The results showed the crystallinity of the modified PET decreased with the increase of the content of NPG, but the heat shrinkability was improved obviously.

• 无定型区增大，获得了在通常情况下不能结晶的PET无定型材料，从而使改性PET薄膜在拉伸时保持较高的取向度，并在高于其T(下标g)时发生解取向热收缩；