Synthesis of flexible polyurethane foam for applications in planar orthosis using the response surface methodology

In this work, the process for the formulation of flexible polyurethane foam is presented following a design of experiments for mixtures. The proportion of polyol, diisocyanate, and crosslinker was considered as factors. The response variables considered were foaming time and reaction temperature. The result of the experiments showed that there is an area where the foam formulation is better. This zone is closed with 5% crosslinker, 50% polyol, and 45% diisocyanate, in this formulation denser foams with more uniform bubbles were obtained

Influence of MWCNT Coated Nickel on the Foaming Behavior of MWCNT Coated Nickel Reinforced AlMg4Si8 Foam by Powder Metallurgy Process

This research studies the effect of multi-wall carbon nanotube (MWCNT) coated nickel to foaming time on the foam expansion and the distribution of pore sizes MWCNT reinforced AlMg4Si8 foam composite by powder metallurgy process. To control interface reactivity and wettability between MWCNT and the metal matrix, nickel coating is carried out on the MWCNT surface. Significantly, different foaming behavior of the MWCNT coated nickel reinforced AlMg4Si8 was studied with a foaming time variation of 8 and 9 min. Digital images generated by the imaging system are used with the MATLAB R2017a algorithm to determine the porosity of the surface and the pore area of aluminum foam efficiently. The results can have important implications for processing MWCNT coated nickel reinforced aluminum alloy composites.

Shaping of Aluminum Foam During Foaming of Precursor Using Steel Mesh with Various Opening Ratios

In this study, steel meshes with various opening ratios φ were used to shape aluminum foams during precursor foaming. The effect of φ on the heating rate and shape of the obtained aluminum foams was investigated. It was found that steel meshes with various opening ratios can be used to shape aluminum foam. There is no significant effect on the pore structures of the obtained aluminum foams when upward expansion is restricted during foaming, regardless of the value of φ. The meshes with higher φ clearly transfer the mesh pattern onto the surface of the aluminum foam but require a shorter foaming time. In contrast, the lower-φ meshes produce aluminum foams with a smoother surface but a longer foaming time is required.

Influence of Material and Arrangement Mold on the Foaming Behavior of Extruded Precursor

In this paper, the extruded precursors were prepared by Powder compact method (PCM),with two different powder AlSi10 or pure Al mixed foaming agent ZrH2 or TiH2, then they were foamed to fill the hollow part. L9 (33) orthogonal test was planned, including three factors, furnace temperature; foaming time; and arrangement mode. The results indicated that the pore structure were effectively improved through adjusting the arrangement mode of precursors. The specimens have been obtained the homogeneous foam expansion when the AlSi10-TiH2 agent were arranged on the top while AlSi10-ZrH2 agent precursors at the bottom in the hollow, and foamed 14 min~16 min at 800 °C

Foaming of industrial lean methyldiethanolamine solution in the presence of hydrocarbon and fatty acid based corrosion inhibitors

In natural gas sweetening alkanolamine processes one of the regularly used chemical is the corrosion inhibitor. For better operation of the plant it is essential to understand the effect of their presence on foaming of industrial lean Methyldiethanolamine (MDEA) used as solvents at different temperatures. This study aimed at investigating the effect of HydroCarbon Based (HCB) and fatty acid based corrosion inhibitor having chemical name Bis(2-Hydroxyethyl)Cocoalkylamine (BHCL) on the foaming tendency of industrial real lean MDEA solutions. Experiments were conducted with different operating parameters, including liquid volume of the solution, foaming time, flow rate of nitrogen gas, concentration of the corrosion inhibitors, temperature of the solution, and gas diffuser pore size using the Foam Scan instrument. With the increase in solution volume and foaming time foaming happens to be more. The foaming tendency of lean MDEA solutions decreased with increasing temperature in absence of corrosion inhibitors but showed different behavior in their presence. At small diffuser pore size and high gas flow rate, the final foam volume increased in the presence of HCB but decreased with the BHCL inhibitor. Optimizing the operating parameters to minimize foaming was verified to be a function of the type of inhibitor used.

Controlled foaming of polycarbonate/polymethyl methacrylate thin film with supercritical carbon dioxide

The polycarbonate (PC)/polymethyl methacrylate (PMMA) (10/90) blends with microcellular foams were prepared by the two-step process using supercritical carbon dioxide as physical foaming agent. The effects of saturation temperature, saturation pressure, foaming temperature, and foaming time on the cell morphology structure were investigated by scanning electron microscopy. The results indicated that the mean diameter of cells in foamed PC/PMMA films decreased with the increment of saturation temperature and saturation pressure but increased with the increment of the foaming time. Moreover, the mean diameter of cells decreased first, but then increased with the increment of the foaming temperature. The cell density ( Nc) increased with the increment of saturation temperature and saturation pressure but decreased with the increment of the foaming time. However, the Nc increased first but then decreased with the increment of the foaming temperature.

Study of Influence of Sensitization Process on Quality of Mixed Emulsion Explosive

Repeated experiments were done to study of influence of sensitization process on quality of mixed loading emulsion explosive, the results show that: The ratio of the sensitizing agent at 1:10 ~1:30 are more appropriate; the density of mixed loading emulsion explosive is gradually decreased while concentration of sensitizing agent increased. Emulsion explosive quality is affected by foaming time under the condition of the certain proportion of sensitizer and constant temperature, when the sensitizer mixing time extended to a certain value, the density tends to be stable. Under the condition of invariable sensitizer concentration, proper temperature not only obtain good blasting effect, but also improve the charging efficiency and shorten the charging time; the temperature between 30~50 °C is more appropriate when the ratio of sensitizer is certain.

Warm mix asphalt by water-containing methodology: a laboratory study on workability properties versus micro-foaming time

This paper focuses on a laboratory investigation of compaction characteristics of warm mix asphalt produced with the addition of synthetic zeolites. The influence of the time elapsed between mixing and compaction operations on mix compactibility was evaluated to define an optimum “micro-foaming time” (MFT), in which the additive can completely release the water contained. A comparison between traditional hot mix asphalt and warm mixes was carried out; two compaction methods (impact and gyratory) were used. Mix compactibility was firstly evaluated in terms of air voids content for each condition of compaction (immediately after mixing or after 1–2 h of storage in an oven). Mix resistance to densification and to distortion was investigated by means of compaction indexes and traffic indexes. Data showed that the foaming process due to the addition of the zeolite has a peak value of intensity after 1 h of MFT. This effect seems to vanish after a longer period of time. Outcomes of this study are expected to benefit both practitioners and researchers.