Papers by Keyword: Alkaline Treatment

Abstract: This study explores the potential of Lygodium circinatum (commonly known as Nito vine), an underutilized natural fiber in polymer composites, as reinforcement in epoxy-based polymer composites. With the growing shift toward sustainable alternatives to synthetic fibers, Nito fiber presents an eco-friendly and cost-effective option. Sodium hydroxide (NaOH) treatment was applied to modify the fiber surface, and its effects on the fiber–matrix interaction, thermal stability, and mechanical performance were evaluated. FTIR analysis confirmed the successful reduction of non-cellulosic components such as hemicellulose in the treated fibers. SEM micrographs revealed enhanced interfacial bonding between the NaOH-treated fibers and the epoxy matrix, with reduced signs of debonding. Thermogravimetric analysis indicated improved thermal stability in composites containing treated fibers, as reflected by a higher degradation temperature. Mechanical properties such as tensile and flexural strength and modulus, as well as impact resistance, however, did not exhibit significant improvements, which might also be affected by the variability in the natural fibers and the hand lay-up method. These findings emphasize both the promise of Nito fiber as a viable natural reinforcement and the importance of consistent processing methods in composite fabrication. Overall, this work supports the favorable transition toward natural fibers in composite applications, particularly where thermal performance is prioritized.

Abstract: This study explores the use of sodium bicarbonate-treated Nito core fiber as a natural and eco-friendly alternative for fiber-reinforced composites to address the challenge of enhancing the mechanical properties of composite materials while also prioritizing environmental sustainability. Nito core fibers were treated with different concentrations of sodium bicarbonate, an economical and eco-friendly alternative to alkali treatment, to enhance its compatibility with various matrices. FTIR results showed that NaHCO3 treatment effectively removed and reduced some non-cellulosic components present in the Nito fiber such as hemicellulose and lignin. This resulted in the NaHCO3-treated fiber-epoxy composite showing better tensile strength and modulus of elasticity than the epoxy composite reinforced with untreated Nito fiber. The use of treated fiber, however, did not have a noticeable effect on the flexural strength and flexural modulus of the epoxy composite. The SEM images of the nito fiber-epoxy composites showed better fiber-matrix adhesion between the treated nito fiber and epoxy matrix. Thermogravimetric analysis (TGA) of nito fiber-epoxy composites shows that the thermal stability of the composite is mainly due to the presence of cellulose, which can also be enhanced by some lignin. This study, therefore demonstrates the potential of Nito ‘core’ fibers as a viable substitute for synthetic reinforcements that can contribute to the advancement of composite material technology that aligns with the global shift towards environmentally responsible manufacturing practices.

Abstract: Titanium alloys, especially titanium-niobium alloy have been reported as a potential biomaterial with good biocompatibility and non-toxicity. However, there is a lack of studies in alkaline surface treatment of new beta titanium alloy fabricated by vacuum arc melting (VAM) and powder metallurgy (PM) technique with high addition of niobium percentage. The purpose of this research was to examine the feasibility of surface modification on new beta Ti-40wt% Nb alloy in sodium hydroxide solution in order to form bioactive alkaline titanate layer. The characterization involved in this study is X-ray diffraction analysis (XRD), scanning electron microscope (SEM), microhardness, density measurement and optical microscope (OM). Development of amorphous alkaline titanate layer consisted of titanium hydrate, sodium titanate and oxide mixture of titanium oxide, niobium, niobium oxide were revealed by XRD. SEM shows titanate hydrogel layer form on Ti alloy PM thicker than on Ti alloy VAM. Microhardness and density measurement for Ti alloy VAM is greater than Ti alloy PM. OM shows porous surface on Ti alloy PM compare to VAM. This research suggests that the formation of sodium titanate layer on the surface of Ti-Nb alloy enhance bioactivity with better osteointegration and present higher formation of apatite which is crucial for the desired biomedical implant.

Abstract: This paper evaluates the influence of two types of treatments on the tensile related properties of sugar palm fiber (SPF) by using a single fiber test. Natural fibers are one of the vital reinforcing materials in polymer composites due to their positive properties. Sugar palm fiber is a kind of lignocellulose fiber that can be a good potential filler material in fibers/polymer composites for many uses. A Scanning electronic microscope was used to evaluate morphological analyses. Seawater and alkaline solution treatments were used to treat the fiber before the test. The properties of sugar palm fibers improved significantly, as the effect of alkaline concentration by 0.5% and 0.25% improved the tensile properties of a single fiber by 10% and 176%, respectively compared to the untreated fiber. On the other hand, the highest effect on sugar palm fibers was the fibers treated by seawater for 30 days by 273%. Morphologic analyses showed that the treatment plays a big role to clean the surface of the fibers and remove the undesirable impurities. Overall, the results depict that the treatments improve the tensile properties of the single SPF.

Abstract: Wood-plastic composites (WPCs) are composites that incorporate plants composed up of wood and non-wood fibres blended with thermosets or thermoplastic polymers to form a composite. Oil palm trunk (OPT) is one of the wastes produced from the oil palm industry known as oil palm biomass (OPB). The OPT was utilized to turn oil palm biomass into a value-added product. In this research, oil palm trunk/polypropylene (OPT/PP) blends composite was produced by extrusion and injection molding techniques. Alkaline treatment was applied to the fibers to improve the interfacial adhesion of fibers. After alkaline treatment, treated OPT (T-OPT) and untreated (UT-OPT) together with PP were blended at 200°C with the speed of 85 rpm in the extruder to form a pellet. Pellets were then injected in injection molding at 200°C to form sample size for mechanical testing; tensile and impact testing. The physical testing conducted was Melt Flow Index (MFI), water absorption test and Thermogravimetric Analysis (TGA). The results show that the mechanical properties of OPT/PP composite were improved by alkaline treatment. In the water absorption test, T-OPT composite demonstrated lower water absorption than that of UT-OPT composite. This indicated that the reduction of water absorption in T-OPT composite is due to alkaline treatment that degraded the lignin and cellulose structure subsequently reducing the OH groups in fibers to absorb water. For TGA, T-OPT composite had slightly higher thermal stability as compared to UT-OPT composite.

Abstract: To be properly used in the textile industry, the natural materials are subject to different pretreatments. During the scouring, the non-cellulosic attendants (wax, pectin, pigments) are removed. The enzymes have proved their efficiency in this regard but also in terms of being friendly with the environment. The textile industry is a water large consumer, comprising many wet processes: bioscouring, bleaching, mercerizing, and dyeing. The water quantity needed for each step is very high. The resulted wastewater comprises different types of chemicals, most of them non-biodegradable: acids, sodium hydroxide, hypochlorites, peroxides, etc. The actual trends and legislation require the change of classical methods used with ecological ones. One particular reason for this tendency is also related to the economic issue, the use of eco-friendly treatments leading to significant economical savings. The present study was focused on enzymatic treatments with the use of two chelating agents (sodium citrate and EDTA) to remove the flax/cotton fabric impurities. The new proposed scouring treatment, with sodium citrate as a chelating agent, presents less aggressivity to the environment compared with the classical one. The temperature used was lower (55 °C), the pH close to the neutral point, and biodegradable chemicals were used. The chosen technology included a series of independent steps which they assumed: washing of flax/cotton fabric at 100 °C for dust and physically linked impurities removing, dried at room temperature, and conditioning at 105 °C in the oven for 2h. Afterward, the samples were immersed in the reaction bath which contained a mixture of pectinolytic products, the chelating agents (sodium citrate or EDTA), and the surfactant. The hydrolytic reaction was optimised following the influence of a pair of parameters: enzyme concentration/exposure time. Water samples from each reaction bath were collected and different physicochemical parameters were analysed: pH, salinity, TDS, conductivity, DO, CCOMn, turbidity and dry residue. The results obtained were following the legislation. In the case of the classical treatment, the data was up to 100 % higher compared with the new proposed treatment were complexing agent sodium citrate was used. Analysing from different points of view the results obtained, we can say that the considered treatment could be a promising alternative to the current one. It might contribute to less wastewater pollution and technological economical improvement.

Abstract: Alkaline treatment has a function to disrupt hydrogen bonding in network structure and to remove some hemicellulose, lignin and extractives for efficient contact with the matrix when preparing composites. Kelempayan (Neolamarkia cadamba) particles were treated using 0.5, 1 and 2% sodium hydroxide (NaOH) solution at a temperature of 90 °C for 60 minutes periods of immersion. The particles were washed with running tap water to neutralize excess NaOH and oven dried at 80 °C. The treated particles were then grounded to a fine size before being sieved to 60 mesh size of sawdust. Finally, the treated samples were air dried before chemical analysis. The sampling and preparation of sawdust were carried out according to the TAPPI Standard T257 cm - 02 (2002). The changes occurring on Kelempayan’s surface were assessed using Scanning Electron Microscopy (SEM). Chemical analysis indicated that hemicellulose, lignin and extractives became decreased by increasing alkaline concentration. Morphological analysis showed that treated surface was cleaner and rougher than that of untreated.

Abstract: Composite materials based on bio-derived furan resin and natural fiber as reinforcing elements were studied. The purpose of this research is to improve the mechanical properties of this composite material by focusing on the natural fiber treatment methods. Unidirectional flax fabric was pretreated by alkaline treatment, silane coupling treatment, and the combination between alkaline and silane treatment before impregnating with furan resin. Three-point bending test, SEM observation, and ATR-IR analysis were carried out to evaluate the effects of treatment methods on the composite samples. Results reveal that the flexural strength of the composite was increased to 215MPa, 232MPa, 247MPa for alkaline, silane, and alkaline-silane treated composites respectively while the flexural strength of the untreated composite sample is 200MPa. SEM images show the effects of alkaline treatment on a single flax fiber at different treatment durations. The coupling of silane on the surface of flax fiber was confirmed by ATR-IR.

Abstract: The present study deals with the one-step one-bath dyeing of with/without alkaline treatment of twill weaved 50/50 cotton/polyester blended fabric using disperse dyes only. The dyeing results are studied by colorimetric colour measurements, applying instrumental approach, and colour change during fastness tests. Several testing methods are designed and adapted to the disposable technical and material base. The results are found to be promising as an alternative dyeing technology and for effective product quality assessment.

Abstract: Currently, the use of technogenic raw materials, including wood waste is one of the trends in manufacturing of building materials. This is due to the limited resources, the need for long-distance transportation, the high material and energy cost of some technological processes of raw materials extraction and processing. All of them greatly hamper the development of the industry of building materials based on natural resources. Different cellulosic fillers of vegetable origin are used for the production of wood-cement compositions at the moment. Organic fillers along with the inherent valuable properties have a number of specific properties which have a significant effect on the processes of structure formation, structural-mechanical and construction properties of composites. The results of the research of the processes of water-soluble components removal from raw wood material are presented in the article. Processing of raw wood material was carried out in water and weak alkali solution in the research process. It is established that additional ultrasonic treatment considerably intensifies and increases the extraction of water-soluble sugars. The conducted research shows the possibility of improving the composite wood materials manufacturing technology with the aim of improving their performance without significant capital investments.