Shear-induced crystallization of polyamide 11

Abstract Shear-induced formation of crystal nuclei in polyamide 11 (PA 11) was studied using a conventional parallel-plate rheometer. Crystallization PA after shearing the melt at different rates for 60 s followed by evolution complex viscosity. The sheared samples showed an optical microscope gradient structure along radius, due to increasing shear rate from center edge. critical shear-induced identified position where distinct change semicrystalline superstructure is observed, being around 1 2 −1 . Below this threshold, space-filled spherulitic developed as quiescent-melt crystallization. Above value, between and 5 , increased number point-like detected, connected with randomly oriented crystals. Shearing even higher led further increase growth crystals such that chain axis parallel direction flow. In addition, microscopy confirmed long fibrillar structures condition. specific work flow calculated allow comparison 66 66). This case more needed than 66, discussed terms chemical repeat unit chains. Graphical abstract