Flexible Backbone Aromatic Polyimide Adhesives

Abstract

St. C l a i r . Also prepared and evaluated was an endcapped version o f PIS02. These two polymers were compared with LARC-TPI and LARC-STPI, polyimides researched i n our l a b o r a t o r y and r e p o r t e d i n t h e 1 i t e r a t u r e . ' . The adhesive evaluation, p r i m a r i l y based on l a p shear s t r e n g t h (LSS) t e s t s , i n v o l v e d preparing adhesive tapes, conducting bonding s t u d i e s and exposing l a p shear specimens t o 204°C a i r f o r up t o 1000 h r s and t o a 72-hour water b o i l . LSS t e s t s a t RT, 177°C and 204°C were performed before ( c o n t r o l s ) and a f t e r these exposures. The type o f adhesive f a i l u r e as w e l l as the Tg was determined f o r t h e f r a c t u r e d specimens. The r e s u l t s i n d i c a t e t h a t LARC-TPI provides the h i g h e s t LSSs, 33 MPa a t RT, 30 MPa a t 177"C, and 26 MPa a t 204°C. LARC-F-SO2, LARC-TPI andLARC-STPI a l l r e t a i n t h e i r strengths a f t e r thermal exposure f o r 1000 h r s and PIS02 r e t a i n s g r e a t e r than 80% o f i t s c o n t r o l strengths.Most o f t h e f o u r adhesive systems showed reduced s t r e n g t h s f o r a l l t e s t temperatures a1 though s t i 11 r e t a i n i n g a high percentage o f t h e i r o r i g i n a l s t r e n g t h ( > 60%) except f o r one case.

Structure analysis of a soluble polysiloxane-block-polyimide and kinetic analysis of the solution imidization of the relevant polyamic acid

“…[2][3][4][5][6] Recently, solution imidization with continuous water removal has been reported for the synthesis of soluble polyimides. [7][8][9][10] In this case, the imidization was found to proceed by second-order kinetics, 11 although the fully imidized polyimide has not been prepared thus far.…”

“…[7][8][9][10][12][13][14] In our previous paper their thermal and mechanical properties as well as the morphology and surface properties were described. 15 We showed that the properties of these copolyimides depend mainly on the composition and chain length of the polysiloxane segments.…”

Preparation of Meltable Aromatic Polyimides and Their Adhesive Properties

“…Therefore, thermoplastic PIs, which generally contain flexible structures in their backbone, have been developed as high-temperature structural adhesives (17,18). Thermoplastic PIs are soluble and meltable, which allows them to be processed in imidized form to prepare unsupported (i.e., neat adhesive) or supported adhesive films (13,19).…”

Maleic anhydride based copolymer dispersions for surface modification of polar substrates

“…Many researchers have reported the introduction of PDMS into polymer materials to improve their flexibility and to provide a linkage of PDMS to the textile surface 23–28. Also, several kinds of copolyimides containing PDMS in their polymer backbone (polysiloxane‐ block ‐polyimides) have been reported 29, 30…”