Effect Of Alkali Treatment Research Articles

Influence of Alkali Treatment and Fiber Content on Mechanical Properties of Pineapple Leaf Fiber (PALF)-Reinforced Cement-Based Composites via Full Factorial Design

In tropical regions such as the Philippines, pineapple leaf fiber (PALF) is abundantly available as a low-cost and renewable source for industrial purposes. In this research, PALF was used as a reinforcing material for cement-based composites to open up further possibilities in waste management. Since natural fibers are not fully compatible with the matrix due to their hydrophilic nature, surface treatment is necessary to enhance the fiber-matrix bonding. Fibers were treated using sodium hydroxide (NaOH) with varying concentrations (4%, 8% and 12%) for 6-hr immersion time at room temperature. PALF was then added at varying content (1%, 4% and 7% w/w cement) to the concrete mixture with a design mix ratio of 2:1 (sand: cement) and a constant water-cement ratio of 0.55. The samples were mechanically characterized after 28 curing days following ASTM C209 and ASTM C473. Full factorial experimental design (FFED) was used to investigate the effects of alkali treatment and the fiber content on the mechanical strengths of the composite. Experimental methods, analysis of variance (ANOVA) and normality test were carried out to evaluate, analyze and validate the results. The best results for tensile strength parallel to the surface and flexural strength at 2.028 MPa and 1.495 kN, respectively, were observed at composites with 1% PALF with 4% NaOH. Meanwhile, composites with 1% PALF with 12% NaOH showed the best result for tensile strength perpendicular to the surface at 1.681 MPa. According to ANOVA results, only the model for the tensile strength perpendicular to the surface showed a curvilinear behavior (p-value=0.012). Results revealed that the factor with the most significant effect was the interaction of the fiber content and alkali treatment on the tensile strength parallel to the surface (p-value=0.000), tensile strength perpendicular to the surface (p-value=0.001) and flexural strength (p-value=0.001).

Improvement of Mechanical Properties of Polylactic Acid/Oil Palm Fiber Composites by Alkali Treatment

The aim of this work is the improvement of mechanical properties of oil palm fiber (OPF) reinforced polylactic acid (PLA) composites by using sodium hydroxide (NaOH) treatment. NaOH concentrations (0 to 15 %wt.) and treatment times (0 to 30 min) were varied to determine the suitable condition for surface treatment of OPF. Aspect ratio (L/D) and the surface texture of OPF were investigated by using an optical microscope and scanning electron microscope (SEM), respectively. The result suggested that the most suitable condition for surface treatment of OPF was NaOH concentration of 10 %wt. at immersion time of 20 min. Aspect ratio and surface roughness of OPF increased after alkali treatment. For the effect of alkali treatment on the mechanical properties of the composite, it was evaluated by tensile and impact testings and SEM technique. The results showed that surface treatment with NaOH led to enhance mechanical properties of the composite due to improvement of interfacial adhesion.

Fused Deposition Modeling of Poly (lactic acid)/Nutshells Composite Filaments: Effect of Alkali Treatment

In this work, four kinds of nutshells (including walnut, almond, macadamia and wild almond shell powder (WSP, ASP, MSP and WASP) were composed with poly (lactic acid) (PLA). Fused deposition modeling technology was used to prepare the PLA/nutshell composite filaments. Nutshells were investigated by means of Fourier transform infrared spectroscopy regardless of the treatment with alkali. The composites were characterized by using: differential scanning calorimetry, thermogravametric, scanning electron microscopy. Meanwhile, the water-resistance and tensile properties were examined. The results showed that the thermal stability, water-resistant ability and tensile properties of untreated composites got worse comparing with that of PLA, but were enhanced dramatically after NaOH treatment. PLA/treated WASP has the highest degradation temperature. The crystallization degree of PLA/treated MSP and PLA/treated WASP was improved, when compared with that of PLA. The tensile strengths of PLA/MSP-Na and PLA/WASP-Na were almost close to that of PLA. PLA/MSP composite was the most water-resistant regardless of surface treatment. Those results indicated that the four kinds of composites have a potential application to manufacture structural parts with lighter weight.

Effect of alkali treatment of Salacca Zalacca fiber (SZF) on mechanical properties of HDPE composite reinforced with SZF

Advanced developments of design and structure industries require modern material which both complies with green environment issues to reduce non-renewable resources, and also has the prospect to be fundamental material. The aim of the research was to investigate the interaction between alkali treated of Salacca Zalacca Fiber (SZF) and High Density Polyethylene (HDPE) by using microscopic examination, chemical analysis, contact angle test, interfacial shear strength and flexural tests of composites. SZF was chemically treated using a 5% NaOH solution for 0, 1, 2,3, 4, and 5 h to modify the fiber's properties. Chemical analysis shows that hemicellulose was decomposed after alkalization-ray diffraction found that the crystalline index (CrI) was changed as a result of alkalization. Micrograph observations by scanning electron microscope (SEM) show the complete impurities removal and revealed the parallelly aligned cellulose microfibrils, while atomic force microscopy (AFM) result shows the decrease of surface roughness as seen in 2D roughness and 3D surface topography. Contact angle measurement was found that the contact angle decreases with increased treatment time which indicated the improvement on SZF wettability. From the IFSS test, it was found that the overall fiber-matrix adhesion of the composite was improved with peak adhesion obtained after 5-hour treatment.

Effect of alkali treatment on performance characterization of Ziziphus mauritiana fiber and its epoxy composites

This study aims to investigate the natural cellulosic fibers extracted from novel Ziziphus Mauritiana plants. The fibers were treated with alkali solution and epoxy composites were developed for both untreated and chemically modified fibers through hand lay-up process. Physico-chemical and thermomechanical characterization were carried for both untreated and alkali treated Ziziphus Mauritiana fibers through physical analysis, chemical analysis, Thermogravimetric analysis, Fourier transform infrared spectroscopy, X-Ray diffraction test and single fiber tensile test. The alkali treatment facilitates to remove amorphous constituents and improves the crystalline index by 1.31 times, thermal stability by 1.15 times and fiber strength by 1.44 times, which is supported by chemical analysis and Fourier transform infrared spectroscopy analysis. Later, developed Ziziphus Mauritiana composites were analyzed as per ASTM for its mechanical and sound absorption characteristics. The reduction in amorphous constituents after chemical treatment improved the surface roughness in alkali-treated Ziziphus Mauritiana fibers which influenced the bonding behavior. Also it improved the ultimate tensile strength by 2.12 times, flexural strength by 1.38 times and sound absorption coefficient by 1.15 times. Thus, the Ziziphus Mauritiana fibers are potentially suitable for use in lightweight structures.

Effect of alkali treatment on adhesion of thermoplastic polyurethane elastomer/polyester inter-ply hybrid composites

PurposeThe purpose of this paper is to investigate the effects of alkali treatment on adhesion of industrial thermoplastic polyurethane elastomer (TPU)/polyester woven fabric inter-ply hybrid composites.Design/methodology/approachInter-ply hybrid composites were exposed to varying concentration of sodium hydroxide at different temperature and time and their mechanical properties including differential scanning calorimetry, scanning electron microscope, tensile and peeling strength evaluated to determine optimal treatment parameters.FindingsModified polyester fabrics treated with alkali had higher tensile and peeling strengths. Accordingly, alkali treatment roughened the surface of polyester fabric, decreasing warp and weft densities, thus increasing fiber surface energy. The fabric had the highest peeling strength of 3.23 N/mm at treatment of 25% concentration of sodium hydroxide (NaOH). Short-term exposure to ultraviolet had little effect on interfacial adhesion of alkali-treated conveyor belt.Research limitations/implicationsPolyester fabric, applied in reinforcing industrial conveyor belts, is never degreased, roughened, sensitized or activated. In this paper, one-step treatment of polyester fabric was performed to increase its adhesion with polyester inter-ply hybrid composites, providing a reference for practical industrial application.Practical implicationsThe method developed in this research is simple and provides a solution to improving the interfacial adhesion of TPU/polyester conveyor belt.Originality/valueThe novel alkali treatment technology has many applications in the interfacial performance of composite materials.

Studies on Effect of Alkali Treatment on Mechanical Properties of Multi-Layer Viscose / Flax Composites

Composite fabrics consist of numerous structural components and are united into a single structure. The applications of composite fabrics are versatile and it is depending upon the constituent materials and the mechanical properties are changed by the constituents. The study of mechanical properties of composite fabrics such as flexural rigidity, tensile strength, impact became very essential to understand the suitability of application in various areas. In this study the various mechanical properties are studied by treating with alkali and resins. The results of mechanical properties were analyzed and compared with treated and untreated. The results show that alkali treated fabrics have enhanced mechanical properties.

Evolution of the pore and framework structure of NaY zeolite during alkali treatment and its effect on methanol oxidative carbonylation over a CuY catalyst

Alkali treatment is widely used on aluminosilicate zeolites with high Si/Al ratios in order to fabricate mesopores in the framework. However, for zeolites with low Si/Al ratios, the effect of alkali treatment on the pore and framework structure needed further study. In this work, Y zeolite is treated with NaOH solutions of different concentrations and is used as the support for Cu-based catalysts for oxidative carbonylation of methanol to dimethyl carbonate. The physicochemical properties of the supports and corresponding catalysts are characterized by N2 adsorption–desorption, X-ray diffraction, X-ray fluorescence, transmission electron microscopy, inductively coupled plasma mass spectrometry, X-ray photoelectron spectroscopy, and H2-temperature-programmed reduction analyses. The results show that no obvious mesopores are formed under alkali treatment, even at high NaOH concentration. However, amorphous species present in the micropores of Y zeolite are removed, which increases the micropore surface area as well as the crystallinity. Simultaneously, the cage structure is partially destroyed, which also leads to a slight increase of the pore volume and surface area. The altered micropore structure eventually increases the content and accessibility of the exchanged Cu species, which is beneficial to the catalytic activity. When the concentration of NaOH is 0.6 M, the space time yield of dimethyl carbonate for the corresponding catalyst was 151.4 mg g−1 h−1 which is 3.3-fold higher than that of the untreated-Y-zeolite-supported Cu catalyst. However, further increasing the alkali treatment strength can seriously destroy the basic aluminosilicate structure of the Y zeolite and decrease its intrinsic ion-exchange capacity. This results in the formation of agglomerated CuO on the catalyst surface, which was not conducive to catalytic activity.

SINTESIS DAN KARAKTERISASI KOMPOSIT FIBER SABUT KELAPA SAWIT DENGAN RESIN EPOKSI

The use of natural fiber as reinforcement for epoxy polymer composites is currently a concern for researchers because it is environmentally friendly so it can replace glass fiber or carbon in engineering applications. Palm fiber is a type of natural fiber that is produced by the cooking oil industry as a component of waste. The surface modification of fiber with NaOH solution is one of the factors that determines level of adhesion to the epoxy polymer matrix. This study to analyze the effect of alkali treatment on the morphology and characteristics of fiber. In addition, the effect of palm fiber composition on the mechanical properties of composites were studied. Alkali treatment on fiber was carried out using 10% wt sodium hidroxide solution. The morphology and characteristics palm fiber before and after alkali treatment were analyzed using SEM-EDX, XRD, and FTIR. Tensile tests were carried out on composites with treated fibers and without treatment with sodium hidroxide solution. The results showed that alkali treatment caused the surface morphology of the fiber to be finer due to the loss of lignin and hemicellulose components. Alkali treatment fiber can increase the tensile strenght. Composites with fiber and resin composition of 4%: 96% wt that have undergone alkali treatment have a maximum tensile strength of 21.60 MPa.

Alkali treatment of lignocellulosic fibers extracted from sugarcane bagasse: Composition, structure, properties

Lignocellulosic fibers extracted from sugarcane bagasse were treated with NaOH solutions of different concentration (0-40 wt%) to study the effect of alkali treatment on the composition, structure and properties of the fibers. Composition was determined by the van Soest method, structure was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), while mechanical properties by tensile testing. Hemicellulose and lignin content decrease, while cellulose content goes through a maximum as a function of alkali concentration. Crystallinity changes only slightly and microfibril angle (MFA) remains constant thus structural effects and especially MFA are not the primary reasons for changing properties. The Young's modulus of the fibers shows a slight maximum at around 2-4 wt% NaOH content, while tensile strength goes through a much more pronounced one at around 5-8 wt%. Direct correlation between structure and mechanical properties was not found indicating that composition is more important in the determination of properties than structure. Regression analysis proved that the combination of several compositional variables determines mechanical properties in a non-linear manner. The improvement in fiber properties was explained with the dissolution of weak amorphous fractions and the relative increase of cellulose content.

Effects of alkali treatment on the mechanical and thermal properties of sisal/cattail polyester commingled composites

Environmental and energy conservation pressure has led to a dramatic increase in the need for economically feasible lightweight materials that can be better substitutes for non-biodegradable materials in reinforced composites. In this study, the mechanical and thermal properties of polyester resin composites hybridized with a blend of untreated and alkali treated sisal (Agave sisalana) and cattail (Typha angustifolia) fibers were evaluated. Composites were fabricated by a hand lay-up technique at an optimal hybrid fiber weight fraction of 20 wt% and a constant sisal/cattail fiber blend ratio of 75/25. Flexural, tensile, compressive and impact strengths and moduli, as well as thermal conductivity of the composites, were evaluated following ASTM and ISO test methods. Analytical results indicated that alkali pre-treatment of the fibers enhanced the mechanical properties of the hybrid polyester composites though only marginal differences were recorded in the thermal conductivity of the composites fabricated with treated and untreated fiber blends. Morphological examination revealed that the major failure modes were fiber pull-outs and fiber fracture in composites fabricated with untreated and treated fiber blends, respectively. The composites produced could find non-structural applications as ceiling boards, electronic and food packaging materials but their properties such as wettability, crystallinity, flammability and other thermal properties need to be further investigated.

Effect of Alkali Treatment of Nettle Fibers on Oil Absorbency

ABSTRACT Nettle is a cellulosic plant fiber with a reasonably large lumen and they are a cheap, easily renewable source of fibers with the potential for oil absorbency. To the author’s best knowledge, there are no published data available on the oil absorbency behavior of alkali-treated nettle fibers. In this work, alkali treatment on nettle fibers was carried out with a view to improve their oil absorbency. The effects of treatment time, temperature, concentration, and solid: liquor ratio of nettle fibers on oil absorbency was assessed. As compared to raw nettle fibers, the oil absorbency of alkali-treated nettle fibers was considerably higher. Nettle fibers were also characterized by FTIR, TGA, SEM, and reusability tests. Oil absorbency capacity of alkali-treated nettle fibers has also been compared with other natural materials.

Effect of Alkali Treatment on Photovoltaic Performances of Cu(In,Ga)(S,Se)2 Solar Cells and Their Absorber Quality Analyzed by Urbach Energy and Carrier Recombination Rates

Cd-free Cu(In,Ga)(S,Se)2 (CIGSSe) solar cells are fabricated by all-dry process, where CIGSSe absorbers with and without alkali (K and Cs) treatments are used. Urbach energy (EU) is estimated in long-wavelength edge of external quantum efficiency. It is revealed that reduced EU through K and Cs treatments yields decreased open-circuit voltage deficit. Carrier recombination rates across devices are reduced through K and Cs treatments, corresponding to increased carrier lifetimes and decreased EU. Conversion efficiency of Cd-free CIGSSe solar cells with a structure of glass/Mo/CIGSSe/Zn0.8Mg0.2O/Zn0.9Mg0.1O:Al is enhanced from about 17.8% (none alkali) to 18.5% (with K) and to 20.3% (with Cs).

Thermogravimetry and Interfacial Characterization of Alkaline Treated Cantala fiber/Microcrystalline Cellulose-Composite

The effects of alkali treatment on morphology, thermal stability, and interfacial shear strength of cantala fiber (CF) were investigated. CF untreated and treated with 6% sodium hydroxide (NaOH) for soaking times 3 h, 6 h, 9 h, 12 h, and 15 h. The results of untreated and treated fibers were observed by the Scanning Electron Microscope (SEM). The results of scanning electron microscopy on the CF surface showed cleaner fibers and increased surface roughness by alkali treatment. Alkali treatment has changed the characteristics of the fiber surface topography as seen in the SEM results. CF with soaking over 6 h occurs of damage to the fibrils and fiber structure. Prolonged treatment results in poor fiber quality. Thermogravimetric analysis (TGA) is used to measure the amount and rate of change in CF weight that is not treated and treated. The results of the study show that alkaline treatment improves most of the fiber’s properties. The thermal stability of treated CF is higher than that of untreated. Interface shear strength tests show that fiber with 6% treatment, and 6 h soaking, gives the most upper strength of 3.67 MPa, an increase of 47.39% if compared before treatment. Flexural strength and modulus of elasticity were increased with alkali treatment and the addition of microcrystalline cellulose.

Alkali Treatment Effect on the Tensile and Impact Properties of Recycled High-Density Polyethylene Composites Reinforced with Short Cantala Fiber

In this study, an environmentally friendly composite was prepared from cantala fiber and recycled high-density polyethylene. Alkali treatment was utilized to improve the fiber–matrix interface of cantala fiber. The alkali treatment was carried out with a 2% NaOH solution for periods of 0, 4, 8, 12, 16, 20, and 24 hours. Various recycled high-density polyethylene composites reinforced with treated and untreated short cantala fiber were produced by hot press. The tensile and impact properties of the composites were examined to reveal the effect of alkali treatment. Changes in fiber–matrix bonding were investigated via composite fractography using scanning electron microscopy. A study of fiber morphology and other supporting tests, such as the fiber tensile test, X-ray diffraction, and Fourier transform infrared microscopy were also carried out. The results show that the addition of alkali-treated fiber to recycled high-density polyethylene composites enhanced the composites’ tensile and impact performance: Tensile strength improved by 15.5% and impact strength by 24.8%.

Alkali treatment of bamboo powder mixed polypropylene and its effect on properties

Bamboo powder (BP) was treated with different concentrations of alkali solution, and modified polypropylene material of bamboo powder/polypropylene blend was prepared. Using the scanning electron microscopy (SEM) and X-ray diffractometry (XRD) to study the effects of alkali treatment and various alkali concentrations on the micro-structure and mechanical properties of the modified polypropylene. The test results illustrate that the alkali treatment can remove the amorphous cement between lignocellulose, form more fine mesh structure, and increase the surface area, which is beneficial to improve the mechanical interlock between the fiber and the polymer matrix. Thus, improving the mechanics performance of composites by this method. As the increase of alkali solution concentration, the impact strength of bamboo powder/polypropylene composites show the trend of rising up and then descending. When the concentration of sodium hydroxide is 3%, the bamboo powder/polypropylene composite material has better normal temperature impact strength. When the sodium hydroxide concentration is 9%, the bamboo powder/polypropylene composite has the optimal yield strength.

PSVII-7 Effects of alkali treatment on nutrient content and ergot alkaloid concentration in tall fescue silage

Abstract Addition of alkaline compounds at harvest may affect in vitro digestion and ergot alkaloid concentrations in endophyte-infected tall fescue silage. Silage (n = 60; 10 replications/treatment) was produced by filling vacuum-sealing plastic bags (35.5 cm by 27.9 cm) with 150 g of K31 tall fescue (DM basis; forage DM=76.9%; 96% endophyte infection rate) harvested in June. Alkalizing agents (CaO and NaOH) were solubilized in water (20% inclusion; wt/wt basis) and added to the forage at inclusion rates of 0%, 1%, 2%, 3%, 4%, and 5% on a dry matter basis. After ensiling for 42 d, forage samples were lyophilized and subsampled for proximate analysis and analysis of ergot alkaloids. A separate subsample was taken for in vitro total disappearance determination, and each sample was replicated in triplicate. Forage quality and digestibility values were calculated on an organic matter basis because organic matter linearly decreased (P < 0.01) as alkali increased. Alkali increased pH linearly (P < 0.01). Forage NDF decreased linearly (P < 0.01) as greater amounts of alkali treatment were included. Crude protein did not differ (P = 0.41) among treatments. In vitro total disappearance (OM basis) increased linearly (P < 0.01) as inclusion of alkali increased. Total ergot alkaloid concentration did not differ (P = 0.62) across treatments. Ergovaline concentration increased linearly (P < 0.01) with increasing alkali inclusion, but remained below established threshold for toxicity in ruminants. Lactic acid concentration responded quadratically (P < 0.01) with the lowest value corresponding to 3% alkali treatment. Acetic acid concentration increased quadratically (P < 0.01) with the highest value occurring during the 1% alkali inclusion. Propionic acid concentration increased linearly (P = 0.02) as alkali inclusion increased. A quadratic effect (P < 0.01) was observed for butyric acid concentration, with a decrease in butyrate above 1% alkali inclusion. Under conditions of this experiment, addition of alkalizing agents increased digestibility of baled tall fescue silage.

Effect of alkali treatment on single species wood pulp fiber properties for the application of nursing pad absorbent core

Effect of alkali treatment on single species wood pulp fiber properties for the application of nursing pad absorbent core

Alkali-treated cellulose carrier enhancing denitrification in membrane bioreactor

The performance of hybrid MBRs and the improvement of denitrification with the addition of alkali-treated cellulose as microbial carrier and carbon source were investigated in this study. Three kinds of natural celluloses were evaluated by batch experiments. Straw was selected to construct a hybrid MBR. Results showed that the effect of alkali treatment on the accessibility of carbon source was obvious, the COD release capacity of the three carriers increased from 136–178 mg g−1 to 250–323 mg g−1, and the denitrification potential increased from 112.04–157.94 mg g−1 to 233.82–250.69 mg g−1 as compared with the untreated groups. All MBRs achieved high COD and NH4+-N removal irrespective of rice straw addition or not. However, the denitrification rate was enhanced effectively by adding straw. TN removal in the straw group and alkali-treated straw group increased to 49.83% and 63.46% respectively as compared with the control group of 28.80%. Nitrate saturation constant (KNO) of the control group, straw group and alkali-treated straw group MBRs were 1.82, 0.43, 0.21 mg NO3−-N L−1, respectively. The KNO of alkali-treated straw group MBR was the lowest one, which is the closest to the single-stage denitrified KNO. Addition of cellulose carrier can improve simultaneous nitrification and denitrification (SND) due to the presence of dissolved oxygen gradient in hybrid MBRs. More significantly, alkaline pretreatment increased the cellulose solid carbon source bioavailability and enhanced the function of microbial carrier thereby accelerating SND effectively.

The Effect of Alkali Treatment on Chemical and Physical Properties of Ichu and Cabuya Fibers

ABSTRACT Ichu and Cabuya were characterized and the effect of alkali treatment on the chemical and physical properties of these fibers was studied. This treatment was carried out to remove non-cellulosic components in order to improve the adhesion of these fibers to be used as reinforcing composites since they are currently being tested in polymer matrix composites. The chemical properties were investigated through TAPPI Standards and FTIR spectroscopy. The physical properties (microfibrillar angle and density) were analyzed through polarized light microscopy and a gas pycnometer, respectively. The results show that with this chemical treatment, it is possible to remove 53.9% of lignin and 22.7% of hemicellulose for Ichu fiber and 50.7% and 91.7%, respectively, for Cabuya. Besides, it was found that the microfibrillar angle is not affected by this chemical treatment since its effect is only superficial. In addition, SEM images show that Ichu fiber has amorphous silica particles in its surface, in which it becomes a potential fiber for cement composites.