To minimize these performance deficiencies in materials used to limit air permeability, {HEAD ~ special material formulations} have been developed that comprise, preferably, {TAIL ~ an amorphous polyurethane based elastomer/rubber alloy} 
comprise
To minimize these performance deficiencies in materials used to limit air permeability , { HEAD ~ special material formulations } have been developed that comprise , preferably , { TAIL ~ an amorphous polyurethane based elastomer / rubber alloy }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL