cell design for thermal management applications graphite fiber is combined with thermoset and or thermoplastic polymers to yield high thermal conductivity composites graphite fibers using a petroleum pitch precursor instead of a pan precursor is preferred since pitch precursor graphite fibers have superior mechanical thermal and electrical performance compared to pan based graphite fibers however the cost of such fibers precludes their use in many applications in addition the smallest pitch precursor yams currently available are approximately 3850 denier and therefore only relatively thick fabrics can be woven from them the present approach is to obtain pitch precursor yarn 30 at an intermediate stage in its processing i e at the thermoset stage prior to carbonization or graphitization the yarn 30 is then stretch broken by any means suitable for the purpose stretch breaking as aforesaid is a process that starts with high denier yams and reduces them to low denier yarns 32 by a process whereby the multiple filaments within the yarn bundle are randomly broken and drawn to a lower denier following stretch breaking the resulting intermediate product which is in the form of a ribbon 34 can be processed in a number of ways including being held by a serving yam after being stretch broken and spun to yield various textile products the ribbon 34 can be further reduced and is formed in a small yam of an equivalent filaments count between 200 and 500 for example the original tow may be reduced to approximately 500 denier a reduction of approximately 8 1 this low denier yam is then woven into a thin smooth surface fabric and then subjected to two consecutive heat treatment processes alternatively the yarn can be knitted or braided the heat.