Synthesis of Daidzein and Thiophene Containing Benzoxazine Resin and Its Thermoset and Carbon Material

The Preparation of an Environmentally Friendly Novel Daidzein-Modified Lignin Phenolic Resin with High Performance and Its Application in Friction Materials

The preparation of biological phenolic resin (PF) with green recyclable biomaterials instead of phenol is a research hotspot for solving current resource and environmental problems. In this study, on the basis of introducing lignin into the phenolic system, daidzein of a renewable resource with a rigid structure was selected to modify lignin-based phenolic resin (LPF), and the improvement of the mechanical and thermal properties of the modified phenolic resin under different substitution ratios was studied. The friction materials were prepared with a daidzein-modified lignin-based phenolic resin (D-LPF) as the matrix binder, and their effects on the mechanics and friction and wear properties of friction materials were investigated. The results show that when the proportion of daidzein replacing phenol is 12%, the highest Tp can reach 152.4 °C, and the Tg of the modified D-LPF resins is significantly higher than those of PF and LPF. The highest Ts of D-LPF is 203.3 °C, which is also significantly higher than those of PF and LPF (184.7 °C and 174.6 °C, respectively). The maximum carbon residue rate at 800 °C is 64.2% and is greatly improved compared with the 55.1% and 56.7% of PF and LPF. The bending strength and impact strength of D-LPF-matrix friction materials are obviously higher than those of PF- and LPF-matrix friction materials. The specific wear rate of D-LPF-matrix friction materials is 0.70 × 10-4 mm3/Nm, which is obviously lower than those of PF- and LPF-matrix friction materials and shows good applicational prospect as a matrix resin in friction materials.

Bio-Based Thermosetting Resins: From Molecular Engineering to Intrinsically Multifunctional Customization

Recent years have witnessed a growing interest in bio-based thermosetting resins in terms of environmental concerns and the desire for sustainable industrial practices. Beyond sustainability, utilizing the structural diversity of renewable feedstock to craft bio-based thermosets with customized functionalities is very worthy of expectation. There exist many bio-based compounds with inherently unique chemical structures and functions, some of which are even difficult to synthesize artificially. Over the past decade, great efforts are devoted to discovering/designing functional properties of bio-based thermosets, and notable progress have been made in antibacterial, antifouling, flame retardancy, serving as carbon precursors, and stimuli responsiveness, among others, largely expanding their application potential and future prospects. In this review, recent advances in the field of functional bio-based thermosets are presented, with a particular focus on molecular structures and design strategies for discovering functional properties. Examples are highlighted wherein functionalities are facilitated by the inherent structures of bio-based feedstock. Perspectives on issues regarding further advances in this field are proposed at the end.