Nanocomposites-Turned-Nanoalloys Polypropylene/Multiwalled Carbon Nanotubes-graft-Polystyrene: Synthesis and Polymer Nanoreinforcement

This paper showcases a new type of polyolefin nanocomposite where nonolefinic organic thermoplastic polymers serve as nanoscale reinforcements for polyolefins. On the basis of polypropylene/multiwalled carbon nanotubes (PP/MWCNTs) nanocomposites synthesized by in situ propylene polymerization, polypropylene/multi-walled carbon nanotubes-graft-polystyrene (PP/MWCNTs-g-PS) nanocomposites were obtained by in situ graft polymerization of styrene on the surfaces of MWCNT with the atom transfer radical polymerization (ATRP) mechanism. Confined by MVVCNTs, the grafted PS formed nanoparticles on and bonded to MVVCNTs surfaces, their sizes (10-250 nm) being primarily governed by graft lengths (molecular weights). Though no interfacial compatibilization was imposed between PP and PS, the PS nanoparticles were devoid of coarsening when the materials were annealed in melt. Grafting of PS disrupted networking of MWCNTs by pi-pi interaction. As rigid thermoplastic polymer reinforcement, the PS nanoparticles claimed a significant reinforcing effect for PP on elastic modulus in the temperature range between the glass transitions of PP and PS. This research verified that a nonolefinic organic thermoplastic polymer could serve as a nanoscale reinforcement for polyolefins in the manner of nanocomposites-turned-nanoalloys, which would greatly enrich the choices of nanoparticle materials for polyolefin modifications.

Automated summary

This research demonstrates that nonolefinic organic thermoplastic polymers can act as nanoscale reinforcement for polyolefins, enhancing the elastic modulus in a certain temperature range. By grafting polystyrene nanoparticles onto multi-walled carbon nanotubes through in situ polymerization, the materials showed no coarsening during annealing in melt.