Viscosity and die swell of acrylonitrile-butadiene-styrene filled with glass beads and glass fibers

Shear viscosity and die swell ratio of acrylonitrile-butadiene-styrene filled with glass beads and glass fibers were measured. The relative viscosity of the composites increased with filler content, but decreased with shear rate. At low shear rates, fiber filled systems had higher relative viscosities than bead filled systems. At high shear rates, the opposite was observed. The die swell ratio of the unfilled material increased linearly with the logarithm of the shear rate. Systems highly filled with glass beads or fibers showed a maximum in the die swell ratio at medium shear rates. The magnitude of the maximum in the die swell ratio increased with the filler content and the die length, up to a certain length, in a series of dies that had the same radius. The presence of a maximum in the die swell ratio of the filled melts is explained by an order-disorder phenomenon observed earlier by Wu.     

Improving functionality of whole egg powder by the addition of gelatine, lactose, and pullulan

The addition of gelatine (G), lactose (L), pullulan (P), and their mixtures at equal ratios (gelatine + lactose [GL] and gelatin + pullulan [GP]) to whole egg prior to drying was studied. Their effects on the functional properties (emulsion and gelling ability, water holding capacity of gel, foaming, color) and soluble protein content of spray dried egg powder during the 6 mo of storage at 20 °C and 50% relative humidity were investigated. It was demonstrated that the emulsion and foaming stability, water holding capacity of gel, and color change were significantly affected by the storage time, whereas storage time did not affect the strength of gel texture prepared by egg powders. Gelatine and pullulan improved the foaming stability and water holding capacity. Lactose caused a decrease in emulsion and foaming stability values. The maximum color change was observed for the plain egg powder, showing that mixing whole egg with carbohydrate- and/or protein-based additives before the drying process preserved the color of egg powder. Adding carbohydrate and/or protein caused significant changes in functional properties of egg powder.     

Prototypes for building applications based on thermoplastic composites containing mixed waste plastics

Automotive shredder residue (ASR) and a complex residue obtained as a by‐product in the tertiary recycling of nylon‐6 fibers from used carpets were evaluated as potential additives in thermoplastic composites to be used for building applications. Prototype blocks were prepared by the “intrusion” process using various ratios of the waste streams and low‐density polyethylene (LDPE) in the absence of compatibilizers. Hence, product morphologies and corresponding properties were largely controlled through processing. They were evaluated for their short‐term and longterm mechanical properties, flammability, thermal conductivity, and heavy‐metal and total organic carbon leaching characteristics. Encapsulation of the waste feedstock by LDPE during molding in a single‐screw extruder significantly reduced the leachable content. In an effort to further reduce the leachable content, the mixtures were processed in two stages by precompounding in adevolatilizing twin‐screw extruder prior to molding. In comparison to the as‐received wastes, improved homogenization decreased the leachable heavy‐metal content by at least 98%. The carpet residue feedstock consisting of polypropylene, styrene‐butadiene rubber and calcium carbonate appears to be an attractive low‐cost, high‐volume material with consistent properties and could be used as filler in thermoplastic composites. Comparison of their performance characteristics suggested that the carpet residue composites would be favored versus ASR composites as replacement of the wood thermal barrier components in a novel steel‐based stud assembly.     

Enhanced adsorption of Acid Red 88 by an excellent adsorbent prepared from alunite

BACKGROUND: Calcination significantly increased the adsorption performance of alunite for Acid Red 88. RESULTS: The adsorption properties of calcined alunite for Acid Red 88 were investigated. pH, adsorbent dosage, contact time and ionic strength were found to influence the adsorption. Temperature did not significantly affect the process. Kinetic data obey a pseudo‐second‐order model, while intraparticle diffusion is not the only rate‐limiting step. The Langmuir isotherm well described the equilibrium data. The monolayer adsorption capacity of calcined alunite was found to be 832.81 mg g^?1. It was successfully used for the removal of dye in continuous mode at a flow rate of 4.0 mL min^?1. Co‐anions affected the adsorption capacity of calcined alunite but the presence of other organic compounds in the same medium did not significantly change the adsorption performance. Reusability studies showed that the calcined alunite can be reused four times. Electrostatic interaction, ion‐exchange and complexation were found to be effective mechanisms for the adsorption of Acid Red 88 by calcined alunite. CONCLUSION: This study demonstrated that calcined alunite has excellent adsorption performance and might be a very good adsorbent for Acid Red 88 as an abundant, economical and practical material. © 2012 Society of Chemical Industry     

Polyamide 66 binary and ternary nanocomposites: Mechanical and morphological properties

Polyamide 66 (PA 66)/impact modifier blends and polyamide/organoclay binary and PA 66/organoclay/impact modifier ternary nanocomposites were prepared by the melt‐compounding method, and the effects of the mixing sequences on the morphology and mechanical and flow properties were investigated. Lotader AX8840 and Lotader AX8900 were used as impact modifiers. The concentrations of the impact modifiers and the organoclay (Cloisite 25A) were maintained at 2 and 5 wt %, respectively. Both the binary and ternary nanocomposites displayed high tensile strength and Young's modulus values compared to the PA 66/impact modifier blends. Decreases occurred in the strength and stiffness of the binary nanocomposites upon incorporation of the elastomeric materials into the polymeric matrix. In general, the mixing sequence in which all three ingredients were added simultaneously and extruded twice (the All‐S mixing sequence) exhibited the most enhanced mechanical properties in comparison with the mixing sequences in which two of the components were extruded in the first extrusion step and the third ingredient was added in the second extrusion step. The mechanical test results were in accordance with the organoclay dispersion. The impact strength was highly affected by the elastomeric domain sizes, interdomain distances, interfacial interactions, and organoclay delamination. The smallest elastomeric domain size was obtained for the All‐S mixing sequence, whereas the elastomeric domain sizes of the other mixing sequences were quite close to each other. Drastic variations were not observed between the melt viscosities of the ternary nanocomposites prepared with different mixing sequences. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Characteristics of impact modified polystyrene/organoclay nanocomposites

The poor impact resistance of Polystyrene (PS) was enhanced by the addition of elastomeric material, SEBS‐g‐MA. To prevent the reduction in strength and stiffness, organoclay Cloisite® 25A was used as filler and introduced into the matrix by a corotating twin screw extruder. Throughout the study, the clay content was kept at 2 wt%, whereas the content of SEBS‐g‐MA was varied between 5 and 40 wt%. It was found that Cloisite® 25A displays well dispersion in the ternary nanocomposites and the degree of dispersion increases with the elastomer content. The elastomeric phase has a greater viscosity than pure PS. Thus, as expected, at low elastomer contents, it forms the dispersed phase in the matrix as droplets. Transmission electron microscopy results show that the clay layers reside at the interphase between PS and elastomer and also inside the elastomeric phase. Owing to the location of the clay particles, the average elastomer domain size in ternary nanocomposites are found to be greater than that in the relative binary blends of PS‐(SEBS‐g‐MA). Moreover, with the organoclay addition, phase inversion point shifts to lower elastomer contents. The mechanical test results showed that the nanocomposites containing 15 and 20 wt% SEBS‐g‐MA have the optimum average domain size that results in high‐impact strength values without deteriorating the tensile properties. POLYM. COMPOS., 31:1853–1861, 2010. © 2010 Society of Plastics Engineers.     

Effects of mixing protocols on impact modified poly(lactic acid) layered silicate nanocomposites

Poly(lactic acid)/2 wt % organomodified montmorillonite (PLA/OMMT) was toughened by an ethylene‐methyl acrylate‐glycidyl methacrylate (E‐MA‐GMA) rubber. The ternary nanocomposites were prepared by melt compounding in a twin screw extruder using four different addition protocols of the components of the nanocomposite and varying the rubber content in the range of 5–20 wt %. It was found that both clay dispersion and morphology were influenced by the blending method as detected by X‐ray diffraction (XRD) and observed by TEM and scanning electron microscopy (SEM). The XRD results, which were also confirmed by TEM observations, demonstrated that the OMMT dispersed better in PLA than in E‐MA‐GMA. All formulations exhibited intercalated/partially exfoliated structure with the best clay dispersion achieved when the clay was first mixed with PLA before the rubber was added. According to SEM, the blends were immiscible and exhibited fine dispersion of the rubber in the PLA with differences in the mean particle sizes that depended on the addition order. Balanced stiffness‐toughness was observed at 10 wt % rubber content in the compounds without significant sacrifice of the strength. High impact toughness was attained when PLA was first mixed with the clay before the rubber was added, and the highest tensile toughness was obtained when PLA was first compounded with the rubber, and then clay was incorporated into the mixture. Thermal characterization by DSC confirmed the immiscibility of the blends, but in general, the thermal parameters and the degree of crystallinity of the PLA were not affected by the preparation procedure. Both the clay and the rubber decreased the crystallization temperature of the PLA by acting as nucleating agents. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41518.     

Moisture Sorption Isotherms and Storage Stability of Spray-Dried Yogurt Powder

Moisture adsorption isotherms of spray-dried yogurt powder were determined at 10, 25, and 40°C using the standard, static-gravimetric method. Experimental data were fitted to five mathematical models (Guggenheim-Anderson-de Boer [GAB], Brunauer-Emmett-Teller [BET], Halsey, modified Oswin, and modified Henderson). A nonlinear regression analysis method was used to evaluate the constants of the sorption equations. The shelf-life of yogurt powder was predicted based on the relationship between permeability coefficient of the packaging material and moisture adsorbed by the powder determined by the GAB equation. Furthermore, the storage stability of spray-dried yogurt powder in terms of quality parameters including moisture content, water activity, color change, and thiobarbituric acid (TBA) value was studied in aluminum laminated polyethylene (ALPE) pouches under storage conditions of 25°C and 50% relative humidity (RH).     

Viscoelastic characteristics of chain extended/branched and linear polyethylene terephthalate resins

Two chemically modified chain extended/branched polyethylene terephthalate (PET) resins and one unmodified resin, considered to be linear, were characterized in terms of their melt flow, die swell, and viscoelastic properties. The three resins had reportedly similar nominal intrinsic viscosities but exhibited different viscoelastic behavior. The modified resins had lower melt flow index, higher die swell, higher complex viscosity and higher storage modulus than the unmodified one. The Cole–Cole plots of the resins were independent of temperature, and the data for modified resins formed a group that lay below the data group for the unmodified PET. The distribution of relaxation times was determined. The modified resins had higher relaxation strength, G_i, especially at high relaxation times, λ_i. The mean relaxation times of the chain extended/branched resins were approximately an order of magnitude higher than that of the unmodified resin, implying pronounced elastic character. The modified resins had better foaming characteristics in extrusion foam processing than the unmodified one owing to their elastic nature. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1371–1377, 2000