Research On Preparation Of Phosphate Esterified Starch Adhesive And Its Application In Building Materials

In this paper,the phosphate starch adhesive was prepared with wet method using phosphate as esterifying agent,which was applied in building materials,and industrial production test was carried out.The results showed that monometallic sodium orthophosphate was the best esterifying agent,the amount of esterifying agent,reaction temperature,pH and reaction time had some influence on phosphate starch.When the mass ratio of monometallic sodium orthophosphate to starch was 3:20,pH was 5.0,the reaction time was 20 minutes,the degree of substitution of phosphate starch was higher,the transparency and fluidity of phosphate starch adhesive obtained by sodium hydroxide gelatinization were significantly improved.In the inner wall putty that made of phosphate starch,the formaldehyde,benzene series,VOC,lead,chromium,cadmium,mercury and other toxic and hazardous substances content were in line with national standards limit,the application property,sanding property and other physical properties were also in line with industry standards.According to the test method of chemical reaction thermal effect,a method of testing the heat storage performance of non-uniform phase change material was designed.The Cp of the test device was tested through multiple measurements and the results showed that the average Cp of the test device was 347.14 J/K,the relative deviation was 1.9%,and the relative standard deviation was 2.6%.The method was applied to test phase change materials,which showed the heat storage value of the liquid microcapsule paraffin phase-change material was 61.36 J/g,the relative deviation was 0.8%,and the relative standard deviation was1.1%.The heat storage value of the powder microcapsule paraffin phase-change material was tested to be 158.19 J/g and the result of the DSC test was 156.50 J/g,the error was 1.07%.The method can be used to determine the heat storage performance of liquid or solid phase change materials and uniform or non-uniform heat storage particles,which deviation and error can be controlled within the range of less than 4%.The preparation of phase change thermal storage particles based on sodium sulfate showed that the dosage of Na₂SO₄·10H₂O,phosphate starch,super absorbent resin,water and gypsum all had a great influence on granulation and the properties of particles.When the mass ratio of Na₂SO₄·10H₂O to phosphate starch was 10:1,the viscosity of the material was suitable and easy to granulate.When the mass ratio of the total mass of Na₂SO₄·10H₂O,phosphate starch and water to super absorbent resin was 60:1,the phenomenon of phase separation wasn’t occur,and it was still stable after multiple cycles of heating.When the mass ratio of gypsum to water was 52:12,the effect of granulation was good and the rate of granulating was higher.The heat storage value of the base of sodium sulfate phase change heat storage particles was tested to be 31.22 J/g,the relative deviation was 2.1%,the relative standard deviation was 2.9%,the relative deviation between test results and the theoretical value of 32.50 J/g was 3.93%.The experimental results of preparing geothermal mortar with sodium sulfate based phase change heat storage particles,sand and cement showed that the compressive strength and flexural strength also kept changing with the increase of cement content.With the increasing amount of cement from 25%⁵2%,compressive strength was significantly increasing and then decreasing.When cement content was 43%,the maximum compressive strength was 24.5 MPa.When contents of cement increased from25%⁵2%,the flexural strength also increased first and then decreased.When the cement content was 40%,the maximum flexural strength reached 6.0 MPa,which can reach the national construction mortar standard requirement.Several products in this study can be widely used in schools,hospitals and other types of residential,which had good prospects for the application.