Study On The Synthesis And Performance Of Polystyrene/carbon Black Composite Particles

Polystyrene is a kind of functional polymer material with excellent properties,such as good electrical insulation,low water absorption,good processing performance,high transparency etc,which was widely used in construction,packaging,automotive,electronics and so on.According to the properties and uses of polystyrene,it is divided into three categories: general purpose polystyrene(GPPS),high impact polystyrene(HIPS)and expandable polystyrene(EPS).In this paper,polystyrene(PS)particles and polystyrene/carbon black(PS/CB)composite particles were synthesized by suspension polymerization.Moreover,the modification of CB was studied.Further,the effect factors on polymerization,along with processability,thermal stability and particle size distribution were investigated,which could provide experimental basis for industrial production of expandable PS and PS composite particles.In this paper,PS particle was synthesized by suspension polymerization with benzoyl peroxide as initiator,polyvinyl alcohol/hydroxyapatite(PVA/HAP)as mixed dispersant,sodium dodecyl benzene sulfonate as additives under a certain temperature and stirring speed condition,and the effects of dispersant,initiator,temperature and stirring speed on the molecular weight,particle size distribution and thermal stability of polymer particles were discussed.The experimental results showed that the dispersant could effectively control the particles size and distribution.Temperature and initiator had a great influence on the polymerization reaction time,molecular weight,the distribution and mechanical properties of the polymer.The polymer with uniform particle size could be obtained by controlling the stirring speed,and finally the yield of particles more than 90% with the polymer particle size of about0.6-1.4mm could be obtained by controlling reaction conditions.Carbon black particles consisted of polycyclic aromatic hydrocarbon is similar to graphite,which possesses good heat-resistance,reinforcing,flame retardancy,conductivity,etc.However,CB particles had larger the surface area and are easy to aggregate,which resulted in poor stability of CB dispersed in the polymer matrix.In addition,the surface of CB particles bearing some inhibiting groups(for example,quinonyl,etc)could capture free radicals in the course of polymerization,which resulted to prolonging reaction time and poor polymerization result.Herein,in order to improve polymerization reaction surface modified using oleic acid adsorption and inorganic acid oxidation method.CB after modification was characterized by FT-IR,XPS,SEM,TGA.The PS/CB composite particles was synthesized basing on the synthesis of PS suspension polymerization.The effect of initiator and polymerization time on the polymerization reaction were discussed.The dispersion stability of the modified carbon black(MCB)in the monomer of polymer particle,limiting oxygen index,heat resistance,and particle size distribution was discussed.The results showed that the addition of MCB could shorten the polymerization time,improve the dispersion stability of carbon black in the polymer matrix compared with original CB,and finally obtain PS/MCB composite particles with uniform particle size distribution and better performance.In conclusion,PS and PS/MCB composite particles were synthesized by suspension polymerization.The effect of carbon black modification,the influence factors of polymerization,the mechanism of polymerization and properties of polymer were discussed and analyzed,which provided experimental and theoretical basis for industrial production of expandable polystyrene and composite particles.