Properties And Microstructure Of PB-g-PS Cement Modifier Modified Cement Mortars

In the paper,polybutadiene grafted polystyrene emulsion(PB-g-PS)was synthesized by half a batch emulsion polymerization.The mass ratio of polybutadiene(PB)to polystyrene(PS)is 90/10,80/20 and 70/30,and the twain-20 of 5% of the latex solid mass was joined into,the PB-g-PS cement modifier(SBCM)was prepared,and it used to modified cement mortar,the influence of SBCM on cement hydration was investigated by using FTIR and DSC,the following four aspects of the work:1.In the fixed flow of 175 ± 5mm,and water curing metheds.This study investigates the influences of weight ratios of polybutadiene to polystyrene and the polymer-cement ratios on the flow,water reduction effect,compressive and flexural strength and water absorption rate of SBCM modified cement mortar.The empirical data show that the three kinds of SBCM have good water-reducing effects and can significantly reduce the water absorption of modified cement mortar.The maximum of water reduction rate and water absorption rate are 56.7% and 0.288 kg/m2 respectively.The addition of cement modifier also has an important effect on the mechanical performances of modified mortar.The flexural strength of some modified mortar was improved,and the maximum of flexural strength is 8.1 Mpa,and the compressive strength was reduced.2.The SEM was used to investigate the microstructure of the modified mortar.It can be seen that the hydration products are closely bound with dense structure in the modified mortar by the scanning electron microscope.The cherry beam and cone shaped particles,latex particles and latex film of different shapes,dendritic structure and composite structure in the modified mortar were observed.These structures have important effects on the properties of cement-based materials.3.The influence of SBCM content on cement hydration was studied by infrared spectroscopy and differential scanning calorimetry.The experiments results findings that the degree of cement hydration increases with the content of SBCM,and the hydration degree of cement is the highest when SBCM content is 10%.