PH changes as a response signal to the temperature-sensitive polymer synthesis and application of
|School||Hefei University of Technology|
|Keywords||Glycine Polyacrylamide ethylenediamine dihydrochloride PABA Thermosensitive pH Acid-base indicator|
This paper studied the small molecules of glycine pH of the aqueous solution with temperature variation. The results show that glycine solution pH is reduced with increasing temperature, and in a different pH range, pH, degree of variation with temperature is different. Glycine in a solution of pH by adding the appropriate acid-base indicator, the color can be achieved with the solution temperature changes. Subsequently, glycine as the starting material, was designed and synthesized functional monomer - glycyl allylamine trifluoroacetate. The monomer is stripped by trifluoroacetic acid Boc-glycyl-allyl amine protecting group obtained, but Boc-glycyl-allyl amine synthesis route is the use of three were treated with glycine methyl ester and N- hydroxysuccinimide active ester obtained. Experiments, the use of nuclear magnetic resonance (1H NMR) Synthesis of a new product characterized by a structure, and wherein the analysis and optimization of a synthetic route, the optimized functional monomer total yield 68%. Then glycyl allyl amine trifluoroacetate by solution polymerization, through a series of purification and treatment, to obtain glycyl poly allyl amine, and the effects of newly synthesized thermosensitive polymers. The results showed that the pH of the polymer solution has a temperature-sensitive, and in the different pH environments, different sensitivity. Wherein the pH is 5 to 7, pH, and increased with increasing temperature; the pH of 8 to 10, pH value decreased with increasing temperature; solution pH of 7 to 8, pH, basic does not change with temperature. The temperature coefficient (dpH / dT) that can be obtained with the temperature coefficient of the solution pH of the solution to achieve a shift from positive to negative. Further investigated the application of temperature-sensitive polymer. Thus, the design and preparation of polyacrylamide ethylenediamine hydrochloride and acid-base indicator mixed solution and a mixed solution of thermochromic properties. Studies show that the mixed color of the solution changes reversibly with temperature; mixed solution by adjusting the pH of the initial solution can be adjusted to change color temperature, the temperature adjustment range of 0 ~ 100 ℃; also be a method by adding various changes indicator solution color. Experiments show that the solution has a high repeatability, stability up to 50 days. Finally, p-aminobenzoic acid as starting materials, synthesis of a novel water-soluble monomer 4 - (2 - (methyl methacrylate) glycyl ethyl) aniline hydrochloride, after the water-soluble radical polymerization macromolecular ultraviolet absorber poly-4 - (2 - (methacrylate) glycyl ethyl) aniline hydrochloride. The water-soluble monomer to UV B has significant absorption effect, the same concentration, and its UV absorption capacity of 2.0 times of the amino acid; the monomer molecules can be obtained by ultraviolet absorption wavelength shorter (blue shift), but its ultraviolet absorption capacity than the monomer decreased for 85% of the amino acid, but still has a high ultraviolet absorption efficiency.