Stretchable strain sensors with high sensitivity and good stability are crucial for wearable healthcare devices and tactile sensors for robots. Herein we present a new technique to synergistically ...improve sensors' sensitivity and cyclic stability by hybridising carbon nanofibers (CNFs) with graphene nanoplates (GNPs) within polydimethylsiloxane (PDMS) medium. The results reveal that, compared with equivalent sensors containing only CNFs or GNPs, the hybridised sensors show significantly better performance with a greater linear range up to ∼50% of strain and much-improved stability (less drift) under repeated loading, which is quantitatively reflected by the synergy ratio of linear range and drift rate. Increasing the concentration of hybrid carbon fillers can further increase sensors sensitivity. Therefore, the hybridisation of 1D and 2D nano-carbon materials offers a new route for increasing the sensitivity and cyclic stability of flexible strain sensors.
The microphase separation behavior of polyurethane (PU) strongly affects its mechanical, thermal, electrical, and other functional properties. Adding fillers to change the degree of microphase ...separation (DPS) in PU is a convenient and efficient method. Although many scholars have tried to regulate the microphase separation of PU by adding fillers, there are still many controversies about the effect. In this review, we classify commonly used fillers into three categories according to their morphology: spherical fillers, fibrous fillers, and layered fillers, and summarize their effects on the microphase separation behavior of PU. We explore the similarities and differences in the mechanisms by which different fillers affect the microphase separation of PU, and find that the polarity, morphology, size of fillers, and preparation method have a significant impact on the degree of microphase separation in PU. The impact of microphase separation on the mechanical properties of PU has also been summarized to illustrate their close relationship. We hope that these summaries will provide some guidance for the development of new high‐strength and multifunctional PU composites.
Highlights
Summarized recent research progress on effect of common fillers on DPS of PU.
Common fillers are classified into three categories based on their morphology.
Common laws of the fillers impact on the DPS are classified and discussed.
The close relationship between DPS and mechanical properties is reviewed.
Provided information for high‐strength and multifunctional PU development.
Three categories are classified for commonly used fillers based on their morphology, and the similarities and differences in the mechanisms by which microphase separation of polyurethane is affected by different fillers are explored.
Hybrid fillers of different geometries are increasingly utilized for the development of functional polymer composites. We herein report the role of HDPE-g-MAH as a compatibilizer for ternary ...composites consisting of HDPE, multi-walled carbon nanotubes and hexagonal boron nitride (BN). Through melt blending, HDPE-g-MAH can reduce the agglomeration of fillers and facilitate the formation of network structure. Due to the synergistic effect, ternary composites have demonstrated significantly higher thermal conductivity than those binary composites, and their maximum increase relative to the matrix is 262%. The mechanical performance and thermal conductivity are explained from perspectives of the morphology and crystallinity of the composites. The rheological properties of both binary and ternary composites have close relationship with their thermal conductivity. Although a high fraction of BN nanosheets can greatly reduce the electrical conductivity of ternary composites, they posed little effect on the electromagnetic interference shielding performance, owing to their electrical insulating nature. This research can provide new clues for the development of functional materials.
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Improving thermal stability of the ceramic-polymer based nano-composited electrostatic capacitors is the key element to their practical applications in harsh environment. In this paper, Fe3O4 @BaTiO3 ...particles with thermal conductive core and high-k shell were prepared and used as fillers to improve the thermal stability and high temperature energy storage density of poly-(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) based composited films. Compared to the pure polymer, the films with 10 wt% fillers showed enhanced temperature stability at the range of 40–120 °C. The high-temperature (120 °C) average breakdown strength reached at 1615 kV/cm with ~170% higher than the pure P(VDF-HFP) (970 kV/cm). The discharged energy storage density (120 °C) was 1.68 J/cm3 (1750 kV/cm), which was enhanced up to 1150% comparing to that of pure P(VDF-HFP) (0.146 J/cm3 at 1300 kV/cm). The increased thermal conductivity and the Internal Barrier Layer Capacitor (IBLC) effects at the conductive-insulating interfaces contribute to the enhanced features. The results in the present work explored an effective way to prepare high temperature dielectric nanocomposites for harsh applications in energy storage field.
The interest in sustainable materials and technologies has increased significantly due to environmental issues triggered by using plastics and their associated wastes. Every year more than ...400 million metric tons (Mt) of plastic production takes place globally, out of which 350 Mt plastic convert into plastic waste. Plastic waste mostly consists of polyolefin and their contribution to plastic waste is approximately 50%. Therefore, this review is focused on upcycling polyolefin waste by manufacturing natural/sustainable filler-based biocomposites. This is the novelty of the present review as a detailed review of the manufacturing of polyolefin waste-based biocomposites and their 3D printing suitability is not available in the literature. Natural filler-based biocomposites reduce the use of synthetic filler and help to move towards sustainability goals. This review starts with an overview of plastic waste generation and recycling techniques. A detailed discussion has been done on manufacturing waste polyolefin-based biocomposites and the effect of various fillers and compatibilizers on different properties. These biocomposites are found to be used for trays, packaging boxes, reusable bags, false ceilings, flooring, boundary walls, tiles, cabinets, chairs, tables, doors, designer pots, and automotive interior applications. In the later section, the scope of additive manufacturing of recycled polyolefin waste-based biocomposites along with their associated problems and their solution is also discussed. This review is concluded with the future potential of polyolefin waste upcycling in the sustainable filler-based biocomposites manufacturing sector.
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•Plastic waste comprises approximately 50% polyolefin waste.•Upcycling plastic waste promotes the circular plastic economy initiative.•Decreased properties after recycling can be enhanced by using proper fillers.•Sustainable filler-based composites discussed due to sustainability concerns.•3D printing of recycled polyolefin composites is one of the promising areas.
Two-dimensional (2D) materials can uniquely span the physical dimensions of a surrounding composite matrix in the limit of maximum reinforcement. However, the alignment and assembly of continuous 2D ...components at high volume fraction remain challenging. We use a stacking and folding method to generate aligned graphene/polycarbonate composites with as many as 320 parallel layers spanning 0.032 to 0.11 millimeters in thickness that significantly increases the effective elastic modulus and strength at exceptionally low volume fractions of only 0.082%. An analogous transverse shear scrolling method generates Archimedean spiral fibers that demonstrate exotic, telescoping elongation at break of 110%, or 30 times greater than Kevlar. Both composites retain anisotropic electrical conduction along the graphene planar axis and transparency. These composites promise substantial mechanical reinforcement, electrical, and optical properties at highly reduced volume fraction.
Rubber promises to be an excellent matrix for heat dissipation composites due to its unique elasticity and flexibility. However, restricted by traditional processing approaches, it remains ...challenging to fabricate high-performance rubber nanocomposites with both good mechanical strength and high thermal conductivity (TC). Herein, we develop a novel GO-assisted gelation method to construct a 3D interconnected rGO@Al2O3 hybrid fillers network as efficient heat transfer path in natural rubber nanocomposite acquiring desirable performance. The as-prepared rubber nanocomposite, at a filler loading of 18.0 vol%, exhibits not only a largely increased tensile strength (25.6 MPa) but also a high TC (0.514 W/(m·K)). Owing to the construction of a highly interconnected filler network, the resulting 3D rGO@Al2O3-NR shows apparently higher TC than the nanocomposites prepared by conventional method at the same filler content. More promisingly, the filler network tends to orient perpendicular to the compressing direction at ultrahigh filler loading, causing surprisingly enhanced in-plane TC which is up to 3.233 W/(m·K) at 33.9 vol% filler content. Moreover, we can easily control electrical resistance by adjusting the mass ratio of GO to Al2O3, making the nanocomposites satisfy the use requirement of electrical insulation. This study provides a creative insight to the design of high-performance rubber nanocomposites with a bright application prospect in advanced heat dissipation materials.
•Alumina-coated graphene oxide hybrid fillers (GO@Al2O3) were fabricated by a facile electrostatic self-assembly method.•Interconnected filler network was constructed successfully in the NR nanocomposite via a novel and simple strategy.•The obtained NR nanocomposite exhibits a high thermal conductivity and excellent mechanical properties.•The volume resistivity of the resulting products is adjustable.
In restorative dentistry, dental composites have become a popular material of choice due to the increasing aesthetic demands and address challenges like recurrent cavities and restorative bulk ...fracture, which are the most common causes of dental composite failure. To address these issues, various types and shapes of reinforcement fillers were researched to enhance the mechanical properties of composite formulations over conventional composites. Furthermore, antibacterial agents and ion-releasing fillers are used to prevent secondary caries and promote the remineralisation of dental tissue. This review article aims to review the literature of dental resin composites, focusing on various filler categories and their impact on the materials' performance, to aid future development of dental resin composites for clinical applications with optimal properties that can overcome current limitations.
Abstract
The requirement for a lightweight bipolar plate (BP) for Proton Exchange Membrane Fuel Cell (PEMFC) is increasing to make it feasible to power hydrogen fuel cell electric vehicles. Composite ...BP with carbon materials as conductive fillers and polymer as the binder are preferable over pure graphite and metallic BP. This study investigates the effect of Surface‐enhanced flake graphite (SEFG) as a novel filler material in composite BP. A composite BP is developed with Epoxy Resin (ER) as the binder and Natural Flake Graphite (NFG), Carbon Black (CB) and SEFG as conductive fillers. Composite BP fabricated with 10 vol% SEFG, 10 vol% CB, and 40 vol% NFG exhibited an electrical conductivity of 158 S cm
−1
, flexural strength of 38 MPa, water contact angle of 90.41
0
and corrosion current density of 0.261 μA cm
−2
. The composite BP also achieved a density of 1.55 g cm
−3
, water absorption of 0.6% and thermal conductivity of 3.6 W m
−1
K
−1
at 120°C. These results are highly favorable for BPs used in PEMFC. This paper provides an insight into using surface‐modified conductive carbon filler materials to develop composite BP for application in PEMFC.
