Study On The Flame-retardant And Mechanical Properties Of Magnesium Hydroxide In Linear Low-density Polyethylene

In the study of linear low density polyethylene?LLDPE?halogen free flame retardant system,the environmentally friendly metal-hydroxide flame retardant agents based on Aluminum hydroxide?ATH?and magnesium hydroxide?MH?own great development prospect.However,in order to achieve an index of flame-retardant,such flame retardants often require high filling amount which would result in the deterioration of the processability and mechanical properties.Therefore,it is significant to solve the minimal efficiency problem of flame retardant by modifying MH and compositing with other efficient flame retardant synergistic agent.The modification of MH was obtained via dry process method in the thesis.We had investigated the effects of six different types of silane coupling agent modified MH of LLDPE/MH blends on mechanical properties and flame retardant.And we studied the processing properties,mechanical properties and flame retardant properties of LLDPE/MH in the condition of different size of MH under different content of composites.The synergistic processing properties,mechanical properties and flame retardant properties effect on LLDPE of MH with nano silicon dioxide?Nano-SiO₂?,micro encapsulated red phosphorus?P?and silicone powder?silicone?was investigated.The melt mass flow rate?MFR?was used to characterize the material flow properties.We tested the tensile fracture,lengh at break and impact strength of the flame retardant LLDPE,and observed the micro morphology of the flame retardant materials by transmission electron microscopy?SEM?.Differential scanning calorimetry?DSC?was applied to analysise the effects of the flame retardant particles on crystallization behavior of the matrix resin LLDPE.The combustion performance of flame retardant material was tested by the methods of limiting oxygen index,vertical burning?UL-94?,thermal gravimetric?TGA?and cone calorimeter heat?CONE?.The results showed that the silane coupling agent 11-110 was the best modifier,the mechanical properties of material deteriorated sharply when the content of MH is more than 50%.when the materials comprehensive of nano silica,micro encapsulated red phosphorus and silicone powder addition were 0.5%,2%,6%respectively,the performance is the best.In addition,nano silica,MRP,silicone powder and MH had a good flame retardant synergistic effect.