Study On The Application Of Modified Magnesium Hydroxide And Compound Flame Retardant In Polymers

Magnesium hydroxide(MH)is one of the rapidly developing environmentally friendly inorganic flame retardant additives.It has the triple functions of flame retardant,filling,and smoke suppression.However,its compatibility with high molecular polymers is very poor.It is not easy to disperse and cause agglomeration phenomenon,and lacks affinity with the polymer matrix.Therefore,ultrafine treatment or surface modification of the magnesium hydroxide particles is required.This thesis adopted three surface treatment technologies: solution modification method,blend coating method,and graft modification.The modifier could improve its surface compatibility with polymers under different processes with chemically coated,physically coated,and grafted on the particle surface.The influence of the preparation process of modified magnesium hydroxide on the structure and surface properties of the modified body and the application rules in natural rubber,styrene-butadiene rubber and ethylene-propylene rubber were systematically studied.First,the effects of modifier and dosage on the modification effect were studied separately.Under certain conditions,the preliminary surface modification of magnesium hydroxide was completed by a coupling agent to obtain a modifier-coated magnesium hydroxide modified body.Then,graft modification was carried out on the basis of preliminary modification to obtain magnesium hydroxide graft modification through solution polymerization.The results showed that the surface properties of magnesium hydroxide were significantly improved after modification,and the surface hydrophilicity of modified styrene(St)and methyl methacrylate(MMA)was significantly weakened,and the activation index was also increased accordingly.The prepared magnesium hydroxide modified body was applied to natural rubber.The research results showed that the natural rubber filled with modified magnesium hydroxide significantly improved the processing,vulcanization,dynamic and static mechanical properties and dispersion.The synergistic effect of magnesium hydroxide and various halogen-free complex systems was studied.The coordination of each component improved the overall performance of NR through reaction or promotion.Compared with pure magnesium hydroxide,the processing fluidity and mechanical properties of the NR coordination systems were improved,and the modification and compounding improved the compatibility with the NR matrix.The flame retardant efficiency of single magnesium hydroxide was low,and due to the synergistic effect of the compound system,the flame retardant performance was excellent,and the surface of the residual carbon was more compact and compact,and the flame retardant performance of the phosphorus-containing compound system was better.The modified magnesium hydroxide coated by blending was applied to SBR and EPDM.The research results showed that the modified magnesium hydroxide in SBR and EPDM improved the vulcanization process and processing performance to different degrees,and greatly improved the dynamic and static mechanical properties.At the same time,the residual carbon content of the rubber compound was increased,the combustion speed was slowed down,and the flame retardant performance was improved,and the modified particles had a better surface wetting effect in the rubber matrix,and the microscopic dispersibility of the silane-modified magnesium hydroxide was the most excellent.