The Kinetic Of Functional Reaction Of Hyperbranched Polymers

Recently, dendritic and hyperbranched polymers, have been attracted considerable attention due to their highly branched units with peculiar properties, such as low melt viscosity, dissolubility, non-entanglement and a large number of end groups. Hyperbranched polymers were widely used in many fields, such as functional materials, clinical medicine, supramolecular chemistry, biochemistry and pharmaceutical industry. In this paper, two kinds of hyperbranched polymers were synthesized, in which one is the AB2 type hyperbranched poly(amine-ester) with end active hydroxyl group, and other is the A2-B4 type hyperbranched polyester with end active carhoxyl group, and were characterized by GPC DSC TG.FTIR techniques. The reaction kinetics of the active end groups was studied to obtained some interesting results, where the deviation from the second order reaction (or the first order reaction) scheme was observed. The anomalous diffusion theory is applied to this reaction system to give the phenomenological equation of reaction kinetic, which can be used to describe the experimental results. The theory results are agreement well with the experimental dates. The reaction discussed in the paper may be served as the basic model in many intensive research fields, such as biochemistry, chemical engineering, clinical medicine, and so on. Sec. I of the paper gives the review of hyperbranched polymer and the diffusion of the small molecule in polymer solution. In Sec. II of the paper, the AB2 type hyperbranched poly(amine-ester) with end active hydroxyl group is synthesized, and was characterized by GPC. DSC TG. FTJR techniques. The reaction of end active hydroxyl groups with acetic oxide was studied in detail to obtain the deviation from the second order reaction, where the influence of the concentration, molecule weight of hyperbranched poly(amine-ester), reaction temperature and stifling effect was examined to give some interesting results. The 77 4 deviating degree from the second order reaction was increased as the concentration of hyperbranched poly(amine-ester) increasing, and decreased as the reaction temperature increasing. If the stirring rate is high enough, the reaction scheme was return to the second order reaction. In order to give the interpretation of the experimental results, phenomenological equation, according to the anomalous diffusion theory, was proposed to derive the relation between the conversion of molecules with the reaction time. The above results agree well with the experimental dates. In Sec. III of the paper, we focused our attention on the reaction kinetics of carboxyl group on A2-B4 type hyperbranched polyester with epichlorohydrin to give the similar results as that of above section was obtained. All results obtained in the paper should be implied that the kinetics of functional reaction of active end groups on hvperbranched polymers should have some deviation from classical reaction. The phenomenological equation derived according to the anomalous diffusion scheme may be served as the basic model in other scientific fields such...