Synthesis Of Temperature-sensitive Polymer And Its Application

Poly(N-isopropylacrylamide)(PNIPAAm) in aqueous solution is well-known to exhibit a thermoreversible phase transition at 32℃.This transition temperature is called a lower critical solution temperature (LCST). Below the LCST, this polymer is water-soluble and hydrophilic, existing in an extended chain form. PNIPAAm undergoes a reversible phase transition to an insoluble and hydrophobic aggregate above the LCST. This character of PNIPAAm has been widely used in the field of biological and medical science, such as the stability of enzyme, temperature control drug release.In this thesis, it mainly discussed the synthesis of binary linear copolymers PNIPAAm-IDA, its properties and application in environmental analysis .The main contents were shown as follows:(1) Binary linear copolymers, PNIPAAm-IDA was prepared by radical copolymer -rization with N-isopropylacrylamide(NIPAm) and iminodiacetic acid (IDA), and its pH and temperature responsive properties were investigated. Monomer's compostions in copolymers were characterized using infrared spectroscopy method.(2) The decolorization efficiencies on simulated basic fuchsine dye wastewater with linear copolymers PNIPAAm-IDA were studied. Factors that influenced the treatment such as pH value, its dosage and dye concentration were studied. The optimal treatment conditions were obtained. The results showed that when the concentration was lower than 50mg/L(the chroma is 16000),pH value was 3.0 and its dosage was 0.5%, the rate of decolorization was more than 95%.(3) The concentration of heavy metal ions in water using thermoresponsive polymer PNIPAAm-IDA was studied. The result indicated that it had obvious concentration effect: The hydrolysis of these metals was suggested in the pH range of 2.5 to 4.5. The concentration yield rapidly increased with a little increase of pH. When pH value was 4.0, the concentration yields of Co²⁺ and Cu²⁺ were more than 80.4% and 86.7%. And their concentration dosages were 1.61 mg/g and 1.73 mg/g, respectively.