Efficient Filler Research Articles

A New Formulation for Polymeric Separator Gels for Potential use in Blood Serum Separator Tubes

Blood serum separator tubes (SST) are used for collecting blood samples for performing clinical chemistry assays. Some SST's have separator gels inside the tube which enable them better separation of the blood serum from packed cells during centrifugation. The cost, weak performance and interaction with blood ingredients are the most concerns of the available commercial gels. A commercial and cheap silicone oil as a polymeric base of the gel was chosen and formulated without and with several fillers. Subsequently, the compounds were crosslinked through a free radical crosslinking mechanism using dicumyl peroxide (DCP). The crosslinking took place in both, an oven and as well as under microwave irradiation in normal and under pressure conditions. The FTIR spectrometer analysis showed that both chain ends of the used silicone oil were terminated with a vinyl group. It also revealed that blood serum separator gel can be produced from selected silicone oil type. Among of different curing apparatus, curing in an oven was preferred due to less curing time and electrical energy consumption. The curing in normal pressure showed better results when compared with curing under pressure. Increasing the filler and DCP with various amounts had positive effect on gel densities. Silica was the most efficient filler among of the studied fillers. The cured compound filled with 10 and 8 phr silica and DCP, respectively, was chosen as appropriate gel for SST due to suitable density and thixotropy. The selected gel was cured in oven under normal pressure for 30 minutes at 160°C.

Investigation of the size effect of graphene nano-platelets (GnPs) on the anti-corrosion performance of polyurethane/GnP composites.

In this article, polyurethane/graphene nano-platelet (PU/GnP) composites were fabricated via planetary centrifugal mixer (PCM) and cast on polyethylene terephthalate (PET) and copper substrates. Four different grades of GnP are used to investigate the effect of GnP size on the anti-corrosion performance of the composites. Tafel, Nyquist, and Bode plots are used to quantify and compare the anti-corrosion performance of the composites, and these plots are obtained by electrochemical analysis. In addition to the anti-corrosion performance, mechanical properties and morphologies of the composites are analyzed. Various parameters indicating the anti-corrosion performance illustrate that smaller size of GnP in the composites shows higher anti-corrosion performance on copper substrate. The results show that the smaller size of GnP is not only uniformly dispersed within PU, but also offers a high surface area which helps construct an efficient filler pathway that suppresses the diffusion of a corrosive agent into the polymer matrix. Nevertheless, mechanical properties of the composites are partially improved. Essentially, this study demonstrates that the size of GnP plays a central role in determining the anti-corrosion performance of PU/GnP composites.

Comparison of mechanical reinforcement effects of cellulose nanocrystal, cellulose nanofiber, and microfibrillated cellulose in starch composites

In this work, cellulose nanocrystal (CNC), cellulose nanofiber (CNF), and microfibrillated cellulose (MFC) are used to reinforce starch to obtain high‐performance starch nanocomposites by film casting. The results show that MFC is a highly efficient filler to reinforce starch compared with CNC and CNF. Largely enhanced tensile strength and modulus have been achieved (3.1 MPa, 146.7 MPa for pure starch, 10.6 MPa, 757.4 MPa for starch/MFC composite). Moreover, starch/nanocellulose nanocomposites prepared in this work exhibit excellent transparency and thermostability. Most importantly, the results of sizing performances of the nanocomposites reveal that adding of 3 wt% MFC in starch has obviously enhanced the adhesiveness of sizes to fibers. Our work may help lay a foundation for preparation of high‐performance starch/MFC sizing agents, and contribute to largely expanding the industrial application of CNFs. POLYM. COMPOS., 40:E365–E372, 2019. © 2017 Society of Plastics Engineers

Ultrasound-assisted surface treatment of ZrO2 with BSA and incorporating in PVC to improve the properties of the obtained nanocomposites: Fabrication and characterization

This paper describes the preparation of poly(vinyl chloride) (PVC) nanocomposites (NCs) reinforced with modified zirconia (ZrO2) nanoparticles (NPs). The ZrO2 NPs were defined as efficient filler for PVC NCs. For achieving the best dispersion and improvement of properties, the surface of ZrO2 NPs was modified by Bovine Serum Albumin (BSA). Carboxylic acids and amines are important functional groups of BSA which handle the grafting BSA on the surface of ZrO2 NPs. The PVC/ZrO2-BSA NCs were fabricated by incorporation of various amounts of the ZrO2-BSA NPs (3, 6 and 9wt%) into PVC matrix. All the above processes were accomplished by ultrasonication asa green and environmentally-friendly method. Also, the magnetic and mechanical stirrer was used for the preparation of samples but the results are not suitable and the aggregation was observed which indicated the use of ultrasonic irradiation is the best method for the preparation of NC. The products were characterized by Fourier transform infrared spectroscopy, Transmission electron microscopy, Field emission scanning electron microscopy, X-ray diffraction, Thermogravimetric analysis, Ultraviolet–visible spectroscopy, photoluminescence spectroscopy, energy dispersive X-ray spectroscopy, wettability, and mechanical tests. The achieved PVC/ZrO2-BSA NCs showed high thermal stability, good mechanical, optical and wettability properties compared to the pure PVC. In addition, among the obtained NCs, the PVC/ZrO2-BSA NC 6wt% showed the best improvement.

Employment of ultrasonic irradiation for production of poly(vinyl pyrrolidone)/modified alpha manganese dioxide nanocomposites: Morphology, thermal and optical characterization

This work explains the production, morphology, and features of novel nanocomposite (NC) established on poly(vinyl pyrrolidone) (PVP) as polymer background and modified alpha manganese dioxide (α-MnO2) nanorod (NR) asan efficient filler. At first, one-dimensional α-MnO2 nanorods (NRs) were produced by a hydrothermal technique and then they were amended with stearic acid (SA) by a solvothermal process. In following, the NCs were made by adding different volumes of α-MnO2-SA NR (1, 3 and 5wt%) in the PVP matrix through ultrasonic irradiation as a green, low-cost, fast, and useful technique. Structural and morphological descriptions confirm crystallinity of α-MnO2-SA NRs and showed that NRs have been separately dispersed in PVP matrix with rod-like morphology and diameter of about 40–60nm. The use of modifier and ultrasonic waves is accountable for good homogeneities of NRs. Thermogravimetric analysis revealed that thermal permanency of the obtained NCs has grown with increasing the α-MnO2-SA content. Also, the UV–vis absorption of NCs was enhanced with the incorporation of the modified α-MnO2 NR in PVP matrix. The substantial perfections in NCs properties are associated to compatible intermolecular relations between the surface modifying groups of the α-MnO2-SA and PVP chain.

Mixing process influence on thermal and rheological properties of NBR/SiO2 from rice husk ash

Abstract Silica was extracted from rice husk ash (RHA) by a sequence of reactions to produce nanosilica. Two laboratory routes, co-coagulation and spray drying, were used to incorporate the nanosilica into the rubber matrix. Samples were characterized regarding filler incorporation efficiency, thermal stability, rheological behavior and morphology. Thermogravimetric analysis showed that spray-drying was the most efficient filler incorporation process and also the presence of silica increased the thermal resistance of the rubber compound when compared to the unfilled rubber. The rheological behavior showed that NBR filled with silica presented higher elastic torque (S’), storage modulus (G’) and complex viscosity (η*) than unfilled rubber. The Payne effect was also observed for the composites produced by spray-drying. In addition, the thermal behavior and Payne effect results were supported by the comparison of morphology observed by FEG-SEM analysis.

Layered Tb‐Doped Yttrium Carboxyphosphonate Nanocrystals as Efficient Filler for PEDOT:PSS Composite Films

AbstractA layered yttrium phosphonate based on N‐(phosphonomethyl)glycine (H3L) and of formula Y(PO3CH2NHCH2COOH)(HPO3CH2NHCH2COOH) was synthesized in mild hydrothermal conditions. Its crystal structure was first determined by single‐crystal X‐ray diffraction. Then, the synthetic parameters were changed in order to reduce the particle size of the compound. The use of microwave (MW) irradiation during the synthesis allowed a) to obtain the compound in form of nanoparticles (NP) in the 50–300 nm range dispersed in water, b) to strongly reduce the reaction time by a factor 150, and c) to successfully introduce into the structure small amounts of a luminescent ion like terbium(III) as an isomorphic substituent of yttrium(III). The obtained NP were used to prepare composite materials by dispersing them in poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). The resulting optical, photophysical, morphological and electrical properties of modified and pristine PEDOT:PSS films were investigated and compared, in order to test the potential use of Y(H2L)(HL) NP as luminescent downshifting materials in optoelectronic devices.

Identification of suitable storage materials for solar thermal power plant using selection methodology

Abstract Due to the intermittent nature of solar energy, there is a need to store heat to meet the needs when solar light is not available. Rock bed using air as heat transfer fluid (HTF) is being now used for thermal energy storage (TES) in concentrated solar power (CSP) plants. It is considered as a cost effective storage system. However, no detailed works have been published on selection and identification of rocks for high temperature storage applications. The scope of the present study is to choose the most suitable rocks for high temperature sensible heat storage (SHS) using a methodology based on laboratory measurements. Thus, experimental characterization of several rock types has been performed. An experimental device has been made for thermal conductivity measurement at room temperature. The obtained results show that the gabbro rock is the best candidate material for CSP plants. Comparative study with some other conventional materials found in literature indicates that rock is an efficient filler material for high temperature TES. From the obtained results and correlations, a second selection methodology has been proposed in order to minimize the steps of selection using simple and few tests.

A facile approach to fabricating organosilica layered material with sulfonic groups as an efficient filler for polymer electrolyte nanocomposites

One-pot synthesis of silica layered nanofillers decorated by sulfonic groups and their use for nafion nanocomposites with improved conductivity.

Coating polyrhodanine onto boron nitride nanosheets for thermally conductive elastomer composites

Boron nitride nanosheets (BNNSs) have captured much attention in the fabrication of thermally conductive and electrically insulating polymer-based composites. However, inert surface chemistry of BNNSs largely hampers their applications in polymer composites. Herein, we report a facile approach for the fabrication of elastomer/BNNSs composites with high thermal conductivity. BNNSs were first wrapped by polyrhodanine in water to form the polyrhodanine@BNNSs nanostructure (PRh-BNNSs) and then compounded with styrene-butadiene rubber to form the elastomer composites. Due to the unique curing reactivity of polyrhodanine, strong interfaces were formed in the resulting elastomer composites. Accordingly, the SBR/PRh-BNNSs composites exhibited unique combination of high mechanical properties and high thermal conductivity. Importantly, the orientation of BNNSs in the elastomer led to further increase in thermal conductivity. Overall, the present work offers a new route for the design of thermally conductive elastomers through the combination of efficient interfacial modification and filler organization.

Synergistic effects of hybrid carbon nanomaterials in room‐temperature‐vulcanized silicone rubber

AbstractThis work examines nanocomposites based on nanofillers and room‐temperature‐vulcanized silicone rubber. The carbon nanofillers used were conductive carbon black (CB), carbon nanotubes (CNTs) and graphene (GE). Vulcanizates for CB, GE, CNTs as the only filler and hybrid fillers using CNTs, CB and GE were prepared by solution mixing. The elastic modulus for CNT hybrid with CB at 15 phr (4.65 MPa) was higher than for CB hybrid with GE (3.13 MPa) and CNTs/CB/GE as the only filler. Similarly, the resistance for CNT hybrid with CB at 10 phr (0.41 kΩ) was lower than for CB (0.84 kΩ) at 20 phr and CNTs as the only filler. These improvements result from efficient filler networking, a synergistic effect among the carbon nanomaterials, the high aspect ratio of CNTs and the improved filler dispersion in the rubber matrix. © 2016 Society of Chemical Industry

Prediction of thermal conductivity of composite polymer materials filled with expanded graphite sheet fillers

Adding fillers of high thermal conductivity to the base polymer materials is a solution to make composites of high thermal conductivity. Expanded graphite sheets have been recognized as an economic and efficient filler material to make composite polymers of high conductivity. However, the prediction of the effective thermal conductivity of the composite materials is a difficult task due to the random nature in fillers distribution. The anisotropic properties of the sheet fillers make the heat transfer analysis difficult. In this study, a conjugate heat conduction model considering the random distribution nature of fillers is set up and numerically solved. A validated commercial software FLUENT and finite volume method was used in the analysis. Then an experiment is done to validate the model. The numerical results are used to summarize a correlation for the prediction of the effective thermal conductivity of the composite materials. It is found that the filler height to thickness ratio plays an important role in intensifying the heat conduction in the composite materials. At a given filler content, the graphite sheets should be fabricated thin enough to have higher height to thickness ratios and consequently higher performance in effective conductivity.

Preparation and characterization of poly(vinyl alcohol) biocomposites with microalgae ash

ABSTRACTGasification of microalgae feedstock generates mineral ash. In this work, raw ash is produced from lipid‐extracted algal biomass of the Nannochloropsis salina strain. Prior to using it as filler for composite fabrication with poly(vinyl alcohol), raw ash (RASH) is activated with NaOH and surface modified with (3‐aminopropyl)triethoxysilane. Surface modification of activated ash (PASH) significantly improves interfacial interaction between surface‐modified ash (GASH) and polymer matrix. Higher ultimate tensile strength of PVA/GASH composites is recorded, compared with PVA/RASH and PVA/PASH. Young's modulus of biocomposites appears to increase proportionally to loading of the fillers. Thermal properties of polymeric materials of PVA with these ashes are stable. This is the first report to demonstrate the utilization of microalgal ash, the leftover after completed gasification of algal biomass, as an efficient filler for production of value‐added polymeric materials. It is proposed that microalgal ash is capable of improving the economic feasibility of microalgae‐based biorefinery. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43599.

Comparative studies of radiation-protection fillers for composite materials based on fosfogipsum binder

The results of comparative experimental studies of the effect of various radiation-protection (RP) fillers for composite materials based on phosphogypsum binder on their RP properties were considered. The regularities of the influence of the parameters of X-ray protection structures, such as thickness, RP filler concentration, composite material density and matrix, etc. on the level of radiation protection of personnel taking into account the properties of phosphogypsum-based composite materials were established and, thus, creation technology parameters and efficiency of such structures were substantiated. The high efficiency of the rare earth elements (REE) as RP fillers for the phosphogypsum binder at a concentration of 30% by weight is associated with high RP properties at significantly lower cost compared to other investigated RP fillers. Comparative experimental studies have convincingly shown that REE are technologically advanced and the most efficient RP filler for gypsum binder, which offers the prospect of creating X-ray protection means (including collective) of a new technological level.

Silica-coated nano calcium carbonate reinforced polychloroprene rubber nanocomposites: influence of silica coating on cure, mechanical and thermal properties

The main objective of the present work is to compare the influence of silica-coated nano calcium carbonate (SNCC) with uncoated nano calcium carbonate (NCC) as filler on the property enhancement of polychloroprene rubber (CR) composites. The CR nanocomposites containing SNCC exhibit superior curing, mechanical and thermal properties in comparison to NCC-filled CR nanocomposites. The fantastic enrichment in the resulting properties of CR nanocomposites containing SNCC is mainly due to better rubber–filler interaction resulting from the reasonably excellent dispersion of SNCC within the CR matrix. The more uniform distribution of SNCC in comparison to NCC within the rubber matrix is also confirmed from morphological analysis. Thus, in this article, we report SNCC as a new type of efficient filler to reinforce the ultimate properties of CR nanocomposites for the first time.

A microcosm study of permeable reactive barriers filled with granite powder and compost for the treatment of water contaminated with Cr (VI)

The permeable reactive barrier (PRB) is a technology developed for the removal of contaminants in groundwater. It consists of a screen perpendicular to the flow of contaminated groundwater filled with a material capable of adsorbing, precipitating or degrading pollutants. Several materials have been tested for their use as reactive substrates for the construction of PRBs. Waste materials are of particular interest for this purpose due to the possibility of their reuse and their generally lower cost. With this aim, the Cr (VI) retention capacity of filler material consisting either of pine bark compost (PB) or a 50% mixture of compost and granite powder (PB50) was evaluated using an experimental device specifically designed for this study, which reproduces a permeable reactive barrier at the laboratory scale. Percolation experiments were carried out with a solution of 100 mg L<sup>-1</sup> Cr (VI) in 0.01M KNO<sub>3</sub>, followed by a leaching step with the saline background. The results show that compost is a highly efficient filler for permeable reactive barriers with almost 100% retention of Cr, whereas the retention efficiency of the mixture of PB50 oscillated between 18 and 46% during the experiment. The Cr retained by the filling material is strongly fixed, since no desorption was detected by leaching with the saline background, and concentrations in the standard Toxic Characteristic Leaching Procedure (TCLP) extracts were lower than 1 mg L<sup>-1</sup>. This behaviour minimizes the risk of release of the Cr retained by the material of the barrier in the event of it being traversed by water not contaminated with Cr. Modelling with Visual Minteq indicates that in the experiments with PB, the reduction of Cr (VI) to Cr (III) occurs and that Cr (III) is associated with dissolved organic matter, which is a form of lower toxicity than the initial Cr (VI) species. In turn, in the experiments with PB50, Cr (III) and Cr (VI) coexist and the oxidised form is not associated with dissolved organic matter, which suggests greater toxicity. The results indicate that pine bark compost is a potential candidate for use as filler material permeable reactive barriers.

Organosilane-functionalized halloysite for high performance halloysite/heterophasic ethylene–propylene copolymer nanocomposites

The surface modification of hydrophilic inorganic clays with organosilanes is a promising strategy to improve its dispersion as filler and interaction with hydrophobic polymers. Successful organomodification strongly depends on the characteristics of the silane precursor (functional group, chain size and concentration) and the reaction conditions (solvent polarity). This study correlates these factors with the morphological, thermal and mechanical properties of the final halloysite/heterophasic ethylene–propylene copolymer nanocomposites. When the halloysite (Hal) silane-modification was conducted in nonpolar solvents, the most efficient filler dispersion was achieved. Additionally, a good balance in the mechanical properties was obtained by using the more hydrophobic silane-modifier, improving the Young modulus in 38%, without loss of the impact properties at 23°C. These optimized clay polymer nanocomposites exhibit properties suitable for many industrial applications.

Novel ternary poly(vinyl pyrrolidone)/poly(amide-imide)/ZnO nanocomposite: Synthesis, characterization, thermal and optical performance

Abstract The present work describes the synthesis and properties of polymer composites based on poly(vinyl pyrrolidone) (PVP) as polymer shell and poly(amide-imide)(PAI)/ZnO nanocomposite (ZNC) as efficient filler. At first, the alanine amino acid containing dicarboxylic acid was grafted on the surface of ZnO NPs. Then, modified ZnO (12 wt%) was incorporated into the PAI matrix under ultrasonic irradiations. The obtained hybrid ZNC showed high thermal stability and the size of the NPs in the TEM image of ZNC was about 31 nm. Secondly, PVP NCs with different ZNC loadings such as 2, 4 and 6 wt% were prepared via ultrasonication. Transmission electron microscopy (TEM) observations showed that the ZnO NPs were uniformly and highly dispersed in the PVP matrix. The UV–vis results exposed that the high UV-shielding efficiency of the obtained composites. Thermal analysis represented that the onset decomposition temperatures of the obtained PVPNCs had remarkable increasing in compared to the neat PVP due to the presence of both ZnO NPs and PAI.

Crack Healing in Ti2Al0.5Sn0.5C–Al2O3 Composites

Oxidation induced crack healing of Al2O3 composites loaded with a MAX phase based repair filler (Ti2Al0.5Sn0.5C) was examined. The fracture strength of 20 vol% repair filler loaded composites containing artificial indent cracks recovered fully to the level of the virgin material upon isothermal annealing in air atmosphere after 48 h at 700°C and 0.5 h at 900°C. SEM‐EBSD analysis of crack microstructure indicates two different oxidation reaction regimes to govern the crack filling: near the surface SnO2, TiO2, and Al2O3 were formed whereas deeply inside the cracks Al2O3 and TiO2 and metallic Sn were detected. The presence of elemental Sn was attributed to partial oxidation of aluminum and titanium which lowered the local oxygen concentration below a threshold value required for Sn oxidation to SnO2. Thus, Ti2Al0.5Sn0.5C may represent an efficient repair filler system to trigger oxidation induced crack healing in ceramic composites at temperatures below 1000°C.

Organo-modified layered double hydroxide in coating formulation to protect AA2024 from corrosion

Suggested as efficient filler for impact resistance when dispersed into a coating formulation, layered double hydroxide (LDH) materials organo-modified by aniline and benzene derivatives, 3- and 4-aminobenzensulfonic acid (ABSA) and 3,4-dihydroxybenzoic acid (HHBA), are further investigated here to protect from corrosion aluminium alloy 2024. The concomitant release of interleaved organic molecule as well as the uptake of chloride anion was studied by X-ray diffraction to demonstrate the LDH framework efficiency to act as chloride nanotrap. HHBA was found to be immobilised while the two other molecules are released. DC-polarization experiments demonstrate the efficiency of all three hybrid LDH materials in lowering the corrosion current suggesting that the corrosion inhibition mechanism should either proceed by an anion exchange and/or by a complete dissolution of inorganic framework inducing both the anions release but in the latter case by an additional leaching of the LDH sheet cations. Electrochemical impedance spectroscopy experiments indicate two opposite phenomena: an increase in the barrier properties of the coating in the presence of LDH pigments but as well as in the water uptake process that subsequently causes the protective polymer film to blister. Such delamination allows the electrolyte to migrate but also the corrosion inhibitor agents to flow onto the damaged area. Elemental analyses mapping around damaged area using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy confirm the release of interleaved anticorrosive species that is occurring by anion exchange and/or platelets dissolution when LDH fillers are dispersed into the polymer coating formulation.