Crystallization and stress relaxation behaviors of UHMWPE/CNT fibers

Abstract

Crystallization and stress relaxation behaviors of ultrahigh molecular weight polyethylene (UHMWPE) doped with carbon nanotubes (CNTs) have been investigated by X-ray diffraction, differential scanning calorimetry (DSC) and single strand strength testing. Compared with UHMWPE, crystallinity of the UHMWPE/CNT composites significantly increases from 71.95 to 82.92% while crystallization activation energy decreases from 679.4 to 535.8 KJ/mol. CNTs as the nucleating agent changes the nucleation type of UHMWPE from homogenous to heterogeneous and accelerates the nucleation and growing of crystalline grains. Above crystallization changes also affect the mechanical properties of the UHMWPE/CNTs composites. Stress relaxation testing indicates that the relaxation stability of UHMWPE/CNT composites increases while the relaxation rate decreases. J. VINYL ADDIT. TECHNOL., 00:000-000,

Thermal and Structural Properties of High Density Polyethylene/Carbon Nanotube Nanocomposites: A Comparison Study

“…This can be attributed to the fact that the aspect ratio of the SWCNTs is higher than that of MWCNTs. As a result, MWCNTs deform the molecular chain orientation of the polymer, decreasing intermolecular interactions and subsequently decreasing the crystallinity [57,58]. This also causes SWCNTs to be more evenly dispersed in the polymer matrix, resulting in a higher impact on the polymer properties.…”

“…This acceleration in the grain growth explained the decrease in grain size (128 Å) due to the transform structure from coarse grains to fine grains, thus creating more grain boundary. This can be attributed to the fact that the pore size of the melted polymer matrix is determined as the CNTs are embedded in the polymer matrix [57]. The increase (11.9%) in HDPE crystallinity upon the addition of O-MWCNT resulted from changing the nucleation type of HDPE from the homogeneous to the heterogeneous nucleating, which led to accelerating the nucleation process and the formation of more crystalline grains [57].…”

“…This can be attributed to the fact that the pore size of the melted polymer matrix is determined as the CNTs are embedded in the polymer matrix [57]. The increase (11.9%) in HDPE crystallinity upon the addition of O-MWCNT resulted from changing the nucleation type of HDPE from the homogeneous to the heterogeneous nucleating, which led to accelerating the nucleation process and the formation of more crystalline grains [57]. This acceleration in the grain growth explained the decrease in grain size (128 Å ) due to the transform structure from coarse grains to fine grains, thus creating more grain boundary.…”

“…This acceleration in the grain growth explained the decrease in grain size (128 Å ) due to the transform structure from coarse grains to fine grains, thus creating more grain boundary. This can be attributed to the fact that the pore size of the melted polymer matrix is determined as the CNTs are embedded in the polymer matrix [57].…”

Polyethylene/TiO2 Medical Tube with Comprehensive Mechanical Performances via Bio‐Mimic Multiscale Helical Structures

“…As well demonstrated [15–18], the performances of the polymeric products are not only derived from the chemical structures but also drastically depend on the crystalline structures and morphology formed in the processing procedure. Enlightened by nature [19–21], helical aligned structure widely existing in crustacean exoskeletons and wood tracheid offers an inspiring clue to solve the pre‐mentioned problems.…”