S cul pt ors ▁from ▁Missouri <0x0A> </s> ▁Samuel ▁Em m ett ▁Hor ne ▁Jr . ▁( J uly ▁ 2 6 , ▁ 1 9 2 4 ▁– F ebru ary ▁ 4 , ▁ 2 0 0 6 ) ▁was ▁a ▁research ▁scient ist ▁at ▁B . ▁F . ▁Good rich ▁noted ▁for ▁first ▁synth es izing ▁c is - 1 , 4 - poly is op rene , ▁the ▁main ▁polym er ▁contained ▁in ▁natural ▁tree ▁rub ber , ▁using ▁Z ieg ler ▁catal ysis . ▁Ear lier ▁attempts ▁to ▁produce ▁synth etic ▁rub ber ▁from ▁is op rene ▁had ▁been ▁un success ful , ▁but ▁in ▁ 1 9 5 5 , ▁Hor ne ▁prepared ▁ 9 8 ▁percent ▁c is - 1 , 4 - poly is op rene ▁via ▁the ▁s tere os pec ific ▁polym er ization ▁of ▁is op rene . ▁The ▁product ▁of ▁this ▁reaction ▁diff ers ▁from ▁natural ▁rub ber ▁only ▁slightly . ▁ ▁It ▁contains ▁a ▁small ▁amount ▁of ▁c is - 1 , 2 - poly is op rene , ▁but ▁it ▁is ▁ind ist ingu ish able ▁from ▁natural ▁rub ber ▁in ▁its ▁physical ▁properties . ▁ ▁The ▁importance ▁of ▁Hor ne ' s ▁development ▁of ▁synth etic ▁poly is op rene ▁and ▁poly but ad iene ▁is ▁readily ▁seen ▁in ▁the ▁production ▁of ▁these ▁polym ers . ▁In ▁ 2 0 0 8 , ▁global ▁production ▁of ▁poly but ad iene ▁was ▁ 2 , 0 4 2 ,