Reversible addition fragmentation chain transfer polymerization of sterically hindered monomers: Toward well‐defined rod/coil architectures

Abstract

The sterically hindered monomers dibutyl itaconate (DBI) and dicyclohexyl itaconate (DCHI) were polymerized via reversible addition fragmentation chain transfer (RAFT) free‐radical polymerization. S,S′‐Bis(α,α′‐dimethyl‐α″‐acetic acid) trithiocarbonate, cumyl dithiobenzoate, and cumyl phenyldithioacetate have been used as RAFT agents to mediate a series of polymerizations at 65 °C yielding rod polymers ranging in number average molecular weight from 9000 to 92,000 g mol−1. The progress of the polymerization was followed via online Fourier transform–near infrared spectroscopy. The polydispersity indices of the obtained rod polymers were relatively high at 1.4–1.7. The RAFT polymerizations of the hindered monomers used in the present study displayed both ideal living and hybrid behavior between conventional and living polymerization, depending on the RAFT agent used. DCHI rod polymers generated via the RAFT process were subsequently reinitiated in the presence of styrene to produce a range of BAAB and A‐B rod‐coil block copolymers of molecular weights up to 164,000 g mol−1. The chain extension yields molecular weight distributions that progressively shift to higher molecular weights and are unimodal. Thermogravimetric analysis of the pDCHI‐block‐pStyrene copolymers indicates thermal degradation in two separate steps for the pDCHI and pStyrene blocks. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2432–2443, 2004

RAFT Polymerization of N‐Isopropylacrylamide and Acrylic Acid under γ‐Irradiation in Aqueous Media

“…TRITT, a symmetrical trithiocarbonate, has already been used as a CTA for the RAFT polymerization of several monomers, such as acrylates, methacrylates, styrenics, and acrylamides. [32][33][34][35][36] Inspection of the data given in Figure 1A and B clearly indicates that TRITT allows for excellent control of NIPAAm polymerization. With a NIPAAm/TRITT ratio of 800, the first-order time-conversion plot ( Figure 1A) displays a small induction period of close to 20 min.…”

Experimental Requirements for an Efficient Control of Free‐Radical Polymerizations via the Reversible Addition‐Fragmentation Chain Transfer (RAFT) Process

“…Me-MMA [41,67,68] a,b) [9] Sty [9,13,68,69]b) [70,71] BA [9,72] Et-MA [73] PhCH 2 -MMA [41,74] b) [75] NMAS [76] Dendron-MA [77] DBI [78] DCHI [78] Sty [74,[79][80][81][82][83] a) [84,85] b) [75,[86][87][88][89][90][91][92][93] c) [94] StyCH 2 Cl [84,95] MA [73,83,[96][97][98][99] BA [99][100][101] b) [89,90] DA [102] Am …”

“…. [181] EAA a) [182] EEA a) [182] EOHMA [183] SPP a) [184] DBI [78] DCHI [78] MASASP [160] MBAm [249] AN [296,297] a) [72,110] (p-MeO)Ph-MMA [124,127] Sty [127] MA [73] StyOCOMe [240] BA [127] (p-CN)Ph-MMA [124] MA [73] (m-CF 3 )PhStyOCOMe [240] (p-F)Ph-MMA [124] Sty [127] MA [251] BA [127] (p-Ph)Ph-MMA [124] Sty [127] BA [127] …”

“…MMA [356] a) [357] Sty [356,358] AA [358] Oct a) [357] DBI [78] MeSty [358] MA [356] ABE a) [359] DCHI [78] EA [358] BA [123,258,345,358] a) [357,359] EHA [358] HEA [358] Am [103,360] tBAm [358] DMAm [360] …”

CMC and Phase Separation Studies of RAFT Mediated Amphiphilic Diblock Glycopolymers with Methyl Acrylate and Styrene

“…[17,[24][25][26] In comparison to most controlled polymerization techniques, the RAFT process is a robust and versatile method of obtaining polymeric materials of narrow molecular weight distributions. [27] Advantages include it being applicable to a wide range of monomers, increased tolerance to small amounts of impurities, compatibility with various solvents, being amenable to a wide range of working temperatures [28][29][30] and the synthesis of a variety of molecular architectures. [31][32][33] Aqueous RAFT mediated polymerizations of glycomonomers have been successfully carried out, [17,[24][25][26]32,34] using water miscible RAFT agents and hydrophilic monomers, for chain extension studies.…”