The molecular mechanism of shrinkage of polyethylene terephthalate

Micromechanical modelling of reversible and irreversible thermo-mechanical deformation of oriented polyethylene terephthalate

“…Such behaviour can be classified as a shape-memory effect, where the partial recovery of the original shape is a result of increased molecular mobility above T g and the driving force is due to the tendency of the structure to increase its entropy by relaxing the oriented conformation [8]. In oriented amorphous PET there is evidence that the molecular origin of this process lies in a redistribution of the rotational isomers along the polymer chains, leading to their coiling [9].…”

Influence of fibre shrinkage and stretching on the mechanical properties of self-reinforced poly(ethylene terephthalate) composite

“…3 Temperature heavily influences the mechanical properties for polymers, and oriented polymers shrink at elevated temperatures leading to changes in microstructure when returning to the preferred isotropic microstructure. [4][5][6][7][8] This results in a permanent decrease in stiffness and strength. 9 Self-reinforced polymer composites (SrPc) are materials that have reinforcement and matrix made out of one and the same type of polymer, where the reinforcement can be thermoplastic fibres or tapes that have oriented microstructure.…”

“…3 Temperature heavily influences the mechanical properties for polymers, and oriented polymers shrink at elevated temperatures leading to changes in microstructure when returning to the preferred isotropic microstructure. 4–8 This results in a permanent decrease in stiffness and strength. 9…”

Shrinkage Behavior of Orientedpoly(ethylene Terephthalate)

“…Murthy et al [14] have discussed the role of an oriented amorphous phase in determining dimensional stability. Pakhomov et al [15] studied the kinetics of shrinkage as a function of temperature and external stress. They employed first order reaction kinetics to describe the shrinkage process.…”