Non‐isothermal crystallization of Ziegler Natta i‐PP‐graphene nanocomposite: DSC and new model prediction

Abstract

Crystallization occurs in processing i-PP-GnP nanocomposites, and these nanocomposites have the potential to replace traditional fillers and be used to fabricate advanced materials and technology. Therefore, this subject was comprehensively investigated by applying a recent crystallization model, non-isothermal DSC experiments, Raman spectroscopy, and WAXRD. The multi-layer GnPinduced nucleation and the crystal growth rates were modelled. The overall modelling effort generated new insights, results, and explanations. This study confirmed and elucidated, or refuted several published conclusions. It has also been reported that the present model can pursue differences in catalyst-mediated i-PP backbone defects (stereo and regio) by simulating the relative crystallization profile and determining the crystallization kinetic triplet (n, k o , and E a ). The multiple roles played by GnP were underscored, which exceed what the related literature currently reports. The Raman and XRD work revealed the interaction between GnP and i-PP. The shear-induced dispersion of GnP that occurs during extrusion significantly affected i-PP crystal size distribution. The present approach can also assess the effects of catalyst type and structure, and backbone defect types and their distribution on the non-isothermal crystallization of, in general, polyolefin blends and nanocomposites.

Non-Isothermal Crystallization Kinetics of Polyamide 6/Graphene Nanoplatelets Nanocomposites Obtained via In Situ Polymerization: Effect of Nanofiller Size

“…It was observed that the addition of GNPs did not significantly affect the X c values. The same behavior was also previously reported [54][55][56]. Theoretically, the addition of GNPs to PA6 can have two significant effects: heterogeneous nucleation, where GNPs provide sites for polymer molecules to form crystalline structures; and, physical hindrance, where GNPs can obstruct the movement of polymer molecules [57].…”

Surface modification of polyurethane nanocomposite films via nonsolvent‐induced phase separation accelerated by graphene nanoplatelets

“…Based on Figure 1A, it is evident that the addition of nonsolvent increased the intensity of the diffraction peak at 2θ = 20.5 , whereas the addition of graphene suppressed the diffraction peak. Despite the numerous reports of the positive effect of graphene on the crystallization of polymers due to their promising nucleating agent, [65][66][67][68] the addition of 5% of graphene nanoplatelets reduced the crystallinity of PU chains in the current study.…”

Polyolefin Catalyst Research: A Product‐Driven Industrial Perspective

“…Our several nonisothermal crystallization publications [117][118][119][120][121][122][123] list the advantages of nonoisothermal crystallization over isothermal one and the limitations of the existing non-mechanistic empirical models contributed by Ozawa, [124] Jeziorney, [125] and Liu et al [126] Such limitations include: -Assumption of first-order crystallization rate; -Inadequacy to (i) model a single cooling rate primary and secondary crystallization experiment, and (ii) predict crystallization mechanism, crystal growth dimension, and apparent activation energy of crystallization; -Incompetence to model the effects of variable cooling rates; -Double-logarithmic data analysis which is insensitive to parametric variables; and -Use of arbitrary data-fitting empirical parameters having no physical significance. We in details derived the following, preferably called nonisothermal Avrami-Erofeev crystallization model equation, that overcomes the aforementioned limitations: [117]…”

“…In practice, crystallizarion occurs nonisothermally in end product fabrication. Our several nonisothermal crystallization publications [117–123] list the advantages of nonoisothermal crystallization over isothermal one and the limitations of the existing non‐mechanistic empirical models contributed by Ozawa, [124] Jeziorney, [125] and Liu et al [126] . Such limitations include:…”