Influence Of Blend Composition Research Articles

Fatigue behavior of polymethyl methacrylate/acrylonitrile butadiene styrene blends including blend composition, stress ratio, frequency, and holding pressure effects

In engineering applications, polymer materials are expected to exhibit superior fatigue life and balanced mechanical properties as essential performance criteria. The blending method is an important alternative in improving the performance criteria of ABS polymer in service. Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), and Dynamic Mechanical Analysis (DMA) methods were used for characterization. The effects of the PMMA fraction on the mechanical and fatigue behavior of PMMA/ABS blends were investigated by tensile and fatigue tests. Also, the influence of blend composition, stress amplitudes, stress ratio, holding pressure, and loading frequency on fatigue life is considered. The study improved yield strength, tensile strength, and elongation at break values of blends compared to ABS. In addition, 115 % and 75 % improvements were achieved in fatigue cycles at high and low-stress amplitudes with blends, respectively, for tension/tension loading. Similar improvements were obtained for fully reverse loading at 218 %. Thus, it was determined that the PMMA/ABS blend exhibited superior fatigue life in both tension/tension and fully reverse loading situations. Finally, it has been understood that PMMA/ABS blends can be designed to have mechanical properties and fatigue life behavior that can meet different requirements in conditions for engineering applications.

Modification of asphalt binder by the blend of chemically grafted thermoplastics and SBS: Influence of blend composition, chemical grafting, sulphur content, and MFI value

Modification of asphalt binder by the blend of chemically grafted thermoplastics and SBS: Influence of blend composition, chemical grafting, sulphur content, and MFI value

Influence of blend composition and annealing temperature on optical properties of organic photovoltaic cell based on P3HT:PCBM interpenetrating blend

ABSTRACTIn this paper, the influence of blend composition and annealing temperature on optical properties of organic photovoltaic (OPV) cells based on P3HT:PCBM interpenetrating blend is presented. Optical optimization of the OPV cell is first performed to determine the optimal geometry of the stack. The studied device structure is: glass/ITO/PEDOT:PSS/P3HT:PCBM/Ca/Al. Simulation results give as optimized thicknesses: dPEDOT:PSS = 27 nm and dActive layer = 91 nm. The optimized OVP cell gives a short-circuit current JSC = 12.48 mA/cm2. The influence of technological parameters on the performance of the optimized P3HT:PCBM blend OPV cell is then clearly defined. Simulation results show that among the mass ratio of P3HT:PCBM blend active layers studied (1:1, 1:2, 2:1, 2:3 and 3:2), the active layer with the higher blend mass ratio (2:1) gives the best optical properties. Also, increasing the annealing temperature of the active layer leads to increase absorption. The blend active layer annealed at 140°C presents the best optical properties of the OPV cell.

Controlling Processing, Morphology, and Mechanical Performance in Blends of Polylactide and Thermotropic Polyesters.

Thermoplastic composites based on thermotropic liquid crystalline polymer (LCP) materials are interesting candidates for reinforced composite application due to their promising mechanical performance and potential for recyclability. In combination with a societal push toward the more sustainable use of materials, these properties warrant new interest in this class of composites. Though numerous studies have been performed in the past, a coherent set of design rules for LCP design for the generation of injection-molded reinforced thermoplastic composites is not yet available, likely due to the complex interplay between LCP and matrix components. In this study, we report on the processing of poly(l-lactide) with two different LCPs, at relatively low processing temperatures. The study focuses on critical parameters for the morphological development and mechanical performance of LCP-reinforced composites. The influence of blend composition and the processing conditions, on the mechanical response of the composites, is investigated using rheology, wide-angle X-ray diffraction, mechanical analysis, and microscopy techniques. The study conclusively demonstrates that both the matrix viscosity and viscosity ratio between the dispersed and matrix phase, determine the deformation and breakup of the dispersed LCP droplets during extrusion. In addition, the thermal dependence of the viscosity ratio appears to be a critical parameter for the composite performance after injection molding. For example, during injection molding, stretching and molecular orientation of the LCP phase into highly oriented fibrils are prevented when the viscosity ratio increases rapidly upon cooling. In contrast, melt drawing proves to be a more effective processing route as the extensional flow field stabilizes elongated droplets, independent of the viscosity ratio. Overall, these findings provide valuable insights in the morphological development of LCP-reinforced blends, highlighting the importance of the development of viscoelastic properties as a function of temperature, and provide guidelines for the design of new LCP polymers and their thermoplastic composites.

Influence of Blend Composition and Silica Nanoparticles on the Morphology and Gas Separation Performance of PU/PVA Blend Membranes.

Polymer blending and mixed-matrix membranes are well-known modification techniques for tuning the gas separation properties of polymer membranes. Here, we studied the gas separation performance of mixed-matrix membranes (MMMs) based on the polyurethane/poly(vinyl alcohol) (PU/PVA) blend containing silica nanoparticles. Pure (CO2, CH4, N2, O2) and mixed-gas (CO2/N2 and CO2/CH4) permeability experiments were carried out at 10 bar and 35 °C. Poly(vinyl alcohol) (PVA) with a molecular weight of 200 kDa (PVA200) was blended with polyurethane (PU) to increase the CO2 solubility, while the addition of silica particles to the PU/PVA blend membranes augmented the CO2 separation performance. The SEM images of the membranes showed that the miscibility of the blend improved by increasing the PVA contents. The membrane containing 10 wt % of PVA200 (PU/PVA200–10) exhibited the highest CO2/N2~32.6 and CO2/CH4~9.5 selectivities among other blend compositions, which increased to 45.1 and 15.2 by incorporating 20 wt % nano-silica particles.

The influence of blend composition and filler on the microstructure, crystallization, and mechanical behavior of polymer blends with multilayered structures

The preparation of multilayered structures has been thought as a complicated process until our recent study illustrating an effective method through high speed thin wall injection molding (HSTWIM) of polypropylene (PP) and polyethylene (PE) based blends. Current study investigates the effect of blends composition as well as the addition of carbon nanotubes (CNT) on the structure and properties of these blends. It is observed that a close ratio of high density polyethylene (HDPE) and impact copolymer polypropylene (ICP) triggers the formation of a multilayered structure. Meanwhile, PE is migrated into the rubber phase in ICP, leading to the distribution of some rubber phase on the interface between PP and PE, which is thought as beneficial for the interfacial interaction. Meanwhile, epitaxial growth of PE crystals on PP substrate is also observed. The presence of rubber phase on the interface, multilayered structure and epitaxial growth of PE crystals on PP are thought to be responsible for the observed mechanical enhancement in tensile strength as well as strain at break. Furthermore, the addition of CNTs leads to enhanced strength, reduced strain at break and anisotropic conductive network.

Influence of blend composition and organic cloisite 15A content in the structure of isobutylene–isoprene rubber/ethylene propylene diene monomer composites for investigation of morphology and mechanical properties

A melt mixing method was used for preparation of immiscible isobutylene–isoprene rubber/ethylene propylene diene monomer blends and their polymer nanocomposites containing cloisite 15A nanoparticles. The morphology of nanocomposites was characterized by Fourier transform infrared spectroscopy and scanning electron microscope techniques. The dispersion of nanoclay in isobutylene–isoprene rubber/ethylene propylene diene monomer blends was studied by transmission electron microscopy and XRD analyses. Curing data of the prepared nanocomposites showed a decrease in scorch time (t5) and optimum cure time (t90) with increasing nanoclay content. Intercalation of rubber chains into the organoclay silicate layers was specified by d-spacing amount estimated according to the XRD results. Based on XRD results, a leftward shift towards lower diffraction angles in the organoclay characteristic peak was observed, indicating an increase in the d-spacing values in comparison with the pure organoclay. It confirms the intercalation of elastomer chains into the nanoclay galleries. The mechanical properties of the polymer nanocomposite specimens including hardness, fatigue strength, elongation at break, modulus and tensile strength were found to be better with increasing the nanoclay content. Also, resilience of the polymer nanocomposites decreased.

Miscibility and physical properties of chitosan and polyacrylamide blends

Miscibility studies of chitosan/polyacrylamide (Ch/PAM) and chitosan/partially hydrolyzed polyacrylamide (Ch/HPAM) blends of different compositions were investigated using viscometric method. The intrinsic viscosity, ([η]), and the viscosity interaction parameters, (bm), have been determined for the binary (solvent/polymer) and ternary (solvent/polymer A/polymer B) systems. Degree of miscibility of these polymer blends was estimated on the basis of two criteria. These studies indicate that chitosan/polyacrylamide and chitosan/partially hydrolyzed polyacrylamide are miscible at any composition in 0.1mol·dm−3 CH3COOH+0.2mol·dm−3 NaCl at 25°C. The influence of blend composition on mechanical properties was also investigated in this study. Ch, PAM, HPAM and their blend films were prepared by casting technique. The mechanical properties such as ultimate tensile strength and Young modulus depend on the weight fraction of chitosan and were changed irregularly. The FTIR spectroscopy also supports the obtained results. The miscibility of polymer mixtures is related to the interactions between the functional groups of the polymeric components.

Analysis of the electrical and optical properties of PEDOT:PSS/PVA blends for low-cost and high-performance organic electronic and optoelectronic devices

In this study we propose the use of a blend, comprising poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and polyvinyl alcohol (PVA), to be used as flexible, semitransparent and highly conductive material for electronic and optoelectronic devices. The electrical conductivity and optical transmittance of spray-deposited films of the blend, in different thicknesses and at different weight ratios, were studied in order to determine the most appropriate composition for optimal device performance and cost. We propose a direct method to determine the most appropriate blend composition to produce polymeric films with a desired sheet resistance, optical transmittance and cost, by using a diagram which considers the influence of blend composition and film thickness in a light-transmittance versus sheet resistance plot, mediated by the material cost per unit area. In this way, the present study establishes an empirical method to determine the PEDOT:PSS/PVA blend composition to be used as electrode material in optoelectronic devices which satisfies the desired conditions of optical transmittance, sheet resistance and cost-effectiveness.

Design and characterization of biocompatible shape memory polymer (SMP) blend foams with a dynamic porous structure

This study presents a comprehensive morphological, physical, and shape memory characterization of biocompatible shape memory polymer (SMP) blend foams composed of thermoplastic polyurethane (TPU) and polylactic acid (PLA). The TPU/PLA blend compositions studied were 80/20, 65/35, and 50/50 in weight percentage. The influence of blend composition and processing conditions on the pore morphology of the foams were studied with the scanning electron microscope (SEM). The results showed that all the TPU/PLA compositions formed close-celled porous structures. A number of physical characteristics of the foams were characterized, including relative density, pore density, porosity, and average pore size. The shape memory properties of the porous structure formed in the foams were investigated. The 80/20 and 50/50 TPU/PLA blends, and neat TPU contained a dynamic porous structure that contracted uniformly upon shape recovery. The recovery of the pores in the neat TPU was captured with a CCD camera in real time and the recovery force of the 80/20 TPU/PLA blend was measured with a custom built force sensor. These shape memory polymer foams are currently under investigation for biomedical applications, such as gastro-retentive drug delivery systems and wound dressings.

Influence of ethylene–propylene–diene terpolymer addition on processing parameters, phase structure and thermal behaviour of polypropylene/low-density polyethylene blends

The influence of blend composition and ethylene–propylene–diene terpolymer (EPDM) content on the processing parameters, phase structure and thermal behaviour of polypropylene (PP) and low-density polyethylene (LDPE) blends was studied. Processing parameters of blends in twin-screw extruder were followed by output ( Q), torque (TQ) and back pressure ( p), and apparent viscosity as given by TQ/ Q and p/ Q ratios, while the thermal behaviour was measured using differential scanning calorimetry. Phase structure was investigated using scanning transmission electron microscopy (STEM). The degree of crystallinity ( χc) of PP phase decreased and χc of LDPE phase increased with higher LDPE content in blends with and without EPDM. STEM micrographs of EPDM compatibilized PP/LDPE blends of compositions 80/20 and 20/80 showed particulate morphology, whereas in the blends of compositions 60/40 and 40/60 the morphology was co-continuous. The EPDM compatibilizer was localized on the interface.

Influence of Blend Composition and Compatibilizer on Mechanical and Morphological Properties of Recycled HDPE/PET Blends

Polymer blends based on recycled high density polyethylene (rHDPE) and recycled poly(ethylene terephthalate) (rPET) with and without ethylene-glycidyl methacrylate copolymer (E-GMA) as compatibilizer were fabricated in a co-rotating twin screw extruder. The effects of rPET and compatibilizer content on the mechanical properties and morphological stability of rHDPE-rich blends were investigated. The rHDPE/rPET (75/25 wt/wt) blend compatibilized with 5 php (per 100 part of polymer) E-GMA showed an enhancement of about 7% - 26% in tensile properties and flexural strength as compared with those of the neat rHDPE. The strain at break showed a decreasing trend as the rPET content increased. The addition of E-GMA to the rHDPE/rPET blends was found to recover the blend toughness as well as improving the compatibility between HDPE and PET. In this study, the highest strain at break was obtained for the rHDPE/rPET blends at 75/25 (wt/wt) composition with E-GMA content of 5 php. FTIR and SEM analysis of the compatibilized blends confirmed the chemical interaction and improved interfacial bonding between the two phases.

Bio-renewable precursor fibers from lignin/polylactide blends for conversion to carbon fibers

Lignin, a highly aromatic biopolymer extracted as a coproduct of wood pulping, was investigated as a suitable precursor for carbon fibers. Lignin was chemically modified and blended with poly(lactic acid) (PLA) biopolymer before melt spinning into lignin fibers. The chemical modification of raw lignin involved butyration to form ester functional groups in place of polar hydroxyl (–OH) groups, which enhanced the miscibility of lignin with PLA. Fine fibers were extracted and spooled continuously from lignin/PLA blends with an overall lignin concentration of 75wt.%. The influence of chemical modification and physical blending of lignin with PLA on the resulting fiber was studied by analyzing the microstructure of the fibers using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The influence of blend composition on the phase behavior was studied by differential scanning calorimetry (DSC). The effect of composition on the mechanical properties was studied by tensile tests of the lignin/PLA blend fibers. The thermal stability and carbon yield of the blended fibers with different concentrations of lignin were characterized by thermogravimetric analysis (TGA). The microstructure analysis of carbon fibers produced from lignin/PLA blends revealed composition dependent microporous structures inside the fine fibers.

Fabrication, characterization and cellular compatibility of poly(hydroxy alkanoate) composite nanofibrous scaffolds for nerve tissue engineering.

Tissue engineering techniques using a combination of polymeric scaffolds and cells represent a promising approach for nerve regeneration. We fabricated electrospun scaffolds by blending of Poly (3-hydroxybutyrate) (PHB) and Poly (3-hydroxy butyrate-co-3- hydroxyvalerate) (PHBV) in different compositions in order to investigate their potential for the regeneration of the myelinic membrane. The thermal properties of the nanofibrous blends was analyzed by differential scanning calorimetry (DSC), which indicated that the melting and glass temperatures, and crystallization degree of the blends decreased as the PHBV weight ratio increased. Raman spectroscopy also revealed that the full width at half height of the band centered at 1725 cm−1 can be used to estimate the crystalline degree of the electrospun meshes. Random and aligned nanofibrous scaffolds were also fabricated by electrospinning of PHB and PHBV with or without type I collagen. The influence of blend composition, fiber alignment and collagen incorporation on Schwann cell (SCs) organization and function was investigated. SCs attached and proliferated over all scaffolds formulations up to 14 days. SCs grown on aligned PHB/PHBV/collagen fibers exhibited a bipolar morphology that oriented along the fiber direction, while SCs grown on the randomly oriented fibers had a multipolar morphology. Incorporation of collagen within nanofibers increased SCs proliferation on day 14, GDNF gene expression on day 7 and NGF secretion on day 6. The results of this study demonstrate that aligned PHB/PHBV electrospun nanofibers could find potential use as scaffolds for nerve tissue engineering applications and that the presence of type I collagen in the nanofibers improves cell differentiation.

Bioplastics from Blends of Cassava and Rice Flours: The Effect of Blend Composition

Abstract Bioplastics from melt-mixing of cassava flour, rice flour and their blends with compositions of between 0/100 and 100/0 %wt were successfully obtained using twin-screw extrusion and compression molding processes. The influence of blend composition on the bioplastic's properties was studied. It was found that the flour blends were uniformly mixed. The tensile properties and dynamic properties of the flour bioplastics were examined. The tensile strength and storage modulus of compression molded bioplastics based on rice flour was greater than those of the cassava flour, but their flexibility was lower. The tensile strength and storage modulus of the flour blend bioplastics increased with increasing rice flour content. The flour bioplastics showed two glass transitions, one corresponding to glycerol rich phase and the other corresponding to plasticized starch. For plasticized flour blends, the glass transitions were not affected by the blend composition. The improvement in the mechanical properties of the bioplastics produced from the cassava/rice flour blend could be explained by an increase in the crystallinity level resulting from the higher concentration of rice flour. Using flour blends derived from cassava and rice flours, the bioplastics developed in this study offer a greater performance while maintaining environmental compatibility and sustainability, which allows for a substitution of tradition bioplastics from cassava starch.

Effect of blend composition on crystallization behavior of polyoxymethylene/poly(ethylene oxide) crystalline/crystalline blends

The influence of blend composition on crystallization behavior of a typical crystalline/crystalline blend, polyoxymethylene (POM)/poly(ethylene oxide) (PEO), during slow non-isothermal crystallization was investigated by polarized light microscope (PLM) connected with a THMS600 hot-stage, scanning electron microscope (SEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The experimental results indicated that with increasing PEO content in the blend, the crystallization temperature of POM of the blends reduced and the multiple crystalline morphologies or structures including two kinds of interfibrillar or interlamellar structures were produced. The melting point of each component decreased with raising the content of the other constituent due to the inclusion and entanglement between POM and PEO molecules. The shoulder melting peak of POM appeared in DSC heating traces of the PEO-rich blend because the stronger inclusion and entanglement induced the imperfect crystallization of POM.

Influence of blend composition on mechanical properties of ASA/SAN binary blends

In this study, acrylonitrile–styrene–acrylic/styrene–acrylonitrile copolymer (ASA/SAN) binary blends with different compositions were prepared by mixing ASA and SAN by melt blending. Properties of the binary blends were studied by dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC), fourier transform infrared spectra (FTIR), heat distortion temperature (HDT), melt flow rate (MFR), mechanical properties and scanning electron microscopy (SEM), respectively. Since a grafted SAN shell is contained in ASA’s core shell structure, it is considered to have a good compatibility with SAN, and the results confirmed it. The binary blends showed a single glass transition temperature (Tg) according to DSC and DMTA measurements. Only weak interactions between the characteristic groups were obtained in FTIR spectrum. No obvious phase separation observed in SEM photographs indicated good compatibility between ASA and SAN. With respect to mechanical properties, impact strength and elongation at break of ASA/SAN blends decreased significantly with the SAN content but tensile strength, flexural strength and modulus increased. In addition, the incorporation of SAN enhanced the heat resistance and processability of the blend system.

Evaluation of Phase Morphology, Rheological, and Mechanical Properties Based on Polypropylene Toughened with Poly(ethylene-co-octene)

The influence of blend composition on phase morphology, rheological, and mechanical properties of polypropylene/poly(ethylene-co-octene) blends was studied. Phase morphology of the blends in the whole range of composition was examined using scanning electron microscope. The rheological data were analyzed to yield the variations of rheological properties and insight into the microstructure of PP/POE blends. The finite element code ANSYS was used for the analysis of the interfacial stress and its distribution between dispersed phase and matrix phase.

Real Space and Wave‐Number Space Studies of the Phase Structure and Morphology of iPP/PEOc Blends Using Scanning Electron Microscopy

AbstractThe influence of blend composition on the phase structure and morphology of poly(propylene)/poly(ethylene‐co‐octene) blends was studied using SEM. A diameter dg was defined and calculated in real space to discuss the phase structure and morphology of iPP/PEOc blends. The figure‐estimation method was introduced to determine the distribution width of dg. It was shown that the distribution of dg obeys a log‐normal distribution and the distribution width σ of dg was calculated. In wave‐number (h) space, the correlation distance, ac, was defined by applying light scattering theory to power spectrum images obtained by 2D Fourier transformation. Moreover, a fractal dimension, Dc, was introduced to describe the uniformity of the spatial distribution.magnified image

Influence of blend composition on the mechanical properties and morphology of PC/ASA/SAN ternary blends

Bisphenol A polycarbonate/acrylonitrile–styrene–acrylic/styrene–acrylonitrile copolymer (PC/ASA/SAN) ternary blends were prepared over a range of compositions via mixing PC, SAN, and ASA copolymer by melt blending. An analysis was made on the mechanical properties and morphology of the blends. Special care was taken to make comparisons of the morphologies and properties of blends with different SAN content. When a small amount SAN was introduced to PC/ASA blends, the dispersion condition of ASA in the matrix was improved and a better integrated mechanical properties was realized. Further increasing the SAN content led to a decrease of impact strength, which was due to the changing of the morphology of the blends and the inherent brittleness of matrix. The study about the effect of ASA content on the properties of PC/ASA/SAN blends showed that the blend with 20 wt% ASA had good mechanical properties.