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Amorphous Cross-linked Polyimides Type II

Generally, the aim of the study on crosslink polyimides is an attempt to enhance their gas selectivity and physical stability for gas-induced swelling and plasticization. Several [Pg.7]

The etherification reaction of polyimides is similar to the process of the imide ringopening reaction. It was demonstrated for the reaction of polyimides with primary diamine and epoxy agents [57,58] (for example, for 6FDA-TeMPD polyimides and tet-raglycidyldiaminodiphenylmethane (TGDDM), diethyltoluenedianune (DETDA) [57], TMPDA, 1,3-phenylenediamine (PDA) and4,4 -(9-fluorenylidene)dianiline (FDA) [58]). The density of polymers and crosslink concentration inaeased with the increase in epoxy content. [Pg.8]

It is known that the crossUnk reaction proceeds with participation of photo reactive benzophenone and alkyl chains under UV irradiation [59,60]. Many benzophenone-containing BTDA-based polyimides have been synthesized and their cross-linking investigated [61-69]. The same effects as discussed earlier were observed due to increases in the UV irradiation time. [Pg.8]

Hyperbranched polyimides can result due to the self-polycondensation reactions of AB2-, A2- and Bs-types. The preparation of hyperbranched polyimides involves chemical imidization of polyamic acid ester synthesized from AB2-monomers, which are carboxylic dianhydrides containing an ether bond and a diamine [6,19,76]. Polyamic acid in combination with a condensation agent is used because it is difficult to separate the synthesized polymer from AB2-type monomers. [Pg.9]

Other examples of self-polycondensation of an AB2-type monomer containing an imide-ring via etherification reactions can be found in the literature [7,10,77]. The selfpolycondensation can be performed though nucleophilic etherification of silylated phenol and aryl fluoride in diphenylsulfone at 240 °C under the presence of caesium fluoride [Pg.9]


See other pages where Amorphous Cross-linked Polyimides Type II is mentioned: [Pg.7]    [Pg.13]   


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