Preparation Of PH Sensitive Waterborne Hyperbranched Polyurethane And Modification Of Polyimide

The hyperbranched polyurethane?HBPU?structure contains both hard and soft segments,and has a large number of end groups,so the performance of HBPU is adjustable and the modification is easy,and it has wide application prospect in all aspects.The synthesis of novel and functionalized HBPU has become one of the research directions of polyurethane resin,especially the waterborne polyurethane resin with environmental advantages.In this paper,the synthesis and modification of polyurethane,waterborne polyurethane,hyperbranched polyurethane,the application of polyurethane and pH sensitive polyurethane were introduced in detail.N,N-two hydroxyethyl-2-amino hydroxyl ethyl propionate?HAHEP?containing three hydroxyl groups was prepared by michael addition reaction using diethanolamine and hydroxyethyl acrylate as raw materials.The A₂ macromonomers with isocyanate groups were prepared by using toluene diisocyanate?TDI?,polycarbonate diol1000?PCDL1000?and 2,2'-dimethylol propionic acid?DMPA?.Preparation of new waterborne hyperbranched polyurethane?WHBPU?by A₂+B₃ method.The structure of B₃monomer and WHBPU was analyzed by FT-IR and ¹HNMR,The waterborne hyperbranched polyurethane?WHBPU?was characterized by thermogravimetric analysis?TGA?,differential scanning calorimetry?DSC?,water absorption,transmission electron microscopy?TEM?,particle size analysis?PCS?,cytotoxicity,pH sensitivity.It was found that the WHBPU had good stability.When the content of DMPA reached 40%,the WHBPU had the smallest hydration particle size,but the particle size distribution was wide.Water absorption of the film is high,indicating good hydrophilicity.In the case of NCO/OH=3:1,the WHBPU has two glass transition temperatures?Tg?,indicating that the microstructure of the hard and soft segments of the hyperbranched polyurethane structure.The WHBPU have a high cytotoxicity when the concentration of the waterborne hyperbranched polyurethane is greater than50ug/mL,but the WHBPU have good pH sensitivity and when the pH is changed from 7 to 5,the rate of change of particle size is more than 10%.This is beneficial to the biological application of WHBPU.Because the stability of the above WHBPU has reached the requirements of industrial applications,4,4'-?4,4'-isopropyl diphenoxy?bis?phthalic anhydride?BPADA)and4,4'-diaminodiphenyl ether?ODA?as the starting material for the amino group of linear polyimide?PI?.TDI,polycarbonate diol 1000?PCDL1000?,2,2'-dimethylol propionic acid?DMPA?,polyimide?PI?,N,N-two hydroxyethyl-2-amino hydroxyl ethyl propionate?HAHEP?as raw material for polyimide-modified waterborne hyperbranched polyurethane?WHBPU-PI?.Structure and properties of WHBPU-PI was characterized by FT-IR,stability analysis,thermogravimetric analysis?TGA?,differential scanning calorimetry?DSC?,water absorption,particle size analysis?PCS?,tensile strength analysis.The results show that the WHBPU-PI has good stability.With the introduction of PI,the heat resistance,mechanical properties and water resistance of WHBPU were significantly improved.Glass transition temperature increased by 10?or more.When the polyimide PI content of 7%,the weight loss of 50%of the temperature increased by 13?.This is beneficial to the industrial applications of WHBPU-PI.