Influence Of Chemical Treatment Research Articles

Influence of chemical treatment and interaction with matrix on room temperature phosphorescence of carbon dots.

In this work, composite materials were formed based on various matrices (polymer and porous cellulose matrix) and carbon dots (CDs) with intense room temperature phosphorescence (RTP). The effect of postsynthesis chemical treatment with citric acid or urea on the optical properties of composites was studied: the increase in carboxy and carbonyl groups lead to an increase of RTP signal which can be seen with the naked eye over several seconds. Fabricated composites demonstrate good stability and reversibility of RTP signal by mild heating. Based on developed CDs, luminescent inks were used for simple demonstration of the data encryption on a paper.

Influence of Chemical Treatment on the Physical and Mechanical Properties of Bamboo Fibers as Potential Reinforcement for Polymer Composites

ABSTRACT The growing concern for environmentally friendly biomaterials has spurred interest in natural fibers as a viable alternative to synthetic fibers in various industrial applications. Chemical treatment of natural fibers is necessary in cases where it is desired to enhance their properties and make them more suitable for various industrial applications. These treatments can remove impurities, increase fiber roughness for better adhesion, and modify surface chemistry, ultimately improving characteristics like tensile strength, thermal stability, and compatibility with matrix materials in composites. In this study, chemical treatments, including Sodium Hydroxide, Ammonium Hydroxide, and Potassium Permanganate, were applied to the Bamboo fibers to modify the fiber structure. The tensile strength, morphological characteristics, and degree of crystallinity of the treated fibers were examined. Results revealed that 5% Sodium Hydroxide treatment for 2 hours significantly improved tensile strength and crystallinity compared to other treatments. Chemical composition analysis, XRD, and FTIR analyses confirmed the removal of impurities and amorphous substances. Density measurements indicated a reduction in volume due to the elimination of low molecular weight impurities, leading to increased fiber density. This research provides valuable insights for the development of sustainable biomaterials in the construction and automotive industries such as wall panels, dashboards and door panels.

The influence of chemical etching on the surface quality of phase components

Large-aperture fused silica phase optical components such as continuous phase plate (CPP) are widely used in large-scale laser devices to achieve beam homogenization and improve beam quality. However, under the action of high-energy lasers, their lower damage threshold seriously restricts their service life and increases cost of using. Compared with other fused silica components, chemical processing technology with hydrofluoric acid solution (HF) is lacking in the processing of phase components because the residual root mean square value (RMS) of phase elements is very high, and it can not guarantee this. Therefore, it is necessary to carry out research on the influence of chemical treatment on phase components. In this paper, we improved the chemical treatment process to achieve the change of residual RMS value not more than 3 nm, and improved the ability of resisting laser damage that the damage threshold of 29J/cm2 was obtained under the test conditions 351nm@3ns. Finally, we successfully mastered the chemical control process of phase components and applied it to the CPPs as other fused quartz materials engineering production process.

Properties of Jute Fibre Reinforced Polymer Composites – A Review

Jute fibres is of great interest to be used as reinforcement in thermoset or thermoplastic composites, in order to provide positive environmental benefits in-terms of degradability, abundance, low density, nominal cost and recyclable. During fabricating the composites, researchers facing complications such as high water absorbing (WA) character, poor incompatibility of fibre with resins, quality variations in fibres, low thermal stability, etc. Therefore, chemical treatments are considered and it will be the most effective way to enhance the interfacial bonding with matrix, improve mechanical strength and less WA as well. Many research works were carried out on the influence of chemical treatment on the properties of jute fibre and their composites. The investigated treatment methods and the impact of chemical treatment on the properties of jute fibre reinforced polymer composites are comprehensively presented in this review.

Influence of Chemical Treatments on the Physical and Mechanical Properties of Furcraea Foetida Fiber for Polymer Reinforcement Applications

ABSTRACT The usage of natural fibers is regarded as the most viable solution for controlling the consumption of synthetic materials. However, the low moisture resistance, stiffness and poor adhesion capabilities restrict their use in several advanced composite applications. Hence, different surface treatments are employed to improve the physical characteristics of natural materials. In this study, the effect of chemical treatments (sodium hydroxide, acetic acid, potassium permanganate and bromodecane) on the surface characteristics and the adhesion capabilities of Furcraea foetida (FF) fiber with epoxy material is evaluated. From the study, it is seen that the chemical treatment (CT) eliminates the O-H functional groups and enhances the hydrophobic characteristics in FF fiber. Furthermore, the CT removes the amorphous organic attachments and improves the crystallinity in the fiber. However, no substantial increase in the thermal stability of FF fiber was observed post chemical treatment. The microscopic analysis of chemically treated FF (CTFF) fiber shows the elimination of organic attachments and developed neat uniform surface structure. The NaOH-treated FF fiber exhibited maximum tensile strength (σt: 241.75 MPa). Whereas the acetic acid-treated FF fiber showed maximum tensile modulus (σm: 6.9 GPa) and interfacial shear strength (IFSS: 0.06 MPa) compared to CTFF and untreated FF fiber (UTFF).

Development and characterization of laminated fiber reinforced bio-Composite From nettle and poly lactic acid fiber

Nettle and Poly Lactic Acid (PLA) fibers are the strongest and best fibers with valuable potential as reinforcement in a composite. In this study, the development and characterization of a multi-layered laminated fibre reinforced bio-composite from nettle and PLA fiber were performed. Prior to molding, the nettle fibers were treated with chemicals such as Alkali and silane and the influence of chemical treatment on the property of nettle fibers were investigated. The characteristics of raw and chemically treated nettle fibers were investigated through chemical composition analysis, mechanical properties, Fourier transform infrared spectroscopy, scanning electron microscopy and water sorption test. Furthermore physical and mechanical properties of the nettle/PLA bio-composite have been analyzed. Twenty (20) samples of treated and untreated nettle fiber and five samples of nettle/PLA fiber reinforcement bio-composites were tested and the results were averaged for comparison with one another. Based on the results obtained, the treated fiber improves tensile strength, has a more uniform and smaller diameter, a clean surface, and has a good appearance compared to untreated fiber. Laminated bio-composites were found to increase initially with the increase of nettle fiber content till 50 weight % and decrease afterwards. Generally, the bio-composite prepared with an equal weight proportion of nettle and poly lactic acid fiber obtained better mechanical properties and tensile strength. Water sorption test results showed that water uptake ability of treated nettle fibers were lower than raw nettle fibers.

Influence of Chemical Treatment on the Spectral and Thermal Behavior of Activated Carbon Obtained from Olive Oil Solid Waste

Solid waste remained after the extraction of oil from olive oil fruits (OOSW), was used to obtain active carbon depending on chemical activation using H3PO4, KOH and ZnCl2 as activating agents. The changes in composition due to chemical treatment and pyrolysis were investigated by chemical analysis, spectral (IR), and thermal analysis (DTA). Thermodynamic parameters of formation (activation energy (ΔEa*), enthalpy change (ΔH*), entropy change (ΔS*) and free energy change (ΔG*) related to the thermal decomposition process were calculated. Adsorption of both iodine and methylene blue at very low concentrations were done, the quantity of the iodine adsorbed (iodine number) indicated the micropores content of carbon by the uptake of iodine from the solution. It is equivalent to surface area of carbon between 900m2/g and 1100 m2/g. To characterize activated carbons as well as determining the adsorption capacity adsorption of methylene blue was done.

Sugar Palm Fibre-Reinforced Polymer Composites: Influence of Chemical Treatments on Its Mechanical Properties.

In the era of globalisation, decreasing synthetic resources, especially petroleum, have encouraged global communities to apply biomass waste as a substitute material for green technology development. The development of plastic products from lignocellulosic fibre-reinforced composites has been a hot topic among material scientists and engineers due to their abundance, sustainable in nature, and less toxic towards health. For the Malaysian scenario, sugar palm is a plant found in the wild and locally planted in certain areas in Malaysia and Indonesia. Generally, sugar palm can be harvested for traditional foods, fruits, starch sugar (gula kabung), and alcohol, whereas sugar palm fibre (SPF) is used in conventional products (brushes and brooms). Various researchers are working on the characterisation of fibre and its composites for engineering and packaging products. The main drawback of SPF is its hydrophilic behaviour, which leads to high moisture uptake and inhibits a good bond between the fibre and the matrix. Thus, a solution for this problem is by implementing chemical treatments on the fibre. From the literature review, no comprehensive review paper has been published on the influence of chemical treatment on the mechanical behaviour of SPF-reinforced polymer composites. Thus, the present review examines recent studies on the mechanical properties of sugar palm lignocellulosic fibres with various chemical treatments to evaluate their potential in structural applications.

Influence of Chemical Modification on Structural, Morphological, Thermal, and Weathering Behavior of Eulaliopsis Binata Fiber and Its Composites

ABSTRACT In the present investigation, the influence of chemical treatment on the structural, morphological, thermal, and weathering behavior Eulaliopsis Binata (EB) fiber was studied. Composites were fabricated containing both untreated and chemically treated (with acetone, alkali, and benzoyl chloride) EB fibers. The mechanical characterization of the developed composites was carried out for both treated and untreated EB fiber composites to assess the effect of chemical modification on the mechanical properties. The maximum tensile and flexural strength were observed for benzoylated fiber composites. The percentage increase in the tensile and flexural strength of 30 weight fraction EB fiber composites was found to be 43.2% and 47.05% with respect to untreated fiber composites. The fractured surfaces of the specimens were studied using a Scanning Electron Microscope (SEM) to explore the fracture mechanisms of the developed composites.

Influence of chemical treatment and surface topology on the blocking voltage of GaAs thyristor mesastructures, grown by MOCVD

The effect of sulfide passivation (chemical treatment in a peroxide-sulfur etchant and in a solution of Na2S in isopropanol) and complication of the profile of the lateral surface of thyristor mesastructures on the blocking ability of GaAs thyristor mesastructures is investigated. It is shown that the blocking voltage of the chips increases several times both after chemical treatment of the surface and with the complication of the surface topology. Keywords: thyristors, blocking voltage, sulfide passivation, gallium arsenide, mesastructure.

Physico-Mechanical Properties of Treated Chicken Feather–Reinforced Unsaturated Polyester Resin Based Composites

The influence of chemical treatment on the mechanical properties of treated chicken feather fibre-reinforced unsaturated polyester resin (TCFF-UPR) composites was studied in this research. Redundant portions of chicken from poultry farms are comprehensively contaminating the environment. To minimize environmental pollution, these redundant portions need to use for the production of other materials. In this study, we used chicken feather for the preparation of useful composites combining with unsaturated polyester resin (UPR) to reduce environmental pollution. The composites were prepared successfully by conventional hand lay up technique using modified chicken feather as the reinforcing phase of composites. For preparing composites different percentages (2, 5, 7, 10, 12 and 15% by weight) of fibre were used. Attained tensile test results expressed significant enhancement in the tensile properties of composites, with the optimum combination of tensile strength presented by 5 wt% , tensile modulus presented by 10 wt% untreated chicken feather bio-fibre reinforcement and bending strength by 5 wt% chicken feather bio-fibre reinforcement.

Influence of chemical treatment and drying method on the properties of cellulose fibers of luffa sponge

The exploration of modified luffa sponge (LS) cellulose fiber in the field of polymer composite can contribute to the development of high-performance and lightweight composites. In this study, two chemical treatments (10%NaOH–20%CH3COOH (Method 1) and 10%NaOH–5%Na2SO3 (Method 2)) and two drying methods (air drying and freeze-drying) were used to treat LS. The microscopic characteristics and physical properties showed that Methods 1 and 2 caused shrinkage of the LS fibers and increased their fiber density by 30.6% and 15.0%. Meanwhile, freeze-drying kept the cells of modified LS fibers full and decreased their fiber density by 5.0% and 21.0%, respectively. The tensile properties test analyses indicated that freeze-drying further increased the elongation at break values of modified LS fibers by 25.3% and 17.7%, respectively. The moisture absorption analyses showed that freeze-drying could further decrease the moisture absorption ratios of modified LS fibers by 25.8% and 35.8%, respectively, which was useful for improving the dimensional stability of composite materials. Moreover, the thermogravimetric analysis reveals that freeze-drying increased onset degradation temperatures of the modified fibers by 24.0 °C and 6.7 °C, which was beneficial to improve the thermal stability of the composite material.

Influence of Chemical Treatment on the Physico-mechanical Characteristics of Natural Fibers Extracted from the Barks of Vachellia Farnesiana

ABSTRACT In recent decades, the production of natural fiber composites has increased due to their biodegradability and lower costs. In the current work, Vachellia farnesiana fibers were selected and extracted by the manual retting process. The obtained Vachellia farnesiana fibers were chemically treated with hydrochloric acid (HCl) and sodium hydroxide (NaOH) solutions. The chemically treated and untreated Vachellia farnesiana fibers were characterized for physical, chemical, tensile, morphological, and thermal properties. Test results showed that the cellulose content was 47.8 ± 0.697 weight % for NaOH treated Vachellia farnesiana fibers with reduced moisture and amorphous contents. HCl treated Vachellia farnesiana fiber showed more cellulose content removal, which resulted in degradation of its properties due to the acidic nature of HCl.

Hybridization and influence of chemical treatment on the morphology and optimization of composites

In the current research the prime goal of author was to examine the properties like tensile, flexural & compressive of the surface customized bio fibers reinforced composites. The legitimacy and gain of utilizing bio fibres was their effective accessibility, small cost, ecological friendly, harmless and biodegradable nature. Even though bio fibres exhibit stupendous physical and mechanical properties, and it also differs with the plant, kind and geology. In the present work Curaua-Bagasse strands were utilized at the following amount: 5, 10, 15, 20, 25 and 30 wt% for the fabrication of composites. Untreated and chemically surface tailored Bagasse-Caraua fibers were reinforced in the epoxy/vinyl ester blend and composites have been prepared by hand lay-up technique. The were alkali treatment was carried out Curaua-Bagasse fibers for different periods namely 12 hrs and 24 hrs in 10% NaOH and examined their morphological and mechanical properties. Benzene diazonium chloride processed composites at 25% wt. fibers amount exposed predominant and ultimate merits than 24 hrs NaOH (alkali) treated, untreated and 12 hrs NaOH treated composites. Because of Benzene diazonium chloride processing the tensile strength of 30%, flexural strength of 26% & compressive strength of 22% was found to increase.

Preparation and Characterization of Ultra-Fine Oil Palm Ash Powder by Ultrasonication and Alkaline Treatment for Its Evaluation as Reinforcing Filler in Natural Rubber.

Ultra-fine oil palm ash (OPA) particles were successfully prepared using ultrasonication along with optimal chemical deagglomeration. The influence of chemical treatment by sodium hydroxide (NaOH) solution on the OPA particles was found to be an important factor in enhancing deagglomeration efficiency. The average particle size of the original OPA (41.651 μm) decreased remarkably more than 130 times (0.318 μm) with an obvious increase of Brunauer–Emmet–Teller (BET) surface area after treating the OPA with 3M NaOH, followed by ultrasonication for 30 min. The changes in particle size and surface morphology were investigated using transmission electron microscopy and scanning electron microscopy. Moreover, the chemical functional groups of the untreated and treated OPA showed different patterns of infrared spectra by the presence of sodium carbonate species owing to the effect of NaOH treatment. The incorporation of both untreated and treated OPA in natural rubber by increasing their loading can improve cure characteristics (i.e., reducing optimum cure time and increasing torques) and cure kinetic parameters (i.e., increasing the rate of cure and reducing activation energy). Nevertheless, the strength, degree of reinforcement, and thermal stability of treated OPA as well as wettability between treated OPA particles and NR were greater than that resulting from the untreated OPA.

Influence of chemical treatment on strain and charge doping in vertically stacked monolayer–bilayer MoS2

We report simultaneous Raman scattering and photoluminescence (PL) mapping results to study the strain and doping effects of chemical treatment with bis(trifluoromethane) sulfonimide (TFSI) on the optical phonon, exciton, and trion characteristics of a vertically stacked monolayer–bilayer (1L–2L) MoS2 structure. Correlation analysis between the E′ and A1′ phonon energies revealed that tensile strain developed in the TFSI-treated MoS2 mainly by the filling of sulfur vacancies: 0.13% and 0.10% for 1L and 2L MoS2, respectively. In addition, TFSI-induced changes in the electron densities evaluated from the Raman correlation analysis were estimated to be −0.38×1013 cm−2 and −1.21×1013 cm−2 for 1L and 2L MoS2, respectively. The larger p-doping effect in 2L than in 1L MoS2 was attributed to a relatively higher defect density in the 2L region of the pristine MoS2, followed by a subsequent healing of the defects via chemical doping. The TFSI-induced change in electron density estimated from the PL result was in excellent agreement with the Raman correlation analysis. Furthermore, the Raman mapping and PL histogram analyses showed that structural defects in MoS2 could be effectively healed by chemical treatment.

Fused deposition modeling of poly (lactic acid)/almond shell composite filaments

AbstractIn this paper, poly (lactic acid)/almond shell powder (PLA/ASP) composite filaments were prepared using the fused deposition modeling (FDM) method. The influence of chemical treatments on the chemical groups of ASP was determined, and the effects of material ratios (3, 5, 10, and 15 wt%) and sliane concentration (2, 4, 6, and 8 wt%) on thermal and mechanical properties of the composites were investigated. The optimal ratio in the PLA/ASP composite was observed at 10 wt% ASP and 4 wt% silane. With the optimal processing parameters, the Td0 (onset temperature) and Td1 (the temperature at the maximum degradation rate) of PLA were enhanced. Furthermore, the tensile and compressive strengths of PLA were increased. Finally, porous scaffolds using PA15S4 filament were manufactured, which have a controllable porosity of 10% to 75%, interconnected pores size of 100 to 900 μm and a satisfy compressive modulus. The results indicated that the PLA/ASP composites have the potential to be used to prepare lighter‐weight parts with internal pores by using FDM.

Influence of Chemical Treatment and Moisture Absorption on Tensile Behavior of Neem/banana Fibers Reinforced Hybrid Composites: An Experimental Investigation

ABSTRACT Hybrid composites composed of neem fiber (N), banana (B) fiber and epoxy resin were fabricated by hand layup method. Three types of composites with blending ratio of B:N (1:4), B:N (1:1) and B:N (4:1) respectively were fabricated and the effects of fiber loading, chemical treatment and moisture absorption on tensile strength of the composites were investigated. The results showed that the fiber loading influenced the tensile strength and the B:N (4:1) composite displayed the superior tensile strength of 52 MPa compared to other composites due to the presence of more amount of banana fiber with high strength. The B:N (1:4) composite exhibited the lowest tensile strength of 47 MPa owing to the presence of more amount of neem fiber with low strength. Chemical treatment of fiber surface improved the tensile strength significantly due to the removal of impurities, lignin and hemicellulose. Silane-treated composite showed the greater tensile strength compared to alkali treated and untreated composites. Silane treated B:N (4:1) composite exhibited 17.5% and 42.3% improvement in tensile strength compared to the tensile strength of alkali treated and untreated composites respectively. Moisture absorption study revealed that the moisture uptake behavior of composite reduced the tensile strength due to the breakage of H-bond. Moisture absorption reduced the tensile strength of B:N (1:4), B:N (1:1) and B:N (4:1) composites by 14.7%, 10% and 5.8% respectively compared to dry samples.

Characterization of Surface Modified Nettle Fibers for Composite Reinforcement

ABSTRACT One of the major issues associated with the use of plant fibers in composite fabrication is their hydrophilic nature, which leads to poor interfacial interaction between the fibers and matrix. Therefore, it is essential to modify the plant fibers prior to composite fabrication. Several researchers investigated the potential use of chemically treated cellulosic bast fibers such as jute, flax, hemp, ramie, and kenaf in composite development. However, there is another natural bast fiber ‘nettle’, which is least investigated for making biocomposites. In this study, nettle fibers were treated with chemicals such as sodium hydroxide, hydrogen peroxide, and sodium chlorite and the influence of chemical treatment on the characteristics of nettle fibers were investigated. The characteristics of raw and chemically treated nettle fibers were investigated through chemical composition analysis, thermogravimetric analysis, Fourier transform infrared spectroscopy, scanning electron microscopy and water sorption test. The results showed that the nettle fiber is a potential reinforcement material for composite fabrication.

Influence of chemical treatment on the properties of cement-paper hybrid composites for ceiling board application

This study evaluates the effect of treated and untreated jute fiber/eggshell particulate reinforced cement-paper matrix composites for ceiling board application. Treated jute fiber (TJF) was obtained by immersing untreated jute fiber (UJF) into 1.25 M sodium hydroxide (NaOH) solution in a shaker water bath maintained at 40 °C for 4 h. Eggshells (ESP) were pulverized and sieved to -75μm. Samples were prepared by varying the fiber volume fraction from 0.5 to 2.5 wt.% in the composites. While other constituents such as the binder (cement) and eggshell were kept constant. An hydraulic press cold compaction molder was utilized in the production of the hybrid composites in a predetermined mix ratio designed based on previous research. The samples produced were cured for 7 and 14 days, then sundried for 36 h. The physical, thermal, mechanical and wear behaviour of the produced composites were evaluated while the surface morphology of the fractured splitting tensile samples were analyzed. The result reveals that TJF/ESP hybrid composites had better performance than UJF/ESP hybrid composites in most of the tests carried out. Increase in the number of curing days was found to also enhance the properties of the composite produced in majority of the test evaluated. The 0.5 wt.% UJF/ESP gave the least performance of all the composites developed. While 2.5 wt. % TJF/ESP showed an optimum properties among the composites tested. When compared with standard, it is concluded that the hybrid composites developed can be suitable for ceiling boards and also find possible application in wall partitioning.