Developing high-performance thermosets with outstanding anti-flammability from sustainable resources has attracted increasing attention due to both safety and environmental concerns. Herein, a novel bio-based bis-benzoxazine thermosetting resin has been successfully synthesized via Mannich condensation reaction from paraformaldehyde and natural renewable resources, aesculetin and furfurylamine. Detailed information of the chemical structure for this bio-benzoxazine is analyzed by nuclear magnetic resonance (NMR) and Fourier transform infrared (FT-IR) spectroscopies, elemental analysis and high-resolution mass spectrometry (HR-MS). In addition, the resin polymerization behavior is investigated by differential scanning calorimetry (DSC) and in situ FT-IR analyses. Notably, the fully polymerized bio-thermoset shows high thermal stability with T d10 of 407 °C and T g of 261 °C, and extremely low flammability with heat release capacity (HRC) value of 2.51 J·g −1 ·K −1 and total heat release (THR) value of 0.78 kJ·g −1 . Overall, the current work provides a facile and sustainable synthetic route access to a series of halogen- and phosphorus-free nonflammable bio-thermosets based on smart benzoxazine chemistry.
It is known that magnesium phosphate cements (MPCs) show appreciable mechanical strength and biocompatibility, but the hydration reaction processes often lead to intense heat release while the hydration products present weak resistance to mechanical decay and low bioactivity. Herein we developed an MPC-based system, which was low-heat-releasing and fast-curing in this study, by compounding with self-curing calcium silicate cements (CSCs). The MPC composed of magnesium oxide (MgO), potassium dihydrogen phosphate (KH2PO4), disodium hydrogen phosphate (Na2HPO4), magnesium hydrogen phosphate trihydrate (MgHPO4·3H2O) and chitosan were weakly basic, which would be more stable in vivo. The physicochemical properties indicated that the addition of CSCs could increase the final setting time while decrease the heat release. Meanwhile, the CSCs could endow MPC substrate with apatite re-mineralization reactivity, especially, which add 25 wt.% CSCs showed the most significant apatite deposition. What’s more, the mechanical evolution in buffer demonstrated CSCs could enhance and sustain the mechanical strength during degradation, and the internal constructs of cement implants could still be reconstructed by μCT analysis in rabbit femoral bone defect model in vivo. Particularly, appropriate CSCs adjusted the biodegradation and promoted new bone tissue regeneration in vivo. Totally, the MPC/CSCs composite system endows bioactivity and sustain mechanical strength of the MPC, which may be promising for expending the clinical applications of MPC-based bone cements.
危险品化学品经营许可证（带存储）