Preparation And Characterization Of Waterborne Polyurethane Modified By Fluorine/Silicone

With the development of the enviroment protection rules,chemical industry also full of challengs. Waterborne polyurethane is one kind of green polymer materials,more addition, waterborne polyurethane is famous for its machanical properties and wearability,so,it must be the development direction on future. Waterborne polyurethane uesed water as dispersion medium.The water resistsnce of this materials with prepared by self-emulsification mrthod allows a discount because of introduced hydrophilic groups. Improving water resisitance has been urgent affairs,introduced atom with low surface energy such as silicon atom,fluorine atom were be as the primary ways to improve water resisitance.In this article,we made introducing ailicon and fluorine atom as main line,hope to increased water durability of waterborne polyurethane.In the study,silicone atom exsting in hydroxyl-terminated siliscone-polether with trifunctionality was introduced in polyurethane as one kinds of polyether,meanwhile,crosslinking drgree in our systerms was increased.Fluorine existing in mono-slcohol was terminated with isocyano.A series of waterborne polyurethane latex and their films were prepared.The relationship between stucture and properties was analysis detailedly.The modification mechanism was discussed.In first chapter, waterborne polyurethane properties and development on improving water resistance at home and abroad were reviewed.The relationship and difference among these methods as well as prepration mrthods were summarized.In the second chapter, the preparation methods on waterborne polyurethane modified by polyurethane silicone oil was introduced.The modifier was hydroxyl-terminated siliscone-polether with trifunctionality. Subsequently,making aboved emulsion as seed-emulsion, polymerization occurred after adding acrylic monomer. Based on synthesis technology, SPUA latex and films were charaterized by means of infrared spectrum(IR), transmission electron microscopic(TEM), thermogravimetric analysis(TG), differential scanning calorimetry and so on. the results showed that core-shell structure had formed between polyurethane and acrylate. After modifed by silicone and acrylate,the thermal stability of polyuretane was improved obviously. High compatibility has been embodyed. Indeed, silicone tended to transferred to film surface in the film formation process.Two urethane acrylate polymerization methods were compared,which were monomer dropwising method and monomer pre-emulsion method.It can be showed that better product results can be obtaine by monomer pre-emulsion method.In the third chapter, A novel kind of fluorinated waterborne polyurethane was resreached. Fluorine groups were integrated with polyurethane main chains uesed monocarboxyl fluorocarbon chain as fluorinated modifier. Fluorinated waterborne polyurethane containing ionic in soft segment was obtained,which used method of molecular design.. The properties such as synthetic method,water assistance, thermal stability and crystallinity of conventional waterborne polyurethane, Fluorinated waterborne polyurethane containing ionic in hard segment, Fluorinated waterborne polyurethane containing ionic in soft segment were comparied. The structure of fluorinated waterborne polyurethane was determined and the infulence of fluorine groups on hydrogen bond between soft segment and hard segment was informed by infra-red spectrum.The water contact angle was increased from 73°to 107°with the fluorine groups increased. Water absorption was reduced by 66%, water resistance of polyurethane was increased. The themogravimeotry analysis results indicated that the max loss temperature of polyurethane glue film was increased by 30℃,so thermal stability was improved. wide-X-ray diffraction and scanning electron microscope of fluorinated polyurethane showed that multiphase structure was existence in fluorinated polyurethane,the crystallinity of fluorinated polyurethane glue film was increased the crystalline form was slightly changed.This chapter also compared two flourintated technology. One is the conventional flourintated urethane acrylate polymerization technology which flourine modifier is flourintated acrylate.The other our flourintated polymerization technology which flourine modifier is flourintated end capping reagent. It can be conclued that our flourintated polymerization technology possess more solvent resistance, simpler polymerization technology.The flourine was at the end of the chain,,more unrestrained of flourine was obtained.