Chemical Composition Of Filler Research Articles

Effect of Laser Welding Parameters with Different Fillers on Solidification Cracking and Mechanical Properties of AA7075

AA7075 is considered a ‘non-weldable’ alloy using fusion welding methods. In this study, laser welding is applied in pulse mode to weld 2 mm thick AA7075 aluminum alloy plates using different fillers. The aim is to identify the influence of welding parameters and fillers on solidification cracking susceptibility during laser welding using the circular patch test (CPT). X-ray radiography was used to detect and measure cracks in the CPT samples. Furthermore, the effects of the laser welding process and chemical composition of fillers on the accumulated crack length (CCL), microstructure, and mechanical properties were investigated. Moreover, the mechanical behavior and local deformation of the fusion zone (FZ) were investigated using micro-flat tensile tests with digital image correlation. The mechanical properties of the FZ were correlated with the CCL as well as with the microstructure of the FZ, which was investigated experimentally. The results show that the chemical composition of fillers and welding speed affect the CCL of solidification cracks. Changes in the microstructure were observed within the fusion zone, and the structure became uniform and finer with the formation of Mg2Si and magnesium-rich, copper, and zinc (η-phase) particles.

Biocomposites of Low-Density Polyethylene Plus Wood Flour or Flax Straw: Biodegradation Kinetics across Three Environments.

The purpose of this study was to assess the potential for biocomposite films to biodegrade in diverse climatic environments. Biocomposite films based on polyethylene and 30 wt.% of two lignocellulosic fillers (wood flour or flax straw) of different size fractions were prepared and studied. The developed composite films were characterized by satisfactory mechanical properties that allows the use of these materials for various applications. The biodegradability was evaluated in soil across three environments: laboratory conditions, an open field in Russia, and an open field in Costa Rica. All the samples lost weight and tensile strength during biodegradation tests, which was associated with the physicochemical degradation of both the natural filler and the polymer matrix. The spectral density of the band at 1463 cm−1 related to CH2-groups in polyethylene chains decreased in the process of soil burial, which is evidence of polymer chain breakage with formation of CH3 end groups. The degradation rate of most biocomposites after 20 months of the soil assays was greatest in Costa Rica (20.8–30.9%), followed by laboratory conditions (16.0–23.3%), and lowest in Russia (13.2–22.0%). The biocomposites with flax straw were more prone to biodegradation than those with wood flour, which can be explained by the chemical composition of fillers and the shape of filler particles. As the size fraction of filler particles increased, the biodegradation rate increased. Large particles had higher bioavailability than small spherical ones, encapsulated by a polymer. The prepared biocomposites have potential as an ecofriendly replacement for traditional polyolefins, especially in warmer climates.

By-Products from Food Industry as a Promising Alternative for the Conventional Fillers for Wood-Polymer Composites.

The present paper describes the application of two types of food-industry by-products, brewers’ spent grain (BSG), and coffee silverskin (ŁK) as promising alternatives for the conventional beech wood flour (WF) for wood–polymer composites. The main goal was to investigate the impact of partial and complete WF substitution by BSG and ŁK on the processing, structure, physicochemical, mechanical, and thermal properties of resulting composites. Such modifications enabled significant enhancement of the melt flowability, which could noticeably increase the processing throughput. Replacement of WF with BSG and ŁK improved the ductility of composites, which affected their strength however. Such an effect was attributed to the differences in chemical composition of fillers, particularly the presence of proteins and lipids, which acted as plasticizers. Composites containing food-industry by-products were also characterized by the lower thermal stability compared to conventional WF. Nevertheless, the onset of decomposition exceeding 215 °C guarantees a safe processing window for polyethylene-based materials.

Crystallization of precisely halogen-substituted polyethylenes induced by ultra-high molecular weight polyethylene fiber

The precisely halogen-substituted polyethylenes prepared by ADMET polymerization, that is, PE21F, PE21Cl and PE21Br were chosen as substituted polymers model to study the epitaxial crystallization of substituted polymers induced by the UHMWPE fiber. The morphology, structure and melting behavior of the crystals were characterized by SEM, WAXD and DSC, respectively. The results showed that ribbon crystals with molecular chains parallel to the fiber axis formed on the UHMWPE fiber surface, and the size and regularity decreased with the increase of substituent volume. PE21F with a small substituent could be induced to form two-component crystals on the UHMWPE fiber surface. However, when the substituent volume increased to Cl and Br, the order of crystal formed on the fiber surface was relatively low, which could not induce the crystallization of peripheral molecules. The melting temperatures of the crystals formed on fiber were much higher than that of the bulk polymers, which was attributed to more ordered crystal structure and the thicker lamellae induced by the UHMWPE fiber. In addition, we also discussed the influence mechanism of different structural characteristics and chemical composition of fillers on the crystallization behavior of substituted polymers. This study will establish a better understanding of interface-induced crystallization.

Eco-Friendly Composites Derived from Natural Rubber and Wasted Materials

The fillers from agriculture and industrial wastes filled natural rubber (NR) have been prepared to clarify their properties and develop to be the eco-friendly composites. This research aims to study the composites namely rice husk ash (RHA)/NR, clay/NR and crumb rubber/NR composites on the curing characteristics, mechanical and morphological properties. The results indicated that depending on a chemical composition of fillers, the properties of the composites are varied. For clay/NR composite, the occurrence of vulcanization was delayed comparing to the others. In term of mechanical properties, crumb/NR composite shows a toughest characteristic, for examples, it has the highest tensile strength, elongation at break and tear resistance, whereas hysteresis loss was found to be lowest among the composites. The toughness of crumb/NR composite can be influenced by a better interfacial interaction between filler and matrix comparing to the others as revealed by SEM. The clay/NR composite, on the other hand, has the highest hardness among the composites due to the hardness of clay itself and its uniformity of particle size. In the case of RHA/NR composite, from morphological observation by SEM shows that RHA particles have very poor dispersion in NR matrix which resulted in poor mechanical properties. However, the presence of RHA agglomerates was found to be beneficial for loading a high stress under a small deformation, for example, at 25% elongation. Therefore, these three difference composites from wasted materials were found to have unique characteristics which can be chosen and applied for some specific applications.

Fire-Resisting Composites Based on Polymer Matrix

In the present work we have studied the thermal stability, flammability, fume evolution of epoxy matrix composites with different types and amounts of hardeners, fillers, plasticizers and fire retardants. It is shown that chemical composition of fillers has little effect on the flammability of epoxy composites when the content of mineral fillers is less than 45% by mass. Smoke formation decreases linearly with increasing the degree of filling. It is shown that to obtain low-combustible materials the oxygen index should exceed 31%. It was found that the optimal concentration of industrial brominated fire retardants is 8-10% by mass. To reduce the flammability of epoxy composites, additive brominated fire retardants in the form of a solution in N,N-dimethyl-2,4,6-tribromoaniline have been proposed. The high efficiency of acetyl-and α-hydroxyethyl ferrocene as a smoke suppressor of epoxy composites is shown.

Fire-Resiting Composites Based on Polymer Matrix

In the present work we have studied the thermal stability, flammability, fume evolution of epoxy matrix composites with different types and amounts of hardeners, fillers, plasticizers and fire retardants. It is shown that chemical composition of fillers has little effect on the flammability of epoxy composites when the content of mineral fillers is less than 45% by mass. Smoke formation decreases linearly with increasing the degree of filling. It is shown that to obtain low-combustible materials the oxygen index should exceed 31%. It was found that the optimal concentration of industrial brominated fire retardants is 8-10% by mass. To reduce the flammability of epoxy composites, additive brominated fire retardants in the form of a solution in N,N-dimethyl-2,4,6-tribromoaniline have been proposed. The high efficiency of acetyl-and α-hydroxyethyl ferrocene as a smoke suppressor of epoxy composites is shown.

Effect of various filler types on the properties of porous asphalt mixture

The open structure of porous asphalt exposes a large surface area to the effects of air and water, which accelerates the oxidation rate and affects the coating properties of the binder. These factors may influence the adhesive strength of the binder-aggregate and lead to cohesive failure within the binder film, contributing to aggregate stripping and moisture damage. The addition of fillers in asphalt mixtures has been identified to stiffen the asphalt binder and improve mixture strength. This study investigates the effect of various filler types (hydrated lime, cement, and diatomite) on the properties of porous asphalt. Compacted samples of porous asphalt were prepared using Superpave gyratory compactor at the target air void content of 21%. Each sample was incorporated with 2% of filler and polymer-modified binder of PG76. The morphology and chemical composition of fillers were investigated with a field emission scanning electron microscope (FESEM) and energy dispersive X-ray (EDX) analysis. The properties of porous asphalt were evaluated in terms of permeability, abrasion loss, resilient modulus, and indirect tensile strength. All mixtures were found to show high permeability rates. Mixtures with hydrated lime exhibited lower abrasion loss compared to mixtures with cement and diatomite. The use of diatomite increases the resistance of the mixtures to rutting and moisture damage compared to other fillers as shown by the enhanced resilient modulus and indirect tensile strength.

Pemanfaatan limbah piston bekas sebagai filler metal aluminium pada pengelasan oxy-acetylene

The abundance of waste piston used so far has not been utilized properly. Users of this piston waste can be used as an oxy-acetylene welder filler. Las oxy-acetylene has been widely used for welding on various types of aluminum product repair, one of which is welding machine block. Machine blocks in their use often suffered damage to the cooling water circulation path and broken crack and broken. Welders and repair shops that repair these damages do not have standardized standards in the use of weld fillers, but they do filler selection based solely on experience including in determining the weld filler. The purpose of this research is to know the effect of piston waste which is used as raw material of weld filler to tensile strength and hardness of welded block result of machine using oxy-acetylene welding. Welding is done by an experienced welder. The welding results are tested for tensile strength and hardness distribution test. The welded joint with the chemical composition of filler which is almost equal to base metal has the highest tensile strength. The tensile strength of the welded joint tension test is in the weld metal region due to defects in the weld metal, especially the porosity defects that are formed during the welding process so that the tensile test loading is concentrated on the defect. While the highest hardness on the weld is in the filler metal with the highest percentage of Si content.

Optimalisasi Komposisi Kandungan MN Pada Filler untuk Mendapatkan Ketangguhan dan Kekerasan

Submerged Arc Welding (SAW) is a welding process used for fabrication of pipes, for example spiral welded pipes. The technique can be operated automatically and has a high reliability in many various welding applications. Some factors affecting the strength of weld metals are heat input, current, and chemical composition of filler, flux, and base metal. The present investigation aims to study microstructure-hardness relationship of submerged arc spiral welded steel pipes. Material used in this experiment was API 5L X-52 and API 5L X-60 for spiral welded steel pipes. Welding was carried out using voltage of 35 volt, welding speed of 13,67 mm/s whereas composition Mn on the flux was varied, 1.7; 1.4; 1.4 with Mo and 1.09. Microstructure and hardness were conducted on base metal, weld metal and heat affected zone (HAZ). Results show that, an increase in composition of Mn could be increases the amount of acicular ferrite structure in weld metal. The hardness and thougness number is increase correlated with increase number of Mn, but for the composition Mn as 1,7, the number of acicular ferrite is decrease, the consequence of hardness number is decrease.

In vitro contact wear of dental composites

Objective. The aim of this study is to determine the in vitro two-body contact wear mechanisms of three medium filled composites and compare these with a highly filled composite previously investigated. Materials and methods. Three commercial dental composites with filler mass fraction loading of 75–76% were evaluated. Two of the composites contained Ba–B–Al-silicate glass fillers and fumed silica with different particle sizes and distributions. One of these composites contained a fairly uniform distribution of filler particles ranging in size from 1 to 5 μm, whereas the particle size distribution in the second composite was bimodal consisting of small (less than 1 μm) and large (about 10 μm) particles. The third composite contained Ba–Al-silicate glass and silica with a filler particle size of approximately 1 μm. The composite disks were tested for wear against harder alumina counterfaces. Wear tests were conducted in distilled water using a pin-on-disk tribometer under conditions that represented typical oral conditions (sliding speed of 2.5 mm/s and contact loads ranging from 1 to 20 N). The wear tracks were analyzed by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy to elucidate the wear mechanisms. The chemical composition of the water solution collected after the tests was determined using an inductively coupled plasma-mass spectrometer (ICP-MS) to detect possible chemical changes, e.g. dissolution of trace elements due to submersion or wear. The wear results were compared with those reported in an earlier study on a highly filled composite containing predominately alumino-silicate glass fillers and alumina at a filler loading of 92%. Results. The differences in two-body wear rates between the three medium filled composites were not statistically significant ( p<0.05) indicating that the variations in filler particle size and slight differences in chemical composition of the glass fillers do not affect the in vitro wear rates of these composites. Wear rates of these medium filled composites, however, were significantly lower than the highly filled composite ( p<0.05). SEM, FTIR and ICP-MS analyses suggested that wear in the medium filled composites occurs by a complex set of processes involving tribochemical reactions between filler particles and water, formation of surface films containing a mixture of filler fragments and reaction products, and film delamination, as well as dissolution of the reaction products. Significance. This study reveals that subtle changes in the filler particle size and small differences in filler composition do not significantly affect the two-body wear behavior of medium filled composites. However, the chemistry of filler particles plays an important role in altering the wear performance of composites when significant changes are made in the chemical composition of the fillers and when the filler loading is increased.