Design and performance evaluation of multilayer packaging films for blister packaging applications

Five multilayer packaging film structures consisting of amorphous poly(ethylene terephthalate) (APET), low‐density polyethylene (LDPE), polypropylene (PP), and acrylonitrile/methyl acrylate copolymer (Barex) films [i.e., APET/polyethylene (PE), APET/PP, APET/PE + UV inhibitor, APET/PP/PE, and APET/Barex/PP] for blister packaging applications were designed and produced. Blister containers with APET/PE and APET/Barex/PP structures were prepared, and their optical, mechanical, barrier (O₂, CO₂, and H₂O), physical, and product/package compatibility performance properties were evaluated. Package/product compatibility with simulants (soy sauce and sunscreen skin cream) at 37.8°C was evaluated for 3, 7, 14, and 28 days in the multilayer films and the blister containers. APET/Barex/PP film showed significantly better O₂ and CO₂ barrier performance than the other four film structures. The UV inhibitor had no significant effect on the barrier properties in the APET/PE film structure. All of the film structures showed high enough elastic storage modulus values to be applied to blister packaging in a broad range of temperatures between ?45 and 80°C. The glass‐transition temperature of APET, which was responsible for the elastic modulus of the multilayer structure, decreased after the samples were exposed to the skin cream. This decrease may have been due to the sorption of the skin cream's active ingredients, such as ethylhexyl methoxycinnamate. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of the silane modification of clay on the tensile properties of nylon 6/clay nanocomposites

A commercially available organomodified clay, Cloisite 25A, was modified with 3‐aminopropyltriethoxysilane, 3‐(glycidoxypropyl)trimethoxysilane, and 3‐isocyanate propyltriethoxysilane to enhance its interaction with the nylon 6 matrix. Composites made of nylon 6 and clays modified with the different silane compounds were prepared by melt mixing with a twin‐screw extruder. The dispersion and degree of exfoliation of the organomodified clays were evaluated from X‐ray diffraction patterns and transmission electron microscopy images of the corresponding composites. The tensile properties of the composites were measured, and their enhancement was attributed to the work of adhesion and interfacial tension of the composites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of Al and Mg Contents on Wettability and Reactivity of Molten Zn–Al–Mg Alloys on Steel Sheets Covered with MnO and SiO<Subscript>2</Subscript> Layers

The reactive wetting behaviors of molten Zn–Al–Mg alloys on MnO- and amorphous (a-) SiO₂-covered steel sheets were investigated by the sessile drop method, as a function of the Al and Mg contents in the alloys. The sessile drop tests were carried out at 460 °C and the variation in the contact angles (θ_c) of alloys containing 0.2–2.5 wt% Al and 0–3.0 wt% Mg was monitored for 20 s. For all the alloys, the MnO-covered steel substrate exhibited reactive wetting whereas the a-SiO₂-covered steel exhibited nonreactive, nonwetting (θ_c?>?90°) behavior. The MnO layer was rapidly removed by Al and Mg contained in the alloys. The wetting of the MnO-covered steel sheet significantly improved upon increasing the Mg content but decreased upon increasing the Al content, indicating that the surface tension of the alloy droplet is the main factor controlling its wettability. Although the reactions of Al and Mg in molten alloys with the a-SiO₂ layer were found to be sluggish, the wettability of Zn–Al–Mg alloys on the a-SiO₂ layer improved upon increasing the Al and Mg contents. These results suggest that the wetting of advanced high-strength steel sheets, the surface oxide layer of which consists of a mixture of MnO and SiO₂, with Zn–Al–Mg alloys could be most effectively improved by increasing the Mg content of the alloys.     

Laser-Assisted Growth of Superconducting MgB2 Films in an In Situ Annealing Process Using a Stoichiometric Target

A superconducting MgB₂ film with a superconducting transition temperature of ∼36 K was successfully prepared on an MgO substrate by pulsed-laser ablation from a stoichiometric MgB₂ target. A multilayer deposition process involving interposed Mg-rich layers was performed at 200°C by controlling the laser energy density in order to maintain the correct stoichiometry, and followed by an in situ annealing process at temperature ranging from 700° to 900°C. It was found that smooth, fine-grained films with superconducting transition temperatures of 24–36 K could be obtained from in situ annealing of the as-deposited multilayer at 900°C without excess Mg addition.     

Excitation-dependent energy transfer and color tunability in Dy3+/Eu3+ co-doped multi-component borophosphate glasses

Using the melt-quench technique, potassium zinc borophosphate (KZnBP) glasses incorporated with Dy³⁺, Eu³⁺, and Dy³⁺/Eu³⁺ ions individually and combinedly were prepared, and their photoluminescence (PL)-related features were investigated. The KZnBP glass containing an optimized content of Dy³⁺ (0.5 mol%) is co-doped with Eu³⁺ in various contents, and the energy transfer (ET) process between them was studied at λ_exci = 349, 364, 387 (Dy³⁺), and 394 nm (Eu³⁺). The Dy³⁺/Eu³⁺ co-doped system, when excited with Dy³⁺ excitations has resulted in a significant decrease in the intensity of Dy³⁺ peaks observed at 480 nm (⁴F_9/2→⁶H_15/2, blue) and 574 nm (⁴F_9/2→⁶H_13/2, yellow), with simultaneous enhancement of the intensity of Eu³⁺ peaks at 591 nm (⁵D₀→⁷F₁, orange) and 617 nm (⁵D₀→⁷F₂, red). This trend is due to the efficient energy transfer from Dy³⁺ to Eu³⁺, indicating that Eu³⁺ ions were sensitized by Dy³⁺ ions. Dexter's theory and the Inokuti–Hirayama (I–H) model revealed that the dipole–dipole interaction is accountable for the energy transfer from Dy³⁺ to Eu³⁺ through energy-transfer channels [⁴F_9/2(Dy³⁺)+⁷F_1,2(Eu³⁺)→⁶H_15/2(Dy³⁺)+⁵D₂(Eu³⁺)] and [⁴F_9/2(Dy³⁺)+⁷F₀(Eu³⁺)→⁶H_13/2(Dy³⁺)+⁵D₀(Eu³⁺)]. The color coordinates of the Dy³⁺/Eu³⁺ co-doped glasses under various excitations fall within the white light emission spectrum, indicating their potential application in warm white LEDs.     

Synthesis and properties of new electroluminescent polymers possessing both hole and electron-transporting units in the main chain

New EL polymers possessing both hole and electron-transporting units in the main chain are synthesized. The polymer prepared by palladium catalyzed Heck reaction of 10 and 15 show a large weight average molecular weight (M_w) (25,000) and small polydispersity index (PDI) (1.2). The oligomers synthesized by Wittig condensation have M_w of 4000 and PDI of 1.8. All the polymer and oligomers synthesized exhibit remarkable thermal stability with high decomposition temperature and high T_g as determined by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) under nitrogen atmosphere. The EL emission maximum peaks of the materials prepared are in the range of 535-560 nm corresponding to green-yellowish-green. Among the three electron-transporting moieties, the 1,3,4-oxadiazole unit shows the best electron injection and transporting property.     

Preparation of sulfonated novel poly(bis[4‐(3‐aminophenoxy) phenyl]sulfone pyromellite)imide derivatives by heterogeneous sulfonation

Sulfonated poly(bis[4‐(3‐aminophenoxy)phenyl]sulfone pyromellite)imide derivatives with various ion‐exchange capacities were prepared by heterogeneous sulfonation with chlorosulfonic acid. The effects of sulfonating agent concentration, reaction temperature, and reaction time were investigated. The mechanical and thermal properties, contact angle, change of polydispersity, and solubility were calculated for studying change of their properties. The reactions were effective, when the temperature is <10 °C and the concentration of chlorosulfonic acid is between 0.05 and 0.1 M. The value of ion‐exchange capacity was increased with reaction time, reaction temperature, and concentration of sulfonating reagent. Thermal and mechanical properties were nearly unchanged according to the degree of sulfonation, but the hydrophilicity indirectly measuring contact angle was increased with increasing the value of ion‐exchange capacity. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1881–1887, 2002     

Effect of DMDBS (3 : 2, 4‐bis(3,4‐dimethyldibenzylidene) sorbitol) and NA11 (sodium 2,2′‐methylene‐bis(4,6‐di‐tertbutylphenyl)‐phosphate) on electret properties of polypropylene filaments

Polypropylene (PP) composite filaments containing two different nucleating agents—DMDBS (3 : 2, 4‐bis(3,4‐dimethyldibenzylidene) sorbitol) and NA11 (sodium 2,2′‐methylene‐bis(4,6‐di‐tertbutylphenyl)‐phosphate) were melt spun to modify polymer electrostatic charging characteristics. Sample filaments were charged with a corona instrument and their surface potentials were measured. Initial surface potential as well as potential stability was monitored through an accelerated decay procedure. NA11 was found to be more efficient as an electret additive leading to a 50% increase in charge stability. Filaments with DMDBS exhibited a faster decay. Charging at elevated temperatures resulted in enhanced charge density and stability for both additives. The fiber microstructure was examined by Wide Angle X‐ray Diffraction and Differential Scanning Calorimetry. Rather than reducing the crystal sizes, X‐Ray diffractograms suggest that the crystal size increases with the addition of nucleating agents, while the degree of crystallinity appears to remain unaltered. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2068–2075, 2013     

Deformation kinetics of polypropylene hollow fibers in a continuous drawing process

Effects of isothermal drawing conditions on the deformation kinetics and dimensional change of polypropylene (PP) hollow fibers in a continuous drawing process were investigated. The deformation behavior of solid PP polymers during stretching between two rolls in the isothermal bath was analyzed by a simple model describing the continuous drawing process with a constitutive relation that can express a true (stress–strain–strain rate) surface of solid semicrystalline polymers. Necking profiles during drawing can be calculated from this model without any special assumption for neck criterion, and the calculated results predict that the localization of deformation is promoted with the increase of applied draw ratios. It is also found that at 20°C, the neck is observed apparently both from the calculated and experimental results, and the strain‐rate sensitivity parameter is considered to be a critical factor that determines the intensity of the neck geometry. The calculated drawing forces are shown to increase with increasing the applied draw ratio and decreasing the drawing temperature, and these trends were verified by experimental results. The hollowness, defined as the ratio of inner to total cross‐sectional area, increases as it is drawn at 30°C, but decreases as drawn above this temperature compared with that of the undrawn fiber. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1836–1845, 1999