Comparative studies of the solution properties of vinyl aromatic polymers Final report

Viscosity and nuclear magnetic resonance studies of vinyl aromatic polymer solution

Study of solution properties of block copolymers Final report

Solution properties of polybutadiene and polystyrene block copolymer

On the toughness of thermoplastic polymer nanocomposites as assessed by the essential work of fracture (EWF) approach

The essential work of fracture (EWF) approach is widely used to determine the plane stress fracture toughness of highly ductile polymers and related systems. To shed light on how the toughness is affected by nanofillers EWF-suited model polymers, viz. amorphous copolyester and polypropylene block copolymer were modified by multiwall carbon nanotube (MWCNT), graphene (GR), boehmite alumina (BA), and organoclay (MMT) in 1 wt% each. EWF tests were performed on deeply double-edge notched tensile-loaded specimens under quasistatic loading conditions. Data reduction occurred by energy partitioning between yielding and necking/tearing. The EWF prerequisites were not met with the nanocomposites containing MWCNT and GR by contrast to those with MMT and BA. Accordingly, the toughness of nanocomposites with homogeneously dispersed and low aspect ratio fillers may be properly determined using the EWF. Results indicated that incorporation of nanofillers may result in an adverse effect between the specific essential and non-essential EWF parameters

Nanodielectics (A "Universal" Panacea for Solving All Electrical Insualation Problems?)

This text summarizes the keynote presentation that is based on the full-length paper of the same title. Dr. Fréchette's oral presentation should not be seen as a summary of the “Brainstorm paper” but a glance at some major accomplishments, hinrances and still remaining questions relative to nanodielectrics. Are nanodielectrics a “universal” panacea? The answer to that question is no - but they've got a lot of potential

Free Volume of Molten and Glassy Polystyrene and Its Nanocomposites

Peer reviewed: YesNRC publication: Ye

Equations of state for polyamide-6 and its nanocomposites. 1. Fundamentals and the matrix

The pressure-volume-temperature (PVT) surface of polyamide-6 (PA-6) was determined in the range of temperature T = 300\u2013600 K and pressure P = 0.1\u2013190 MPa. The data were analyzed separately for the molten and the noncrystalline phase using the Simha-Somcynsky (S-S) equation of state (eos) based on the cell-hole theory. At Tg(P) 64 T 64 Tm(P), the \u2018\u2018solid\u2019\u2019 state comprises liquid phase with crystals dispersed in it. The PVT behavior of the latter phase was described using Midha-Nanda-Simha- Jain (MNSJ) eos based on the cell theory. The data fitting to these two theories yielded two sets of the Lennard-Jones interaction parameters: e*(S-S) = 34.0 \ub1 0.3 and e*(MNSJ) = 22.8 \ub1 0.3 kJ/mol, whereas v*(S-S) = 32.00 \ub1 0.1 and v*(MNSJ) = 27.9 \ub1 0.2 mL/mol. The raw PVT data were numerically differentiated to obtain the thermal expansion and compressibility coefficients, \u3b1 and \u39a, respectively. At constant P, j followed the same dependence on both sides of the melting zone near Tm. By contrast, \u3b1 = \u3b1(T) dependencies were dramatically different for the solid and molten phase; at T < Tm, \u3b1 linearly increased with increasing T, then within the melting zone, its value step-wise decreased, to slowly increase at higher temperatures.NRC publication: Ye

A multi-agent approach to the optimization of Intelligent Buildings Energy Management

The existing installations in buildings form a specific kind of mazes that are overcome by factors that are dedicated to them (heat, water, electricity, etc.) The present systems attempt to distribute sources in such buildings to the receivers as well as they can. The most sophisticated ones are based on the Building (Energy) Management Systems, i.e. BEMS located in modern intelligent buildings. The article proposes a new approach to the existing grids with the ant colony optimization (ACO). ACO agents are effective in overcoming existing grids. But they do need modification of their standard algorithms or parsed grids for energy savings. These questions constitute the hypothesis taken under examination. The expected solution is a challenge for different ACO techniques with an evolutionary or aggressive approach taken into consideration. Different opportunities create many latent patterns to recover, evaluate and rate. They can be recovered in nondeterministic polynomial time, but they occur as NP-hard problems, so they can consume a lot of time to be solved. It is extremely important to formulate more aggressive ways to find an approximation of the optimal pattern within an acceptable time frame. The options taken under examination show that there are a few interesting approaches to accelerate the ACO and reveal a solution in real time. In the article the results are presented as the results of the research

Viscoelastic Phase Separation in Shear Flow

We numerically investigate viscoelastic phase separation in polymer solutions under shear using a time-dependent Ginzburg-Landau model. The gross variables in our model are the polymer volume fraction and a conformation tensor. The latter represents chain deformations and relaxes slowly on the rheological time giving rise to a large viscoelastic stress. The polymer and the solvent obey two-fluid dynamics in which the viscoelastic stress acts asymmetrically on the polymer and, as a result, the stress and the diffusion are dynamically coupled. Below the coexistence curve, interfaces appear with increasing the quench depth and the solvent regions act as a lubricant. In these cases the composition heterogeneity causes more enhanced viscoelastic heterogeneity and the macroscopic stress is decreased at fixed applied shear rate. We find steady two-phase states composed of the polymer-rich and solvent-rich regions, where the characteristic domain size is inversely proportional to the average shear stress for various shear rates. The deviatoric stress components exhibit large temporal fluctuations. The normal stress difference can take negative values transiently at weak shear.Comment: 16pages, 16figures, to be published in Phys.Rev.

Green Machining of a Thermoplastic Ceramic-Ethylene Ethyl Acrylate/Isobutyl Methacrylate Compound

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65870/1/j.1551-2916.2004.01575.x.pd