A reactive flame retardant containing biphenyl structure (DEU-2DOPO) was prepared from the bio-based raw material eugenol. The incorporation of DEU-2DOPO into the epoxy resin serves to enhance the ring-opening reaction of the epoxy. Furthermore, the inclusion of DEU-2DOPO has been found to have a positive impact on the glass transition temperature and residual carbon rate of the epoxy resin. This additive also significantly improves the mechanical properties of the epoxy resin, leading to a 49.3% increase in tensile strength, an 81.9% increase in breaking elongation, and a 15.8% increase in flexural strength. Notably, when DEU-2DOPO is introduced at a concentration of 5 wt%, it not only achieves a V-0 rating in the UL-94 test but also exhibits an impressive ultimate oxygen index of 34.5%. Additionally, the cone calorimetric testing revealed that the presence of DEU-2DOPO results in lower combustion metrics compared to pure epoxy, as evidenced by a reduction of 15.1% in total heat release (THR) and 10.8% in total smoke release (TSR). An analysis of the flame retardant mechanism elucidates that DEU-2DOPO promotes the formation of a stable and dense residual carbon, thereby impeding gas and heat exchange. Furthermore, the decomposition of DEU-2DOPO generates PO· and PO2· radicals, which effectively neutralize reactive radicals.
Jing Zhou,Xingang Li,Jinze Du,Lin He,Chengyang Wang,Hong Sui
A new resourcezation way has been proposed to address the treatment challenges of the light phenolic distillation residue (LPDR) from the coal-based phenolic distillation residue. Herein, the LPDR, which was collected at 20 kPa and 220 °C from the phenolic distillation residue, has been further used to synthesize the phenolic resin (named as RPF) for MgO-C refractories. It is found that the conversion efficiency of crude phenol mixture to RPF is 71.3%, which is lower than that of pure phenol. To increase the conversion efficiency and improve the properties of RPF, the crude phenolic mixture was blended with pure phenol for the synthesis. The optimal addition mass ratio of phenol in the crude phenol mixture (phenol/total phenolic compounds) is determined to be 0.8, where the obtained RPF could satisfy or even better than the national standard. Further addition of 10 wt% of urotropine (HMTA) as curing agent and 9 wt% of ferrocene (Fc) as modifier (named as MRPF) are found to significantly improve the graphitization of RPF. Under these conditions, the DTG at temperature of maximum mass lose rate (T max ) of MRPF was lower than that of commercial resin. The graphitization level was as high as 61.6% with the residual carbon rate up to 41.4%, which are higher than those of national standard. These findings provide insights for the resourcezation of the phenolic distillation residue.
A stable and highly efficient 1, 1, 3, 3, 3-hexamethyldisilazane (HMDS) terminated m-Cresol inhibitor was synthesized based on the protection-deprotection strategy. The inhibitory effect of HMDS terminated m-Cresol inhibitor on spontaneous combustion of lignite was explored through temperature-programmed oxidation tests, in-situ infrared analysis and thermogravimetric analysis. Results show that, the oxidation of active phenolic hydroxyl groups in the m-Cresol inhibitor can be hindered by the protection of HMDS. After encountering coal, the HMDS terminated inhibitor can be gradually deprotected to regenerate the m-Cresol inhibitor that contains massive active phenolic hydroxyl groups, thus improving the chemical inhibition efficiency of coal spontaneous combustion. For the coal sample inhibited with HMDS terminated m-Cresol inhibitor, the initial contents of the active functional groups are lower and more stable during heating, and the inhibition rate reaches 70% at 130 °C. Moreover, the crossing-point temperature rises by 32.4 °C–181.2 °C. The activation energy increases by 11 kJ/mol and 18 kJ/mol at below and above 130 °C respectively. The peak temperature at maximum weight loss rate rises by 65 °C–431.2 °C, and the corresponding residual carbon rate increased by 31.3%–61.6%. The inhibition mechanism of the HMDS terminated m-Cresol inhibitor on coal spontaneous combustion was deduced.
危险品化学品经营许可证（带存储）