The Study Of New High Efficiency Self-concrescence Concrete Waterproofing Material Synthesis And Property

Concrete is a non-homogeneous porous material, there is a large number of micro-defects in its internal structure, these micro-defects expansion will become a channel for the latter part of the concrete seepage under certain conditions. As concrete waterproofing material, acrylic polymer emulsion,ethylene-vinyl acetate copolymer emulsion and epoxy polymer emulsion are commonly used in the field of construction, the mechanism of waterproof is that polymers can form impermeable polymer networks and polymer particles to block water seepage channels, but these polymer emulsions have a lot of defects, for example monomer expensive, high dosage, synthetic equipment and processes complication. Polystyrene is an oil-soluble polymer, and if the sulfonation degree and degree of neutralization are appropriate, it may be uniformly dispersed in aqueous solution without emulsifier, using as the concrete waterproofing material.In this paper, five different molecular weight of polystyrene were prepared from styrene by cationic polymerization and suspension polymerization, and their relative molecular mass was characterized by viscosity method and gel chromatography method. The high molecular weight Poly (calcium styrenesulfonate) (PCSS) which was water-soluble was prepared from polystyrene and sulfuric acid by suspension method and azeotropic distilation method, and its structure was characterized by chemical titration and 1H-NMR. Factors such as reactants ratio, temperature, solvent and time affected the degree of sulfonation of polystyrene were investigated,and the two methods were compared with each other; The five different molecular weight of PCSS affected the waterproofing properties of cement mortar and concrete were also investigated, in order to select the most suitable relative molecular weight of PCSS as concrete waterproofing material and the best concent in concrete.The results showed that:1. when the ratio of [AlCl3]/[St] in the range from 0.05 to 4.00, the molecular weight of polystyrene which was from 5000 to 30000 could be prepared by using cationic polymerization; When the ratio of [BPO]/[St] in the range from 0.3 to 0.4, the molecular weight of polystyrene which was from 207500 to 28600 could be prepared by using suspension polymerization.2. The sulfonation degree of polystyrene higher than 90%which could easily dissolve in water could be prepared in the case of a smaller amount of sulfuric acid by using suspension sulfonation method and azeotropic distilation method;The sulfonation degree was increased with an increase in the ratio(R) of sulfuric acid/polystyrene and reaction time. PCSS could be synthesized in the presence of equivalent amount of sulfuric acid by using azeotropic distilation method.3. When the relative molecular mass of PCSS was 163800,it was the most suitable for concrete waterproofing material; When the concent of PCSS was 0.01%, the effect of waterproof on concrete could reach the first-class standard, and the concrete also had the ability to self-concrescence.PCSS was firstly introduced to use as concrete waterproofing material,which was inexpensive and low dosage in concrete.When the PCSS was added into concrete,the concrete also had the ability to self-concrescence, and it had advantages in reducing the cost of polymer concrete waterproof material and expanding the application area.