Abstract
High-temperature-resistant polymeric adhesives with high servicing temperatures and high adhesion strengths are highly desired in aerospace, aviation, microelectronic and other high-tech areas. The currently used high-temperature resistant polymeric adhesives, such as polyamic acid (PAA), are usually made from the high contents of solvents in the composition, which might cause adhesion failure due to the undesirable voids caused by the evaporation of the solvents. In the current work, electrospun preimidized polyimide (PI) nano-fibrous membranes (NFMs) were proposed to be used as solvent-free or solvent-less adhesives for stainless steel adhesion. In order to enhance the adhesion reliability of the PI NFMs, thermally crosslinkable phenylethynyl end-cappers were incorporated into the PIs derived from 3,3’,4,4’-oxydiphthalic anhydride (ODPA) and 3,3-bis[4-(4-aminophenoxy)phenyl]phthalide (BAPPT). The derived phenylethynyl-terminated PETI-10K and PETI-20K with the controlled molecular weights of 10,000 g mol−1 and 20,000 g mol−1, respectively, showed good solubility in polar aprotic solvents, such as N-methyl-2-pyrrolidinone (NMP) and N,N-dimethylacetamide (DMAc). The PI NFMs were successfully fabricated by electrospinning with the PETI/DMAc solutions. The ultrafine PETI NFMs showed the average fiber diameters (dav) of 627 nm for PETI-10K 695 nm for PETI-20K, respectively. The PETI NFMs showed good thermal resistance, which is reflected in the glass transition temperatures (Tgs) above 270 °C. The PETI NFMs exhibited excellent thermoplasticity at elevated temperatures. The stainless steel adherends were successfully adhered using the PETI NFMs as the adhesives. The PI NFMs provided good adhesion to the stainless steels with the single lap shear strengths (LSS) higher than 20.0 MPa either at room temperature (25 °C) or at an elevated temperature (200 °C).
Highlights
The phenylethynyl-terminated poly(amic acid)s (PET-polyamic acid (PAA)) were first synthesized from oxydiphthalic anhydride (ODPA), BAPPT and PEPA, which were dehydrated at 180 ◦ C to convert to the final PETI resins
The continuous silky PETI-20K resin and the short rod-like PETI-10K resin were obtained, which indicates that the molecular weights of the resins were different
The derived PETI nano-fibrous membranes (NFMs) were endeavored to be used as the acterized in the current work
Summary
High-temperature-resistant adhesives generally refer to a class of special adhesives that can be used for a long time at hundreds of degrees centigrade or for a short time at temperatures over thousands of degrees centigrade [3] They are usually used for structural bonding in supersonic missiles, launch vehicles, satellites, aircrafts and other components serving in harsh thermal environments, as shown in Figure 1 [4]. Structure, and solvent‐free which are allsurface required for high high-performance It can be characteristics, which are all required for high‐performance adhesives anticipated that if the PI NFMs were used as adhesives, it is possible to[20,21,22,23]. The effects of the designed molecular structure on the thermal and optical properties of PETI NFMs were studied
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
