Structures and rheological properties of reactive solutions of block copolymers. Part I. Diblock copolymers in a liquid epoxy monomer |
| |
Authors: | Thomas Fine Frédéric Lortie Jean-Pierre Pascault |
| |
Affiliation: | a Laboratoire des Matériaux Macromoléculaires, UMR CNRS 5627/Ingénierie des Matériaux Polymères, INSA de Lyon, 20 Avenue A. Einstein, 69 621 Villeurbanne Cedex, France b Laboratoire des Matériaux Polymères et Biomatériaux, UMR CNRS 5627/Ingénierie des Matériaux Polymères, ISTIL, Université C. Bernard Lyon 1, 15, Boulevard Lartajet, 69 622 Villeurbanne Cedex, France |
| |
Abstract: | P(S-b-MMA) and P(B-b-MMA) diblock copolymers (BCP) have been solubilized in a liquid epoxy. The obtained solutions have been characterized by rheology and small angle X-ray scattering (SAXS). As in the solid state, BCP can self-organize in solution to form well-ordered micellar structures. The two blocks respective roles have been clearly identified: at room temperature the PS or the PB block microsegregates while the PMMA block for which epoxy constitutes a good solvent, acts as a stabilizer of the microphase separation. The geometries and thermal stabilities of the ordered structures depend strongly on the molar masses and the chemical nature of the BCP blocks. For instance, the total molar mass of the BCP has to be high enough to obtain a periodic structure. On the contrary, if this molar mass is too high, too long relaxation times prevent the system from reaching its equilibrium. For the P(S-b-MMA) copolymer solution, a transition temperature from an order to a disorder state (TODT) is observed. The origin of this transition has been attributed to a solubilization of the PS domains around TODT. Macroscopically, this transition can be defined as a solid-like to a liquid-like transition. In the case of the P(B-b-MMA) copolymer solution, no order-disorder transition has been observed: it can be explained by the fact that the PB blocks are not soluble in epoxy at any temperature, up to T=200 °C. |
| |
Keywords: | Block copolymers Reactive solvent SAXS |
本文献已被 ScienceDirect 等数据库收录! |
|