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Preparation of Scratch and Abrasion Resistant Polymeric Nanocomposites by Monomer Grafting onto Nanoparticles, 3. Effect of Filler Particles and Grafting Agents
Author(s) -
Bauer Frank,
Sauerland Volker,
Gläsel HansJürgen,
Ernst Horst,
Findeisen Matthias,
Hartmann Eberhard,
Langguth Helmut,
Marquardt Bärbel,
Mehnert Reiner
Publication year - 2002
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/1439-2054(20020801)287:8<546::aid-mame546>3.0.co;2-w
Subject(s) - materials science , grafting , filler (materials) , nanocomposite , monomer , abrasion (mechanical) , nanoparticle , composite material , scratch , polymer science , chemical engineering , polymer chemistry , polymer , nanotechnology , engineering
After modification with different trialkoxysilanes, nano‐sized silica and alumina particles were used as fillers in transparent UV/EB curable acrylates for polymer reinforcement, particularly to attain scratch and abrasion resistant coatings. The acid catalyzed condensation of the organosilanes forms a polysiloxane shell which covers the nanoparticle like a nanocapsule. CP MAS NMR spectroscopy and MALDI‐TOF mass spectrometry proved to be useful for the characterization of the polysiloxane structures. Grafted oligomers with more than 20 monomeric units were observed. Nanoparticles modified by methacroyloxy(propyl)trimethoxysilane and vinyltrimethoxysilane can copolymerize with acrylates. Compared with the pure polymers, these crosslinked polyacrylate nanocomposites, containing up to 35 wt.‐% silica, exhibit markedly improved surface mechanical properties. Promising scratch and abrasion resistance of radiation‐cured nanocomposite materials were also obtained by propyltrimethoxysilane grafting which results in an organophilation of pyrogenic silica. Both colloidal and pyrogenic nano‐sized silica nanopowders were used as fillers in polyacrylate films. The concentration of colloidal SiO 2 in commercial acrylate formulations amounts up to 50 wt.‐%, whereas pyrogenic silica, notwithstanding their surface modification by silanes, results in a thickening effect which limits its content to about 35 wt.‐%. Nevertheless, a comparison showed a distinct improvement in the surface mechanical properties such as haze and diamond microscratch hardness for surface‐modified pyrogenic silica.