不同囊材聚磷酸铵微胶囊在环氧树脂中的阻燃研究

Study on the Flame Retardancy of Microencapsulated Ammonium Polyphosphate with Different Shell in Epoxy Resin

采用原位聚合法合成制备了以蜜胺树脂(MF)、环氧树脂(EP)以及EP和MF为囊材的微胶囊阻燃剂MFAPP、EPAPP、EMFAPP,用红外光谱(FT-IR)和扫描电镜(SEM)表征微胶囊阻燃剂的核壳结构。采用极限氧指数(LOI)和垂直燃烧等级测试(UL94)对MFAPP、EPAPP、EMFAPP在环氧树脂中的阻燃特性进行了研究。当添加量大于7%时,阻燃复合材料均能通过UL 94 V-0级测试,极限氧指数大于27.0%,表明MFAPP、EPAPP、EMFAPP均为EP的高效阻燃剂,这些阻燃剂在EP阻燃过程中均形成了膨胀炭层,属于膨胀阻燃机理。另外在耐水性实验中发现,添加EPAPP、EMFAPP的EP复合材料具有更好的耐水性,经75℃水浸泡6天后,阻燃性能得到了较好的保持。

Three different microencapsulated flame retardants（MFAPP、EPAPP、EMFAPP） are prepared by in situ polymerization.Although with the same core of ammonium polyphosphate （APP）,MFAPP has the shell of melamine-formaldehyde resin（MF）,EPAPP has the shell of epoxy resin（EP）,and EMFAPP has a double shell of MF and EP.Structures of flame retardants are characterized by fourier transform infrared spectroscopy（FT-IR） and scanning electron microscope（SEM）.The flame retardancy of MFAPP,EPAPP and EMFAPP in EP is studied by Limiting Oxygen Index（LOI） and UL 94 tests.When the content of microencapsulated ammonium polyphosphate is more than 7%,all composites can pass V-0 in UL 94 test,and their LOI values are higher than 27.0%.It demonstrates that MFAPP,EPAPP and EMFAPP are great efficient flame retardants for EP.A lot of residual char is formed in the process of flame retardance,its mechanism is intumescent flame retardance.In the experiment of water resistance,composites containing EPAPP and EMFAPP show better water resistance than composites containing other flame retardants.They maintain the good flame retardancy after water treatment（75℃,6 d）.