Hyperbranched aliphatic polyester grafted attapulgite via a melt polycondensation process

A new process for the facile fabrication of the hyperbranched polymer grafted nano-surfaces was developed in the present work. The AB2 type monomer, 2, 2-bis(hydroxymethyl)propionic acid (bis-MPA), was successfully grafted from the surfaces of the amino groups modified attapulgite nano-fibrillar clay (amino-ATP) via a melt polycondensation method with p-toluenesulfonic acid (p-TSA) as catalyst. Higher percentage of grafting (PG%) was achieved within shorter polymerizing time, compared with the product from the solution polycondensation method within longer polymerizing time. The surface composition and crystal structure of the hyperbranched aliphatic polyester grafted attapulgite (HAPE-ATP) were also characterized by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The transmission electron microscopy (TEM) analysis results showed that the dispersibility of the nano-fibrillar clay in organic solvent was improved after the graft polymerization.