Thermal analysis of polymeric sheathing materials for fibre optic communication cables

On the basis of the DSC and TGA results reported, the three commercial sheathing material were characterized as follows. The thermoplastic was found to be a linear low density polyethylene, containing ~5% carbon black as a UV stabilizer. The organic elastomer was identified as a cross-linked ethylene based copolymer, containing ~5% carbon black and 55% ATH as fillers. The behaviour of the silicone rubber was consistent with a material of this type. However, no phase transitions were evident and the decomposition behaviour and residue chemistry of these compounds is such that no estimate of filler loading could be made. From the thermal studies (DSC, TGA and laser ablation) it can be concluded that the resistance of the LLDPE to surface discharge activity should be considerably worse than that of the other two materials considered