塑料 乙酸纤维素 利用热的不同循环在生产模制样品中光吸收量的测定

[中文适用范围]： 该方法适用于乙酸收率为54％～2.5％的乙酸纤维素。 本标准也可适用于其他颜色不强烈且可在规定条件下成型的透明塑料。 两次吸收测量，一次在可见光谱的红端，一次在蓝端，足以表征材料对光的吸收。 描述了材料的制备、增塑剂掺入的两种方法以及测试样品的模具成型。 为了确定初始光密度，使用给予最小可行加热量的样品。 计算 25 mm 厚度处的光密度作为初始光吸收率。 进一步加热后的光吸收是通过对在模制过程中使用较长时间加热制备的样品进行类似测量来获得的。 [外文原描述]： This method is intended for cellulose acetate having an acetic acid yield of 54 % ± 2.5 %. It may also be applicable to other transparent plastics which are not strongly coloured and which can be moulded under the specified conditions. Two measurements of absorption, one at the red end and one at the blue end of the visible spectrum, are sufficient to characterize the absorption of light by the material. Describes the preparation of the material, two methods for the incorporation of plasticizers and die moulding of the test specimen. For the determination of the initial optical density, specimens given the smallest practicable amount of heating are used. The optical density at 25 mm thickness is calculated as the initial light absorption. The light absorption after further heating is obtained by similar measurements on specimens prepared using a longer period of heating during moulding.