<正> 红外辐射对物质有热效应,但并不是所有波长的红外辐射对每一样品都有相同的热效应。由于各样品的分子结构不同,对各种波长有选择性吸收的特性。当一定频率的红外线辐射到样品时,就被样品分子中相同振动频率的键吸收,这种选择性吸收称特征吸收。吸收的结果,依样品分子的振动、转动加剧,振幅加大(频率不变),分子间的摩擦加剧,从而使分子振动动能、转动动能转变成分子的平动动能,使样品的温度升高,加速溶剂分子的蒸发、挥发或加速涂料的缩合、聚化、固化,达到涂层的干燥。本试验就是根据红外干燥的这一机理测试各涂料的最佳干燥波长。 某一键的伸缩振动频率可根据公式计算。由于绝大多数具有非对称性分子结构的物质(如水、有机物、油漆、树脂等)的化学键振动的基频均出现在中红外区域,因此,我们选择中红外区域(λ=2.5-25μm或ν=4000-400cm~(-1))作红外吸收光谱测试。

Using 2.5-25μm infrared rays, tests by Infrared Absorption Spectrum have been made on different lacqure coatings of surfaces of furniture, boards of sewingmach-ines, etc. coated with polyurethane clear lacquer. According to the theory of molecular structure and the absorbent property of different lacquer coatings the best infrared wave-length of dried coatings has been obtained. This will provide a reliable basis for the choosing of infrared radiation source in production.