Polyethylene martensitic transformations

Stress induced martensitic transformation is a transformation firom one ciystallographic form to another form and associated with a displacement of chains to new positions in the new crystallographic ceU in order to acconunodate the deformation. An example of martensitic transformation firom orthorhombic to monoclinic form was found in oriented polyethylene with well defined texture subjected to uniaxial compression. Martensitic transformation was also found in other polymers in poly(L-lactic acid) [119] and in nylon 6 with the a-form transforming to the 7-form [120,121]. 

Young R J and Bowden P B (1974) Twinning and martensitic transformations in oriented high-density polyethylene, Phil Ma 29 1061-1073. 

Martensitic transformations have not been widely reported in polymers, but an important one occurs on the deformation of polyethylene. The normal crystal structure of both solution-grown single crystals and melt-crystallized polymer is orthorhombic, but after deformation extra Bragg reflections are found in diffraction patterns and these have been... 

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