Synthesis of ultrahigh molecular weight poly(butyl acrylate) in the presence of palladium nanoparticles

In this paper, the polymerization of butyl acrylate (BA) in the presence of palladium nanoparticles (Pd NPs) has been investigated. A series of organic halides such as carbon tetrachloride (CCl 4 ), ethyl 2-bromopropionate (EBP), ethyl 2-chloropropionate (ECP) and ethyl α-bromophenylacetate (α-EBP) were employed to initiate the polymerization of BA in the presence of Pd NPs. An ultrahigh molecular weight poly(butyl acrylate) (PBA) with a number average molecular weight ( M n ) up to 1.86 × 10 6  Da and polydispersity index (PDI) of 2.38 was synthesized by using α-EBP as an initiator in the presence of 10.5 ppm of Pd NPs at 60 ºC. The orders of polymerization with respect to α-EBP, Pd NPs and BA were determined to be 0.48, 0.86, and 0.95 respectively according to the kinetic investigation. A mechanistic investigation revealed that the reaction of α-EBP and Pd NPs resulted in a generation of α-EBP residue radical to initiate the polymerization of BA around the surface of Pd NPs.