Synthesis And Charaterization Of AB Type(HO--NCO)isocyanate Protected By Dimethylsilyl Group

As a new of unique polymers,polyurethane has been widely used in our daily life due to its favourable and controllable propertiesinterest.They are extensively used in foams,coatings,elastomer,insulation materils and adhesives.With the development of industrialization,people had put forward more requirements on the properties of the polyurethane material.In this thesis,we firstly describe the development of polyurethane and the main factors affecting the polymerization of polymerization.Base on the theories of molecular weight distribution and research of our lab,we have designed a route for the synthesis of dimethyl alkyl silicon protection AB type(HO--NCO)isocyanate monomer.It could be another way for the research controlled molecular weight distribution.The main contents include the following aspects:(1)Preparation of dimethyl alkyl silicon protection AB type(HO--NCO)isocyanate monomer.Due to the active structure of HO--NCO,it need protective agent to protect hydroxy when we use HO--NH₂ as raw material to preparing AB type(HO--NCO)isocyanate monomer,then used solid phosgene to preparing isocyanate group.Finally,we have prepared five AB type(HO--NCO)isocyanate monomer which had protected by silicone agent.(2)Discovered a new method for the synthesis of symmetrically substituted urea.We have synthesized substituted urea through the corresponding isocyanate and trimethylsilyl alcohol with a high yield.The method is simple,mild experimental conditions,metal-free catalyst and a wide range of advantages.It is important for synthesis of substituted urea compounds.(3)We use fluorescence emission spectroscopy and UV-Vis absorption spectroscopy to detecting the novel urea derivative TBSU and MDSU.We have done some research,including:selective detection of ions,competitive assay of ions,concentration gradients,complex-ratio,stability constant,reversible fluorescence,response time and limit of detection.Base on the infrared spectrum of complex to determine the corresponding complex mechanism.The results show that TBSU and MDSU response quickly to Fe³⁺/F^–and Fe³⁺respectively and reflecting the good performance of the fluorescence sensor.