Telomerization of acrylic acid with mercaptans: Part 2. Kinetics of the synthesis of star‐shaped macromolecules of acrylic acid

Abstract

The telomerization of acrylic acid with a polyfunctional transfer agent initiated by 2,2'azobisisobutyronitrile, was ®rst investigated in an organic medium (THF) at 65°C. Transfer constants (C T ) for three mercaptans, ethylene glycol bisthioglycolate, trimethylolpropane tris(2-mercaptoacetate) and pentaerythritol tetrakis(3-mercaptopropionate) of about 6.1, 6.3 and 7.3, respectively, were determined. From these results, it followed that a well-de®ned star poly(acrylic acid) could not be synthesized via telomerization of acrylic acid in THF. Nevertheless, the same study was performed with the tetrafunctional transfer agent in water/THF mixtures. This work emphasized that the nature of the solvent plays an important role in determining the transfer constant. Thus, the value of C T for the tetrafunctional transfer agent decreased from 7.3 in THF to 1, the`ideal' case for telomerization (C T % 1), for the mixture of solvents water/THF (80%, 20%, v/v). With this route, it seems that acrylic acid star-shaped macromolecules could be synthesized via telomerization.

Star-shaped poly(oligoethylene glycol) copolymer-based gels: Thermo-responsive behaviour and bioapplicability for risedronate intranasal delivery

“…The remaining sample was precipitated in hexane then filtered and the filtrate was evaporated under vacuum. The residue left after evaporation was dissolved in water then any PETMP left was determined by iodine titration to determine telogen conversion (Loubat and Boutevin, 2001).…”

“…Yuan et al studied the telomerization of methyl methacrylate with the tetrafunctional transfer agent PETTMP and found a CT to be 0.64 (Yuan and Di Silvestro, 1995). It is assumed that the smaller the value of transfer constant (CT ≈1) is an indication of telomerization reaction efficiency (Loubat and Boutevin, 2001;Pardal et al, 2009).…”

Influence of Acrylic Acid on Kinetics of UV-Induced Cotelomerization Process and Properties of Obtained Pressure-Sensitive Adhesives

“…Interestingly, there are only three publications about photoinduced telomerization (photoinitiated reaction between styrene and bromotrichloromethane [ 24 ], telomerization of acrylamide in water in the presence of disulfide telogen [ 25 ] and telomerization of tetrafluoroethylene initiated by benzoyl peroxide (as photoinitiator and telogen)) [ 26 ]. In the literature, relative numerous papers describe the telomerization process of acrylic acid [ 27 , 28 , 29 , 30 , 31 , 32 ]. In contrast, cotelomerization of acrylic monomers is rarely investigated (cotelomerization of acrylic acid and n -octyl acrylate, 2-ethylhexyl acrylate or 2-phenylethyl acrylate in presence of 2-aminoethanethiol hydrochloride [ 33 ] and cotelomerization of methyl methacrylate and maleic anhydride with dodecyl mercaptan [ 34 ]).…”

Synthesis of amphiphilic heteroarm star‐shaped polymer via free radical polymerization using polyfunctional chain transfer agent and its self‐assembly behavior

“…Yuan et al40,41 also investigated theoretically and experimentally free radical polymerization of MMA in the presence of PETMP, in which star polymers formed exclusively in the absence of combination termination. Loubat and Boutevin42 investigated the transfer constants of acrylic acid (AA) for PETMP in different solvents and discovered ideal telomerization ( C T = 1) of AA in water/THF (70/20, v/v) solvent. On the basis of the above research, our group synthesized heteroarm star‐shaped PMMA/PS copolymer using conventional free radical polymerization in the presence of P‐CTA 43 .…”