scholarly journals Study of the Annealing Effect of Starch/Polyvinyl Alcohol Films Crosslinked with Glutaraldehyde

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 249
Author(s):  
Edgar Franco ◽  
Rosmery Dussán ◽  
Diana Paola Navia ◽  
Maribel Amú
Keyword(s):  
Response Surface Methodology ◽  
Citric Acid ◽  
Polyvinyl Alcohol ◽  
Response Surface ◽  
Crosslinking Agent ◽  
Scanning Calorimetry ◽  
Citric Acid Concentration ◽  
Elongation At Break ◽  
Heat Treated ◽  
Complementary Analysis

Films were fabricated using a mixture of polyvinyl alcohol (PVA)/cassava starch and incorporated citric acid in a concentration range between 5% and 40%. The films were annealed through thermal treatment in a temperature range between 30 °C and 90 °C with 0.3% glutaraldehyde incorporated as the crosslinking agent. This study presents the results of an experimental design analyzed using the response surface methodology. The multiple regression analysis allowed us to obtain the second-order models, which relate the annealing factors and citric acid concentration to Maximum Tensile Strength (MTS), Young’s Modulus (YM), and the Maximum Elongation at Break (MEB). The optimization and validation of the obtained model were carried out with error values below 10.08% for all the response variables, indicating that the response surface methodology and optimization were correct. Finally, as a complementary analysis, the differential scanning calorimetry (DSC) and Fourier-transform infrared spectroscopy (FTIR) tests were carried out, which revealed a higher packaging of the heat-treated films and verified their crosslinking.

scholarly journals Development of poly(vinyl alcohol)-based membranes by the response surface methodology for environmental applications

2020 ◽  
Vol 24 ◽  
pp. e5
Author(s):  
Juliana Zanol Merck ◽  
Camila Suliani Raota ◽  
Jocelei Duarte ◽  
Camila Baldasso ◽  
Janaina Da Silva Crespo ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Citric Acid ◽  
Response Surface ◽  
Acid Concentration ◽  
Vinyl Alcohol ◽  
Membrane Preparation ◽  
Poly Vinyl Alcohol ◽  
Esterification Reaction ◽  
Citric Acid Concentration ◽  
Ft Ir

The pollution of hydric sources by pharmaceuticals is an issue in many countries, particularly in Brazil. The presence of these substances causes deleterious effects on the environment and human health. One of the main sources of this contamination is domestic sewage, due to the expressive amount of medicines released in their unaltered form. Unfortunately, traditional wastewater treatment is not effective for the removal of pharmaceuticals and, for this reason, membrane technology is an attractive alternative to overcome this issue. In this regard, hydrophilic polymers, such as poly(vinyl alcohol) (PVA), are the most suitable. However, their high affinity with water causes intense swelling, leading to severe modifications in the membrane properties. In view of all these facts, the present work evaluated the swelling of PVA-based membranes, with the aim of finding the membrane preparation method that has the lowest swelling, thereby providing the most suitable characteristics for pharmaceutical removal from wastewater. The membranes were prepared by the casting of a polymeric solution, with PVA as a basis polymer, citric acid as a crosslink agent and glycerol and silver nanoparticles as performance additives. The process optimization was performed using a design of experiments with posterior analysis by the response surface methodology (RSM). The RSM assessed the effect on the membrane swelling of the factors, including citric acid concentration and the time and temperature of crosslinking. The membrane characterization was performed by Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy coupled with a field emission gun (SEM-FEG) and water contact angle (WCA) measurements. Overall, the condition that showed the lowest swelling was obtained with 10% of citric acid and crosslinking for 4 h at 130 °C. Under these conditions, the membrane had a mass swelling of 42% and a dimensional swelling of 24%. Additionally, our statistical analysis revealed that the factors with the dominant effects were the citric acid concentration and the temperature of crosslinking. The FT-IR analysis suggested that the crosslinking occurred by an esterification reaction, as showed by the stretching frequencies of C=O at 1710 cm-1 and ester C-O at 1230 cm-1. Moreover, the SEM-FEG images revealed a smooth and flat surface and a dense cross section with a thickness of ~113 μm. Concerning the WCA, the angle was at ~80°, which is characteristic of hydrophilic materials. Finally, the data suggested that it is possible to optimize the membrane preparation process with adequate properties so that it can be subsequently applied to the removal of pharmaceuticals from hospital wastewater.

scholarly journals OPTIMIZATION OF SWEET GUAVA (Psidium guajava, L)  USING THE ACCEPTANCE TEST, RESPONSE SURFACE METHODOLOGY AND PREFERENCE MAP

2012 ◽  
Vol 30 (1) ◽  
Author(s):  
CAMILA CARVALHO MENEZES ◽  
SORAIA VILELA BORGES ◽  
JOÃO DE DEUS SOUZA CARNEIRO ◽  
MARCELO ANGELO CIRILLO ◽  
ANA CARLA MARQUES PINHEIRO ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Citric Acid ◽  
Response Surface ◽  
Consumer Preferences ◽  
Consumer Preference ◽  
Potassium Sorbate ◽  
Acceptance Test ◽  
Citric Acid Concentration ◽  
Independent Variables ◽  
Preference Map

This study aimed to evaluate the influence of the independent variables concentration of citric acid, concentration of potassium sorbate, and pulp/sugar ratio on consumer acceptance for sweet guava. The results were analyzed using statistical methods such as preference map and response surface methodology to determine the influence of the independent variables. Response surface methodology alone proved insufficient to achieve an optimal formulation for the preparation of sweet guava. Based on preference mapping analysis, consumer preference was observed for treatments using higher concentrations of sugar and citric acid. Parameters of sweetness, appearance and texture influenced consumer preferences.   

scholarly journals PENGGUNAAN RESPONSE SURFACE METHODOLOGY PADA OPTIMASI PROSES PENGOLAHAN BAWANG MERAH IRIS IN BRINE

2019 ◽  
Vol 15 (1) ◽  
pp. 12
Author(s):  
NFN Ratnaningsih ◽  
Desty Vidiantika ◽  
Ermi Sukasih ◽  
NFN Setyadjit
Keyword(s):  
Response Surface Methodology ◽  
Citric Acid ◽  
Response Surface ◽  
Acid Concentration ◽  
Salt Concentration ◽  
Heating Time ◽  
Anthocyanin Content ◽  
Minimal Processing ◽  
Citric Acid Concentration ◽  
Design Expert

<p>Bawang merah merupakan komoditas hortikultura yang mudah rusak dan terkadang mengalami kelangkaan di pasaran. Hal ini menimbulkan masalah serius, seperti harga yang fluktuatif dan terjadinya inflasi. Citarasa bawang merah yang khas menyebabkan keberadaannya dipandang penting oleh masyarakat. Untuk mengatasi tidak kontinunya stok bawang merah di pasaran, perlu dilakukan pengolahan minimal proses, seperti pengolahan bawang merah iris in brine. Tujuan penelitian ini adalah untuk menentukan kondisi optimum proses pembuatan bawang merah iris in brine. Optimasi proses dilakukan menggunakan Response Surface Methodology (RSM). Pengolahan data menggunakan Program Design Expert 7.0 dengan tiga faktor, yaitu X1 (konsentrasi garam, %), X2 (konsentrasi asam sitrat, %) dan X3 (lama pemanasan, menit). Hasil optimal diperoleh pada kondisi konsentrasi garam 2,5%, asam sitrat 0,73% dan lama pemanasan 5 menit. Bawang merah iris in brine hasil optimasi memiliki nilai Aw 0,895; nilai chroma 16,97; pH 3,47; total padatan terlarut (TPT) 7,84 ᵒBrix dengan kandungan antosianin 20,21 ppm, kandungan senyawa volatil 91,30 ppm dan aktivitas antioksidan 154,25 ppm.</p><p> </p><p><strong>The use of Response Surface Methodology on optimization of in brine shallot slices production</strong></p><p><br />Shallot is a horticultural commodity that easily damaged and sometimes become scarcity in the market. This triggered serious problems, such as fluctuating prices and inflation. Typical of shallot flavor causes its existences to be considered as important by society. To overcome the uncontinuous stock of shallot in the market, it is necessary to process shallot using minimal processing, such as shallot slices in brine. The objective of this study was to determine the optimum condition of the shallot slices in brine making process. Optimization of the prosess was done using Response Surface Methodology (RSM). Data were processed using Design Expert 7.0, with three factors, namely X1 (salt concentration,%), X2 (citric acid concentration,%) and X3 (duration of heating, minutes). The optimization result was 0.75% citric acid concentration, 2.5% salt concentration and 5 minutes of heating time. The resulting shallot slices in brine has 0.895 of Aw value; 16.97 of Chroma value; 3.47 of pH; 7.84oBrix of total soluble solid (TSS); 20.21 ppm of anthocyanin content; 91.30 ppm of volatile reducing substances (VRS); and 154.25 ppm of antioxidant activity.</p>

scholarly journals The effect of heat treatment and impact angle on the erosion behavior of nickel-tungsten carbide cold spray coating using response surface methodology

2021 ◽  
Author(s):  
Marios Kazasidis ◽  
Elisa Verna ◽  
Shuo Yin ◽  
Rocco Lupoi
Keyword(s):  
Heat Treatment ◽  
Response Surface Methodology ◽  
Mass Loss ◽  
Tungsten Carbide ◽  
Response Surface ◽  
Spray Coating ◽  
Impact Angle ◽  
Control Factors ◽  
Heat Treated ◽  
The Impact

AbstractThis study elucidates the performance of cold-sprayed tungsten carbide-nickel coating against solid particle impingement erosion using alumina (corundum) particles. After the coating fabrication, part of the specimens followed two different annealing heat treatment cycles with peak temperatures of 600 °C and 800 °C. The coatings were examined in terms of microstructure in the as-sprayed (AS) and the two heat-treated conditions (HT1, HT2). Subsequently, the erosion tests were carried out using design of experiments with two control factors and two replicate measurements in each case. The effect of the heat treatment on the mass loss of the coatings was investigated at the three levels (AS, HT1, HT2), as well as the impact angle of the erodents (30°, 60°, 90°). Finally, the response surface methodology (RSM) was applied to analyze and optimize the results, building the mathematical models that relate the significant variables and their interactions to the output response (mass loss) for each coating condition. The obtained results demonstrated that erosion minimization was achieved when the coating was heat treated at 600 °C and the angle was 90°.

scholarly journals Determination of Optimum Composition of Fermentation Medium for Citric Acid Production from Watermelon Rinds using Response Surface Methodology

2017 ◽  
Vol 1 (1) ◽  
pp. 12-16
Author(s):  
Andrew Amenaghawon ◽  
◽  
Oluwatoba Salokun ◽  
Justina Okhonmina ◽  
Imuetinyan Egharevba ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Citric Acid ◽  
Response Surface ◽  
Acid Production ◽  
Fermentation Medium ◽  
Optimum Composition ◽  
Citric Acid Production

scholarly journals Media optimization for C-phycocyanin production in Plectonema sp. using response surface methodology and central composite design

2020 ◽  
Vol 11 (3) ◽  
pp. 3897-3904
Author(s):  
Arbab Husain ◽  
Fahad Khan ◽  
Khwaja Osama ◽  
Sadaf Mahfooz ◽  
Adeeba Shamim ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Citric Acid ◽  
Central Composite Design ◽  
Response Surface ◽  
Nostoc Muscorum ◽  
Therapeutic Implications ◽  
Medium Components ◽  
Anabaena Sp ◽  
Different Strains ◽  
Central Composite

Cyanobacteria represent the richest sources of phycobiliproteins with especial reference to C-phycocyanin (C-PC), which in turn holds exhaustive therapeutic implications. Screening of several cyanobacterial strains namely Anabaena sp., Nostoc muscorum, Cylindrospermum sp., Plectonema sp., Scytonema sp., Spirulina sp., Synechococcous sp. and Tolypothrix sp. was carried out for their C-PC producing capacity, however the produced quantity of C-PC varies greatly among different strains. Owing to the crucial role of different media constituents on productivity of C-PC the current study was designed to optimize most appropriate media composition for augmented CPC production by selected superior producer. 36 factorial central composite design (CCD) dependent response surface methodology (RSM) was utilized to estimate the important medium components attributed with influencing C-PC productivity. RSM analysis of five independent coded factors including Na2CO3, K2HPO4, NaNO3, citric acid and EDTA were analyzed preceded by recognition of efficient variables for algal components production by Plectonema sp. Investigation of results revealed that the eminent medium components were NaCO3 (0.4 g/L); NaNO3 (0.5 g/L); K2HPO4 (2.8 g/L); citric acid (0.08 g/L) and EDTA (0.01 g/L) respectively. The optimized combination yielded 0.5536 mg/ml of C-PC. The increment of C-PC yield is R-Sq = 88.2%. Thus, our study led to the recognition of critical nutritional component that can be used further for enhanced productivity of C-PC.

scholarly journals Parameters Optimization in Compression Molding of Ultra-high Molecular Weight Polyethylene/Cellulose Nanofiber Bio-nanocomposites by using Response Surface Methodology

2020 ◽  
Vol 28 (S2) ◽  
Author(s):  
Nur Sharmila Sharip ◽  
Hidayah Ariffin ◽  
Yoshito Andou ◽  
Ezyana Kamal Bahrin ◽  
Mohammad Jawaid ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Processing Condition ◽  
Compression Molding ◽  
Parameters Optimization ◽  
Cellulose Nanofiber ◽  
Consolidation Process ◽  
Elongation At Break ◽  
Optimal Processing ◽  
Ultra High Molecular Weight

Conventional UHMWPE molding involves long pressure holding duration, nevertheless in the presence of filler such as cellulose nanofiber (CNF), this may contribute to filler degradation. This study optimized the compression molding parameters of UHMWPE/ CNF bio-nanocomposite by using response surface methodology (RSM) in consideration of temperature, pressure and duration as variables. An optimal processing condition of 180°C, 15 MPa, and 20 minutes contributed to more than 80% desirability with tensile strength, yield strength, elongation at break, and Young’s modulus values of 22.83 MPa, 23.14 MPa, 487.31%, and 0.391 GPa, accordingly. Mechanical properties of UHMWPE/CNF bio-nanocomposites molded at optimized processing conditions were comparably similar to those prepared at conventional processing condition, and with the advantage of having shorter processing time. The results presented herewith provides insight towards a more practical approach for UHMWPE/CNF bio-nanocomposites consolidation process.

scholarly journals Investigation on tensile properties of epoxy/graphene nano-platelets/carboxylated nitrile butadiene rubber ternary nanocomposites using response surface methodology

2019 ◽  
Vol 9 ◽  
pp. 184798041985584 ◽  
Author(s):  
Mohammadhossein Saberian ◽  
Faramarz Ashenai Ghasemi ◽  
Ismail Ghasemi ◽  
Sajjad Daneshpayeh
Keyword(s):  
Tensile Strength ◽  
Response Surface Methodology ◽  
Tensile Properties ◽  
Response Surface ◽  
Tensile Modulus ◽  
Curing Temperature ◽  
Butadiene Rubber ◽  
Elongation At Break ◽  
Low Concentration ◽  
Nitrile Butadiene Rubber

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%.

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