A solid-state chemical reaction occurs when a solvent cast film of a b
lend of masticated natural rubber and chlorinated natural rubber is he
ated in the presence of air at 150 degrees C. The thermal behavior of
solvent cast films of chlorinated natural rubber, masticated natural r
ubber, and a 1 : 1 w/w blend (2% w/v in xylene) of these two polymers
has been studied using differential scanning calorimetry, infrared spe
ctroscopy, scanning electron microscopy, and nuclear magnetic spectros
copy. The results suggest that carbonyl groups are incorporated into t
he blend on heating and that the vinyl functionality of the isoprene u
nits is modified during this apparent oxidation. seating for 2 h at 15
0 degrees C results in a material that no longer contains the rubber-l
ike cis-1,4-polyisoprene units. (C) 1997 John Wiley & Sons, Inc.