Synthesis And Properties Study Of Polysulfide-based Polyurethane

Polysulfide is a polymer containing S atomic, it is widely used in various areas because of its excellent properties. It was mainly used in sealants, but its mechanics performance defect limits its wide application. This paper studied the modification on the traditional polysulfide with thiol sealing end and polysulfide with epoxy sealing end, as well as synthesis and thermal properties of polysulfide-based polyurethane with the polysulfide. The research focused on the open loop modification of epoxy polysulfide and polyurethane prepolymerization system for getting different types of polysulfide-based polyurethane. Then we investigated the structure and performance of polysulfide-based polyurethane. The novel points of the article contain three aspects in the following:(1) With thiol sealing end polysulfide, poly tetrahydrofuran ether (PTMG), diphenyl methane diisocyanate (MDI) as raw materials, to prepare polysulfide-based polyurethane composite material. The structure, thermal mechanical properties and degradation activation energy of polysulfide-based polyurethane were characterized by FT-IR, DSC and TGA. Polyurethane modified with G4and G21C polysulfide with improved degradation activation energy up to171.36KJ/mol had better thermal stability compared to unmodified polyurethane.(2) With the ring-opening reaction of the epoxy polysulfide and3-amino propyl triethoxysilane (APTES), to synthesize the modified polysulfide. Study on its curing and thermodynamic performance.(3) With the ring-opening reaction of epoxy polysulfide modified with different amines to prepare different types of modified polysulfide. Using PTMG, MDI as raw materials to synthesize polyurethane prepolymers terminated with isocyanate root. Then we prepared polysulfide-bases polyurethane composite material through with the crosslinking reaction between polyurethane prepolymers and modified polysulfide. The structure and properties of polysulfide-based polyurethane were characterized by FT-IR, DSC, TGA and SEM. The PU-BA and PU-DETA of Polysulfide-bases polyurethane have good thermal stability, the5%weight loss temperature is295℃and287℃respectively. The thermal stability of polysulfide-bases polyurethane, with the addition of the APTES, was preferable. DMA showed that polysulfide-based polyurethane has good low-temperature performance.