Research And Application Of The Thermoresponsive Hyperbranched Polymer

In this article we prepared the thermoresponsive hyperbranched polyethylenimine possessing a large amount of isobutyramide and amine groups (HPEI-IBAm). Nine saturated aliphatic acids including formic acid (C1), acetic acid (C2), n-pentanoic acid (n-C5), trimethylacetic acid (t-C5), hexanoic acid (C6), octanoic acid (C8), decanoic acid (C10), dodecanoic acid (C12) and hexadecanoic acid (C16) were used to measure their effects on the cloud point temperature (Tcp) of HPEI-IBAm in a mixture of H2O/DMF (v/v=9:1). For comparison, the effect of these aliphatic acids on the traditional thermoresponsive linear poly(2-dimethylaminoethyl methacrylate)(PDMAEMA) and poly(N-isopropyl acrylamide)(PNIPAM) was also studied. The influence of aliphatic acids on different thermoresponsive polymers was different. The aliphatic acids with shorter carbon chains (C≤8) increased the Tcp of HPEI-IBAm, and those with long hydrocarbon chains (C>8) depressed the Tcp. With respect of the linear PDMAEMA, all the aliphatic acids employed elevated its Tcp. The specific ranking of aliphatic acids in raising the Tcp of linear PDMAEMA was similar to that for dendritic HPEI-IBAm, but with a minor difference. In the case of the linear PNIPAM, the aliphatic acids with C≤6had almost no influence on the Tcp. Raising the carbon number to be8or higher leads to the obvious Tcp depression. The different effect of aliphatic acids on the phase transition of these thermoresponsive polymers was discussed, and it was mainly attributed to their structural and topological difference.Through modification of polymer composite with different particle size of gold nanoparticles, the protective layer can be formed in the outer layer of the gold nanoparticles, gold nanoparticles stable existence, and catalytic ability. We studied the influence of the temperature, and concentration of gold nanoparticles size, judge the different of the composite gold nanoparticle solution catalytic ability. Moreover, with the increase of temperature and concentration of the solution, the catalysis of gold nanoparticles composite solution ability can be improved.