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Effects of Humidity and Elevated Temperature on the Density and Thermal Conductivity of a Rigid Polyisocyanurate Foam Co-Blown With CCI3F and CO2.


pdf icon Effects of Humidity and Elevated Temperature on the Density and Thermal Conductivity of a Rigid Polyisocyanurate Foam Co-Blown With CCI3F and CO2. (858 K)
Zarr, R. R.; Nguyen, T.

Society of the Plastics Industry of Canada's. Workshop on Long-Term Performance of Cellular Plastics, 3rd International. October 4-6, 1993, Ontario, Canada, 1-21 pp, 1993.

Journal of Thermal Insulation and Building Environments, Vol. 17, 330-350, April 1994.

Keywords:

polyisocyanurate foam; humidity; temperature; density effects; thermal conductivity; rigid foam; trichlorofluoromethane; carbon dioxide

Abstract:

Measurements of density and apparent thermal conductivity are presented for specimens of rigid polyisocyanurate (PIR) foam cut from a commercial insulation co-blown with trichlorofluoromethane (CCI3F) and carbon dioxide (CO2). Eight specimens, nominally 580 by 580 mm, were prepared from two boards (1.2 by 2.4 m by 50 mm) of foam laminated with permeable facers. Facers and excess foam were removed by sanding the specimens to a thickness of about 27 mm. Four specimens were placed in ambient conditions of 22 deg C and 40% relative humidity (RH). The other four specimens were each placed in one of the following environments: [1] 60 deg C and <10% RH; [2] 60 deg C and 40% RH; [3] 60 deg C and 60% RH; and, [4] 60 deg C and 75% RH. Measurements of apparent thermal conductivity were conducted at 24 deg C and a temperature difference of 22 deg C using a heat-flow-meter apparatus. Measurements were conducted over a period of 372 days at approximately 50-day intervals. Curves of specimen mass, volume, density, and thermal conductivity versus time are presented and the implications of changes in these properties are discussed.