Miscibility of polyimide with polymeric primer and its influence on adhesion of polyimide to the primed copper metal: Effect of precursor origin

Poly(amic acid) (PAA) and poly(amic diethyl ester) (PAE) precursors of poly(4,4'-oxydiphenylene biphenyltetracarboximide) (BPDA-ODA PI) were synthesized. Miscibility behaviors of these precursors with poly(arylene ether benzimidazole) (PAEBI), which is a good adhesion primer for copper metal, were investigated in N-methyl-2-pyrrolidone (NMP) as well as the condensed state and the imidized state. For the PAA/PAEBI blend over the whole range of compositions, no cloud point was measured either in the NMP solution, the condensed state, or the imidized state. Furthermore, no aggregation of PI chains in the blend films was detected by X-ray diffraction. These results indicate that the PAA and PAEBI are completely miscible at the molecular level, consequently leading to the miscible PI/PAEBI blend. This miscibility might result from the strong interaction via the complex formation of imidazole groups of the PAEBI and carboxylic acid groups of the PAA precursor. In contrast, the miscibility of PAE/PAEBI blend in NMP was limited up to a concentration of 13.5-36.3 wt%, leading to a phase separation in the soft-baked and imidized blend. The blend films rich with one component were optically transparent, which might be due to the phase-separated domains much smaller than 1 mu m. The immiscibility might result from the relatively weak. interactions of imidazole groups of PAEBI with both the ester and amide Linkages in the PAE precursor. The difference in the miscibilities of PAEBI with the PAA and PAE precursors was reflected in the adhesion of PI/PAEBI/copper joints: higher miscibility gave higher adhesion strength

Preferential salvation. effect on polymer dimensions†

In this paper we discuss the light scattering theory of preferential solvation. We also present a more recent theory predicting a preferential solvation dependence on polymer molecular weight. These theories have been confirmed by the experimental results of the present work. It was established that the polymer coil dimensions depend on the local solvent composition and not on the analytical one. The local solvent composition can be calculated, in certain cases, from the value of the preferential solvation coefficient. © 1976, Taylor & Francis Group, LLC. All rights reserved

Characteristic numbers of polymers in dilute solution : a universal description of the cross-over effects

The viscosimetric behaviour of eleven polymer-solvent systems is analysed in order to determine the characteristic numbers in the beginning and in the end of the cross-over region. In the beginning we have a cross-over between Gaussian and excluded volume behaviour and in the end a cross-over between partial excluded-volume and complete excluded-volume behaviour (in the second cross-over the chain exhibits an excluded volume statistics on a macroscopic scale and starts the linearity between log [η ] and log M). We show that in the beginning and in the end of the cross-over region the characteristic molecular weight or the characteristic number of monomers is different for different polymers and the second is related to the stiffness of the chain. In the contrary, the characteristic number of statistical segments in the beginning and in the end of the cross-over region are about the same for all the polymers, and this result confirms the validity of a universal description of polymer solutions.Le comportement viscosimétrique de onze systèmes polymère-solvant a été analysé afin de déterminer les nombres caractéristiques au début et à la fin d'une zone de raccordement. Au début de cette zone les polymères passent d'un comportement gaussien à un comportement de volume exclu (masse moléculaire Mc) et à la fin de cette même zone les polymères passent d'un comportement partiellement obéissant au volume exclu à un comportement obéissant pleinement au volume exclu (masse moléculaire M'c). A ce deuxième point on peut dire que nous avons une statistique de volume exclu à longue échelle et nous avons le début de la linéarité entre log [η] et log M. Nous avons montré qu'au début et à la fin de la zone de raccordement le poids moléculaire ou le nombre des motifs monomères sont différents pour les différents polymères et il existe une relation linéaire entre les motifs monomères et la rigidité de la chaîne pour le deuxième point de raccordement. Par contre, le nombre des segments statistiques au début et à la fin de la zone de raccordement est presque le même pour tous les polymères et cela confirme la validité d'une description universelle de solutions des polymères

Étude morphologique de copolymères statistiques chlorure de vinyle-diphénylpropène en milieu solvant binaire tétrahydrofuranne benzène

Nous présentons ici les résultats d’une étude effectuée sur les copolymères statistiques chlorure de vinyle-diphénylpropène en solution dans un mélange de deux liquides. Nous avons montré l’existence de phénomènes de solvatation préférentielle et mis en évidence la protection exercée sur les autres motifs par ces motifs solvatés

The Relationship between the Unperturbed Dimensions of Polymers in Mixed Solvents and the Thermodynamic Properties of the Solvent Mixture

The unperturbed dimensions of polystyrene and poly(2-vinylpyridine) have been measured in solvent-precipitant mixtures of various compositions using the Stockmayer–Fixman representation. It is possible to obtain a linear relationship between Kθ and ΔGE (the excess free enthalpy of mixing of the solvents) if, instead of using the bulk composition of the mixture, one introduces its “local” composition. This composition is calculated from the values of the preferential adsorption coefficient measured by light scattering. © 1973, American Chemical Society. All rights reserved