Advanced synthesis to obtain a homogeneous blend

In situ and precursor techniques for polymer synthesis are suitable procedures for a combination with a variation of the chemical structure to enhance miscibility. It is the principal 

By thermally induced isomerization of an isoimide to an imide, a series of molecular composites with polyarylsulfone, polysulfone and an acetylene terminated isoimide thermosetting resin were obtained [37]. After two flexible polymeric compounds were blended in solution, films were cast and the isomerization process was carried out. The thermally treated films were insoluble and showed no sign of phase separation. 

Low-temperature solution polycondensations of a series of soluble aromatic polyamides, subjected to thermal cyclization to convert them to the corresponding polybenzothiazoles, were reported starting with 2,5-bis [(methoxycajbonyl)ethyl]thio -l,4-phenylenediamine with aromatic diacid chlorides [38-40]. The introduction of bulky and polar pendant groups in the polyamides improved the solubility of the precursor in organic solvents. 

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