Synthesis By Electronic Beam Irradiation And Characterization Of Polystyrene/ Exfoliated Graphite Nanosheet Composite

Polymer/inorganic layered nanocomposites have attracted great attention because of the obvious properties improvement (such as heat-resistance, barrier property et al) caused by the introduction of nanolayers. Exfoliated graphite(EG) is a class of synthetic layered nano-materials, which can be used to form nanocomposites with polymer. Due to the functional properties, the polymer/EG nanosheet composites have a bright prospect in many fields. Compared with traditional chemical method, radiation technology has advantages such as low energy consumption, clean and environmental protection in polymer preparation.The new methods for preparing polymer/EG nanosheet composites by high electronic beam irradiation were investigated using PS as a representative in this thesis. The structure and properties of the resultant PS/EG nanosheet composites were characterized.1. Polystyrene/exfoliated graphite nanosheet composites are synthesized by the electronic beam irradiated polymerization with the post polymerization for the first time through specifical manufacture craft. Images of SEM and TEM show that the EG nanosheets are well dispersal in the PS matrix with the thickness of 30～80nm forming a special network. The IR and XRD results show that the PS has intercalated the nanosheets, forming a layered composite.2. Studying temperature, time and irradiation dose to come together with the polymeric conversion, it shows that the conversion rate enlarges obviously along with the exaltation of temperature to come together horary extension behind. At 105℃, conversion can attain to over 90% after polymerizing for 10 hours, which shows that styrene have very high activity after irradiation. But in the scope with 8~22 kGy, the irradiation dose have less influence on the conversion rate. 3. With the different of irradiated dose and content of EG, the properties of electricity, thermodynamics and mechanics have been studied. The percolation threshold of nanosheet composite was 2.1wt%.The conductivity reached 10-2S/cm at a EG content of 10wt%, which confirmed that the composite has a good electrical conductivity. The decomposable temperature reached 478.7℃, which is 57.4℃higher than the pure PS. This shows that the composite has a improved heat-resistance comparing to pure PS.The tensile strength decreases, while the impact strength increases with the content of EG being lower than the percolation threshold. When the content is higher than that, the tensile strength has been increased firstly and decreased latterly. The impact strength has decreased all along. The best integrated property of the nanosheet composite has been attained when the content of EG is 5wt%. The irradiated doses have little effect on the property of the composite with the dose from 8kGy to 22kGy.