Study On The Synthesis And Modification Of Polyether Urethane

Polyurethane(PU) with high abrasion resistance, tear resistance and resistance to flexible is widely used in building materials, chemical products, light industry and so on,being a booming macromolecule material. The unique molecular structure of polysiloxane makes its unique performance which other materials do not have, such as high strength ultraviolet resistance, electrical insulation, acid and alkali corrosion resistance, hydrolysis resistance, resistance to ozone aging and physiological inertia etc. It widely attracts people’s attention and recognition in using polysiloxane modified polyurethane. This is a kind of effective method to improve the polyurethane weather ability. Mean while, it expands the application scope of polyurethane.In this paper, with the polypropylene glycol(PPG) as the soft segments and the IPDI,BDO as hard segments, polyether polyurethane resin with different ratio of raw materials were synthesized. Thermo-gravimetric curve proves that the percentage of hard and soft segments affects the thermal decomposition temperature of the material directly.The higher hard segments content is, the higher initial temperature of thermal decomposition is.With increasing of hard segments content, the polyurethane molecular weight gradually increases and viscosity increases simultaneously. When IPDI to PPG is 7:1 and 8:1,viscosity is moderate so liquidity is also suitable. The mechanical test results show that when the IPDI to PPG is 7:1 and 8:1, elongation at break of the material reaches 348.1%and 323.4%, the tensile strength reaches 13.2MPa and 16.5MPa respectively. All these show the optimal mechanical properties.With polydimethylsiloxane as modifying agent, different contents of organic silicone modified polyurethane were synthesized. IR, TGA, DSC and viscosity of the product have been characterized. Data prove that the glass transition temperature drops and initial pyrolysis temperature increases compared with the unmodified PU. When PDMS content reached 20%, tensile strength is 13.15 MPa, the elongation at break is 693.7%, which presents the optimal value. Accelerated aging experiments were carried out in the ozone,ultraviolet radiation, and ozone with ultraviolet respectively. The color and the yellow index tests show the embed organic silicon chain segment could improve the ability of resistance to yellowing of the polyurethane. Mechanical performance test proves that the organic silicon enhances polyurethane mechanical strength retention in extreme circumstances. From the images of the scanning electron microscopy(SEM) it can be seenthat the microstructure of modified polyurethane has little changed in extreme environment. From above, it is summarized that polyurethane endure-climate property has been greatly improved after organic silicon modified.