Environmentally-Friendly Acrylates-Based Polymer Latices - Advanced Materials for Agriculture, Food and Environmental Safety - page 151

transition temperature, mechanical properties, and solvent resistance)
of the resulting copolymer can be controlled by choosing an appropriate
comonomer system, such as BMA, MMA, styrene, etc.

6.1.4.2 Copolymers of Acrylic Esters

Acrylic copolymers are the copolymers obtained from the polymerization of
esters derived from monohydric alcohols with acrylic acid, methacrylic acid,
or lower alkyl substituted acrylic acids. Copolymerization of MMA with
monomers such as ethyl-, butyl-, isobutyl-, 2-ethylhexyl-, 2-hydroxyethyl-,
dodecyl- and cetyl-methacrylates has been investigated in the past with an
aim to study the ef ect of structure on the properties of copolymers [15-22].
Bulk polymerizations of MMA with n-hexyl acrylate (HA) or EHA
were carried out using benzoyl peroxide as initiator by Varma et al. [23].
Polymer samples were prepared using HA or EHA from 0 to 1 mole frac-
tion in the initial feed. Molecular characterization of the copolymers and
homopolymers was done by gel permeation chromatography (GPC) and
intrinsic viscosity measurements. To determine the copolymer composi-
tions, 1 H-NMR spectroscopy was used.
Li et al. [24] made an experimental investigation of the kinetics of bulk
polymerization of MMA and ethylene glycol dimethacrylate (EGDMA)
initiated with Azobisisobutyronitrile (AIBN) at 70

C. h ey covered a wide
range of divinyl-vinyl monomer ratios and determined the ef ect of chain
transfer agent concentration on the gel point conversion.
Rouhallah and Ali-Asghar [25] prepared a series of acrylic copolymer
solutions by copolymerizing MMA with BA in toluene to high conversion
using dibenzoyl peroxide as initiator. Various reaction parameters, such as
MMA concentration and mode of addition of reactants to the reaction ves-
sel, were changed to obtain an acceptable quality of the resin for paint. h e
properties of the resin and the ef ect of MMA concentration on properties
(viscosity, drying time, hardness and adhesion) were measured according
to ASTM standard tests. A linear relation between i nal percentage con-
version and MMA concentration was observed. Drying time, hardness,
and Tg of the samples increased with MMA concentration; adhesion of
the sample remained constant up to 50 wt% of MMA and then decreased
signii cantly with further increase in MMA concentration.
Jang and Kim [26] synthesized copolymers of styrene with EHA,
LA, lauryl methacrylate (LMA), and stearyl acrylate (SA) by suspension
polymerization technique using benzoyl peroxide (BPO) as an initiator
with a varying monomer feed ratio. h e copolymers were characterized
by FTIR, 1 H-NMR, DSC, and a solubility test, and they were random in

°