Synthesis And Properties Of Sodium Polyacrylate Thickener For Cosmetics

As an effective thickener with high molecular weight,sodium polyacrylate can improve the viscosity of the system, change the product flowing form, and enhance the stability of the system. It is widely used in food,paint, adhesives, cosmetics, detergents,printing and dyeing, rubber,medicine and other fields. Therefore, strengthening the research of methods and application of synthetic sodium polyacrylate thickener is of great significance.In this paper,15# white mineral oil as the continuous phase, acrylic as monomer, water as a medium, SpanSO as emulsifier, N,N’- methylene bisacrylamides as crosslinking agent,azobis isobutyl hydrochloride as initiator in sodium acrylate inverse emulsion polymerization, and the impact of the polymerization temperature, stirring rate,selection and amount of initiator, selection and amount of emulsifier, amount of crosslinking agent, as well as the the amount of monomer and the degree of neutralization for the polymerization process and the product thickening ability were studied, and get the optimal synthesis conditions, when 70% the degree of neutralization, 20wt% monomer,2wt% emulsifier, 0.03wt% initiator dose,0.03wt% crosslinking agent,under temperature programmed from 30。C to 70。C, we can get a high thickening properties of sodium polyacrylate thickener, it’s viscosity of 0.5% active substance is SOOOOmPa-s. The experimental materials are cheap and easy to get, process conditions are simple, safe, easy to control and easy to implement,it has important guiding significance for the industrial mass production.By the measurement of product’s solid content, IR spectroscopy, particle size distribution, liquid chromatography and K value, we studied the structure, particle size, residual monomer and molecular weight of the resulting sodium polyacrylate emulsion. The paper also focused on exploring a method for determining residual acrylic monomer and reducing residual monomer: the sample by adding acid and filtration pre-treatment to reduce the viscosity of the testing solution and the content of large particles,to ensure that we can use liquid chromatography to test the thickener’s monomer residue; and by adding reactive initiator in later reaction can achieve the final product monomer residue is zero. The article also measured the K value by ubbelohde viscometer to characterize molecular weight and the average degree of polymerization of the polymer.By measuring the product viscosity under different conditions, we studied the viscosity changes of sodium polyacrylate in different electrolyte content, different pH, different temperatures, and different solvents. The results showed that sodium polyacrylate thickener viscosity under different conditions changes little by the electrolyte, pH, temperature and solvent. By comparison with the France Seppic305 thickener, it shows that two quite thickeners have similar thickening properties, our product has good practical value. The paper also studied the sodium polyacrylate thickener used in cream formulation and heavy oily cream formulation, and testing the appearance,use, security, and stability of the resulting product. The results showed that the addition of the product obtained white, bright,consistency, suitability,smear and spread good paste, it is a efficient thickener in cosmetics.