MCA-MMT的制备及其对玻璃纤维增强聚丙烯复合材料阻燃性能的影响

Preparation of MCA-MMT and its effects on flame retardant properties of glass fiber reinforced polypropylene composites

为了提高玻璃纤维(GF)增强聚丙烯(PP)复合材料(GF/PP)的阻燃性能,通过在蒙脱土(MMT)悬浮液中进行三聚氰胺氰尿酸盐(MCA)分子自组装制备了新型协效成炭剂MCA-MMT,并采用FTIR、XRD、SEM和TGA对MCA-MMT的结构及热性能进行了表征;将MCA-MMT、无卤膨胀型阻燃剂与GF/PP熔融共混制备了阻燃复合材料MCA-MMT/(GF/PP),通过极限氧指数(LOI)测试、垂直燃烧试验和锥形量热测试研究了MCAMMT对GF/PP的阻燃效果和阻燃机制,并测试了复合材料的力学性能。结果表明:MMT的加入会影响氰尿酸和三聚氰胺在MCA合成过程中的氢键作用,干扰和抑制大平面氢键网络的形成,减少MCA氢键复合体的分子体积,使颗粒变小。MCA-MMT/(GF/PP)的UL-94防火等级达到V-0级,LOI为31.3%。MCA-MMT的阻燃效率高于传统MCA的,可降低材料燃烧的热释放程度和总烟释放量,使复合材料的阻燃性能提高,其阻燃机制为片层结构的MMT可提高MCA的成炭量,使MCA-MMT/(GF/PP)燃烧后能形成致密的残留炭层。MCA-MMT/(GF/PP)的拉伸、冲击强度与MCA/(GF/PP)的相比并未下降。

In order to improve the flame retardant of glass fiber(GF)reinforced polypropylene(PP)composites(GF/PP),by means of melamine cyanurate(MCA)molecular self-assembly in montmorillonite(MMT)suspension,a new synergistic charring agent MCA-MMT was prepared.FTIR,XRD,SEM and TGA were utilized to characterize the structure and thermal properties of MCA-MMT.Flame retardant composites MCA-MMT/(GF/PP)were prepared by melt blending of MCA-MMT,halogen-free intumescent flame retardant and GF/PP.The flame retardant efficiency and flame retardant mechanism of MCA-MMT toward GF/PP were investigated by limiting oxygen index(LOI)test,vertical burning test and cone calorimeter test.The mechanical properties of composites were also tested.The results indicate that the addition of MMT affects the hydrogen-bond interaction between cyanuric acid and melamine in the synthetic process of MCA,interrupts and inhibits the formation of large planar hydrogen bonding network,and reduces the molecular volume of MCA hydrogen bonding composite which makes the particles smaller.The UL-94 fire rating of MCA-MMT/(GF/PP)reaches V-0,the LOI is 31.3%.The flame retardant efficiency of MCA-MMT is higher than that of traditional MCA,it can reduce the heat release degree and total smoke released,and improves the flame retardant propertier of composites.The mechanism is the MMT with sheet-like structure can improve the char residue amount of MCA,makes the MCA-MMT/(GF/PP)after combustion forms the compact and dense char residue.The tensile and impact strength of MCA-MMT/(GF/PP)do not decrease comparing with those of MCA/(GF/PP).