Role of Melt Plasticizing Temperature in Morphology and Properties of PE100 Pipes Prepared by a Rotational Shear System

Abstract

To increase the maximum internal pressure that a polyethylene (PE) pipe can withstand, a novel rotational shear system (RSS) was constructed in this study to fabricate PE pipes with enhanced hoop strength by applying hoop shear on the pipes using a rotational mandrel. The microstructure and morphology with the influences of melt plasticizing temperature on PE pipes processing under rotational shear were investigated indirectly using small-angle X-ray scattering and wide-angle X-ray diffraction (SAXS/WAXD) measurements. In the SAXS patterns, equatorial streaks and meridional scattering peaks were clearly observed in all three samples prepared at different melt plasticizing temperatures, 215, 235, and 255 °C. Their presence indicated that shish–kebab crystals form in rotational shear. Compared to those at the low melt temperature, the increase in the melt temperature enhanced the amount and the dimensions of shish formed. However, the shish also relaxed faster at the high melt temperature. This behavior was attributed to the enhancement of the molecular chain’s athletic ability. The hoop tensile strength and the heat resistance of the pipes peaked at the melt plasticizing temperature of 235 °C, 75.2 MPa, 102.4 °C, up 1 MPa, 0.2 °C (compared to the 215 °C) and 7.8 MPa, 3.2 °C (compared to the 255 °C). The axial strength increased with an increase of melt plasticizing temperature. However, the increase of melt plasticizing temperature worsens the inherent good tensile toughness of PE100 pipes as the axial elongation at break decreases.

Achieving High-Performance Green Composites from Pineapple Leaf Fiber–Poly(butylene succinate) through Both Fiber Alignment and Matrix Orientation across the Thickness

“…Therefore, it can be deduced that the PBS prepreg possesses a shish-kebab structure. Similar thermal behavior can be observed in isotactic polypropylene ( i PP) 32 and polyethylene 33 , 34 with a shish-kebab structure. This observation also confirms that the method use is effective enough to cause nuclei (shish or chain-extended core) to develop from chains aligned under elongation or shear flow.…”

Effect of Cellulose Nanocrystals and Hot Stretching on Shish–Kebab Structures of High-Density Polyethylene

“…Due to the implementation of hot stretching and the addition of CNC, there are differences in the size of the crystals, which will be proven in the following chapters. Thinner and imperfect crystals will exhibit slightly lower peaks on the DSC curve, while larger crystals will exhibit larger peaks. , …”

“…Place the sample shear layer in the center of the scattering hole in the sample holder to obtain shear layer data. All SAXS modes are preprocessed to correct for the effects of background scattering, air scattering, and synchrotron beam fluctuations, they are analyzed by Fit2D software, , and the resulting data are processed by software such as Foxtro and origin to obtain a two-dimensional (2D)-SAXS image.…”

“…Thinner and imperfect crystals will exhibit slightly lower peaks on the DSC curve, while larger crystals will exhibit larger peaks. 33,41 The increase of melting point is affected by three factors. First, due to the addition of CNC, which acts as a nucleation site to promote the formation of more shish−kebab structures, it results in an increase in the energy required for melting.…”