壳聚糖包覆三聚磷酸钠微胶囊-可膨胀石墨协同阻燃天然/杜仲并用胶

Chitosan coated sodium triphosphate microcapsules-expandable graphite synergistic flame retardant natural rubber/eucommia ulmoides gum

以三聚磷酸钠(STPP)为芯材,壳聚糖(CS)为壁材,通过离子凝胶法成功制备了微胶囊CS@STPP。采用SEM、FTIR及TG对所制备的微胶囊形貌、化学结构和热性能进行了表征。将CS@STPP与可膨胀石墨(EG)以一定比例添加到天然/杜仲(NR/EUG)并用胶中,探究CS@STPP与EG之间的协同作用对NR/EUG阻燃性能的影响。采用极限氧指数(LOI)、垂直燃烧测试(UL-94)、锥形量热仪、拉曼光谱、SEM和电子万能试验机对NR/EUG并用胶的阻燃性能进行了分析。结果表明,当m(CS@STPP)∶m(EG)=4∶1时,制备的NR/EUG并用胶(记为FRBR-5)阻燃效果最优,这归因于CS@STPP与EG的协同作用使形成的炭层结构更稳定致密、连续性更好。此外,FRBR-5的燃烧性能显著降低,其LOI达到28.4%,UL-94达到V-0等级,最大热释放速率为471.7 kW/m^(2)。

Sodium tripolyphosphate(STPP) and chitosan(CS) were used as core material and wall material to prepare microcapsules CS@STPP by ionic gel method. The surface morphology, chemical structure and thermal property of microcapsules were characterized by SEM, FTIR and TG. The effect of synergistic effect between CS@STPP and expandable graphite(EG) on flame retardant performance of natural rubber/eucommia ulmoides gum(NR/EUG) was investigated by adding CS@STPP and EG to NR/EUG in a certain proportion. The flame retardancy of NR/EUG was analyzed by limiting oxygen index(LOI),vertical combustion test(UL-94), cone calorimeter, Raman spectroscopy, SEM and electronic universal testing machine. The results showed that the prepared NR/EUG with m(CS@STPP)∶m(EG) = 4∶1(denoted as FRBR-5) had the best flame retardant effect, which was attributed to the synergistic effect of CS@STPP and EG to the formation of more stable and compact carbon layer structure and better continuity.In addition, the combustion performance of FRBR-5 was significantly reduced, with LOI of 28.4% and UL-94 reaching V-0 rating, and the maximum heat release rate was 471.7 kW/m^(2).