Blends of two or more polymers may be desirable in some cases and the polymers selected will depend at least to {HEAD ~ a certain extent} on the purpose to which {TAIL ~ the material} is to be put 
Blends of two or more polymers may be desirable in some cases and the polymers selected will depend at least to { HEAD ~ a certain extent } on the purpose to which { TAIL ~ the material } is to be put
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH