Copolymerization of n‐butylacrylate with styrene by a novel photoinitiator, 1‐(bromoacetyl)pyrene

Abstract

A comparative study on photoinitiated solution copolymerization of n‐butylacrylate (BA) with styrene (Sty) using pyrene (Py), 1‐acetylpyrene (AP), and 1‐(bromoacetyl)pyrene (BP) as initiators showed that the introduction of a chromophoric moiety, bromoacetyl (COCH2Br), significantly increased the photoinitiating ability of pyrene. The kinetics and mechanism of copolymerization of BA with Sty using BP as photoinitiator have been studied in detail. The system follows nonideal kinetics (Rp ∝ [BP]0.34 [BA]1.07 [Sty]0.97). The nonideality was attributed to both primary radical termination and degradative initiator transfer. The monomer reactivity ratios of Sty and BA have been estimated by the Finemann–Ross and Kelen–Tudos methods, by analyzing copolymer compositions determined by 1H NMR spectra. The values of r1 (Sty) and r2 (BA) were found to be 0.78 and 0.25, respectively, which suggested the high concentration of alternating sequences in the random copolymers obtained. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3233–3239, 2006

Photocatalytic and Thermal Degradation of Poly(methyl methacrylate), Poly(butyl acrylate), and Their Copolymers

“…Figure shows the Fineman−Ross plot for calculating the monomer reactivity ratios, which are r 1 (MMA) = 2.98 and r 2 (BA) = 0.31. These are comparable to the values reported in the literature: r 1 (MMA) = 2.17 and r 2 (BA) = 0.44. The product of reactivity ratios is approximately equal to one, indicating the prepared copolymers are random copolymers.…”

“…The MMA monomer shows a singlet peak corresponding to methoxy of the ester linkage (−OCH 3 ) at δ 3.8. The BA shows a triplet peak corresponding to the ethyleneoxy of the ester linkage (−OCH 2 ) at δ 4.2. − These peaks were identified in all copolymers, and the monomer compositions of the copolymers were found from the integrated peak areas, according to the following equation y m = 2 a m 3 a b 1 + 2 a m 3 a b where y m is the mole fraction of MMA in the copolymer, a m is the methoxy peak area, a b is the ethyleneoxy peak area, and the factor 2/3 arises from the ratio of protons of the specific identifying groups …”

“…The BA shows a triplet peak corresponding to the ethyleneoxy of the ester linkage (-OCH 2 ) at δ 4.2. [31][32][33] These peaks were identified in all copolymers, and the monomer compositions of the copolymers were found from the integrated peak areas, according to the following equation 34 y m )…”

“…where y m is the mole fraction of MMA in the copolymer, a m is the methoxy peak area, a b is the ethyleneoxy peak area, and the factor 2/3 arises from the ratio of protons of the specific identifying groups. 32 The reactivity ratio of the monomer was determined from the polymer NMR composition data by using the Fineman-Ross method. 35 At low conversions, the copolymer composition is described by the copolymer equation…”

Recent advances on pyrene-based photoinitiators of polymerization

“…[129] Access to azapolyacenes is also possible with pyrene, by oxidation of the adjacent aromatic rings, enabling to prepare pyrene-diones or pyrene-tetraones. [130] Historically, 1-(bromoacetyl)pyrene (Pyr_2) which is a derivative of pyrene (Pyr_1) has been extensively studied by Daswal and coworkers as a UV-photoinitiator for the copolymerization of styrene with n-butyl acrylate, [131] methyl methacrylate [132] or acrylonitrile in solution (See Figure 4). [133] In these different studies, modification of the substitution pattern of pyrene was determined as strongly influencing the reactivity of the pyrene.…”