A new and simplistic method

ultrasonic irradiation technique was employed to prepared poly(n—butyl acrylate-co-methyl methacrylate-co-methacrylic acid)[P(BA—MMA—AA)]／TiO2 nanocomposites．By taking advantage of the multiple effect of ultrasound

such as dispersion

pulverization

activation and initiation

the aggregates of TiO2 particles can be broken down．The polymerization of monomers BA

MMA

and functional monomer AA proceeded while TiO2 particles were redispersed by ultrasound．The stable P(BA-MMA-AA)／TiO2 nanocomposite emulsion was obtained．The effects of several main factors

such as surfactant concentration

monomers concentration and the amount of TiO2

on polymerization rate were investigated．The experimental results showed that with increase in SDS surfactant concentration and decrease in monomers concentration and the amount of TiO2 the polymerization rate increased．TEM

SEM and FTIR analyses confirmed that polymers were present on TiO2 surface

and there was strong interaction between TiO2 and polymers with carhoxylic functional groups．DSC

GPC

1H-NMR characterizations showed that with the introduction of TiO2

the average molecular weight of the obtained copolymer decreased

molecular weight distribution became wide．and the BA content of copolymer chains increased compared to that of the pure copelymer

resulting in lower Tg．This method has the following advantages

(1)aqueous medium

(2) without any additional chemical initiator

(3)lower reaction temperature

usually near ambient temperature

(4)ease of operating and(5)the encapsulated polymer layer can be well designed to meet different requirements．