膨胀阻燃多层膜改性苎麻织物/苯并噁嗪树脂层压板的制备及性能

为提高苎麻织物作为复合材料增强体时的阻燃性能，首先，采用层层组装法在苎麻织物表面构筑了氨基化多壁碳纳米管（MWCNT）-聚磷酸铵（APP）与聚乙烯亚胺（PEI）-APP膨胀阻燃多层膜；然后，将改性后的苎麻织物与苯并噁嗪树脂复合制备了苎麻织物/苯并噁嗪树脂层压板，并研究了层压板的热降解行为、阻燃性能与力学性能。结果表明:与纯苎麻织物/苯并噁嗪树脂层压板相比，含MWCNT-APP与PEI-APP膨胀阻燃多层膜的层压板热释放速率峰值由106.6 W·g-1降低至53.4 W·g-1和53.0 W·g-1，总热释放量由12.3 kJ·g-1降低至7.6 kJ·g-1和9.0 kJ·g-1，极限氧指数由23.5提高至27.2和27.0，UL94级别由无级别提高至V-0和V-1级，弯曲强度由81 MPa提高至122 MPa和143 MPa，弯曲断裂伸长率由1.2%提高至1.4%和1.7%，拉伸性能也得到了一定的改善。所得结论表明使用MWCNT-APP与PEI-APP膨胀阻燃多层膜可在提高层压板阻燃性能的同时，改善其力学性能。 

Preparation and properties of intumescent flame retardant multilayer coatings treated ramie fabric/benzoxazine resin laminates

In order to improve the flame retardant properties of ramie fabrics used as the reinforcing material in composites,amino-functionalized multiwall carbon nanotube (MWCNT)-ammonium polyphosphate (APP)and polyethylenimine (PEI)-APP intumescent flame retardant multilayer coatings were constructed on the surfaces of ramie fabric via layer-by-layer assembly method firstly.Then,the modified ramie fabrics were composed with benzoxazine resin to prepare ramie fabric/benzoxazine resin laminates,and the thermal degradation behaviour,flame retardant properties and mechanical properties of laminates were investigated.The results show that compared to the pristine ramie fabric/benzoxazine resin laminate,the peak values of heat release for the laminates containing MWCNT-APP and PEI-APP intumescent flame retardant multilayer coatings decrease from 106.6 W · g-1 to 53.4 W·g-1 and 53.0 W·g-1 ,the total heat release decrease from 12.3 kJ·g-1 to 7.6 kJ·g-1 and 9.0 kJ· g-1 ,the limiting oxygen indexes increase from 23.5 to 27.2 and 27.0,the UL94 level increase from no rating to V-0 and V-1 levels,the flexural strengths increase from 81 MPa to 122 MPa and 143 MPa,the flexural elongations at break increase from 1.2% to 1.4% and 1.7%,and the tensile properties also show improvements to a certain de-gree.The conclusions obtained show that using MWCNT-APP and PEI-APP intumescent flame retardant multilayer coatings can not only improve the flame retardant properties of laminates,but also improve the mechanical properties at the same time.