Study On The Synthesis And Surface Modification Of Polyurethane

In order to study the structure and properties of polycarbonate-polyurethane (PCU), it was synthesized by two different methods and followed by surface modification. Characterizations were performed in various ways.First, PCU was synthesized using polycarbonate diol (PCD), 1, 4-butanediol (BD), and 4, 4'-methylene diphenyl diisocyanate (MDI) as starting materials and by the melting one-shot method and the solution pre-copolymerization method, respectively. The synthesized PCU was then characterized by infrared spectroscopy (IR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), small-angle X-ray scattering (SAXS), and tensile strength measurement. The IR showed that the polymer synthesized by the above two methods both have the polycarbonate-urethane structure and the tensile measurement showed good mechanical performance of the polymer. The DSC and TGA data showed that there is an obvious soft-hard glass transition area, which indicated the existence of the micro-phase separation structure. The extent of the phase separation was affected by the ratio of starting materials, the molecular weight of PCD, and the polymerization method. The decomposition upon heating was observed in two steps. SAXS result showed that the radius (r₂), the distance between domains (d₂), and gyral radius (R₂) of hard segment micro-domain were fairly affected by the starting materials ratio and soft segment content. However, the radius (r₁) and the distance (d₁) of the soft segment micro-domain were strongly affected by above factors, that is, r₁ and d₁ increased as the content of the soft segment increased.Chloroactic polyethylene monoester (CPEG) was synthesized using polyethylene glycol (PEG) and chloroacetyl chloride (CAC) and reacted in tetrahydrofuran (THF). Effects of the starting materials composition and the concentration of the solution on the product were investigated. The reaction of CPEG with excessive dimethylamine solution yielded N, N-dimethyl glycine polyethylene glycol monoester (APEG). IR and ¹H-NMR showed predicted structures of CPEG and APEG. In order to increase the number of grafting points, multi-amido polymers (aminoehylaminopropyl poly(dimethyl siloxane) and polyacylamide) were first introduced to surface of PCU film, then grafted with APEG, finally, an ring-opening reaction of propane sultone on the PCPU surface was performed. The single hydroxyl PEG with sulfoammonium...