卡拉胶包覆APP/MnO2增强水性环氧树脂阻燃抑烟性能

Application of carrageenan coated APP and MnO2 to enhance the flame retardant and smoke suppression performance of waterborne epoxy resin

摘要:

用反相乳液法，以卡拉胶（KC）为壳材，聚磷酸铵（APP）和二氧化锰（MnO2）为芯材，制备了KC包覆APP/MnO2阻燃剂（KC-FR）。通过FTIR、 XRD、 SEM和 EDS对KC-FR进行了表征。结果表明：卡拉胶已成功包覆APP和MnO2，合成的样品具有微胶囊结构。将KC-FR应用于水性环氧树脂（EP）中，考察KC、APP、MnO2 三者质量比对EP阻燃、抑烟性能的影响。用极限氧指数（LOI）、垂直燃烧（UL-94）和锥形量热（CCT）测试了涂层的阻燃、抑烟性能。结果发现，当KC/APP/MnO2的质量比为2∶1∶1，并且在EP中添加量为20%时，制备的阻燃涂层EP2的LOI达到29.1%，UL-94达到V-0级，表现出较好的阻燃性能。EP2相比于其它涂层热释放峰值（pHRR）、热释放总量（THR）和烟释放总量（TSP）最低，相比于EP0分别下降了42%、37%和46%，表现出较好的抑烟性能。另外，热重分析（TGA）测试结果显示EP2在800℃残炭量（W800）为33%，表明KC-FR具有促进EP成炭的功能。通过SEM对残炭表面分析发现，EP2表面炭层更加致密，这表明KC-FR对促进形成稳定并且致密的炭层起到至关重要的作用。

Abstract:

The carrageenan-based flame retardant(KC-FR) was prepared by reverse emulsion polymerization, using carrageenan (KC) as shell material, ammonium polyphosphate (APP) and manganese dioxide (MnO2) as core material. KC-FR was characterized by FTIR, XRD, SEM and EDS. It was proved that carrageenan successfully coated APP and MnO2, and it has microsphere structure. The effects of different KC, APP and MnO2 ratios on the flame retardant and smoke suppression properties of waterborne epoxy resin were investigated. The flame retardancy and smoke suppression of the coating were characterized by limit oxygen index (LOI), vertical combustion (UL-94) and cone calorimetry (CCT). The results showed that the limiting oxygen index (LOI) of EP increased from 19.7% to 29.1%, when the ratio of KC, APP and MnO2 were 2:1:1(flame retardant coating EP2), and UL-94 level reached V-0 level, which indicated good flame retardancy properties. At the same time, comparing with EP0, the peak heat release (pHRR), total heat release (THR) and the total smoke production (TSP)of EP2 coating decreased by 42%, 37% and 46%, respectively, which indicated good smoke suppression properties. In addition, the carbon residue was 33% using thermogravimetric analysis(TGA), which indicated the content of KC in KC-FR was the key to the amount of carbon residue. Analysis of the carbon layer using SEM and elemental analysis (EDS) indicated that the surface carbon layer was more compact of EP2, which indicated the KC-FR played an important role in formation of stable and dense carbon layer.