Thermomechanical Degradation of Polyetherimide (PEI) by Friction-Based Joining and the Effects on Quasi-Static Mechanical Strength of Hybrid Joints

Author(s)

Sonego, M. ^{[1, 2]} ; Abibe, A. B. ^[2] ; Canevarolo Jr, V, S. ; Bettini, S. H. P. ^[3] ; dos Santos, J. F. ^[2] ; Canto, L. B. ^[3] ; Amancio, S. T. ^[4]

Affiliation

^[1] Univ Fed Sao Carlos, Grad Program Mat Sci & Engn, Rodovia Washington Luiz Km 235, BR-13565905 Sao Carlos, SP - Brazil

^[2] Helmholtz Zentrum Geesthacht, Inst Mat Res, Solid State Joining Proc, Mat Mech, Ctr Mat & Coastal Res, Geesthacht - Germany

^[3] Canevarolo Jr, Jr., S., Univ Fed Sao Carlos, Grad Program Mat Sci & Engn, Rodovia Washington Luiz Km 235, BR-13565905 Sao Carlos, SP - Brazil

^[4] Graz Univ Technol, BMVIT Endowed Professorship Aviat, Inst Mat Sci Joining & Forming, Graz - Austria

• Document type: Journal article
• Source: INTERNATIONAL POLYMER PROCESSING; v. 34, n. 1, p. 100-110, MAR 2019.
• Web of Science Citations: 0

Abstract

This study investigated quantitatively the thermomechanical degradation of polyetherimide (PEI) due to Friction-based Injection Clinching Joining (F-ICJ) and the effects on the mechanical strength of hybrid joints with aluminum. PEI samples extracted from process-affected regions of the joints were characterized in terms of their molecular weight distribution (MWD) and glass transition temperature (T-g), while mechanical strength of the joints was evaluated by cross tensile testing. PEI samples produced by the most severe joining condition showed decrease of 37% of number-average molecular weight (M-n) and 17% of weight-average molecular weight (M-w), while polydispersity index (M-w/M-n) increased 33% as compared with as-received polymer. The chain scission distribution function (CSDF) indicated non-random multiple scissions as the main degradation mechanism of PEI due to F-ICJ. From the dependence of T-g with M-n the parameters of the Fox-Flory equation for PEI were obtained. A fractional factorial design of experiments was adopted to analyze the influence of the process parameters on the polymer degradation, based on T-g values. High level of PEI degradation and microstructural defects caused by high energy inputs have combined negative effect on the ultimate cross tensile force and displacement of joints. In general, these results can contribute to the knowledge of thermomechanical degradation of PEI and help with the optimization of F-ICJ. (AU)

• FAPESP's process: 13/26293-4 - Friction based injection clinching joining of hybrid joints of polyetherimide and aluminium 6082-T6
• Grantee: Marilia Sonego
• Support Opportunities: Scholarships in Brazil - Master