writer：Fa-Ai Zhang*, Jian-Shu Kang, Min Luo, Cai-Li Yu
keywords：Styrene-acrylate emulsion, Polymerizable emulsifier, Nano-SiO2 colloid, hardness
source：期刊
specific source：Iranian Polymer Journal
Issue time：2012年
Soapless emulsion polymerization of styrenebutyl
acrylate-acrylic acid was carried out using single or
combined polymerizable emulsifiers, such as hydroxypropyl
methacrylate sodium sulfate (HPMAS), sodium vinyl
sulfate, and vinyl alkylphenol polyether sulfates (NRS-10),
in the presence of colloidal nano-SiO2 solution in order to
obtain films with high degree of hardness and water-resistance.
Monomer conversion, formation of coagulum, viscosity,
particle size, size distribution, and surface tension of
the emulsions, as well as the film properties, were determined
and compared with those of an emulsion prepared
with the conventional emulsifier sodium dodecyl sulfate
and polyoxyethylene octylphenol ether. Emulsions prepared
from a mixture of two polymerizable emulsifiers
NRS-10 and HPMAS (1:1, weight ratio) have presented
high monomer conversion, low coagulum, and small particle
sizes. When the emulsifier level increased within
a certain level, the monomer conversion increased but
particles size decreased. Increased amounts of reactive
emulsifiers led to low monomer conversion, large amount of
coagulum and small particle sizes. With the increase of
nano-SiO2 the particle sizes and the viscosity of the emulsion
also increased. The introduction of reactive emulsifiers
improved the water-resistance of the resulting films, and the
addition of nano-SiO2 increased the hardness of the coatings.
Under optimal conditions, the coatings made from
emulsions produced from a combination of reactive emulsifiers
such as NRS-10 and HPMAS (1:1, weight ratio) at2 % level (based on monomer weight) exhibited remarkable
hardness, adhesion force and water-resistance