Raman Spectroscopic Study of High-density Polyethylene during Tensile Deformation

Abstract

Raman spectroscopic analyses have been applied for various materials, such as nanoparticles and polymer composites [10-16]. Rheo-optics which is methods of simultaneous measurements of spectroscopic observation and mechanical testing are powerful

Rheo‐Raman Study of Isotactic Polypropylene Under Tensile Deformation

“…In the post‐yielding or the highy‐strained region, Δν 809 shows larger bule shift than Δν 1035 , in accordance with the peak shift factors in Table , implying the load sharing of the crystalline chains is isotropic. On the other hand, the peak shift Δν 998 of the 998 cm −1 band assigned to the CH 3 rocking mode increases after the first yield point and shows a maximum around the second yielding point, suggesting that the compression stress is applied in the interchain direction in the yielding region as observed for HDPE . After the yielding region, Δν 998 gradually decreases to zero, suggesting that the compression stress is released due to the onset of the molecular orientation.…”

“…As the rheo‐optical methods, infrared (IR) dichroism and X‐ray scattering have been applied for evaluating the effect of the molecular orientation on the mechanical properties . Recently, Raman spectroscopy has been utilized in various research fields owing to several advantages; the skeletal vibrations of the CC stretching modes are strongly Raman‐active, the orientation distribution of the molecular chain is determined from the polarized Raman spectra and the spectroscopic method is directly applied to thick specimen without pretreatment…”

Rheo‐Raman spectroscopic study of microscopic deformation behavior for ultra‐low‐density polyethylene

“…Real‐time changes of the polarized Raman spectra during tensile deformation were measured by the rheo‐Raman spectroscopic system combined with a small tensile tester . Double‐notched specimens with width 4 mm and gauge length 2 mm for tensile tests were cut from ULDPE sheet of 1 mm thickness.…”

“…In addition the orientation distribution function (ODF) can be calculated from the polarized Raman spectra . We have developed a rheo‐Raman spectroscopic system with a tensile machine and elucidated deformation mechanisms at molecular level such as the load sharing of the molecular chains and the molecular orientation under uniaxial stretching …”

Raman Spectroscopic Study of Microscopic Deformation Behavior of Crystalline Polyolefin Solids

“…(Color online) Raman spectra of HDPE (circles) around (a) 1100 cm ¹1 and (b) 1400 cm ¹1 . The black line represents the fitting curve with a sum of Voigt functions (blue lines)25) .…”