Laser ablation and thermal decomposition studies of fibre opticcable sheathing materials

摘要

Three commercial fiber optic sheathing compounds (a thermoplastic,a filled organic elastomer, and a silicone rubber) and three modelsystems (a polyethylene, an ethylene-propylene rubber, and analuminum-hydroxide-filled elastomer) were investigated. The thermalproperties of the materials were studied by thermogravimetric analysis(TGA) and differential scanning calorimetry (DSC). From the thermalstudies (DSC, TGA, and laser ablation) it is concluded that theresistance of the linear low-density polyethylene to surface dischargeactivity should be considerably worse than that of the other twomaterials considered, a result that is consistent with serviceexperience. At low temperatures this stems from the absence ofcross-links which, in the other two materials, serve to restrict flow.Where temperatures reach much higher levels, the presence of inorganicfillers becomes an important factor in resisting thermal erosion. Thus,on the basis of the results obtained, the performance of the siliconematerial should be superior to that of the ethylene-based elastomer.Laser irradiation constitutes a useful means of inducing localizedheating