Enhanced performance of biodegradable poly(butylene succinate)/graphene oxide nanocomposites via in situ polymerization

Highly reinforced and degradable lignocellulose biocomposites by polymerization of new polyester oligomers

Unbleached wood fibers and nanofibers are environmentally friendly bio-based candidates for material production, in particular, as reinforcements in polymer matrix biocomposites due to their low density and potential as carbon sink during the materials production phase. However, producing high reinforcement content biocomposites with degradable or chemically recyclable matrices is troublesome. Here, we address this issue with a new concept for facile and scalable in-situ polymerization of polyester matrices based on functionally balanced oligomers in pre-formed lignocellulosic networks. The idea enabled us to create high reinforcement biocomposites with well-dispersed mechanically undamaged fibers or nanocellulose. These degradable biocomposites have much higher mechanical properties than analogs in the literature. Reinforcement geometry (fibers at 30 µm or fibrils at 10–1000 nm diameter) influenced the polymerization and degradation of the polyester matrix. Overall, this work opens up new pathways toward environmentally benign materials in the context of a circular bioeconomy.

Cellulose biocomposites from nanocellulose or plant fibers with polymer matrix are often not degradable and suffer from insufficient mechanical properties to replace established materials. Here, the authors demonstrate the fabrication of hydrolytically degradable polymers through in-situ polymerization of new functionally balanced oligomers within high-content lignocellulose reinforcement networks.

Quantification of pre and post air plasma defected graphene oxide dispersed polymer blends for high dielectric applications

Polymer nano blends were more in demand for various domestic and industrial applications. In the present investigation, we modified the Polyvinylidene fluoride (PVDF)/Polysulfone (PSF) polymer blends by dispersion of pre...

Improvement of Barrier Properties of Biodegradable Polybutylene Succinate/Graphene Nanoplatelets Nanocomposites Prepared by Melt Process

Polybutylene Succinate (PBS)/Graphene nanoplatelets (GnP) nanocomposites over a range of GnP from 0 to 1.35 wt.%. were prepared by a melt process. A mixture of individual graphene nanosheets and aggregates was obtained by the addition of GnP in the PBS matrix. The presence of these fillers did not significantly modify the morphology, crystalline microstructure of the matrix or its thermal stability. However, a slight reinforcement effect of PBS was reported in the presence of GnP. The water sorption isotherm modelling with Guggenheim, Andersen and De Boer (GAB) equation and Zimm-Lundberg theory allowed a phenomenological analysis at the molecular scale. The presence of GnP did not modify the water sorption capacity of the PBS matrix. From a kinetic point of view, a decrease of the diffusion coefficient with the increasing GnP content was obtained and was attributed to a tortuosity effect. The influence of water activity was discussed over a range of 0.5 to 1 and 0 to 0.9 for water and dioxygen permeability. Improvement of the barrier properties by 38% and 35% for water and dioxygen permeability respectively were obtained.

Rapid Synthesis of Oxygen-Rich Covalent C2N (CNO) Nanosheets by Sacrifice of HKUST-1: Advanced Metal-Free Nanofillers for Polymers

A covalent oxygen-rich C₂N (CNO) network derived from metal-organic framework (HKUST-1) was innovatively synthesized by a rapid and green microwave irradiation method. This method can produce CNO multilayers efficiently, which paves a way for practical application of the nanosheets. Structural characterization and synthesis processes of CNO nanosheets were investigated to further understand the key role of HKUST-1. The as-prepared CNO has a layered feature, which theoretically favors to improve flame retardancy and mechanical performance of polymers. Desirable results were obtained as expected: the fire safety, antitensile, and impact resistance of polylactic acid (PLA) were prominently enhanced after adding CNO nanosheets, which can be attributed to the excellent dispersion and compatibility. PLA/CNO nanocomposite was self-distinguished at 2 wt % content of CNO, whereas the tensile strength was increased more than 36% compared with that of pure PLA, as well as the impact strength. This work broadens the application fields of CNO and endows it a possibility of actual application.

High-Performing Biodegradable Waterborne Polyester/Functionalized Graphene Oxide Nanocomposites as an Eco-Friendly Material

The development of high-performing nanocomposites of homogeneously dispersed graphene oxide in a waterborne polyester matrix with controlled interfacial interactions is a daunting challenge owing to the presence of strong cohesive energy in both. Thus, in this study, graphene oxide was functionalized with toluene diisocyanate and butane diol through a simple method and incorporated into the waterborne polyester matrix through a facile in situ bulk polymerization technique without using any compatibilizing agent or organic solvent for the first time. The thermoset of the nanocomposite was formed by curing it with hyperbranched epoxy of glycerol and poly(amido amine). The resultant thermosetting nanocomposites with 0.1-1 wt % functionalized graphene oxide exhibited significant enhancement in mechanical properties such as elongation at break (245-360%), tensile strength (7.8-39.4 MPa), scratch hardness (4 to >10 kg), toughness (17.18-86.35 MJ/m³), Young's modulus (243-358 MPa), impact resistance (8.3 to >9.3 kJ/m), and thermostability. Further, the Halpin-Tsai model was used to predict the alignment of graphene oxide. The nanocomposite was also biodegradable against the Pseudomonas aeruginosa bacterial strain. Furthermore, this nanocomposite exhibited strong catalytic activity for the aza-Michael addition reaction. Thus, the nanocomposite can be utilized as a high-performing sustainable material in different potential applications including as heterogeneous catalysts.

Interfacial modification of basalt fiber filling composites with graphene oxide and polydopamine for enhanced mechanical and tribological properties

Graphene oxide was grafted onto the surface of basalt fiber via polydopamine to enhance the interfacial adhesion of PA6 composites.

Unusual crystallization behavior of biodegradable poly(ethylene adipate) based nanocomposites induced by graphene oxide

GO increases both the nucleation density and the growth rate of PEA spherulites in nanocomposites.

Recent advances in the synthesis and applications of graphene–polymer nanocomposites

We summarize the recent advances in the modification of graphene with polymers and the synthesis and applications of high quality graphene–polymer nanocomposites.

Graphene-based materials: fabrication, characterization and application for the decontamination of wastewater and wastegas and hydrogen storage/generation

Graphene, as an ideal two-dimensional material and single-atom layer of graphite, has attracted exploding interests in multidisciplinary research because of its unique structure and exceptional physicochemical properties. Especially, graphene-based materials offer a wide range of potentialities for environmental remediation and energy applications. This review shows an extensive overview of the main principles and the recent synthetic technologies about designing and fabricating various innovative graphene-based materials. Furthermore, an extensive list of graphene-based sorbents and catalysts from vast literature has been compiled. The adsorptive and catalytic properties of graphene-based materials for the removal of various pollutants and hydrogen storage/production as available in the literature are presented. Tremendous adsorption capacity, excellent catalytic performance and abundant availability are the significant factors making these materials suitable alternatives for environmental pollutant control and energy-related system, especially in terms of the removal of pollutants in water, gas cleanup and purification, and hydrogen generation and storage. Meanwhile, a brief discussion is also included on the influence of graphene materials on the environment, and its toxicological effects. Lastly, some unsolved subjects together with major challenges in this germinating area of research are highlighted and discussed. Conclusively, the expanding of graphene-based materials in the field of adsorption and catalysis science represents a viable and powerful tool, resulting in the superior improvement of environmental pollution control and energy development.