Synthesis And Properties Of Polyacrylic Acid Thickener

Due to its biocompatibility, no-toxicity, and environmental friendship, slight crosslinked polyacrylic acid (PAA) thickener was potentially widely applied in biomedical application.In recent years, due to its high thickening ability, high conductivity, discharge properties and storage properties of batteries were greatly improved by slight crosslinked polyacrylic acid thickener, which attracted much attention from the public.However, synthesis methods and the process of polyacrylic acid have been reported rarely. Therefore, it is of great significance to study polyacrylic acid thickener with high thickening ability and the electrolyte-resistance properties.In this paper, we had synthesized polyacrylic acid thickener with high thickening ability and electrolyte-resistant property by aqueous solution polymerization and precipitation polymerization.(1)polyacrylic acid thickener synthesized by aqueous solution polymerizationSoluble N-maleyl chitosan(N-MACH) crosslinker with double bond was synthesized firstly with chitosan and maleic anhydride as materials.The structure of the products was characterized by hydrogen nuclear magnetic resonance spectroscopy (1H NMR) and infrared spectroscopy(IR), which showed that the structure of products obtained was in accordance with the theoretical molecular structure of the product.Polyacrylic acid thickener was synthesized by aqueous solution polymerization, using N-malely chitosan as crosslinker, acrylic neutralized by sodium hydroxide as raw material,ammonium and persulfate-sodium bisulfate(APS-NaHSO3) as low temperature initiator. The factors influencing the viscosity of polyacrylic acid such as neutralization degree, the amount of initiator and crosslinker were studied. The internal structures,the surface structures,and heat properties of the obtained products were characterized by IR, SEM and TGA.etc.Performance tests showed that:the viscosity increased with the rise of neutralized polyacrylic acid thickener,the two being roughly in a linear relationship.The viscosity of 0.5% neutralized polyacrylic thickener was up to 54.3 Pa·s;and the viscosity of 0.5% neutralized polyacrylic acid thickener added with 0.005 mol·L-1 NaCl was still up to 22.4 Pa-s;thickening ability and the electrolyte-resistance ability of 0.5% neutralized polyacrylic acid thickener improved more than 0.5% neutralized polyacrylic acid thickener crosslinked with N, N'-Methylene-bis-acrylamide (NMBA).(2) polyacrylic acid P(AA-co-ODA) thickener synthesized by precipitation polymerizationPolyacrylic acid P(AA-co-ODA) thickener with long-chain hydrophobic group was synthesized by precipitation polymerization, using stearyl acrylate as comonomer, acrylic(AA)as raw material,hypermer B-246 as non-ionic dispersant, azo-bis-iso-heptonitrile (ABVN) as initiator. The major influencing factors and reaction conditions to prepare thickener had been studied particularly by orthogonal design,ideal synthesis process was gained by single factor analyzing. The internal structures, the surface structures, and heat properties of the obtained products were characterized by IR, SEM and TGA.etc.Performance tests showed that:neutralized polyacrylic acid thickener displayed the properties of plastic fluid rheological properties in non-newtonian fluid,the viscosity increased with the rise of polyacrylic acid thickener. The viscosity of 0.5% neutralized polyacrylic acid thickener was up to 110 Pa·s, and its clarity was up to 96.3%.The viscosity of 0.5% neutralized polyacrylic acid thickener added with 0.005 mol·L-1 NaCl was still up to 41.2 Pa·s.Alkaline electrolyte of polyacrylic acid solution showed high conductivity.