of acrylonitrile chloroprene natural latex were tested to determine the tensile strength of films thereof referring to the figure a comparison of the tensile strength for the 300 modulus of each sample is made the 300 modulus of sample 1 as shown at 10 was substantially less than the 300 modulus of sample 2 as shown at 20 both were less than the 300 modulus of sample 3 shown at 30 a tensile strength value 50 of sample 2 however is substantially in line with a tensile strength value 40 of sample 1 but substantially greater than a tensile strength value 60 of sample 3 this indicates that an optimum amount of acrylonitrile occurs between 20 wt and 40 wt sample discs of material were folded twice to generate a stress point the sample discs were then placed into an ozone chamber operating at 25 35 pphm ozone concentration the samples were checked after every hour and assigned a value 0 4 in 0 5 increments based on the degree of wear of the sample an assigned value of 0 indicated that the sample experienced some whitening but no cracks and no damage was visible a value of 1 indicated that small microscopic cracks were visible under magnification but.