Thermal and mechanical properties of the precursor polymers: Comparison of their properties with poly(amic acid)

1999 ◽  
Vol 39 (4) ◽  
pp. 638-645 ◽  
Author(s):  
Jin-Hae Chang ◽  
Richard J. Farris
1989 ◽  
Vol 153 ◽  
Author(s):  
T. H. Yoon ◽  
C. A. Arnold ◽  
J. E. McGrath

Polyimides are attractive candidates for advanced electronic and space applications due to their high performance thermal and mechanical properties. However, the typical intractability and insolubility of polyimides has been a disadvantage. Utilization of the soluble intermediate amic acid can, to some extent, circumvent this problem. However, drawbacks to this approach include the hydrolytic instability of the amic acid and the liberation of water during its subsequent thermal cyclization. Residual stress build-up at the imide-substrate interface may occur due to swelling and drying cycles caused by the loss of water and solvent. In addition, the liberation of volatiles from a polyimide adhesive or coating can lead to the creation of voids which may significantly detract from mechanical properties. Polymeric adhesives must flow in order to provide good wetting of adherend surfaces and consolidation of the bond components. Thus, fully imidized, melt and solution processable, high Tg aromatic polyimides are of great interest.


2006 ◽  
Vol 111 ◽  
pp. 43-46
Author(s):  
B.K. Chen ◽  
S.Y. Tsay ◽  
C.P. Chen

To improve the thermal and mechanical properties of polyimides, a nanocomposite of naphthalene containing polyimide (PI) was hybridized with Montmorillonite (MMT). The PI was synthesized from a diamine, 2,7-bis (4-aminophenoxy) naphthalene and polymerized with a 3,3’,4,4’-benzophenone tetracarboxylic dianhydride via thermal imidization. PI-MMT nanocomposites were then prepared from a DMAc solution of poly(amic acid) precursor and a DMAc dispersion of MMT which were organo-modified with various amount of n-dodecylamine. Characterization results demonstrated that the introduction of a small amount of MMT (up to 5%) led to enhanced thermal stability and mechanical properties of PI. The 5% weight loss temperature in N2 was increased by 46oC in comparison to pristine PI with an organoclay content of 5%. The CTE and dielectric constant were decreased. However, at organoclay contents higher than 5% these properties were reduced because the organoclay was poorly dispersed and resulted in aggregate formation.


2021 ◽  
Vol 12 (16) ◽  
pp. 2379-2388
Author(s):  
Jules Stouten ◽  
Aleksandra A. Wróblewska ◽  
Glenn Grit ◽  
Jurrie Noordijk ◽  
Bert Gebben ◽  
...  

A new biobased alternative for terephthalic acid (TPA) in (semi-)aromatic polyamides is proposed, namely 4-carboxybenzene propionic acid (4CBPA).


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