Intimate Blend Research Articles

Analysis of physio-mechanical properties of pineapple leaf fiber

The present research demonstrated that different fiber intimate blends allow the broader use of pineapple leaf fiber for the textile and clothing industries. This fiber is obtained from the leaves of pineapple plants by extraction, carried out to separate the cambium and fiber using a decorticator Machine. The physic-mechanical properties such as bundle strength, whiteness, lustre, linear density, breaking load, breaking extension tenacity, textile modulus were determined as per standard method using different testing machine. There is correlation between length, width and thickness where, if the length is higher than width and thickness also higher. Pineapple (PALF) has tremendous mechanical properties and can be applied in making eco-friendly textile goods. Density of PALF is similar to other natural fibers while Textile modulus is very high, and tensile strength is highest among the related natural fibers. These properties are suitable for its application so this pineapple fibers by blending and mixing with other natural fibers and can be produce various types of cloths.

Mixed substituent ether‐containing polyphosphazene/poly(bis‐phenoxyphosphazene) blends as membranes for CO2 separation from N2

AbstractPolyphosphazenes gain much of their physical and chemical properties from the substituents attached to the phosphorus atoms in the backbone. Poly(phosphazenes) that have short‐chain polyether containing substituents, such as, 2‐(2‐methoxyethoxy)ethanol, have high CO2 permeability and selectivity over N2 as well as resistance to degradation under humidification at 60°C. However, the principal shortcomings of this polymer are the poor mechanical and surface characteristics. Blending of an example of this polyphosphazene (MEEP‐80) with poly(bis‐phenoxyphosphazene) (PPOP) has yielded more durable materials that have a non‐adhesive surface. In this work, the blended polymer membranes were found to have increased CO2 permeability with higher selectivity over N2. Thermal analysis and the application of transport models support a structure of the blends that is not either an intimate blend or phase separated bulk structure, but one where PPOP domains retain their crystallinity and are dispersed within an amorphous MEEP‐80 phase.

Photocathodic hydrogen evolution from catalysed nanoparticle films prepared from stable aqueous dispersions of P3HT and PCBM

Photo-assisted hydrogen evolution is achieved on photocathodes comprising of nanoparticles of poly(3-hexylthiophene) (npP3HT) and nanoparticles of phenyl-C61-butyric acid methyl ester (npPCBM) onto which ultra-low loadings of Pt nanoparticles are deposited. The nanoparticles, npP3HT and npPCBM, are prepared individually via miniemulsion using surfactants of opposite head group polarity. Aqueous dispersions of npP3HT:npPCBM, devoid of organic solvent, are cast conformally onto ITO-coated glass to yield water-insoluble bulk-heterojunction films. Pt (1 μg/cm2) catalyst is deposited photoelectrochemically onto ITO/npP3HT:npPCBM photocathodes and found to nucleate preferentially on PCBM nanoparticles. ITO/npP3HT:npPCBM/Pt photocathodes produce 65 μA/cm2 photocurrent under 100 mW/cm2 of visible light at 0.0 VSHE and liberate H2 gas. The photocurrents observed for electrodes prepared using npP3HT:npPCBM are twice as large, and the onset potential is ∼0.4 V more positive than analogous photocathodes cast from nanoparticles each comprising an intimate blend of P3HT and PCBM. These are encouraging results for large scale synthesis of organic photoelectrochemical devices, given the simplicity of the photoelectrode, i.e., prepared from aqueous solutions and devoid of vacuum-deposited films such as charge transport layers and protective films.

GEORG HEYM, DIECINUEVE VENTANAS A SU POESÍA

Estas líneas proponen un recorrido por la producción poética de Georg Heym, figura iniciática del Expresionismo alemán. El objeto de la selección realizada es mostrar la diversidad de fuentes que nutren al autor, y que someten su obra a un delicado pulso entre herencia e innovación. La cuidada métrica resiste la presión de una temática rebosante de obsesión y presagio. Una cultura potente y suicida, la de la Alemania de anteguerras, desborda por boca del autor en una alocución donde creación y destrucción conviven en misterioso e íntimo connubio.

PROPERTIES OF HYDROENTANGLED NONWOVEN FABRICS MADE WITH GREIGE COTTON LINT, SELECTED MANMADE STAPLE FIBERS, AND THEIR INTIMATE BLENDS WITH THE LINT IN DIFFERENT BLEND RATIOS

For the first time ever, a preliminary study has been conducted to assess the effects of intimate blending of greige (raw) cotton and certain commonly used manmade fibers on properties of the resulting nonwoven fabrics made with different blend ratios. Implementing the hydroentanglement system of making nonwoven fabrics, twenty one (21) fabrics were made separately, using the selected pre-cleaned Upland greige cotton lint, polyester, polypropylene, Tencel, viscose rayon, bleached cotton, and intimate blends of the cotton lint with the other fibers in 80:20, 50:50 and 20:80 blend ratios. With the exception of 100% polypropylene fiber and its 80:20 intimate blends with cotton, all other fibers and their various blends with the greige cotton were processed on the mill-like equipment available at the Center. The fabrics were not scoured and/or bleached to totally remove the greige cotton’s native (hydrophobic) waxes. The results have shown that the improvement of desirable features of absorbency and whiteness of optimally blended greige cotton-based nonwoven fabrics could be significant incentives for rethinking cotton’s use in nonwovens, especially in the fem-hygienic products where the consumer’s choices of good absorbency, whiteness and comfort indeed matter!

Non-Bleaching Heather Method for Improved Whiteness of Greige Cotton

In accordance with the color space theory known as additive light mixing, the presence of dispersed blue-dyed fiber reduced the overall yellowness of a blended greige fiber and they were perceived as “whiter”. Various intimate blends of blue-dyed cotton fiber in greige cotton fiber were analyzed for color properties using a L*a*b* color space chromameter and a Ultraviolet-Visible (UV-Vis) spectrophotometer. A design of experiments (DOE) matrix approach provided a statistically-based mathematical means to predict the color properties of the intimate blends. The predictive accuracy of the mathematical model was confirmed in a follow-up experiment, and the blend resulting in the lowest yellowness and highest whiteness was determined. For fiber end uses which are too cost sensitive to support comprehensive wet chemical treatment of all of the fiber, such as nonwovens, intimate blending with low amounts of dyed fiber could produce visible effects at lower cost.

A Performant Dry Reforming Catalytic System Elaborated from the Reductive Decomposition of BaNi2V2O8

AbstractThe reductive decomposition of BaNi2V2O8 leads to a Ni‐supported catalyst composed by an intimate blend of Ba3(VO4)2/Ni/BaV10O15. High activity for the Dry Reforming of Methane (DRM) is attained with 85 % conversion for CH4 and CO2, as well as a very good stability in time and a high selectivity with H2/CO=0.9 and negligible carbon deposition. A rich redox and optimal oxide‐metal interactions provide a unique and promising catalytic system.

Conjugated Polyelectrolyte Blends for Electrochromic and Electrochemical Transistor Devices

Two self-doped conjugated polyelectrolytes, having semiconducting and metallic behaviors, respectively, have been blended from aqueous solutions in order to produce materials with enhanced optical and electrical properties. The intimate blend of two anionic conjugated polyelectrolytes combine the electrical and optical properties of these, and can be tuned by blend stoichiometry. In situ conductance measurements have been done during doping of the blends, while UV–vis and EPR spectroelectrochemistry allowed the study of the nature of the involved redox species. We have constructed an accumulation/depletion mode organic electrochemical transistor whose characteristics can be tuned by balancing the stoichiometry of the active material.

Nanohybrid MoS2-PANI-CdS photocatalyst for hydrogen evolution from water

A ternary nanohybrid material, MoS2-PANI(polyaniline)-CdS, exhibits enhanced photocatalytic activity for hydrogen generation from water compared to single phase CdS, MoS2-CdS and PANI-CdS composites. The photocatalytic activity increases further when palladium is used as co-catalyst. The modified CdS composite catalyst is found to be stable for repeated cycles of photocatalytic experiments. Increased visible light absorption is seen when CdS is modified with PANI and MoS2 having a layered structure. Detailed characterization suggests that CdS, PANI and MoS2 exist as an intimate blend in the composite. Time resolved fluorescence studies show an increased lifetime for the photogenerated charge carriers in MoS2-PANI-CdS composite. Photocurrent measurements show relatively higher current output for the MoS2-PANI-CdS sample compared to CdS and other binary composites. The increased photocatalytic activity of the modified CdS catalyst is attributed to the increased visible light absorption, increased photoresponse and increased lifetime of the photogenerated charge carriers promoted by both PANI and MoS2. In the presence of Pd co-catalyst, interfacial transfer of electrons from the catalyst to Pd occurs, which enhances the separation of charge carriers and provides active sites for hydrogen evolution. Present study provides insights for improving the photocatalytic activity of CdS photocatalyst.

Bulk heterojunction organic solar cells fabricated by oblique angle deposition.

Bulk heterojunction organic solar cells based on small molecules are often fabricated by the co-deposition of donor and accepter materials on substrates placed horizontally. An intimate blend of donor and acceptor molecules is the common product in as-prepared samples. Using metal phthalocyanine as the donor and fullerene as the acceptor, we tilt the substrate to deposit the active layer. Both short circuit current density and open circuit voltage increase obviously in bulk heterojunction organic solar cells fabricated by oblique angle deposition. Analysis of the active layer reveals that phase segregation occurs in obliquely deposited bulk heterojunction layers. The mechanism of phase segregation is discussed. A change in the stacking style of fullerene molecules on metal phthalocyanine grains is proposed on the tilted substrate. This result provides a simple method to form phase segregation in bulk heterojunction layers.

A High-Performance p-Doped Conducting Polymer Blend Based on Sulfonated Polyalkoxythiophene and Poly(4-hydroxystyrene)

Understanding the fundamental mechanisms of electrical degradation or instability in organic semiconductor devices is a key step toward their rational design for higher performance and more demanding applications. Here we report the successful suppression of the conductivity fade phenomenon that occurs in doped conducting polymers when they are stress-biased with a large electric field or current density. While poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDT:PSSH) shows a relatively low threshold to conductivity fading, the recently developed sulfonated poly{thiophene-3-[2-(2-methoxyethoxy)ethoxy]-2,5-diyl}:poly(4-hydroxystyrene) (S-P3MEET:PHOST), which is an intimate blend of S-P3MEET and PHOST, is far more resilient. In situ UV–vis, Raman, and Fourier-transform infrared spectroscopies reveal that the doping level across S-P3MEET:PHOST films remains remarkably stable when they are driven at high dc biases. Spectroelectrochemical Raman measurements suggest that both S-P3MEET and S-P3MEET:PHOST are also less susceptible to electrochemical dedoping than PEDT:PSSH. Comparison of the conductivity fading characteristics of S-P3MEET in the presence or absence of PHOST, however, reveals a large matrix effect. We obtained evidence that the enhanced electrical stability of S-P3MEET:PHOST results from its inherent ultralow ionic conductivity, further suppressed by a serendipitous scavenging of excess sulfonic acid protons on S-P3MEET through a solid-state esterification reaction with PHOST during annealing. The shutdown of the ionic conductivity cuts off the coupled ion transfer processes needed to cause a doping level shift in the film. This affords a practical means of suppressing the electrically induced doping level instability in doped conducting polymer systems.

Multi-fiber needle-punched nonwoven composites: Effects of heat treatment on sound absorption performance

Nonwovens have been increasingly used in car interiors for noise reduction. Most of these nonwovens are subjected to thermal treatments to give the nonwovens their final three-dimensional forms. Therefore, it became crucial to investigate the effects of thermal treatment on sound absorption characteristics of nonwovens. In this study, the effects of the material and treatment parameters on airflow resistivity and normal-incidence sound absorption coefficient of thermally treated three-layered nonwoven composites have been studied. The material parameters included fiber size and porosity. The treatment factors included the temperature and duration. The thermally treated three-layered nonwoven composites are classified into three types based on the material content and fiber blend. Sandwich structures consisting of polylactide/hemp/polylactide and polypropylene/glassfiber/polypropylene layers were called LHL and PGP, respectively. The sample which consisted of three layers of an intimate blend of polypropylene-glassfiber was named as PGI. Both temperature and duration of thermal treatment have been found to affect air flow resistivity and sound absorption. An increase in air flow resistivity and a decrease in sound absorption have been detected with heat treatment. A similarity has been observed between the thermal behaviors of PGP and PGI, which included the same thermoplastic polymer fiber. Variation in air flow resistivity of sandwich structure nonwoven composites increased with the increase in temperature, which was not observed in the intimate blend ones. The air flow resistivity of heat-treated nonwovens followed a steeper trend compared to unheated nonwovens per change in material parameters. In terms of treatment parameters, the difference between the thermal treatment and the melting point of the thermoplastics constituent of the nonwoven composite was found to be a significant factor on sound absorption. This effect of treatment temperature on sound absorption changed with treatment duration. The sound absorptive characteristic of the nonwoven composites in terms of sound frequency underwent a change with thermal treatment due to the structural changes with exposure to high temperature.

Study of structural and thermal properties of electron beam irradiated polymethylmethacrylate/bisphenol‐A‐polycarbonate blends

AbstractPolymethylmethacrylate (PMMA) and bisphenol‐A‐polycarbonate (PC) polymer blends are prepared by solution casting technique using tetrahydrofuran as a solvent. The structural properties of the polymer blends before and after they had been irradiated to electron beam accelerator was investigated by color strength, scanning electron microscopy (SEM), and FTIR spectroscopy. The thermal properties such as TGA and DSC were investigated. The TGA thermograms showed that the thermal stability of the unirradiated polymer blends PMMA/PC increases with increasing the ratios of PC component in the blend. Also, it was found that the presence of PC polymer in the blend affords protection against radiation degradation and improves their thermal stability. The DSC scans show a single Tg intermediate between PMMA and PC indicate the existence of specific interactions between PMMA and PC polymers in the blend. An intimate blends are reflected by substantial shifts in the frequencies of the PMMA and PC CO vibration obtained by FTIR. SEM confirms the homogeneity of the blend. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci 125:3184–3190, 2012

Effects of material and treatment parameters on noise‐control performance of compressed three‐layered multifiber needle‐punched nonwovens

AbstractThe effects of material and treatment parameters on airflow resistivity and normal‐incidence sound absorption coefficient (NAC) of compressed three‐layer nonwoven composites have been studied. Material parameters included fiber size and porosity, and treatment factors included applied pressure and duration of compression. Fibers used included poly(lactic acid) (PLA), polypropylene (PP), glassfiber, and hemp. Three‐layered nonwoven composites were classified based on material content and fiber blend. LHL and PGP were sandwiched structures consisting of PLA/Hemp/PLA and PP/glassfiber/PP layers, respectively. PGI consisted of three layers of an intimate blend of PP and glassfiber. Statistical models were developed to predict air flow resistivity from material parameters and the change in air flow resistivity from compression parameters. Independent variables in the first model were porosity and fiber size and, in the latter model, were compressibility, pressure, and initial material parameters. An increase in air flow resistivity was found with increased compression. No significant effect of compression duration was detected. Two additional statistical models were developed for the prediction of sound absorption coefficient based on material and treatment parameters. The independent variables of the first model were air flow resistivity, thickness, and frequency, and those of the second model were compressibility, initial thickness, and initial density of the composite, diameter and density of the fiber, compression pressure, and frequency. A decrease in sound absorption coefficient was detected with increasing compression, while no effect of duration was detected. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Effect of intermolecular hydrogen-bonding and terminal substituents on the mesophase behavior of binary mixtures of dissimilarly-substituted benzoic acids

Binary mixtures of two types of 4-substituted benzoic acids, covering the whole composition range, were prepared by melting both components together, stirring to give an intimate blend, and then cooling to room temperature. The mixtures prepared were characterized for their mesophase behavior by differential scanning calorimetry (DSC) and polarized-optical microscopy (POM). The first type of the acid is substituted with a small compact polar group that cover a wide range of polarity. The other type of the acid is 4-alkoxy benzoic acid bearing an alkoxy (OC n H 2 n+1 ) group with varying chain length ( n = 6–16). Binary phase diagrams were constructed whereby all phases observed were identified by POM. The smectic C (SmC) mesophase was observed in all mixtures investigated, while the nematic phase (N) was observed, together with the SmC phase, only in mixtures possessing the acid homologues with n ≤ 12 carbons. Complex formation was also supported by FT-IR spectroscopic measurements.

Separating Ion and Electron Transport: The Bilayer Light-Emitting Electrochemical Cell

The current generation of polymer light-emitting electrochemical cells (LECs) suffers from insufficient stability during operation. One identified culprit is the active material, which comprises an intimate blend between an ion-conducting electrolyte and an electron-transporting conjugated polymer, as it tends to undergo phase separation during long-term operation and the intimate contact between the ion- and electron-transporting components provokes side reactions. To address these stability issues, we present here a bilayer LEC structure in which the electrolyte is spatially separated from the conjugated polymer. We demonstrate that employing this novel device structure, with its clearly separated ion- and electron-transport paths, leads to distinctly improved LEC performance in the form of decreased turn-on time and improved light emission. We also point out that it will allow for the utilization of combinations of active materials having mutually incompatible solubilities.

Organizational stabilities of bulk neat and well‐mixed, blended polymer samples coalesced from their crystalline inclusion compounds formed with cyclodextrins

AbstractCyclodextrins (CDs) are cyclic starches containing α‐1,4‐linked glucose units. Commonly available α‐, β‐, and γ‐CDs have six, seven, and eight glucose units, respectively. They are well known for forming noncovalent inclusion complexes (ICs) with a variety of guest molecules, including many polymers, by threading and inclusion into their relatively hydrophobic interior cavities, which are roughly cylindrical, with diameters of ∼0.5–1.0 nm. Warm water washing of crystalline CD‐ICs containing polymer guests insoluble in water or treatment with amylase enzymes serve to remove the host CDs and result in the coalescence of the guest polymers into solid bulk samples. When guest polymers are coalesced from their CD‐ICs by carefully removing the host CD lattices, they are observed to solidify with structures, morphologies, and even conformations that are distinct from bulk samples made from their solutions and melts. In addition, molecularly mixed, intimate blends can be obtained upon coalescence of two or more normally immiscible polymer guests from their common CD‐ICs. Not only are the organizations and behaviors of bulk polymer samples significantly modified on coalescence from their CD‐ICs, but both are also maintained for significant periods of time even when heated above their Tgs and Tms, where their chains are mobile. Here, we discuss the long‐time, high temperature stabilities of the organizations and properties of bulk polymers coalesced from their crystalline CD‐ICs. While random‐coiling of their initially coalesced, largely extended, separated, and unentangled chains may be relatively rapid, we conclude that the subsequent slow establishment of homogeneous melts or phase‐segregated blends results from the extremely sluggish center‐of‐mass diffusion that must accompany full entanglement of their chains. Apparently, the process of entangling the largely separated and not fully interpenetrating randomly coiled chains initially coalesced from their CD‐ICs is particularly slow, much slower in fact than the center‐of mass diffusion of polymer chains in their fully entangled melts. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1543–1553, 2009

QM/MM: What Have We Learned, Where Are We, and Where Do We Go from Here?

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QM/MM: what have we learned, where are we, and where do we go from here?

This paper briefly reviews the current status of the most popular methods for combined quantum mechanical/molecular mechanical (QM/MM) calculations, including their advantages and disadvantages. There is a special emphasis on very general link-atom methods and various ways to treat the charge near the boundary. Mechanical and electric embedding are contrasted. We consider methods applicable to gas-phase organic chemistry, liquid-phase organic and organometallic chemistry, biochemistry, and solid-state chemistry. Then we review some recent tests of QM/MM methods and summarize what we learn about QM/MM from these studies. We also discuss some available software. Finally, we present a few comments about future directions of research in this exciting area, where we focus on more intimate blends of QM with MM.

Observations of Soiling of Nylon 66 Carpet Fibers

Soiling of nylon 66 carpets was studied to investigate the effect of spin finishes with and without fluorocarbons finishes; and, in addition, the use of a secondary extraction process was examined to determine the effect of removing residual spin finish oils. Two types of residential carpet of intimate blend trilobal fibers with two modification ratios were evaluated: one had fluorcarbons in the spin finish with an additional topical mill-applied fluorocarbon. The second carpet had no fluorocarbons in the spin finish, but had a topical mill-applied fluorocarbon finish so that both carpets had a target of 250 to 300 ppm fluorine. Acetone extraction was used to remove the spin finishes from the carpets. Both carpets with and without extraction were soiled with particulate soil in the laboratory. Visual ratings and color difference measurements indicated more soiling on the carpets that had been extracted. Fluorine analysis showed that fluorcarbons were removed from both carpet types with the acetone extraction. Electron microscopy indicated the deposition of soil in the V-groove of the filaments with the higher modification ratio. Furthermore, fiber surfaces near the face of the carpet exhibited higher levels of soil than surfaces located near the carpet backing.