The structure of crazing formed as a result of deformation in polyethyleneterephthalate at various temperatures

The structural evolution of high-density polyethylene during crazing in liquid medium

“…However, assuming that, at a tensile strain of 100-200%, the thickness of a fibril is equal to the diameter of a pore, the ''pore width + fibril diameter'' values determined by AFM may be used to estimate the pore width (pore diameter) in HDPE as a value of about 6-13 nm at tensile strains of 100% and 200%, respectively. The similar fibril diameters and pore widths (about 8-10 nm) were also obtained by SAXS for crazed HDPE [51]. In work [52] the parameters of the fibrillar-porous structure of HDPE deformed by the crazing mechanism (that is used in this work) were determined by the pressure-driven liquid permeability method.…”

Cold Crystallization of Glassy Polylactide during Solvent Crazing

“…In this calculation, we assumed that the concentration of fibrils in craze ( c ) is the inverse of the extension ratio of fibrils (λ), that is, c = 1/λ. Usually, λ corresponds with a good accuracy to the natural draw ratio in the neck. , The obtained values show that the natural draw ratio in the neck of PLA is about 3.5, and the concentration of fibrils is 0.29. The calculated diameter of PLA fibrils in crazes appeared to be nearly 12 nm, and the diameter of pores is about 15 nm.…”

“…For example, it was previously shown − that thin films of various glassy polymers (polystyrene and poly­(methylmethacrylate)) are characterized by decreased T g value by a few tens of degrees. Furthermore, it was suggested , that mobility of polymer chains at the craze–bulk polymer boundary was strongly enhanced by the presence of the triaxial tensile stress at the base of each craze fibril. Therefore, the T g of PLA in fibrils could be reduced to room temperature.…”

“…Furthermore, at high tensile strains (higher than 300%), the DSC thermogram showed the formation of a crystalline structure of PLA with a degree of crystallinity of about 35%. It is worth noting that the orientation drawing of polyethylene terephthalate (PET, which has properties similar to PLA) to high tensile strains (300–400%) under same conditions also results in the development of the crystalline structure. − …”

Micromechanical Processes in PET/PC Multilayered Tapes: High Voltage Electron Microscopy Investigations

“…Some authors [11,12] have reported that amorphous and crystallized PET films usually undergo fibrillated crazing. However, shear-bands were also found elsewhere.…”