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NdFeB magnetic alloy is one of the hard magnets having the highest maximum energy in the world. The most popular methods of manufacturing magnetic alloys Nd2Fe14B are powder metallurgy and rapid quenching techniques. In this research, the effect of the hot press temperature on the magnetic properties of the hard magnet Nd2Fe14B was studied. Structural studies were carried out using X-ray diffraction, X-ray fluorescence spectrometer and Scanning Electron Microscope; Spectroscopic energy distribution of Nd2Fe14B bulk magnet and the magnetic tests were done using a vibrating magnetometer to investigate the structures and the magnetic properties of the produced samples. The results showed that in addition to the Nd2Fe14B phase, the α-Fe and Nd-rich phase also existed in the structure of the provided magnet. These secondary phases had effectively created exchange couplings with the main phase, improving the magnetic properties. The magnetic properties of the sintered magnets were improved by increasing the press temperature; finally, Nd2Fe14B magnet was made with the maximum energy, which was d higher than 290 kj/m3 .

In this study, the reduction in the hot press time using high thermally conductive fillers and the influenceof these fillers on physical and mechanical properties of end products was investigated. Variable factors in these treatments were type and content of fillers. Press time and other factors such as the amount of wood flour, board density, and other conditions of press were fixed. Composites were prepared from Beech (Fagus orientalis) flour, Polypropylene, MAPP, and conductive fillers such as flake and powder graphite (carbonic fillers), and Alumina (ceramic filler). Fillers with contents of 5 and 10% in 15 and 20 minutes for press time were utilized. A thermocouple was utilized to measure the temperature in the core of composite and to determine the time being panel core as the same temperature as the hot press surface. It showed that fillers reduce press time as 2-4 minutes. Mechanical tests including tension, bending, impact and hardness were performed. Fillers except of flake graphite had no restriction in mechanical properties. Water uptake and swelling as physical properties were also measured and fillers didn’t have a significant effect on these tests. To validate the experimental results, thermal conductivity of composites was determined and the increase in this property was evaluated. The increase in samples contain flake and powder graphite was more remarkable than those contain Alumina.

For this study 10 logs of Paullowina.furtunie from Shastkalateh forest of Gorgan in Iran were selected randomly. After that, 45 clear flat swan specimens prepared and dried to 5% moisture. Density of each log and thickness of specimens were measured. Three levels of compression percent (16%, 33% and 50%) and temperature (130°C, 145°C and 160°C) were the variables. The physical properties of specimens such as spring back, compression set and thickness swelling were calculated. Also, MOE, MOR and impact resistance of specimens were evaluated. In order to have accurate examination, microscopic images were taken. Results show that, with increasing in compression percent, the amounts of spring back and thickness swelling enhance. Densification with 16% compression, yields deformation in elastic region while 33% and 50% compression, causes more compression set. The more compression percent, the more mechanical strengths and the highest strength attained in 50% compression. The effect of temperature was insignificant mostly. Finally, the proper treatment for Paullownia densification, was 130°C and 50% compression. Microscopic images asserted the above results and illustrated that, the enhancing of densification above 50% compression is possible.

NdFeB magnetic alloy is one of the hard magnets having the highest maximum energy in the world. The most popular methods of manufacturing magnetic alloys Nd2Fe14B are powder metallurgy and rapid quenching techniques. In this research, the effect of the hot press temperature on the magnetic properties of the hard magnet Nd2Fe14B was studied. Structural studies were carried out using X-ray diffraction, X-ray fluorescence spectrometer and Scanning Electron Microscope; Spectroscopic energy distribution of Nd2Fe14B bulk magnet and the magnetic tests were done using a vibrating magnetometer to investigate the structures and the magnetic properties of the produced samples. The results showed that in addition to the IFeyB phase, the a-Fe and Nd-rich phase also existed in the structure of the provided These secondary phases had effectively created exchange couplings with the main phase, improving the magnetic properties. The magnetic properties of the sintered magnets were improved by increasing the press temperature; finally, Nd2Fe14B magnet was made with the maximum energy, which was d higher than 290 kj/m3. [ABSTRACT FROM AUTHOR]

In this study, effect of nano-wollastonite on fire resistance characteristics of wood flour/polypropylene composite was investigated. The composites samples were manufactured using a dry blend/hot press method. In this study, the dried wood flour of beech as the filler in a 60%, poly propylene as the matrix in a 37% and polyethylene grafted with maleic anhydride as the coupling agent in a 3% total weight was used. Also, nano-wollastonite was used in four levels of dried wood flour loading (0, 1, 3 and 5%). Nominal density and dimensions of the composites were 1 g/cm3 and 1*20*25 cm, respectively.Bending strenght according to ASTM standard and Fire resistance characteristics such as, flammability duration, duration of flame after removing the burner, duration of glow after removing the burner and mass reduction were measured acceding to ISO 11925. Results indicated that by increasing the nano-wollastonite increases the bending strengh,MOE and flammability duration increased but mass reduction, duration of flame and duration of glow decreased. Also the dispersion of nano-wollastonite in composites was evaluated by Filed Emission Scanning Electron Microscopy (FE-SEM).

In this study the effect of white and brown-rot fungi on durability and hardness characteristics of Bagasse/Polypropylene composite was evaluated. The test specimens were prepared using Bagasse fibers (38%), Polypropylene (60%), and maleic anhydride (2%) according to respective standard and by hot press method. Then specimens were exposed to white (Coriolus versicolor) and brown-rot (Coniophora puteana) fungi according to BS 838:1961 standard and Kollescale method at 8, 12 and 16 weeks. After that, superficial damage, weight loss, and hardness strength of samples were determined. The results showed that superficial damage of brown-rot fungus was lower than white-rot fungus. The weight loss of white-rotted samples were significantly (P

In study, the influence of flour content and immersion time in water on the creep behavior of composites made from mixes PB (Particle Board) and MDF (Medium Density Fiber Board) flour and high density polyethylene (HDPE) waste and was investigated. Mixing was done by a twin screw extruder and the sample was manufactured by flat hot press. Firstly, the modulus of elasticity and bending strength of various mixes PB and MDF flour-polyethylene composites (WPCS) were measured before performing the creep test.It was shown that the modulus of WPCs increases with the increase in mixes PB and MDF flour content from 60% to 70% and then decreases as the flour content reaches to 80%. It is found that the bending strengths of WPCs significantly and linearly decreases with the increase in flour content from 60% to 80%. The results showed that, the creep strain decreases as the lignocellulosic flour level increases. Water absorption has negative effect on creep behavior of mixes PB and MDF flour/HDPE composites. For all filler contents, it can be seen that the creep strain increases when the immersion time increases.

The possibility of producing wood-plastic panels using two methods including melt blend and dry blend was studied in this research. Methods were compared with each other in order to select the best. Wood-Plastic panels were made from high density polyethylene (as resin) and particle board waste (as natural fiber) at 60, 70 and 80% by weight fiber loading. Density and dimensions of the panels were lg/cm3 and 35*35*1 cm, respectively. Mechanical properties of the panels including flexural modulus, flexural strength, screw and nail withdrawal resistance, and impact strength were under investigation. Maximum values of flexural modulus of wood plastic panels were found at 70% fiber content in both methods. Flexural strength, screw and nail withdrawal resistance and impact strength of wood plastic composites reduced with the increase in fiber content from this is not a reduction 60% to 80% is increase. Mechanical properties of samples made with dry blend method were generally higher than those of samples made with melt blend method for an corresponding formulations.

The possibility of producing wood-plastic panels using melt blend method was studied in this research and mechanical properties of the panels including flexural modulus, flexural strength, screw and nail withdrawal resistance, and impact strength were studied.Wood -Plastic panels were made from high density polyethylene (as resin) and MDF waste and particleboard waste (as natural fiber) at 60, 70 and 80% by weight fiber loading. Density and dimensions of the panels were 1g/cm3and 35*35*1 cm, respectively. Results indicated that the mechanical properties of the composites are strongly affected by the proportion of the wood flour and polymer in the material. Maximum values of flexural modulus of wood plastic panels were found at 70% fiber content in both methods. Flexural strength, screw and nail withdrawal resistance and impact strength of wood plastic composites reduced with the increase in fiber content from 60% to 80%.

In this research, the effect of adding SiC nanoparticles on the hardness and wear behavior of A380 aluminum alloy was investigated. A380 aluminum powder and SiC nanoparticles with values of 0, 0.5, 1, and 2 wt.% were ground in a planetary ball mill in argon atmosphere for 10 hours. The weight ratio of ball to powder and the rotation speed was adjusted at 1:10 and 250 rpm, respectively. After the milling process, a hot press was used to produce the samples. The products were produced through a graphite mold with a diameter of 15 mm at a heating rate of 10 °C/min to a final sintering temperature of 520 °C and a holding time of 30 minutes in vacuum under pressure of 50 MPa and were placed in the hot press machine. The microstructure and hardness of the samples were examined using an optical microscope and Vickers hardness tester apparatus, respectively. The wear resistance was evaluated by pin-on-disk method. The greatest hardness of the samples was related to the aluminum alloy containing 0.5 wt.% SiC nanoparticles. AlA380-2 wt.% SiC nanocomposite represented the highest wear resistance compared to the other experimented samples. [ABSTRACT FROM AUTHOR]

In this article, the microstructure and compressive strength of A380 aluminum alloy with the addition of SiC (Silicon carbide) nanoparticles were investigated. A380 aluminum powder and SiC nanoparticles with amounts (0.5, 1, and 2 wt%) were milled in a planetary ball mill in an argon atmosphere for 10 hours. The weight ratio of ball to powder was 1:10 and the rotation speed was set at 250 rpm. After the grinding process, a hot press was used to produce samples, the products through a graphite mold with a diameter of 15 mm at the same time with a heating rate of 10 °C/min to a final baking temperature of 510 °C with a holding time of 30 minutes under vacuum at a pressure of 50 MPa was placed in a hot press. The microstructure and formed phases of the produced samples were investigated using scanning electron microscope (SEM) and X-ray diffraction (XRD). Universal testing machine (UTM) was used to test the compressive strength. It was observed that agglomeration occurred with the increase of SiC nanoparticles, which decreased the mechanical properties. The best density and compressive strength of the samples related to aluminum alloy with 0.5% by weight of SiC nanoparticles were obtained. Also, due to the low sintering temperature, SiC did not decompose and the intermetallic compound of aluminum with carbon or aluminum with silicon was not formed. [ABSTRACT FROM AUTHOR]

The purpose of this research is to investigate the physical and mechanical properties of the wood-plastic nanocomposite made using Blank and Functionalized carbon nanotubes (CNTs). For this purpose, wood flour at a fixed amount of 50%, Blank CNTs at three levels of 0, 1 and 2% and coupling agent at two levels of 0 and 3% and the balance HDPE matrix were used. Also, Functionalized CNTS were used to strengthen the efficiency of nanocomposites at 1 and 2% levels separately. The materials were mixed in an internal mixer (Haake) and then the samples were made by a hot press machine. The results showed that by increasing the amount of CNTs from 0 to 2% wt, the tensile strength and modulus of the samples increased by 58.8% and 12.6% respectively, and water absorption and thickness swelling decreased by 54.5% and 19.4% respectively. Composites containing 2% wt of CNTs showed higher impact resistance compared to control samples. The coupling agent had a positive effect on the performance of nanocomposites. The physical and mechanical properties of the samples were significantly improved by adding the coupling agent and Functionalized CNTs. The results were also confirmed by scanning electron microscopy. [ABSTRACT FROM AUTHOR]

Background and Objectives: In the past two decades, sustainable biological nanomaterials like nanocellulose, encompassing bacterial nanofibers cellulose and wood cellulose nanofibers, have received considerable attention among researchers for diverse product applications. Key attributes such as biocompatibility, biodegradability, renewability, cost-effectiveness, abundant raw material availability, suitable mechanical properties, and safety stand out as pivotal features of biological nanomaterials. Leveraging these properties has led to the creation of numerous applications within various industries. An intriguing product arising from this realm is nanofilm, which is crafted through hydrogen bond formation between cellulose nanofibers, obviating the need for additives or adhesives during production. When utilized as a reinforcement in layered nanocomposite construction, bacterial cellulose nanofibrils (BCNF) and wood cellulose nanofibers (WCNF) exhibit exceptional reinforcement capabilities owing to the inherent cellulose network structure. The recent surge in nanocomposite production emphasis, property optimization, and utilization of high-tech products underscores the growing significance of nanofibrillated cellulose. Recognizing the technical and practical significance of cellulose-layered wood nanocomposite, cellulose nanofilm layers, and the nanocomposites derived from them, coupled with the imperative to thoroughly investigate and evaluate these materials for prospective applied research, this study aims to assess and compare the physical and mechanical properties of cellulose layered wood nanocomposites and bacterial nanocomposites. Materials and Methods: In this study, wood cellulose nanofiber gel and bacterial cellulose nanofiber film were employed. To create wood cellulose nanofiber layered nanocomposites, an initial wood cellulose nanolayer was fabricated using wood cellulose nanofibers and a vacuum-filtration method. Subsequently, the nanolayers underwent solvent displacement with ethanol and acetone through multiple cycles. A mixture of epoxy resin, hardener, and acetone in a 20:10:70 ratio was prepared and agitated on a magnetic stirrer to eliminate bubbles. The cellulose nanolayer was then coated with this epoxy resin, stacking four layers atop one another to form a layered nanocomposite, which was then subjected to a heat press machine and dried for 3 hours at 60 °C. The manufacturing process for bacterial cellulose layered nanocomposites mirrored that of wood cellulose layered nanocomposites, with the distinction that the bacterial cellulose nanofiber film was dried in a hot press at 70 °C for 3 hours to create the bacterial cellulose nanolayer, followed by the assembly of the respective layered nanocomposite. The properties of the resulting nanocomposites were evaluated using various tests, including scanning electron microscopy (FESEM), X-ray diffraction (XRD), infrared spectroscopy (ATR-FTIR), static tension, and water absorption assessments. Results: The study revealed that the average diameter of bacterial nanocellulose and wood nanocellulose measured 45±15 nm and 38±16 nm, respectively. The water absorption of the layered nanocomposite was lower than that of the nanolayer in both nanostructures. Notably, the XRD peaks of bacterial nanocellulose and wood nanocellulose exhibited distinct patterns, with crystallinity levels calculated at 87% and 69%, respectively. Furthermore, the elastic strength, Young's modulus, and strain of the layered nanocomposite composed of bacterial nanocellulose surpassed those of the equivalent composite made from wood nanocellulose. Conclusion: The layered nanocomposites crafted from cellulose nanofibers showcased commendable physical and mechanical attributes, including minimal water absorption and heightened durability. Given these promising characteristics and the escalating interest in related research, it is anticipated that these materials will soon find expanded applications in diverse sectors such as aerospace, automotive, medical and biomedical engineering, food production, film industry, electronics, and magnetism, among others. [ABSTRACT FROM AUTHOR]

Background and Objective: Nowadays, in metropolitan areas, principled and hygienic waste management is very important. Recycling is one of the most appropriate options in waste management. Hereof, the present study was aimed to investigate the possibility of using textile waste fibers in the manufacture of Medium Density Fiberboard (MDF). Materials and Methods: This experimental study was performed on lab-scale. Fabric waste was prepared by separation method at source from a clothing manufacturer in Tehran and converted into fibers. Test boards were made with weight percentage of mixing textile waste fibers to industrial fibers at three levels of 0:100, 10:90 and 15:85, respectively, 10% urea-formaldehyde adhesive, with 16 mm thickness and 0.7 g/cm³ density by hot press. Then, properties of the boards were measured including bending strength, modulus of elasticity, internal bond, hardness, water absorption and thickness swelling. The results were analyzed with ANOVA test. Results: The results of ANOVA showed that the effect of textile waste fibers on the bending strength, modulus of elasticity and swelling thickness of 2 and 24 hours of boards made at 5% probability level was significant. Additionally, the highest values of physical and mechanical properties are related to made boards with 10% of textile waste fibers. Conclusion: The results showed that it is possible to make MDF with textile waste fibers. The use of wastes such as fabrics in the production of new functional products can be considered as one of the strategies to reduce waste and thus to maintain human health and the environment. [ABSTRACT FROM AUTHOR]

The sintering of ZrB2 presents significant challenges due to its covalent bonding and the high temperatures required for the process. Prior research has demonstrated that incorporating up to 20% by volume of SiC as an additive can enhance both the sintering process and the mechanical properties of ZrB2-based composites. The objective of this study was to fabricate and characterize an ultra-high temperature ceramic composite composed of ZrB2 containing 20 vol. % SiC, utilizing the Spark Plasma Sintering (SPS) method with a multi-step approach at various temperatures. Additionally, the study sought to investigate the influence of a TiC additive on the microstructural evolution and mechanical properties of the composite. The research focused on assessing the impact of sintering temperature, ranging from 1600°C to 1900°C under a pressure of 30 MPa, in the presence of a 10 vol. % TiC additive. The introduction of up to 10% by volume of TiC into the ZrB2-20 vol. % SiC composite, followed by sintering at 1800°C for 5 minutes, resulted in the formation of (Zr,Ti)B2 and (Ti,Zr)C solid solutions within the matrix. These solid solutions, along with reactions involving surface oxides such as ZrO2 and B2O3, contributed to a 15% increase in relative density. Furthermore, notable enhancement was observed in the mechanical properties, including a 14% increase in hardness, a 12% increase in elastic modulus, a 20% increase in fracture strength, and an 8% increase in fracture toughness. A comparative analysis with previous studies revealed that employing a multi-step SPS technique, as opposed to a single-step process, significantly reduced the temperature and time of the process to achieve a relative density exceeding 99%. However, it was also observed that increasing the maximum sintering temperature to 1900°C in the ZrB2-20 vol. % SiC-10 vol. % TiC composite resulted in excessive grain growth and a slight decrease in relative density by approximately 1%. [ABSTRACT FROM AUTHOR]

Nowadays, there is a growing demand for the consumption of cold pressed oils. The significant issue about this method of extraction are low extraction yield and bioactive compounds compared to thermal methods. To overcomethis problem, new thermal pre-treatments of seeds before pressing havebeen used. Microwave pretreatment is a modern method that hasbeen presented to obtain highquality oils with higher extraction yield. In the present study, the effect of pre-treatments of pistachio nuts by roasting and microwaving prior to oil extractionby pressing, onthe efficiency as well as the quality of the oil was investigated. Pistachio samples were treated with microwave oven (2450 MHz frequency) for 60, 120 and 180 seconds and for oven-pretreatment three levels of temperature (120, 150, and 180°C) for 15 minutes was applied. Also, in order to obtain the real amount of the pistachio oilextraction yield, untreated samples were extracted by solvent. Hot pressing was performed at three temperature levels of 60, 80 and 100°C, to compare with the other thermal pretreatments. All the oil samples were then analyzed for their yield and the quality properties. According to the obtained results microwave and oven pretreatments increased the extraction yield and oxidative stability as well as chlorophyll content of the oil. The results showed a decrease in oil acidity of the microwavepretreated for 180 sec. however, different pretreatment methods had no significant effect (p<0.05)on carotenoid content of the pistachio oil. Totally, microwave pretreatment is an appropriateprocess before cold pressing of pistachio nuts, which improves the yield and quality properties and oxidative stability of pistachios oil. [ABSTRACT FROM AUTHOR]

In this study, the effect of the perlite nanoparticles on the mechanical properties of a pearlite/NR/HDPE nanocomposite was experimentally investigated. A high-density polyethylene/natural rubber/perlite nanocomposite was synthesized using an internal mixer and a melt mixing method, with varying compositions. Uniaxial tension tests were carried out to obtian the tensile strength and elongation of the samples. The response surface method and the central composite design were employed as experiment design and optimiztion tools to obtian the influence of composite composition parameters, specifically, the weight percentage of perlite and natural rubber. Furthermore, scanning electron microscopy was utilized to inspect the microstructure of the nanocomposite samples, and to evaluate the efficacy of the mixing method. The experimental results derived from the various samples revealed that a sample containing 7 wt.% perlite nanoparticles and 20 wt.% natural rubber demonstrated a significant enhancement in the tensile strength, reaching up to 12 MPa. Moreover, the multivariable optimization data suggested that the optimal weight percentages for natural rubber and perlite nanoparticles were 36.89% and 3.00%, respectively. Under these conditions, both the tensile strength and the elongation at failure point achieved their maximum values, recorded as 8.32 MPa and 38.89%, respectively. [ABSTRACT FROM AUTHOR]

Conductive polymer matrix nanocomposites are suitable choice as a conductive material. Conductive polymer composites with segregated structure has lower percolation threshold than random composites. Reinforcement in Segregated structure composites are only located at polymers matrix particles interface instead of being distributed randomly throughout the system. In this study, HDPE/CNT nanocomposites with segregated structure were fabricated by dry mixing method in order to achieve significant conductivity at low weight percentage of conductive phase, due to improvement of mechanical properties, the second polymer phase, which a lower molecular weight polymer matrix, was added to composites structure. SEM images confirms that the presence of CNTs at polymer granules boundaries. The conductivity in 1%wt of CNT phase for composite without second polymer phase equal 1.0491 S/m and composite with second polymer phase was 0.4518 S/m and In case of LDPE phase, the threshold was reported as 0.07999 Vol% and in the absence of this phase as 0.07999 Vol%. Tensile test results also show that improved mechanical properties for L2CNT composite compared to H-2CNT. The yield stress and fracture strain in the presence of LDPE phase have increased by 26.11% and 208.62%, respectively. [ABSTRACT FROM AUTHOR]

Background and Aims: Endocrown is a type of monoblock restoration using the pulp chamber and remaining coronal tooth structure for retention. Advancements in adhesive techniques have breathed fresh spirit into endocrown. Nowadays, there are two approaches for endocrown: conventional approach and biomimetic approach. This study aimed to review data on the steps and clinical and philosophical points of using these approaches to help dentists' selection and performance. Materials and Methods: The review was conducted by reviewing the articles available in PubMed, Scopus, and Google Scholar databases from 1995 to 2022. The keywords used were; Crown, Endodontically-treated teeth, Light-curing of dental adhesive, Onlay, and Post-Core. Results: After removing duplicates, titles/abstracts were reviewed. Animal studies, studies without available full text or non-English language studies were excluded from the study. Then, the full texts of the remaining 59 articles were evaluated and 49 articles were eligible for the present study. The articles included clinical trials, in vitro, systematic reviews, and case reports. Conclusion: Endocrown is a successful alternative to crown, especially in molar teeth. Regardless of the conventional or biomimetic approach, this treatment has a more favorable fracture pattern while preserving the remaining tooth tissue as much as possible. [ABSTRACT FROM AUTHOR]

This study aimed at the application of unmodified (G) and modified graphite (EG) materials as a multifunction additive to the UF resin for improving the properties of medium density fiberboard (MDF). For this purpose, expanded graphite EG was synthesized from graphite using the Tsai et al (2011) method. Then, as-synthesized EG was intercalated with manganese dioxide by Schwarz et al (1995) method and converted to MnO2-EG. Both additives were individually added to the urea formaldehyde resin in three doses of 1, 2 and 3% (based on the dry weigth of UF resin) to make the MDF panels with 750 kg/m3 nominal density. During the pressing time, the tT0°c parameter (time to reach temperature100٥C) of the middle layer of the board under the influence of the additive was determined by a chromium-nickel-based thermocouple. The treatment of MnO2-EG3 (amount of 3% modified expanded graphite) showed the highest effect in reducing tT100°C of the middle layer of the board by 22%. In addition, the elastic modulus increased by 68% as a result of this treatment. G and EG additives showed a higher degree of internal bonding compared to MnO2-EG additive. In this regard, EG2 and EG3 treatments showed 42% increase in internal bonding and G2 treatment showed 40% increase in internal bonding. The effect of EG2 treatment in improving TS24 was greater than other treatments, so that it caused a 19% decrease compared to the control. [ABSTRACT FROM AUTHOR]

In the present study, metallurgical tests including quantometry, X-ray diffraction analysis, and microstructural investigations with optical and scanning electron microscopes were emplyed to investigate the effect of composition and microstructure on the mechanical properties of the cast ingots and extruded profiles manufactured in Balouch Aluminum Company. Results showed that the concentrations of Fe, Si and Cu were higher than the standard composition of 6063 Al alloy. Optical micrographs sowed that pores were mainly observed at the center of ingots. According to XRD analysis, in addition to FCC phase, an iron aluminide intermettalic phase was identified in the structure of ingots. The formation of intermetallic phase was confirmed by energy dispersive analysis attached to the scanning electron microscope. Tensile test results illustrated that the presence of pores and the distribution of intermetallic phases declined the strength and formability of the alloy. The ultimate tensile strengths at the surface and center of the ingot were 103 and 71MPa, respectively. Fractography of samples indicated that the presence of pores and the intermetallic phase led to a combination of ductile and brittle fracture durin tensile test. [ABSTRACT FROM AUTHOR]

In this research, the tensile properties of polypropylene/natural rubber composite reinforced with perlite nanoparticles produced using a biaxial internal mixer were studied. The mathematical modeling of analysis of variance using the surface response method was used to confirm the experimental results. The role of each materials variable and the weight percentage of natural rubber and pearlite nanoparticles on the tensile properties of the new nanocomposite samples was investigated. It was observed that the values of tensile strength and elongation at break by increasing the amount of natural rubber from 20 wt.% to 40 wt.% and the constant amount of perlite nanoparticles at 3 wt.%, decreased by 14.68% (from 8.92 to 7.61 MPa) and increased by 72% (from 51.05% to 87.81%), respectively. The results obtained from the parameters optimization showed that the maximum values of tensile strength and elongation at break are 8.332 MPa and 74.38% was obtained in the sample with 3.268 wt.% of natural rubber and 4.046 wt.% of perlite nanoparticles, respectively. The scanning electron microscope images showed the positive effect of adding nanoparticles to the polypropylene/natural rubber composite due to the reduction in the size of the elastomeric phase and as a result, the increase in the tensile strength of the composite samples. Also, the proper dispersion of nanoparticles in the polymer matrix phase occurred in the sample with 5 wt.% of perlite nanoparticles and 30 wt.% of natural rubber. However, with increasing the weight percentages of nanoparticles up to 9 wt.%, some agglomerations of pearlite nanoparticles were observed in the thermoplastic phase. [ABSTRACT FROM AUTHOR]

Background and Objective: Nowadays, in metropolitan areas, principled and hygienic waste management is very important. Recycling is one of the most appropriate options in waste management. Hereof, the present study was aimed to investigate the possibility of using textile waste fibers in the manufacture of Medium Density Fiberboard (MDF). Materials and Methods: This experimental study was performed on lab-scale. Fabric waste was prepared by separation method at source from a clothing manufacturer in Tehran and converted into fibers. Test boards were made with weight percentage of mixing textile waste fibers to industrial fibers at three levels of 0:100, 10:90 and 15:85, respectively, 10% urea-formaldehyde adhesive, with 16 mm thickness and 0.7 g/cm3 density by hot press. Then, properties of the boards were measured including bending strength, modulus of elasticity, internal bond, hardness, water absorption and thickness swelling. The results were analyzed with ANOVA test. Results: The results of ANOVA showed that the effect of textile waste fibers on the bending strength, modulus of elasticity and swelling thickness of 2 and 24 hours of boards made at 5% probability level was significant. Additionally, the highest values of physical and mechanical properties are related to made boards with 10% of textile waste fibers. Conclusion: The results showed that it is possible to make MDF with textile waste fibers. The use of wastes such as fabrics in the production of new functional products can be considered as one of the strategies to reduce waste and thus to maintain human health and the environment.

The present research has examined the effect of adding Si3N4 on the mechanical and structural properties of NiCrAlY alloy. The structural and mechanical properties of the manufactured samples were characterized by SEM, XRD, microhardness evaluation and pin on disk wear test. Various concentrations of Si3N4 powder (1, 3, and 5 wt.%) were mixed with NiCrAlY powder using a mechanical ball mill. Next, the mixtures were sintered at 1100 °C using the spark plasma sintering (SPS) technique. The XRD patterns indicated that the samples were composed of two phases of solid solution γ-Ni(Cr) and intermetallic compounds β-NiAl. The results of micro-hardness measurements showed that adding 1% Si3N4 to NiCrAlY enhanced the hardness from 418 to 614 HV. However, with an increase in the Si3N4 content from 1 to 5 wt%, the hardness diminished from 614 to 543 HV, and by Adding Si3N4 to the NiCrAlY, its tribological properties were significantly improved. [ABSTRACT FROM AUTHOR]

Mixing wheat flour with other food sources in order to achieve useful nutritional properties to improve physiological and metabolic effects of Cereal products is highly significant. Flour tortilla is a light, flat, non-fermented, and round bread which is mainly made of wheat, Corn and barley flour. In this research, the Mixture Design Technique was used to analyze the effect of simultaneous replacement of soy flour and whey powder on textural and sensory properties of flour tortillas. The independent variables were wheat flour (٪0-%100) soy flour (5%-15%) and whey powder (2% - %10). The results show that changing the ratio of all variables had significant effects on the physicochemical properties studied, statistically. By increasing the replacement a decrease in Aw of product was observed. So that, use of whey powder and soy flour in their highest proportion, significantly reduced the sample thickness whereas adding high proportion of wheat flour led to the production of thicker samples. The results from the TPA tests revealed that there is a meaningful relationship between all variables and texture properties. Samples containing less whey powder demonstrated better mouthfeel and taste. Finally, optimization displayed that the best formulation of the production of protein-rich tortilla contained 83.2% wheat flour, 12.6% soy flour and 4.2% whey powder. [ABSTRACT FROM AUTHOR]

The effect of nanoclay (Cloisite® 15A) was studied in relation to the flow behavior, mechanical and thermal properties of polypropylene/maleic anhydride-g-(styrene-ethylene-butylene-styrene) triblock copolymer (PP/SEBS(15%)-g-MA) blend. In this regard, the composites based on the blend and various amounts of nanoclay (1,3,5 wt%) were melt compounded using an internal mixer at the temperature of 190°C, rotor speed of 75rpm for 12min. The prepared samples were compression molded in a hot-press machine under the conditions of 190°C, 31 MPa pressure for 9 min to obtain the sheets in various thicknesses. The sheets were then cooled to ambient temperature with cooling water at the rate of 1.5°C.s-1. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to study the structure and morphology of the samples. In addition, the mechanical and thermal properties were determined by standard methods. The results of X-ray diffraction and transmission electron photographs confirmed both exfoliated and intercalated structures in the prepared samples. There were balanced strength/toughness properties in all the prepared nanocomposites by addition of both SEBS-g-MA and clay simultaneously. The measurement of rheological properties showed that as the shear rate increased, the apparent viscosity of the samples decreased (shear thinning behavior). Gradual increase in incorporation of nanoclay also decreased the melt flow index (MFI) values. In addition, increases in nanoclay content had an insignificant effect on the thermal behavior and in that respect there were slight increases in degree of crystallinity, heat deflection temperature (HDT) as well as Vicat softening point by slight increase in temperatureThe effect of nanoclay (Cloisite® 15A) was studied in relation to the flow behavior, mechanical and thermal properties of polypropylene/maleic anhydride-g-(styrene-ethylene-butylene-styrene) triblock copolymer (PP/SEBS(15%)-g-MA) blend. In this regard, the composites based on the blend and various amounts of nanoclay (1,3,5 wt%) were melt compounded using an internal mixer at the temperature of 190°C, rotor speed of 75rpm for 12min. The prepared samples were compression molded in a hot-press machine under the conditions of 190°C, 31 MPa pressure for 9 min to obtain the sheets in various thicknesses. The sheets were then cooled to ambient temperature with cooling water at the rate of 1.5°C.s-1. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to study the structure and morphology of the samples. In addition, the mechanical and thermal properties were determined by standard methods. The results of X-ray diffraction and transmission electron photographs confirmed both exfoliated and intercalated structures in the prepared samples. There were balanced strength/toughness properties in all the prepared nanocomposites by addition of both SEBS-g-MA and clay simultaneously. The measurement of rheological properties showed that as the shear rate increased, the apparent viscosity of the samples decreased (shear thinning behavior). Gradual increase in incorporation of nanoclay also decreased the melt flow index (MFI) values. In addition, increases in nanoclay content had an insignificant effect on the thermal behavior and in that respect there were slight increases in degree of crystallinity, heat deflection temperature (HDT) as well as Vicat softening point by slight increase in temperature.The aim of this work is to study effect of nanoclay (Cloisite® 15A) on the flow behavior, mechanical and thermal properties of polypropylene/maleic anhydride grafted-(styrene-ethylene-butylene- styrene) triblock copolymer (PP/15%SEBS-g-MA) blend. In this regard, the composites based on the blend and various amounts of nanoclay (1,3,5 wt.%) were melt compounded using an internal mixer at the temperature of 190oC, rotor speed of 75rpm for 12min. The prepared samples were then compression molded in a hot-press machine under the conditions of 190°C, 31 MPa pressure, for 9 min to obtain the sheets in various thicknesses. Afterwards, the plates were cooled to ambient temperature with cooling water at the rate of 1.5oC.s-1. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to study the structure and morphology of the samples. In addition, the mechanical and thermal properties were carried out by means of the standard methods. The results of X-ray diffraction and transmission electron photographs confirm both exfoliated and intercalated structures in the prepared samples. There is balanced strength/toughness properties in all the prepared nanocomposites via addition both SEBS-g-MA and clay simultaneously. The measurement of rheological properties show that as the shear rate increases, the apparent viscosity of the samples decreases (shear thinning behavior). Incorporation of nanoclay and increasing its content also decreases the melt flow index (MFI) values. In addition, increase in the nanoclay content have the insignificant effect on the thermal behavior so that slight increase in crystallinity temperature/degree, heat deflection temperature (HDT) as well as vicat softening point are obtained.

The use of wood fibers and recycled paper fibers in cement composites has many advantages. Wood fiber reinforced composites are easy to cast or mold into a desired shape, resistant to fire, as well as being resistant to harmful effects of sunlight, rain, and insects. These composites also have low thermal conductivity, a great degree of processing flexibility, in addition to helping eliminate environmental pollution by recycling wood fiber. The present study seeks to investigate the effect of eucalyptus and beech wood flour on the mechanical properties of wood–cement composites. Five levels of wood (0%, 8%, 20%, 32% and 40%) and one level cement (60%) were used. Totally 15 composites were produced. The composites were manufactured using hot press and tested based on DIN 68763 standard. After preparation of test samples, mechanical properties (bending and hardness) and physical properties (water absorption and thickness swelling) were measured. Results showed that addition of both fillers reduced modulus of rupture and increased modulus of elasticity, water absorption and thickness swelling. The Eucalyptus present in composite wood-cement caused a reduction in mechanical and physical properties can use with Beech wood flour.

The purpose of the research is to examine the effect of nanoclay particles and compatibilization of oxidized polypropylene in molten phase on the mechanical and physical properties of wood-plastic composite made from polypropylene and phragmites ausralis flour. For this purpose, polypropylene in molten phase was oxidized in the vicinity of air oxygen and 1-dodecanol alcohol for 2 hours. Then Phragmites ausralis flour with the weight ratio 50% and the polymer phase was mixed with the compatibilizer at two levels (0 and 3%) and nanoclay particles at three levels (0,2, 4%) in an internal mixer for 6 min under the temperature 165 . Finally, the test specimens were prepared by using the hot press with the dimensions 150×150×2 mm. The mechanical and physical properties including tensile and flexural modulus and strengths, Non-izod impact strength, long term water absorption and thickness swelling were examined according to ASTM standards. The results showed that the using oxidized polypropylene as compatibilizer improves all physical and mechanical properties of the composite. They also showed that increasing nanoclay particles, the physical and mechanical properties of the wood-plastic composite improve, except the Non-izod impact strength. The structural studies of composite and the way the nanoparticles are distributed using x-ray diffraction spectroscopy and SEM images showed that the distribution of nanoclay particles in polymer matrix is of the type of intercalated structures.

Glass fiber/phenolic composites are effectively used as heat shields for fabrication of cooled combustion chambers. To improve the performance of these composites as well as to lower their costs, the use of nanosized silicon dioxide (SiO2) particles has been adopted. In this work, we investigated the effect of nanosilica on properties, heat stability and ablation properties of glass fiber/phenolic composites. Glass fiber/phenolic/nanosilica composites were made of 1, 2 and 3 wt% of well-dispersed silica nanoparticals in a phenolic resin. The average size of silica nanoparticals was 45 nm. These nanocomposites were prepared by hot-press process. Ablation properties of the composites were studied by oxy-acetylene torch environment and their mass and linear erosion rates were evaluated. The thermal stability of the produced composite structures was examined by means of thermal gravimetric analysis in air with dynamic scans at a heating rate of 10°C/min from room temperature to 800°C. Bulk samples, of about 20 ±1 mg each, were tested. The results indicated that nano-SiO2 increased the thermal stability of nanocomposites so that their linear and mass erosion rates after modifying with 3 wt% nanosilica dropped by 58% and 53%, respectively. The 3-point bending test results showed that bending strength and modulus of the as-received composites increased with percentage nanosilica added up to 2 wt%, beyond which they decreased. For the glass fiber/phenolic composites with 2 wt% nanosilica particles, embedded in the matrix, strength and modulus increased about 40% and 19%, respectively, in comparison to those for neat glass/phenolic composite.

This study was performed to evaluate the leaching rate of copper nanoparticles in combined impregnation-densification treated poplar and spruce wood after accelerated aging. Specimens were prepared by impregnation with 200 and 400 ppm nano-copper suspensions, followed by pre-steam treatment and densification. Impregnation was done in a sealed vessel with 4 bar pressure in 20 minutes. Half of the specimens were oven-dried and steamed at 150°C for 2 hours and immediately densified under the hot press at 170°C for 3 hours to reach to the 33% compression rate. All specimens were exposed to the 6 steps accelerated aging procedure according to ASTM D-1037. Leaching test was performed according to EN84 standard (1997) for a period of 14 days. The leached residues were investigated in the Mineral Exploration and Geological Center by atomic absorption method. Results showed that nano-copper particles in impregnated specimens had no leaching; but the pre-steaming and densification treatments led to leaching the nano-copper particles from the treated wood.

Nowadays Paulownia as the fast growing species has noticed for wood industry in the world. In this research, Paulownia fortuni planted in Shaskolateh forest of Gorgan were studied. Two particle form, flour (60 mesh size) and fiber (RMP, L/D= 21/54) were prepared. 60 percent of this material with 37% of HDPE , 3% of MAPE were blended separately. Part from this material by internal mixer and other part by extruder blended. Output was prepared like pellets. Samples were prepared in dimensions of 30cm×30cm×1cm, and nominal density 1 g/cm3 by hot press. The mechanical testing of the panels (flexural, hardness, unnotched impact strength) and the physical testing of the panels (thickness swelling and water absorption after 2 & 24 hours immersion in water) were measured. The result showed that modulus of rupture, hardness, unnotched impact strength of composite made of fiber-PE were lower than composite made of flour-PE. Flexural elastic modulus of composite made of fiber-PE were higher than flour-PE. Water absorption and thickness swelling of composite made of fiber-PE were higher than flour-PE. Also physical and mechanical properties of composites blended by internal mixer improved in compared composites blended by extruder. Physical and mechanical properties of composite made of fiber-PE blended by internal mixer improved in compared composite made of fiber-PE blended by extruder.

Natural rubber and styrene butadiene rubber (NR/SBR) reinforced with short nylon fibers along with nanoclay (Cloisite 15A) hybrid composites were prepared in an internal and a two roll-mill mixer by a three-step mixingprocess. The effects of fiber content at a constant loading of 3 wt% nanoclay were studied on the microstructure, mechanical and morphological properties of the prepared nanocomposites. The adhesion between the fiber and the rubber was enhanced by the addition of a dry bonding system consisting of resorcinol, hexamethylene tetramine and hydrated silica (HRH). The curing characteristics of the composites were determined and subsequently vulcanized at 150°C using a hot press. It was observed that the cure time and swelling index of the composites decreased while maximum torque, and cure rate increased with increasing of short fiber and nanoclay contents. Thestructure and fracture surface morphology of the nanocomposites were characterized using X-ray diffraction, scanning electron microscopy. X-ray diffraction results of nanocomposites indicated that the interlayer distance of silicate layers increased. The mechanical properties (tensile, tear strength, elongation-at-break and hardness) ofnanocomposites containing virgin and waste fibers in the longitudinal direction are compared.

Nanocomposites based on phenolic resol and novolac resins and Cloisite 30B were prepared. Different kinds of phenolic resins and clay content were studied with respect to the morphology and mechanical properties of the polymer silicate layers. The phenolic resins, namely resol, novolac and their mixture and four different percentages of clay contents, 0.5, 1, 2 and 5 wt% have been considered. XRD analysis has been used to investigate clay distribution in the prepared polymer matrices. Chopped strand mat glass fiber was impregnated with each phenolic resin solution and after hand-lay-up, specimens were prepared by hot press compression molding. The mechanical properties of the nanocomposites were assessed by tensile, flexural and Izod impact tests. XRD results show that the degree of clay distribution in resol type phenolic resin is more satisfactory than novolac resin. Based on mechanical properties evaluations, the novolac nanocomposites showed better mechanical properties than other systems under study. The mixture of novolac resin and resol showed improved mechanical properties relative to each phenolic system. The final results indicate that nanocomposites with 2 wt% clay content show maximum modulus and tensile strength increased by 23%. Impact test results also show that optimum properties can be achieved with 2 wt% clay content.

Polyvinyl butyral (PVB) was synthesized by condensation reaction of polyvinyl alcohol (PVA) with butanal in aqueous medium containing an effective emulsifier and an inorganic acid as catalyst. The product was characterized by, IR, TG and DTG techniques. Percentage of vinyl alcohol groups in the PVB was determined by a chemical method according to a standard method. Some clear and soft film samples containing the PVB and some high boiling point plasticizers were made by hot press. For this purpose plasticizers such as bis(2-ethylhexyl)phthalate (DOP) and bis(2-ethylhexyl) terephthalate (DOTP) were purchased and the triethylene glycol bis(2-ethylhexanoate) (TEGB) was synthesized. The film samples containing 30 percent mixture of triethylene glycol bis(2-ethylhexanoate) and bis (2-ethylhexyl)phthalate with ratio 65/35 showed some improved mechanical and optical properties.

The purpose of this study was to investigate effects of different loading levels and addition of urea formaldehyde and polyethylene on the creep behavior of composites made from wastes of OCC recycling mills. The composites manufactured by hot press method and three-point bending test performed before creep test. In general, the results showed positive effects of additive materials such as urea formaldehyde and polyethylene on the creep behavior of the composites. While adding UF and PE decreased primary and final creep as well as return deformation percentage of the composites. Also the obtained results indicated that remaining creep had higher sensitivity to loading levels compared to primary and final creep. Also the increase of the load levels from 20% to 30% led to an increase in creep content of the composites.

In this study, the effect of two lignin mixing methods on physical and mechanical properties of wood flour- polypropylene composites was investigated. Kraft lignin was extracted from black liquor by acidic method and was mixed with wood flour by physical and chemical methods with ratios of 2, 5 and 10 percent (based on wood flour dry weight). The composites were produced by hot press method after mixing of wood flour, lignin and polypropylene at presence or without MAPP. The physical and mechanical properties of prepared samples were measured according to standard methods. In general, the results showed that adding lignin to composites decreased water absorption in both methods. Also increasing lignin from 2 to 10 percent increased impact strength of composites with or without MAPP. Flexural strength of the composites differed depending on mixing method. Increasing of lignin decreased flexural strength of the composites without MAPP in the physical mixing method where as in chemical mixing method it was increased. It is to be noted that the composites with 5 percent lignin, made with physical mixing method and with MAPP exhibited higher flexural strength than other composites.

Effect of Kraft lignin as a compatibilizer on the short-term water absorption (2 and 24 hours) and mechanical properties of wood flour-polypropylene composites was studied. The black liquor of Chooka pulp and paper mill was acidified and Kraft lignin was extracted by precipitation. The extracted lignin at three levels of 2, 5 and 10 percent was mixed with wood flour by physical mixing method. All materials used were oven-dried. Wood flour, lignin and PP with or without MAPP were used to produce composites by flat hot press method. The results of this study indicated that generally lignin improved physical (short term water absorption) and mechanical properties (flexural modulus, flexural strength and impact strength). The bending test result showed that without MAPP, the composites with 2 and 10 percent lignin exhibited higher flexural modulus and strength, respectively. But at the presence of compatibilizer, the composites with 5 percent lignin exhibited the highest flexural modulus and strength. The composite with 2 percent of lignin exhibited higher flexural modulus and short-term water absorption rather than the composites with 2% MAPP. This result indicated positive effect of lignin in the composites. Also the composites with 10 percent lignin exhibited the highest impact strength and short-term water absorption. But there were no significant difference between the impact strength of composites with 5 and 10 percent lignin.

Effect of immersion temperature on long-term water uptake behavior of HDPE/wood sawdust Composite was studied in this research. Panels of wood plastic composites (WPCs) were manufactured from a mixture of sawdust of wood and High density polyethylene powder at 60% by weight filler loading at constant temperature and pressure using a dry blend/hot press method. The nominal density and dimensions of the panels were 1g/cm3 and 35×35×1 cm3, respectively. Specimens were cut from the panels based on DIN-EN 317 standard. The prepared specimens were immersed in distilled water‍ at 20, 40 and 60ºC to measure long-term water absorption. The results showed that water absorption in HDPE/wood sawdust composite proved to follow the kinetics of a Fickian diffusion process. By increasing the immersion temperature, the time to reach to maximum value of water absorption decreased and maximum value of water absorption increased. Diffusion coefficients were affected parabolically by immersion temperature.

The main limitation of the use of adhesive joints is susceptibility of the adhesive layer to damaging environmental factors such as humidity. Use of numerical methods for predicting the strength of adhesive joints exposed to moist environment can save a significant amount of time and cost. In this study, first, experimental investigation and numerical modeling of the complete process of moisture diffusion into the adhesive layer and its damaging effect on the adhesive joint strength were determined. Then this process was applied for a single lap joint of SBT 9244 pressure sensitive adhesive and AL2024-T3 aluminum alloy substrate with two 12.5 and 50 mm overlap of lengths. In the first step, moisture distribution for 30, 60 and 90 days exposure time in environmental condition of 100% relative humidity was obtained. Then single lap joint tensile test was simulated using cohesive zone model for different exposure times. In this simulation cohesive zone model parameters were determined in such a way that numerical failure load and the existing experimental failure load were in good agreement. The cohesive zone model parameters were determined depending on the moisture content. The first simulation was done without considering swelling and in the second, swelling was considered. Swelling stress was obtained separately at different exposure time periods. It was found that swelling effect was more considerable in the joints with longer overlap length and shortened exposure time. [ABSTRACT FROM AUTHOR]

In this article the effect of hot rolling process on properties and microstructure of Al-B4C composite is investigated. To produce the composite samples, 3 vol.% B4C particles with 300 nm average grain size added to melted Al-356 alloy. Rolling process was done at 350 °C on vortex samples that is made after 15 minutes mixing at 850 °C. Porosimetry, hardness and tensile strength tests were carried out to investigate the physical and mechanical properties of composite samples. Microstructures of the samples were also investigated by using scanning electron microscopy. The results indicate lowering the amount of porosity, increasing hardness and increasing tensile strength of rolling composites. The amount of porosity before rolling process was 2.05% that is decreased to 0.35% after rolling process. Tensile strength and hardness of composites before and after rolling process achieved 178 MPa and 293 MPa and 62 HBN and 101 HBN respectively. Also hot rolling process caused to more ductile fracture of composites that is produced by vortex. [ABSTRACT FROM AUTHOR]

Phenolic resin composites reinforced with short carbon fiber are one of the most usable materials in ultra-high-temperature applications such as thermal protective in aerospace industries. In this work, novolac type of phenolic resin matrix was modified with graphite nanoparticles to prepare multi-layered nanocomposites. The effect of graphite nanoparticles was studied on the thermal stability, ablation and mechanical properties of novolac/short carbon fiber composites to achieve nanocomposite with optimum properties for ultra-high-temperature applications. In order to evaluate thermal stability and ablation properties of composite and nanocomposites, a sample containing 40 wt% short carbon fiber was prepared as a reference and the structure of its polymeric matrix was modified with nanographite particles. The amounts of nanographite powders in nanocomposite samples were chosen as 6, 9 and 12 wt%. XRD Spectroscopy was used to study and investigate the dispersion of the graphite nanoparticles and morphology in the polymeric matrix. The compression molding under hot press method was used to fabricate the composite and nanocomposite specimens. Thermal properties of the nanocomposites were studied by TGA and oxy-acetylene flame test. Three-point bending and wear tests were performed to measure the mechanical and wear properties of the nanocomposites. The obtained results showed that the addition of nanographite improved the thermal stability, decreased the rate of degradation and at the same time decreased the weight loss and ablation rate of the nanocomposites. Addition of 12 wt% nanographite particles increased thermal stability by about 12% compared to the reference sample. Moreover in nanocomposite with 12 wt% graphite, the rate of ablation decreased by more than 19% compared to the reference composite.