Glass bubble reinforced polyurethane foams with high mechanical strength for cryogenic temperature insulation

Abstract

In this study, glass bubble (GB) is added to polyurethane (PU) foams at different weight ratios—0, 0.25, 0.5, 0.75, and 1 wt% —to investigate the changes in the mechanical and thermal properties of the foam. By conducting several tests and measurements, the density, cell morphology, compressive strength, and thermal conductivity of the foam are studied. In particular, the effect of GB additives is examined by conducting compression tests at various temperatures (−163, −100, −40, and 20°C). Scanning electron microscopy and X‐ray microscope reveal that the foams exhibit higher stability below 0.5 wt%, which improves the thermal performance. On the other hand, the compressive strength of the foams increases for all weight ratios of GB, and it increases sharply at 0.75 wt%. In addition, the chemical interactions and the dispersion of additives in the PU matrix are investigated through Fourier transform infrared and X‐ray diffractions analysis. It is found that the synthesis of PU foams with GB nanoparticles is an efficient method for improving the mechanical properties and insulation performance of the foam for LNG insulation technology.

Collapse pressure measurement of single hollow glass microsphere using single-beam acoustic tweezer

“…Hollow glass microspheres (HGMs) meet these requirements; they are composed of soda-lime-borosilicate glass, which is spherical and hollow, and has a single, thin outer wall (<1 μm thick). They are widely used in non-medical applications such as oil expansion [16] , thermal insulation [17] , and weight reduction [18] . In the medical field, HGMs are utilized for cell sorting or cell wall destruction owing to their rigidity [19] , [20] .…”

“…In the medical field, HGMs are utilized for cell sorting or cell wall destruction owing to their rigidity [19] , [20] . HGMs do not dissolve and have high collapse pressure and low thermal conductivity [16] , [17] , [18] . Because they are brittle, HGMs produce clear collapse patterns when ruptured.…”