Functionalized polyphosphazene and atom transfer radical polymerization of methyl methacrylate with supported and low molecular weight polyethylene ligand system for copper removal

Two different approaches using supported catalyst ligands for copper removal of atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) were explored in this study. A Schiff base ligand was covalently bonded to different solid support materials, such as silica gel, glass beads and crosslinked polystyrene. ATRP of MMA using this type of supported ligands gave PMMA with a polydispersity range from 1.34 to 1.59 and some control over molecular weight. Low molecular weight polyethylene (PE) was prepared from ylides and end-capped with appropriate ligands. ATRP of MMA using this ligand gave a good molecular weight control and polydispersities of PMMA ranging from 1.3–1.5. The system presents a homogeneous system at elevated reaction temperature and offers the possibility of performing ATRP without additional steps of removing metal contamination. The elemental analysis of PMMA polymer showed less than 2.5% of the original copper remained in the products after precipitation of PE-ligands.; In addition, polyphosphazenes with phenolic functional groups were synthesized and used as chemical sensors with nerve agent simulant, dimethyl methylphosphonate (DMMP). The polymer precursor, poly(dichlorophosphazenes), were obtained via ring opening polymerization of hexachlorocyclotriphosphazenes with (PhO) ₃P=O-BCl₃ as catalyst. The precursor was reacted with phenol-protected reagents and was followed by de-protection reaction with BBr₃ to obtain polyphosphazenes with phenol functional groups. The phenol-substituted polymer were used as the sensor platform. The simulation test with DMMP were performed and showed a detectable concentration of DMMP as low as 24 ppb.