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Heat capacity of polypropylene composite at high pressure and temperature
Author(s) -
Hsieh K. H.,
Wang Y. Z.
Publication year - 1990
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760300808
Subject(s) - polypropylene , materials science , heat capacity , composite material , thermal diffusivity , composite number , differential scanning calorimetry , thermal conductivity , volume (thermodynamics) , fiber , thermodynamics , physics
The heat capacities of isotactic polypropylene and its composite with glass fiber have been measured at high pressure, up to 7 MPa, in the melt state by high pressure differential scanning calorimetry (HPDSC). The values also have been calculated from the data of specific volume ( V ) measured by dilatometry and thermal conductivity (κ) and thermal diffusivity (α) measured by a compensating hot wire method. The values of the heat capacity measured from HPDSC are consistent with those from the calculation method. The heat capacities of molten polypropylene and its composite increase linearly with temperature at a constant pressure and decrease with pressure at a constant temperature. It was found that the heat capacity of polypropylene is insensitive to molecular weight. The heat capacities of molten polypropylene composites are found to be predicted by an additive rule from the weight fractions of heat capacities of polypropylene and glass fiber.