粉末X射线衍射法对酰胺酸-酰亚胺共聚物晶体结构的研究

The Study on the Crystalline Structure in Copolyamic Acid-Imide by X-Powder Ray Diffractometer

通过粉末X射线衍射仪对不同工艺条件获得的PMDA-ODA型酰胺酸-酰亚胺共聚物(PA-I)粉末的XRD图谱进行分析表明,PA-I粉末为半晶粉末,使用消除无定型鼓包的XRD图谱指标化,计算出晶体结构为三斜晶系,空间群为P1。采用Pawley全谱精修晶体结构,结果表明,随着酰亚胺化时间的延长和酰亚胺化温度的提高,PMDA-ODA的晶胞参数、微晶尺寸和晶格畸变都呈现规律性变化。

Copolyamic acid-imide （PA-I） powders with different imidization degree were prepared in solution by thermal imidization of polyamic acid （PAA） synthesized from pyromellitic dianhydride （PMDA） and 4,4＇-oxydianiline （ODA） on different reaction conditions. X-ray diffraction （XRD） results of these powders indicated that they are semi-crystalline. After all of amorphous PA-I bumps in XRD patterns were deducted, reflections of crystalline PA-I were used to index and calculate crystalline structure. The structure is triclinic and space group is P1. It is concluded that unit cell parameters, crystallite size and microstrain of PA-I powders change regularly as imidization time prolonged or imidization temperature rose by Pawley refinement of XRD patterns of crystalline portion.