Some new aspects of fracture mechanics of polymers

It is shown that negative Linear thermal expansion coefficient, evolution of heat under stretching and positive weight changes as a result of fracture of an oriented polyethylene may be associated with crystalline structure characterized by c-axis orientation of crystallites and positive Linear thermal expansion coefficient, absorption of heat under stretching and weight losses as a result of fracture of oriented polyethylene may be associated with crystalline structure characterized by a-axis orientation of crystallites. Relativistic mechanisms of internal energy and weight changes during processes of deformation and fracture are discussed.