Study On Inorganic-organic Composites Flame-retardant Polyoxymethylene

Polyoxymethylene(POM)is a kind of thermoplastic engineering plastic with excellent mechanical properties,its LOI is only 15%,which makes POM very easy to burn and limits its application.Therefore,it is of great significance to improve the flame retardant properties of POM.In order to improve the flame retardant properties and reduce the influence of the mechanical properties of POM,the flame retardant POM was studied from the aspects of flame retardant type,amount of flame retardant,kind of intumescent flame retardant system,type and content of compatibilizer.A variety of analysis and testing methods are used to test and characterize the structure and properties of materials,the main results obtained are as follows:The effects of single flame retardant type,additive amount and different intumescent flame retardant systems on the flame retardancy of POM materials were investigated.The results showed that APP,MEL,PER,ATH,zinc borate and cerium oxide have some effects on the flame retardancy of POM.When the amount of flame retardant added is 30 %,the flame retardancy of POM composites was improved.The effects of different ratios of APP/MEL/PER and ATH/APP-MEL-PER on the performance of POM were studied by orthogonal test,the results show that the flame retardants in the two kinds of compound flame retardant system can form a synergistic flame retardant effect on the flame retardancy of POM,but the effect is not good.The flame retardancy of POM with zinc borate / APP-MEL-PER composite flame retardant system was studied.The boron phosphate formed by the reaction between APP and zinc borate enhanced the stability and compactness of flame retardant POM combustion charcoal.When the mass ratio of APP:zinc borate became larger,it was easier to play a synergistic effect to enhance the carbon layer stability and compactness.When APP: MEL: PER: zinc borate = 8: 4: 3: 1,the LOI of fire-retardant POM was 44% and the Flame Class reached UL-94 V-0.When change the additive amount of zinc borate,the flame retardancy of the material first increases and then decreases with the increase of zinc borate dosage.When the amount of zinc borate is 1%,the flame retardants formed a good synergistic flame retardancy,the material's LOI as high as 55%,the Flame Class is UL-94 V-0.KH-560 was used to modify the materials.The mechanical properties of KH-560 first increased and then decreased with the addition of KH-560.when KH-560 was added at 1%,its tensile strength is 29.86 MPa,the LOI is 54% and Flame Class obtain UL-94 V-0.Effects of the mass ratios of each component of cerium oxide/APP-MEL-PER complex fire-retardancy system on the properties of the materials were studied.The flame retardants exerted a synergistic flame retardant effect.Cerium oxide enhanced the stability of the carbon layer.When the mass ratio of APP: MEL: PER: cerium oxide is 8: 4: 3: 1,the LOI is 47% and the Flame Class is UL-94 V-1.Change the dosage of cerium oxide,the flame retardancy of the material first increases and then decreases with the increase of cerium oxide dosage.When the content of cerium oxide is 0.3%,the synergistic flame retardant effect of the flame retardant in the complex system is optimized,the material's LOI was up to 52% and the Flame Class was UL-94 V-0,but the mechanical properties of the material are greatly reduced.KH-560 was used to modify POM.When the additive amount of KH-560 is 1.0%,the tensile strength of flame retardant composites was 24.75 MPa and the LOI was 54%,the Flame Class reached to UL-94 V-0,compared with the non-modified POM flame retardant materials,the mechanical properties have greatly improved.