Environmentally-Friendly Acrylates-Based Polymer Latices - Advanced Materials for Agriculture, Food and Environmental Safety - page 164

Bryjak [137] evaluated BA copolymerizd with EGDMA as potential
chromatographic packings. It was found that slightly crosslinked copoly-
mers (up to 30 wt% EGDMA) did not provide porous material, while for
matrices which exceeded 40 wt% of EGDMA the porous structure remained
unchangeable. h e increase of crosslinker content greatly af ected the sur-
face hydrophobicity.
Copolymer systems based on various molar ratios of MMA/BA and dif-
ferent mass content of N-methylolacrylamide (NMA) as a cross-linking
agent were investigated by Leskovac et al. [138]. h e changes in mechanical
properties of the copolymers were found to be connected with the cross-
linking and/or degradation mechanism. It was concluded that a higher
content of MMA units can lead to preferential depolymerization; whereas
an opposite ef ect was observed when BA contents increased. h e observed
changes in mechanical properties were reduction of yield point, strength,
elongation, and increase in brittleness, and may be attributed to the pres-
ence of various ratios of constitutive sequences and crosslinked structures
before and at er degradation.
Copolymers of BA-MMA-AA and intraparticle crosslinking agents con-
taining NMA and EGDMA were prepared by emulsion copolymerization
by Yoo et al. [58] h e i lms were prepared from the mixture of copoly-
mers and the interparticle crosslinking agents which were prepared from
hexamethylene diisocyanate and aziridine ethanol. h e i lm was cast using
mixtures of the copolymer and the interparticle crosslinking agent, and
crosslinked in a convection oven. h e ef ects of the contents of the intra/
interparticle crosslinking agents were evaluated. By increasing the contents
of EGDMA, the roughness of the i lms was increased because of the ef ects
of EGDMA which acted as an intraparticle crosslinking agent. By increas-
ing the contents of the interparticle crosslinking agent, roughness was also
increased by the reaction between the copolymers and interparticle cross-
linking agent. Tensile strength, water and chemical resistance of the i lms
were increased, whereas elongation of the i lm was decreased by increasing
the content of interparticle crosslinking agents.
To determine the dif erence in tensile properties and swelling behav-
ior, a series of crosslinking monomers such as macromonomer crosslinker
(Mac), EGDMA and aliphatic urethane acrylate were copolymerized with
BMA by emulsion technique by El-Aasser et al. [59]. h ey found that
copolymers prepared with Mac were tough in comparison with copoly-
mers made with EGDMA. h e factors responsible for the dif erence were
the presence of longer linear or lightly crosslinked PBMA chains and
the looseness of the crosslinked network structure in the PBMA-co-Mac
copolymers.