三聚氰胺及其衍生物改性聚氨酯的制备与研的究-化学工程专业毕业论文.docxVIP

AbstractAbstract Abstract Abstract As the state began to limit VOC emissions，the waterbome polyurethane began to usher in a new development opportunities．Waterborne polyurethane has many advantages，such as，no pollution，excellent mechanical properties，safety，easy modification and good biocompatibility，etc．However，water resistance and poor heat resistance of the traditional waterborne polyurethane is not is not satisfactory， mechanical strength should be improved，which partly limited application and promotion of the waterborne polyurethane，modified WPU materials is widely studied． Common methods of modified polyurethane are physical blending grafting， nanomaterials modification or crosslinking modification．Melamine is a trimer of cyanamide，、ⅣitIl conjugated triazine ring，is stability at room temperature，诵th excellent heat resistance，will release a lot of nitrogen when the resin is made by its thermal decomposition，which Can be used as a flame retardant．Melamine has a unique stable triazine ring structure and three allelic primary amino group．、析tll considerable activity which Can be reacted with isocyanates and directly introduced into the polyurethane chain．Isocyanate Can reactive witll hydroxymethyl which is the reaction product of melamine and formaldehyde，while high etherified melamine formaldehyde resin as a crosslinking agent widely used in water—based paint，which Can cross—linking react with the anionic polyurethane，in order to achieve the purpose of modified cross-linking polyurethane，this paper modified polyurethane following three parts： (1)Preparation and characterization of modified melamine crosslinking waterborne polyurethane． Melamine as a crosslinking agent to modify WPU、析tll two methods melamine modified polyurethane and urethane-modified rear diffuser，compared WPU诵m the same degree of cross—linked by TMP，the results show that ATR found melamine crosslinking modified WPU、丽th expansion reaction is not complete；residual melamine did not participate i