Microphase Separation in Thermosetting Blends of Epoxy Resin and Poly(-caprolactone)-block-Polystyrene Block Copolymers

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• 作者：Fanliang Meng ; Zhiguang Xu ; Sixun Zheng
• 刊名：Macromolecules
• 出版年：2008
• 出版时间：February 26, 2008
• 年：2008
• 卷：41
• 期：4
• 页码：1411 - 1420
• 全文大小：1239K
• 年卷期：v.41,no.4(February 26, 2008)
• ISSN：1520-5835

文摘

The block copolymers, poly(-caprolactone)-block-polystyrene (PCL-b-PS) with the linear and star-shaped topological structures were synthesized via the combination of ring-opening polymerization (ROP) andatom transfer radical polymerization (ATRP). The two block copolymers with the identical block compositionswere incorporated into epoxy to access the nanostructured thermosets. The microphase-separated morphologiesin the systems were investigated by means of atomic force microscopy (AFM) and small-angle X-ray scattering(SAXS). It is identified that the epoxy thermosets can display the long-ranged ordered nanostructures dependingon the concentration of the diblock copolymers. By considering the miscibility of the subchains of the blockcopolymers with epoxy after and before the curing reaction, it is judged that the formation of the nanostructuresfollowed the mechanism of reaction-induced microphase separation. It is noted that the nanoscaled morphologiesof the thermosets are quite dependent on the macromolecular topologies of the block copolymers. For the epoxythermosets containing the linear PCL-b-PS diblock copolymer, the spherical PS nanophases were arranged intocubic (e.g., bcc, fcc, or simple cubic) lattice whereas the PS nanophases into lamellar lattice while the thermosetscontain the tetra-armed PCL-b-PS block copolymer. The difference in nanostructures for the epoxy thermosetshas been interpreted on the basis of the restriction of topological structures of the block copolymers on the formationof nanophases.