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In this study, it is aimed to produce wood plastic composite material with eggshell additives and to investigate the mechanical properties of these materials. Mechanical properties such as tensile strength and modulus of elasticity, elongation at break, flexural strength and modulus of elasticity and impact resistance of new materials produced by adding eggshell to wood plastic composite at different rates were investigated. It was determined that tensile strength values gradually decreased due to the increase in the amount of eggshell in the composites produced. The modulus of elasticity of the composite material in tensile strength increases with the increase in the amount of eggshell in the mixture. With the increase of the eggshell ratio used, the elongation values of the plastic composite at break are reduced. The eggshell material used in wood plastic composite reduces the bending strength of the material. The eggshell reduces the modulus of elasticity of the composite material in bending. The eggshell composite material did not cause a significant change in impact resistance. [ABSTRACT FROM AUTHOR]

Next-generation laminated wood composites were produced using waste poplar (Populus deltoides) veneer and polyvinyl acetate adhesive. Four experimental groups and one control group were created. Ten-layer laminated wood veneer samples were reinforced with natural rubber (Group A), linoleum (Group B), felt (Group C), and elastomeric sponge (Group D); these materials were used in the fifth adhesive layer (middle layer). The sound absorption coefficients of the control and experimental groups were tested via the impedance tube method, according to ASTM standard E1050 (2006). Attention was paid to the acoustic behavior at low frequencies (63 Hz to 250 Hz), mid frequencies (250 Hz to 2000 Hz), and high frequencies (2000 Hz to 6300 Hz). It was determined that the sound absorption coefficient of the experimental groups considerably increased. It can be suggested that the experimental groups be used as sound absorbing acoustic panels and the control group as sound reflective acoustic panels. [ABSTRACT FROM AUTHOR]

The assessment of self-regulation, which is important for the geometry learning area and can be associated with the stages of the ACE cycle, is important for success. The study was conducted to determine the effect of the ACE cycle-based learning process on students' geometry self-efficacy beliefs in the 7th grade polygons learning area. Quasi-experimental design with pretest-posttest control group, one of the quantitative research methods, was preferred in the study. The study group consisted of a total of 46 students, 24 in the control group and 22 in the experimental group, studying in the seventh grade of a middle school in the eastern Anatolia region of Turkey. In the 4-week implementation, the lessons were conducted according to the ACE learning cycle in the experimental group, while no intervention was made in the control group. In this study, the Self-Efficacy Scale for Geometry was used as a data collection tool and independent sample t-test and dependent sample t-test were used to analyze the data. The results showed that the instruction shaped according to the ACE learning cycle was more effective on students' geometry self-efficacy beliefs in the related learning domain. [ABSTRACT FROM AUTHOR]

The use of different mineral material types and contents in medium density fiberboard (MDF) production was investigated. Three different minerals (sepiolite, dolomite, and perlite) and five different ratios (3%, 6%, 9%, 12%, and 15%) were used according to the oven-dry wood fiber weight. These minerals were homogeneously added as powder between the wood fibers. Some physical, mechanical, limit oxygen index (LOI), and thermogravimetric analysis (TGA) tests of the boards were conducted. The mineral fillers negatively affected the physical properties such as water absorption (WA), thickness swelling (ThS), and mechanical properties such as modulus of rupture (MOR), modulus of elasticity (MOE), and internal bond (IB). However, LOI and TGA test results showed a positive effect on combustion resistance depending on the type and rate of mineral fillers. [ABSTRACT FROM AUTHOR]

The fire properties of particleboard coated with calcite and a variety of fireretardants (FR) was investigated. Four different chemicals, boric acid (BA), borax (BX), dolomite (DOL), and melamine (MEL), were added at the concentration of 1.0%, 3.0%, and 5.0% by oven-dry weight of calcite. The particleboard panels were tested according to the ASTM-E 69 standard to investigate their fire-retardant properties. The determination of weight loss, temperature, and the release of O2, CO, and NO by the samples was measured and recorded over 30 s intervals during combustion of the materials. The results indicated that the BA coatings exhibited better thermal stability than the other chemicals. Consequently, the lowest weight loss and temperature was found for specimens treated with 5.0% BA. These chemicals were effective relative to the fire properties of coated particleboard surfaces, depending on the type and ratio of the chemicals to the calcite. [ABSTRACT FROM AUTHOR]

The effects of the amounts of flour from the red pepper (Capsicum annuum) fruit stem (RPFS), together with coupling agent (CA), on the mechanical and physical properties of polypropylene (PP)-based composites were investigated. Pellets manufactured through single screw extruders were injection molded into composite samples. Density, mechanical property, and dimensional stability of manufactured composites were determined according to ASTM standards. Results were analyzed using central composite design (CCD). Statistical analyses showed that filler loading significantly affected the density, as well as mechanical and physical properties of thermoplastic composites. Density of the composites was increased with filler loading but not affected by coupling agent amounts. In the case of mechanical properties, tensile modulus, flexural strength, and flexural modulus were improved with increasing filler loading while the tensile strengths, elongation at break, and impact strength of the samples were decreased. The tensile strength of the thermoplastic composites was positively affected by CA contents, but other mechanical properties were not affected as much. In the case of physical properties, thickness swelling and water absorption of the composites were increased with increasing weight percent of RPFS flour. However, these properties were not significantly changed by CA addition. Overall results revealed that RPFS flour could be potentially suitable raw materials for thermoplastic composites. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the effects of certain fire-retardant chemicals on the combustion resistance of high-density fiberboard (HDF). Borax (BX), boric acid (BA), ammonium polyphosphate (APP), and alpha-x (AX) were added into the fibers made from 50% scots pine (Pinus sylvestris L.) and 50% beech (Fagus orientalis Lipsky) woods at 3%, 6%, and 9% levels based on oven-dry fiber weight. HDF panels were produced in 6.5 mm thickness. HDF panels' combustion behavior was explored. To detect combustion resistance, the panels were tested according to the ASTM-E 69 and thermogravimetric analysis (TGA) tests. It was determined that fire-retardant (FR) chemicals enhanced the combustion resistance of the panels to varying degrees. As a result, the FR chemicals' type and concentrations are effective for determining the combustion resistance of HDF panels. [ABSTRACT FROM AUTHOR]

This study investigated the tensile properties and thermal behavior of virgin and hot press molded HDPE composites filled with different particle size and content of used beverage cartons which were the Tetra Pak® cartons. The mechanical properties of the composites were positively influenced by particle size of the used beverage carton, such that the smallest particle size gave the highest tensile strength and tensile modulus. The tensile strength of the specimens decreased with increasing filler content (40 to 70 wt%), while the tensile modulus rose. Furthermore, the filler size and its content affected the thermal behavior of the specimens. Calorimetry analysis of composite specimens showed that melting temperature and enthalpy values of virgin HDPE and recycled-HDPE decreased with increasing Tetra Pak® content. In all composite groups produced by adding Tetra Pak®, the degree of crystallinity decreased as a function of Tetra Pak® addition compared to the pure HDPE. Increasing particle size adversely affected the crystallization degree, which decreased with increasing particle size while the HDPE maintained its crystalline form. As for the recycled-HDPE composites, the degree of crystallization was reduced by increasing the Tetra Pak® content, but this was still noticeably higher than that of the HDPE. [ABSTRACT FROM AUTHOR]

The antibacterial performance of biocomposite films prepared from lignocellulosic waste (hazelnut husk or hazelnut leafy green cover) modified with silver nanoparticles and polylactic acid (PLA) was determined. The amount of hazelnut husk in the PLA matrix ranged from 10 to 40% by weight in 10% increments. The composite pellets were produced using a twin-screw extruder. Biocomposite films of 0.6 mm x 40 mm x 200 mm were produced from the pellets in a laboratory hydraulic hot press. The surfaces of the modified hazelnut husk and biocomposite specimens were analyzed by scanning electron microscopy (SEM) and inductively coupled plasma optical emission spectrometry (ICP-OES). The antibacterial activity of the biocomposite films against Staphylococcus aureus bacteria was determined using the ASTM E 2149 (2020) method. The antibacterial activity of the biocomposite films increased noticeably with the addition of hazelnut husk modified with the silver nanoparticles. Compared to the pure PLA film, the biocomposite films with 10 wt% modified husk flour showed the lowest antibacterial activity (31.3%) against S. aureus over 24-h while the films with 40 wt% showed the highest antibacterial activity (99.9%). The biocomposite films made of hazelnut husk flour with silver nanoparticles and PLA matrix could be considered for food packaging applications. [ABSTRACT FROM AUTHOR]

Textile (cotton) dust, which is harmful to humans and the environment, is one of the largest wastes in the textile industry. The aim of this study was to investigate the potential use of this waste in high value-added materials. Physical and mechanical properties and formaldehyde emissions of the three-layered particleboards with textile (cotton) dust in the middle layer were investigated in this study. A phenol formaldehyde resin was used as the binder in particleboard production. Four different amounts of textile dust (10%, 20%, 30%, and 40%) based on the oven-dried weight of the wood were obtained from a commercial textile manufacturer as industrial waste. The density, thickness swelling, modulus of rupture, modulus of elasticity, internal bond, and formaldehyde emissions of the produced panels were determined. The physical and mechanical properties and formaldehyde emissions of the particleboards were negatively affected, which decreased with the addition of a high amount of textile powder. At low rates, the use of textile dust in the middle layer did not significantly decrease the particleboard properties. Textile dust can be a partial solution for the raw material demand of the wood-based panel industry. [ABSTRACT FROM AUTHOR]