Alkaline Treatment Process Research Articles

Polyacrylamide/Cellulose Nanofibers Composite As Quasi Solid Electrolyte for Rechargeable Zinc-Ion-Battery

This research aims to optimize the cellulose nanofiber content in polyacrylamide (PAM) using as quasi-solid electrolyte composites for zinc-ion batteries (ZIBs). The cellulose nanofibers (CNFs) derived from hemp were prepared via alkaline treatment and bleaching process, followed by mechanical defibrillation. The chemical functional group analysis confirmed the successful extraction of lignin and cellulose from hemp fiber. The improved thermal stability of cellulose nanofibers indicated the success of the chemical treatment in removing non-cellulosic components. Furthermore, quasi-solid electrolyte composites of PAM / CNFs at 0.25, 0.5, 0.75, and 1 wt.% of cellulose nanofibers were prepared. At 1 wt.% CNFs addition, PAM / CNFs composites showed the highest values for electrolyte uptake, and electrochemical impedance spectroscopy with the highest ion conductivity of 59.6 mS cm-1. For the plating/stripping testing with symmetrical zinc cell, PAM / CNFs at 1.0 %wt CNF also demonstrated the lowest overpotential with the best zinc dendrite suppression feature. For zinc-ion battery performance test, the quasi-solid electrolyte composites of PAM / CNFs at 1.0 %wt CNF were fabricated and employed with electrochemical properties testing, including cyclic voltammetry, galvanostatic charge-discharge, electrochemical impedance spectroscopy, and cycle stability. This optimized quasi-solid electrolyte composites reached the highest specific capacity of 134.2 mA g-1 at a current density of 0.1 A g-1 and maintained capacity retention of 90.8% of initial capacity with 94.4% coulombic efficiency after 500 cycles.

Modeling and Optimizing the Alkaline Treatment Process to Enhance the Date Palm Fibers’ Tensile Mechanical Properties Using RSM

ABSTRACT This study aims to enhance the mechanical properties of date palm fibers (DPFs) by implementing a targeted treatment technique. The response surface methodology (RSM) is utilized for modeling and optimizing. The study seeks to identify the optimal Alkaline treatment settings for improving the mechanical properties of DPFs by carefully analyzing parameters such as average diameter, time, and NaOH concentration. The analytical results offer valuable insights into the possible use of DPFs in many engineering applications, contributing to the industrial advancement of sustainable and eco-friendly materials. The experimental findings are analyzed using a full-factorial design (43), incorporating analysis of variance and RSM. Combining RSM and desirability function is used to get the best mechanical properties, including stress, strain, and Young’s modulus. The model appropriateness is evaluated by analyzing residual values. The findings suggest that the sodium hydroxide concentration (%NaOH) has the most significant impact on strain (11.63%), stress (12%), and Young’s modulus (11.72%) besides the time t (h) also significantly influences 6.01%, 6.26%, and 5.79% strain, stress, and Young’s modulus, respectively.

Effects of alkaline treatment and manufacturing process on mechanical and absorption properties of Wild Abyssinia Banana fiber reinforced epoxy composite

To enhance the properties of natural fiber composite, proper selection of an optimum alkaline concentration for fiber surface modifications and composite manufacturing techniques are the main criteria to be considered. This study examined how NaOH and manufacturing methodsaffect the mechanical and absorbency characteristics of a Wild Abyssinia Banana (WAB) epoxy composite. 2 %, 5 %, and 7 % (w/v) NaOH concentrations; hand-layup and hydraulic press manufacturing techniques have been considered. Petroleum, diesel, distilled, and artificial lake water (wastewater) were used for the absorption test. A 5 % NaOH treatment improves composite tensile, flexural, and impact strengths by 14.78 %, 8.59 %, and 29.63 %, respectively. Moreover, the 5 % NaOH treatment reduced the absorption rate of the WAB fiber composite. Hydraulic press manufactured untreated WAB fiber composite was observed to have 26.27 % and 13.45 % higher tensile and flexural strengths than hand layup. The treated WAB fiber-reinforced composite can be utilized in gas stations, home appliances, and finishing materials for construction applications.

Extraction of cellulose nanocrystalline from Camellia oleifera Abel waste shell: Study of critical processes, properties and enhanced emulsion performance

Cellulose nanocrystals (CNCs) extracted from the waste shell of Camellia oleifera Abel (C. oleifera) are gaining attention as valuable materials. In this study, CNCs were extracted from the agricultural waste shell of C. oleifera through phosphoric acid and sulfuric acid hydrolysis, respectively. Firstly, we optimized the alkaline treatment process for cellulose isolation by using response surface methodology. Furthermore, the properties of CNCs were investigated by neutralizing them with NaOH and NH3·H2O, and by dialysis in water. In addition, the characterization methods including FT-IR, TGA, AFM and TEM were used to analysis the properties of the synthesized CNCs. Finally, CNCs were studied for their application in essential oil-based Pickering emulsions. CNCs obtained from sulfuric acid showed the smallest particle size and good dispersibility. Moreover, the release profiles of essential oils in the emulsions were followed by Peppa's kinetic release model. The antibacterial activity of the emulsions against E. coli and S. aureus showed that CNCs-stabilized emulsions enhanced the antibacterial activity of essential oils. Therefore, neutralization treatments may enhance the properties of CNCs, and CNCs stabilized Pickering emulsions can enhance antibacterial activity of essential oil. This study provides insight into the potential application of CNCs derived from C. oleifera waste shells.

Characterization of Cellulose Fiber Derived from Hemp and Polyvinyl Alcohol-Based Composite Hydrogel as a Scaffold Material.

Cellulose nanocrystals (CNCs) were successfully extracted and purified from hemp using an alkaline treatment and bleaching process and subsequently used in conjunction with polyvinyl alcohol to form a composite hydrogel. Cellulose nanocrystals (1-10% (w/v)) were integrated into polyvinyl alcohol, and sodium tetraborate (borax) was employed as a crosslinking agent. Due to the small number of cellulose nanocrystals, no significant peak change was observed in the FT-IR spectra compared to pristine polyvinyl alcohol. The porosity was created upon the removal of the water molecules, and the material was thermally stable up to 200 °C. With the presence of cellulose nanocrystals, the melting temperature was slightly shifted to a higher temperature, while the glass transition temperature remained practically unchanged. The swelling behavior was examined for 180 min in deionized water and PBS solution (pH 7.4) at 37 °C. The degree of swelling of the composite with cellulose nanocrystals was found to be higher than that of pristine PVA hydrogel. The cell viability (%) of the prepared hydrogel with different proportions of cellulose nanocrystals was higher than that of pristine PVA hydrogel. Based on the results, the prepared composite hydrogels from cellulose nanocrystals extracted from hemp and polyvinyl alcohol were revealed to be an excellent candidate for scaffold material for medical usage.

Thermal and morphological characterization of biowaste date palm fiber‐reinforced polybenzoxazine and epoxy composites

AbstractWaste date palm fiber (DPF) has recently emerged as a promising natural fiber due to its abundance, renewability, and low cost. The study discussed the use of DPF as reinforcement in composites, particularly in polybenzoxazine (PBz), epoxy resin (EP), and their copolymer (EP‐co‐PBz) composites. The waste DPF underwent an alkaline treatment process, resulting in a high‐performance material that exhibits exceptional interaction with the matrix. The composite samples were fabricated using 5–20 wt% of alkali treated DPFs with polybenzoxazines and epoxy resins. The study examined the thermal and morphological properties of the resulting composites and found that they exhibited remarkable enhancements in various properties. For instance, the PNaphz‐COOH reinforced 5 wt% DPFs composite showed a significant increase in Td5% and Td10%, while the EP‐co‐PBz reinforced DPFs composites exhibited a remarkable increase in char yield (Yc). The SEM analysis of the composite surface further validated these findings, highlighting the remarkable interfacial bonding between the DPFs and the matrix. The remarkable enhancements in thermal properties demonstrated in this study open up new possibilities for utilizing waste DPF in various applications.Highlights Waste date palm fiber enhances thermosetting polymer reinforcement for high‐performance composites. Alkaline treatment improves interfacial bonding between waste DPF and matrix. Composites reinforced with waste DPF exhibit outstanding thermal and morphological properties.

Extraction and characterization of novel cellulose nanocrystals from Artemisia scoparia straw and their application in hydroxypropyl methyl cellulose (HPMC) films

Abstract This research study reports on the extraction of nanocellulose followed by structural and thermal analysis and application of nanocellulose in hydroxypropyl methyl cellulose (HPMC) nanocomposite films. The cellulose nanocrystals were isolated from Artemisia scoparia straw through an alkaline treatment and bleaching process, followed by sulphuric acid hydrolysis. The HPMC nanocomposite films were prepared by a solution casting method and dried at room temperature. Fourier transform infrared-ray (FTIR) spectroscopy and thermogravimetric analysis (TGA) techniques were used to analyze the structural and thermal properties of the materials, including the cellulosic material, the nanomaterial, and the nanocomposites. The FTIR spectra indicated that the extraction procedure was adequate, demonstrating the removal of lignin and hemicellulose and the preparation of nanocellulose. The TGA results revealed the thermal degradation pattern of the cellulose and showed that the HPMC films had enhanced thermal stability. This research demonstrates that A. scoparia straw has potential for the extraction of cellulosic nanomaterial and a wide range of applications in nanocomposites.

Utilization of surface-active compounds derived from biosolids to remediate polycyclic aromatic hydrocarbons contaminated sediment soil

In the present study, surface-active compounds (SAC) were extracted from biosolids using an alkaline treatment process. They were tested for their remediation efficiency of crude oil-contaminated sediment soil and was compared with Triton x-100. The SAC exhibited a similar soil washing efficiency to that of the commercial Triton x-100, and under the optimized soil washing parameters, SAC exhibited a maximum of 91% total polycyclic aromatic hydrocarbons removal. Further, on analysing the toxicity of the soil residue after washing, it was observed that SAC from biosolids washed soil exhibited an average of 1.5-fold lesser toxicity compared to that of Triton x-100 on different test models-earthworm, a monocot, and dicot plants. The analysis of the key soil parameters revealed that the commercial surfactant reduced the soil organic matter and porosity by an average of 1.3-fold compared to SAC. Further, the ability of surfactants to induce toxicity was confirmed by the adsorption of the surfactants on the surface of the soil particles which was in the order of Triton x-100 > SAC. Thus, this study suggests that SAC can be applied as an effective bioremediation approach for contaminated soil for a greener and sustainable ecosystem.

The Design and Characterization of a Strong Bio-Ink for Meniscus Regeneration.

The meniscus is vital to the mechanical function of the knee, while it is frequently harmed because it bears a heavy load. A strong bio-ink for meniscus regeneration was prepared for the future meniscal tissue engineering. The prepared bio-ink consists of poly (vinyl alcohol) and decellularized extracellular matrix (PVA/dECM). The mechanical properties and the rheological features were explored to evaluate the effects of freezing/thawing cycles and alkaline treatment process. The printability was verified using a three-dimensional printer. The endothelial cells were employed to assess the biocompatibility. Finally, a 12-week rabbit meniscus defect model was established to evaluate the meniscus regeneration capability. We found that the bio-ink by soaking in alkaline for 40 min and 20 freezing/thawing cycles demonstrated excellent mechanical properties. The Young's modulus reached 0.49 MPa and the stress limitation was 2.9 MPa. The results also showed good printability and biocompatibility of the proposed bio-ink in vitro. The PVA/dECM hydrogel healed the meniscus defect after 12 weeks of implantation. The articular cartilage and subchondral bone exhibited normal microstructure and composition. These results suggested that the PVA/dECM hydrogel could be a promising solution to repair meniscal lesions with preventive effects against degenerative meniscal tears and post-traumatic arthritis.

New insights into improved electrochemical performance of graphene synthesized from rice husk doped graphite composite electrode for supercapacitor

Graphene was synthesized from rice husks by the alkaline treatment process, which was used as a dopant to produce graphite: graphene composite electrodes for supercapocitor application. The composite electrode material was characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDX), and Fourier Transform Infrared Spectroscopy (FTIR), Cyclic Voltammetry (CV), and Electrochemical Impedance Spectroscopy (EIS). At 5 mV/s, the graphite (G) and graphene (Gr) ratio of G0.3 gGr0.15 g produced the highest specific capacitance of 16,007.02Fg–1. Electrochemical impedance spectroscopy (EIS) revealed the low resistance property of the prepared electrode samples. The results show that the graphene derived from rice husk doped graphite electrode material has great potential for supercapacitor electrodes because of its low cost and excellent electrochemical performance, thus possessing great potential in future energy development.

Optimization and Modeling of Sound-Absorption Properties of Natural Fibers for Acoustical Application

ABSTRACT Kenaf fibers have long been utilized because of their remarkable properties, such as availability, durability, and strength. Recently, they have also been used as sound-absorbing composites for noise control purposes. This paper investigates the possibility of improving the tensile strength of kenaf fibers through optimizing the alkaline treatment process. It also considers the effects of such optimization on the acoustic absorption coefficients of the samples fabricated from these treated kenaf fibers as well as the applicability of the numerical model to predict the acoustic absorption. Having employed the response surface methodology (RSM) to optimize the alkaline treatment process and achieve optimal conditions for the kenaf fibers, the scanning electron microscopy (SEM) and tensile test were used to study and compare the morphological and tensile properties of raw fibers (nonoptimal) and the fibers treated in optimal conditions. Several cylindrical samples with constant thickness and density (30 mm and 200 kg/m3) were then made of fibers treated in optimal conditions. The sound absorption coefficient, porosity, and airflow resistivity of these samples were measured based using ISO 10534–2 (impedance tube system), SEM and ASTM C423-09A, respectively. The results demonstrated that the tensile strength of optimally treated fibers increased by 182.39%. The acoustic absorption coefficients of the samples fabricated from these fibers were also higher at all frequencies (low-, mid-, and high-frequency range) compared with samples made of untreated fibers in a way that the Sound Absorption Average value of the former increased by 17.97%. Moreover, it was found that inverted Dunn and Davern model via Nelder-Mead simplex method well follows the sound absorption pattern from the experimental results in the overall frequency range. The use of multifaceted improvement approaches for natural materials such as kenaf fibers increases the usability of these materials as sustainable and eco-friendly alternatives in the engineering process of manufacturing sound-absorbing materials.

Biochemical Characterization of Orthosiphon Aristatus and Evaluation of Pharmacological Activities

ABSTRACT This study investigated the phytochemicals, protein and cellulose profiles, and the antiradical, antibacterial and cytotoxicity activities of Orthosiphon aristatus. The cellulose profile of the herb had functional groups of C-H and C-O stretching, C = O ester, CH2 bending and scissoring using alkaline treatment and bleaching process. Rosmarinic acid was the most dominant compound in the plant extract and its fractions prepared from reflux extraction followed by column chromatography for sample clean-up. At least 8 protein bands could be seen from the polyacrylamide gel and transketolase with the molecular size, 73 kDa was identified. The antiradical activity of the protein fraction increased after trypsin hydrolysis. The antiradical activities of crude extract and fraction 2 achieved up to 90% inhibition at 80 and 40 µg mL−1, respectively. Fractionation increased the rosmarinic acid concentration, thus increasing the antioxidant capacity of fraction. Rosmarinic acid was the main contributor inhibiting the growth of Pseudomonas aeruginosa. Both crude extract and its fraction were non-cytotoxic as the 50% cell viability was 565.6 and 150.5 µg mL−1, respectively, using human fibroblasts.

Effect of NaOH Concentration in Alkaline Treatment Process for Producing Nano Crystal Cellulose-Based Biosorbent for Methylene Blue

The development of textile industry in Indonesia has been increasing rapidly. The vast and continuous development of the textile industry results in an evitable increase of wastewater. One of the wastewater ingredients that difficult to be treated is dye. Dye is a pollutant with complex aromatic structure that is difficult to degrade. There are many dyes could be used, however, methylene blue is mostly used. To treat MB, several treatment methods are available. Among the methods, adsorption has been widely applied, due to its simplicity and effectiveness. In this research, nano crystal cellulose (NCC), which has a large surface area dan better mechanical properties, was prepared from the oil palm trunk and it was proposed to adsorb the methylene blue. Briefly, the process of making NCC as a biosorbent consists of the raw material pretreatment, alkaline treatment, bleaching, hydrolysis, and sonication steps. Alkaline treatment plays an important role for extracting hemicellulose, lignin and other extractive substances, so that NCC is expected to have high cellulose purity. The alkaline treatment was conducted by extraction methode using NaOH at 80 °C for 2 hours. The result showed that the percent of removal of hemicellulose dan lignin were 50.0, 55.6, and 51.73 % for NaOH concentration of 3, 4, and 5 % (w/v) respectively. This result was also supported by the result of FTIR spectra analysis on each corresponding sample. Based on these data, it can be confirmed that the optimum NaOH concentration for alkaline treatment of oil palm trunk is 4 % (w/v). Furthermore, adsorption test of NCC using methylene blue solution gave percent removal of methylene blue in the range of 69.46-72.51%.

Effect of Chelating Agents on Removal of Heavy Metal Cations of Cellulose-based Ion Exchange Resins from Water Hyacinth

Presently, heavy metal pollution in natural water resources is considered very hazardous. The purpose of this research is to develop the novel cellulose-based ion exchange resins from water hyacinth and the effect of chelating agents on the removal of heavy metal cations from single-metal aqueous solutions has been investigated. Cellulose was prepared from the stem of water hyacinth by alkaline treatment process then cellulose-based ion exchange resins were prepared via esterification reaction between cellulose with two different chelating agents such as pyromellitic dianhydride and 3,3’,4,4’- benzophenone tetracarboxylic dianhydride. The chemical structure, crystallinity index, surface morphology, and thermal stability of resins were characterized and analyzed with FTIR, XRD, SEM, and TGA, respectively. The results confirmed the esterification reaction between anhydride groups of chelating agents with hydroxyl groups of celluloses due to the apparent peak of the ester group. Heavy metal cations adsorptions were studied in optimum conditions and the residual concentration of heavy metal cations was measured by ICP. These resins showed high adsorption capacities of more than 98 mg/g for Pb2+, Cd2+, Cu2+, and Ni2+. Moreover, the adsorption process was controlled by the ion exchange mechanism. Therefore, the novel cellulose-based ion exchange resins could be suitable for the removal of pollutants from wastewater.

Hydrothermal Synthesis of Multi-Color Fluorescent Carbon Dots from Sappan Wood (Caesalpinia sappan) as an Acid-Base Indicator

Caesalpinia sappan L., known as sappan wood, has been extensively explored by many researchers because it contains various structural types of phenolic compounds. This study objectives are to investigate the effect of pH on the flourescent color of carbon dots (CDs) from sappan wood and its application as an acid-base indicator under UV light for the first time. CDs were synthesized through the hydrothermal route in ethanol solvents. The synthesized CDs were further characterized by UV-Vis spectrophotometry, fluorescence and Fourier Transform Infrared (FT-IR) spectroscopy. Based on the results, CD solutions performed multiple flourescent colors (yellow, orange and green) under UV light at 365 nm when the pH was adjusted to be 1, 3, 5, 7, 9 and 11. These multiple colors were produced because of the instability of phenolic compounds in the sample, especially brazilin which was easily oxidized to brazilein in alkaline condition. According to the FT-IR spectra, the most prominent differences of the sample before and after the treatment process was observed in the peak region ranging from 1500-1700 cm-1. The characteristic band of carbonyl groups was identified at 1697 cm-1 in the treated sample (pH 9), but it was unobserved in the spectrum of sappan wood and the treated sample (pH 5). The presence of carbonyl group can be assumed that brazilin has been oxidized to brazilein after the alkaline treatment process and making the flourescent color was gradually shifted from yellow to green. Under normal light, the sappan wood�s extract and CD solution produced yellow and red colors in acidic and alkaline conditions, respectively. However, only CD solutions which have yellow, orange and green emissions in different pH conditions under UV light. Therefore, the synthesized CDs can be used as an acid-base indicator in both different light conditions.

Effect of self-treatment process on properties of natural fiber-reinforced geopolymer composites

ABSTRACT Natural (hemp) fibers can be used in the cementitious composite as they have superb engineering properties, e.g. environmentally friendly and offer economic advantages. However, alkaline treatment (alkalization) process of natural fiber prior to mixing is required to modify fiber surface, making fibers more adhesive and compatible with cement paste. Geopolymer, one of the green alternative cementitious materials, is fortuitously involved in the alkaline environment, as alkaline solutions are used as its activators. The latent benefit, regarding the influence of alkalinity in geopolymer systems, namely ‘self-treatment process’ was thus investigated. The self-treatment process is a ‘Just-adding’ of as-received hemp fibers into geopolymer mixture without any pre-alkaline treatments. The results showed that the self-treatment process was governed by the alkaline environment in the geopolymer system and alternatively acted as an alkaline treatment condition for natural fibers, indicated by SEM and FT-IR analysis. The pre-alkalization process can be skipped in the self-treatment approach with similar mechanical properties to the ordinary processes. The main findings of this work could be further tailored to partially or fully the conventional alkaline treatment process and provide an opportunity for any other natural fiber geopolymer composites to be easily utilized in massive amount and used in practical applications.

INFLUENCE OF CHEMICAL SURFACE MODIFICATION ON MICRO-WEAR CHARACTERISTICS OF SUGARCANE NANOCELLULOSE EPOXY NANOCOMPOSITES

The waste sugarcane bagasse is the primary agricultural biomass of sugarcane industry and its main constituents is cellulose. These waste sugarcane bagasse can also be applied as reinforcement material in polymer matrix composites. In this present work, the nanocellulose fibers extracted from sugarcane bagasse using salt solution and alkaline treatment process. Sugarcane nanocellulose fiber reinforced epoxy nanocomposites were manufactured by wet layup method. This investigation has been conducted to exhibit the utilization of plant cellulose fiber as the potential reinforcement of synthetic fibers in tribo-composites. The dry sliding wear experiments designed and carried out as per central composite design to determine influence of 3 variable factors such as sliding velocity, sliding distance and load on the wear characteristics of epoxy nanocomposites. From ANOVA (Analysis of variance), it is observed that all three independent parameters plays an important role in the wear characteristics of epoxy nanocomposites, as proven from scanning electron microscope. Simultaneously minimize these tribological characteristics, desirable values of the parameters were depicted to be 5.94 m/s, 5 km and 5 N for sliding velocity, distance and load respectively. From normal probability curves, it is signified that there is a good agreement within the RSM models and experimental results.

Properties of PP Wood-Plastic Composites with Biocompatibility Additives

Maleic anhydride grafted polypropylene compatibilizer (MAPP) and chitosan (CS) were mixed and used as a compound coupling agent to modify the PP matrix. 5 wt% NaOH and 10 wt% NaOH aqueous solution were used to treat corn stalk fiber (CSF), respectively. The effect of the complex coupling agent and the alkali treatment on the mechanical properties of CSF/PP composite was investigated. Morphological observation of the fracture surfaces was accepted to confirm CSF dispersion and wetting with the help of SEM. The results of the water absorption further demonstrated the binding of the interface between the CSF and the PP matrix. The wetting of the CSF in the PP was improved with the addition of the complex compatibilizer (5% MAPP + 5% CS). The formation of chemical bonding between the fiber and the matrix resulted in enhancing the interfacial compatibility between them. Compared with the pure PP, the flexural strength of 15-UT-5MAPPCS (63.14 MPa) and 15-UT-5MAPPCS (69.35 MPa) increased by 22.5% and 34.5%, respectively. The complex compatibilizer can replace alkaline treatment process to improve the mechanical properties of the composite.

Enhancing the dimethyl ether carbonylation performance over mordenite catalysts by simple alkaline treatment

In this paper, post-synthesis modified MOR catalysts were prepared by alkaline treatment with and without the presence of templates. To investigate the modification effect of alkaline treatment to the structure and acid sites, the obtained catalysts were characterized by XRD, N2 adsorption-desorption, SEM, 29Si NMR, 27Al NMR, NH3-TPD and FTIR. The characterization results showed that the crystallinity of all samples decreased while specific surface area and pore volume increased to some extent. Certain amount of Si species and fewer amount of Al species were removed out during the alkaline treatment process, thus leading to the formation of mesopores and macropores. The protective effect of templates to the strong acid sites in the 8 MR and micropores were remarkable. Without the presence of templates, part of the micropores would be destroyed and the strong acid sites would largely be removed. Over the samples that had been alkaline modified with templates inside the micropores, the carbonylation performance still remained the same and the single-pass lifespan gradually extended due to the enhanced mass transfer efficiency and decreased acid sites in the diffusion paths. The side reactions were largely inhibited and the amount of coke deposition also decreased, which demonstrated that retaining the templates during the alkaline treatment was an effective way to enhance the DME carbonylation performance and suppress the coke deposition during the carbonylation process at the same time.

Studies on degradation performance of Mg-4.0Zn-1.5Sr alloy with coated of the laser surface processing combining alkaline treatment

The surface modification of biomaterial Mg-4.0Zn-1.5Sr alloy has been done by means of laser surface processing combining alkaline treatment process, as well as the degradation performance of Mg-4.0Zn-1.5Sr alloy with and without coatings in Hank’s solution has been analyzed comparatively. The results indicate that the optimal parameters of laser surface processing are that the power is 3 kW, the current 200 A, the width 1mm, the defocus amount 135 mm and the scanning speed 1mm/s. The optimal parameters of alkaline treatment are that the solution is NaOH, the concentration 0.5 mol/L, the temperature 80 °C and the time 12 h. There are only two phases of Mg (OH)2 and magnesium matrix, and the surface generated most of Mg (OH)2 which can improve the corrosion resistance of the alloy after laser combining alkaline treatment, as well as the corrosion rate is almost the stable, which is much smaller than both of uncoated and laser surface processing. The study of the electrochemical corrosion behavior shows that the corrosion potential of the alloy with coated of laser combining alkaline treatment is improved 0.1277 V than that of laser treatment, and the corrosion current is decreased 470.2 muA than laser treatment. The corrosion resistant ability of Mg-4.0Zn-1.5Sr alloy is greatly improved by means of laser combining alkaline treatment.