Problem with imidization studies

In most of the studies discussed above, except for the meta-linked diamines, when the aromatic content (dianhydride and diamine chain extender), of the copolymers were increased above a certain level, the materials became insoluble and infusible 153, i79, lsi) solution to this problem with minimum sacrifice in the thermal properties of the products has been the synthesis of siloxane-amide-imides183). In this approach pyromellitic acid chloride has been utilized instead of PMDA or BTDA and the copolymers were synthesized in two steps. The first step, which involved the formation of (siloxane-amide-amic acid) intermediate was conducted at low temperatures (0-25 °C) in THF/DMAC solution. After purification of this intermediate thin films were cast on stainless steel or glass plates and imidization was obtained in high temperature ovens between 100 and 300 °C following a similar procedure that was discussed for siloxane-imide copolymers. Copolymers obtained showed good solubility in various polar solvents. DSC studies indicated the formation of two-phase morphologies. Thermogravimetric analysis showed that the thermal stability of these siloxane-amide-imide systems were comparable to those of siloxane-imide copolymers 183>. 

It is frequently asserted that two weaknesses of STM are first that all atomic asperities in images need not necessarily correspond to atom surface positions and second that it is inherently difficult to establish the identity of imaged atoms when two or more surface species are involved. The latter need not, however, be a problem. In a study (for example) of the oxidation of ammonia at Cu(110) the oxygen and nitrogen adatoms form separate individual structures which run in the < 100 > and < 110 > directions, respectively, whereas under ammonia-rich conditions only imide species are formed, running in the < 110 > direction, with in situ XPS confirming their presence and the absence of surface oxygen (Chapter 5). 

However, the fact is that in comparison to ABS with AMS-based matrix only, ABS with imide-based matrix has superior heat resistance properties but has relatively poor fluidity and mechanical properties and therefore can only be used in a limited fashion. To overcome such problems, research in compatibility and thermodynamic studies of the ternary blend comprised of grafted ABS, SAN, and imide-based matrix is ongoing. 

To resolve the problems associated with safety, thermal and electrochemical stability and conductivity, new syntheses of new electrolytes are the subject of new and important studies. Not withstanding the importance of the methide salt for which commercial availabhity is expected shortly, a number of important new developments are worth highhghting. Lithium bis(perfluoro-ethyl-sulfonyl)imide, liNCSOzCzFjjz or IJBETI, is very similar to that for the imide salt as it is stable up to 330°C [26]. hi addition to its high thermal stabhity, the LiBElT salt was also shown to be unreactive towards water [27]. The studies by Barthel et al. on chelatoborates [32] such as bis[2,3-pyridinediolato(2-)-0,0"]borate are of special interest as are studies on new methide salts such as Li[C2(S02CF3)4(S204C3F6)] [32]. 

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