Mechanisms for combining polyamide and epoxy and their effects on mechanical performance—A review

Abstract

This paper provides an in-depth study in the various methods for toughening epoxy (EP) resin with polyamide (PA) across a range of length scales—from the atomic to the macroscopic. This allows for a fundamental understanding of the EP-PA system, as many of the atomic interactions and their kinetics inform the macroscopic mechanical properties. The kinetics of the EP-PA reaction prove that covalent bonding is energetically favorable, enabling chemical crosslinking between EP and PA. The two polymers can then mechanically interlock under a number of different processing conditions including forming a homogeneous mixture of the two, incorporating the PA into the EP in the form of fine particles, or adding the PA to an EP-fiber composite. Though each of these methods allows for the tailoring of processing conditions and final structures to an individual use, the literature shows that the underlying physical and chemical interactions can be applied to all EP-PA systems. Thus, lessons learned through the study of one EP-PA structure can be valuable in predicting the behavior of different EP-PA blends and material form combinations.

Nylons with Applications in Energy Generators, 3D Printing and Biomedicine

“…EP and PA can undergo chemical cross-linking to form an EP/PA coating, which is widely utilized due to its exceptional anti-corrosive properties on metal substrates, resistance to abrasion and affordability. Thus, it is expected, and confirmed, that an EP/PA triboelectric layer would yield a sturdy and efficient TENG [ 63 ]. As a result, because of the excellent corrosion resistance and abrasion performance of the EP/PA coating, the W-TENG shows excellent durability in long-term work, where Ag NPs and O 2 are successfully synthesized by this W-TENG-based electrochemical synthesis system.…”

Examining the Quasi-Static Uniaxial Compressive Behaviour of Commercial High-Performance Epoxy Matrices

“…Although the exact nature of the toughening agents used in the materials in the present study are proprietary, common candidates for this purpose include terminally-functionalised (telechelic) engineering thermoplastics which are capable of forming covalent bonds with the matrix [27] as well as participating in a range of non-covalent interactions (e.g., π-π stacking where both the matrix and the toughening agent contain aromatic moieties). Other notable mechanisms to facilitate strong interfaces between the matrix and toughening agent include electrostatic interactions, where strongly polar bridging species are present, or through the formation of hydrogen bonds [28], and dispersion forces such as van der Waals' associations, which become more influential in aliphatic polymer matrices [29]. For example, the use of an epoxy-compatible thermoplastic toughening agent in the epoxy matrix CYCOM ® 977-2 (B) leads to a reduction in the compression modulus and an increase in compression stress values across the entire stress-strain plot, including the compression yield stress value, compared to the baseline matrix CYCOM ® 890 (A).…”