Dependence of the Brill Transition on the Crystal Size of Nylon 10 10

Nylon 10 10 crystals, which isothermally crystallized from the molten state and cold crystallized from melt-quenched samples at various temperatures, were investigated by using temperature-variable wide angle X-ray diffraction (WAXD) and small angle X-ray scattering (SAXS). No Brill transition occurred for the melt-crystallized crystals. However, this transition was easily observed for the cold-crystallized nylon 10 10, and the transition temperature is pertinent to the crystallization temperature. The sizes of these crystals was determined by SAXS and correlated with the Brill transition temperatures ( T B ). It was found that the T B had a linear relationship with the size of crystals, which was used to predict the T B for those crystals with thick lamella and to calculate the crystal size showing T B below room temperature. Nylon 10 10 crystal will possess the γ form (pseudohexagonal form) rather than the α phase at room temperature if its size becomes small enough.