Preparation and properties of PVC/PMMA-g-imogolite nanohybrid via surface-initiated radical polymerization

Poly(methyl methacrylate) (PMMA) grafted imogolite clay nanotubes (PMMA-g-imogolite) were prepared through activators regenerated by electron transfer for atom transfer radical polymerization (ARGET ATRP) by developing a water soluble amphiphilic ATRP initiator, which carries both an initiator moiety and a surface-attachable phosphate group. Poly(vinyl chloride)/PMMA-g-imogolite nanohybrid was prepared by using this PMMA grafted imogolite. The structure and properties of the prepared nanohybrid were characterized by differential scanning calorimetry (DSC), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and tensile test. DSC and TEM results indicate that well-dispersed PMMA-g-imogolite dominates in the nanohybrid, in spite of some imogolite rich regions. SEM observation of the fracture surfaces and the fractured films reveals that the interfacial adhesion between PMMA grafted imogolite and the matrix may be weak or strong with respect to the cohesive energy of the poly(vinyl chloride) (PVC) matrix, depending on the environmental temperature. In liquid nitrogen or at room temperature, the interfacial adhesion between PMMA grafted imogolite and the matrix is weaker, while at 90 °C, is stronger than the cohesion of the PVC matrix. In accordance with the interfacial performance, the nanohybrid shows inferior tensile performance at room temperature; whereas, superior tensile performance at 90 °C compared with the pristine PVC.