PMR Analysis of Poly isobutylene-co-3-Pinene

Physical appearance White White White White Cohesive Retract- Brittle 

Sulfur vulcanizability Vulcanizable Vulcanized to strong rubber Vulcanized to strong rubber 

Tensile strength, kg/cm 35 Uncertain because of slippage lower limit 211 240 

Ozone resistance determined (see text for details) Resistant Resistant (stress-strain- unaffected) 

Spectrum of the copolymer to fully crowded gem-dimethyl sequences, i.e., isobutylene-isobutylene or ii for brevity, sequences. Poly(jS-pinene), a molecule that contains uncrowded gem-dimethyl groups, shows a resonance band at 0.85. On the basis of this, we assigned the band appearing at 0.8 5 in the spectrum of the copolymer to uncrowded gem-dimethyls indicating a P-pinene unit that is followed by another j3-pinene unit i.e, flS sequences. The central band at 1.05 of the three partially unresolved bands in the spectrum of the copolymer is a new gem-dimethyl band 

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