Mechanically and Thermally Robust Ordered Nanoporous Monoliths Using Norbornene-Functional Block Polymers

Abstract

A norbornene-functional styrene was synthesized and copolymerized with styrene, and monomer reactivity ratios were calculated in a controlled radical copolymerization. Polylactide-b-poly (norbornenylethylstyrene-s-styrene) (PLA-b-P(N-S)) block polymers were produced by a reversible addition-fragmentation chain transfer polymerization technique using a PLA-based macro chain transfer agent and fully characterized using conventional techniques. Blends composed of this block copolymer, dicyclopentadiene (DCPD), and a metathesis catalyst were waxy materials that formed ordered structures containing cylindrical PLA nanodomains in a composite DCPD/P(N-S) matrix. These composite materials were pressed in a channel die to align the cylindrical domains and were cured by a ring-opening metathesis mechanism at elevated temperatures. Removal of the PLA from the resulting monoliths by mild basic etching resulted in nanoporous monoliths with cylindrical channels. The nanoporous materials were characterized by small-angle X-ray scattering, scanning electron microscopy, and N 2 adsorption experiments. The nanoporous monoliths were thermally stable up to about 130 °C and exhibited remarkable mechanical strength that was comparable to pure polyDCPD.

Living Radical Polymerization by the RAFT Process – A Third Update

“…[440] RAFT polymerization with xanthate (229) was controlled although dispersities were broad. [113,506] This was attributed to the low transfer 373 [469] 378 [347] 379 [347] 386 [413] 387 [289] 391 [465] 392 [434] 393 [451] 388 [538] 389 [583] 390 [395] 380 [433] 383 [470] 384 [470,471] 385 [433] 374 [469] 375 [469] 381 [287] 382 [287] 376 [347,433] 377 [412] Fig. 9.…”

“…from RAFT-synthesized PLA-b-poly(St/386) crosslinked by metathesis polymerization. [413] Nanopores were formed by etching of PLA phase.…”

Nitroxide mediated polymerization of sustainably sourced isobornyl methacrylate and tridecyl methacrylate with acrylonitrile co‐monomer

“…Due to the versatility and simplicity of RDRP, many commercial applications have been targeted. Examples include next‐generation biomaterials, organic electronics, and specialized coatings …”

“…Examples include next-generation biomaterials, 22-24 organic electronics, 25 and specialized coatings. [26][27][28][29][30] NMP is an attractive technique, needing only heat and the nitroxide to initiate polymerization, and does not require Additional supporting information may be found in the online version of this article.…”

Living Radical Polymerization of Bicyclic Dienes: Synthesis of Thermally Cross-Linkable Block Copolymers

“…[6][7][8][9][10][11][12] Cross-linked cylindrical microstructures obtained from block copolymers in thin films and melt provide an access to versatile, solvent-and temperature-resistant nanoporous templates. 13,14 Phase-separated block copolymer microstructures can also be used to fabricate nanofibers and nanotubes by cross-linking the minority component. [15][16][17] Intramolecular cross-linking of low-polydispersity polymers and block copolymers in dilute solutions has been used to prepare well-defined organic nanoparticles.…”