Study On Gelatination And Micellization Of Amphiphilic Copolymers

Amphiphilic linear polymers and gels were prepared by macromonomer technology. The structure and properties of these polymers were studied. Amphiphilic temperature-sensitive gels composed of FA and MAA were synthesized by dispersion polymerization in the mixture of ethanol and water. The effect of different crosslinking degree on the gels' upper critical solution temperature (UCST) was studied. The influence of the ratio of mixed solvents, the temperature of the system and the pH value on the gel's swelling ratio (SR) was investigated. The experiment result indicated that with the increase of ethanol content in mixture of ethanol/water, the SR of gels increases at first then decrease, and the SR of gels increases with the increasing of temperature. Other wide, the gels have the pH-sensitive ability. The amphiphilic copolymer PAFn and copolymer PPMAFn with temperature-sensitive property were synthesized by free radical polymerization. The thermal behavior of these copolymers was characterized by DSC, and the result indicated that the glass transition temperature (Tg) of the copolymer decreased with the increasing of FA content. A series of micelle solutions were prepared in selective solvents by means of self-assembly. The results of spectrophotometer showed these copolymers have thermosensitive property in ethanol/water mixture, they have an apparent phase-transition phenomenon at the Upper Critical Solution Temperature (UCST). Furthermore, the effects of the concentration of polymer solution, the ratio of selective solvents, the ratio of monomers, the n value of monomer FAn on the sizes of micelles were studied.The modifier 2-Hydroxy Propyl Acrylate(HPA) was grafted on Hydroxyethyl Cellulose(HEC) by using cerium ammomium nitrate/disodium ethylendiamine tetracetic aicd(CAN/EDTA) redax system as the initiator. The grafted copolymer was characterized by IR. The influence of ratio of HEC and HPA, the initiator content, reaction temperature and reaction time on grafted copolymerization were studied and the optimal formula and technology were determined by the means of orthogonal experiments. Then the single factor experiments were carried out, though which the effects of the concentrations of CAN,EDTA,HPA, polymerization temperature and time on the grafting reaction were investigated in terms of the grafting percentage(%G) , grafting conversion(%C) of the monomer and grafting efficiency(%E). The core-shell structure micelles can be formed by self-assembly of the graft copolymer in selective mixture solvent of water/acetone. The influence of the monomer, the ratio of water and acetone on the micelle size was investigated by dynamic laser light scattering.