Synergistic effect of polyurethane‐coated carbon fiber and electron beam irradiation on the thermal/mechanical properties and long‐term durability of polyamide‐based thermoplastic composites

Abstract

To attain thermoplastic polymer composites with enhanced thermal and mechanical properties as well as long‐term durability, in this study, polyurethane‐coated carbon fiber (CF) and electron beam (EB) irradiation are adopted as an effective reinforcing filler and efficient crosslinking process, respectively. For this purpose, polyamide 6 (PA)‐based composites with different CF contents of 1–10 wt% were fabricated through melt‐compounding and compression molding, and then irradiated with various EB doses of 50–200 kGy. The SEM and FT‐IR data reveal that CFs are well dispersed in the PA matrix with excellent interfacial adhesion via specific intermolecular interactions, which are even enhanced for the composites with crosslinked PA matrices after the EB irradiation. As the result, the thermal stability (initial decomposition temperature and residue at 800°C) and dynamic mechanical properties of PA/CF composites increased noticeably with increasing the CF content and EB irradiation dose. The initial storage modulus of 1.90 GPa for neat PA at 30°C was improved significantly to 2.94 GPa by 10 wt% CF addition and to 4.67 GPa by 200 kGy EB irradiation. In particular, the long‐term mechanical properties of PA/CF composites, which were evaluated using a stepped isothermal method based on the time–temperature superposition principle, were found to be highly enhanced by the synergistic effect of CF filler reinforcement, EB‐induced PA matrix crosslinking, and improved interfacial adhesion.

Interfacial Engineering Methods in Thermoplastic Composites: An Overview

“…Kim et al [ 121 ] used PU polymer sizing and EB irradiation to increase the CF and PA6 matrix interfacial bonding. CF coated with PU sizing agent was melt compounded with PA6 pellets and compression molded to form CF/PA6 composites.…”

Short aramid fiber reinforced thermotropic liquid crystalline polyester composites: Fabrication, thermal, and mechanical properties

“…On the other hand, the stepped isothermal method (SIM) compensates for the shortcoming of the traditional TTS test and needs only one specimen to be tested at various step-up temperature levels. [45][46][47][48] To examine the long-term durability of mechanical properties, the elastic storage moduli can be measured as functions of temperature and frequency by adopting the SIM with the assumption that the strain is a thermal activation process. Thus, based on the TTS principle, storage modulus values measured as a function of frequency over a short period at various temperatures need to be horizontally shifted so that they fit well with the long-term mechanical durability curve measured along the axis of frequency through the shift factor (a T ), which leads to the creation of a frequency-dependent master curve at a reference temperature.…”

Changes in the Electrophysical Parameters of Nanomodified Elastomers Caused by Electric Current’s Passage

“…Conductive composites based on organosilicon elastomers (silicones) [ 22 ] may have a functional feature associated with self-regulation of the heating temperature [ 23 ]. Studies related to the effect of MWCNTs on heat release in a flexible nanomodified elastomer are presented in the work and it was found that the heat release power can be represented in the form of regression equations, where there is a dependence of heat release on temperature, applied tensile strain and electrical heating [ 24 ].…”