Temperature‐induced changes in chain‐folded lamellar crystals of aliphatic polyamides. Investigation of nylons 2 6, 2 8, 2 10, and 2 12

摘要: Four members of the even-even nylon 2 Y series, for = 6, 8, 10, and 12, have been crystallized in form chain-folded lamellar single crystals from 1,4-butanediol studied by transmission electron microscopy (imaging diffraction), x-ray diffraction, thermal analysis. The structures these nylons are different those 6 many other nylons. At room temperature, two strong diffraction signals observed at spacings 0.42 0.39 nm, respectively; values differ 0.44 0.37 nm most ambient temperature. Detailed analyses patterns show that all triclinic unit cells. diamine alkane segments too short to sustain chain folds; thus, folds must be diacid cases. On heating temperature melt, transform into pseudohexagonal meet Brill transition which occurs significantly below melting point. similar cell elevated but its behavior on family is noticeably X 4 family, although only difference between families polyamides relative disposition amide groups within chains. results order understand structure, properties crystalline nylons, especially as a function detailed stereochemistry needs taken account.