A real‐time WAXS and SAXS study of the structural evolution of LLDPE bubble

Abstract

The structural evolution during the linear low-density polyethylene (LLDPE) film blowing has been studied with a combination of home-made blown film apparatus and in situ WAXS and SAXS measurements. Analyzing the evolution of orientation parameters and crystallinity of the bubble shows that the blown film process can be divided into four regions. Distinctly different features of LLDPE bubble are observed in first three regions: (a) lower orientation parameters during the blown film process, (b) higher crystallinity is required to form a deformable crystalline crosslinked network, and (c) the weaker stretching effect and the difficulty of reaching equilibrium when the crystal network deforms. These results should provide a basis for understanding the poor blown film stability of LLDPE.

Biodegradable Elastomer from 2,5-Furandicarboxylic Acid and ε-Caprolactone: Effect of Crystallization on Elasticity

“…In Figure S6, the in situ 2D WAXS patterns of PBFCL40 and PBFCL50 are presented, and a clear orientation of crystal structures was found. 46 The isotropic rings could be observed in these two samples at the strain of 0%. In region 1, the patterns of PBFCL40 and PBFCL50 changed from isotropic rings to arcs along the equator, indicating that the alignment of crystals already started at the early stage of stretching.…”

“…In Figure S6, the in situ 2D WAXS patterns of PBFCL40 and PBFCL50 are presented, and a clear orientation of crystal structures was found . The isotropic rings could be observed in these two samples at the strain of 0%.…”

Mesostructural study on graphenic-based carbon prepared from coconut shells by heat treatment and liquid exfoliation

“…Beyond XRD, here, WAXS measurement is performed to investigate the structure and phases of the obtained GC particles. WAXS is an x-ray technique typically employed to analyze the crystallinity in polymer systems [25,26]. Graphene has been surface-characterized using some material characterization techniques such as transmission electron microscopy (TEM) and atomic force microscopy (AFM) [17,27].…”

Synergistic and Competitive Effects of Temperature and Flow on Crystallization of Polyethylene during Film Blowing

“…Previous experimental results show that the evolution of crystallinity as a function of temperature before the frost line has a turning point during the film blowing, which corresponds to the formation of the crystalbased network, and the corresponding crystallinity is the intrinsic parameter of the molecular structure of the material. 35,36 Because the crystal diffraction ring of LPE significantly splits in the 2D WAXS patterns while the MPE does not, the relative crystallinity (χ′ c ) within a small angle along the equatorial direction is calculated to evaluate the content of crystals oriented in the take-up direction (the c-axis is parallel to the stretching direction) as shown in Figure 4c. Interestingly, the χ′ c of LPE and its bulk crystallinity are significantly different.…”