Reinforcement Filler Research Articles

Preliminary Study of Potential Bioimplant from Glycerol Plasticized Starch-Microcrystalline Cellulose Composite

Biodegradable and bio-based substitutes for conventional plastics are on the rise in these past decades. One of the applications of bioplastic is for biomedical implants or bioimplant. Starch was plasticized using glycerol at varying amounts (40% and 60% of dry starch mass) to produce thermoplastic starch (TPS). A reinforcement filler of microcrystalline cellulose (MCC) was used to improve the mechanical properties. The MCC content in this study was also varied (0%, 2%, 4%, and 8% w/w). This paper studies the mechanical properties of starch-MCC composites for their potential as bioimplant. The optimum glycerol and MCC contents from the results are 40% glycerol and 8% MCC with 2.97 MPa tensile strength and 7.20% strain at break. Thus, the sample has the potential application in bioimplant material for trabecular bone replacement, which has an average tensile strength of 2 MPa and strains at a break of 2.5%.

Hyaluronic acid hydrogels reinforced with laser spun bioactive glass micro- and nanofibres doped with lithium

The repair of articular cartilage lesions in weight-bearing joints remains as a significant challenge due to the low regenerative capacity of this tissue. Hydrogels are candidates to repair lesions as they have similar properties to cartilage extracellular matrix but they are unable to meet the mechanical and biological requirements for a successful outcome. Here, we reinforce hyaluronic acid (HA) hydrogels with 13-93-lithium bioactive glass micro- and nanofibres produced by laser spinning. The glass fibres are a reinforcement filler and a platform for the delivery of therapeutic lithium-ions. The elastic modulus of the composites is more than three times higher than in HA hydrogels. Modelling of the reinforcement corroborates the experimental results. ATDC5 chondrogenic cells seeded on the composites are viable and more proliferation occurs on the hydrogels containing fibres than in HA hydrogels alone. Furthermore, the chondrogenic behavior on HA constructs with fibres containing lithium is more marked than in hydrogels with no-lithium fibres.

Recent Advances in Geopolymer Technology. A Potential Eco-Friendly Solution in the Construction Materials Industry: A Review

In the last ten years, the Portland cement industry has received wide criticism due to its related high embodied energy and carbon dioxide footprint. Recently, numerous “clean” strategies and solutions were developed. Among these, geopolymer technology is gaining growing interest as a functional way to design more eco-friendly construction materials and for waste management issues suffered by various industries. Previous research has highlighted the attractive engineering properties of geopolymeric materials, especially in terms of mechanical properties and durability, resulting in even higher performance than ordinary concrete. This review provides a comprehensive analysis of current state-of-the-art and implementations on geopolymer concrete materials, investigating how the key process factors (such as raw materials, synthesis regime, alkali concentration, water dosage, and reinforcement fillers) affect the rheological, microstructural, durability, and mechanical properties. Finally, the paper elucidates some noteworthy aspects for future research development: innovative geopolymer-based formulations (including alkali-activated blends for additive manufacturing and thermo-acoustic insulating cellular compounds), concrete applications successfully scaled in the civil-architectural fields, and the perspective directions of geopolymer technology in terms of commercialization and large-scale diffusion.

CLAY BRICK WASTE: NEW FILLER TO NATURAL RUBBER COMPOSITE

The development of urban cities increases the amount of construction and demolition waste, such as ceramic materials, mainly clay bricks, and consequently, generates cost for the management and environmental disposal due to the few routes to recycle or reuse them. Here, it is proposed a new approach to reuse clay bricks waste (CB) composed by red ceramic as a reinforcement filler to natural rubber (NR) composites. It was verified that the residue is mostly composed of silicon, which is a filler widely used in rubber industry as SiO2, to mechanically reinforce composites. Tensile strength showed an increment around 16% when 20 phr of CB waste was added to the natural rubber (reaching 12,4 MPa). In addition, composites with 10 phr of waste showed great abrasion resistance and the hardness property increased as CB waste was added. The results indicate that the residue can be used as a possible filler in natural rubber products.

Impact of nanoclay filler reinforcement on CFRP composite performance during abrasive water jet machining

ABSTRACT This paper aims to examine the influence of nanoclay as secondary reinforcement in carbon epoxy (CFRP) composite on the abrasive water jet machining (AWJM) response for the process parameters, namely, jet pressure (96 and 304 MPa), traverse rate (50, 100, and 150 mm/min), and nanoclay (0.00, 1.25, and 2.50 wt%). The most dominating parameters for AWJM response such as average surface roughness (Ra) characteristics, kerf taper (KT) formation, and material removal rate (MRR) of CFRP plates were investigated by adopting the Taguchi-based statistical method. ANOVA was utilized to obtain the influence of input factors on the process response. Traverse rate was attained as the most considerable factor for all the AWJM response. CFRP embedded with nanoclay showed relatively lower KT formation, Ra, and MRR than the CFRP laminate without nanoclay. Traverse rate with 150 mm/min showed higher Ra, KT formation and MRR compared to 50 and 100 mm/min. Jet pressure with 304 MPa showed lower Ra and KT formation while provided better MRR. The microstructure analysis of the machined surface was illustrated applying FESEM.

Thermally Conductive Electrically Insulative (TCEI) Materials for E-Motors

<div class="section abstract"><div class="htmlview paragraph">Engineering plastics are often used in electric components and systems. For these materials, many requirements such as electrical resistance, mechanical properties, temperature capability, flammability, thermal conductivity, moldability etc. are considered for material selection. In general plastics are good electric insulators (electrically safe) but poor conductors of heat (compared to metals). In electric motors, losses due to friction, windage losses, winding losses, iron losses etc. manifest as undesirable heat, resulting in temperature buildup inside the motor. So, choice of materials which offer high thermal conduction and electrical insulation can directly impact motor performance.</div><div class="htmlview paragraph">Material properties of engineering plastics are greatly influenced by the filler reinforcements used. Although unfilled polymers typically have a thermal conductivity of ~0.2 W/m/K, appropriate choice of fillers can increase this value many-fold. One of the challenges with injection molded plastics is that material properties, including thermal conductivity, are a function of material orientation (orthotropic). In the present work, TCEI materials have been developed for use in bobbins. Freudenberg Sealing Technologies, with its knowledge of filled polymeric systems has developed multiple TCEI grades with improved thermal conductivity compared to commercially available materials. Thermal conductivity measurements on these novel material grades have been conducted to quantify improvements. A finite element model has been developed to capture effect of material choice on temperature distribution within the system. The model incorporates varying material orientation within the bobbin and components within the motor and uses temperature dependent material properties for the analysis. The effect of varying thermal conductivity values on thermal performance and influence of an air gap are studied. Results show that materials with improved thermal conductivity show reduced bobbin and winding temperatures, offering significant performance benefits.</div></div>

Nanoparticles Addition in Coir‐Basalt‐Innegra Fibers Reinforced Bio-synthetic Epoxy Composites

In the present investigation, the influence of coir micro-particles and titanium carbide (TiC) nanofillers on mechanical characteristics and thermal stability of basalt-Innegra fiber-reinforced bio/synthetic epoxy hybrid composites were studied. The mechanical, thermal and physical properties (water absorption, surface wettability, and porosity) were determined. Characterization techniques such as SEM, TGA, and FTIR spectra have been performed to investigate the modification in the structure of epoxy hybrid composites. From the results, it was found that the reinforcement of TiC nanofillers and coir fiber micro-particles in basalt-Innegra fiber reinforced epoxy composites exhibited a significant increment in thermal stability and mechanical properties with the efficient load transfer between the matrix, fillers, and fabrics. Furthermore, the addition of coir micro-particles and TiC nanofillers as an intrinsic reinforcement filler positively influence the thermal stability of epoxy hybrid laminates reinforced with basalt and Innegra fabrics.

Preparation of graphene/copper nanocomposites by ball milling followed by pressureless vacuum sintering

Graphene has been considered as an ideal reinforcement filler for metal matrix composites because of its ultra-high strength and stiffness, and exceptional thermal and electrical properties. Graphene-reinforced copper (Gr/Cu) nanocomposites were fabricated by ball milling followed by pressureless vacuum sintering, and were characterized by SEM, TEM, XRD, Raman spectroscopy and mechanical tests. Results indicate that the graphene platelets are well dispersed in the nanocomposites without apparent damage. The graphene filler dramatically improves the hardness and reduces the coefficient of friction of the Gr/Cu nanocomposites compared to pure Cu.

The Characteristics of Natural Rubber Composites with Klason Lignin as a Green Reinforcing Filler: Thermal Stability, Mechanical and Dynamical Properties.

The objective of this work was to investigate the influences of Klason lignin as a filler on the thermal stability and properties of natural rubber composites. The modulus and tensile strength of stabilized vulcanizates were measured before and after thermo-oxidative aging. It was determined that lignin filled natural rubber had significantly enhanced thermo-oxidative aging and mechanical properties compared to those of controlled samples. The reinforcement effect of lignin increased stress with lignin loading but it decreased at 20 phr, suggesting that the reinforcement mechanism of lignin was via strain-induced crystallization. The composite samples with 10 phr filler loading had the highest mechanical properties as well as thermo-oxidative degradation resistance. Such a finding could be due to interactions between the Klason lignin filler and natural rubber matrix. Based on the findings in this work, the degradation temperature of Klason lignin occurred at 420 °C. The absorption peaks at wavenumbers 1192 and 1374 cm−1 indicated that C–O stretching vibrations of the syringyl and guaiacyl rings of hardwood lignin existed. It was also found that the Klason lignin–rubber composite containing 10 phr had the highest stress–strain, 100% modulus, and tensile strength, while lignin showed increasing aging resistance of the composite comparable with commercial antioxidant at 1.5 phr. It appears that Klason lignin from rubberwood could be used as a green antioxidant and alternative reinforcing filler and for high performance eco-friendly natural rubber biocomposites.

High-Strength Poly(ethylene oxide) Composite Electrolyte Reinforced with Glass Fiber and Ceramic Electrolyte Simultaneously for Structural Energy Storage

The development of structural energy-storage materials is critical for the lightweighting and space utilization of electric vehicles and aircrafts. However, a structural electrolyte suitable for structural energy devices is rarely exploited. Here, a structural lithium battery composed of a fiber-reinforced structural electrolyte and a structural cathode is demonstrated. Benefitting from poly(ethylene oxide)–lithium bis(trifluoromethane)sulfonimide (PEO-LiTFSI) as the polymer electrolyte matrix and lithium aluminum titanium phosphate (LATP) and glass fiber (GF) as reinforcement fillers, the LATP-GF/PEO-LiTFSI composite electrolyte developed offers a high tensile strength of 33.1 MPa, large Li+ transfer number of 0.37, moderate ionic conductivity of 6.3 × 10–5 S cm–1 (at 25 °C), wide electrochemical window of 4.4 V, and high effectiveness in suppression of lithium dendrite growth. Finally, a structural lithium battery is demonstrated with acidified carbon fibers (ACFs) as the cathode, Li as the anode, and LATP-GF/PEO-LiTFSI as the electrolyte, which shows an ultrahigh tensile strength of 124.2 MPa and a moderate capacity of 1.45 mAh cm–2. Importantly, the ACF|LATP-GF/PEO-LiTFSI|Li cell can properly function under a high compressive stress of 11.26 MPa. It is believed that the design strategy with a fiber-reinforced polymer as the structural electrolyte and a carbon fiber woven fabric as the structural electrode is feasible to obtain high-performance structural energy-storage components.

Multifunctional Mg/Al layered double hydroxides intercalated by sorbate anion via low-cost co-precipitation

Layered double hydroxides intercalated with sorbate anion (SLDHs) was a potential material for sorbic acid controlled-releasing, UV barrier, reinforcement of rubber and flame retardancy filler. The addition reactions of sorbate anion (SAa) with ethylene and H radical were calculated as spontaneous on B3LYP/6–311++ (d, p) theory level by GAMESS-US and the electrostatic potential (ESP) of SAa was calculated by Multiwfn package and figured by VMD. SLDHs was successfully synthesized by co-precipitation with chlorides, and intercalating way of SAa was first constructed by electrostatic potential analysis, and then the successful intercalation of SAa was confirmed by X-ray diffractions (XRD) and Fourier transform infrared spectroscopy (FTIR). SLDHs possessed assembled flaky morphology and have good thermal stability with a water contact angle near 95°. This study may have a significance on the promotion of the scale application of SLDHs practically.

Alkynyl-functionalization of carbon nanotubes to promote anchoring potential in glycidyl azide polymer-based binders via Huisgen reaction for solid propellant application

Triazole curing systems based on glycidyl azide polymer (GAP) have been widely used as the binders of solid propellant systems due to moisture insensitivity, high energy density, and room temperature curing. However, the low-flexible molecular structure of GAP usually causes low mechanical properties, and reinforcement fillers may not be suitable in the binder system of propellants because they probably diffuse into other parts of propellants. Thus, we anchored a strong nanomaterial, carbon nanotube (CNT), on GAP to prevent the CNT from diffusing uncontrollably. The anchoring process was based on the alkynylation reaction and the Huisgen reaction, which was confirmed by tests on chemical structure. The reaction process was further adjusted to introduce CNT into the triazole crosslinked network, leading to a 23.6% increase in the elongation at break of the binder. The high rigidity of CNT also improved the Young’s modulus and tensile strength of the binder increased by 107.7% and 199.0%, respectively. Furthermore, the high thermal conductivity of CNT could reduce the thermal resistance index of the binders from 160.4 °C to 151.2 °C, and decrease the carbon residue rate from 17.8% to 10.5%. Such an anchoring modification can thus target the reinforcement region in multi-component systems, which can be used not only in solid propellants, but also in ablative materials.

Development of biomaterial fillers using eggshells, water hyacinth fibers, and banana fibers for green concrete construction

Water hyacinth fiber, banana fiber, and eggshell powder were used as biomaterial fillers for concrete reinforcement, obtained from agricultural and post-consumer wastes. Adding the 0.02 and 0.05 ratios (by weight) of bio-fillers into concrete enhanced the physical (water absorption, bulk density, and true density) and mechanical properties (compressive strength, tensile strength, flexural strength, and maximum load) of seven experimentally obtained concrete formulas. These results demonstrated that the optimum formulas of a concrete composite were obtained upon adding the 0.05 ratio (by weight) of eggshell powder followed by curing for 28 d. The best bio-filler for concrete composite is adding eggshell powder. The bulk density, true density, water absorption, compressive strength, tensile strength, flexural strength, and maximum load of concrete Formula 6 (obtained by mixing 0.05 ratio (by weight) of eggshell powder) are 2.245 ± 0.040 g/cm3, 2.252 ± 0.033 g/cm3, 1.62% ± 0.16%, 22.08 ± 0.66 MPa, 157.33 ± 35.63 MPa, 4.13 ± 0.21 MPa, and 55.68 ± 1.64 kN, respectively. Furthermore, the microstructure and phase formations of the concrete composites were analyzed by SEM and XRD.

Coir Fibers Treated with Henna as a Potential Reinforcing Filler in the Synthesis of Polyurethane Composites

In this study, coir fibers were successfully modified with henna (derived from the Lawsonia inermis plant) using a high-energy ball-milling process. In the next step, such developed filler was used as a reinforcing filler in the production of rigid polyurethane (PUR) foams. The impact of 1, 2, and 5 wt % of coir-fiber filler on structural and physico-mechanical properties was evaluated. Among all modified series of PUR composites, the greatest improvement in physico-mechanical performances was observed for PUR composites reinforced with 1 wt % of the coir-fiber filler. For example, on the addition of 1 wt % of coir-fiber filler, the compression strength was improved by 23%, while the flexural strength increased by 9%. Similar dependence was observed in the case of dynamic-mechanical properties—on the addition of 1 wt % of the filler, the value of glass transition temperature increased from 149 °C to 178 °C, while the value of storage modulus increased by ~80%. It was found that PUR composites reinforced with coir-fiber filler were characterized by better mechanical performances after the UV-aging.

Homogeneous distribution of lignin/graphene fillers with enhanced interlayer adhesion for 3D printing filament

AbstractThe attention to pursuing biodegradable fillers as reinforcement in three‐dimensional (3D) printing filament and enhancing interlayer adhesion has led to the exploitation of agricultural biomass. In this study, organosolv lignin fillers can act as the aforementioned twofold purposes in preparing acrylonitrile butadiene styrene (ABS) filament for fused deposition modeling (FDM). In this study, the lignin polymer composites were homogenized with graphene nanoplatelets (GnPs) as a reinforcer. Essentially, ABS 3D printing at 90o with the reinforcement fillers shows a significant increment in the mechanical properties owing to better interlayer adhesion. The printed product promotes a substantial improvement on the tensile stress up to 29.1% compared with neat polymers. Furthermore, 3D printing using lignin/GnP composite filaments shows the feasibility of biofillers to be used as filaments for FDM 3D printing of complex geometries even though the surface finish has been affected.

Nature of Carbon Black Reinforcement of Rubber: Perspective on the Original Polymer Nanocomposite.

Adding carbon black (CB) particles to elastomeric polymers is essential to the successful industrial use of rubber in many applications, and the mechanical reinforcing effect of CB in rubber has been studied for nearly 100 years. Despite these many decades of investigations, the origin of stiffness enhancement of elastomers from incorporating nanometer-scale CB particles is still debated. It is not universally accepted whether the interactions between polymer chains and CB surfaces are purely physical adsorption or whether some polymer–particle chemical bonds are also introduced in the process of mixing and curing the CB-filled rubber compounds. We review key experimental observations of rubber reinforced with CB, including the finding that heat treatment of CB can greatly reduce the filler reinforcement effect in rubber. The details of the particle morphology and surface chemistry are described to give insights into the nature of the CB–elastomer interfaces. This is followed by a discussion of rubber processing effects, the influence of CB on crosslinking, and various chemical modification approaches that have been employed to improve polymer–filler interactions and reinforcement. Finally, we contrast various models that have been proposed for rationalizing the CB reinforcement of elastomers.

Influence of Dual Filler Reinforcement on the Curing and Tribo-Mechanical Behaviour of Natural Rubber Nanocomposite for Tire Tread Application

Influence of Dual Filler Reinforcement on the Curing and Tribo-Mechanical Behaviour of Natural Rubber Nanocomposite for Tire Tread Application

Enhancement of Mechanical Behavior of PLA Matrix Using Tamarind and Date Seed Micro Fillers

ABSTRACT This paper reports the mechanical properties of PLA composites incorporated with tamarind and date seed Micro fillers. The composites were manufactured through compression molding technique. The tensile results showed that the seed filler reinforcement has significantly improved the tensile strength of PLA matrix. The particulate reinforcements of both tamarind and palm almost doubled the flexural and impact strength of PLA matrix. Moreover, the date seed powder incorporated composites showed 34.68% improvement in micro hardness but the tamarind seed powder composite showed only marginal improvement (9.82%) when compared with neat PLA. Furthermore, the outcomes revealed that the wt.% of fillers play a noteworthy role in deciding the properties of the PLA composites.

Enhanced electrical and thermal properties of semi-conductive PANI-CNCs with surface modified CNCs.

Cellulose nanocrystals (CNCs) are the most commonly used natural polymers for biomaterial synthesis. However, their low dispersibility, conductivity, and poor compatibility with the hydrophobic matrix hinder their potential applications. Therefore, we grafted sulfate half-ester and carboxylic functional groups onto CNC surfaces (S-CNC and C-CNC) to overcome these shortcomings. The effect of the dopants, surfactant ratios, and properties of CNCs on the thermal stability, conductivity, and surface morphology of polyaniline (PANI)-doped CNC nanocomposites were investigated through emulsion and in situ polymerization. The higher electrical conductivity and well-dispersed morphology of SCNC–PANI30 (1.1 × 10−2 S cm−1) but lower thermal stability than that of CCNC–PANI30 (T0: 189 °C) nanocomposites are highly related to dispersibility of S-CNCs. However, after 4-dodecylbenzenesulfonic acid (DBSA) was added, the conductivity and thermal stability of SCNC/PANI increased up to 2.5 × 10−1 S cm−1 and 192 °C with almost no particle aggregation because of the increase in charge dispersion. The proposed biodegradable, renewable, and surface-modified S-CNC and C-CNC can be used in high-thermal-stability applications such as food packaging, optical films, reinforcement fillers, flexible semiconductors, and electromagnetic materials.

Polymer-mediated interaction between nanoparticles during hydration and dehydration: a small-angle X-ray scattering study.

Polymer-mediated interactions such as DNA-protein binding, protein aggregation, and filler reinforcement in polymers play crucial roles in many important biological and industrial processes. In this work, we report a detailed investigation of interactions between nanoparticles in the presence of high volume fractions of an adsorbing polymer. Small-angle X-ray scattering (SAXS) revealed the existence of a stable gel-like structure in the polymer-nanoparticle dispersion, whereby anchored polymer molecules on nanoparticles acted as bridging centres, while basic interactions between nanoparticles remained repulsive. Time-resolved SAXS measurements showed that the local volume fraction of nanoparticles increased during the drying of the dispersion owing to the shrinkage of the gel-like structure. Further, nanoparticle clusters in the dehydrated composite films showed percolated networks of nanoparticles, except for 5% loading that showed a phase-separated morphology as the volume fraction of nanoparticles remained lower than the percolation threshold. A significant restructuring of nanoparticle clusters occurred upon the hydration of nanocomposite films caused by the expansion of polymer networks induced by hydration forces. Temporal evolution of the volume fraction of nanoparticles during dehydration unveiled three distinct stages similar to the logistic growth function and this was attributed to the evaporation of free, intermediate, and bound water in the different stages. A plausible mechanism was elucidated based on the spring action analogy between anchored polymer chains and nanoparticles during hydration and dehydration processes.