Tapioca starch, poly(lactic acid), and Cloisite NA+ nanocomposite foams, with four clay contents (1, 3, 5, 7, wt %), were prepared by melt-intercalation method. Selected structural, thermal, physical, and mechanical properties were characterized using X-ray diffraction (XRD), scanning electron microscopy, differential scanning calorimetry, and an Instron universal testing machine, respectively....

We describe the fabrication of porous foams with shape memory triggering at body temperature. Employing a modified porogenleaching technique, functionalized poly(3-caprolactone) (PCL) and poly(ethylene glycol) (PEG) macromers are crosslinked via thiol–ene chemistry to generate highly porous foam scaffolds with shape memory capacity. The temperature at which shape change of these scaffolds occur...

Anisotropic polymer foams have been prepared, which exhibit a Poisson's ratio exceeding 1, and ratios of longitudinal to transverse stiffness exceeding 50. The foams are as much as 20 times stiffer in the longitudinal direction than the foams from which they were derived. The transformation process involved applying a uniaxial stress sufficient to produce 25% to 45% axial strain to open-cell po...

6.1 Chapter Summary In continuing efforts to understand urea phase connectivity in flexible polyurethane foams and its implications on physical properties, LiCl is used to alter the phase-separation behavior of slabstock foams. Comparisons are also drawn with plaque counterparts, which are prepared using the same polyol, isocyanate, and chain extender (water). LiCl is shown to alter the solid-s...

Al foams have found increasing applications in a wide range of structural and functional products, due to their exceptional mechanical, thermal, acoustic, electrical and chemical properties [1–3]. Al foam structures have densities only fractions of that of a solid structure and therefore have high specific strength and stiffness. They also have excellent properties for impact energy, vibration ...

Compressive mechanical properties of low-density, open-cell Zr-based bulk metallic glass foams processed by the salt replication method are investigated as a function of relative density and pore size in the ranges 14–28% and 150–355 lm, respectively. Scaling behaviors for strength and stiffness are discussed in the context of models developed for conventional metal foams, and appropriate modif...

Porous 85/15 poly (DL-lactide-co-glycolide) or PLGA foams were produced by the pressure quench method using supercritical CO2 as the blowing agent. The rate of CO2 uptake and CO2 equilibrium concentration in PLGA at different processing conditions were studied by performing sorption experiments. The effects of saturation pressure and temperature on average cell size and relative density of the ...

The optical, noncontact stereovision system and data analysis procedure are developed for the measurement of porous foams. The stereovision measurement system has demonstrated the capability to capture both the micro-scale features and the macro-scale shape of both the open-cell and closed-cell porous foams. A computational procedure, denoted as the grid method, is developed to identify represe...

A process has been developed for obtaining closed cell metallic foams using a ceramic foam precursor. In the present study, the major constituent of the ceramic foam precursor was iron oxide (Fe2O3), which was mixed with various foaming/setting additives. The mixture set rapidly at room temperature, stabilizing the foam generated by hydrogen release. The oxide foam was then reduced by annealing...

Directional freeze-casting – a process used to create foams with elongated, aligned pores applied so far exclusively for ceramics – is demonstrated for titanium foams. An aqueous slurry of <45 lm titanium powders was directionally solidified, resulting in a powder preform consisting of elongated, aligned dendrites of pure ice separated by interdendritic regions with high powder content. After f...