Synthesis Of Hyperbranched PS And Hydrophilic Modify

Recent years, highly branched polymers have attracted significant attention due to the peculiar structures and unusual physical properties. It is known that branched polymer chains have no inter chain entangling, no crystallization, low viscosity, high solubility and well inter-liquation et al. when compared with linear chains of the same molecular weight. It's unique inside nanostructure which can chelated ion, adsorb micromolecule, and also can be used as micromolecular reaction's catalytic dot. Hyperbranched polymers are mainly applied in modifier for polymer blending, thoughener for thermosetting resin, modifier for polymer membrane, drug delayed released and drug carrier et al. various domain. Therefore it is of great significance to synthesize one hyperbranched polymer successfully. At present there are tow main synthesis approach of hyperbranched polymer: no controllable growth -one step method and step controllable growth- standard one step method. The one step method is the best polymerization in common use, and is also preferably mature method.The hyperbranched polymerization has no strict domination, and has no careful separation and purification.The production's molecular weight distribution is much wider. The DB of hyperbranched polymer is lower than the dendrimer. It doesn't have strict geometry outline when compared with dendrimer. The most important reason that hyperbranched polymer has developed quickly than dendrimer is its easier synthesis approach, which has no use for protection, is convenient for industrial manufacture, and has low cost . In this context, we adopt one step method, and have reported a procedure employing conventional free radical copolymerization and, in the presence of a chain transfer agent, such as a thiol to inhibit crosslinking . This allows for utilization of large amounts of cross-linker , thus producing hyperbranched polymers with high cross-link density, without the formation of gel. Finally, the shape of the branched molecule can mostly become sphericity when the DB is high enough. We can sulfonate the hyperbranched polymer to receive various functional material.Our context we have now undertaken a measurement of a typical solution free radical copolymerization of styrene(St) and divinylbenzene(DVB) in the presence of dodecanethiol (DDT), AIBN as initiator , under 65℃, N2 atmosphere. We prepare hyperbranched polystyrene (PS) using one step method without the formation of gel. Chain transfer agent makes the synthetic technics easier.These branched chains often contain a large number of reactive groups which may be useful for further reaction to produce an original product. Highly branched polymers in principle can be made either by condensation or by free radical techniques. We have now undertaken a measurement of a typical solution free radical copolymerization of styrene (St) and divinylbenzene(DVB) in the presence of dodecanethiol (DDT). The proportion of crosslinker and monomer can reach 0.9:1.0(mol). We gained a series of different DB polymer. Now there has no perfect standard to characterize the hyperbranched polymer. Here we investigate different proportional polymers'physical property, thermodynamic property and configuration. As a result we synthesize high branched polymer successfully.Gel permeation chromatography (GPC) indicates that we synthesize high molecule weight polymer. But molecule reaction is random in our synthesis approach, so the distribution of our production is much wider. Ubbelohed viscosity method testify that the polymer has lower viscosity than linear PS. Hyperbranched PS has higher solubility when compared with linear PS. Differential scanning calorimetry (DSC) indicates that hyperbranched PS has glass transition temperature (Tg) than linear PS, higher DB higher Tg. Sometimes the polymer has two Tg, and even no glass transition. Thermogravimetry analysis (TGA) investigates that hyperbranched PS has higher decomposed temperature than linear PS. Linear PS can decompose completely, but branched polymer can't at the same temperature, and DB increase decomposed temperature. Finally we sulfonate the highest DB polymer, and use FT-IR to characterize the sulfonation. The method of sulfonation to the hyperbranched only react exterior benzene but can't carry into farther reaction. The sulfonation of PS itself goes with crosslinking, so that the sulfonated production could only scatter in water but couldn't dissolve. The sulfonated production has sulfonic functional group, therefore we can make it into functional material.Hereon foundation, we use similar method to synthesize hyperbranched polymer. Half of the styrene was displaced by maleic anhydride, then prepared hyperbranched styrene- maleic anhydride (HSMA). The anhydride of the maleic anhydride can react to alcohol, amine and water et al. In this context, we graft methoxy poly (ethylene glycol) onto hyperbranched copolymers of maleic anhydride with styrene. Amphiphilic hyperbranched copolymers of maleic anhydride with styrene (HSMA-g-MPEG) have well hydrophilicity. FT-IR indicates that hyperbranched SMA was synthesized successfully, and successfully graft methoxy poly (ethylene glycol) onto hyperbranched copolymers of maleic anhydride with styrene. At the same time we confirm more ideal grafting condition and preferably react condition different in different ingredient. HSMA-g-MPEG can scatter in water and dissolve in alcohol. All in all, in this context we get a round estimate of synthesis and characterization of hyperbranched PS and sulfonation . Moreover, the results were more significantly for synthesis and characterization hyperbranched. Because of time, the farther study of hyperbranched styrene-maleic anhydride and HSMA-g-MPEG. Here we merely use FT-IR to characterize it. This field still has much research room.