Preparation and characterization of telechelic poly(methyl methacrylate). 2. Anionic polymerization with a difunctional initiator derived from 4-[2-(tert-butyldimethylsiloxy)ethyl]-.alpha.-methylstyrene

Abstract

Novel telechelic poly (methyl methacrylate) having OH and COOH groups in the chain was prepared by anionic polymerization with the difunctional initiator made by the reaction betweem 4-[2-(tert-butyldimethylsiloxy)ethyl]-«-methylstyrene and sodium napththalene, followed by termination with carbon dioxide and hydrolysis of the tert-butyldimethylsiloxy group. The resulting polymer was characterized by osmometry, GPC, NMR, and potentiometric titration. OH groups were introduced quantitatively, but the number of the terminal COOH groups per molecule was 1.7 S0.1 which is less than the theoretical value, 2. The latter result was because part of the initiator was doubly charged and the rest had one charge plus a nonactive end, and/or the initiation efficiency in the reaction between the initiator and methyl methacrylate was low. The characterization assures that the multifunctionality of the polymer necessary for self-crosslinking is presented.samples were precipitated from THF solution into excesses of n-hexane and methanol, respectively. The precipitated samples were further purified by reprecipitation in benzene/n-hexane or benzene/methanol systems. The purified polymers were freezedried from the benzene solutions for 24 h.

Preparation and characterization of cyclic polystyrene with short poly(2‐tert‐butylbutadiene) sequences

“…The concentration of the initiator was determined by titration with a standard HCl solution. THF, n ‐heptane, styrene, and 1,1‐diphenylethylene (DPE) were purified with the same methods reported previously 14–16. 2‐ tert ‐Butylbutadiene was synthesized by the reaction of vinyl bromide as a Grignard reagent and pinacolone; this was followed by hydrolysis and dehydration with a 22% yield.…”

Living Anionic Polymerization of 4‐(1‐Adamantyl)‐α‐Methylstyrene

“…The anionic polymerization system of α‐methylstyrenes usually shows equilibrium behaviors known as the thermodynamically reversible polymerization due to the steric strain caused by the α‐methyl group . The polymerization of AdαMS was first carried out with K‐Naph in THF at −78 °C for 8 h in order to achieve the complete consumption of monomer similar to the previous experiment (run 5).…”

“…In this study, we newly designed and anionically polymerized an adamantyl‐substituted α‐methylstyrene derivative, 4‐(1‐adamantyl)‐α‐methylstyrene ( AdαMS ), in order to check the polymerizability of the monomer and the thermal properties of the resulting polymer. It is well known that α‐methylstyrene derivatives usually undergo the equilibrium polymerization under the anionic conditions due to the low ceiling temperatures . The polymerization and depolymerization of α‐methylstyrene derivatives reversibly occur under the equilibrium conditions.…”

“…The anionic polymerization system of α-methylstyrenes usually shows equilibrium behaviors known as the thermodynamically reversible polymerization due to the steric strain caused by the α-methyl group. [43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58] The polymerization of AdαMS was first carried out with K-Naph in THF at −78 °C for 8 h in order to achieve the complete consumption of monomer similar to the previous experiment (run 5). Then, the polymerization temperature of the system was raised to room temperature and the system was stood for 20 h. The characteristic red color of the polymerization system was maintained at room temperature until the termination with methanol.…”

“…It is well known that α-methylstyrene derivatives usually undergo the equilibrium polymerization under the anionic conditions due to the low ceiling temperatures. [43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58] The polymerization and depolymerization of α-methylstyrene derivatives reversibly occur under the equilibrium conditions. In addition, the poly(α-methylstyrene)s generally show higher T g values than those of the corresponding polystyrene derivatives and the ease of the chain degradation on heating.…”