{HEAD ~ The synthetic fiber component}, on the other hand, retains {TAIL ~ its mechanical strength} even while the wood pulp fiber component loses its strength 
retains
{ HEAD ~ The synthetic fiber component } , on the other hand , retains { TAIL ~ its mechanical strength } even while the wood pulp fiber component loses its strength
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH