R. Hu et al., INTERFACIAL ASPECTS OF LATEX IPNS FOR TOUGHENING POLYCARBONATE .1. SYNTHESIS AND CHARACTERIZATION, Journal of applied polymer science, 58(2), 1995, pp. 375-384
Core/shell structured latex particles with an interpenetrating polymer
network (IPN) core (polymer A and polymer B) and glassy shell (polyme
r C) were synthesized by emulsion polymerization techniques. Polymer A
was poly(butadiene-stat-styrene) (90/10) (P(Bd/S)). Polymer B was eit
her poly(butyl acrylate-stat-methyl methacrylate) (60/40) or poly(buty
l acrylate-stat-styrene) (60/40) prepared by a sequential IPN techniqu
e to form the cores. The glass transition temperatures, T-g, of polyme
r A and polymer B were around -70 and 10 degrees C, respectively. The
shell, polymer C, poly(styrene-stat-acrylonitrile) (72/28), was polyme
rized with grafting onto the IPN core by a semicontinuous process. The
particle size and particle size distribution were measured by light-s
cattering, capillary hydrodynamic fractionation, and transmission elec
tron microscopy. The glass transition temperatures were determined by
differential scanning calorimetry. The polymer A (particle sizes betwe
en 200-270 nm) with different gel fractions was used to characterize t
he effect of gel fraction on IPN morphology. A core/shell type phase s
eparation was observed for IPN particles when using a polymer A with >
90% gel fraction. A distribution of polymer B domains in polymer A wa
s obtained when using polymer A with a 40% gel fraction. A good covera
ge of polymer C on the IPN core particles was obtained at a core/shell
ratio of one to one. A broad glass transition range for the core/shel
l structured latex particles was observed. In article II of this serie
s, these latex particles will be used to toughen such engineering ther
moplastics as polycarbonates to understand the particular toughening t
heories of these polymers. (C) 1995 John Wiley & Sons, Inc.