Syntihesis And Performance Study Of Polyurethane/Silicon Carbon Composite

Asphalt pavement is the main pavement structure of high grade highway in China and occupies very important status in our country. It has a serious structural failure after several years of service period, such as cracks, rut, water damage and so on. So, it is an important research direction to repair asphalt pavement fast and efficiently.In this study, polyurethane composites were prepared which is a new materials to repair asphalt pavement. The new materials not only have the characteristics of excellent mechanical properties but also have a good road surface adhesion. Besides, it's a new type of environment friendly materials without any organic solvent.Liquified MDI type polymers and TDI-80 type polymers were prepared by prepolymer method. The influence of liquified MDI type prepolymer/TDI-80 type prepolymer weight ratio and curing agent on mechanical property, glass transition temperature and thermal stability were investigated mainly in this paper. Results show that with the increase of liquified MDI type prepolymer/ TDI-80 type prepolymer weight ratio, the flow time and curing time decrease and the tensile strength, tearing strength and compression strength decrease first, and then increase. In order to make the system can folly incorporate the liquified MDI type prepolymer/TDI-80 type prepolymer weight ratio at 6/4 was appropriate. With the increase of the E-300/BDO/N204 weight ratio, the flow time and gelation time decrease, but the tensile strength, tearing strength and compression strength increase. In order to get good mechanical properties and suitable operation time, ultimately E-300/BDO/N204 weight ratio at 12/12/76 was suitable.To enhance the cohesive force between polyurethane and silicon carbide, the silicon carbide was modified with silane coupling agent KH550.The influence of KH550 content, drying temperature and reaction time on mechanical property, glass transition temperature and thermal stability were investigated in this paper. Results show that polyurethane/silicon carbide composite has the best mechanical performance when the KH550 content was 2%, the reaction time was 90 min, drying temperature is 70?.The materials were characterized by X-ray diffraction (XRD). It showed that silicon carbide crystal structure was changed. By using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), a improvement in the thermal stability was found after modification with KH550.By measuring the content of NCO at different times, study the reaction dynamics of the reaction of TDI-80 and N220. Calculate the rate constant of esterification reaction and branching reaction in different temperature through the secondary rate equation. Calculate the activation energy of esteriflcation reaction and branching reaction through the Arrhenius equation. It's showed that of esterification reaction and branching reaction were 27.7KJ/mol and32.6 KJ/mol, respectively.