Synthesis of block copolymers by using polysilanes

Abstract

Poly(methy1 phenyl silane) was used to photoinitiate the polymerization of methyl methacrylate. Poly(methy1 methacrylate) (PMMA), obtained this way, contains remaining polysilane chains. Photolysis of this PMMA in the presence of vinyl monomers such as styrene makes it possible to prepare block copolymers. Such PMMA prepolymers were also used to induce the polymerization of cyclohexene oxide through formation of PMMA-attached silyl radicals and subsequent oxidation to the corresponding ions in the presence of N-ethoxy-2-methylpyridinium hexafluorophosphate resulting in the formation of a block copolymer. ZUSAMMENFASSUNG:Methylmethacrylat wurde mit Poly(methylphenylsi1an) als Photoinitiator polymerisiert. Durch Photolyse der in dem so hergestellten Polymethylmethacrylat (PMMA) noch enthaltenen Polysilanketten in Gegenwart von Vinylmonomeren wie Styrol wurden Blockcopolymere erhalten. Diese wurden eingesetzt, um Blockcopolymere mit Cyclohexenoxid herzustellen. Dies geschieht durch die Bildung von an PMMA gebundenen Silylradikalen, die in Gegenwart von N-Ethoxy-2-methylpyridinium-hexafluorphosphat zu den entsprechenden Kationen oxidiert werden.

Synthesis of organic-inorganic chiral block poly(methylphenylsilane) functional polymers, and study of their optical and chiroptical properties

“…The photolysis of polysilanes produces silyl radicals which were used for radical polymerization of vinyl monomers . Polysilane was also used as a photoinitiator for cationic polymerization of cyclic ethers such as cyclohexene oxide and vinyl ether.…”

Well‐Defined Cyclohexene Oxide Mid‐Chain Functional Polystyrene Macromonomer: Synthesis, Characterization and Photoinitiated Cationic Homo‐ and Copolymerization

“…There are many publications on the use of photoinitiated cationic polymerization for the preparation of block copolymers. [33][34][35][36][37][38] However, the corresponding graft copolymerization via a similar photoinduced process has received little attention. [8,39] It occurred to us that the macromonomer method involving CHO mid-chain functional polymers might be particularly useful because photochemically generated cationic species are quite reactive towards these groups.…”

Polymers with Side Chain N‐Alkoxy Pyridinium Ions as Precursors for Photoinduced Grafting and Modification Processes

“…[4][5][6][7][8][9][10][11] As part of our continuous interest in developing photoinitiating systems for block and graft copolymerization, we have reported a wide range of photoactive groups suitable for such processes. [12][13][14][15][16][17][18] Among them, N-alkoxy pyridinium and N-alkoxy isoquinolinium salts with non-nucleophilic counterions have the unique feature of producing both radical and cationic species and initiating respective polymerizations concurrently [19] or independently. [20,21] In a previous study, we took the advantage of free radical initiation capability of this class of ions for the preparation of block copolymers.…”