Tri-ammonium end functional polyethylene: facile synthesis and application as an intercalation agent

Organo-modification of montmorillonite (MMT) is crucial for the promotion of a fine dispersion of MMT into an (often hydrophobic) polymer matrix. Ammonium-terminated polymers are more efficient in modifying clay compared to small organic cations such as alkyl ammoniums or side functionalized polymers. Herein, tri-amino end functional polyethylene (PE-3 N) with low molecular weight was first synthesized via an efficient and robust epoxide ring-opening reaction by treating epoxide-terminated PE with diethylenetriamine. The chemical structure of PE-3 N was unambitiously characterized by chromatographic and spectral methods. By reacting with excess HCl, PE-3 N was subsequently converted to tri-ammonium end functional polyethylene (PE-3 N + ), which serves as an intercalation agent of MMT. By adjusting the weight ratio of PE-3 N + to pristine MMT ( R P/M ) applied in the static melt intercalation process, correlations between the extent of exfoliation and R P/M were successfully established. XRD results revealed that complete exfoliation of MMT could be afforded with R P/M as low as 1, which is the lowest value ever reported for ammonium-terminated polymers applied as intercalation agents. SEM micrographs showed that MMT sheets were swollen by PE-3 N + , affirming the successful modification of MMT. The PE modified MMT obtained may find application in preparing high-performance PE/MMT nanocomposites. © 2017 Society of Chemical Industry