Refractometric determination of second‐order transition temperatures in polymers. IV. Butadiene‐acrylonitrile copolymers

The second‐order transition temperatures ( T m ) for foruteen commercially available butadiene‐acrylonitrile copolymers with 18–50% acrylonitrile have been determined refractometrically and found to be somewhat lower than the corresponding brittle temperatrues ( T b ). The data show a linear relation between T m and acrylonitrile content.