Heat Capacity of the White Pine Biocarbon Preform and the Related Biocarbon/Copper Composite

This paper reports on measurements in the 80–300-K temperature interval of the heat capacity at constant pressure C_(p)(T) of high-porosity amorphous white pine carbon preforms (biocarbon) prepared by pyrolysis (carbonization) at T_(carb) = 1000 and 2400°C in an argon flow. The dependences C_(p)(T) for biocarbon/copper composites based on the carbon preforms obtained have also been determined. It is shown that the mixture rule holds for the composites, i.e., that C_(p)(T) of the composite is a sum of the heat capacities of the constituent materials taken in the corresponding ratios. Phonon mean free paths for the white pine carbon preforms prepared at T_(carb) = 1000 and 2400°C have been calculated and used to estimate the size of the nanocrystallites contributing to formation of the carbon frameworks of these preforms.