Maleimide terminated polyimides

Diels-AIder Copolymers. The Diels-Alder reaction can also be employed to obtain thermosetting polyimides. If bismaleimide (the bisdienophile) and the bisdiene react nonstoichiometricaHy, with bismaleimide in excess, a prepolymer carrying maleimide terminations is formed as an intermediate, which can then be cross-linked to yield a temperature-resistant network. 

St. Clair et. al. investigated a series of maleimide and nadimide terminated polyimides and developed LARC-13 [8,9]. Changing the terminal group from maleimide to nadimide, the value of the lap shear strength of a titanium lap shear joint increased from 7 to 19 MPa [9]. They also added an elastomeric component to the adhesive formulation. The introduction of 15 wt% of a rubbery component, ATBN (amine terminated butadiene nitrile polymer) and ADMS (aniline terminated polydimethyl siloxane) enhanced the adhesive properties as follows 19 MPa to 25 MPa (ATBN) titanium T-peel strength 0.2 kN/m to 1.4... 

JP 05125345 (Japanese) 1993 Poly(vinyl butyral) blend adhesive composition for flexible printed circuit boards Ube Industries, Japan H Inoe, S Takabayashi, T Muramatsu, T Funakoshi Formulated resins having good flexibility and heat resistance are useful adhesives for polyimide/Cu foil laminated circuit boards Maleimide-terminated siloxane-imide block copolymers were formulated with poly(vinyl butyral) and melamine resins to give adhesive compositions. 

JP 05306386 (Japanese) 1993 Heat-resistant adhesive composition Ube Industries, Japan H Inoe, S Takabayashi, T Muramatsu, T Hirano Resin formulation useful for bonding Cu foils to polyimide films for electronic applications Heat-resistant adhesives were formulated to include imide-siloxanes with softening points <300° C. Diaminopolysiloxanes and aromatic amines were used maleimide termination also utilized. 

Lyle G, Hedrick JC, Lewis DA, Senger JS, Chen DH, Wu SD, McGrath JE (1989) Synthesis and characterization of maleimide terminated poly(arylene ether sulfone)s. In Feger C, Khojasteh MM, McGrath JE (eds) Polyimides materials, chemistry and characterization. Elsevier, Amsterdam, p 213... 

The double bond of maleimides in very reactive towards electron-rich dienes, to give a normal Diels-Alder cycloaddition. Thus BMIs were used to obtain linear polyimides by reaction with several kind of dienes [46-51]. However the dienes are often difficult to prepare [51] and functionalized dienes have been used. Furan terminated oligomers react with BMIs at 70 °C leading to an oxygen-containing cycloadduct [52-57] which can react with acetic anhydride to give an aromatic imide (Fig. 13) [58-59]. 

Bis(maleimides) (BMI) are an important class of polyimides that are characterized by excellent thermal, electrical and mechanical properties Bis(maleimides) are low molecular weight oligomers, generally containing terminal reactive groups. A general structure of a bis(maleimide) is shown in Scheme 28. 

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