Synthesis And Application Of Temperature-sensitive Polymer By The Change Of PH As Responsive Signal

In the study, pH change of glycine aqueous solution with temperatures was studied firstly. The results confirmed that pH responded to temperature, and the values decreased with the increasement of temperature. The pH response to temperature varied in different pH ranges of the aqueous solutions, and colors changed when acid-base indicators were added to the aqueous solution.Subsequently, a functional monomer, 2-(allylamino)-2-oxoethanaminium 2,2,2-trifluoroacetate, was obtained by the deprotection of tert-butyl 2-(allylamino)-2-oxoethylcarbamate, which was designed and synthesized from glycine and its ester through three different routes. The structures of the compounds were confirmed by 1H NMR and FT-IR. The optimal route was considered, and the total yield was up to 68%.And then poly(glycyl allylamide) was obtained by aqueous solution polymerization from 2-(allylamino)-2-oxoethanaminium 2,2,2-trifluoroacetate, and pH response to temperature of its aqueous solution was investigated. The results showed pH value of poly(glycyl allylamide) aqueous solution had different responsive properties to temperature, and this difference could be denoted with pH～temperature coefficient (dpH/dT). The polymer aqueous solution exhibited a positive dpH/dT when its pH was in the range of 5 to 7, while it showed a negative one when its pH values ranged from 8 to 10. But the dpH/dT is nearly zero in the pH ranged 7 to 8.Moveover, an abinitio application of the temperature-sensitive polymer was studied as thermochromic composites. Composites formulated from an aqueous solution of a temperature-sensitive polymer, poly (2-acrylamidoethanaminium chloride), and acid-base indicators were designed and prepared. The thermochromic composites underwent reversible color interconversion, and temperature range of color change could be tuned. The temperature range was governed from 0 to 100 oC by the modification of initial pH values and the colors could be changed by alteration of acid-base indicators. In addition, the stability studied here was measured over 50 days and high reproducibility confirmed.At last, a monomer containing p-aminobenzoic acid residue was designed and synthesized. Poly(4-(2-(methacryloyloxy)ethylcarbamoyl)benzenaminium chloride), a novel water soluble macromolecular UV absorbent, was obtained by solution polymerization from the functional monomer. Performances of UV absorption for the functional monomer and the polymer in aqueous solution were investigated. The experimental results show the monomer exhibits higher absorption efficiency than that of p-aminobenzoic acid in the ultraviolet B range (320nm~280nm), which is responsible for sunburn, photoinduced immune suppression and so on. In addition, the polymer synthesized from the monomer is also efficient to absorb ultraviolet rays although it possesses a little lower absorption efficiency and a notable blue shift.