TekNational, Inc.
Tek-Sil® GP2X Series
If you need a gap filler with higher thermal conductivity, Tek-Sil® GP2X is rated at 2.8 watt/mk compared to 1.5 watt/mk for the standard "GP" material.  This material is presently available in six thicknesses. 
GP2X SeriesUnitGP2X-20GP2X-40GP2X-79GP2X-98GP2X-118GP2X-197
Thicknessmm0.5 +/-0.11.0 +/-0.22.0 +/-0.32.5 +/-0.33.0 +/-0.35.0 +/-0.3
Widthmm200200200200200200
Lengthmm300300300300300300
Thermal Resistance°Cin²/W0.761.17
ColorvisualGray
Thermal Conductivitywatt/m-k2.7
Volume ResistivityMohm·m2.5x104
Withstand VoltagekV/mm·AC15
Specific Gravitygr/cm³2.7
HardnessShore OO53
Elongation%64
CompressionKgf/in²@10%2818
50% sustain after 1 min19672
Continuous Use°C-60° to +200°
Flame RetardanceUL 94VV-0