Reactivity ratios and sequence structures of the copolymers prepared using photo‐induced copolymerization of MMA with MTMP

Abstract

4-Methacryloyl-2,2,6,6-tetramethyl-piperidine (MTMP) was applied as reactive hindered amine piperidine. Photo-induced copolymerization of methyl methacrylate (MMA, M(1)) with MTMP (M(2)) was carried out in benzene solution at ambient temperature. The reactivity ratios for these monomers were measured by running a series of reactions at various feed ratios of initial monomers, and the monomer incorporation into copolymer was determined using (1)H NMR. Reactivity ratios of the MMA/MTMP system were measured to be r(1)= 0.37 and r(2)= 1.14 from extended Kelen-Tüdos method. The results show that monomer MTMP prefers homopolymerization to copolymerization in the system, whereas monomer MMA prefers copolymerization to homopolymerization. Sequence structures of the MMA/MTMP copolymers were characterized using (1)H NMR. The results show that the sequence structure for the main chain of the MMA/MTMP copolymers is mainly composed of a syndiotactic configuration, only with a little heterotactic configuration. Three kinds of the sequences of rr, rr', and lr' in the syndiotactic configuration are found. The sequence-length distribution in the MMA/MTMP copolymers is also obtained. For f(1)= 0.2, the monomer unit of MMA is mostly separated by MTMP units, and for f(1)= 0.6, the alternating tendency prevails and a large number of mono-sequences are formed; further up to f(1)= 0.8, the monomer unit of MTMP with the sequence of one unit is interspersed among the chain of MMA.

Photoinduced Copolymerization of APMP-MMA: The Role of Reactive Hindered Amine APMP

“…The 1 H NMR spectra of the poly(APMP-co-MMA) where total monomer conversion was about 0.4 were shown in Figure 2. It was shown that, with the decrement of APMP feed ratio, the peaks at 0.85 ppm which indicated the trials of MMA units [29] increased dramatically. When the feed ratio of APMP/MMA was no more than 50/50, MMA tended to form syndiotactic units.…”

“…In this paper, the reaction kinetics in the photoinduced copolymerization of APMP with methyl methacrylate (MMA) have been investigated. By the analysis of 1 H NMR spectra, the reactivity ratios of the two monomers at high monomer conversions and the sequential distribution of poly(APMP-co-MMA) have been obtained [29]. The study of this photoinduced copolymerization could be the guidance for the application of APMP derivatives as the reactive light stabilizers.…”

Phenylalanine‐Tethered pH‐Responsive Poly(2‐Hydroxyethyl Methacrylate)

“…It is essential to have precise knowledge regarding the monomer reactivity ratios for any copolymerization reaction to control/predict the copolymer composition and copolymer sequence distribution. [33] Accordingly, the reactivity ratios of HEMA and Boc-Phe-EMA in the present system were determined by virtue of extended Kelen-Tüdös method. [34] In addition, the pH-responsive properties and solubility of the deprotected copolymers were investigated via turbidity measurements.…”

“…Subsequent deprotection of the Boc‐group provides copolymers enclosing pH‐responsive primary amine pendants in the side chains. It is essential to have precise knowledge regarding the monomer reactivity ratios for any copolymerization reaction to control/predict the copolymer composition and copolymer sequence distribution [33] . Accordingly, the reactivity ratios of HEMA and Boc‐Phe‐EMA in the present system were determined by virtue of extended Kelen‐Tüdös method [34] .…”