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Melt Mixing (melt + mixing)
Selected AbstractsMelt Mixing of Ethylene/Butyl Acrylate/Glycidyl Methacrylate Terpolymers with LDPE and PETMACROMOLECULAR MATERIALS & ENGINEERING, Issue 2 2009Aida Benhamida Abstract The chemical modification by melt-mixing of an EBAGMA terpolymer with LDPE and PET was investigated with the aim to use these EBAGMA/LDPE and EBAGMA/PET blends (in equal weight quantities) as compatibilizer master batches to improve the compatibility of the LDPE/PET system. It is shown that when the EBAGMA terpolymer is melt blended with LDPE, almost 40% of the initial amount of EBAGMA is linked to the LDPE backbone. In contrast, in the case of EBAGMA/PET, FT-IR spectra indicate the total reactivity between the two components through the reaction of the epoxy group of EBAGMA with the PET terminal groups. SEM analysis shows that both master batches present two well-interconnected phases. [source] Melt mixing of carbon fibers and carbon nanotubes incorporated polyurethanesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Shahrul Azam Abdullah Abstract Polyurethane composites filled with carbon fibers (CF) and carbon nanotubes (CNT) were prepared by mixing and injection molding, and its mechanical as well as their thermal properties were investigated. Dynamic mechanical analysis (DMA), thermogravimetry analysis (TGA), and thermal conductivity tests were done, and the properties were evaluated as a function of the filler concentration. The storage modulus of the composites increased with fillers concentration, which also mean the increase of the stiffness, suggest a good adhesion between the polyurethane matrix and the fillers. Addition of more CF and CNT to the composites broadened and lowered the peak of tan , specifies that the polyurethane composite became more elastic because there is a good adhesion between the fillers and the matrix. The addition of carbon fillers improves the thermal stability of the polyurethane. The inclusions of CNT show a better thermal stability when compared with CF. The addition of carbon fillers also increased the thermal conductivity of the polyurethane composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Structure and properties of phase change materials based on HDPE, soft Fischer-Tropsch paraffin wax, and wood flourJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2010M. E. Mngomezulu Abstract Phase-change materials based on high density polyethylene (HDPE), soft Fischer-Tropsch paraffin wax (M3), and alkali-treated wood flour (WF) were investigated. The blend and composite samples were prepared by melt mixing using a Brabender Plastograph, followed by melt pressing. They were characterized in terms of their morphology, as well as thermal, mechanical, thermo-mechanical, and water absorption properties. Although SEM micrographs showed some evidence of intimate contact between the WF particles and the HDPE matrix as a result of alkali treatment, poor filler dispersion, and interfacial adhesion were also observed. Partial immiscibility of the HDPE and the M3 wax was noticed, with the WF particles covered by wax. There was plasticization of the HDPE matrix by the wax, as well as partial cocrystallization, inhomogeneity and uneven wax dispersion in the polymer matrix. The HDPE/WF/M3 wax composites were more homogeneous than the blends. The presence of wax reduced the thermal stability of the blends and composites. Both the presence of M3 wax and WF influenced the viscoelastic behavior of HDPE. The HDPE/M3 wax blends showed an increase in the interfacial amorphous content as the wax content increases, which resulted in the appearance of a ,-relaxation peak. The presence of M3 wax in HDPE reduced the mechanical properties of the blends. For the composites these properties varied with WF content. An increase in wax content resulted to a decrease in water uptake by the composites, probably because the wax covered the WF particles and penetrated the pores in these particles. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Nanostructure and micromechanical properties of reversibly crosslinked isotactic polypropylene/clay compositesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010S. Bouhelal Abstract Recent developments concerning the methodology used to prepare composites of iPP and nanoclays are reported. Conventional (reactive melt mixing) and in situ preparations were performed, and the structural properties exhibited by the composites are discussed. Results suggest that the nanoclay could exhibit partial and, maybe, total exfoliation within the composites. Adhesion between the polymeric matrix and the nanoclay layers is similar to that obtained after grafting. The experimental procedure used and the analysis performed by means of the wide-angle X-ray scattering and differential scanning calorimetry techniques permit to describe, at nanoscale level, the contribution of the nanoclay to the polymer composite system. The microhardness values of the iPP,clay composites depend on the clay content and on the preparation method, and linearly correlate, according to the additivity law, with the degree of crystallinity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Preparation of poly(acrylonitrile,butadiene,styrene)/montmorillonite nanocomposites and degradation studies during extrusion reprocessingJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2009E.-K. Karahaliou Abstract In this study, the preparation of organically modified montmorillonite/poly(acrylonitrile,butadiene,styrene) (ABS) nanocomposites was studied by melt blending in a twin-screw extruder. The composite material was subjected to a series of five extrusion cycles, and the effect of reprocessing on the material's structural properties was investigated. More specifically, chemical changes were studied with attenuated total reflectance/Fourier transform infrared analysis, the thermal response was recorded by differential scanning calorimetry experiments, and the thermal stability was detected with thermogravimetric analysis. Also, the rheological properties of these blends were investigated via melt flow index tests as a measure of their processability during melt mixing and molding processes. Furthermore, the mechanical strength of the obtained mixtures was explored, and the observed interactions were interpreted in terms of the influence of each component on the functional properties of the final mixture. This attempt enriched our knowledge about the recycling of ABS, with the additional aspect of the use of collected data from more complex systems, that is, composite materials, where the montmorillonite nanoparticles play a role in the interactions initiated by repeated processing. The experimental results of this study show that the reprocessing of ABS/montmorillonite induced oxidation products, but the rheological, mechanical, and thermal properties and the thermal and color stabilities of the composites remained almost stable. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Radiopaque, barium sulfate-filled biomedical compounds of a poly(ether-block-amide) copolymerJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Xiaoping Guo Abstract Various radiopaque compounds of a poly (ether- block -amide) copolymer resin filled with fine barium sulfate particles were prepared by melt mixing. Material properties of the filled compounds were investigated using various material characterization techniques, including thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic rheometry, uniaxial tensile test, and dynamic mechanical thermal analysis (DMTA). The effects of the filler and its concentration on the measured material properties are evaluated. It has been found that in addition to its well-known X-ray radiopacity, the filler is quite effective in reinforcing some mechanical properties of the copolymer, including modulus of elasticity and yield strength. More interestingly, it has been observed that at low loading concentrations near 10 wt %, the filler may also act as a rigid, inorganic toughener for the copolymer by improving the postyield material extensibility of strain hardening against ultimate material fracture. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Poly(lactic acid)-based biocomposites reinforced with kenaf fibersJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Maurizio Avella Abstract Biodegradable thermoplastic-based composites reinforced with kenaf fibers were prepared and characterized. Poly(lactic acid) (PLA) was selected as polymeric matrix. To improve PLA/fibers adhesion, low amount of a proper reactive coupling agent, obtained by grafting maleic anhydride onto PLA, was added during matrix/fibers melt mixing. Compared with uncompatibilized composites, this compatibilization strategy induces a strong interfacial adhesion and a pronounced improvement of the mechanical properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Correlation of morphology, rheology, and performance improvement in gasoline tubes based on PA-6 nanocompositesJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 3 2010Mehdi Moghri PA-6/organo-modified layered silicate nanocompounds were prepared by the melt mixing of PA-6 with different nanoclay loadings in a corotating twin-screw extruder. Gasoline tubes based on these nanocompounds were produced at different silicate loadings. Thermal, mechanical, rheological, and barrier properties of the different samples were investigated and correlated to their morphology. Transmission electron microscopy, wide angle X-ray scattering, and linear melt state viscoelastic measurements were used to characterize the different aspects of nanoclay dispersion in the nanocomposite samples. While tensile modulus, softening point, heat distortion temperature, and gasoline barrier properties of the prepared tubes were improved considerably by increasing the clay content, performance improvement with respect to clay content (after a certain value) decreased with increasing clay loading. It could be attributed to the re-agglomeration of tactoids at higher concentrations. These findings were correlated with the rheological and morphological observations. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers [source] Evaluation of the Effectiveness of New Compatibilizers Based on EBAGMA-LDPE and EBAGMA-PET Masterbatches for LDPE/PET BlendsMACROMOLECULAR MATERIALS & ENGINEERING, Issue 3 2010Aida Benhamida Abstract The present paper is aimed to evaluate the efficiency of two masterbatches, i.e., EBAGMA/LDPE (MB1) and EBAGMA/PET (MB2) with 50/50 w/w composition, prepared by melt mixing and used as new compatibilizers for blends of LDPE/PET. The morphology, the mechanical and the thermal properties of LDPE/PET/MB1 and LDPE/PET/MB2 ternary blends have been investigated. Morphological investigation by SEM of LDPE/PET/MB1 ternary blends showed a finer dispersion of PET in LDPE matrix with a better interfacial adhesion compared to those of both LDPE/PET/MB2 and binary LDPE/PET blends. The results also indicated a substantial improvement in both elongation at break and impact strength, while the Young's modulus decreased. Moreover, the thermal properties showed a decrease of the crystallization phenomena of PET in LDPE/PET/MB1 blend, thus confirming the good dispersion of PET particles into the continuous phase of LDPE matrix, leading to the conclusion that MB1 could be an efficient compatibilizer for LDPE/PET system. [source] Compatibilization of Polyamide-6/Polyarylate Blends by Means of an IonomerMACROMOLECULAR MATERIALS & ENGINEERING, Issue 8 2005Aritz Retolaza Abstract Summary: Polyamide-6 (PA6)/polyarylate of bisphenol A (PAr) blends rich in PA6 and modified with an additional 15% poly[ethylene- co -(methacrylic acid)] partially neutralized with zinc (PEMA-Zn) as a compatibilizer were obtained by melt mixing. Their phase structure, morphology, and mechanical performance were compared with those of the corresponding binary blends. The ternary blends were composed of a PA6 amorphous matrix and a dispersed PAr-rich phase in which reacted PA6 and PEMA-Zn were present. Additionally, minor amounts of a crystalline PA6 phase, and a PEMA-Zn phase were also present. The chemical reactions observed led to a clear decrease in the dispersed particle size when PEMA-Zn was added, indicating compatibilization. Consequently, the mechanical behavior of the blends with PEMA-Zn improved, leading, mainly in the case of the blend with 10% PAr, to significant increases in both ductility and impact strength with respect to those of the binary blends. These increases were more remarkable than the slight decrease in stiffness as a consequence of the rubbery nature of the compatibilizer. Cryogenically fractured surface of the PA6/PAr-PEMA-Zn 70/30-15 ternary blend. [source] Co-continuous Polyamide 6 (PA6)/Acrylonitrile-Butadiene-Styrene (ABS) NanocompositesMACROMOLECULAR RAPID COMMUNICATIONS, Issue 9 2005Yongjin Li Abstract Summary: Polyamide 6 (PA6)/acrylonitrile-butadiene-styrene (ABS) (40/60 w/w) nanocomposites with a novel morphology were prepared by the melt mixing of PA6, ABS and organoclay. The blend nanocomposites had a co-continuous structure, in which both PA6 and styrene-acrylonitrile (SAN) were continuous phases. It was found that the toughening rubber particles were only located in the SAN phase and the strengthening clay platelets were selectively dispersed in the PA6 phase. The co-continuous nanocomposites showed greatly improved mechanical properties over the whole temperature range when compared with the same blend sample without clay. Schematic diagram for the co-continuous ABS/PA6 blend nanocomposite. [source] An investigation on the correlation between rheology and morphology of nanocomposite foams based on low-density polyethylene and ethylene vinyl acetate blendsPOLYMER COMPOSITES, Issue 10 2010M. Riahinezhad This article presents the correlation between rheology and morphology of nanocomposite foams of low-density polyethylene (LDPE), ethylene vinyl acetate (EVA), and their blends. LDPE/EVA nanocomposites were prepared via melt mixing and then foamed using batch foaming method. To assess the rheological behavior of polymer melts, frequency sweep and creep recovery tests were done. Morphology of the samples was also studied by scanning electron microscopy and X-ray diffraction. The results showed that with increase in clay content, storage modulus, complex and zero shear viscosities will be increased, which affect the foam morphology. In addition, elasticity plays an important role in foaming process, in a way that samples with more elasticity percentage have the highest cell density and the lowest cell size. POLYM. COMPOS., 31:1808,1816, 2010. © 2010 Society of Plastics Engineers. [source] Structural properties and mechanical behavior of injection molded composites of polypropylene and sisal fiberPOLYMER COMPOSITES, Issue 3 2002X. L. Xie Composites based on isotactic polypropylene (PP) and sisal fiber (SF) were prepared by melt mixing and injection molding. The melt mixing characteristics, thermal properties, morphology, crystalline structure, and mechanical behavior of the PP/SF composites were systematically investigated. The results show that the PP/SF composites can be melt mixed and injection molded under similar conditions as the PP homo-polymer. For the composites with low sisal fiber content, the fibers act as sites for the nucleation of PP spherulites, and accelerate the crystallization rate and enhance the degree of crystallinity of PP. On the other hand, when the sisal fiber content is high, the fibers hinder the molecular chain motion of PP, and retard the crystallization. The inclusion of sisal fiber induces the formation of ,-form PP crystals in the PP/SF composites and produces little change in the inter-planar spacing corresponding to the various diffraction peaks of PP. The apparent crystal size as indicated by the several diffraction peaks such as L(110),, L(040),, L(130), and L(300), of the , and ,-form crystals tend to increase in the PP/SF composites considerably. These results lead to the increase in the melting temperature of PP. Moreover, the stiffness of the PP/SF composites is improved by the addition of sisal fibers, but their tensile strength decreases because of the poor interfacial bonding. The PP/SF composites are toughened by the sisal fibers due to the formation of ,-form PP crystals and the pull-out of sisal fibers from the PP matrix, both factors retard crack growth. [source] Influence of Ca[(Li1/3Nb2/3)0.8Ti0.2]O3-, filler on the microwave dielectric properties of polyethylene and polystyrene for microelectronic applicationsPOLYMER ENGINEERING & SCIENCE, Issue 3 2010Sumesh George Ceramic reinforced polyethylene and polystyrene composites were prepared by melt mixing and hot molding techniques. Temperature stable low-loss Ca[(Li1/3Nb2/3)0.8Ti0.2]O3-, (CLNT) ceramic was used as the filler to improve the dielectric properties of the polymers. The relative permittivity and dielectric loss in the microwave frequency range were increased with increase in the ceramic loading. As the filler content increased from 0 to 0.50 volume fraction, the relative permittivity increased from 2.3 to 9 and dielectric loss tangent from 0.0006 to 0.005 for polyethylene-CLNT composite. In the case of polystyrene-CLNT composite, the relative permittivity and dielectric loss tangent increased from 2.1 to 10.5 and 0.0005 to 0.0032 respectively with increase in filler content from 0 to 0.50 volume fractions. The thermal stability of the relative permittivity of polymer ceramic composites was also investigated. The experimentally observed relative permittivity was compared with theoretical models. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers [source] Crystallization and thermal behavior of multiwalled carbon nanotube/poly(butylenes terephthalate) compositesPOLYMER ENGINEERING & SCIENCE, Issue 6 2008Defeng Wu Multiwalled carbon nanotube/poly(butylene terephthalate) composites (PCTs) were prepared by melt mixing. The nonisothermal crystallization and thermal behavior of PCTs were respectively investigated by X-ray diffractometer, polarized optical microscope, differential scanning calorimeter, dynamic mechanical thermal analyzer, and thermogravimetric analyzer. The presence of nanotubes has two disparate effects on the crystallization of PBT: the nucleation effect promotes kinetics, while the impeding effect reduces the chain mobility and retards crystallization. The kinetics was then analyzed using Ozawa, Mo, Kissinger, Lauritzen-Hoffman, and Ziabicki model, and the results reveal that the nucleation effect is always the dominant role on the crystallization of PBT matrix. Thus the crystallizability increases with increase of nanotube loadings. In addition, the presence of nanotubes nearly has no remarkable contribution to thermal stability because nanotubes also play two disparate roles on the degradation of PBT matrix: the Lewis acid sites to facilitate decomposition and the physical hindrance to retard decomposition. Hence the nanotubes act merely as inert-like filler to thermal stability. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers [source] Nonuniformity of phase structure in immiscible polymer blendsPOLYMER ENGINEERING & SCIENCE, Issue 3 2008Ivan Fortelný This article is focused on the phase structure development in immiscible polymer blends during melt mixing. Nonuniformity of the phase structure, i.e., the coexistence of areas containing particles with markedly different size distribution, was detected in quenched and compression molded samples of a number of various blends prepared by long and intensive mixing in the chamber of a Plasticorder. The same effect was found also for polystyrene/polyamide blends prepared in a twin-screw extruder. It was shown that neglecting nonuniformity of the phase structure can lead to considerable error in evaluation of the effect of system parameters on the blend morphology. The reasons for the effect were discussed and it was found that inhomogeneous flow field in mixers is a plausible explanation of the nonuniform phase structure. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers [source] Barrier properties of blends based on liquid crystalline polymers and polyethylenePOLYMER ENGINEERING & SCIENCE, Issue 9 2000G. Flodberg Blends of an extrusion-grade polyethylene and two different liquid crystalline polymers of Vectra type were prepared by melt mixing using poly(ethylene-comethacrylic acid) as compatibilizer. Oxygen and water vapor permeability, transparency and welding strength of compression molded and film blown specimens were studied. The compression molded blends showed gas permeabilities conforming to the Maxwell equation assuming low permeability liquid crystalline polymer spheres in a high permeability polyethylene matrix. One of the liquid crystalline polymers with suitable rheological properties formed a more continuous phase in the film blown blends and a substantial decrease in oxygen and water vapor permeability was observed in these blends. The compression molded blends with 50% liquid crystalline polymer and some of blow molded blends showed very high gas permeabilities. It is believed that voids forming continuous paths through the structure were present in these samples. The blends showed significantly higher opacity than pure polyethylene. [source] Morphological and fractal studies of polypropylene/poly(ethene-1-octene) blends during melt mixing using scanning electron microscopyPOLYMER INTERNATIONAL, Issue 3 2008Xinhua Xu Abstract BACKGROUND: Polymer blending creates new materials with enhanced mechanical, chemical or optical properties, with the exact properties being determined by the type of morphology and the phase dimension of the blend. In order to control blend properties, morphology development during processing needs to be understood. The formation and evolution of polypropylene/poly(ethylene-1-octene) (PP/POE) blend morphology during blending are qualitatively represented by a series of time-dependent scanning electron microscopy (SEM) patterns. The area diameter and its distribution of dispersed phase domains are discussed in detail. In order to characterize the formation and evolution of phase morphology quantitatively, two fractal dimensions, Ds and Dd, and their corresponding scaling functions are introduced to analyze the SEM patterns. RESULTS: The evolution of the area diameter indicates that the major reduction in phase domain size occurs during the initial stage of melt mixing, and the domain sizes show an increasing trend due to coalescence with increasing mixing times. The distribution in dispersed phase dimension obeys a log-normal distribution, and the two fractal dimensions are effective to describe the phase morphology: Ds for dispersed phase dimension and Dd for the distribution in it. CONCLUSIONS: The fractal dimensions Ds and Dd can be used quantitatively to characterize the evolutional self-similarity of phase morphology and the competition of breakup and coalescence of dispersed phase domains. It is shown that the fractal dimensions and scaling laws are useful to describe the phase morphology development at various mixing times to a certain extent. Copyright © 2007 Society of Chemical Industry [source] | ||||||||||