Preparation and Performance Comparison Study of Polyurethane Underrail Pad
In order to optimize the production process of polyurethane underrail pad,polyurethane underrail pad were prepared by a high-pressure and low-pressure mixed molding process.Mechanical properties,infrared spectroscopy analysis,dynamic mechanical analysis,thermogravimetric analysis,and scanning electron microscopy testing were carried out,and compared with commercially available products.The results show that the performance of the two types of prepared polyurethane underrail pad meet the relevant standard requirements,are comparable to the performance of products on the market and had better low-temperature performance.Compared to the low-pressure mixing molding process,the foam hole diameter of the underrail pad prepared by the high-pressure mixing molding process is smaller(50 μm),with more uniform distribution,better mechanical properties,and lower compression permanent deformation and dynamic static stiffness ratio of 3.8%and 1.29,respectively.The residual carbon content of polyurethane materials with the same formula after thermal weight loss is the same,but there are differences in the decomposition temperature and glass transition temperature at different stages.The elastic and damping properties of the underrail pad made from it are also different at the operating temperature.It is recommended to use high-pressure mixing molding technology to prepare polyurethane underrail pad.
heavy haul railwayshigh pressure mixing molding processexperimental researchunderrail padpolyurethane foamfastener system
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