Constant Weight Ratio Research Articles

Synergism of carbonaceous additives in engineering of the supercapacitive performance of α-and λ-phases of manganese oxide

Owing to the presence of valence shells for charge transfer, a high theoretical specific capacitance, and variable redox properties, MnO2 appears as a promising agent in the realm of energy storage. Crystallographic structures of manganese oxide (MnO2), a transition metal oxide, play a crucial role in determining its capacitive behavior by controlling the ion intercalation and double-layer formation. In this work, two different phases of MnO2 were synthesized using the facile chemical reduction method and biological method, say α-MnO2 and λ-MnO2. The phases were incorporated with different carbonaceous additives including GO and CNT while maintaining a constant weight ratio of 8:1:1 between active materials (MnO2), additive, and PVDF binder. Among different composites formed, the best electrode performance is demonstrated by λ-MnO2/CNT/PVDF composite with an excellent specific capacitance of 356 F/g at a scan rate of 1 A/g. Moreover, the best-performing electrodes are investigated with a symmetrical two-electrode system yielding a wide potential window of 1.8V with an outstanding power density of 13.5 KW/Kg at 5 A/g and an energy density of 53.78 Wh/Kg at 1A/g having a specific capacitance of 190 F/g.

New method for assigning cardinal weights in multi-criteria decision-making: the constant weight ratio method

A new method is proposed to convert ordinal ranking of a number of criteria and an additional piece of information into numerical weights. A literature review of methods for assigning cardinal weights based on ordinal ranking is performed, as well as an analysis of their behaviour. The new method, called ‘constant weight ratio’ (CWR), enables better adjustment to the decision-maker’s preferences than purely ordinal ranking methods. It also solves the problem of the excessive decrease in the weight of the most important criterion (or criteria) when the total number of criteria is large and the weight of the most important criterion (or criteria) must be high. It is achieved via three simple steps and flexible input data. The additional piece of information may be: (i) the relative importance of the criteria, i.e., the weight ratio, (ii) the total weight of the most important set of criteria, or (iii) the weight of the most important criterion. The proposed method is applied to two case studies in the cultural sector to illustrate that the resulting weights are equivalent to other methods requiring more input data from the decision maker.

Potential of mango shell powder as a bio filler in flax-jute hybrid epoxy composites: mechanical and wear characterization

Abstract The exploration of natural fillers has garnered considerable attention in response to persistent concerns about material pollution and diminishing resources. In the context of this study, one such natural filler under scrutiny is mango shell powder (MSP), a byproduct derived from mango processing. The central objective of this investigation is to assess the potential of MSP as a filler in flax-jute hybrid epoxy composites, with a keen focus on enhancing their properties. Specifically, the study aims to elucidate the impact of incorporating MSP filler on the mechanical and wear characteristics of these composites. The experimental approach involved the preparation of composite samples with varying weight percentages of MSP filler, ranging from 1 % to 9 % (1 %, 3 %, 5 %, 7 %, and 9 %), while maintaining a constant fiber and matrix weight ratio. The results obtained from the experiments revealed that composite samples containing a 7 % filler exhibited superior mechanical properties, while wear resistance demonstrated a noticeable decrease with the progressive increase in filler content. These findings suggest the potential efficacy of MSP as a filler in enhancing both the mechanical and wear characteristics of flax-jute hybrid epoxy composites, providing valuable insights for further applications in sustainable composite materials.

Experimental investigation on mechanical and tribological analysis of pineapple leaf (Ananas comosus) and sisal (Agave sisalana) fibers reinforced hybrid epoxy composites

Abstract In many industrial applications, natural-fiber-reinforced polymer (NFRP) composites are emerging as a strong substitute for composites based on synthetic fibers. The goal of this study was to examine the mechanical and tribological characteristics, including tensile, flexural, impact, wear, hardness, and water absorption, of hybrid epoxy composites reinforced with pineapple leaf and sisal fibers at various weight fractions. First, 5 % sodium hydroxide was used to treat the pineapple leaf and sisal fibers. With a composition of 0, 10, 15, 20, and 30 wt% of pineapple leaf and sisal fibers to the epoxy resin and its hardener mixture, which had a constant weight ratio of 70 %, hybrid composites were fabricated using the compression moulding process. To create a hybrid epoxy composite reinforced with pineapple and sisal fiber, epoxy resin was used as the binder. Different types of testing were performed on the hybrid composites following ASTM standards. The outcomes were contrasted with composites made from mono-pineapple and sisal fiber composites. In comparison to other composite samples, the 15:15 composite sample exhibited the best mechanical and tribological qualities, including the highest tensile strength, impact resistance, flexural strength, hardness, water absorption resistance, and wear resistance. Using a scanning electron microscope (SEM), the fiber/matrix adhesion was investigated. The 15:15 composite sample exhibits primarily mechanical and tribological properties, making the resultant composite material simpler to use in structural and automotive applications.

Effect of calcium carbonate on the performance of poly(butylene adipate-co-terephthalate) filled with duckweed biomass

Blending poly(butylene adipate-co-terephthalate) (PBAT) and thermoplastic starch (TPS) results in a tough biodegradable plastic. TPS is always produced from edible crop-derived starch. An alternative source of starch and protein polymers, duckweed biomass has a relatively small impact on the human food chain. The present work studies the feasibility of using duckweed biomass as a replacement for cassava starch for TPS production and investigates the effect of calcium carbonate (CaCO3) on the performance of PBAT filled with duckweed biomass. PBAT/TPS and PBAT/duckweed masterbatch (DM) blends with a constant weight ratio of PBAT:TPS and PBAT:DM of 60:40 were prepared using a twin-screw extruder and then molded into dumbbell-shaped specimens using an injection molding machine. PBAT/DM/CaCO3 composites containing CaCO3 in the range of 10%− 30 wt% were also fabricated. Duckweed biomass has the potential to replace cassava starch in PBAT blends; however, the properties of those blends differ. The PBAT/DM blend exhibited higher density and melt flow index, but lower elongation at break, shore D hardness, and thermal stability than PBAT/TPS blend. In addition, DM facilitated the crystallization of PBAT during cooling. Adding CaCO3 could reinforce the PBAT/DM blend, enhancing its Young’s modulus and hardness while reducing tensile strength and elongation at break. Moreover, added CaCO3 improved the thermal stability but reduced the melt flow index of the PBAT/DM blend. The resulting PBAT/DM/CaCO3 composites are promising sustainable materials for biodegradable injection-molded products with an acceptable cost.

Mechanical Character Analysis of Pineapple Fibre Epoxy Composite with Nanoclay Quantity Variation

Epoxy based hybrid composites are extremely wide used materials in the polymer engineering field and always have a demand for their versatile applications. Nano clay is yet another trending substance handled by many researchers due to their enhanced abrasion characteristics. This research was performed to investigate the effect of dispersing nanoclay into epoxy matrix and further coupled with pineapple fibers to fabricate a hybrid composite of excellent mechanical property. 4 layers of Pineapple fiber mats were compression moulded with epoxy nanoclay blend to obtain composite specimens of 4mm thickness. Nanoclay was added into epoxy resin at four different weight ratios (2%, 4%, 6%, and 8%) to form four different combinations of matrix materials into which pineapple fiber mats were reinforced individually at a constant weight ratio of 25%. The enhancement of mechanical and abrasion rate of the hybrid composites were matched with those of the neat Epoxy/Pineapple fiber composites that are currently being developed as alternatives for brake pads. Moisture absorption rate of the composites were analysed to ASTM D570 and Morphology was inspected using Field Emission Scanning Electron Microscope (FESEM). The results depicted optimum mechanical performance at 4 wt% nanoclay infused epoxy/pineapple fiber composite that had a tensile strength of 166.75 MPa, flexural strength of 801.15 MPa and impact strength of 148.76 kg/sq. m. The least abrasion rate was detected in the composite with 8 wt% nanoclay content, resulting in an abrasion rate of 0.1064 g/m.

Preparation of Cellulose Acetate Nanocomposite Films Based on TiO2-ZnO Nanoparticles Modification as Food Packaging Applications

To develop bio-packaging materials, nanocomposite films of cellulose acetate reinforced with titanium dioxide and zinc oxide nanoparticles were prepared, by the casting method at different weight ratios of ZnO nanoparticles (1.5, 2, and 2.5) wt% and a constant weight ratio of 2 wt% TiO2. ZnO and TiO2 nanoparticles were tested using scanning electron microscopy (SEM). The mechanical properties (tensile strength and elongation) were improved at a fixed level of Cellulose Acetate+ 2% TiO2+1.5wt% ZnO loading. Beyond that level of loading, they decreased. The tensile strength was decreased due to some degrees of agglomeration of filler particles above a critical content. Fourier-Transform Infrared Spectroscopy (FTIR) was conducted to reveal the microstructures and chemical composition of as-prepared composite films. The wettability of the films was also determined by the sessile drop method. An increase in contact angle was also observed by the addition of ZnO content from 70.6° to 77.1° compared to pure Cellulose Acetate, which indicated a value of 61.3°. Antibacterial activity against Escherichia coli and Staphylococcus aureus was enhanced after incorporation of ZnO-TiO2 compared with pure CA. The enhanced wettability and antibacterial activity of the prepared films suggest that they could be used for packaging applications.

Mechanical and Water Absorption Properties of Jute/Palm Leaf Fiber-Reinforced Recycled Polypropylene Hybrid Composites

Hybrid composites have proven endless benefits to the research communities in terms of environmental friendliness, mechanical properties, and development of new material. The present work explores the tensile, flexural, impact strengths, and water absorption properties of jute and palm leaf fiber-reinforced hybrid composites. Five types of hybrid composites were fabricated by varying jute and palm leaf fiber percentage of J100:P0, J25:P75, J50:P50, J25:P75, and J0:P100% with a constant weight ratio of polypropylene matrix. The findings showed that jute-palm leaf fiber-reinforced composite had positive effect on tensile, flexural, and impact strength. Experimental results showed that the J25:P75% (jute and palm leaf fiber) exhibited the highest tensile strength of 62.2 MPa and flexural strength of 82.26 MPa due to the optimal interfacial properties between the fibers and matrix. The impact strength of composites increased as the proportion of palm leaf fiber increased. Water absorption increased with jute fiber content, reaching a maximum of 1.26% at composite J100:P0, with lower water absorption at J0:P100% composite due to the higher moisture content of jute fiber.

Bio-based thermoplastic natural rubber based on poly(lactic acid)/thermoplastic starch/calcium carbonate nanocomposites

Bio-based thermoplastic natural rubber (TPNR) has recently received much attention due to its sustainability. TPNR based on natural rubber (NR), poly(lactic acid) (PLA), thermoplastic starch (TPS), and nano-precipitated calcium carbonate (NPCC) was fabricated using a twin-screw extruder with two different mixing sequences: MI (NPCC was first compounded with PLA) and MII (NPCC was initially compounded with TPS), and then converted to a sheet through cast sheet extrusion. A constant weight ratio of NR:PLA:TPS at 30:40:30 and varying concentrations of NPCC at 0.5, 1, 3, and 5 wt% were employed. The effects of NPCC and mixing sequence on the properties of NR/PLA/TPS/NPCC nanocomposites were investigated. The NR and TPS phases were dispersed in the PLA matrix. The nanocomposites loaded with a small amount of NPCC (0.5 and 1 wt%) showed increased tensile strength and Young's modulus. NPCC enhanced melt flowability, slightly improved the water vapor barrier property of the NR/PLA/TPS blend and caused decreased Tg, Tcc, and Tm of PLA in the nanocomposites. The PLA phase of the MI nanocomposites contained a higher amount of NPCC, consequently having greater PLA chain scission and poorer tensile properties than that of the MII nanocomposites.

Effect of high shear rate on the mechanical properties of polyethylene, poly(ethylene terephthalate), polystyrene and polypropylene waste blend

The effect of high shear rate on the mechanical properties of polyethylene (PE), poly(ethylene terephthalate) (PET), polystyrene (PS) and polypropylene (PP) waste blend was investigated. The process was carried out at a temperature of 120°C using a counter-rotating twin-screw extruder. A constant screw speed of 250 rpm and a constant weight ratio of the PE/ PET/PS/PP components of 1:1:1:1 were used. The preliminary research showed that the high shear rate had no effect on the impact strength. However, the significant improvement in the flexural properties was observed as compared to those obtained at a lower screw speed of 80--120 rpm.

The Influence of Silica Nanoparticles on the Thermal and Mechanical Properties of Crosslinked Hybrid Composites.

This paper presents the synthesis and physicochemical characterization of a new hybrid composite. Its main goals are evaluating the structure and studying the thermal and mechanical properties of the crosslinked polymeric materials based on varying chemical properties of the compounds. As an organic crosslinking monomer, bisphenol A glycerolate diacrylate (BPA.GDA) was used. Trimethoxyvinylsilane (TMVS) and N-vinyl-2-pyrrolidone (NVP) were used as comonomers and active diluents. The inorganic fraction was the silica in the form of nanoparticles (NANOSiO2). The hybrid composites were obtained by the bulk polymerization method using the UV initiator Irqacure 651 with a constant weight ratio of the tetrafunctional monomer BPA.GDA to TMVS or NVP (7:3 wt.%) and different wt.% of silica nanoparticles (0, 1, 3%). The proper course of polymerization was confirmed by the ATR/FTIR spectroscopy and SEM EDAX analysis. In the composites spectra the signals correspond to the C=O groups from NVP at 1672–1675 cm−1, and the vibrations of Si–O–C and Si–O–Si groups at 1053–1100 cm−1 from TMVS and NANOSiO2 are visible. Thermal stabilities of the obtained composites were studied by a differential scanning calorimetry DSC. Compared to NVP the samples with TMVS degraded in one stage (422.6–425.3 °C). The NVP-derived materials decomposed in three stages (three endothermic effects on the DSC curves). The addition of NANOSiO2 increases the temperature of composites maximum degradation insignificantly. Additionally, the Shore D hardness test was carried out with original metrological measurements of changes in diameter after indentation in relation to the type of material. The accuracy analysis of the obtained test results was based on a comparative analysis of graphical curves obtained from experimental tests. The values of the changes course of similarity in the examined factors, represented by those of characteristic coefficients were determined based on the Fréchet’s theory.

Retention of albumin in Indonesian shortfin eel meat (Anguilla bicolor) by freeze-drying encapsulation using maltodextrin and gum Arabic as coating materials

Indonesian shortfin eel (Anguilla bicolor) or locally known as sidat eel is one of Indonesia’s important export commodity owing to its nutritional value such as albumin. In this study, encapsulation of freeze-dried sidat eel meat (EM) by biopolymers such as maltodextrin (MD) and and gum Arabic (GA) was examined to find the most effective method to retain its albumin content. Emulsion of biopolymers with a constant weight ratio percentage of 8.00% (w/w, coating material/sidat eel meat) and four different proportions of MD and GA were prepared using a homogenizer, followed by freeze-drying. The 4 different proportions were named T1 (EM 92% + GA 5.33% + MD 2.67%), T2 (EM 92% + GA 2.91% + MD 5.09%), T3 (EM 92% + GA 2.00% + MD 6.00%) and T4 (EM 92% + GA 1.52% + MD 6.46%), respectively. Powders were characterized for its physico-chemical characteristics including colour measurements, moisture content, water solubility, and retention of albumin content. It was observed that T4 consisting of EM with addition of GA (1.52%) and MD (6.46%) as coating materials retained the highest amount of albumin. The encapsulation efficiency were positively influenced by moisture content, solubility and colour measurement differences. To conclude, a mixture of gum Arabic and maltodextrin as coating materials was efficient to retain albumin in EM freeze-drying encapsulation. This necessary information may be valuable to researchers working on food supplements or functional food development.

Extremely slow settling behavior of particles in dilute wormlike micellar fluid with broad spectrum of relaxation times

We selected a 1.4 wt% Octadecyl trimethyl ammonium chloride (OTAC) concentration wormlike micellar fluid with broad relaxation time spectrum and another single relaxation Maxwell fluid of 4.0 wt% OTAC concentration with a constant weight ratio of OTAC to NaSal of 5:1. The shear viscosity, dynamic modulus as well as the extensional viscosity were tested. The steady and unsteady motion of spheres were investigated by high-speed video images in these two wormlike micellar fluids. Extremely slow settling velocity is found when smaller spheres with diameters of 3.2 and 4.0 mm settles in the 1.4 wt% OTAC solution. Stronger rebound of these spheres occurs in this fluid. Comparing with particle settling velocity in inelastic power law fluid, we concluded that this extremely slow sedimentation in the 1.4 wt% OTAC solution seems to be dominated by the slowest stress relaxation of this solution. The rheology test demonstrated that this wormlike micellar fluid has more tensile hardening, low viscosity and strong elasticity. The oscillation of sphere results from the elasticity of the entangled microstructures of wormlike micelles. For a Maxwell viscoelastic 4.0 wt% OTAC solution, settling behaviors of spheres agree with previous literatures that the flow becomes instability as the Wi number exceeds a critical value.

Magnetic nanoparticle incorporated oleogel as iontophoretic drug delivery system

In this article, we validated the use of electric current as an external stimulus to induce an enhancement of drug release from magnetic nanoparticle (MNP) incorporated organogels (magnetogel) under iontophoretic conditions. For this purpose, we adopted a simple, two-step synthesis route to incorporate magnetic (Fe3O4) nanoparticles (MNP) and ciprofloxacin hydrochloride within the network of a soybean oil-based oleogel using stearic acid as gelator. We fabricated a series of MNP incorporated oleogels by varying the wt% of MNPs while keeping a constant weight ratio of soybean oil:stearic acid. The microstructures of the magnetogels were analyzed in MNP concentration-dependent manner by optical microscopy, powder X-ray diffraction, FTIR, mechanical, and electrical studies. Detailed analysis of the electrical properties revealed that the gel sample with a maximum proportion of MNP (S4) allowed the maximum passage of current through it among all the compositions. Under the iontophoretic environment of the active condition, we observed nearly 2.5 fold increase in cumulative drug release in case of sample S4 compared to the corresponding passive condition. These observations suggested that in future, our magnetogel formulation can be further developed as AC field induced ‘remote controlled’ agent for therapeutic application.

Low carbon building: Experimental insight on the use of fly ash and glass fibre for making geopolymer concrete

Abstract Due to the environmental impacts resulting from the production of Ordinary Portland cement (OPC), the drive to develop alternative binders that can totally replace OPC is gaining huge consideration in the construction field. In the current study, attempt was made to determine the strength characteristics of glass fibre-reinforced fly ash based geopolymer concrete. Sodium hydroxide (NaOH) and sodium silicate (Na 2 SiO 3 ) were used as alkaline solutions (for activation of geopolymer reaction) at 12, 16, 20 M. Glass fibres were added to the geopolymer concrete in varying proportions of 0.1–0.5% (in steps of 0.1%) by weight of concrete. A constant weight ratio of alkaline solution to fly ash content of 0.43 was adopted for all mixes. British standard concrete test specimens were cast for measuring compressive strength, split-tensile strength, and flexural strength. Concrete specimens were cured by heating in oven at 90 °C for 24 h and natural environment, respectively. From the results, thermally cured concrete samples had better mechanical properties than the ambient (natural) cured samples. Thermally cured concrete specimen, containing 0.3% glass fibre and 16 M NaoH, achieved a maximum compressive strength of 24.8 MPa after 28 d, while naturally cured samples achieved a strength of 22.2 MPa. There was substantial increase in tensile strength of geopolymer concrete due to the addition of glass fibres. Split tensile strength increased by 5–10% in glass fibre-reinforced geopolymer concrete, containing 0.1–0.5% glass fibre and 16 M NaoH when compared to the unreinforced geopolymer concrete (1.15 MPa).

Improvement of the compatibility between poly(3-hydroxybutyrate) and poly(ε-caprolactone) by reactive extrusion with dicumyl peroxide

Poly(3-hydroxybutyrate) is a biodegradable aliphatic polyester obtained through bacterial fermentation that has gained attention in the last few years; nevertheless, its industrial applications are restricted because of some drawbacks related to its high stiffness and fragility which is associated to its high crystallinity. In this work, poly(3-hydroxybutyrate) (P3HB) was melt blended with poly(ε-caprolactone) (PCL) at a constant weight ratio of 75/25 (P3HB/PCL) by reactive extrusion with different contents of dicumyl peroxide (DCP) in the 0–1wt% range. The effects of the DCP load on mechanical, thermal and morphology of the P3HB/PCL blend were studied. Results showed a positive increase in the elongation at break and the impact-absorbed energy of 91% and 231% respectively with regard the uncompatibilized P3HB/PCL blend by the addition of 1wt% DCP, being this a clear evidenced of the improved compatibility between these polymers. Moreover, morphology of DCP-compatibilized P3HB/PCL blend obtained by field emission electron microscopy (FESEM) and atomic force microscopy (AFM) showed a remarkable decrease in the particle size of poly(ε-caprolactone)-rich domains randomly dispersed in the poly(3-hydroxybutyrate). In addition, both FESEM and AFM also revealed improved interfacial adhesion between P3HB- and PCL-rich phases with a noticeable decrease in the gap between them. Addition of 1wt% DCP also contributes to lowering the degree of crystallinity of PHB by 14% in the blend and other thermal properties are not highly affected by the reactive extrusion with DCP.

Studying saturation mobility, threshold voltage, and stability of PMMA-SiO2-TMSPM nano-hybrid as OFET gate dielectric

PMMA-SiO2-TMSPM (polymethyl methacrylate- silicon oxide- (3-trimethoxysilyl)propyl methacrylate) nano-hybrid solutions were synthesized using sol-gel process with the constant weight ratio of PMMA-SiO2 and different weight ratios of TMSPM. Hybrid solutions were deposited on p-type Si (111) substrate using the spin coating technique. Surface morphology was studied using scanning electron microscopy (SEM) technique and the size of the nanoparticles was about 6nm to 13nm. Capacitance-voltage (C-f) measurements and current-voltage (I–V) curves were also studied in metal-insulator-semiconductor (MIS) structures. According to the results presented from JGS curves in terms of VGS, the gate leakage current densities were small enough to be used as gate dielectric material in OFETs. At VDS=−10V, in the saturation region, it is considered (transfer characteristic curves), maximum mobility μS,FET was related to the sample without TMSPM because of its minimum dielectric constant. However, the surface morphology of this sample shows discontinuous nanoparticles with maximum traps on the path, which led to decreased IDS in the channel. To overcome this challenge, other samples were produced in the presence of TMSPM as the coupling agent. The sample with 0.15wt ratio of TMSPM has flatter surface morphology and more continuous dispersion than that of other samples so that the number of traps on the path decrease, nanoparticles distribute continuously on the surface of the thin films, and IDS increased in the channel. By applying high gate voltages (VGS=−80V), according to IDS curves in terms of VDS, the OFETs show good stability.

Investigation on characterization of Ereen coal deposit

The Ereen coal deposit is located 360 km west from Ulaanbaatar and 95 km from Bulgan town. The coal reserve of this deposit is approximately 345.2 million tons. The Ereen coal is used directly for the Erdenet power plant for producing of electricity and heat. The utilization of this coal for gas and liquid product using gasification and pyrolysis is now being considered. The proximate and ultimate analysis show that the Ereen coal is low rank D mark hard coal, which corresponds to subbituminous coal. The SEM images of initial coal sample have compact solid pieces. The SEM image of carbonized and activated carbon samples are hard material with high developed macro porosity structure. The SEM images of hard residue after thermal dissolution in autoclave characterizes hard pieces with micro porous structure in comparison with activated carbon sample. The results of the thermal dissolution of Ereen coal in tetralin with constant weight ratio between coal and tetralin (1:1.8) at the 450ºC show that 38% of liquid product can be obtained by thermal decomposition of the COM (coal organic matter).Mongolian Journal of Chemistry 16 (42), 2015, 18-21

Mathematical modeling for the prediction of the overall swelling profile from poly (AM-co-AA-co-HEA) hydrogels: effect of glycidyl methacrylate and ammonium per sulphate

In the present investigation, a series of hydrogels based on poly (AM-co-AA-co-HEA) from the constant weight ratio (1/1/1) of acrylamide (AM), acrylic acid (AA), and hydroxy ethyl acrylate (HEA) monomers were synthesized by solution polymerization to optimize the reaction conditions. The reaction conditions were optimized by varying the reaction temperature, reaction time, crosslinker and initiator concentration, and amount of solvent. At optimized reaction conditions, two different sets of hydrogels were synthesized by varying the concentrations of cross-linker (glycidyl methacrylate, GMA) from 1 to 4 % and initiator (ammonium per sulphate, APS) from 1 to 4 %, to study the effects of crosslinker variation as well as initiator variation on swelling ratio by Flory’s equations. The three mathematical models (early time, late time and etters model) were fitted on experimental swelling data to investigate the entire swelling profile of all the hydrogels prepared with various amounts of GMA and APS content. Values of swelling transport exponents showed that the swelling mechanism was shifted from diffusion to relaxation controlled in case of increasing APS content, while only diffusion mechanism was followed for increasing GMA content. The proportionality constant (k) was calculated by two different models (1) power law and (2) Baker and Lonsdale to confirm the validity of early-time model fitting on experimental swelling data.

Stability and rheology of water-in-oil-in-water multiple emulsions made with protein-polysaccharide soluble complexes

The morphology, stability, and rheological properties of water-in-oil-in-water (W1/O/W2) multiple emulsions (ME) stabilized by whey protein concentrate (W)-carboxymethylcellulose (C) soluble complexes (SCW/C) were evaluated. The interaction pH values (pHi) to generate SCW/C were established through zeta potential and turbidity determinations. Six ME variations were prepared using a constant weight ratio (WR) between W and C of 3:1 (where maximum interaction occurred) and by varying the way in which the biopolymers were adsorbed at the interface (layer-by-layer, LL, or pre-formed complex, PF) and pHi (3.7, 4.0 and 4.3). The ME initial volume-surface diameter (D3.2) of the oil droplets ranged from 2.4 to 3.2μm, which on turn contained numerous flocculated water droplets. Higher viscoelastic moduli values (G′ and G″), more pronounced shear thinning behaviour and smaller changes in droplet size with storage time were displayed by ME made with a pHi value of 4.3, WR3:1, and LL biopolymers adsorption technique.