Crystallization kinetics and nanomechanical behavior of biobased poly(ethylene 2,5‐furandicarboxylate) reinforced with carbon nanotubes

Abstract

Poly(ethylene 2,5‐furandicarboxylate) (PEF) is one of the most widely known biobased polyesters due to its outstanding gas barrier and mechanical properties, making it the number one candidate to substitute poly(ethylene terephthalate) (PET). However, its crystallization from the melt is much slower compared to PET, affecting the overall processing of the material. For this reason, PEF nanocomposites containing various carbon nanotubes (CNTs) loadings (0–2.5 wt%) have been in situ synthesized in this work. Differential scanning calorimetry (DSC) measurements were conducted to evaluate all the prepared materials' isothermal and nonisothermal crystallization kinetics. Isothermal kinetics using the Avrami and Hoffman–Lauritzen (H–L) theories suggested that the nucleating effect of the CNTs is more profound during the crystallization from the melt, where the higher crystallization rate is observed in the case of PEF/2.5 CNTs nanocomposite. This is also confirmed by the nonisothermal crystallization analysis. The nucleation activity of the filler was estimated by Dobreva's method, which revealed that higher CNTs (1 and 2.5 wt%) content presents increased nucleation efficiency during the process. The nanoindentation results showed that the addition of CNTs in the PEF matrix enhanced the nanomechanical properties of PEF. Semicrystalline samples presented significantly higher hardness (H) and elastic modulus (E) values compared to their amorphous counterparts, where semicrystalline PEF/2.5 CNTs nanocomposite presented 135% increase of E compared to the amorphous neat PEF.

Incorporating Graphene Nanoplatelets and Carbon Nanotubes in Biobased Poly(ethylene 2,5-furandicarboxylate): Fillers’ Effect on the Matrix’s Structure and Lifetime

“…PEF’s crystal density has been reported to be 1.548 ± 008 g/cm 3 , while the amorphous one is equal to 1.434 ± 003 g/cm 3 [ 30 ]. The thermal and mechanical properties of the prepared materials in this study have been reported in previous publications [ 28 , 29 ]. PEF/GNPs, PEF/CNTs, and hybrid PEF/GNPs/CNTs nanocomposites have been prepared in this work by the two-stage transesterification/polycondensation method in a glass batch reactor as described in our previous work [ 27 ].…”

“…PEF/CNTs present slightly higher crystalline fraction values than the PEF/GNPs counterparts, with the exception of 2.5 wt.% filler content, which presents the same value. Increased crystallinity in polymers results in improved mechanical properties; in our previous works, the crystalline PEF/GNPs and PEF/CNTs nanocomposites presented significantly higher hardness and elastic modulus values when compared to their amorphous counterpart and neat PEF [ 28 , 29 ]. This behavior is attributed to the highly ordered lamellae which are characterized by a more significant intermolecular bonding leading to an enhanced hardness, strength, and elastic modulus.…”

“…To this end, PEF nanocomposites containing GNPs, CNTs, and hybrids comprising both fillers were in situ synthesized. Previous studies of the prepared PEF/GNPs and PEF/CNTs nanocomposites indicated the high nucleation efficiency of both fillers and their reinforcing effect on the matrix’s nanomechanical properties [ 27 , 28 , 29 ]. Therefore, to obtain a more complete picture of each filler’s effect on the physical properties of PEF, the matrix’s crystallographic parameters, the effect of the ultrasonication process on each filler state, and the polymer’s lifetime when GNPs, CNTs, and both fillers are incorporated into the biobased polyester were examined in this work.…”

Rheological percolation, gel‐like behavior and electrical conductivity of multi‐walled carbon nanotubes filled ethylene‐vinyl acetate copolymer/acrylonitrile‐butadiene rubber nanocomposites

“…Single‐walled (SWCNTs) and multi‐walled carbon nanotubes (MWCNTs) are now extensively incorporated into the polymer matrices in order to obtain the materials with higher mechanical, thermal, and electrical properties 1–6 . These properties are mainly associated with the formation of the nanofillers network within the polymer.…”

“…Single-walled (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) are now extensively incorporated into the polymer matrices in order to obtain the materials with higher mechanical, thermal, and electrical properties. [1][2][3][4][5][6] These properties are mainly associated with the formation of the nanofillers network within the polymer. However, when a nanocomposite is in the molten state, the structure of the nanofillers network can be altered because of the nanofillers diffusion and aggregation due to the thermodynamic instability.…”