Density Measurement and Pore Volume Measurement Absolute density measurement by gas pycnometry Bulk density measurement by mercury pycnometry Total Pore Volume measurement by combination The   calculation   of   density   seems   straightforward,   Density   =   Mass   /   Volume.   However,   depending   on   the   method   used   to   measure   volume   significantly   different   density   values   can   be   obtained   for   a sample,   depending   on   the   inclusion   or   exclusion   of   open   sample   pores.   The   distinctly   different density values, may independently have profound effects on the functionality of the material. Bulk   density ,   also   termed   envelope   density ,   includes   the   volume   of   all   pores   within   the   sample. At MCA this is measured by mercury displacement using our Micromeritics AutoPore V instrument. This   is   available   both   as   a   single   analysis   option   or   incorporation   to   a   full   mercury   porosimetry analysis.   This   technique   allows   for   precise   control   over   the   pressure   at   which   density   is   calculated and   therefore   ensures   that   samples   are   fully   enveloped   in   mercury,   yielding   highly   accurate bulk density values. The   full   mercury   porosimetry   analysis   also   includes   the   skeletal   density    of   the   sample   together with pore size, volume and area distributions.   Absolute   density ,   also   termed   true   density    is   measured   by   gas   displacement,   usually   applyi ng helium,   using   a   Micromeritics   AccuPyc   instrument.   The   volume   of   open   pores   is   excluded   from   the calculation of density and so the absolute density represents that of the solid material alone. Some    materials    may    be    susceptible    to    helium    entrapment,    such    as    activated    carbon    based materials. Where this is a concern alternative gases may be applied, for example nitrogen or argon. A   variety   of   sample   cells   are   available   allowing   for   most   solid   sample   forms   to   be   analysed,   even   i n low   quantity.   The   technique   also   allows   for   the   calculation   of   closed   porosity   (pores   with   no   access to    the    outside    of    the    sample)    through    combination    with    theoretical    density    values.    This    is particularly useful for assessing foam and constructional materials. More information and a demonstration is given on our YouTube  channel. Total   Pore   Volume   (TPV)   can   be   calculated   by   the   combination   of   bulk   density   and   absolute density    values   and   we   offer   this   as   a   separate   analysis   option.   The   total   pore   volume   of   a   sample   is reported together with the two density values are reported for this analytical option.