Attapulgite (ATP) hybrid particles were prepared via a simultaneous reverse and normal initiation atom transfer radical polymerization (SR&NI ATRP). ATP was first activated with hydrochloric acid to enhance the surface reactivity

and γ-aminopropyltriethoxysilane (APTES) was chemically bounded on the surface of ATP (ATP-APTES) via dealcoholization reaction. Then

ATP with ATRP initiating groups (ATP-Br) was prepared by amidation reaction between ATP-APTES and α-bromoisobutyryl bromide. Finally

SR&NI ATRP of styrene was conducted using copper bromide (CuBr2) complex tris(2-(dimethylamino)ethyl)amine (Me6-TREN) as the highly active catalytic system

initiated by 2

2-azobis(isobutyronitrile) (AIBN) and ATP-Br as a dual-component initiation system

and hybrid ATP particles grafted with polystyrene (ATP@PS) was obtained. The whole procedure was traced by gas chromatography (GC)

Fourier transform infrared spectroscopy (FTIR)

thermo gravimetric analysis (TGA)

and X-ray photoelectron electron microscopy (TEM) in detail. The effects of different molar ratio of catalyst on the first-order kinetic behavior were investigated. The experimental results showed that polymerization of styrene under the AIBN-α-bromo amide initiation system and CuBr2/Me6-TREN catalyst displayed the living/controlled nature. As the increase of molar ratio of catalyst

the polymerization was deviated from the first-order kinetic prematurely

and the initiating efficiency was enhanced. When polymerization was performed at 80℃ under the ratio value of [St]/[CuBr2/Me6-TREN]/[AIBN]/[ATP-Br]=200/0.3/0.05/0.5

both of the molecular weight of grafted and free PS were grown in a controlled manner with a lower PDI (<1.54)

and the difference of them was increased with conversion increasing. When proceeded SR&NI ATRP with 31.1% monomer conversion

the initiating efficiency was calculated to be 6.3%

and about 1.4 g·g-1 grafting ratio of hybrid particles was achieved. The thickness of grafted layer was attained to about 14 nm. Simultaneously

inhomogeneous distribution was observed

which resulted from the coupling termination between the surface-anchored and free active sites. The dispersion property of ATP@PS in PS matrix was improved obviously.