| Polyacrylic acid thickener is a kind of efficient thickener developed in recent years.Its thickening effect and comprehensive properties are good,and it can achieve the purpose of thickening quickly.And the dosage is small,the cost is low.Different kinds of polyacrylic acid thickeners are widely used in printing,coating,daily chemical,medicine,food and other fields.However,in textile printing and dyeing,such thickeners still have some problems,such as poor electrolyte resistance,poor thixotropy of color paste,etc.And in the process of use is easy to be affected by many factors,the effect is not stable.The subject optimized the polymerization process of polyacrylate thickener through the method of system temperature rising,the starting temperature of the system,the total amount of emulsifier,the amount of initiator and the ratio,the duration of heat holding in the later stage of reaction,the amount of phase converter,and the selection and study of solvent medium.The modified monomer polycarboxylic acid was selected,the neutral monomer was studied,the ratio and dosage of long chain alkyl monomer were changed,and the formulation of polyacrylate thickener was optimized.The effect and significance of adding different monomers were investigated,and the best synthesis technology and formula of polyacrylate thickener were determined,and an associative polyacrylate thickener with good salt resistance and comprehensive performance was obtained.In addition,the properties of polymer emulsion were evaluated by viscosity,viscosity rheological index(PVI)and viscosity retention.The structure of the polymer was characterized by Fourier transform infrared spectroscopy(FT-IR)and particle size analysis.The application performance of thickener was tested and evaluated by water retention value,water retention,color giving capacity,back permeability and heat resistance stability.The experiments show that the temperature of the system is raised by parabolic heating process.When the initiation temperature of the system is about 50?,the reaction temperature is more controllable,and the reaction is more stable and mild.The addition of a very small amount of trans cinnamic acid can inhibit the temperature rise of the reaction system,which can be used in large-scale production to make the temperature rise of the system easier to control and the reaction more moderate.The relative contents of acrylic acid(AA),methacrylic acid(MAA)and hydroxyethyl acrylate(HEA)were 83%,12% and 5%,respectively.The amount of modified monomers octadecyl acrylate(SA),acrylamide(AM),N,N methylene bisacrylamide(MBAM)was 1%,2.13% and 0.13% of the total monomer,respectively.The amount of emulsifier was 11.38% of the total weight of the monomer,and the ratio of pan 40 to pan 80 was 2.33:1.The stabilizer polyethylene glycol 400 monooleate(R3)accounted for 0.28% of the total polymerization monomer.The chain transfer agent dodecyl mercaptan(TDDM)accounted for 0.04% of the total polymerization monomer.The mass ratio of ammonium persulfate(APS)to sodium bisulfite(SHS)was 2.52:1,and the total amount of initiator was 0.39%.The phase transfer agent isomeric tridecanol polyoxyethylene ether(1312)accounted for 7.74% of the total polymerization monomer.When the solvent dosage of the system is 260% of the polymer monomer and the ratio of deionized water to kerosene is 1.44:1,the thickening property of the product is better.However,the composite of polyacrylate thickener and polyurethane thickener can improve the formation rate of white paste to a certain extent,but the comprehensive analysis is not good for the improvement of printing performance. |
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