The feasibility of incorporating ground recycled polyurethane (PU) foam into clay/polymer aerogels was demonstrated, and a range of compositions were prepared and characterized to determine the effect of variation in the formulations on density and mechanical properties of the resulting materials. This study followed a modified combinatorial approach. Initially, experiments were performed in water using either sodium exchanged montmorillonite or laponite clay, poly(vinyl alcohol) (PVOH) solution as the polymer binder, and the recycled PU foam. Freezing and freeze-drying the aqueous gels produced aerogels, which were characterized through density and mechanical testing, scanning electron microscopy, and thermal gravimetric analysis. The study was expanded by exploring alternative binder chemistries, including the use of an alginate polymer in place of the PVOH or adding a polyisocyanate as a crosslinking agent for PVOH. The effect of recycled PU foam content, clay type and level, and binder type and level on the mechanical properties of the aerogels were determined and will be discussed herein. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42586.

The structure/property relationships of polymer/clay aerogels interfused with uniformly distributed air bubbles were examined. Through the incorporation of a polyelectrolyte in a montmorillonite(MMT) clay solution, the viscosity was systematically changed by the addition of ions with different charges. The bubbles were achieved via high speed mixing and were stabilized through the use of the surfactant sodium dodecyl sulfate (SDS). As the charge of the ion increased from +1 (Na⁺ ions) to +2 (Ca²⁺ ions) to finally +3 (Al³⁺ ions), the modulus of the resultant aerogels increased. The foamed polymer/clay aerogels showed a reduction in thermal conductivity while retaining similar mechanical properties to unfoamed polymer/clay aerogels. The most promising composition was one which contained 5% MMT clay/5% poly(vinyl alcohol)/0.5% xanthum gum/0.5% SDS/0.2% Al₂(SO₄)₃·6(H₂O) possessing a density of 0.083 g/cm³, an average modulus of 3.0 MPa, and a thermal conductivity of 41 W/m·K. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39546.

Clay aerogels and poly(vinyl alcohol)/clay aerogels were prepared via an environmental friendly freeze-drying process. Both mechanical properties and microstructures of the clay aerogels and polymer/clay aerogels were correlated to the freezing conditions. The compressive moduli of these materials increased as the freezing temperature used to produce the aerogels was decreased. Scanning electron microscopic observations suggest that the morphological variations of clay aerogels can be explained by the mechanism of ice templating that produced these structures. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Laminates of polymer/clay aerogels and glass fabric sheets were prepared with varying epoxy adhesion application levels. A poly(amide-imide) and an epoxy (1,4-butanediol diglycidyl ether/2,6-diaminopyridine) were chosen as the two “foam core” polymers; both single-layered and double-layered glass fiber laminates were investigated. The adhesion between polymer clay aerogels and glass fibers was quantified using the T-peel method. The peel strength properties were found to increase as adhesive loading increased up to an optimal value, after which peel strength declines. Flexural and compressive testing of the laminates was also performed as a way of measuring mechanical strength. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

A series of polysulfone/phenyl trisilanol POSS nanocomposites were produced by melt blending by twin screw batch mixing. These materials were then injection molded, and their thermal, mechanical, and morphological properties were tested. The tensile properties of polysulfone were moderately compromised by the addition of phenyl TPOSS, because of the formation of large (∼ 1 μm) voided POSS aggregates. These domains however did cause the improvement of the impact resistance of the composites as described by the mechanism of crack pinning and bowing. Flexural properties remained essentially unchanged, which is attributed to the formation of an aggregate free-skin layer, which formed in the injection molded parts. Thermal behavior of the composites also remained largely unchanged due to the lack of POSS-polymer interactions on the molecular/chain segment scale. Initially, it was hypothesized that a high degree of POSS-polymer interactions would be present in these composited based on examination of their chemical structures. This however, was not the case as phase separation was clearly present. This work highlights the need for a better understanding of the prediction of POSS-polymer interaction. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Clay aerogels have many advantages as one of the lowest density family of materials current technology can provide; they possess very low thermal conductivities, high porosities, and high surface areas. Although the mechanical properties of native clay aerogels are rather low, incorporating water-dispersible polymers into the clay gel before they are processed into aerogel forms can easily produce more robust, low-density composites. Various processing modifications and additives can be employed to strengthen the aerogel material, but currently, the materials have some notable weaknesses in abrasion resistance, water absorption, and flexural properties. In this study, we employed a low-cost rubber coating material to quickly and efficiently address all three of these problems. After coating, the aerogels gained significant mechanical reinforcement, a 20-fold increase in flexural modulus and a 15-fold increase in yield stress, while exhibiting an increase of only 8% in the thermal conductivity. Improvements such as these can improve the commercial applicability of clay/polymer aerogels as thermal insulation materials. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

The thermal and oxygen transport properties of a series of thermoplastic polyurethanes (TPUs) based on 4,4′-methylene diisocyanate (MDI) and 1,4-butanediol (BD) as hard segments, and poly(tetramethylene glycol) (PTMG) or poly(butylene adipate) (PA) as soft segments, are studied. Oxygen permeabilities (P) of both polyester-based and polyether-based TPUs increase with decreasing hard segment fractions. Oxygen solubility (S) and diffusivity (D) can be derived from permeation curves. S correlates with the amount of excess free volume as determined by the difference between glass-transition and testing temperatures (i.e., the degree of super cooling) and decreases with the increased T_g in polyester-based TPUs. The intensity of low temperature gamma transition reflects the activation energy for D; the higher the intensity is, the lower D is annealed TPU samples exhibited higher oxygen permeabilities as well as lower storage moduli at room temperature, despite modest increases in overall crystallinity. Dedensification of the soft segment phase during annealing/crystalline phase growth is the most likely explanation for loss of mechanical and barrier properties after annealing as partially confirmed by Fourier transform infrared spectroscopy. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012