Copolymerization of methyl methacrylate and allyl acetate Part I. Rate of reaction

Free radical bulk copolymerization of methyl methacrylate (MMA) and allyl a cetate (AAc) has been investigated using electron spin resonance (ESR) and FT-near infrared (FTNIR) spectroscopy. Data are used to evaluate the rate c onstants. The mole fraction of AAc plays an important role in the copolymer ization of these two monomers. AAc not only delays the Trommsdorff effect b ut also increases the onset of percentage total conversion at which the Tro mmsdorff region begins. With AAc fraction 0.5 and higher, no Trommsdorff ef fect was observed. Inclusion of AAc into copolymer structure mainly occurs in the Trommsdorf region or when the AAc fraction in the comonomer feed is dominant. This is associated with a drop in the concentration of propagatin g radicals. However, ESR spectra indicate that the MMA propagating radical is predominant during the reaction. In the comonomer mixtures where a Tromm sdorff region can be observed, the addition of AAc does not produce any sig nificant change in k(p) and k(t) in the steady state region. Major changes in k(p) and k(t) are observed after the gel point and glassy state, respect ively. (C) 2001 Society of Chemical Industry.