WANG Miao, PAN Hongye, LIU Xuesong, WANG Longhu*
In this paper, two polymorphs of glycolide(form α, form β) were prepared. The crystal structures of two polymorphs of glycolide were all characterized by differential scanning calorimetry(DSC), infrared spectroscopy(IR), powder X-ray diffraction(PXRD) and single crystal X-ray diffraction(SCXRD). The results indicate that form α is in the orthorhombic system, space group Pbca, with unit cell parameters: a=5.245 1(6) Å, b=7.450 7(11)Å, c=11.793 4(13) Å, V=460.88(10)Å3, Z=4, while form β is in the monoclinic system, space group P121/n1, with unit cell parameters: a=6.718 1(10)Å, b=14.987 5(18)Å, c=9.647 8(17)Å, β=98.958(15)°, V=959.6(2)Å3, Z=8. Form α of glycolide are significantly different from form β in stability and moisture absorption, and the difference may influence the reactions and product quality in order to obtain polyglycolic acid.