scholarly journals Optimization of Rice Husk Ash-Based Geopolymers Coating Composite for Enhancement in Flexural Properties and Microstructure Using Response Surface Methodology

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 165 ◽  
Author(s):  
Mohd Salahuddin Mohd Basri ◽  
Faizal Mustapha ◽  
Norkhairunnisa Mazlan ◽  
Mohd Ridzwan Ishak

If the coating is sufficiently flexible, no tears, cracks, or debond will occur. Although geopolymers have a great potential as a coating material, research on the flexural properties is very limited. In this study, a three-point bending test and scanning electron microscope were used to investigate the flexural properties and microstructure of the geopolymer composite coating (GCC), respectively. Response Surface Methodology (RSM) consists of a combination of mathematical and statistical techniques, which is useful in modelling, analyzing, and optimizing responses that are influenced by several factors. It was used in determining the relationship between each factor and determining the best composition for the composite coating. Several factors were considered including ratio of activated alkaline (AA) solution (V1), RHA/AA ratio (V2), and curing temperature (V3). Results showed that the RHA/AA ratio mostly influenced the response, followed by curing temperature while the ratio of AA was not significant. Lower V2 and V3 values provided the highest flexural strength and modulus. The optimum composition which provided the best coating of flexural properties were V1 = 3.5, V2 = 0.39, and V3 = 45.7 °C. Microscopic images showed that coating with high flexural properties (ductile coating) exhibited minor and rough cracks as compared to that of coating with low flexural properties (brittle coating) which displayed a crack with a clean linear cut. Brittle coating was highly agglomerated and has a significant negative effect on the flexural properties. By developing the optimum composition, the GCC may potentially be a good alternative as a building construction coating material.

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2709
Author(s):  
Mohd Salahuddin Mohd Basri ◽  
Faizal Mustapha ◽  
Norkhairunnisa Mazlan ◽  
Mohd Ridzwan Ishak

As a result of their significant importance and applications in vast areas, including oil and gas, building construction, offshore structures, ships, and bridges, coating materials are regularly exposed to harsh environments which leads to coating delamination. Therefore, optimum interfacial bonding between coating and substrate, and the reason behind excellent adhesion strength is of utmost importance. However, the majority of studies on polymer coatings have used a one-factor-at-a-time (OFAT) approach. The main objective of this study was to implement statistical analysis in optimizing the factors to provide the optimum adhesion strength and to study the microstructure of a rice husk ash (RHA)-based geopolymer composite coating (GCC). Response surface methodology was used to design experiments and perform analyses. RHA/alkali activated (AA) ratio and curing temperature were chosen as factors. Adhesion tests were carried out using an Elcometer and a scanning electron microscope was used to observe the microstructure. Results showed that an optimum adhesion strength of 4.7 MPa could be achieved with the combination of RHA/AA ratio of 0.25 and curing temperature at 75 °C. The microstructure analysis revealed that coating with high adhesion strength had good interfacial bonding with the substrate. This coating had good wetting ability in which the coating penetrated the valleys of the profiles, thus wetting the entire substrate surface. A large portion of dense gel matrix also contributed to the high adhesion strength. Conversely, a large quantity of unreacted or partially reacted particles may result in low adhesion strength.


2017 ◽  
Vol 1 (1) ◽  
pp. 12-16
Author(s):  
Andrew Amenaghawon ◽  
◽  
Oluwatoba Salokun ◽  
Justina Okhonmina ◽  
Imuetinyan Egharevba ◽  
...  

2019 ◽  
Vol 9 ◽  
pp. 184798041985584 ◽  
Author(s):  
Mohammadhossein Saberian ◽  
Faramarz Ashenai Ghasemi ◽  
Ismail Ghasemi ◽  
Sajjad Daneshpayeh

In this study, the response surface methodology was used to investigate the tensile properties of epoxy/graphene nano-platelets/carboxylated nitrile butadiene rubber ternary nanocomposites. Box–Benhken method was used to design experiments for four factors consisting of graphene nano-platelets (at 0, 0.75, and 1.5 wt%), carboxylated nitrile butadiene rubber (0, 5, and 10 wt%), hardener contents (80, 90, and 100 phr), and also different post curing temperature (130, 140, and 150°C). After the samples were prepared, a tensile test was performed to obtain the tensile strength, tensile modulus, and elongation at break of nanocomposites. Moreover, field-emission scanning electron microscopy was used to observe the state of graphene nano-platelets dispersion. The results obtained from the tensile tests showed that increasing the graphene nano-platelets, carboxylated nitrile butadiene rubber, and hardener contents and high post curing temperature reduced the tensile strength. The optimum value of tensile modulus was achieved at low concentration of carboxylated nitrile butadiene rubber and high contents of graphene nano-platelets, whereas maximum elongation at break occurred at high content of carboxylated nitrile butadiene rubber and low concentration of graphene nano-platelets and hardener. In addition, a second-order polynomial model was used to correlate the tensile properties of ternary nanocomposites to the desired factors. Finally, contour plots were used to determine optimum values of the desired factors. It was seen that the presence of 10 wt% of carboxylated nitrile butadiene rubber in the epoxy matrix increased the elongation at break by the considerable amount of ∼49%.


2021 ◽  
Vol 1039 ◽  
pp. 518-536
Author(s):  
Abbas H. Jeryo ◽  
Jumaa S. Chiad ◽  
Wajdi S. Abbod

In this process, optimum laminating properties were used in producing prosthesis and orthoses were researched and selected based on high yield, ultimate stresses, stresses of bending and fatigue properties. The process of the optimal selection is the Response Surface Methodology (RSM), which has been used to reach two parameters: reinforcement perlon fiber and percent of multi-strand carbon MWCNT nanotube combined with the matrix resin. The response surface methodology is a combination of mathematician and statistic techniques which are used for experimental model building and analysis of problems. This technique revealed 13 separate laminations samples with a percentage of separate Perlon layers No. and MWCNT Wt %. Tests were conducted for all lamination materials as defined in RSM methods and rendered by vacuum system, including fatigue tests for the ideal laminating material as opposed to laminations developed in the prior study (three Tensile test, Bending test and Fatigue tests according to the ASTM D638 and D790 respectively). Tests from the system version 10.0.2 of Design Expert found lamination (10 perlon layers and 0.75% of MWCNTs) to be the best according to overall yield, ultimate and bending loads in the 12 other laminations. Fatigue eventually revealed that constraints were applied to the stamina tension (2,66, 1,66) for optimum lamination, relative to ten perlon lamination layers and 424 lamination respectively.


2020 ◽  
Vol 7 (4) ◽  
pp. 37-44
Author(s):  
Xudong Chu ◽  
Huaifang Wang ◽  
Shuying Sui ◽  
Ping Zhu ◽  
Qingdao University

Durable press (DP) finishing process of cotton fabric with 1,2,3,4-butanetetracarboxylic acid (BTCA) was investigated and optimized using the Box-Behnken design (BBD) with a response surface methodology (RSM). BBD experimental data were fitted to create the response surface regression models describing wrinkle recovery angle (WRA) and breaking strength of the finished cotton fabric. Analysis of variance (ANOVA) revealed that the concentration of BTCA was the most significant variable affecting the WRA, followed by the curing time, curing temperature, and concentration of sodium hypophosphite (SHP). Regarding breaking strength, curing time was the most significant variable, followed by the curing temperature, concentration of BTCA, and concentration of SHP. After optimal treatment, the WRA of the finished fabric was 252°, while the retention rate of breaking strength was 69%.


2021 ◽  
pp. 1-22
Author(s):  
Avinash Borgaonkar ◽  
Ismail Syed

Abstract Molybdenum disulphide (MoS2) is popularly used in tribological applications because of its excellent lubricating properties. However, its performance needs to further improve. In the present study, an attempt has been made to improve the wear resistance of pure MoS2 coating by incorporating TiO2 and ZrO2 nanoparticles as a reinforcement material into the MoS2 base matrix. The composite MoS2-TiO2-ZrO2 coating was applied onto substrate surface by bonding technique. The tribological performance of the coated specimens was evaluated employing various operating conditions (such as wt. % of compounding elements, contact pressure, sliding speed) using pin-on-disc friction and wear test rig. A statistical model was developed to identify the significant factors affecting the friction coefficient (COF) and wear rate of the composite coating material. The design of experiment (DOE) were formulated by response surface methodology (RSM) approach to cut down the number of experiments and to develop a mathematical model between the key process parameters such as wt. % of compounding elements, contact pressures, sliding speeds. Analysis of variance (ANOVA) test was executed for checking the adequacy of the empirical models developed. It was discovered that the COF and wear rate of composite MoS2-TiO2-ZrO2 coating significantly affected by the wt. % addition of ZrO2. The SEM and optical microscopy analyses of the worn surfaces and transfer films indicated that the tribological properties of composite MoS2-TiO2-ZrO2 coating were significantly improved compared to pure MoS2 coating.


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