Porous Polystyrene Foam Produced at Supercritical Conditions

Self Cite

This work examines the foam density, average cell sizes, and cell structure of four polystyrene (PS) blended with calcium carbonate (CaCO 3 ) or low density polyethylene (LDPE) at various ratios. The PS/CaCO 3 and PS/LDPE are foamed by carbon dioxide (CO 2 ) under supercritical conditions. CaCO 3 and LDPE can strongly influence the foam density, average cell sizes, and cell structure of PS foams. Based on the result of PS/CaCO 3 foams and PS/LDPE foams, the thermal conductivity of large porous PS foams as core materials used in vacuum insulation panels (VIPs) is further studied. Large porous PS foams are produced by the mixture of CO 2 and fluorocarbon or the mixture of CO 2 and nitrogen (N 2 ) as foaming agents. The content of open-cells in PS foams is affected by materials, foaming temperatures, and foaming agents. A higher content of open-cells in a porous PS foam can lead to a lower and more stable thermal conductivity of VIPs.

mentioning

confidence: 99%

“…Figure13. Thermal conductivity of VIPs using PS/LDPE with fillers foams as core materials at various foaming temperatures and CO 2 /fluorocarbon as a foaming gas.…”

mentioning

confidence: 99%

Polystyrene Foams as Core Materials Used in Vacuum Insulation Panel

Wong

Hung

2008

Self Cite

“…These excellent properties broaden the application of polymer foams in wide range of areas, such as automobile industry, packaging, and thermal and sound insulation, etc. However, the majority of the polymer foams used in different areas are derived from non-renewable fossil fuels such as polypropylene (PP), 1 polystyrene (PS), 2 polyurethane (PU) 3 and polyvinyl chloride (PVC). 4 Because of the increasing concerns over the environmental influence and sustainability of petroleum-based polymer materials, biodegradable polymer foams have been attracting great attention from both industrial and academic areas.…”

Section: Introductionmentioning

confidence: 99%

Foaming behavior of poly(lactic acid) with different D-isomer content based on supercritical CO₂-induced crystallization

Chen

Yang

Qunshan

et al. 2020

Using supercritical carbon dioxide (sc-CO2) as a physical foaming agent, the effect of sc-CO2 on the formation of crystalline domains and subsequently on the foaming behaviors of the two grades of PLA with different D-isomer content were investigated in a wide foaming temperature range. The PLA’s final crystallinity is significantly increased with decreasing annealing temperature and by reducing the D-isomer content. Cellular structure results show that not only the crystallinity but also the crystalline morphology play an important role in cellular structure. A novel spherulite morphology including ringless and ring-banded morphology in the same spherulite was formed at lower foaming temperature, as a result, some entities were nonuniformly distributed in the PLA foams. Uniform and closed cellular structure were obtained when only the ring-banded spherulites were formed. An opened and interconnected cellular structure is tended to be formed because of the synergistic effect of high temperature and plasticization of CO2. Based on the crystallinity and morphology, a suitable foaming window as a function of temperature is proposed. It is found that PLA with 4.1% D-isomer content had much broader suitable foaming window range to produce homogeneous cellular structure.

“…The previous study [16] was associated with porous PS foam fabricated by a blend of PS with CaCO 3 . The primary goal of the article is to study the processing conditions to make a low foam density for PS/PE foam and further investigate the production of porous PS/PE with fillers foams.…”

Section: Introductionmentioning

confidence: 99%

Effect of Low Density Polyethylene on Polystyrene Foam

Wong

Tsai

Ying

et al. 2006

Self Cite

This work examines the foam density of polystyrene (PS) blended with low density polyethylene (LDPE) at various ratios, and the thermal conductivity of vacuum insulation panels (VIPs) using PS/PE with filler foam as core materials. The experimental results indicate that LDPE strongly influences the foam density of PS/PE foam and the content of open-cells in PS/PE with filler foam. A higher content of open-cells in PS/PE with filler foam can lead to a lower thermal conductivity of VIP.