Properties of polystyrene and polymethyl methacrylate copolymers of polyhedral oligomeric silsesquioxanes: A molecular dynamics study

Abstract

Molecular dynamics simulations were carried out on copolymers of both styrene and methyl methacrylate with polyhedral oligomeric silsesquioxane (POSS) derivatives to identify the origin of the property changes imparted upon the chemical incorporation of POSS. Simulations were carried out on these hybrid copolymers and the parent homopolymers to elucidate the effect of the T 8 , T 10 , and T 12 POSS cages. These POSS comonomers were derivatized with a single polymerizable function and 7, 9, and 11 nonpolymerizable hydrocarbon moieties, respectively. Glass transition temperatures (T g ) were computed from specific volume versus temperature plots. The packing of POSS units around the polymer backbone was analyzed via their radial distribution functions. The effect of POSS on polymer motion was analyzed through the mean square displacement function. The improvements in the elastic moduli upon incorporation of POSS were computed by employing the static deformation method. V V C 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 234-248, 2006

Surface energetics, dispersion, and nanotribomechanical behavior of POSS/PP hybrid nanocomposites

“…In general, hybridization of an organic polymer matrix with inorganic POSS results in improved thermal and mechanical properties along with increase in oxidative and flame resistance. [3][4][5][6][7][8]11 Recently Nanda et al 12 synthesized well dispersed polyurethane/POSS hybrid materials utilizing a solution polymerization process. Ordered morphologies with homogenously distributed POSS domains ($100-150 nm) were observed.…”

“…Over the last decade POSS has been copolymerized with multiple monomer systems to produce a wide range of thermoplastics and thermosets with POSS molecules incorporated as an integral part of the polymer chain. [1][2][3][4][5][6][7][8][9] The majority of these research efforts are focused on improving thermomechanical performance of the polymer matrix through uniform molecular level POSS nanoparticle dispersion achieved by directly incorporating POSS moieties into the polymer chain. 9,10 Thermomechanical properties are reported to be strongly influenced by the structure and concentration of the POSS moieties, POSS-POSS interactions and POSS-polymer interactions.…”

The influence of POSS nanoparticles on selected thermal properties of polyurethane-based hybrids

“…Unlike a filled hybrid system or blend, however, proper functionalization of POSS may limit aggregation due to covalent attachment to the PU backbone, or an appropriate choice of non-reactive R-groups, may prevent aggregation beyond a scale of ca. one radius of gyration [53][54][55][56][57]. The resulting effect on physicochemical properties will vary with the silsesquioxane moieties dispersion or the aggregation level.…”

“…The resulting effect on physicochemical properties will vary with the silsesquioxane moieties dispersion or the aggregation level. Therefore, it is of crucial importance to understand the nanostructure-property-processing relationships for given hybrid systems in order to successfully tailor properties to intended applications [53][54][55][56][57]. Most inorganic ceramic or silica particles are immiscible in organic systems because of poor specific interactions within these organic-inorganic hybrid systems and the negligibly small combined entropy contribution to the free energy of homogenization.…”

Characterizing and Modeling Mechanical Properties of Nanocomposites-Review and Evaluation

“…In 1997, Cornwell et al used molecular dynamics to predict the elastic properties of single-walled carbon nanotubes [101]. In recent years, molecular dynamics simulation has been extensively used in predicting mechanical properties of carbon nanotubes and nanotubes reinforced composites [102][103][104][105][106][107][108][109], graphite/epoxy nanocomposites [110][111][112], and other nanocomposites [113][114][115][116][117][118][119].…”