The excellent barrier properties of high nitrile plastics offer potential as materials for use in packaging of carbonated beverages and oxygen-sensitive foodstuffs. However, due to the viscoelastic nature of thermoplastics, improvement in creep resistance is essential for pressurized containers, such as plastic beer and beverage bottles, to resist the dimensional increases with time. Biaxial orientation and annealing are both effective in reducing the creep rate of pressurized plastic beverage containers.