Amelia Linares

Bionanocomposites based on poly(trimethylene 2,5‐furandicarboxylate)‐block‐poly(tetramethylene oxide) (PTF‐b‐F‐PTMO) with various contents of carbon nanofibers, graphene nanoplatelets and a hybrid system of these nanoparticles are synthesized via in situ polymerization. The dispersion of nanoparticles in the nanocomposites is determined using a scanning electron microscope and optical microscopy images. The thermal properties are studied employing differential scanning calorimetry, dynamic mechanical thermal analysis, and thermogravimetric analysis. The melt viscosity of the synthesized materials is determined using rheological measurements. Mechanical properties, along with the thermal and electrical conductivity, are also analyzed. The synthesized polymer nanocomposites are processed using injection molding and they display mechanical properties of elastomers during mechanical testing, which indicates that the obtained materials are, in fact, thermoplastic elastomers (TPE). Compared to a neat matrix (PTF‐b‐F‐PTMO 50/50), the incorporation of nanoparticles causes an increase in the value of the degree of crystallinity and the value of the tensile modulus values (E) of the nanocomposites. Such reinforced bionanocomposites are especially interesting from an applicative point of view. They can be used as components of fuel systems, bumpers, or cupholders.

In this article, the effect of the addition of graphene oxide (GO) and reduced graphene oxide (rGO) on the mechanical properties, thermal stability, and electrical conductivity of polyvinyl alcohol (PVA) has been investigated. Different weight percentages of nanofillers ranging from 0.5 to 5 wt% have been combined with PVA. The ultrasonic technique has been applied to disperse nanofillers in the PVA solution. The nanocomposite films have been prepared via solution casting technique and the dispersion of nanofillers into the PVA has been studied through optical microscopy. The microstructure, crystallization behavior, and interfacial interaction were characterized through X‐ray diffraction and Fourier transform infrared spectroscopy. Differential scanning calorimetry (DSC) and thermogravimetric analysis have been applied to study the thermal properties of the prepared nanocomposites. The DSC results revealed that the crystallization temperature and melting temperature were enhanced in the presence of GO nanofiller. Besides, the tensile strength at break was improved along with the addition of GO; however, elongation at break for PVA/GO and PVA/rGO was diminished. Moreover, all specimens showed insulating behavior and the only sample was electrically conducting, which contain a high amount of rGO (5 wt%).

This work reports a study on the influence of graphene oxide (GO) and reduced graphene oxide (rGO) on the functional properties of poly(trimethylene terephthalate)-block-poly(caprolactone) (PTT-block-PCL-T) (75/25 wt.%/wt.%) copolymer, obtained from dimethyl terephthalate (DMT), 1,3-biopropanediol and polycaprolactone diol (PCL) via in situ polymerization. The article presents, if and how the reduction of graphene oxide, in comparison to the non-reduced one, can affect morphological, thermal, electrical and mechanical properties. SEM examination confirms/reveals the homogeneous distribution of GO/rGO nanoplatelets in the PTT-block-PCL-T copolymer matrix. More than threefold increase in the value of the tensile modulus is achieved by the addition of 1.0 wt.% of GO and rGO. Moreover, the thermal conductivity and thermal stability of the GO and rGO-based nanocomposites are also improved. The differential scanning calorimetry (DSC) measurement indicates that the incorporation of GO and rGO has a remarkable impact on the crystallinity of the nanocomposites (an increase of crystallization temperature up to 58 °C for nanocomposite containing 1.0 wt.% of GO is observed). Therefore, the high performances of the PTT-block-PCL-T-based nanocomposites are mainly attributed to the uniform dispersion of nanoplatelets in the polymer matrix and strong interfacial interactions between components.

Broadband dielectric spectroscopy has been used to characterize in deep the relaxation behavior of novel bio-based aliphatic-aromatic block copolymers based on poly(butylene terephthalate)...

The chemical structure–dynamics relationship for poly(trimethylene 2,5-furanoate) and poly(trimethylene 1,4-cyclohexanedicarboxylate) was investigated via dielectric spectroscopy and compared with that of poly(trimethylene terephthalate) in order to evaluate the impact on the subglass dynamics of the chemical nature of the ring. Further comparison was accomplished with the neopentyl glycol containing counterparts: poly(neopentyl 2,5-furanoate) and poly(neopentyl 1,4-cyclohexanedicarboxylate). Our study reveals a multimodal nature of the subglass β process. For the more flexible polymers (containing cyclohexane rings) three modes for the β process were detected. The faster mode was assigned to the relaxation of the oxygen linked to the aliphatic carbon, the slower one to the link between the aliphatic ring and the ester group, and the third mode to the aliphatic ring. For stiffer polymers (containing aromatic rings), the local modes appear more coupled. This effect is more evident in the polymers with the furan ring where essentially a single β mode can be resolved.

Poly(trimethylene terephthalate) (PTT) composites filled with well‐dispersed functionalized multi‐walled carbon nanotubes (MWCNT‐COOH) and graphene nanosheets (GNS) were prepared through in situ polymerization. The effect of increased nanotubes and nanosheets concentration on the electrical conductivity and rheological behavior was investigated. The electrical conductivity increased by about ten orders of magnitude for PTT/MWCNT‐COOH/GNS composites with 0.4 wt% of MWCNT‐COOH and 0.3 wt% of GNS content. For insulating hybrid polymer nanocomposites, with a MWCNT‐COOH content ≤ 0.2 wt%, GNS produces a synergic effect by acting as junction additive for MWCNT leading to additional conductive pathways. However, for hybrid nanocomposites with 0.4 wt% of MWCNT‐COOH further addition of GNS caused only slight improvement in electrical conductivity. Additionally, rheological analysis confirmed interconnected or network‐like structures formed as a result of nanofiller‐nanofiller and nanofiller‐polymer interactions. POLYM. COMPOS., 39:2961–2968, 2018. © 2017 Society of Plastics Engineers