Synthesis and Characterization of a Novel High-Temperature Structural Adhesive Based on MDA-BAPP-BTDA Co-Polyimide

Abstract

A series of polyimide(PI) adhesives were synthesized from 2,2'-Bis [4-(4-aminophenoxy)phenyl] propane(BAPP), 4,4'-Diaminodiphenylmethane (MDA) and 3,3',4,4'-Benzophenonetetracarboxylic acid dianhydride (BTDA) via a two-step process. PI adhesives with different BAPP content were characterized in regard to their structure, thermal stability, mechanical properties and adhesive performance. Results showed that these PIs had excellent thermal stability, whose glass transition temperature (Tg) were around 300 C. While, superior dynamic mechanical behavior was observed, and the maximum loss factor declined with the increase of BAPP content. Single-lap shear strength of over 15.58 MPa at room temperature was obtained, and it remained high even at the temperature of 350 C. Factors that could affect bonding strength of these PI adhesives such as molar ratio of the diamine monomers, surface roughness of adherends and curing processes were investigated.

Synthesis and characterization of novel high temperature structural adhesives based on nadic end capped MDA-BTDA-ODA copolyimide

“…The results of single lap shear stress tests of the PI resins are shown in figure 6. The maximum shear strength was achieved by equimolar mixture of MDA:ODA molar ratio that can be explained by reaching optimum mechanical strength and wetting capability of the copolymer, and this result is in consistent with the literature [34]. The increase in ODA content in the PI copolymers leads to the increase in fluidity that causes the enhancement of polymer-adherent interaction.…”

“…Therefore, the effect of wettability and mechanical strength on the adhesive performance was balanced at 50:50 (MDA:ODA) molar ratio. The adhesion strength values of the copolyimides are nearly in the same range with MDA-BAPP-BTDA co-polyimide synthesized by Li et al [34].…”

“…When a second dianhydride or diamine is introduced into the reaction, the symmetry and repetition of molecular structure is destroyed. Ultimately, the interaction between the rigid chains and crystallinity of the copolymer is reduced [34]. In literature, PMR-15 and LARC RP-46 polyimide homopolymers have been worked; however the effect of both MDA and 3,4′-ODA co-monomers on the processability of the copolyimide consisting these co-monomers has not been studied in detail [35].…”

Curing behaviors and properties of epoxy and self-catalyzed phthalonitrile with improved processability

“…The improvement can be assigned to two factors: on the one hand, the improved adhesive properties of BA-Ph/EP polymers were attributed to the outstanding adhesive properties of EP itself; on the other hand, the copolymerization between BA-Ph and EP, which have significantly improved the cross-linking density, may also be contributed to the good adhesive properties. 31 As discussed above, the BA-Ph/EP polymers with equal percentage of BA-Ph and EP showed the highest cross-linking density and resulted in the best shear strength. Hence, the introduction of EP not only affected the processability of BA-Ph/EP prepolymers but also the final properties of polymers.…”

In situ synthesis of polyimide-based solid lubricating films on the surface of aluminium alloy with improved tribological performance

“…Recently, polyimide (PI) has been extensively concerned due to its outstanding advantages such as excellent thermal stability, mechanical properties, good radiation, and solvent resistance. What is more, PI has excellent antifriction and anti-wear properties even though it is under the environment of high temperature, high pressure, and high speed [6,[20][21][22]. So it is a kind of excellent base material, which is suitable for extreme and special working condition in friction field.…”