The Nano-materials Modified Polymer/Sulphoaluminate Cement Composite Coatings

The surface protection of concrete buildings is one of the important ways to improve its durability.Waterproof coating is also an important method for building surface protection.With the improvement of the performance requirements for building surface coating,it is urgent to develop a new type of waterproof coating.Polymer cement-based waterproof coating?PMCC?is a promising type of waterproof material,due to its composition of organic polymer and inorganic cement-based material composite,it has good durability,high mechanical strength such as cement-based material and high elastic and toughness such as polymer.In addition,based upon the unique properties of nanomaterials,nano-modified PMCC has gradually become a research hotspot.However,due to the complexity of the components,the relationship between its composition,structure and performance has not yet been clarified.This dissertation aims to improve the physical properties of PMCC and assign its functional properties.Also the effect have been made to study,the optimed composition of the PMCC,the structure-activity relationship and the modification effect of nano-TiO₂?TiO₂?.The research also includes the study of double-layer photocatalytic composite coating system and superhydrophobic composite coating system.The main results are listed as follows:?1?Appropriate PA/VAE latex ratio,polymer-cement ratio,fillers and admixtures?dispersant,defoamer and TEXANOL?can effectively increase the tensile property of coatings and reduce its water absorption.As PA/VAE latex ratio is 65:35,the polymer-cement ratio is 1.1,the filers-cement ratio is 2:3,and the content of dispersant,defoamer and TEXANOL is 0.3%,4.5%,and 3%,respectively,the coating is optimal.?2?Incorporation of proper amount of TiO₂ can effectively improve the rheological properties,mechanical properties,waterproof properties and durability of the polymer cement-based waterproof coating.And it can make coatings have a certain photocatalytic property.As the content of TiO₂ is 0.6%,the thixotropy of the coating is optimal;the bond strength and tensile strength of the coatings was increased by 59.0%and 15.0%.They reached to 2.8Mpa and 2.9Mpa respectively.And the photocatalytic performance of coatings is good at the same time.The degradation rate of RhB solution reached 38.5%.The durability of the coatings was good.The loss rate of tensile strength and elongation at break after UV aging reached the minimum,which were 24.33%and 19.47%.They were reduced by 55.95%and56.76%respectively.?3?The TiO₂ loading on the porous material can effectively improve the photocatalytic property of the coatings.The optimal loading of TiO₂ on bamboo charcoal and aerogel is 3%and 6%respectively.And the RhB solution is degraded for 4 hours by 62.9%and 82.0%,which were higher 43.7%and 62.8%than blank TiO₂ respectively.Pore structure analysis showed the TiO₂/bamboo charcoal?TiO₂/BC?and TiO₂/aerogel?TiO₂/AG?reached 388.33m²/g and 989.11m²/g,which increased by 43.10m²/g and 106.37m²/g respectively.SEM analysis showed that the TiO₂ particles mainly distributed on the edges and surfaces of macropores on the surfaces of bamboo charcoal and aerogel without blocking the pores of the pores itself.?4?Photocatalytic porous material can effectively improve the mechanical properties of the PA coating and make the coating have a good photocatalytic property.As the TiO₂/AG content increases from 0%to 10%,the pencil hardness of the coating increases from 1H to 2H;the impact strength increases from 42kg.cm to 51kg.cm.As the content of TiO₂/BC and TiO₂/AG was 6%,the photocatalytic property of the coatings was the highest,and the degradation rate of RhB reached 83.7%and 88.0%.?5?As MTES is not modified nano-SiO₂ sol-gel,the coating is in accordance with Wenzel model.With the increase of MTES content,the hydrophobic model of coatings is gradually transformed from Wenzel model to Cassie model.?6?The appropriate amount of FAS can effectively improve the superhydrophobicity of nano-SiO₂ sol-gel.As the amount of FAS is 3%,the super hydrophobicity property of the coating is the highest,and the wetting angle reaches the maximum value of 166.44°,which is 16.94%higher than that of the blank sample.?7?The polymer cement based composite functional waterproof coating prepared in this paper satisfys the national inspection standards for exterior wall coatings?GB/T 9755-2014?.