Influence of pre-shearing on the crystallisation of conventional and metallocene polyethylenes

Flow induced crystallization of LDPE nanocomposites: A rheological and morphological characterization

“…According to the literature [43][44][45][46][47][48], SALS technique can be successfully adopted to follow the melt crystallization and to appreciate both the characteristic temperatures of the process and the resultant morphology. The adopted experimental protocol is described in the experimental section and the applied flow conditions, carefully selected on the basis of preliminary melt crystallization experiments, are reported in Table 1.…”

“…To perform in-situ Rheo-SALS experiments, according to a well tested experimental procedures [43,44], the Linkam shearing device was mounted on a vertical bench equipped with a He-Ne laser light source ( = 635 nm) and two polarizers. As shown in Figure 9, according to the Hv configuration [47], these were set at 0 and 90°, respectively.…”

Influence of molecular composition on the development of microstructure from sheared polyethylene melts: Molecular and lamellar templating

“…The development of a comprehensive understanding of the crystallization behaviour of polydisperse polymer melts following the imposition of melt flow, represents a major challenge and, consequently, is a topic that has attracted considerable recent attention [1][2][3][4][5][6][7][8][9][10]. Whilst it is well appreciated that a degree of molecular variability is required to ensure processability and adequate final properties, the precise role of each molecular fraction in technologically relevant materials is not well understood.…”

Deep Quenching: A Special Method to Study Stress‐Induced Crystallization and Control the Lamellar Growth Direction

“…have been used to characterize the final crystalline microstructures. Furthermore, various in situ techniques, including rheooptical detection, [15][16][17][18][19][20] SAXS (small-angle X-ray scattering), [18,21,22] WAXD (wide-angle X-ray diffraction), [22] and SALS (small-angle light scattering), [23][24][25] have been applied to observe the flow-induced structures in the early stages of crystallization. Results from SAXS and rheooptical studies suggest that a stable scaffold (network) of nuclei, consisting of shear-induced microfibrillar structures along the flow direction superimposed by layered structures perpendicular to the flow direction, form in the polymer melt prior to the occurrence of primary crystallization.…”