Resulting Hybrid Composites Research Articles

Hybrid composites based on technical cellulose from rice husk

ABSTRACTWe introduced the preparation of hybrid composites using technical cellulose as a matrix material from rice husks with a natural SiO2 content from 0% to 19.4%. In this work, the physicochemical characteristics of the resulting hybrid composites have been investigated. The presence of SiOC chemical bonds in the resulting hybrid composites was determined by infrared spectroscopy. Microscopic analysis showed the complete removal of the mineral component and lignin from the cell wall of the rice husk fibers. This allows obtaining of an expanded surface of the fibers (101.7 m2/g) with uniform distribution of the TiO2 aggregates. It could be shown that with content increasing of natural silicon dioxide in the hybrid composite the decomposition rate of H2O2 also increases. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45796.

Comparison of two different carbon nanotubes-based hybrid multiscale composites with respect to mechanical and electrical properties

ABSTRACTPristine and carboxylic acid functionalised carbon nanotubes (CNTs-P and CNTs-COOH) hybrid composites based on ultrasonically processed nanocomposite epoxy matrix have been prepared. The thermodynamic interactions between CNTs and epoxy components are evaluated through solution experiment. The measurements of mechanical properties and volume electrical resistivity are performed to characterise the structure-property interplay of CNTs hybrid composites. A 0.3 wt-% CNTs-COOH loading significantly enhances the glass transition temperatures (Tg) of the resultant hybrid composites. The re-agglomeration of CNTs-P has been ascribed to the thermodynamic and kinetic factors, which determine the morphological characteristics of CNTs within the overall composites. CNTs-P network enables a continuous conductive path to be present in the composites at lower CNTs-P concentration. An analysis of the effects of the functionalisation of CNTs on the structure and properties of their hybrid composites has been carried out.

The Mechanical Properties and Microstructure Characters of Hybrid Composite Geopolymers-Pineapple Fiber Leaves (PFL)

The objective of this research is to study the influence of organic fibers on the mechanical properties and microstructure characters of hybrid composite geopolymers-pineapple fibers (PFL). Geopolymers were synthesized by using alkali activated of class C-fly ash added manually with short pineapple fiber leaves (PFL) and then cured at 60°C for 1 hour. The resulting composites were stored in open air for 28 days prior to mechanical and microstructure characterizations. The samples were subjected to compressive and flexural strength measurements, heat resistance as well as acid attack (1M H2SO4 solution). The microstructure of the composites were examined by using Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS). The measurement showed that the addition of pineapple fibers was able to improve the compressive and flexural strength of geopolymers. The resulting hybrid composites were able to resist fire to a maximum temperature of 1500°C. SEM examination showed the presence of good bond between geopolymer matrix and pineapple fibers. It was also found that there were no chemical constituents of geopolymers leached out during acid liquid treatment. It is concluded that hybrid composite geopolymers-pineapple fibers are potential composites for wide range applications.

Hybrid effect of carbon nanotube film and ultrathin carbon fiber prepreg composites

This paper successfully interlaced floating catalyst chemical vapor deposition-grown carbon nanotube film and ultrathin carbon fiber prepreg to achieve strong and flexible carbon nanotube/carbon fiber hybrid composites with high carbon nanotube loading. Epoxidation was also introduced to improve interlaminar interfacial bonding. It was found that pristine carbon nanotube film/carbon fiber interply hybrid composite (carbon fiber/carbon nanotube/carbon fiber) showed sudden and brittle failure, while epoxidation caused a gradual failure behavior. Hybrid effect analysis suggested that the improved tensile performance and synergistic effect of epoxidized carbon nanotube film/carbon fiber hybrid composite were attributed to good load transfer and suppressed delamination induced by improved interfacial bonding. In addition carbon fiber/carbon nanotube/carbon fiber manifested excellent damping capacity with the maximum loss factor of 0.13. The in-plane electrical conductivity of composite with global carbon nanotube content of 21 wt% increased to the same order of magnitude as carbon nanotube film composite. The excellent mechanical, damping, and electrical properties demonstrated great potential for both structural and multifunctional applications of the resultant hybrid composites.

Fabrication and characterization of novel zirconia filled glass fiber reinforced polyester hybrid composites

ABSTRACTNovel hybrid glass fiber reinforced polyester composites (GFRPCs) filled with 1‐5 wt % microsized zirconia (ZrO2) particles, were fabricated by hand lay‐up process followed by compression molding and evaluated their physical, mechanical and thermal behaviors. The consumption of styrene in cured GFRPCs was confirmed by Fourier transform infrared spectroscopy. The potential implementation of ZrO2 particles lessened the void contents marginally and substantially enhanced the mechanical and thermal properties in the resultant hybrid composites. The GFRPCs filled with 4 wt % ZrO2 illustrated noteworthy improvement in tensile strength (66.672 MPa) and flexural strength (67.890 MPa) while with 5 wt % ZrO2 showed 63.93% rise in hardness, respectively, as compared to unfilled GFRPCs. Physical nature of polyester matrix for composites and an improved glass transition temperature (Tg) from 103 to 112 °C was perceived by differential scanning calorimetry thermograms. Thermogravimetric analysis revealed that the thermal stability of GFRPCs was remarkably augmented with the addition of ZrO2. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43615.

Fabrication and electrochemical properties of 3D Fe3O4@graphene aerogel composites as lithium-ion battery anodes

A novel facile strategy was developed to prepare the Fe3O4@graphene aerogel (Fe3O4@GA) composites. Fe3O4 nanoparticles were uniformly dispersed into the 3D network of graphene aerogel and the resultant hybrid composites contained meso- and macro-scale pores with high specific surface area (276.9m2g−1) and large pore volume (0.3230cm3g–1). The electrochemical performance revealed that the Fe3O4@GA anode exhibited high reversible capacity (~941.5mAhg−1 at a current density of 100mAg−1), stable cycling performance, and excellent rate capability.

Water-Soluble Luminescent Hybrid Composites Consisting of Oligosilsesquioxanes and Lanthanide Complexes and their Sensing Ability for Cu(2.).

Water-soluble hybrid composites with great potential for selective and sensitive sensing and that are obtained through simple, rapid, and environmentally friendly methods are highly desirable and remain a challenging task. Herein, we present luminescent hybrid composites that were realized by linking Na3 [Ln(dpa)3 ] (dpa=2,6-pyridinedicarboxylic acid) to octa-amino functionalized polyhedral oligomeric silsesquioxane (POSS-NH2 ) through hydrogen-bonding interactions between the oxygen atoms of the carboxylate groups of dpa and the hydrogen-bond-donor amino groups. The resulting hybrid composites Ln(dpa)3 @POSS-NH2 are highly soluble in aqueous solutions and the quantum yield of Eu(dpa)3 @POSS-NH2 is as high as 56.5 % or 46.3 % in the solid state and in aqueous solution, respectively, as determined by using the integrating sphere method. The novel water-soluble luminescent hybrid composites exhibit high thermal and photostability, and the emitted colors of the resulting hybrid composite can be finely tuned by changing the Eu(3+) /Tb(3+) ratio. Interestingly, Eu(dpa)3 @POSS-NH2 hybrid composites exhibited an effective switch-off fluorescence response to Cu(2+) over other common metal ions in aqueous media.

Crown-Ether Derived Graphene Hybrid Composite for Membrane-Free Potentiometric Sensing of Alkali Metal Ions.

We report the design and synthesis of newly functionalized graphene hybrid material that can be used for selective membrane-free potentiometric detection of alkali metal ions, represented by potassium ions. Reduced graphene oxide (RGO) functionalized covalently by 18-crown[6] ether with a dense surface coverage is achieved by the introduction of a flexible linking molecule. The resulting hybrid composite is highly stable and is capable of detecting potassium ions down to micromolar ranges with a selectivity over other cations (including Ca(2+), Li(+), Na(+), NH4(+)) at concentrations up to 25 mM. This material can be combined further with disposable chips, demonstrating its promise as an effective ion-selective sensing component for practical applications.

Guided in Situ Polymerization of MEH-PPV in Mesoporous Titania Photoanodes

Incorporation of conjugated polymers into porous metal oxide networks is a challenging task, which is being pursued via many different approaches. We have developed the guided in situ polymerization of poly(2-methoxy-5-(2'-ethylhexyloxy)-p-phenylenevinylene) (MEH-PPV) in porous titania films by means of surface functionalization. The controlled polymerization via the Gilch route was induced by an alkoxide base and by increasing the temperature. The selected and specially designed surface-functionalizing linker molecules mimic the monomer or its activated form, respectively. In this way, we drastically enhanced the amount of MEH-PPV incorporated into the porous titania phase compared to nonfunctionalized samples by a factor of 6. Additionally, photovoltaic measurements were performed. The devices show shunting or series resistance limitations, depending on the surface functionalization prior to in situ polymerization of MEH-PPV. We suggest that the reason for this behavior can be found in the orientation of the grown polymer chains with respect to the titania surface. Therefore, the geometry of the anchoring via the linker molecules is relevant for exploiting the full electronic potential of the conjugated polymer in the resulting hybrid composite. This observation will help to design future synthesis methods for new hybrid materials from conjugated polymers and n-type semiconductors to take full advantage of favorable electronic interactions between the two phases.

Carbon Fiber/Carbon Nanotube Buckypaper Interply Hybrid Composites: Manufacturing Process and Tensile Properties

This paper reports on a study of carbon nanotube (CNT) thin film, or buckypaper (BP), integrated into carbon fiber (CF) prepreg composites to create hybrid composite materials with high CNT content. The autoclave process of manufacturing hybrid composite laminates was investigated to gain an understanding of nano/micro dual‐scale resin flow characteristics. The study found that resin bleeding along the through‐thickness direction was inhibited due to extra‐low permeability and high resin absorbing capacity of the BP. Resin matrix‐impregnated BP layers were much thicker than dry pristine BP due to high resin absorbency and swelling effects. The BP/unidirectional carbon fiber (UD‐CF) hybrid composites with local fiber volume fraction of 61.46 vol% in CF ply and local CNT volume fraction of 26.57 vol% in BP layer, had a tensile strength of 2519 ± 101 MPa and modulus of 149 ± 18 GPa. The dramatic improvements in both in‐plane and through‐thickness electrical conductivities demonstrate potential for both structural and multifunctional applications of the resultant hybrid composites.

Biodegradable <i>Sansevieria cylindrica</i> Leaves Fiber/Tamarind Fruit Fiber Based Polymer Hybrid Composites on Characterization

This paper deals with the preparation and characterization of epoxy tamarind fruit (Tf) and Sansevieria cylindrica (Sc) hybrid composites containing fiber 0:20, 5:15, 10:10, 15:5 and 20:0 of (Tf:Sc) combinations loading. Sansevieria cylindrica leaves were used in this paper for extracting fiber out of it and in the similar manner ripen Tamarind fruit was used to extract fiber. Two different fibers viz. tamarind fruit/ Sansevieria cylindrica fibers were loaded into the epoxy system to develop the hybrid composites. The tensile and flexural properties of the resulting 20 wt. % loading of Tf/Sc/epoxy hybrid composites were examined. The resulting hybrid composites of 20 wt. % Tf/Sc with varying combinations exhibit the optimum improvement of mechanical properties and dielectric strength. 2 °C rise in decomposition temperature and 5 °C rise glass transition temperature were observed from the TGA and DSC thermal analysis. The fractured cross sections of flexural samples were assessed their performance as a function of fiber loading of Tf/Sc/epoxy hybrid composites by SEM analysis.

Biodegradable <i>Sansevieria cylindrica</i> Leaves Fiber/Tamarind Fruit Fiber Based Polymer Hybrid Composites on Characterization

This paper deals with the preparation and characterization of epoxy tamarind fruit (Tf) and Sansevieria cylindrica (Sc) hybrid composites containing fiber 0:20, 5:15, 10:10, 15:5 and 20:0 of (Tf:Sc) combinations loading. Sansevieria cylindrica leaves were used in this paper for extracting fiber out of it and in the similar manner ripen Tamarind fruit was used to extract fiber. Two different fibers viz. tamarind fruit/ Sansevieria cylindrica fibers were loaded into the epoxy system to develop the hybrid composites. The tensile and flexural properties of the resulting 20 wt. % loading of Tf/Sc/epoxy hybrid composites were examined. The resulting hybrid composites of 20 wt. % Tf/Sc with varying combinations exhibit the optimum improvement of mechanical properties and dielectric strength. 2 °C rise in decomposition temperature and 5 °C rise glass transition temperature were observed from the TGA and DSC thermal analysis. The fractured cross sections of flexural samples were assessed their performance as a function of fiber loading of Tf/Sc/epoxy hybrid composites by SEM analysis.

Preparation and properties of hierarchical composites based on carbon nanotubes‐coated glass babric preform

A strategy based on carbon nanotubes (CNTs)‐containing sizing dispersion has been implemented to fabricate nanocomposite preforms and their hybrid multiscale composites. The state of pristine CNTs and carboxylic acid functionalized CNTs (CNTs–COOH) in sizing dispersion was effectively monitored by on‐line measuring electrical conductivity. The effects of different CNTs coating applied onto glass fabric on wettability of nanocomposite fibrous reinforcement with epoxy matrix were evaluated using scanning electron microscopy and capillary experiment. A CNTs‐COOH loading of 0.5 wt% gave rise to 97% and 30°C increases in the storage modulus (G′) and glass transition temperature of the resulting hybrid composites, respectively. The enhanced thermomechanical properties of the CNTs hybrid composites are closely related to the stable CNTs sizing dispersion and uniform coating onto fiber reinforcement. The mechanism for reinforcing composites through toughening resin region with CNTs desorbing from primary fiber surface during impregnation has been identified. POLYM. COMPOS. 37:979–986, 2016. © 2014 Society of Plastics Engineers

Solid Particle Erosion Behavior of BFS-Filled Epoxy–SGF Composites Using Taguchi's Experimental Design and ANN

The target of this experimental study is to investigate the solid particle erosion behavior of a new composite material formed by adding blast furnace slag (BFS) particles at different amounts of 0, 10, 20, 30 wt% to short glass fiber (SGF)-reinforced epoxy resin. The resulting hybrid composites are subjected to solid particle erosion using an air jet–type erosion test rig. Erosion tests are carried out by following a well-designed experimental schedule based on Taguchi's orthogonal array. BFS content, impact velocity, and impingement angle are identified as the significant factors affecting the erosion rate of the composites. A prediction model based on an artificial neural network (ANN) is proposed to predict the erosion performance of these composites under a wide range of erosive wear conditions. This model is based on the database obtained from the experiments and involves training, testing, and prediction protocols. The work shows that an ANN model helps in saving time and resources that are required for a large number of experimental trials and successfully predicts the erosion rate of composites both within and beyond the experimental domain.

Artificial enzyme with magnetic properties and peroxidase activity on indoleamine metabolite tumor marker

Stable and easily-handled synthetic materials mimicking natural enzymes activity would find important biotechnological applications. This article describes the synthesis and characterization of magnetic molecularly imprinted catalytic polymers that exhibit peroxidase-like activity towards 5-hydroxyindole-3-acetic acid (5-HIAA) oxidation. This multifunctional material is obtained from highly crystalline magnetite nuclei coated with a silica layer to protect the iron nucleus from oxidation and to provide anchoring for hydroxyl surface groups. After acrylic functionalization via sol–gel process, a molecularly imprinted polymer with hemin as catalytic center and 5-HIAA as template has been successfully attached to the structure. The resulting hybrid composite is magnetically separable and possesses excellent catalytic ability for the selective oxidation of the indoleamine metabolite tumor marker, showing Michaelis–Menten kinetics with this molecule but not towards other structural analogs. Therefore, it can be considered an artificial peroxidase enzyme.

Simultaneous reinforcement and toughening of polyurethane composites with carbon nanotube/halloysite nanotube hybrids

Abstract In this work, three-dimensional (3D) hybrid nanofillers, composed of acid-treated multi-walled carbon nanotubes (a-CNTs) and silane-treated halloysite nanotubes (s-HNTs), have been successfully prepared through covalent bonding. By using simple solution-casting method, polyurethane (PU) elastomers reinforced with these s-HNT/a-CNT (HC) hybrid nanofillers have been fabricated. The morphology and mechanical properties of the resultant hybrid and PU composites are characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), thermogravimetric analysis (TGA) and tensile tests. Tensile test data show that the tensile strength, Young’s modulus and elongation at break of the resultant PU composite with merely 1 wt% HC hybrids are significantly improved by 140%, 35% and 68% respectively. This clearly demonstrates the synergistic reinforcement of one-dimensional CNTs and HNTs within the hybrid in improving the strength and toughness of PU composite. Therefore, the s-HNT/a-CNT hybrid thus prepared is an ideal agent for simultaneous reinforcement and toughening of PU elastomers.

Performance enhancement of nylon/kevlar fiber composites through viscoelastically generated pre‐stress

Kevlar‐29 fibers have high strength and stiffness but nylon 6,6 fibers have greater ductility. Thus by commingling these fibers prior to molding in a resin, the resulting hybrid composite may be mechanically superior to the corresponding single fiber‐type composites. The contribution made by viscoelastically generated pre‐stress, via the commingled nylon fibers, should add further performance enhancement. This paper reports on an initial study into the Charpy impact toughness and flexural stiffness of hybrid (commingled) nylon/Kevlar fiber viscoelastically pre‐stressed composites at low fiber volume fractions. The main findings show that (i) hybrid composites (with no pre‐stress) absorb more impact energy than Kevlar fiber‐only composites; (ii) pre‐stress further increases impact energy absorption in the hybrid case by up to 33%; (iii) pre‐stress increases flexural modulus by ∼40% in the hybrid composites. These findings are discussed in relation to practical composite applications. POLYM. COMPOS., 35:931–938, 2014. © 2013 Society of Plastics Engineers

Rheological and Tribological Properties of Carbon Nanotube/Thermoplastic Nanocomposites Incorporating Inorganic Fullerene-Like WS2 Nanoparticles

The rheological and tribological properties of single-walled carbon nanotube (SWCNT)-reinforced poly(phenylene sulphide) (PPS) and poly(ether ether ketone) (PEEK) nanocomposites prepared via melt-extrusion were investigated. The effectiveness of employing a dual-nanofiller strategy combining polyetherimide (PEI)-wrapped SWCNTs with inorganic fullerene-like tungsten disulfide (IF-WS2) nanoparticles for property enhancement of the resulting hybrid composites was evaluated. Viscoelastic measurements revealed that the complex viscosity η, storage modulus G', and loss modulus G″ increased with SWCNT content. In the low-frequency region, G' and G″ became almost independent of frequency at higher SWCNT loadings, suggesting a transition from liquid-like to solid-like behavior. The incorporation of increasing IF-WS2 contents led to a progressive drop in η and G' due to a lubricant effect. PEEK nanocomposites showed lower percolation threshold than those based on PPS, ascribed to an improved SWCNT dispersion due to the higher affinity between PEI and PEEK. The SWCNTs significantly lowered the wear rate but only slightly reduced the coefficient of friction. Composites with both nanofillers exhibited improved wear behavior, attributed to the outstanding tribological properties of these nanoparticles and a synergistic reinforcement effect. The combination of SWCNTs with IF-WS2 is a promising route for improving the tribological and rheological performance of thermoplastic nanocomposites.

Polylactide-Based Wood Plastic Composites Toughened with SBS

Wood plastic composites (WPCs) composed of polylactide (PLA), pine wood flour (WF), and SBS were successfully manufactured through extrusion blending followed by injection molding. The impact strength and elongation at the break of the PLA-based WPCs toughened with SBS were higher than their non-toughened counterparts, in contrast to the decrease in the tensile strength. There was a percolation process in brittle-ductile transition of the impact strength for the SBS-toughened WPCs when the WF content was between 15 and 35 wt%. TGA indicated that SBS had no significant effect on the thermal stability of the resulting hybrid composites.

Mechanical and electrical properties of carbon nanotube/poly(phenylene sulphide) composites incorporating polyetherimide and inorganic fullerene-like nanoparticles

The mechanical and electrical properties of single-walled carbon nanotube (SWCNT) reinforced poly(phenylene sulphide) (PPS) composites prepared by melt-extrusion have been evaluated. The wrapping of SWCNTs in polyetherimide (PEI) and the addition of inorganic fullerene-like tungsten disulfide (IF-WS2) nanoparticles provided an effective method for dispersing the SWCNTs, leading to enhanced properties of the resulting hybrid composites. Mechanical tests demonstrated significant enhancements in stiffness, strength and toughness by the addition of both nanofillers, and the Young’s modulus of the hybrid composites was fairly well predicted by two-phase modelling. The electrical conductivity of PPS improved dramatically at low SWCNT content (0.1–0.5wt%). At higher concentrations, the replacement of part of the SWCNTs with IF-WS2 maintained the level of conductivity of the composites. Overall, the hybrids possess superior performance than composites reinforced solely with wrapped or non-wrapped SWCNTs, and their properties can be tailored by modifying the SWCNT/IF-WS2 ratio.