Density of Amorphous Polyethylene Terephthalate
Density of Amorphous Polyethylene Terephthalate
复制标题
非晶态聚对苯二甲酸乙二醇酯的密度
作者：
A. B. Thompson;D. Woods
聚对苯二甲酸乙二酯可以熔纺，然后热拉伸形成连续长丝纱1，以“涤纶”的商品名销售。在淬火或旋转形式中，它具有非常低的分子取向度，X射线图显示出特征性的无定形晕，没有结晶反射的证据。该无定形形式的密度为1.335克/升。c.c.，而计算的微晶晶胞密度为1.455 μ m/cm。c.c.2.随着结晶度的开始，由密度的增加、X射线图中的微晶反射的生长和样品的脆性的增加指示，X射线图中的无定形晕消失，因此不可能用X射线估计结晶度。然而，它可以从898 cm-1和875 cm-1波段的红外吸收比3和密度估算出来。
POLYETHYLENE terephthalate can be melt-spun and afterwards hot-drawn to form continuous filament yarn1 marketed under the trade name of ‘Terylene’. In the quenched or spun form, it possesses a very low degree of molecular orientation, and the X-ray diagram shows a characteristic amorphous halo with no evidence of crystalline reflexions. The density of this amorphous form is 1.335 gm./c.c., whereas the calculated crystallite unit-cell density is 1.455 gm./c.c.2. With the onset of crystallinity, indicated by an increase in density, the growth of crystallite reflexions in the X-ray diagram, and an increase in the brittleness of the sample, the amorphous halo in the X-ray diagram disappears and hence no X-ray estimate of the degree of crystallinity is possible. It can, however, be estimated from the ratio of the infra-red absorptions in the 898 cm.−1 and the 875 cm.−1 bands3, and from the density.