Synthesis and Characterization of Isobornyl Acrylate and Methacrylate-N-Methyl Acrylamide Copolymers

Abstract

Free radical copolymerization of N-metbyl acrylamide (NMA)
with isobornyl acrylate (IBA) and isobornyl methacrylate (IBM)
has been investigated in N,N' -dimethyl formamide (DMF) at
60 ± 1°C using 2,2'-azobisisobutyronitrile (AIBN) as an initiator by
¹H NMR analysis. The monomer reactivity ratios were computed
by both Fineman-Ross (F-R) and Kelen-Tudos (K-T) methods. The
molecular weights of the copolymers were determined by gel permeation
chromatography. The solubility parameters were determined
with viscometric method. The glass transition temperatures
of the copolymers were determined by differential scanning calorimetry.
Thermogravimetric analysis of the copolymers was performed
and their thermal stabilities were studied. The dielectric
properties of the copolymers were also studied. The reactivity of
acrylate was found to be more than that of methacrylate towards
NMA. The reactivity ratio values suggest the formation of random
copolymers which has been supported by the azeotropic composition
evaluation. The molecular weights of the copolymers increase
with the increase of the amide content. The solubility parameter
values of acrylate copolymer are more than the corresponding methacrylate
copolymer. The T_g values of actylate copolymers are less
than the corresponding methacrylate copolymers. Thermal stability
of IBM coplymers is found to be more than that of IBA copolymers.
The dielectric loss of the copolymers is found to be shifting to a
higher temperature from acrylate to methacrylate copolymers.