Probing the Nanoscale Heterogeneous Mixing in a High-Performance Polymer Blend

Abstract

The blend of polyetheretherketone (PEEK) and polybenzimidazole (PBI) produces a high-performance blend (PPB) that is a potential replacement material in several industries due to its high temperature stability and desirable tribological properties. Understanding the nanoscale structure and interface of the two domains of the blend is critical for elucidating the origin of these desirable properties. Whilst achieving the physical characterisation of the domain structures is relatively uncomplicated, the elucidation of structures at the interface presents a significant experimental challenge. In this work, we combine atomic force microscopy (AFM) with an IR laser (AFM-IR) and thermal cantilever probes (nanoTA) to gain insights into the chemical heterogeneity and extent of mixing within the blend structure for the first time. The AFM-IR and nanoTA measurements show that domains in the blend are compositionally different from those of the pure PEEK and PBI polymers, with significant variations observed in a transition region several microns wide in proximity to domain boundary. This strongly points to physical mixing of the two components on a molecular scale at the interface. The versatility intrinsic to the combined methodology employed in this work provides nano- and microscale chemical information that can be used to understand the link between properties of different length scales across a wide range of materials.

Copolymers of poly(aryl ether ketone)/poly(ether ether amide) containing different numbers of methylene in the main chain: Synthesis and properties

“…1 PEEK can be mixed with other materials to enhance its properties. [2][3][4] However, PEEK has high melting point of 330-340 C, and it is insoluble in most organic solvents at room temperature. 5 Therefore, it can only be processed by melting method, which leads to the need for special processing equipment and also increases the cost of processing.…”

“…Poly(ether ether ketone) (PEEK), as one of the most famous products of PAEs, has high temperature resistance, corrosion resistance, wear resistance, radiation resistance and other properties 1 . PEEK can be mixed with other materials to enhance its properties 2–4 . However, PEEK has high melting point of 330–340°C, and it is insoluble in most organic solvents at room temperature 5 .…”

Impact of Chain Conformation on Structural Heterogeneity in Polymer Network

“…The polymer network structure in systems such as thin films, melts, and solutions is an important factor that influences their physical and mechanical properties, including their viscoelasticity, permeability, tensile strength, mass transport, and plasticization and may be engineered by modulating the conformation of the constituent chains. − The chain conformation of polymers is often governed by the thermodynamic features of the solvent used for processing them. ,− According to the Flory–Huggins theory, − when the polymer–solvent interaction parameter χ is <0, polymer–solvent interactions are energetically favorable, and the polymer chain principally adopts an extended random-coil conformation. If the degree of polymerization exceeds the entanglement molecular weight, the chains entangle with each other above the critical concentration, yielding the commonly known interchain entangled network (Figure ).…”