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Polyimides as Adhesives: -Literature review

Much like the subject of polymer crystallization, the field of adhesion is vast and thus it is impossible to even remotely cover the area in a review of this size. The material presented therefore is intended to cover a few selected topics that are more relevant to the author's research. The selection of topics is therefore guided by the author's choice. To quote R.C. Patrick 1 , " adhesion is the phenomenon of causing two materials to be held together, while an adhesive is the material utilized in carrying out this phenomenon ". This simple definition avoids much debate and confusion that has surrounded the exact meaning of the word adhesion. This fascinating field, however, has come a long way since man first realized that the blood caused his hair to cling together quite glutinously. Specifically, major strides have been made in the second half of this century, and these have enabled a more fundamental understanding of the subject. Notably, major interest has risen in the past decade or so regarding the use of various adhesives for military, aerospace and microelectronic and applications 2. In this regard, aromatic polyimides and related polymers have been of significant importance. Specifically, these materials possess a broad array of superior properties like excellent thermal stability, solvent resistance, good mechanical properties, radiation resistance, low thermal expansion, wear resistance, hydrolytic stability, low dielectric constant and high breakdown voltage 3. This broad range of attractive properties in these high performance polymers has made them excellent candidates as adhesives.