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The processing conditions were varied during the production of polycarbonate-based composites with the multiwalled carbon nanotubes (MWCNTs) Baytubes® C150 P (Bayer MaterialScience AG, Leverkusen, Germany), by melt mixing with an extruder on a laboratory scale. These included the screw design, rotation speed, throughput, feeding position and MWCNT content. Particular attention was paid to the shortening of the MWCNT length as a function of the conditions mentioned. It was found that there is a correlation between the applied specific mechanical energy (SME) during the melt mixing process and MWCNT dispersion, which was quantified by the agglomerate area ratio of the non-dispersed nanotubes based on optical microscopic analysis. The higher the SME value, the lower this ratio, which indicates better dispersion. Above an SME value of about 0.4 kWh/kg, no further improvement in dispersion was achieved. The MWCNT length, as measured by the quantitative analysis of TEM images of the MWCNTs dissolved from the composites, decreased with the SME value down to values of 44% of the original MWCNT length. At a constant loading of 3 wt.%, the tensile strength and tensile modulus were almost independent of the SME, while the elongation at break and notched impact strength showed an increasing trend. The variation in the feeding position showed that feeding the MWCNTs into a side feeder led to slightly better electrical and mechanical properties for both types of MWCNTs studied (Baytubes® C150 P and Nanocyl™ NC7000 (Nanocyl S.A., Sambreville, Belgium)). However, feeding into the hopper led to better CNT dispersion with Baytubes® C150 P, while this was the case with Nanocyl™ NC7000 when feeding into the side feeder. The screw profile had an influence on the dispersion, the MWCNT length and the electrical resistance, but only to a small extent. Distributive screws led to a greater shortening of the MWCNT length than dispersive screws. By varying the MWCNT content, it was shown that a greater MWCNT shortening occurred at higher loadings. Two-stage masterbatch dilution leads to stronger shortening than composite production with direct MWCNT incorporation. [ABSTRACT FROM AUTHOR]

Innovative melt processing technology is necessary for the production of biodegradable polylactide/graphene nanocomposites. In this paper, we present the aqueous spray coating method to prepare graphene-coated polylactide granules for improving the distribution of small graphene contents in polymer matrix during the melt mixing process. Three types of functionalized graphene nanosheets, including graphene oxide (GO), reduced graphene oxide (RGO) and poly(ethylene glycol)/RGO (PEG/RGO), were investigated in the formations of graphene coatings on polylactide granules and subsequent melt-processed nanocomposites. It is found that RGO nanosheets have good interfacial compatibility to form better coatings on polylactide granules. Melt processing of graphene-coated granules produced polylactide/graphene nanocomposites with higher mechanical strengths. Nanocomposite materials containing 0.1% RGO showed the best improvements of mechanical and thermal properties. As-prepared nanomaterials and nanocomposites were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), ultraviolet-visible spectroscopy (UV-Vis), attenuated total reflectance infrared spectroscopy (ATR-FTIR), tensile, flexural and impact measurements, differential scanning calorimetry (DSC) and integrated thermogravimetric analysis (TGA-DTA). In general, the innovative strategy of aqueous spray coating and melt processing is applicable for manufacturing biodegradable PLA/graphene nanocomposites in the sustainable trend of environmentally friendly development. [ABSTRACT FROM AUTHOR]

The rising concern of environmental issues from the non-degradable conventional polymers is triggering the development of sustainable and renewable polymers. Thermoplastic starch (TPS) has been known to have huge potential to substitute conventional synthetic polymers. A thermoplastic starch was prepared using a non-food bitter cassava starch with isosorbide as plasticizer. To improve the dispersion and interfacial affinity of thermoplastic starch and boost the compatibility between starch and isosorbide, citric acid (CA) was used as an additive. The influence of citric acid to the TPS was then investigated. The result shows that citric acid improved tensile strength from 8.68 MPa to 11.98 MPa. The addition of citric acid at a concentration of 1 – 10 wt % can increase glass transition temperature (Tg) from 48.81°C to 63.89°C and storage modulus at 25°C from 1.20 GPa to 3.47 GPa. Two degradation temperatures (Td) were detected which are Td1onset value was decrease from 83.32°C down to 79.78°C while Td2onset value was decrease from 275.29°C down to 247.17°C and Td2max from 311.12°C to 295.06°C. [ABSTRACT FROM AUTHOR]

Graphene-related materials (GRM) are promising materials to improve mechanical, electrical, and optical polymer properties. Adding multi-wall carbon nanotubes (MWCNT) on GRM nanocomposites promotes synergistic effects on its electrical properties and electromagnetic interference shielding effectiveness (EMI SE). This study focused on evaluating the addition of MWCNT on three different polycarbonate (PC)/acrylonitrile butadiene styrene (ABS)/GRM nanocomposites. These hybrid nanocomposites were prepared by melt mixing using extrusion and injection-mold processes. The morphologies of the nanocomposites were evaluated by field emission gun scanning electron microscopy (FEG-SEM), and their proprieties were characterized by X-ray diffraction (XRD), oscillatory rheological, dielectric spectroscopy, and EMI SE analyses. The electrical behavior of all hybrid nanocomposites was anisotropic due to the injection-molded preparation process. The lateral size, thickness, and production method of the GRM were indicated to be critical factors for the electrical and EMI SE behaviors of these composites. The nanocomposites with GRM2, which had the smallest lateral size and thickness (graphene nanoplatelets), promoted total attenuation levels around 20 dB with 1.5 wt% of MWCNT, matching the EMI SE required for some commercial applications. Graphical Abstract [ABSTRACT FROM AUTHOR]

Biodegradable products are considered as an important solution in reducing the waste generated by the use of synthetic polymers. Thermoplastic starch (TPS) stands out with its success and low cost in the preparation of biodegradable products. In order to improve the low mechanical and physical properties of biodegradable polymeric products, morphology in co-continuous form was chosen as the target of our study as a promising solution. For this purpose, thermoplastic starch samples were prepared by melt processing method using starch and various plasticizers. TPS samples were examined from the perspective of morphological, rheological and thermal properties. Based on the obtained results, suitable TPS was determined that will allow obtaining the co-continuous morphology in the polymer blends to be prepared with polyethylene (PE). Polymer blends were prepared by melt processing method so that the selected TPS sample and PE were in different compositions. TPS/PE polymer blends were examined in terms of mechanical, rheological, morphological and thermal properties, and the most appropriate methods and parameters were determined for the preparation of samples with high TPS composition and co-continuous phase morphology. [ABSTRACT FROM AUTHOR]

Polypropylene (PP) is one of the most versatile polymers widely used in packaging, textiles, automotive, and electrical applications. Melt blending of PP with micro- and/or nano-fillers is a common approach for obtaining specific end-use characteristics and major enhancements of properties. The study aims to develop high-performance composites by filling PP with CaSO4 β-anhydrite II (AII) issued from natural gypsum. The effects of the addition of up to 40 wt.% AII into PP matrix have been deeply evaluated in terms of morphology, mechanical and thermal properties. The PP–AII composites (without any modifier) as produced with internal mixers showed enhanced thermal stability and stiffness. At high filler loadings (40% AII), there was a significant decrease in tensile strength and impact resistance; therefore, custom formulations with special reactive modifiers/compatibilizers (PP functionalized/grafted with maleic anhydride (PP-g-MA) and zinc diacrylate (ZnDA)) were developed. The study revealed that the addition of only 2% ZnDA (able to induce ionomeric character) leads to PP–AII composites characterized by improved kinetics of crystallization, remarkable thermal stability, and enhanced mechanical properties, i.e., high tensile strength, rigidity, and even rise in impact resistance. The formation of Zn ionomers and dynamic ionic crosslinks, finer dispersion of AII microparticles, and better compatibility within the polyolefinic matrix allow us to explain the recorded increase in properties. Interestingly, the PP–AII composites also exhibited significant improvements in the elastic behavior under dynamic mechanical stress and of the heat deflection temperature (HDT), thus paving the way for engineering applications. Larger experimental trials have been conducted to produce the most promising composite materials by reactive extrusion (REx) on twin-screw extruders, while evaluating their performances through various methods of analysis and processing. [ABSTRACT FROM AUTHOR]

Summary: The present study aimed to produce polylactic acid (PLA) and ethyl cellulose (EC) biodegradable film using a single screw extruder and a roller mixer machine. This method resulted in better mixing of the polymers, reducing the possibility of burns and easier control of the film thickness. The mechanical properties measurement showed that tensile strength (TS) decreased by about 37.9%, and elongation at break (EAB) increased about 2.6‐fold by increasing EC to 75%. The increase in EAB indicated the plasticising effect of EC. Since flexibility is essential in shaping a material without fracture, PLA/EC blend films can be a good candidate for packaging. According to DSC results, glass‐transition temperature (Tg) decreased in the blend films, probably due to the increase in the hydrophilicity of the films after EC addition. The water contact angle of pure PLA film was about 83°, whereas it reached 28° in the film containing 75% EC. The water vapour permeability of PLA film was 2.24 × 10−11 g m.s.Pa−1 and PLA reduction to 25% increased the WVP by about two times. Adding EC into the pure PLA film reduced the transparency, indicating the potential of blend film for the packaging of light‐sensitive food products. Besides, EC addition enhanced PLA biodegradability after enzymatic treatment (alcalase) and soil burial. [ABSTRACT FROM AUTHOR]

In this study, silane grafted and moisture cross-linked low density polyethylene nanocomposite foams were prepared by melt mixing and batch foaming process and the effects of silane content, nanoclay content, foaming agent concentration and clay type (clay modified with vinyltriethoxysilane (VTES) and amino-propyltriethoxysilane on foaming efficiency and foam properties were investigated. The morphology and the efficiency of silane modification of modified clay were characterized by series of tests, including X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). The results of Fourier transform infrared and thermogravimetric analysis showed that the silane modifiers were bonded to the surface of nanoclay through both physical and chemical bonds. According to XRD, these modifiers caused characteristic peak of clay to shift to lower angles, and make an increase in basal spacing. Gel content, density, scanning electron microscopy, compression, creep and rheological tests were used to determine the effect of different parameters on properties of cross-linked polyethylene foams. Results indicated that silane content has the significant effect on stress-strain behavior in compression mode. Compression set and creep deformation were affected by cell size and gel content. Furthermore, the rheological properties including complex viscosity, storage and loss modulus of unformed samples increased with the addition of silane and nanoclay content. [ABSTRACT FROM AUTHOR]

In recent years, significant attention has been given to "green" product innovation and related manufacturing processes. This work reports the preparation of few‐layer graphene (FLG) and respective PLA‐based composites by an eco‐friendly, efficient, and cost‐effective approach. FLG was produced in a scaled‐up process, based on the noncovalent functionalization of a micronized graphite with a pyrene derivate (PY), in aqueous solution. The exfoliation degree, morphology, and thermal stability of the exfoliated material were evaluated. Then, the influence of the pristine graphite and FLG on the morphology, crystallinity, thermal and mechanical properties of PLA composites produced by melt mixing is reported for the first time. The composites prepared with the lowest loading of 0.05 wt% demonstrated suitability for further processing for potential applications where product safety is crucial, such as in biomedicine. [ABSTRACT FROM AUTHOR]

In this study, eco-grade thermoplastic polyurethane (TPU), which includes 46% renewable content, was reinforced with date palm seed (DPS). Alkali and silane surface treatments were applied to DPS to increase the compatibility between DPS and TPU matrix. The oil of DPS was removed before treatments and surface functionalities of modified and pristine DPS samples were examined by Fourier transform infrared spectroscopy. Composites were fabricated using melt blending method and injection molding processes. Test samples of composites were characterized using tensile test, hardness test, water absorption study, dynamic mechanical analysis (DMA), melt flow index (MFI) test, thermogravimetric analysis, and scanning electron microscopy (SEM). According to test results, silane treatment led to remarkable improvement for mechanical performance of composites attributed to improvement of compatibility and interface adhesion between DPS and TPU. DMA results implied that higher storage modulus and glass transition temperature were achieved for treated DPS-containing composites compared to pristine DPS filled ones. Thermal stability of flexible segment of TPU increased with the addition of DPS regardless of surface treatment. Additionally, DPS loadings caused significant increase in MFI value of unfilled TPU. Silane-treated DPS-containing composite yielded the lowest water uptake value among samples due to the hydrophobicity of silane layer. Enrichment of interface adhesion of DPS to TPU matrix was confirmed by SEM micrographs of composites. Silane-treated DPS-containing composite displayed higher results among produced composites since the increase in interfacial interactions with TPU was achieved by silane treatment for DPS surface. [ABSTRACT FROM AUTHOR]

The influence of carbon nanotubes (CNTs) purity on the viscosity, thermal properties, impedance characteristics, and conductivity of CNT/low-density polyethylene (LDPE) nanocomposites was investigated. Two grades of CNT of similar aspect ratios but with different levels of carbon purities were investigated. CNTs with 90% ( C N T 90) and 95% ( C N T 95) carbon purity were used. The impedance analysis showed a lower electrical percolation threshold (EPT) of the C N T 90 / LDPE compared to the C N T 95 / LDPE. Also, at the same nanofiller loading, the characteristic frequency ( f c ) of the C N T 90 / LDPE composites was higher than that of the C N T 95 / LDPE composites. For example, at 7 wt% CNT, the f c of the C N T 90 / LDPE and C N T 95 / LDPE composites were 102 and 1.0 Hz, respectively. This finding reveals better dispersion of the C N T 90 compared to the C N T 95 in the LDPE. The better dispersion of CNT90 compared to CNT95 in the LDPE is supported by the processing behavior analysis that showed higher viscosity and mixing torque for the C N T 90 / LDPE composites compared to the C N T 95 / LDPE composites. [ABSTRACT FROM AUTHOR]

The acoustic melt stream velocity field, total force, and trajectory of fluorescent particles in the plasticizing chamber were analyzed using finite element simulation to investigate the acoustic streaming and mixing characteristics in ultrasonic plasticization micro-injection molding (UPMIM). The fluorescence intensity of ultrasonic plasticized samples containing thermoplastic polymer powders and fluorescent particles was used to determine the correlation between UPMIM process parameters and melt mixing characteristics. The results confirm that the acoustic streaming driven mixing occurs in ultrasonic plasticization and could provide similar shear stirring performance as the screw in traditional extrusion/injection molding. It was found that ultrasonic vibrations can cause several melt vortices to develop in the plasticizing chamber, with the melt rotating around the center of the vortex. With increasing ultrasonic amplitude, the melt stream velocity was shown to increase while retaining the trace, which could be altered by modulating other parameters. The fluorescent particles are subjected to a two-order-of-magnitude stronger Stokes drag force than the acoustic radiation force. The average fluorescence intensity was found to be adversely related to the distance from the sonotrodes' end surface, and fluorescence particles were more equally distributed at higher parameter levels. [ABSTRACT FROM AUTHOR]

The influence of polyethylene (PE) molecular structure on multi-walled carbon nanotubes (MWCNT)/PE composites processing behavior and their thermal, rheological and electrical properties were investigated. Two different types of PE of almost the same viscosity were investigated; namely, high-density polyethylene (HDPE) and low-density polyethylene (LDPE). Nanocomposites filled with up to 10 wt.% MWCNT were prepared by the conventional melt-mixing method. The MWCNT exhibited better dispersion in HDPE than in LDPE. The crystallinity of the HDPE marginally increased with the addition of the MWCNT, while no significant influence of the MWCNT on the LDPE crystallinity was observed. The AC electrical conductivity of both the HDPE and LDPE nanocomposites were almost the same. Thus, we concluded that there is no significant effect of the PE structure on the formation of the MWCNT networks. [ABSTRACT FROM AUTHOR]

The investigation of polypropylene (PP)/clay nanocomposites has received considerable scientific and technological attention during the last decades due to their good mechanical and barrier properties. In the present article, the effects of adding Cloisite15A (C15A) nanoclay in polypropylene (PP) were investigated. PP nanocomposites were prepared by a direct melt mixing method. For better dispersion of C15A, 30 wt% of nanoclay masterbatch was first prepared by melt mixing of PP matrix and acrylic acid grafted PP oligomer (PP- g -AA) in a compounder, before being used to produce nanocomposites with 2 and 5 wt% of C15A. The aim of this work was to used nanoclay filled nanocomposites with suitable properties for cable application like good flame-retardant property; improve dye-ability and resilience of polypropylene. The XRD results indicated an intercalated layer structure for nanocomposites, The SEM examination showed satisfactory dispersion of nanoclay in 2 wt% of C15A and some degree of agglomeration in 5 wt% of C15A. DSC analysis indicated that C15A acts as a nucleating agent and increases crystallinity in the nanocomposite. TGA showed with increasing nanoclay, heat resistance was improved and degradation temperatures increased. Limiting oxygen index (LOI) tests showed increased flame retardancy from 25% for neat polypropylene t0 32.2% for nanocomposites of 5 wt% of C15A. The tensile modulus was improved from 423 MPa for neat polypropylene to 474 MPa for nanocomposites with 5 wt% of C15A. This result indicates that increasing C15A content had a suitable effect on the tensile properties. Melt spinning investigation on low oriented yarn (LOY), draw textured yarn (DTY), and fully drawn yarn (FDY) of 2 wt% C15A nanocomposite showed a reduction of linear density for FDY and an increase of the shrinkage. Furthermore, the obtained results for the improvement of dye-ability and compression resilience showed that PP/C15A is appropriate for textile products. [ABSTRACT FROM AUTHOR]

In recent years, polymer matrix nanocomposites production and usage ratio is increased and therwithal the applicability of these composites to other areas has also improved significantly. Textile industry is one of these areas. With the used of polymer matrix nanocomposites in textile applications, it become possible to produced improved products with high strength, functional, antibacterial and good mechanical properties. Textile recycling yarns get popular day by day. Lots of textile company producing recycled PET fiber yarns and this is contributed to the environment. In this study recycled PET polymer was used as a matrix and enriched nanoparticles to investigate mechanic, microstructure and thermal properties. Melting method was used for producing of nanocomposite multifilament yarns. Filament thickness was 120 nm and TiO2, ZnO and CNT was used as a reinforcement to ratio %0.1, %0.3, %0.5 respectively. After analysis and experiments, it was seen clearly reinforcements was affected positively the mechnanical, microstructure and thermal properties of r-PET nanocomposites. According to the result of tensile strength tests, it was seen that CNT reinforcement increased tensile strength of r-PET polymer about %15. [ABSTRACT FROM AUTHOR]

The present research aimed to investigate the influence of Zr-based metal-organic framework, i.e. UiO-66, on the performance of poly(ethylene terephthalate) (PET) by the melt mixing method. PET/UiO-66 nanocomposites were prepared at 0.25, 0.5, 1, and 2 wt% of UiO-66. FESEM microphotographs showed the success of the melt mixing method in the fine dispersion of UiO-66 within PET. Additionally, XRD patterns confirmed that UiO-66 retained its structure after melt mixing at 260 ° C. DSC analysis suggested that UiO-66 acted as a nucleating agent with a best performance at 1 wt% loading, i.e. 45 % decrease in the crystallization half-time and 11 % increase in the crystallization temperature. Furthermore, the PET/UiO-66 nanocomposites exhibited an improvement in char formation and resistance to complete thermal degradation at high temperatures compared to neat PET. The inclusion of UiO-66 in PET increased the impact strength with a maximum value at 0.5 wt% loading, e.g. more than twice neat PET. In addition, DMTA results indicated that UiO-66 acted as a strengthening agent in PET. Rheological investigations revealed that PET/UiO-66 exhibits the non-Einstein-like viscosity behavior in which the complex viscosity decreased by increasing UiO-66 content. We reasoned that behavior mainly to the flexible nature of the UiO-66 particles. Although all the samples showed almost Newtonian behavior at 260 ° C in frequencies between 0.03 Hz and 100 Hz, PET/UiO-66 (0.5) presented the shear thinning behavior. This was ascribed to the good dispersion with the strong interfacial interaction, leading to a microstructure with yield stress. [Display omitted] • PET/UiO-66 nanocomposites were prepared via the melt mixing method. • UiO-66 acted as a nucleating agent with a best performance at 1 wt%. • The inclusion of UiO-66 increased the impact strength with a maximum value at 0.5 wt%. • UiO-66 acted as a strengthening agent in PET. • The complex viscosity of PET decreased steadily with the addition of UiO-66. [ABSTRACT FROM AUTHOR]

In this study, active biocomposite films of low-density polyethylene (LDPE) containing 5% wt. of curcumin, a natural chemical produced by some plants, are developed by melt extrusion and hot pressing. The detailed study of the physicochemical properties of the formed films demonstrates that the curcumin molecules, homogeneously dispersed in the whole volume of the LDPE matrix, cause a notable increase in the thermal stability of the LDPE polymer, without altering its thermal processability. At the same time the LDPE's water vapor barrier properties are significantly improved, while an effective antioxidant scavenging activity is observed against the 2,2-diphenyl-1-picrylhydrazyl free radicals (DPPH•). These results indicate that the developed active films based on the combination of LDPE and curcumin, following industrially applied preparation methods, are ideal candidates for active food packaging applications. Image 1 • Highly antioxidant food packaging films from low-density polyethylene (LDPE) and curcumin. • Excellent water vapor barrier properties. • High thermal stability without altering thermal processability. • Fabrication through industrially applicable methods. [ABSTRACT FROM AUTHOR]

Carbon black (CB)-filled polylactic acid (PLA) composites attract a significant interest due to their superior structural and functional performances. Properties of CB-filled PLA composites depend on physical and chemical interactions in them. In this study, interactions within CB (N220)-filled PLA composites as a function of processing method, filler concentration, and their effect on mechanical properties are investigated via mechanical tests. Strong interface interaction at intermediate concentration of 2.5 wt.% CB with PLA was confirmed through mechanical tests. Moreover, a 2.5 wt.% of CB-formed networks within PLA composites, which added the fracture resistance in the weaker phase, thereby improving their mechanical properties. Beyond 2.5 wt.%, a linked skeletal grid was formed, enhancing the fracture path in a weaker phase and deteriorating the mechanical properties. Experimental results on density and elastic modulus were compared with the theoretical model predictions. This study gives an insight on interactions controlling physical and mechanical properties related to various processing techniques and weight percent of CB in PLA composites. [ABSTRACT FROM AUTHOR]

Polypropylene (PP) composites including various amounts of silica aerogel (SA) microparticles were prepared by melt mixing in an internal mixer. The morphology and microstructure of the prepared composites were investigated by scanning electron microscopy (SEM). Mechanical properties of the samples, including elastic modulus, tensile stress, elongation and stress at break, were measured by tensile tests. In addition, the other mechanical features, including Izod impact strength, hardness and wear resistance, were evaluated and then related to the structure of the PP/SA composites. Furthermore, the thermal characteristics of the composites, such as heat deflection temperature and thermal stability, were studied by thermal gravimetric analysis (TGA). The SEM photographs indicated the satisfactory SA particles dispersion for the compositions of 1% and 3% but agglomeration of the aerogels at higher SA contents. Since the composites became stiffer, the impact and tensile strength decreased. The addition of the SA to the PP matrix yielded harder samples with lower weight loss and coefficients of friction in wear tests. The TGA evaluations confirmed that the presence of SA promoted and upgraded the thermal stability and heat deflection temperature of PP. The thermal results proved the superior potential of PP as an insulator when the SA particles were added. [ABSTRACT FROM AUTHOR]

Highlights • Biodegradable potato starch/PVA/rosin blends were developed. • Addition of rosin to the blends improves mechanical properties substantially. • Mechanical properties are comparable to those offered by polymers such as LDPE. • Starch/PVA/rosin blends could be interesting materials for packaging applications. Abstract Biodegradable potato starch/PVA samples containing different concentrations of rosin were prepared by melt-mixing in order to study the enhancement of the properties of native starch films. Glycerol and polyvinyl alcohol (PVA) are commonly used as plasticizers of starch. Their relatively low molecular weight (compared with starch) contributes to a good processability. Rosin is a renewable product whose incorporation in the starch/PVA matrix induces processing aid and reinforcing effects. Its relatively high molecular weight might prevent its migration to the surface of the final product. Water content, solubility in water, mechanical properties, microstructure and dynamic mechanical analysis of the samples were studied. The addition of 8% rosin to starch/PVA blends led to tensile strength values higher than 10 MPa and elongation at break values close to 2000%, values comparable to those offered by conventional polymers used in food packaging, for example LDPE. Furthermore, starch compounds have low cost and high biodegradability. [ABSTRACT FROM AUTHOR]

Abstract The migration of clay particles during mixing of organically montmorillonite polyethylene/polyamide nanocomposites was investigated. Special attention was paid to the observation of PA droplet morphology establishment as well as clay localization and exfoliation at different mixing times. During the incorporation step in internal mixer, the simultaneous mixing of all components favors the presence of a great number of micrometric clay agglomerates within the matrix. The migration of clay particles from the polyethylene (PE) matrix towards the polyamide (PA) dispersed phase is a very short process that takes about 1 min. From the beginning of the dispersion step (~2 min), clay particles are exclusively localized at the PA droplet frontier. Then, they are sheared and redistributed, forming a nanometric interphase. The correlation between droplet morphology establishment and clay migration mechanisms until the formation of a developed interphase is discussed. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract The aim of the present study was to evaluate the thermodynamic properties of in-situ formation of cocrystal formulations by the melt-mixing method. Specifically, the thermodynamic mixing behaviour of carbamazepine-nicotinamide and ibuprofen-nicotinamide cocrystals prepared with the aid of Soluplus® (SOL) were evaluated using thermodynamic lattice-based solution theories. Thermodynamic miscibility of both cocrystals with SOL was predicted by calculating Gibb′s free energy based on the Flory-Huggins (FH) interaction parameter (χ), while the activity coefficient of cocrystals estimated with the aid of solid–liquid equilibrium equation and FH lattice theory, showed good thermodynamic miscibility of the components at elevated temperatures used normally during melt-mixing based processes. Complete phase transition diagrams constructed with the aid of DSC measurements and FH solution theory, suggested the existence of two transition zones: (1) a stable cocrystal zone, located at the right-hand-side of the spinodal phase separation curve, where stable cocrystals are prepared and (2) an unstable cocrystal zone, located at the left-hand-side of the spinodal curve up to liquidus, where the matrixforming polymer sets a kinetic barrier to recrystallization and hence, a barrier to the formation of cocrystals. The validity of the suggested thermodynamic phase transition zones was experimentally verified by ATR-FTIR and hot-stage polarized light microscopy. [ABSTRACT FROM AUTHOR]

In all fields of industry it is important to produce parts with good quality. Injection molded parts usually have to meet strict requirements technically and aesthetically. The aim of the measurements presented in our paper is to investigate the aesthetic appearance, such as surface color homogeneity, of injection molded parts. It depends on several factors, the raw material, the colorants, the injection molding machine and the processing parameters. In this project we investigated the effects of the injection molding machine on surface color homogeneity. We focused on injection molding screw tips and investigated five screw tips with different geometries. We produced flat specimens colored with a masterbatch and investigated color homogeneity. To evaluate the color homogeneity of the specimens, we used digital image analysis software developed by us. After that we measured the plastication rate and the melt temperature of the polymer melt because mixing depends on these factors. Our results showed that the screw tips (dynamic mixers) can improve surface color homogeneity but they cause an increase in melt temperature and a decrease in the plastication rate. [ABSTRACT FROM AUTHOR]

In this work, design and development of a new melt mixing method and corresponding mixer for polymer materials were reported. Effects of ultrasonic power and sonication time on the carbon nanotubes (CNTs) filled ultra high molecular weight polyethylene (UHMWPE) nanocomposites were experimentally studied. Transmission Electron Microscopy images showed that homogeneous dispersion of CNTs in intractable UHMWPE matrix is successfully realized due to the synergetic effect of ultrasonic wave and extensional deformation without any aid of other additives or solvents. Differential scanning calorimetry results revealed an increase in crystallinity and crystallization rate due to the finer dispersion of the CNTs in the matrix which act as nucleating point. Composites’ complex viscosity and storage modulus decreased sharply at first and then leveled off with the increase of sonication time or the ultrasonic power. The thermal stability and the tensile strength of the CNTs/UHMWPE nanocomposites improved by using this novel mixing method. This is the first method that combined the ultrasonic wave and the extensional deformation in which the elongation rate, sonication time and ultrasonic power can be adjusted simultaneously during mixing. The novel mixer offers several advantages such as environment-friendly, high mixing efficiency, self-cleaning and wide adaptability to materials. [ABSTRACT FROM AUTHOR]

The purpose of the present study was to use commercial available polymers like PVP/PEG, soluplus® and kollidon® SR to prepare immediate and sustained release formulations of felodipine by hot melt mixing method. Solid dispersions containing 5, 10, 20 and 30 wt% drug have been prepared in a Haake-Buchler Reomixer at melt temperature 130 °C and mixing time 10 min. As was found from DSC and XDR studies completely amorphous and miscible solid dispersions can be prepared. In all cases a single glass transition was recorded, which is depended from the used drug amount. Hydrogen bonds and the molecular interaction between felodipine and polymer matrices are responsible for the miscibility of prepared formulations. This has as result the substantial enhancement of felodipine release rate in PVP/PEG mixture and due to the high solubility of used polymers immediate release formulations have been prepared. On the contrary, sustained release formulations can be prepared in the case of kollidon SR solid dispersions. The release mechanism of all preparations was studied using different kinetic models. Finally, binding affinity values calculated by molecular docking simulations were used as estimators for predicting long-term drug's physical stability in solid dispersions. [ABSTRACT FROM AUTHOR]

The redox state of volcanic products determines their leverage on the oxidation of Earth's oceans and atmosphere, providing a long-term feedback on oxygen accumulation at the planet's surface. An archive of redox conditions in volcanic plumbing systems from a magma's mantle source, through crustal storage, to eruption, is carried in pockets of melt trapped within crystals. While melt inclusions have long been exploited for their capacity to retain information on a magma's history, their permeability to fast-diffusing elements such as hydrogen is now well documented and their retention of initial oxygen fugacities ( f O 2 ) could be similarly diffusion-limited. To test this, we have measured Fe 3+ /ΣFe by micro-XANES spectroscopy in a suite of 65 olivine-hosted melt inclusions and 9 matrix glasses from the AD 1783 Laki eruption, Iceland. This eruption experienced pre-eruptive mixing of chemically diverse magmas, syn-eruptive degassing at the vent, and post-eruptive degassing during lava flow up to 60 km over land, providing an ideal test of whether changes in the f O 2 of a magma may be communicated through to its cargo of crystal-hosted melt inclusions. Melt inclusions from rapidly quenched tephra samples have Fe 3+ /ΣFe of 0.206 ± 0.008 (ΔQFM of +0.7 ± 0.1), with no correlation between their f O 2 and degree of trace element enrichment or differentiation. These inclusions preserve the redox conditions of the mixed pre-eruptive Laki magma. When corrected for fractional crystallisation to 10 wt.% MgO, these inclusions record a parental magma [Fe 3+ /ΣFe] (10) of 0.18 (ΔQFM of +0.4), significantly more oxidised than the Fe 3+ /ΣFe of 0.10 that is often assumed for Icelandic basalt magmas. Melt inclusions from quenched lava selvages are more reduced than those from the tephra, having Fe 3+ /ΣFe between 0.133 and 0.177 (ΔQFM from −0.4 to +0.4). These inclusions have approached equilibrium with their carrier lava, which has been reduced by sulfur degassing. The progressive re-equilibration of f O 2 between inclusions and carrier melts occurs on timescales of hours to days, causing a drop in the sulfur content at sulfide saturation (SCSS) and driving the exsolution of immiscible sulfide globules in the inclusions. Our data demonstrate the roles of magma mixing, progressive re-equilibration, and degassing in redox evolution within magmatic systems, and the open-system nature of melt inclusions to f O 2 during these processes. Redox heterogeneity present at the time of inclusion trapping may be overprinted by rapid re-equilibration of melt inclusion f O 2 with the external environment, both in the magma chamber and during slow cooling in lava at the surface. This can decouple the melt inclusion archives of f O 2 , major and trace element chemistry, and mask associations between f O 2 , magmatic differentiation and mantle source heterogeneity unless the assembly of diverse magmas is rapidly followed by eruption. Our tools for understanding the redox conditions of magmas are thus limited; however, careful reconstruction of pre- and post-eruptive magmatic history has enabled us to confirm the relatively oxidised nature of ocean island-type mantle compared to that of mid-ocean ridge mantle. [ABSTRACT FROM AUTHOR]

Tailoring the properties of natural polymers such as electrical conductivity is vital to widen the range of future applications. In this article, the potential of electrically conducting multi-wall carbon nanotube (MWCNT)/polylactic acid (PLA) composites produced by industrially viable melt mixing is assessed simultaneously to MWCNT influence on the composite’s mechanical strength and polymer crystallinity. Atomic force microscopy observations showed that melt mixing achieved an effective distribution and individualization of unmodified nanotubes within the polymer matrix. However, as a trade-off of the poor tube/matrix adhesion, the tensile strength was lowered. With 10 wt% MWCNT loading, the tensile strength was 26% lower than for neat PLA. Differential scanning calorimetric measurements indicated that polymer crystallization after injection moulding was nearly unaffected by the presence of nanotubes and remained at 15%. The resulting composites became conductive below 5 wt% loading and reached conductivities of 51 S m−1 at 10 wt%, which is comparable with conductivities reported for similar nanocomposites obtained at lab scale. [ABSTRACT FROM AUTHOR]

Synthetic biopolymers have made significant inroads into the development of devices for tissue regeneration. In this context, a challenge is the achievement of appropriate properties mimicking the natural extracellular matrix by fabricating scaffolds presenting mechanical properties, specific surface, porosity and pore interconnection adequate for the final application. This study involved a systematic procedure based on Taguchi method for parameters optimization of melt mixing/particulate leaching combined processes aiming to enhance the performance of the scaffolds. In particular, it was evaluated the effect of time and temperature of melt mixing of the poly(lactic acid) matrix with two water-soluble inorganic porogen agents (i.e. NaCl or CaCl 2 ) with two different pore size and poly(ethylene glycol). Thereafter, the blends were compression molded and water-leached for different time and at different pH. By adopting L 8 Taguchi orthogonal array, seven control factors, each at two levels, were tested, and ANOVA was applied to find the statistically significant factors and the combination of their optimal levels. The results revealed that the mixing temperature had the highest effect on mechanical properties. Moreover, the internal architecture of the scaffolds was studied by morphological analysis, finding that it is affected by the kind of porogen salt and by mixing time. [ABSTRACT FROM AUTHOR]

High density polyethylene (HDPE) was compounded with thermally exfoliated graphene oxide (TEGO) by thermokinetic mixing in a short time. High shear rates during the compounding process provided high exfoliation and proper dispersion of graphene layers in the polymer matrix. Different TEGO/polymer ratios were used to get efficient melt mixing. Structural analysis by spectroscopic techniques confirmed the exfoliation of TEGO sheets and the coverage of their surfaces by HDPE chains. Furthermore, homogeneous dispersion of graphene sheets in the matrix led to the enhancement in the mechanical and thermal properties of HPDE-based nanocomposites. Especially stress concentration sites were significantly reduced by preventing the agglomeration and restacking of graphene sheets in the matrix. Therefore, the tensile modulus and strength of HDPE nanocomposite increased about 36.5% and 45.7%, respectively, with the incorporation of 2 wt% TEGO. Microscopy analysis showed the separation of graphene layers in the cross-sectional area of composite specimens. TEGO-reinforced HDPE nanocomposites showed high thermal stability compared to the neat sample. [ABSTRACT FROM AUTHOR]

In polymer composites, filler dispersion and interfacial adhesion are two critical factors in determining their properties. To date, it still remains a challenge to achieve uniform filler dispersion and implement interfacial tailoring in rubber composites by direct melt mixing. In this study, we prepared graphene oxide (GO) slurry in acetone via a simple solvent exchange method and modified GO in the slurry. Then the slurry was compounded with nitrile rubber on two-roll mill to produce composites. Morphological and interfacial structural studies revealed that GO was dispersed at nano-scale in the composites, and the dispersion of GO and interfacial adhesion were further improved upon the modification of GO with silane. Consequently, the mechanical properties of the composites were remarkably enhanced by adding GO. [ABSTRACT FROM AUTHOR]

Polylactide (PLA) composites with three types of fillers, calcium carbonate, barium sulfate, and mica, have been prepared. Methods of preparation were melt mixing in a Brabender plasticorder at 190 °C and solution mixing in chloroform. The concentration of added fillers was: 0.1, 1, and 5 mass% (only by melt mixing). Thermal properties of prepared composites were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis. The dispersity of filler in matrix was examined by scanning electron microscopy. There was no agglomeration in any composites. Results of DSC analysis reveal the influence of preparation method on thermal transitions. By the melt mixing method, the introduced filler hindered crystallization but caused mostly just a slight increase in T relative to pure PLA (57.4 °C). By solution-mixing method, the absence of crystallization is noticed in all samples. Concurrently composites displayed T higher for ca. 5-6 °C relative to pure PLA (53.3 °C), with the exception of composite with smallest content of calcium carbonate nanofiller. Thermal stability is improved in all composites, regardless of the filler used and preparation method. It is especially pronounced regarding decomposition temperature (5 mass% loss) where the increase ranges from 11 up to 55 °C in case of melt mixing and 17-35 °C for solution mixing. [ABSTRACT FROM AUTHOR]

The preparation of nanocomposites of low-density polyethylene (LDPE) and cellulose nanocrystals (CNCs) isolated from cotton or produced in situ by the dispersion of microcrystalline cellulose (MCC) is reported. The hydrophobic matrix polymer and the rather polar filler particles appear to be difficult to mix, but it is shown here that composites with significantly improved mechanical characteristics and of homogeneous appearance can be produced using an organic-solvent-free two-step process. This is achieved by first mixing an aqueous slurry of an LDPE powder with an average particle size of <600 μm with aqueous suspensions of CNCs or MCC and removing most, but not all, of the water. Compounding such water-plasticized mixtures in a roller-blade mixer and subsequent compression-molding afford highly transparent films, whose room-temperature storage modulus is increased by a factor of 2.5 upon incorporation of 15% w/w CNCs or MCC. The results demonstrate that LDPE/nanocellulose composites with improved mechanical properties can be produced by an organic solvent-free process that appears to be scalable to industrial production scale. [ABSTRACT FROM AUTHOR]

An intermeshing corotating twin-screw extruder is often used for producing polymer composites. In this study, we discussed mixing performance of special rotor segments in molten zone. These rotor segments have several tip clearances for achievement of self-cleaning and effective mixing, and these are named various clearance mixing technology. We studied about dispersive mixing performance of configuration, which consists of various clearance mixing technologys (various clearance mixing technology configuration) using numerical analyses and experiments. For the analytical evaluation of mixing performance, we have adopted a particle tracking method. As evaluation indices of dispersive mixing performance, we focused on following three values (1) maximum value in a history of first principal stress of each particle, (2) time-integrated shear rate of each particle, and (3) time-integrated first principal stress of each particle. And we made the probability distributions of the indices. We adopted weighted probability as approximation of volume probability in each region. The results were compared with those of kneading disk segments configuration (kneading disk configuration). Furthermore, we validated the accuracy of the analytical evaluation by performing experiments under same conditions as those of numerical analyses. For the experimental evaluation of mixing performance, we used twin-screw extruder. Polypropylene was selected as suspending media. And CaCO3was selected as filler. To compare just the mixing performance of various clearance mixing technology configuration with that of kneading disk configuration, side feeding and screw configuration which had third mixing segments zone were adopted. From the experimental result, it is found that various clearance mixing technology configuration dispersed better than kneading disk configuration. And from the comparison between the experimental evaluation and the analytical evaluation, it is found that the first principal stress is more appropriate for evaluation index of dispersive mixing. Finally, it can be mentioned that various clearance mixing technology configuration has better mixing performance than kneading disk configuration, and large stress is important for dispersive mixing. [ABSTRACT FROM AUTHOR]

Lignocellulosic nanostructures, mainly cellulose and lignin based materials, have recently attracted much attention due to their renewable nature, wide variety of source materials available throughout the world, low cost and density, high surface functionality and reactivity. The exceptional mechanical strength, together with high aspect ratio and large surface area, enable these nanomaterials to reinforce a wide variety of polymers even at very low filler loadings. Furthermore, nanocomposite approach has emerged in the last two decades as an efficient strategy to upgrade the structural and functional properties of natural and/or synthetic polymers. The combination of bioresorbable and sustainable polymers with bio-based nanostructures opened new perspectives in the self-assembly of nanomaterials for different applications with tuneable mechanical, thermal and degradative properties. In the present paper, the effect of introduction of lignocellulosic reinforcement phases (cellulosic and lignin based nanostructures), on structural and functional properties of several thermoplastic polymer matrices was investigated at the nanoscale level. Both solvent casting and melt compounding were considered as processing techniques for the proposed nanocomposite formulations. The role of cellulose and lignin based nanostructures, such as their synergic action when embedded in a polymer matrix, were analysed (taking into account the required functionality of the systems in the appropriate final applications) and reported in terms of morphological, optical, thermal, chemical, mechanical, barrier and degradative performance. [ABSTRACT FROM AUTHOR]

In order to develop scaffold able to mimic the natural gradient properties of tissues, biphasic and triphasic approaches were adopted. In this work, polycaprolactone/polyethylene glycol (PCL/PEG) scaffolds were prepared by using a combination of melt mixing and selective leaching without harmful solvents. The method permitted to develop three-layer scaffolds with high control of porosity and pore size. The mechanical properties were evaluated under physiological condition in order to simulate the real conditions of work. Co-culture of osteoblastic and fibroblastic mice cells were carried out in order to study the differential cellular permeation through the different pore size layers. [ABSTRACT FROM AUTHOR]

In present study, styrene-b-(ethylene-co-butylenes)-b-styrene triblock copolymer (SEBS) and polypropylene (PP) are prepared. This mixing is followed by adding 3, 5 and 10 wt% of nano CaCO3. The morphology and thermal behavior of PP/SEBS/nano-CaCO3 compounds are characterized by different methods. Scanning electron microscopy micrographs of cryo-fractured PP/SEBS/nano-CaCO3 nanocomposites show that with increasing nano-CaCO3 loading, the aggregation becomes worse. However, followed by adding 5 wt% nano-CaCO3 into PP/SEBS nanocomposites, nano-CaCO3 is homogeneously dispersed in PP matrix. The photomicrograph of transmission electron microscopy confirms that SEBS/PP/nano-CaCO3 nanocomposites are formed, as low aggregations of calcium carbonate were well-dispersed in polymer matrix. With a rise in nano-filler content, the tensile and impact strength of PP/SEBS/CaCO3 nanocomposite are fixed while the elastic modulus of PP/SEBS nanocomposites increases followed by adding nano-CaCO3 to polymer blend, which could be due to the acceptable nano-CaCO3 dispersion quality. [ABSTRACT FROM AUTHOR]

Conductive polymer nanocomposites based on carbon nanotubes (CNTs) have wide range of applications in the electronics and energy sectors. For many of these applications, such as the electromagnetic interference (EMI) shielding, high nanofiller loading is typically needed to achieve the desired properties. The high nanofiller concentration deteriorates the composite's tensile strength due to the increase in nanofiller aggregation. In this work, highly conductive CNT/polypropylene (PP) nanocomposite with improved tensile strength was prepared by melt mixing. The effects of CNT content on the processing behavior, microstructure, mechanical and electrical properties of the nanocomposite were investigated. Scanning electron microscopy was used to investigate the composite microstructure. Good level of CNT dispersion with remarkable adhesion at the CNT/PP interface was observed. Based on a theoretical model, the interfacial strength was estimated to be in the range of 36-58 MPa. As a result of thismicrostructure, significant enhancement in ultimate tensile strength was reported with the increase of CNT content. The tensile strength of the 20wt.% CNT/PP nanocompositewas 80% higher than that of the unfilled PP.Moreover, and due to the good dispersion of CNT particles, an electrical percolation threshold concentration of 0.93 wt.% (0.5 vol.%) was obtained. [ABSTRACT FROM AUTHOR]

The pre-eruptive water content of magma is often estimated using crystal-hosted melt inclusions. However, olivine-hosted melt inclusions are prone to post-entrapment modification by H + diffusion as they re-equilibrate with their external environment. This effect is well established for the case of H + loss from olivine-hosted inclusions that have cooled slowly in degassed magma. Here we present evidence for the opposite effect: the addition of H + into inclusions that are held in melts that are enriched in H 2 O with respect to the trapped melts. The compositional variability in a suite of 211 olivine-hosted inclusions from the Laki and Skuggafjöll eruptions in Iceland's Eastern Volcanic Zone indicates that diffusive H + gain governs the H 2 O content of incompatible trace element depleted inclusions. Individual eruptive units contain olivine-hosted inclusions with widely varying incompatible element concentrations but near-constant H 2 O. Furthermore, over 40% of the inclusions have H 2 O / Ce > 380 , significantly higher than the H 2 O/Ce expected in primary Icelandic melts or mid-ocean ridge basalts (150–280). The fact that the highest H 2 O/Ce ratios are found in the most incompatible element depleted inclusions indicates that hydration is a consequence of the concurrent mixing and crystallisation of compositionally diverse primary melts. Hydration occurs when olivines containing depleted inclusions with low H 2 O contents are juxtaposed against more hydrous melts during mixing. Melt inclusions from a single eruption may preserve evidence of both diffusive H + loss and H + gain. Trace element data are therefore vital for determining H 2 O contents of melt inclusions at the time of inclusion trapping and, ultimately, the H 2 O content of the mantle source regions. [ABSTRACT FROM AUTHOR]

The solidification of microstructure of hypereutectic Al-20%Si alloy obtained by mixing high-temperature Al-30%Si alloy melt and low-temperature Al-10%Si alloy melt in a mixing ratio of 1 : 1 was investigated by optical microscopy. A certain amount of AlTi5BRE10 inter alloy was added into high-temperature Al-30%Si alloy melt before mixing. The results showed that the primary Si crystals were refined and passivated by the melt mixing process and a certain amount of AlTi5BRE10 inter alloy further refined the primary silicon and α-Al phase. The coarse plates, petals and irregular triangular-shaped primary Si crystals turned into fine block shapes, and the α-Al phases were spherical. After the melt mixing treatment, the microstructure of the hypereutectic Al-20%Si alloy was composed of a primary α-Al phase, eutectic (α + Si) phase, and the primary silicon, which caused the hypereutectic Al-20%Si alloy to exhibit typical hypoeutectic and hypereutectic characteristics. [ABSTRACT FROM AUTHOR]

Nanocomposites of high density polyethylene (HDPE), linear low density polyethylene (LLDPE), polypropylene (PP), polystyrene (PS) and polycarbonate (PC) with thermally reduced graphene were generated by melt mixing. The HDPE nanocomposites had increment in the tensile (>50%) and storage modulus as a function of filler fraction. LLDPE had the highest enhancements of ≈100% in tensile modulus, 60% in break stress and 30% in tensile stress. PS exhibited least extent of property improvement, though the absolute modulus and strength were the highest for PS nanocomposites indicating the final properties of nanocomposites result from a combination of factors like polarity match between polymer and filler, processing conditions and physical properties of the polymer matrix. [ABSTRACT FROM AUTHOR]

The effect of adding carbon black on the electrical and rheological properties of graphite nanoplatelets/poly(ethylene- butyl acrylate) copolymer composites produced via melt or solution mixing was studied. By adding a small amount of low- or high-structured carbon black to the nanocomposite, the electrical percolation threshold decreased and the final conductivity (at higher filler contents) increased. The effect on the percolation threshold was significantly stronger in case of the high-structured carbon black where replacing 10 wt% of the total filler content with carbon black instead of graphite nanoplatelets reduced the electrical percolation threshold from 6.9 to 4.6 vol%. Finally, the solution mixing process was found to be more efficient leading to a lower percolation threshold. For the composites containing high-structured carbon black, graphite nanoplatelets and their hybrids there was a quite reasonable correlation between the electrical and rheological percolation thresholds. [ABSTRACT FROM AUTHOR]

• PLA/SiO2:Sr2+: Tb3+ composites were successfully synthesized by melt mixing and characterized. • TEM and XRD were used to determine the physical properties. • The thermal properties of the composites were determined using DSC and TGA. • Photoluminescent behavior of the composites was studied with laser PL. • All the samples emit in the blue vertex as shown by the CIE results. SiO 2 :0.4% Sr2+, x% Tb3+ (0 ≤ x ≤ 0.5) nanophosphor powders were prepared by sol-gel method. The powder samples were dispersed into the PLA polymer matrix through melt mixing method and compression molding to prepare the nanophosphor polymer composite. X-ray diffraction (XRD) patterns showed broad peaks with the position of the peaks shifting and more separating with an increase in Tb3+ concentration. The transmission electron microscope (TEM) images showed darker patches with the introduction of the nanophosphor, which indicates the incorporation of phosphor particles into PLA polymer. Differential scanning calorimeter (DSC) results revealed that the composites show an increase in the cold crystallization temperature (T cc) and slight decrease in the glass transition temperature (T g) as compared to the PLA. Thermogravimetric analysis (TGA) results showed that the thermal stability of the composites show an initial decrease with the incorporation of the fillers, but they become more thermally stable with higher Tb concentration in the fillers. Ultraviolet visible spectroscopy (UV–vis) results showed the decrease in transmittance for the composite compared to the PLA polymer. The photoluminescence (PL) results showed that the incorporation of the Sr2+doped SiO 2 only affected the luminescence intensity, while co-doping with the incorporation of the Sr2+ and Tb3+ ions induced the emissions peaks at 487, 543, 582 and 621 nm, which could be attributed to the 5D 4 → 7F 3 , 7F 4 , 7F 5 , and 7F 6 transitions of Tb3+, respectively. The main aim of this study was to fabricate the light emitting polymer-based material. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: Major elements, trace elements and volatiles were measured in 110 olivine-hosted melt inclusions from the subglacial Skuggafjöll eruption in the Eastern Volcanic Zone of Iceland. Variations in melt inclusion trace element concentrations can be accounted for by incomplete mixing of diverse mantle parental melts accompanied by variable extents of fractional crystallisation. Binary mixing between an incompatible trace element-enriched and depleted melts provides a good fit to observed variations in trace element ratios such as Ce/Y. Surprisingly, the CO2 contents of melt inclusions correlate negatively with their degree of trace element enrichment. Depleted, low-Ce/Y inclusions with ∼1200 ppm CO2 have high CO2/Nb contents (∼400), suggesting that melts experienced little or no CO2 exsolution before inclusion entrapment. Enriched, high-Ce/Y inclusions contain ∼300 ppm CO2, have low CO2/Nb (contents 50–100) and melts are likely to have exsolved much of their original CO2 contents prior to inclusion entrapment. The negative correlation between CO2 content and trace element enrichment may arise either from the more efficient exsolution of CO2 from enriched melts, or from the intrusion of CO2-supersaturated depleted melts into enriched melts that had already exsolved much of their original CO2 contents. Some inclusions have lower CO2 contents than predicted from binary mixing models, which suggests that at least some CO2 exsolution occurred concurrently with mixing. Enriched inclusions record entrapment pressures of ∼0.5 kbar. These pressures probably correspond to the depth of mixing. Higher pressures recorded in depleted inclusions may have resulted from the development of CO2 supersaturation during ascent from storage at ≥1.5 kbar. The presence of CO2 supersaturation in melt inclusions has the potential to constrain timescales of melt inclusion entrapment. [Copyright &y& Elsevier]

Electrically conductive polypropylene nanocomposites containing multi-walled carbon nanotubes were produced by melt blending by dilution of a concentrate masterbatch containing 10 wt.% of filler. In order to promote polymer infiltration within primary agglomerates a ultra-low melt viscosity polypropylene grade has been used for masterbatch production. Moreover, three polypropylenes with different melt viscosities have been used for successive dilutions. Filler dispersion has been assessed by both indirect macroscale analyses and direct morphological investigations. Characterization showed percolation thresholds occurring for very low filler contents. During dilution, lower polymer viscosities lead to more effective residue agglomerates dispersion, hence better electrical properties. [ABSTRACT FROM AUTHOR]

Abstract: The nature of magmatic sources reflected by isotopic composition of the ocean island basalt (OIB) remains an on-going question in igneous geochemistry. To constrain the magmatic sources for OIB related to the Kerguelen plume activity, we performed detailed microanalytical investigation of the 21.4Ma picritic basalt (MD109-D6-87) dredged during the “Marion Dufresne” cruise on a seamount between Kerguelen Archipelago and Heard Island. Lead isotope compositions of olivine-hosted melt inclusions and matrix glasses were measured by Laser Ablation Multiple Collector Inductively Coupled Plasma Mass Spectrometry (LA-MC-ICP-MS) and Secondary Ion Mass Spectrometry (SIMS). We also performed major and trace element microanalyses and mapping of the inclusions and the host olivine phenocrysts by electron microprobe (wavelength-dispersive X-ray spectroscopy, WDS). The observed significant major element (K2O/P2O5, Al2O3/TiO2) and Pb isotope (207Pb/206Pb and 208Pb/206Pb) heterogeneities of parental melts (MgO=7–10wt.%) during early high pressure crystallisation stage (200–300MPa, Fo82–86 mol%), and relative homogeneity at later lower-pressure crystallisation stage (<100MPa, Fo75–80 mol%) are interpreted by mixing between “Plume” and “Assimilant” melts during magma residence and transport. Lead isotope composition of the parental basaltic melts was inherited from both heterogeneous mantle and the Kerguelen Plateau crust. High K2O/P2O5 (>4), Al2O3/TiO2 (>4) ratios are attributed to assimilation of the plateau basaltic crust (≥50wt.%) by the melts in the magma chamber at palaeodepths from 6 to 9km. The crustal assimilation may have happened through plagioclase dissolution. The large chemical and isotopic heterogeneity of the parental OIB melts found by in situ microanalyses in this study suggests that the bulk rock chemistry alone cannot provide enough information to constrain the nature of the magmatic sources. [Copyright &y& Elsevier]

The relationship between varying processing variables, rotor speed (50 to 200 rpm) and mixing time (10 to 30 min), and MWCNT loading (0.5 to 2.0 wt%), on MWCNT dispersion in a poly(propylene) during batch melt mixing was investigated. MWCNT dispersion was improved by increasing rotor speed and/or mixing time, 200 rpm and 30 min being optimum, although composites prepared employing 100 rpm and 20 min were the most electrically conducting, (<100 S cm−1). PP shear viscosity increased with increasing MWCNT loading yielding a rheological percolation of ∼0.5 wt% MWCNTs. Volume resistivity of the composites decreased with increasing rotor speed and for mixing times up to 20 min only, the former yielding an electrical percolation of ∼0.65 wt% MWCNTs at 200 rpm. [ABSTRACT FROM AUTHOR]

Abstract: Platinum-group minerals are the dominant control on the budget of platinum-group elements in ophiolitic chromitites. They vary widely in distribution, morphology, chemistry and Os-isotope compositions. Their distribution in different types of chromitites, and different microstructural sites within them may reflect the role of chromite as a physical “collector” of the platinum-group elements during crystallisation of both phases from melts. The platinum-group minerals show significant Os-isotope heterogeneity on the scale of single micrometric grains enclosed within individual chromite grains. This micro-scale isotopic heterogeneity, and their random spatial distribution within the chromites, argue strongly against an origin of the platinum-group minerals via exsolution from the chromite lattice during post-magmatic cooling. A re-interpretation of their microstructures and Os isotopes analysed in situ had led us to review the traditional models, and to propose several origins for the platinum-group minerals in chromitites. (1) The suites of platinum-group minerals mainly record crystallisation during mixing of multiple different melts and physical entrapment in chromite. (2) Some platinum-group minerals in chromitites may have been scavenged from wall–rock peridotite during migration of the parental melts of the chromitite. (3) Other platinum-group minerals may have precipitated from metasomatic fluid/melts that infiltrated existing chromitites. The recrystallization of pre-existing platinum-group minerals during polyphase metamorphism or “recycling” of the chromitite into deeper mantle levels can explain the presence of micrometric platinum-group minerals with distinct Os-isotope compositions. [Copyright &y& Elsevier]

Late-orogenic Pan-African tectonics formed an 8km long fault-fracture zone in the shallow foreland crust of the Gariep Orogen in Mesoproterozoic granitoid basement. Pseudotachylyte was locally formed during a single seismic event that caused brittle failure in cohesive quartz-diorite, granodiorite and granitic gneiss. 40Ar/39Ar laser spot analysis provides an age of 512.5±7.5Ma for this seismic event. The depth of the hypocentre between 1700 and 5300m is inferred from the likely thickness of the overlying rock at that time. Abundant quartz melting in conjunction with low host rock temperature indicates a minimum seismic temperature rise exceeding 1030°C but in some samples dry quartz melting at temperatures exceeding 1700°C might have been possible. The abundance of hydrous phases in the host rock controlled the volume of melt produced in a given host rock type. Different types of primary melt were formed by the fusion of batches of host rock with different relative proportions of plagioclase, alkali feldspar, quartz, biotite, and, where present, amphibole or garnet. The chemical and physical interaction between these melts depended on contrasting melt mobility and viscosity. In quartz-diorite, glasses of variable composition are well preserved and show the distribution of primary melt species at the time of quenching. These different melt species had limited tendency of mixing, unless mixing was assisted by syn-seismic shearing. In granodiorite, which has a low proportion of hydrous phases, low-viscosity melt was formed at high temperatures, eliminating most host rock fragments and leading to extensive melting of quartz. The low melt viscosity, probably further decreased by the dissolution of free H2O, permitted effective melt homogenisation in such veins. Still in the liquid state these melts segregated, effectively separating secondary melts of sodic–calcic and of K–Mg–Fe-rich composition. After quenching the solid state diffusion of cations in glass was comparatively insignificant. [ABSTRACT FROM AUTHOR]

Abstract: The effect of plasticizer’s (PEG) molecular weight (MW) on PVP based solid dispersions (SDs), prepared by melt mixing, was evaluated in the present study using Tibolone as a poorly water soluble model drug. PEGs with MW of 400, 600, and 2000g/mol were tested, and the effect of drug content, time and temperature of melt mixing on the physical state of Tibolone, and the dissolution characteristics from SDs was investigated. PVP blends with PEG400 and PEG600 were completely miscible, while blends were heterogeneous. Furthermore, a single Tg recorded in all samples, indicating that Tibolone was dispersed in a molecular lever (or in the form of nanodispersions), varied with varying PEG’s molecular weight, melt mixing temperature, and drug content, while FTIR analysis indicated significant interactions between Tibolone and PVP/PEG matrices. All prepared solid dispersion showed long-term physical stability (18months in room temperature). The extent of interaction between mixture components was verified using Fox and Gordon–Taylor equations. Artificial neural networks, used to correlate the studied factors with selected dissolution characteristics, showed good prediction ability. [Copyright &y& Elsevier]