喷涂聚脲与聚氨酯防护涂层的自然环境老化性能研究

Study on Natural Aging Properties of Sprayed Polyurea and PU Protective Coatings

采用海洋大气环境户外自然曝晒的方法,研究了喷涂聚脲涂层(QF-162涂层)和喷涂聚氨酯涂层(QF-178涂层)的力学性能、分子内部结构的变化。结果表明:经过自然曝晒2 493 d后,QF-162涂层颜色变化明显,失光率为86.84%,拉伸强度下降29.37%,断裂伸长率下降14.38%;QF-178涂层颜色变化十分显著,失光率达89.63%,拉伸强度下降90.71%,断裂伸长率下降98.75%。FT-IR微观测试结果表明:在经过2 493 d的户外自然曝晒后,QF-162涂层只有涂层表面分子的化学键出现了断键,分子内部结构变化不大;而QF-178涂层分子内部结构发生显著的变化,分子的化学键几乎全部断裂,涂层完全失去了使用价值。

The mechanical properties and molecular structure of sprayed polyurea coating （QF-162 coating） and sprayed polyurethane coating （QF-178 coating） were studied by out- door natural exposure in marine atmosphere. The results showed that the color change of QF- 162 coating after outdoor exposure for 2 493 d was obvious, the tensile strength decreased by 29. 37% and the elongation at break decreased by 14. 38%. The color change of QF- 178 coat- ing was very significant. The tensile strength decreased by 90. 71% and the elongation at break decreased by 98.75%. The results of FT-IR test showed that only the chemical bond of coating molecules on the coating surface was broken after natural exposure of QF-162 coating and the internal structure of the coating did not change much. However QF-178 coating after outdoor exposure for 2 493 d, the internal structure of molecular was changed significantly. Al- most all the chemical bonds of molecules were broken and the use value of the coating was completely lost.