Crystallization kinetics, structure, and rheological behavior of poly(ethylene terephthalate)/multilayer graphene oxide nanocomposites

Abstract

This work aims to produce poly(ethylene terephthalate)/multilayer graphene oxide (mGO) nanocomposites via continuous melt mixing in twin-screw extrusion, and to study the changes in crystallization and melt flow behavior. Three mGO contents (0.05, 0.1, and 0.3 wt%) were used. Differential scanning calorimetry analyses showed that at 0.1 wt%, mGO acted best as nucleating agent, increasing the crystallization kinetics as well as the melt crystallization temperature (T mc) by more than 20%. It was also observed that mGO increases the crystals perfection. The nucleating behavior was confirmed by X-ray diffraction and small angle X-ray scattering analyses, which showed a decrease in the composites' crystalline lamella thickness (l c) and long period. X-ray microtomography data confirms that this behavior is significantly affected by the mGO agglomerates distribution and specific surface area inside the polymer matrix. The rheological behavior was studied under two different conditions. It was noticed that under lower shear stresses the mGO particles hinder the polymer flow, increasing the composites viscosity and the pseudo-solid character. However, under higher shear stresses, for example, when flowing through a die, the nanomaterial enters its "superlubricity state," acting as a lubricant to the flow. This is industrially interesting, because it may allow the use of less severe processing parameters to produce the nanocomposites.

Interface adjustment between poly(ethylene terephthalate) and graphene oxide in order to enhance mechanical and thermal properties of nanocomposites

“…Similar results were obtained by Pinto et al [ 31 ] When evaluating PET/GO nanocomposites (0.05%, 0.1%, and 0.3% by weight), they observed higher kinetics and crystallization melting temperature at 0.1% by weight of the nanomaterial.…”

“…[ 26–28 ] With the need for increasingly resistant and functional materials, interest in obtaining polymer nanocomposites is growing, as the characteristics of the matrix and nanomaterials are combined, which makes it possible to obtain a new material with improved properties. [ 29,30 ] PET nanocomposites reinforced with graphene‐based materials have shown good performance, with improvements in degree of crystallinity, [ 31 ] gas barrier and mechanical properties. [ 32 ] PET nanocomposites based on graphene nanosheets with different contents synthesized by Shabafrooz et al [ 33 ] presented an increase in the elastic modulus, however with a reduction in elongation and toughness.…”

Application of sustainable treatments to fiber surface for performance improvement of elastomeric polyurethane reinforced with basalt fiber

“…The strong adhesion between phases thanks to the silane and epoxy layer on the BF surface resulted in the flowing of fibers forward with a higher flow rate. [ 77–80 ]…”

From two‐dimensional materials to polymer nanocomposites with emerging multifunctional applications: A critical review

“…In addition to gains in the properties mentioned throughout this manuscript, other enhancements have already been reported, for example, photoprotection, modification of surface energy, which can lead to some degree of biocompatibility, gas barrier, and processing aid due to superlubricity effects. [ 172,282–286 ]…”