The Preparation Of Acrylic Ester Copolymer And Application In Flame Retardant Foaming Polypropylene Wood Plastic Composite Materials

The wood plastic composite materials is a kind of new common composite materials which has great market development potential and composited by wood powder and thermoplastic polypropylene.It's based on the ordinary wood plastic composite material,then add the foaming agent to implement foam.Eventually get the foaming product with excellent appearance,lower density and economic.In the process of preparation add some flame retardant to improve flame retardant performance and fulfill the requirements of flame retardant.In the foam process recipe of PP-WPC,acrylic ester foaming regulator can improved the PP-WPC processing performance and mechanical properties,adjust the foaming effect.This research has divided into three aspects: first is the synthesis process research of acrylic ester foaming regulator,then the preparation of vermiculite modified polypropylene wood plastic flame retardant foam composite material;the last is the applied research of Acrylic ester foaming regulator in vermiculite modified polypropylene wood plastic.In the first stage,Multi-stage emulsion polymerization was used to prepare block copolymer used as foaming regulator,with methyl methacrylate(MMA),butyl acrylate(BA)and styrene(St)as monomers.Though IR,Raman,DSC and GPC characterization methods,with viscosity,conversion rate and gel rate as indexes,the particle size and distribution of emulsion are considered,we can finally determine the optimal preparation processing of foaming regulator: When the ratio of soft monomer and hard monomer is that BA:(St+MMA)=1:3,the optimal proportion of monomers is MMA:St=4:1;The optimal proportion of initiators is: KPS: 0.15%,SHS: 0.05%,AINB: 0.15%;The optimal content of chain extender is: DVB: 0.3%.In the second stage,studied the preparation processing of polypropylene foam wood plastic composite materials.Use alkali liquor pretreatment of wood powder,and add silane coupling agent,through the test prototype,TEM and the torque rheometer to test the performance of the composite materials.Research the influence of wood powder with different content to composite materials about mechanical properties,process ability,and the effects of the foaming.Then use vermiculite to modify the flame retarding performance and thermal stability of composite materials,after a series of tests such as TG and LOI,vermiculite can obviously improve the thermal stability and LOI of PP-WPC,The optimal proportion of additive amount is: wood powder 20wt%,vermiculite 10wt%.In the last stage,added the St-ACR which is prepared in the first stage into the Vermiculite modified polypropylene wood plastic flame retardant foam composite material,investigate the mechanical properties,rheological properties and microstructure of composite material.The results prove that St-ACR has obvious improved the comprehensive performance of the composites,the best adding quantity is 6wt %.