Inclusion Of Filler Research Articles

Biocomposites for Orthopedic and Dental Application

The development of polymer and inorganic filler lead to new biocomposite materials with a wide range of applications in orthopedic and dental application. Biomposites possess an excellent biocompatibility, biodegradability and superior mechanical properties. The inclusion of bioactive filler of hydroxyapatite, wollastonite glass-ceramics and bioactive glass could provide bioactivity of biocomposites. This review summarizes the recent work on the development of biocomposites containing biopolymers with different bioactive particles suitable for use in bone defects/bone regeneration and dental application.

Structure and properties of buckypapers based on poly(methyl methacrylate-co-methacrylic acid)/ polyamide 6,6 and carbon nanotube intercalated montmorillonite

Considering the challenge of the tendency of carbon nanotube to aggregate, the originality of fabricating nanocomposites with preformed network through microfiltration of nanotube suspension has been focused. The nanotube may fasten together upon dispersion in a liquid suspension and filtered through a fine mesh forming a thin film known as buckypaper. In this study, initially poly(methyl methacrylate- co-methacrylic acid) (PMMAMA) and polyamide 6,6 (PA-6,6) blend was formed. Later, the matrix was reinforced with carbon nanotube and montmorillonite–modified carbon nanotube (CNT–MMT). In this way, two series of buckypapers, PMMAMA/PA-6,6/CNT 0.5-5 and PMMAMA/PA-6,6/CNT–MMT 0.5-5, were prepared with varying CNT and CNT–MMT content. PA-6,6 was in situ polymerized and the effect of filler inclusion on number and weight average molecular weight was studied. Studies were performed using gel-permeation chromatography, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, thermogravimetric analysis, and cone calorimetry to explore the structure, morphology, thermal, and flammability properties of high-performance composites. PMMAMA/PA-6,6/CNT–MMT revealed CNT–MMT network morphology with triangular porous structure. Thermal stability of PMMAMA/PA-6,6/CNT–MMT 0.5-5 system was found higher than PMMAMA/PA-6,6/CNT 0.5-5. The PHHR of PMMAMA/PA-6,6/CNT–MMT was decreased from 342 to 211 kW/m2 with 0.5 to 5 wt% loading.

Geopolymer: A Review on Physical Properties of Inorganic Aluminosilicate Coating Materials

Geopolymer is a potential material that can be used in many forms of applications such as for building, automotive, aerospace, and many more. It exhibits many excellent physical, thermal and chemical properties. Geopolymer material provides a cost effective and sustainable solution by recycle the hazardous residue material and it undergone green chemistry technique treatment. Geopolymerization process involves combination mixture of aluminosilicate from natural mineral or industrial waste such as fly ash or slag or rice husk ash with activated alkaline solution. This review paper exclusively explore more on the interfacial adhesion of geopolymer coating on substrate surface, effect of coating thickness and filler inclusion in geopolymer matrix system. Literature demonstrates that type of substrate and substrate surface plays a crucial role for good interfacial adhesion with geopolymer materials. In addition, coating thickness will affect the insulating capacity performance, while inclusion of filler can reduce the coating shrinkage problem.

Bio-based polyolefin composites and functional films for reducing total carbon footprint

The utilization of bio-based renewable and sustainable materials for industrial application is pursued aggressively by multiple research entities and manufacturing companies. Effective sequestration of CO2 by sugarcane plantation as a first step, which is then converted to green polyolefin, reduces greenhouse gases effect on global warming. This article addresses bio-based polyethylene composites and functional films for flexible packaging and personal care product applications. The bio-based polyethylene composite films, obtained by melt compounding of thermoplastic cross-linked starch as filler for film casting, show relatively low film modulus, peak stress and total energy to break even at a high level of filler inclusion. In comparison, petroleum-based polyethylene filled with CaCO3 exhibits unusually high film modulus and total energy absorption except for film peak stress. The bio-based polyethylene composite film elongation ranges from 829% for the neat bio-based polyethylene to 522% for the film containing 30% thermoplastic cross-linked starch, whereas petroleum-based polyethylene composite films as a control show relatively small changes in film elongation with and without CaCO3 filler. The scanning electron microscopy results revealed a majority of filler is in micrometer sizes in the bio-based PE composite films and an open porous network existed for breathable films containing CaCO3 as filler.

Fluoride release, recharge and flexural properties of polymethylmethacrylate containing fluoridated glass fillers.

The purpose of this study was to investigate the effect of fluoridated glass fillers on fluoride release, recharge and the flexural properties of modified polymethylmethacrylate (PMMA). Specimens of PMMA denture base material with various loading of fluoridated glass fillers (0%, 1%, 2.5%, 5% and 10% by weight) were prepared. Flexural properties were evaluated on rectangular specimens (n=10) aged in deionized water after 24hours, 1 and 3months. Disc specimens (n=10) were aged for 43days in deionized water and lactic acid (pH 4.0) and fluoride release was measured at numerous intervals. After ageing, specimens were recharged and fluoride re-release was recorded at 1, 3 and 7days after recharge. Samples containing 2.5%, 5% and 10% glass fillers showed significantly (p<0.05) greater levels of fluoride release compared with the control and 1% glass fillers specimens. All experimental specimens exhibited fluoride release in both media. The flexural strength of specimens decreased in proportion to the percentage filler inclusion with the modulus of elasticity values remaining within ISO Standard 1567. The modified PMMA with fluoridated glass fillers has the ability to release and re-release fluoride ion. Flexural strength decreased as glass filler uploading increased.

Impacted dentures in the oesophagus.

This study presents the incidence of denture impaction in the oesophagus, and discusses the difficulties of managing such cases. A total of 262 patients with a history of foreign body ingestion (between 1999 and 2010) were reviewed; 46 of these patients had dentures impacted in the oesophagus. The cervical section of the oesophagus was the commonest site of impaction. Dysphagia and tracheal tenderness were the most consistent features when dentures became impacted in the upper oesophagus. In most cases, rigid oesophagoscopy enabled successful removal of the impacted denture. Locating an impacted denture hidden within the oesophageal mucosal folds sometimes proved difficult. In cases of impacted dentures in the oesophagus, a positive history helps in the diagnosis, but a high degree of clinical suspicion aids early detection. Conventional radiographs are important but may not always be of assistance. Early intervention reduces complications. Dentures that are poorly maintained and old are more likely to be swallowed accidentally. The inclusion of radiopaque filler within dentures would assist localisation following accidental swallowing.

Capacitive behavior studies on electrical double layer capacitor using poly (vinyl alcohol)–lithium perchlorate based polymer electrolyte incorporated with TiO2

Electric double layer capacitors (EDLCs) based on activated carbon electrodes and poly (vinyl alcohol)–lithium perchlorate (PVA–LiClO4)-nanosized titania (TiO2) doped polymer electrolyte have been fabricated. Incorporation of TiO2 into PVA–LiClO4 system increases the ionic conductivity. The highest ionic conductivity of 1.3 × 10−4 S cm−1 is achieved at ambient temperature upon inclusion of 8 wt.% of TiO2. Differential scanning calorimetry (DSC) analyses reveal that addition of TiO2 into polymer system increases the flexibility of polymer chain and favors the ion migration. Scanning electron microscopy (SEM) analyses display the surface morphology of the nanocomposite polymer electrolytes. The electrochemical stability window of composite polymer electrolyte is in the range of −2.3 V to 2.3 V as shown in cyclic voltammetry (CV) studies. The performance of EDLC is evaluated by electrochemical impedance spectroscopy (EIS), CV and galvanostatic charge–discharge technique. CV test discloses a nearly rectangular shape, which signifies the capacitive behavior of an ELDC. The EDLC containing composite polymer electrolyte gives higher specific capacitance value of 12.5 F g−1 compared to non-composite polymer electrolyte with capacitance value of 3.0 F g−1 in charge–discharge technique. The obtained specific capacitance of EDLC is in good agreement with each method used in this present work. Inclusion of filler into the polymer electrolyte enhances the electrochemical stability of EDLC.

Investigations on Mechanical and Tribological Behaviour of Particulate Filled Glass Fabric Reinforced Epoxy Composites

The aim of the research article is to study the mechanical and two-body abrasive wear behaviour of alumina (Al2O3) filled glass fabric reinforced epoxy (G-E) composites. Alumina filled G-E composites containing 0, 5, 7.5 and 10 wt% were prepared using the hand lay-up technique followed by compression molding. The mechanical properties such as tensile strength, hardness and tensile modulus were investigated in accordance with ASTM standards. Two-body abrasive wear studies were carried out using a pin-on-disc wear tester under multi-pass condition against the water proof silicon carbide abrasive paper. From the experimental investigation, it was found that the presence of Al2O3 filler improved the tensile strength and tensile modulus of the G-E composite. Inclusion of Al2O3 filler reduced the specific wear rate of G-E composite. The results show that in abrasion mode, as the filler loading increases the wear volume decreases and increased with increasing abrading distance. The excellent wear resistance was obtained for Al2O3 filled G-E composites. Furthermore, 10 wt% filler loading gave a very less wear loss. Finally, the scanning electron microscopic observations on the wear mechanisms Al2O3 filled G-E composites was discussed.

Taguchi approach for characterization of three-body abrasive wear of carbon-epoxy composite with and without SiC filler

Fiber–matrix interfacial bonding plays a critical role in controlling performance properties of polymer composites. Carbon fibers have major constraints of chemical inertness with the matrix and need the surface treatment to improve the adhesion with the matrix. In this work, parametric appraisal of three-body abrasive wear behavior was presented for silane treated carbon fabric reinforced epoxy (C-E) composites with and without silane treated silicon carbide (SiC) as filler. The fiber content was fixed at 60 wt.%, while the weight fraction of SiC was varied (5 and 10 wt.%) to obtain three different compositions. Three-body abrasive wear tests were conducted using design of experiments approach based on Taguchi’s orthogonal arrays. The findings of experiments indicate that the wear loss is greatly influenced by load and grain size of abrasive. An optimal parameter combination was determined, which leads to maximization of abrasion resistance. Inclusion of SiC filler reasonably increased the abrasion resistance of C-E composite. Analysis of variance results showed that the load significantly influenced the abrasion of SiC filled C-E composites. Efforts were also made to correlate the abrasive wear performance of SiC filled C-E composites using artificial neural network (ANN). The wear behavior of composite by ANN prediction closely matched the experimental results and finally, optimal wear settings for minimum wear were identified.

Influence of Titanium Carbide on the Three- Body Abrasive Wear Behaviour of Glass-Fabric Reinforced Epoxy Composites

The three-body abrasive wear of Titanium Carbide (TiC) filled and unfilled E-glass-epoxy (G-E) was experimentally investigated using rubber wheel abrasion tester (RWAT). The composites were fabricated by using vacuum assisted resin transfer molding (VARTM) with 0-6 wt % of TiC in steps of 2 wt %. The mechanical properties of the TiC filled and unfilled glass fabric reinforced epoxy (G-E) composites have been evaluated. From the experimental results, it is observed that the mechanical properties of the G-E composite are better with the inclusion of TiC filler. The effect of abrading distance, viz., 150, 300, 450 and 600 m and two different loads of 22 and 32N at 200 rpm have been studied. Angular grained silica sand particles of size 200–250 µm were used as dry and loose abrasives. The inclusion of TiC filler in the epoxy lead to a significant influence on abrasive wear resistance of G-E composites. The volume loss of the composite has been determined and it increases with the increasing abrading distance. The morphologies of the worn surface of the composites were analyzed to understand the wear mechanisms by means of scanning electron microscopy (SEM).

Development of epoxy/BN composites with high thermal conductivity and sufficient dielectric breakdown strength part II-breakdown strength

The aim of this research is to find a way to achieve the epoxy composites with high thermal conductivity and acceptable dielectric breakdown (BD) strength. A value 12.3 W/m·K is the highest thermal conductivity obtained for epoxy composite in Part I. Dielectric breakdown performances such as short-time dielectric breakdown strength (BD strength), partial discharge (PD) resistance and BD time for composites were investigated in the Part II. In general, micro filler inclusion will increase thermal conductivity and decrease dielectric breakdown performance. Influencing factors are considered to be the orientation of filler, the content of void space, the content ratio in the case of co-mixing, the addition of nano filler, and filler surface modification. Twenty six kinds of composites were prepared in consideration of the above influencing factors. There are two options for most appropriate ones among the composites evaluated in the research. One is an epoxy/ conglomerated h-BN composite with co-loaded nano SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> and micro AIN filler. It has 12.3 W/m·K in thermal conductivity, 75.1 kV <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">peak</sub> /mm in BD strength and 260 % of BD time for neat epoxy. It is most suitable when low BD strength and high thermal conductivity is needed. The other one is an epoxy/ h-BN composite with co-loaded nano silica and AIN filler for requirement of very high BD strength but lower thermal conductivity. Optimum thermal conductivity is obtained if flaky h-BN filler is oriented in parallel to heat flow. Since it is difficult to realize full orientation, the use of conglomerated h-BN filler is a suitable option. Optimum BD performance is obtained if void space is reduced by certain methods such as co-dispersion of different size fillers and addition of nano filler.

Assessment of the effect of mineral filler on asphalt–aggregate interfaces based on thermodynamic properties

The material properties of hot mix asphalt (HMA) are modified by the amount and properties of the mineral filler (or filler) incorporated in the HMA. This paper focuses on the analysis of the filler effect on asphalt–aggregate interfaces of HMA based on thermodynamic properties (i.e., measurements of surface free energy, SFE, performed on asphalts, mastics (asphalt–filler combinations), and aggregates). Seven asphalts, three different mineral fillers added at different proportions, and six aggregates were assessed. The analysis was conducted in terms of energy parameters computed by using the SFE components of the materials evaluated. Corresponding results suggest that the inclusion of filler in the asphalt led to changes in the resistance to both fracture and moisture damage of the mastic–aggregate systems, and the wettability of the mastic over the aggregate as evaluated in terms of the energy parameters. Since these particular effects are not comprehensively captured based on conventional tests currently used for filler characterization—which mainly evaluate particle size, presence of harmful fines, and morphological properties, the HMA mix design can benefit from characterization of fillers and mastics in terms of the SFE and subsequent computation of the energy parameters included in this study.

4-META系ボンディング材/TMPTフィラー含有コンポジットレジンと象牙質・歯髄複合体の反応

4-META系ボンディング材/TMPTフィラー含有コンポジットレジンと象牙質・歯髄複合体の反応

Effect of Mineral Filler Characteristics on Asphalt Mastic and Mixture Rutting Potential

This study, part of the NCHRP 9–45 Project, analyzed the effect of mineral filler properties on asphalt mastic and the rutting potential of asphaltic mixture. The mineral filler properties were characterized by four tests: Rigden voids (RV), fineness modulus (FM), calcium oxide (CaO) content, and methylene blue value. The rheological properties of asphalt binder and mastic were characterized with the use of apparent viscosity and multiple stress creep recovery tests. Dynamic modulus and flow number tests were conducted to examine the asphaltic mixture rutting potential. The tested mixtures included several variables: four asphalt binder types, including virgin and polymer modified; two aggregate gradations; and a selected group of fillers. The study concluded that asphalt mastic performance was significantly affected by the fractional voids in the filler and possibly by the CaO content and FM. This effect, however, depended on binder type. On the one hand, the styrene–butadiene–styrene modified binder showed the strongest effect as a result of the mineral filler inclusion when tested as mastic. On the other hand, RV and CaO content showed relatively greater correlation with the mixture rutting potential, as compared with other filler properties. Addition of RV improved the prediction models for dynamic modulus and flow number. The effect of RV on the mixture rutting potential was more pronounced for the coarse mixture than for the fine mixture.

Structural, elastic and thermal properties of titanium dioxide filled isotactic polypropylene

Titanium dioxide (TiO2)-filled isotactic polypropylene (iPP) composites with various contents of TiO2 were prepared by a locally fabricated extrusion molding machine. The extrudates were melt-pressed at 180 °C and produced as plane sheets of nearly equal thickness by rapid cooling. X-ray diffraction studies reveal a decrease of crystallinity and crystallites size as well as a change of α-, β- and γ-crystalline phases of the neat iPP to the α-form due to filler inclusion. Scanning electron micrographs taken on the fractured surface of the samples show increasing amount of voids with increasing filler content. Tensile strength, elongation-at-break (%) and glass transition temperature of the samples are found to decrease considerably with the increase in TiO2 content, whereas microhardness decreases slightly with the filler content.

A new technique for firn grain-size measurement using SEM image analysis

AbstractFirn microstructure is accurately characterized using images obtained from scanning electron microscopy (SEM). Visibly etched grain boundaries within images are used to create a skeleton outline of the microstructure. A pixel-counting utility is applied to the outline to determine grain area. Firn grain sizes calculated using the technique described here are compared to those calculated using the techniques of Gow (1969) and Gay and Weiss (1999) on samples of the same material, and are found to be substantially smaller. The differences in grain size between the techniques are attributed to sampling deficiencies (e.g. the inclusion of pore filler in the grain area) in earlier methods. The new technique offers the advantages of greater accuracy and the ability to determine individual components of the microstructure (grain and pore), which have important applications in ice-core analyses. The new method is validated by calculating activation energies of grain boundary diffusion using predicted values based on the ratio of grain-size measurements between the new and existing techniques. The resulting activation energy falls within the range of values previously reported for firn/ice.

Structures and Performance of White Clay-Filled Isotactic-Polypropylene Composites Prepared by Double-Molding Techniques

Various contents of Bangladeshi white clay (WC)-filled Isotactic polypropylene (iPP) composites were fabricated by double-molding techniques. Scanning electron micrographs shows a good impact between iPP matrix and fillers. X-diffraction and IR spectroscopic measurements reveal that inclusion of fillers develops an additional γ-crystal along with the α- and β-crystals that are merely observed in the neat iPP. Young's modulus and microhardness are found to increase with increasing WC content. Thermal analyses represent a considerable increase of thermal stability of the composites with filler addition. Appearance of new crystalline phase by filler inclusion and performances of the composites are discussed in detail.

Influence of graphite filler on two-body abrasive wear behaviour of carbon fabric reinforced epoxy composites

The influence of graphite filler additions on two-body abrasive wear behaviour of compression moulded carbon–epoxy (C–E) composites have been evaluated using reciprocating wear unit and pin-on-disc wear unit under single pass and multi-pass conditions respectively. The carbon fabric used in the present study is a plain one; each warp fiber pass alternately under and over each weft fiber. The fabric is symmetrical, with good stability and reasonable porosity. Abrasive wear studies were carried out under different loads/abrading distance using different grades of SiC abrasive paper (150 and 320 grit size). Graphite filler in C–E reduced the specific wear rate. Further, the wear volume loss drops significantly with increase in graphite content. Comparative wear performance of all the composites showed higher specific wear rate in two-body wear (single-pass conditions) compared to multi-pass conditions. Further, the tribo-performance of C–E indicated that the graphite filler inclusion resulted in enhancement of wear behaviour significantly. Wear mechanisms were suggested and strongly supported by worn surface morphology using scanning electron microscopy.

Elasticity Determination of Adhesive Patches With Filler Inclusion

Patches can be used for topical and transdermal drug delivery as well as for cosmetic purposes. Their mechanical properties (i.e. strength, brittleness, elasticity, etc.) are important features that can influence their therapeutic success. Most of the drug-in-adhesive (DIA) patches adhere well to the skin or other surfaces. However, their degree of elasticity cannot be accurately determined since during the compression–decompression cycle(s), the patches adhere to the moving plate (and sensor), resulting in under the x-axis forces (and “negative” areas in the stress–strain curves). We overcame this limitation using two different approaches: gluing thin non-adhesive plates to both sides of the patch or applying talc granules to both surfaces. These treatments rendered the patch surfaces non-adhesive, thereby eliminating the “negative” force (and area) and permitting testing of adhesive materials as well as determination of their degree of elasticity. The general level of calculated recoverable work was ∼60–80% of the total work for the patches, i.e., they can be considered elastic entities. When the strain rate was 100 mm/s, the calculated recoverable work “jumped” to ∼92% and changed in a significant manner. Inclusion of fillers (corn or potato starch) in the patch reduced the percent recoverable work and degree of elasticity. For the first compression–decompression cycle, there was an increase in the degree of elasticity of the compressed–decompressed patches; while in the third and fourth cycles, there were no statistical differences in the extents of percent recoverable work. Recoverable work vs cycle number was almost a mirror image of total work.

Influence of silicon carbide filler on mechanical and dielectric properties of glass fabric reinforced epoxy composites

AbstractFiber‐reinforced polymeric composites (FRPCs) have emerged as an important material for automotive, aerospace, and other engineering applications because of their light weight, design flexibility, ease of manufacturing, and improved mechanical performance. In this study, glass‐epoxy (G‐E) and silicon carbide filled glass‐epoxy (SiC‐G‐E) composite systems have been fabricated using hand lay‐up technique. The mechanical properties such as tensile strength, tensile modulus, elongation at break, flexural strength, and hardness have been investigated in accordance with ASTM standards. From the experimental investigations, it has been found that the tensile strength, flexural strength, and hardness of the glass reinforced epoxy composite increased with the inclusion of SiC filler. The results of the SiC (5 wt %)‐G‐E composite showed higher mechanical properties compared to G‐E system. The dielectric properties such as dielectric constant (permittivity), tan delta, dielectric loss, and AC conductivity of these composites have been evaluated. A drastic reduction in dielectric constant after incorporation of conducting SiC filler into epoxy composite has been observed. Scanning electron microscopy (SEM) photomicrographs of the fractured samples revealed various aspects of the fractured surfaces. The failure modes of the tensile fractured surfaces have also been reported. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009