Effects Of Foaming Conditions Research Articles

Effect of foaming conditions and drying temperatures on total polyphenol content and drying rate of foam-mat dried banana powder: Modeling and optimization study

This study aims to optimize the parameters of the foam-mat drying to produce banana powder. Input parameters of the foam drying such as foaming agent (egg albumin) concentration used from 5 to 15 %, the foam stabilizer (maltodextrin) used from 1 to 3 % and the drying temperature varied between 60 and 80 °C. Factors with 3 levels are arranged according to the Box-Behnken design, which further modelled by RSM (response surface methodology) and ANN (artificial neural network), and optimized. The drying rate and total polyphenol content (TPC) of banana powder under the studied conditions were determined as the target output. The moisture, color, total polyphenol, antioxidant activity and some physical parameters of final fine powder were analyzed. Increasing temperature has increased the drying rate. In addition, increasing the concentrations of egg albumin and maltodextrin maintained the highest TPC and maximum drying rate. ANN model showed the higher forecasting capacity than that of RSM. Moreover, simultaneous optimization of two responses (TPC and drying rate) was selected to maximize the desired value at the concentration of albumin, maltodextrin and drying temperature of 11.86 %, 1.92 %, 74.94 °C, respectively, corresponding to the highest TPC value and drying rate of 1.31 mgGAE/g DW and 2.48 g water/g dry matter/min. At this condition, the drying time was recorded as 103 min. Validation of the optimal ratios showed that the experimental values of TPC and drying rate were in good agreement with the model predicted data. The moisture content and water activity of product were found to be 5.87 ± 0.07 % and 0.37 ± 0.01. The product had bright colors with L*, a* and b* values were measured as 86.4 ± 0.5, 1.75 ± 0.08 and 15.2 ± 0.3, respectively. The high DPPH radical scavenging activity was detected (53.5 %) with the water solubility index and water absorption index of banana powder was determined at value of 56.98 % and 5.17 g/g, respectively. Foam mat dried banana powder was well preserved in paper packaging with aluminum foil.

Porous amino acid-functionalized poly(ionic liquid) foamed with supercritical CO2 and its application in CO2 adsorption

Design and synthesis of porous materials as efficient CO2 adsorbents have attracted much attention to alleviate the environmental issues derived from CO2 emission. Here a new amino acid-functionalized poly(ionic liquid) poly[1-(p-vinylbenzyl)-3-methylimidazolium glycinate] [P([VBMI][Gly])] was prepared with [VBMI][Cl] and P([VBMI][Cl]) as intermediate products. Chemical structures of the above materials are confirmed by NMR and FT-IR spectra. P([VBMI][Gly]) presents dense monolith with amorphous structure and high thermal stability. CO2 adsorption capacity of P([VBMI][Gly]) is 104 mg CO2/g PIL. To further improve CO2 adsorption performance, porous-P([VBMI][Gly]) was constructed via supercritical foaming technology for the first time. The effects of foaming conditions on the morphology and CO2 adsorption performance of porous-P([VBMI][Gly]) were investigated. And porous-P([VBMI][Gly]) foamed at 110 °C, 30 MPa and 2 h presents uniform cell distribution and obvious porous structure. CO2 adsorption capacity of porous-P([VBMI][Gly]) can reach up to 165 mg CO2/g PIL, which is significantly higher than that of pristine P([VBMI][Gly]). Compared with pristine P([VBMI][Gly]), the pore parameters of porous-P([VBMI][Gly]) are obviously improved, and the porosity and average pore diameter can reach 82.9% and 3 μm respectively. Its CO2 adsorption capacity decreases by 25% after twelve-cycle adsorption–desorption experiments.

Fabrication of highly interconnected porous poly(ɛ-caprolactone) scaffolds with supercritical CO2 foaming and polymer leaching

Highly interconnected porous poly(ɛ-caprolactone) (PCL) scaffolds combined with supercritical carbon dioxide (CO2) foaming and a polymer leaching process were fabricated by blending PCL with water-soluble poly(ethyleneoxide) (PEO) as a sacrificial material. The effects of foaming conditions and the phase morphology of blend on foaming behavior and pore morphology were investigated. Rheological results and phase morphology indicated that the PCL and PEO were immiscible. For both spherical droplets and co-continuous phase morphologies of PCL/PEO blend, batch foaming experimental results indicated that increasing CO2 saturation time and foaming pressure led to significant decreases in pore size, but increasing temperature led to opposite results. The incorporation of PEO not only facilitated the foaming of PCL by increasing its viscosity, but it also improved the porosity and interconnectivity of the post-leached PCL scaffolds. The porosity improved by up to 93.5%, and the open pore content increased by up to 90.9% for the PCL50 blend (50% PCL by weight). The leaching process had more contribution on the open pore content for PCL/PEO porous scaffolds with co-continuous phase morphologies than for the spherical droplet structures due to different cell-opening mechanisms. The results gathered in this study may provide a theoretical basis and data to support research into porous scaffolds for tissue engineering.

A simple method for preparation of microcellularPLA/calcium carbonate nanocomposite using super critical nitrogen as a blowing agent: Control of microstructure

AbstractA simple method was used to prepare microcellular foams of poly(lactic acid) (PLA) and its nanocomposites to improve its shortcomings such as low impact resistance and high cost. The batch foaming process of purePLAandPLAfilled with Nano calcium carbonate (NCC) was conducted using supercritical nitrogen (N2) as a blowing agent. The effect ofNCCon crystallization ofPLAis discussed as a remarkable parameter in foaming of semicrystalline polymers. Differential scanning calorimetry (DSC) was used to optimize the process temperature. The effect of foaming conditions (temperature, pressure, and cooling rate) and nanoparticle content on the foam microstructure ofPLAand its nanocomposites were investigated using scanning electron microscopy (SEM). Foams were obtained in the range of macro‐ and microscale (different cell sizes) using different foaming conditions. The results revealed that nanoparticles show excellent nucleation performance onPLAfoaming. Results of dynamic mechanical thermal analysis (DMTA) also showed significant influences ofNCCon foamed and prefoamed samples to different foaming structures.

Synthesis of carbon foam with high compressive strength from an asphaltene pitch

Carbon foams were synthesized using an asphaltene pitch as a carbon precursor. The effects of foaming conditions and carbonization on the pore structures and physical properties of the carbon foams were investigated. Results indicate that the average pore size and density of as-synthesized carbon foams were about 150 μm and 800 kg/m3, respectively. The compressive strength of the carbon foam increased from 10 to 18.7 MPa after carbonization at 1323 K. The high ash content (41.76%) of the pitch plays an important role in determining the density and compressive strength of the carbon foams. [New Carbon Materials 2013, 28(2): 127–133]

Synthesis of carbon foam with high compressive strength from an asphaltene pitch

Carbon foams were synthesized using an asphaltene pitch as a carbon precursor. The effects of foaming conditions and carbonization on the pore structures and physical properties of the carbon foams were investigated. Results indicate that the average pore size and density of as-synthesized carbon foams were about 150 μm and 800 kg/m3, respectively. The compressive strength of the carbon foam increased from 10 to 18.7 MPa after carbonization at 1 323 K. The high ash content (41.76%) of the pitch plays an important role in determining the density and compressive strength of the carbon foams.