Effects of Filler Particle/Elastomer Distribution and Interaction on Composite Mechanical Properties

Abstract

Some new characterization results are reported for composites prepared from methyl acrylate monomer and from reinforcing silica particles at various degrees of dispersion. In some cases, 3-(trimethoxysilyl)propyl methacrylate groups were grafted onto the silica (PMA) through participation in the methyl acrylate polymerization used to form an elastomeric PMA matrix. In some cases, the usual random dispersion of the silica particles was "aged" or converted into regular arrays within the monomer prior to its polymerization. As an alternative, placing chloropropyltrimethoxysilane groups on the particle surfaces was used to obtain random arrangements in which the strong bonding between the particles and elastomer was suppressed. In another approach, the particle dispersion was first dried and then blended into the monomer before its polymerization, thereby giving an aggregated arrangement. These various composites were characterized with regard to their mechanical properties in elongation (using techniques allowing a close appproach to elastic equilibrium), and with regard to chain orientation (using birefringence measurements and infrared spectroscopy). The elastomers having randomly dispersed and regularly dispersed silica dispersions were very similar in mechanical properties and chain orientation, but extensibility was significantly improved by decreasing the strength of the particle-elastomer bonding. Additional improvements in extensibility, and associated increases in toughness, were obtained when these same particles were aggregated.

Nanoparticle amount, and not size, determines chain alignment and nonlinear hardening in polymer nanocomposites

“…on either mechanical strain hardening (13)(14)(15)(16) or chain alignment (17)(18)(19)(20), but not both.…”

“…Raman spectra at each « eng were recorded as A ∥ or A ⊥ , depending on whether the laser polarization was parallel or perpendicular, respectively, to the stretching direction. We calculated the hP 2 i coefficient from these amplitudes and refer to this coefficient as the molecular order parameter, 18,32). S mol is zero for a perfectly isotropic vibration.…”

Metal Acetylacetonates Covalently Anchored onto Amine Functionalized Silica/Starch Composite for the One-Pot Thioetherification and Synthesis of 2H-Indazoles

“…Nowadays, catalysts based on silica/biomaterial composites are being used to meet the practical catalytic requirements in the chemical industry. The combination of high surface area inorganic mesoporous materials with organic polymer systems is an emerging class of hybrid materials with numerous potential applications [12][13][14][15][16][17][18]. They combine the advantages of inorganic material (rigidity, thermal stability) and the organic polymer (e.g., flexibility, ductility, and processability).…”

Polymer-clay Nano Composites

“…TEM allows a qualitative understanding of the internal structural, spatial distribution of the various phases, and views of the defects in the structure directly.TEM observations reveal coexistence of nano clay material in the intercalated and the exfoliated states. Intercalated layers or structures are referred to as where the inorganic layers maintain the parallel registry of pristine clay material and are separated by ultrathin polymeric films [43][44][45][46] . Thermal properties have been evaluated through DSC and mechanical properties using uniaxial tensile testing machines 47,48 .…”