Preparation And Properites Of Nano Carbon Black/Polystyrene Composite Microspheres

Polystyrene is the most commonly used thermoplastics.The excellent performance such as ease of processing and chemical stability and electrical insulation make polystyrene have extensive applications.However,poor heat resistance,easy aging and other shortcomings have limited the further application and development of polystyrene.Nano CarbonBlack has outstanding thermal stability and conductivity,it has a wide range of applications in the rubber and coatings industry.Meanwhile,nano carbon black also used as the nano fillers to modify the polymer conductivity,heat resistance and strength properties in the preparation of polymer composite materials.In this paper.CB/PS composite microspheres were prepared via in situ suspension polymerization using nano-carbon black as fillers and divinylbenzene as crosslinking agent.Simultaneously,PS microspheres were prepared by suspension polymerization using expandable polystyrene(EPS)and styrene.The main contents are as follows:Chapter one:CB/PS composite microspheres were prepared via in situ suspension polymerization using nano carbon black as fillers,DVB as crosslinking agent,BPO as initiator,TCP and PVA as complex dispersant.Experiment result showed that the addition of co-dispersant to the system could improve the dispersibility of nano-carbon black in the styrene when using the ultrasonic dispersion method.In the comparison of ultrasonic dispersion and mechanical dispersion,it was found that the dispersion time required for ultrasonic dispersion was short and the system was stable when dispersed.When the dispersants TCP was 0.2g and PVA was 0.1g,the reaction was carried out at 70-75℃ for 2h,80-85℃for 4h,90～95℃ for 2h,the microspheres had the best sphericity and the highest conversion rate.The thermal properties of the CB/PS composite microspheres have been discussed that the Tg of the microspheres was increased by 10℃ in the presence of the carbon black.The Tg of the composite microspheres also increased with the increase of DVB.The Tg of the composite microspheres increased by approximately 10℃ when the heat treatment conditions were heated at 195 ℃for 1 hour.The mechanism was analyzed by FTIR.The SEM photographs also showed that the nano carbon black could be uniformly dispersed in the polystyrene matrix.Chapter two:First,different concentrations of EPS were dissolved in styrene monomer to prepare EPS-St solution.Then,PS microspheres were prepared by suspension polymerization using BPO as initiator and TCP and PVA as dispersants.Experiment result showed that when tested for the viscosity of EPS-St solutions at different concentrations.It was found that when the concentration was greater than 25%,the viscosity of the solution increased abruptly.The results of GPC showed that the MW of PS microspheres increased and the MWD became wider,and two peaks appeared in GPC spectra.The results of DSC showed that the Tg of PS microspheres was increased after adding EPS,and the Tg increased gradually with the increase of EPS content.Tg increased by 4℃ compared with pure PS when the EPS content was 20%.Meanwhile,the TG resultsalso illustrated that the thermal decomposition temperature of PS microspheres increased by 6℃ after adding of EPS.Insummarywe not only improves the heat resistance of PS microspheres,but also recycles the EPS.