Miscibility and mechanical properties of aryl-aliphatic polyamides/nylon 6 molecular composites

Summary A series of aryl-aliphatic polyamides, copoly(4,4-diaminobenzanilide-adipamide/2,6-naphthalamide)s, with feed mole ratios of adipic acid/2,6-naphthalene dicarboxylic acid of 1/9, 3/7, and 5/5 were synthesized. A new family of molecular composites based on the synthesized aryl-aliphatic polyamides and nylon 6 has been discovered. The molecular composites were found to have at least partial miscibility between aryl-aliphatic polyamides and nylon 6. Well-defined aryl-aliphatic polyamide microfibrils a few nanometers in diameter were observed in the molecular composites. 10 wt% aryl-aliphatic polyamide clearly promoted the toughness of nylon 6.     

"Their ideas of beauty are, on the whole, the same as ours": Consistency and variability in the cross-cultural perception of female physical attractiveness.

The consistency of physical attractiveness ratings across cultural groups was examined. In Study 1, recently arrived native Asian and Hispanic students and White Americans rated the attractiveness of Asian, Hispanic, Black, and White photographed women. The mean correlation between groups in attractiveness ratings was r?=?.93. Asians, Hispanics, and Whites were equally influenced by many facial features, but Asians were less influenced by some sexual maturity and expressive features. In Study 2, Taiwanese attractiveness ratings correlated with prior Asian, Hispanic, and American ratings, mean r?=?.91. Supporting Study 1, the Taiwanese also were less positively influenced by certain sexual maturity and expressive features. Exposure to Western media did not influence attractiveness ratings in either study. In Study 3, Black and White American men rated the attractiveness of Black female facial photos and body types. Mean facial attractiveness ratings were highly correlated (r?=?.94), but as predicted Blacks and Whites varied in judging bodies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Miscibility and Mechanical Properties of Poly(4,4′-diaminobenzanilide- 2,6-naphthalamide)/Nylon 6 Molecular Composites

Poly(4,4′-diaminobenzanilide-2,6-naphthalamide) (DBNA) was synthe-sized by reaction of 2,6-naphthalene dicarboxylic acid with 4,4′-diamino-benzanilide. A new family of molecular composites based on the synthesized DBNA and nylon 6 has been discovered. Exploratory studies were con-ducted with polymers that are soluble in a common organic solvent, N-methylpyrrolidone containing lithium chloride, so that a blend could be prepared by precipitating blended materials in solution into a non-solvent such as water. The miscibility of blends of DBNA with nylon 6 was studied using a differential scanning calorimeter, dynamic mechanical analyser and Fourier transform infrared spectrometer. The blends were found to have at least partial miscibility between DBNA and nylon 6. The morphology and mechanical properties of the molecular composites were evaluated using a scanning electron microscope, transmission electron microscope and tensile tester. The etched specimen showed microfibrils with a diameter of a few nanometres. It has been found that improvement in DBNA dispersion and mechanical properties can be obtained by blending small amounts of DBNA in nylon 6. © of SCI.     

High throughput reflective light guide for planar illuminator

A light guide fully composed of reflective plate has been proposed for a planar illuminator with the light source located at the side edge. Using mirror reflection as the light guiding mechanism increases the light acceptance angle of the light guide, and the hollow structure allows increasing the source coupling area without inducing further weight. Accompanying with the optical films, for example, a diffuser, a prismatic film, and a reflective polarizer to spread light distribution, the uniformity of the prototype has shown the feasibility for a planar illuminator.     

Capillary action-supported contactless atmospheric pressure ionization for the combined sampling and mass spectrometric analysis of biomolecules

It is proposed that a short tapered capillary can be utilized as a nanoliter-volume sampling tool and sample emitter for generation of gas-phase ions in front of the mass spectrometer, without the need for using an additional electric power supply, a gas supply, or a syringe pump. A wide range of molecules can be analyzed in pure solutions and complex matrixes (cell extract, urine, and plant tissue) with no or minimum sample preparation. Singly and multiply charged ions can be detected in either positive or negative-ion mode. Because of the nanoliter-volume sampling and low spectral background, the mass detection limit for bradykinin is in the low attomole range. Other advantages include simplicity, disposability, and low cost. The putative mechanism of the ion formation in this capillary-action supported contactless spray emitter is discussed.     

Influence of carrier injection on resistive switching of CaCu3Ti4O12 thin films with Ni electrode

The influence of electron injection on the electric-pulse-induced resistive switching of perovskite CaCu₃Ti₄O₁₂ (CCTO) films was studied by current-voltage (I-V) measurements. The electron injection was reduced by annealing the sample in an O₂ atmosphere. The switching from the high-resistance state HRS to the low-resistance state LRS by a filamentary mechanism was suppressed when the carrier injection occurs by Poole-Frenkel emission. The interfacial potential barrier plays a crucial role in determining the carrier injection.     

Optimum design of dome contour for filament-wound composite pressure vessels based on a shape factor

Filament-wound composite pressure vessels are an important type of high-pressure container that is widely applied in the commercial and aerospace industries. This study investigates the optimum design of dome contours for filament-wound composite pressure vessels, subjected to geometrical limitations, winding condition, and the Tsai–Wu failure criterion and maximizing shape factor, the feasible direction method being employed. An actual design example, presented by Fukunaga et al. [19], is adopted to study the optimum dome contour using the present method. Results reveal that the dome contours using the present method, Fukunaga et al.’s method and the netting method can be approximated using elliptic curves, and that the depth is the major parameter for optimizing the design of dome contour, and the dome, designed using the present method has stronger structure and greater internal volume than those designed using other approaches. Results reveal that the present method is usable for the optimum design of dome contours for filament-wound composite pressure vessels.     

Preparation and properties of aramids based on naphthalenedicarboxylic acid and their molecular composites with amorphous nylon

Two naphthalene-aromatic polyamides were prepared from 2,6-naphthalenedicarboxylic acid and various aromatic diamines by a modified Higashi phosphorylation reaction. The first polymer, poly(4,4′-diaminobenzanilide-2,6-naphthalamide)^** (DBNA), was synthesized by the reaction of 2,6-naphthalenedicarboxylic acid with 4,4′-diaminobenzanilide. The second polymer, 50/50 copoly(1,4-phenylene/1,4-bis(4′-phenoxy)benzene-2,6-naphthalamide)^*** (PBNA), is a copolymer synthesized using an equimolar ratio of 1,4-phenylene diamine and 1,4-bis(4′-aminophenoxy)benzene. These two polymers have inherent viscosities of 4.17 and 2.32 dL g^-1, respectively, and dissolve in N-methyl-2-pyrrolidone (NMP)containing LiCl. Highstrength films were obtained by casting from these polymer solutions. Blends of DBNA/amorphous nylon and of PBNA/amorphous nylon were prepared by rapidly precipitating the ternary NMP solution into deionized water, and hot-pressing to films at 185°C. The compatibility, morphology, and mechanical properties were investigated by dynamic mechanical analysis (DMA), scanning electron microscopy (SEM), and tensile tests. The results revealed that both DBNA and PBNA were partially compatible with amorphous nylon. DBNA formed microfibrils in the amorphous nylon matrix, and its mechanical properties, tensile strength and modulus, improved with increasing DBNA content. PBNA had no reinforcing effect, perhaps because it did not form microfibrils in the amorphous nylon matrix.