of the lignin-NR masterbatchs, while tensile stress-strain properties of the compounds were evaluated after vulcanization. It was found that differences in the chemical and morphological characteristics of lignin influence its antioxidant and reinforcement capability. The addition of lignin to vulcanized compounds demonstrated the possibility to improve mechanical properties hypothetically through a tandem mechanism of protection and reinforcement.

A series of diorganotin dicarboxylates of the general formula (CH3)2Sn(OCOCHR3CHR2GeR1)2 where R1=(C6H5)3, (P-CH3C6H4)3, N(CH2CH2O)3, R2=C6H5, H, CH3, P-CH3OC6H4, P-ClC6H4, P-CH3C6H4, R3=CH3 and H, have been synthesized by the reaction of dimethyltin oxide with germanium substituted propionic acid in 1:2 molar ratio in toluene. The H2O formed was removed azeotropically using a Dean and Stark apparatus. All the compounds have been characterized by IR, multinuclear (1H, 13C, 119Sn) NMR, mass and Mössbauer spectroscopies. All compounds were found to have potential activity against bacteria.

This work describes the development of a low‐density, renewable, and high reinforcing filler for natural rubber (NR) compounds. The cellulose nanocrystal (CNC)‐based hybrid filler was synthesized by decorating the surface of CNCs with silica using a simple and efficient coprecipitation method. The properties of the prepared hybrid were investigated by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, nitrogen physisorption measurements, and Thermogravimetric analysis. Then, the prepared hybrid was incorporated in NR using two different approaches, namely, dry mixing and coprecipitation. The dynamic and tensile mechanical properties of the hybrid/NR compounds were evaluated indicating that: the coprecipitation method was found much more effective for homogeneous dispersion and the CNC/silica hybrid provided quite higher reinforcement to NR than reference silica; however, much lower density of the final compounds was obtained. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48332.