Blend Constituents Research Articles

Influence of sequential melting and sintering process on morphology development and performance properties of ultra‐high molecular weight polyethylene/low‐density polyethylene blends

AbstractBlending ultra‐high molecular weight polyethylene (UHMWPE) with a low molecular weight polyolefin is a well‐established technique to improve its processability. The binary blends of UHMWPE and low‐density polyethylene (LDPE) were prepared with varying LDPE content (10%, 20%, 30%, 40%, and 50% by wt.) leading to the formation of a single polymer composite system (SPCS) as melting and sintering followed preferential stages during mixing. Interestingly, the sequence of either “melting followed by sintering” or “simultaneous sintering and melting” depends on the LDPE content in the blend, resulting in unique blend morphology. Separate melting peaks for the blend's constituents were observed in thermal characterization, showing the blend's immiscibility, while intermediate peaks showed moderate miscibility in the melt state. Due to the high entanglement density, UHMWPE retained a solid‐like structure and showed an intense viscous nature even above the melting point in rheological characterization. Typically, the UHMWPE samples are fabricated by boundary fusion between particles called sintering. At LDPE content higher than 30 wt.%, the sea island structure was visible in morphological analysis, and the preexisting cavities reduced the tensile modulus by 54% in the blend, along with decreased elongation at failure (250%–100%). Similarly, the flexural modulus was reduced by 34.7% in the blends, along with the decreased flexural strength. Interestingly, the decrease in performance properties occurred in two steps over the range of LDPE content. Thus, it was clear that 30 wt.% of LDPE in the UHMWPE/LDPE blend represented the critical concentration for controlling melting and sintering sequence to develop specified morphology and performance properties. These blends have the potential for biomedical application as well as for the development of foam products, which is the further scope of the present study.

Understanding charge transfer dynamics in blended positive electrodes for Li-ion batteries

This paper investigates the electrochemical behavior of binary blend electrodes comprising equivalent amounts of lithium-ion battery active materials, namely LiNi0.5Mn0.3Co0.2O2 (NMC), LiMn2O4 (LMO), LiFe0.35Mn0.65PO4 (LFMP) and LiFePO4 (LFP)), with a focus on decoupled electrochemical testing and operando X-ray diffraction (XRD). All possible 50:50 blend combinations were studied and the distribution of current between blend components was followed during continuous and pulsed charge and discharge processes. The results demonstrate the significant impact of the voltage profiles of individual materials on the current distribution, with the effective C-rate of each component varying throughout the State of Charge (SoC). Pulsed decoupled electrochemical testing reveals the exchange of charge between blend components during relaxation, showcasing the "buffer effect", which has also been captured through time-resolved operando XRD experiments in real blends carefully considering beam-induced effects. The directionality and magnitude of the charge transfer were found to depend on the nature of the components and the cell SoC, being also influenced by temperature. These dependencies can be rationalized considering both thermodynamics (voltage profile) and reaction kinetics of the blend constituents. These findings contribute to advancing the understanding of internal dynamics in blended electrodes, offering valuable insights for the rational design of blends to meet the diverse operational demands of lithium-ion batteries.

Fabrication of Triblock Elastomer Foams for Oil Absorption Applications: Effects of Crosslinking, Composition, and Rheology Factors

Oil spill accidents and oil-contaminated wastewater release from industries cause severe environmental pollution, resource waste, and economic loss. Thus, there is a dire need for an efficient oil/water separation approach to mitigate the challenge. Among the various oil/water separation technologies, employing oil-absorbing materials is one of the most effective strategies. In this work, a highly effective elastomer foam based on styrene–ethylene–butylene–styrene (SEBS) and ethylene propylene diene monomer (EPDM) blend was developed. Dicumyl peroxide was employed as a radical initiator for the crosslinking of the elastomer blend. The crosslinking of the blend significantly increased the melt strength of the SEBS/EPDM blend and therefore allowed them to expand extensively (up to 1200 vol %) with substantial volume increase (expansion ratio 12.8–13.1) and created pores with well-defined structures. As a result, the material exhibited outstanding oil absorption (up to 1030 wt %) due to an enlarged surface area and blend constituents. The incorporation of EPDM and radical-mediated crosslinking prevented the dissolution of SEBS in the oil and maintained the structural integrity of the foam in the oil, paving the way for recyclability. Also, the inherent hydrophobicity of employed polymers led to poor interaction with water and, thus, outstanding oil/water separation ability of the developed elastomer foams. Additionally, the foaming of triblock polymers, including SEBS, remained largely unexplored. This study has elucidated the impact of crosslinking and rheological factors on the successful foaming of SEBS.

Synergistic attraction of Western black-legged ticks, Ixodes pacificus, to CO2 and odorant emissions from deer-associated microbes.

Foraging ticks reportedly exploit diverse cues to locate their hosts. Here, we tested the hypothesis that host-seeking Western black-legged ticks, Ixodes pacificus, and black-legged ticks, I. scapularis, respond to microbes dwelling in sebaceous gland secretions of white-tailed deer, Odocoileus virginianus, the ticks' preferred host. Using sterile wet cotton swabs, microbes were collected from the pelage of a sedated deer near forehead, preorbital, tarsal, metatarsal and interdigital glands. Swabs were plated on agar, and isolated microbes were identified by 16S rRNA amplicon sequencing. Of 31 microbial isolates tested in still-air olfactometers, 10 microbes induced positive arrestment responses by ticks, whereas 10 others were deterrent. Of the 10 microbes prompting arrestment by ticks, four microbes-including Bacillus aryabhattai (isolates A4)-also attracted ticks in moving-air Y-tube olfactometers. All four of these microbes emitted carbon dioxide and ammonia as well as volatile blends with overlapping blend constituents. The headspace volatile extract (HVE) of B. aryabhattai (HVE-A4) synergistically enhanced the attraction of I. pacificus to CO2. A synthetic blend of HVE-A4 headspace volatiles in combination with CO2 synergistically attracted more ticks than CO2 alone. Future research should aim to develop a least complex host volatile blend that is attractive to diverse tick taxa.

Recycled fibers from pre- and post-consumer textile waste as blend constituents in manufacturing 100% cotton yarns in ring spinning: A sustainable and eco-friendly approach

The usage of recycled fibers has achieved enormous importance in the textile sector due to growing environmental awareness, legal requirements for more sustainability and the cost of raw materials. Recycled cotton fibers derived from mechanical shredding of textile waste possess lower quality values and therefore they are spun through blending with other fibers in rotor spinning system for the production of coarse yarns (10–20 Ne) to make denim, towel and home furnishing. Owing to low fiber migration, rotor yarns require high twist during spinning which makes them stiffer and poorly moisture absorbent. Rotor yarns also feel harsh in skin contact due to the presence of wrapper fibers in the yarn surface. Intending to make knit top garments like T-shirts and polo shirts, apparel manufacturers nowadays demand recycled fiber-contained soft and high moisture absorbent yarn that can be produced in ring spinning system. In the current endeavor, cotton fibers reclaimed from pre- and post-consumer textile waste were blended with virgin cotton and soft-twisted 30 Ne yarns were manufactured in ring spinning frame on an industrial scale in a spinning mill. A thorough analysis of the structure and properties of the yarns revealed that up to 25% recycled cotton fibers can be used as an alternative to virgin cotton to manufacture medium count (30 Ne) yarn in ring spinning suitable to produce knit top garments.

Study of polycarbonate–polystyrene interfaces using scanning transmission electron microscopy spectrum imaging (STEM‐SI)

AbstractPolymer blends are important for both commercial utility and scientific understanding. The degree of interfacial mixing in polymer blends is important since it influences the blends' mechanical properties. Understanding bulk properties in multiphase polymeric materials requires knowledge of the interfacial properties of the materials. The characterization of the interface, in terms of its width and composition profile, provides insight about the bulk behaviour of the material. Chemical microscopy through electron energy‐loss spectroscopy (EELS) in a transmission electron microscope is gaining popularity to characterize narrow polymer–polymer interfaces. In this work, we show how scanning transmission electron microscopy spectrum imaging, a spatially resolved energy‐loss spectroscopy, can be employed to calculate the interfacial width in a pair of immiscible polymers, taking a polycarbonate–polystyrene (PC‐PS) bilayer as an example. By mapping peaks unique to each of the blend constituents at several points across the interface, we show how the interfacial profile concentrations can be determined. With this method we calculated the interfacial width in the PC‐PS bilayer sample to be approximately 32 nm, even utilizing low resolution spectrometers, which are more widely available. Using the technique described with higher resolution EELS instruments having a better signal‐to‐noise ratio, a higher spatial resolution can be achieved. Using EELS chemical fingerprints of polymers that have been developed earlier, the technique presented here has the potential for effective visualization and morphological measurements of phase‐differentiated polymer blends. This paper is an attempt to enable a new user to characterize polymer–polymer interfaces using chemical microscopy. © 2022 Society of Industrial Chemistry.

Long term accelerated influence on thermo-mechanical properties of glass/carbon fiber reinforced interpenetrating polymer network hybrid composites

The prime importance of this work is that to compare the influence of hygrothermal analysis on the physical properties of different variant of interpenetrating polymer network (IPN) blend reinforced with E-Glass/Carbon and combination of both (hybrid) fibers. In this study, combinations of epoxy (EP)/polyurethane (PU), vinyl ester (VER)/polyurethane (PU), and epoxy (EP)/vinyl ester (VER) have been taken as the matrix material (IPN) to reinforce the glass, carbon, and combination of both fibers. Moreover, prepared specimens are subjected with boiling water immersion test by maintaining the temperature of 45°C, 55°C, and 65°C in order to thoroughly understand the influence of moisture absorption and temperature in their physical attribution as per ASTM standards. Besides, to better understand the thermal stability and compatibility, thermal-gravimetric (TGA) analysis and burn-off test were conducted as well. During this study, it was found that, combination of VER/PU possesses the high moisture absorption resistance amongst all variants (0.725% for 45°C, 0.854% for 55°C, 1.234 for 65°C). Similarly, epoxy/vinyl ester reinforced glass fiber IPN laminate (EVG) has shown notable TGA value as 418.6°C, as well burn-off test also shown that hybrid IPN composites have better wettability (less void presence) than all other laminates (EPGC-0.9%, VPGC-0.89%, EVGC-0.92%). Further, losses of physical strengths have been noticed on all specimens upon subjection on hygrothermal environment irrespective of IPN blend and fiber constituents.

Development of β-cyclodextrin/polyvinypyrrolidone-co-poly (2-acrylamide-2-methylpropane sulphonic acid) hybrid nanogels as nano-drug delivery carriers to enhance the solubility of Rosuvastatin: An in vitro and in vivo evaluation.

The present study is aimed at enhancing the solubility of rosuvastatin (RST) by designing betacyclodextrin/polyvinypyrrolidone-co-poly (2-acrylamide-2-methylpropane sulphonic acid) crosslinked hydrophilic nanogels in the presence of crosslinker methylene bisacrylamide through free-radical polymerization method. Various formulations were fabricated by blending different amounts of betacyclodextrin, polyvinylpyrrolidone, 2-acrylamide-2-methylpropane sulphonic acid, and methylene bisacrylamide. The developed chemically crosslinked nanogels were characterized by FTIR, SEM, PXRD, TGA, DSC, sol-gel analysis, zeta size, micromeritics properties, drug loading percentage, swelling, solubility, and release studies. The FTIR spectrum depicts the leading peaks of resultant functional groups of blended constituents while a fluffy and porous structure was observed through SEM images. Remarkable reduction in crystallinity of RST in developed nanogels revealed by PXRD. TGA and DSC demonstrate the good thermal stability of nanogels. The size analysis depicts the particle size of the developed nanogels in the range of 178.5 ±3.14 nm. Drug loading percentage, swelling, solubility, and release studies revealed high drug loading, solubilization, swelling, and drug release patterns at 6.8 pH paralleled to 1.2 pH. In vivo experiments on developed nanogels in comparison to marketed brands were examined and better results regarding pharmacokinetic parameters were observed. The compatibility and non-toxicity of fabricated nanogels to biological systems was supported by a toxicity study that was conducted on rabbits. Efficient fabrication, excellent physicochemical properties, improved dissolution, high solubilization, and nontoxic nanogels might be a capable approach for the oral administration of poorly water-soluble drugs.

Synergistic effects of soap nut extract and glutaraldehyde on the properties of natural rubber: A waste to wealth approach

This study aimed at the extraction of soap nut fruit to blend with natural rubber as a natural additive. The effectiveness of blending at various blend ratios has been studied in detail. The effects of soap nut extract on the tensile properties, thermal stability, glass transition and crystalline melting temperatures, solvent transport properties, morphology and antibacterial properties were investigated. FTIR was employed to confirm the presence of functional groups and the interaction between both the blend constituents. Enhancement in the tensile and thermal properties of natural rubber was noticed upon the incorporation of soap nut extract. The increased glass transition and crystalline melting temperatures suggests the miscibility of both blend components. Solvent transport study in benzene showed an increasing trend upon the addition of soap nut extract into natural rubber. SEM microphotographs showed a fine and continuous surface morphology in case of the blend when compared to pure natural rubber. Antibacterial studies revealed that the incorporation of soap nut extract makes natural rubber more stable. The blend with 5 % soap nut extract exhibited superior properties than that of the other blend components.

Multidimensional Mass Spectrometry of Multicomponent Nonionic Surfactant Blends.

Ultraperformance liquid chromatography (UPLC) and ion mobility (IM) spectrometry were interfaced with mass spectrometry (MS) and tandem mass spectrometry (MS/MS) to characterize a complex nonionic surfactant mixture. The surfactant was composed of a glycerol core, functionalized with poly(ethylene oxide) units (PEOn) that were partially esterified by caprylic and/or capric acid. Reversed-phase UPLC classified the blend based on polarity into four groups of eluates, corresponding to compounds with zero, one, two, or three fatty acid residues. Additional separation within each eluate group was achieved according to the length of the fatty acid chains. Coeluting molecules of similar polarity were dispersed in the gas phase by their collision cross section in the IM dimension. Performed in series, UPLC and IM allowed for the separation and detection of several isomeric and isobaric blend constituents, thereby enabling their isolation for conclusive MS/MS analysis to confirm or elucidate their primary structures and architectures (overall four-dimensional, 4D, characterization).

Non-destructive depth-dependent morphological characterization of ferroelectric:semiconducting polymer blend films

Herein, we investigate the technologically relevant blend of the ferroelectric polymer poly(vinylidene fluoride-co-trifluoroethylene), P(VDF-co-TrFE), with the semiconducting polymer poly(3-hexylthiophene), P3HT, by means of a combination of scanning probe microscopy techniques, namely atomic force microscopy, conductive force microscopy, kelvin probe force microscopy, and piezoresponse force microscopy. This combination proves to be a powerful tool for the non-destructive morphological reconstruction of multi-functional nano-structured thin films, as those under study. Each modality allows discerning the two blend constituents based on their functionality, and, additionally, probes layers of different thickness with respect to the film surface. The depth-dependent information that is collected allows a qualitative reconstruction of the blend’s composition and morphology both in-plane and out-of-plane of the film. We demonstrate that P3HT exhibits the tendency to reside the film surface at an almost constant composition of 15%, independent of blend’s composition. Increasing the P3HT content in the blend results in the segregation of P3HT at the upper layers of the films, partially buried below a P(VDF-co-TrFE) superficial layer. The depletion of P3HT from the substrate/film interface is reflected by the poor existence of conducting pathways that connect the top and bottom planes of the film. The three-dimensional morphology of this polymer blend that is revealed thanks to the employed techniques deviates substantially from the ideal morphology proposed for the efficient performance of the targeted memory devices.

Thermoplastic starch and poly(vinyl alcohol) blends centered barrier film for food packaging applications

This study explores the potential use of a Thermoplastic Starch (TPS)/Polyvinyl Alcohol (PVOH) blend as an alternative center-layer material to ethylene vinyl alcohol (EVOH) in food packaging films. Multi-layer films consisting of a TPS/PVOH blend center-layer sandwiched between low-density polyethylene (LDPE) outer layers were prepared in a co-extruded blown film line. Middle-layer blend concentration of TPS was varied from 0 to 100 wt% and the barrier and mechanical properties were characterized. Films with center layer blends containing 25 and 75 wt% TPS exhibited similar oxygen barrier properties to neat EVOH. Moreover, multi-layer films containing 25 wt% TPS center-layers showed the highest tensile strength and dart impact value among all blends and this was attributed to an enhanced interaction between blend constituents. The study suggests that the blends containing either 25 or 75 wt% TPS could serve as alternative barrier layers due to their relatively low material cost, good oxygen barrier performance and adequate material properties.

Separation of emulsified oil from wastewater using polystyrene and surfactant modified sugarcane bagasse wastes blend

A recent trend for converting a hydrophilic lignocellulosic material into oleophilic adsorbent could be achieved by using cationic surfactants. In the present work, the surface of sugarcane bagasse was modified by cationic surfactant cetyltrimethylammonium bromide, whereas sugarcane bagasse acquired hydrophobic properties. Further increase in hydrophobicity of sugarcane bagasse could be obtained by blending surfactant modified sugarcane bagasse with polystyrene waste. Sugarcane bagasse, surfactant modified bagasse and polystyrene waste/surfactant modified bagasse were characterized by different physical and chemical techniques. Remarkable changes in the structure of sugarcane bagasse as a result of the different treatment processes could be evidenced by FT-IR, SEM and XRD measurements. Moreover, elemental analysis, specific surface area as well as water absorption capacity results confirmed successful modification of sugarcane bagasse by both cetyltrimethylammonium bromide and polystyrene waste. Also, water absorption capacity experiments indicated that hydrophobic properties of the different samples increased in the order: polystyrene waste/surfactant modified bagasse > surfactant modified bagasse > sugarcane bagasse. The different samples were evaluated for removal of emulsified food oil from aqueous solutions. The effect of various parameters, e.g., blend constituents weight ratio, adsorbent dose, initial oil concentration, pH and contact time upon oil removal efficiency, was investigated. Isothermal studies revealed that oil adsorption fitted Freundlich model and thermodynamics studies showed that oil adsorption is spontaneous, random and exothermic.

Rheological rationalization of in situ nanofibrillar structure development: Tailoring of nanohybrid shish-kebab superstructures of poly (lactic acid) crystalline phase

The key rheological parameters for in situ development of poly (butylene terephthalate) nanofibrils (PBT NFs) in poly (lactic acid) (PLA) matrix using a tuned melt spinning process were studied. Observation of ellipsoidal PBT domains oriented along a short die was attributed to a low interfacial tension between the blend constituents and fulfilled melt rheological criteria for fibrillation in a simple shear flow. The stability of the deformed droplets under the shear and elongational flows was studied by comparing the droplet breakup time and residence time in each flow field. It was demonstrated that the deformed droplets (ellipses) with an increased robust interface underwent coalescence through pinch-off in the subsequent elongational flow field, and transformed to the nanofibrils with an average diameter comparable to the gyration radius (Rg) of PLA chains. In the fabricated isotropic in situ nanofibrillar composites (NFCs), a random orientation of 2D nanohybrid shish-kebab (NHSK) superstructure was observed as a result of the orthogonal pattern of melt crystallized PLA nanodomains on the PBT NFs surface. The NHSK superstructure established in quiescent bulk through mechanism of geometric confinement (soft epitaxy) enabled us to tailor the crystalline morphology via annealing temperature. In a constant nanofibril content, increasing the isothermal temperature (Tiso) up to 114 °C led to an increase in the kebabs length and interlocking of the adjacent superstructures. A transition to spherulitic crystal morphology was observed due to further temperature increase (Tiso≥117 °C). The observed transition indicated that at higher Tiso, the fewer raw nuclei, which were initiated by soft epitaxy mechanism of PLA chain segments on the PBT NFs at the early stage of nucleation, could conduct self-nucleation and 3D lateral growth. The Avrami model was found to be applicable for interpreting variations of crystallite morphology, crystallization rate, and nucleation mechanisms with PBT NF content and isotherm temperature.

Shock-induced ignition and pyrolysis of high-pressure methane and natural gas mixtures

A high-pressure shock tube was used to study ignition delay times (IDT) of CH4/O2/Ar and natural gas/O2/Ar mixtures behind reflected shock waves. Reaction progress was monitored using sidewall pressure and direct laser absorption diagnostics of CH4 near 3.175 µm and ethylene near 10.532 µm. Stoichiometric, fuel-rich and fuel-lean mixtures of CH4/O2, highly dilute in argon, were studied over a temperature range from 1450 to 1850 K and pressures between 10 and 55 atm. Of note are the experiments conducted with fuel-rich mixtures, as there is a lack of literature data in this regime. In the current study, the methane absorption diagnostic provided a unique tool enabling both speciation of methane and a clear definition of ignition delay time. In addition to methane oxidation, we have measured ignition delay times of commercial natural gas blends over a temperature range of 1408–1541 K, at pressures near 12 atm, and at an equivalence ratio of 1. To understand the effects of minor constituents (such as ethane and propane) in commercial natural gas blends, ethylene concentration during pyrolysis experiments was monitored using a two-wavelength scheme (10.532 µm and 10.674 µm) using a CO2 gas laser. The deficiency of existing kinetic models towards predicting the high-temperature kinetics of natural gas blends was highlighted through our measurements. Therefore, this study also provides data critical for refining these models. Extensive sensitivity analysis emphasizes the importance of the reaction CH3+C2H6→CH4+C2H5 during natural gas pyrolysis, and the accuracy of the chemical kinetic models is significantly improved by using a revised reaction rate constant (Shao et al. 2019) for this reaction. These measurements extend the test conditions of earlier studies of methane and commercial natural gas.

The contribution of lignocellulosic constituents to Cr(VI) reduction capacity of biochar-supported zerovalent iron

Biochars (BCs) derived from individual and blending lignocellulosic constituents were prepared to harbor zerovalent iron (ZVI/BC) in an effort to discriminate significance of each constituent or combination in ZVI/BC for Cr(VI) removal. BCs and ZVI/BC were characterized by TGA/GSC, XRD, Raman and BET analyses. Cellulose (BCC) and hemicellulose (BCH)-derived BCs has greater C content, H/C ratio, surface area and mass loss than BCs derived from lignin or lignin-containing biopolymer blends (BCLX). As per sorption and XPS analysis, ZVI/BC demonstrated greater Cr(VI) removal capacity than respective BCs, in which reduction accounted for over 77% Cr(VI) detoxification. Cr(VI) reduction by ZVI harbored by BCC and BCH was 19.72–16.54 g kg−1, compared to 5.97–4.26 g kg−1 for BCLX. ZVI/BC prepared by three-biopolymer blends with (12.63 g kg−1) or without (12.32 g kg−1) mineral approximated pinewood-BC (BCP) (13.02 g kg−1) for Cr(VI) reduction, suggesting minerals are not important constituent. Tafel analysis showed BCC and BCH, with lower ID/IG ratio owing to greater graphitization, were more conducible to transfer electron of ZVI in Cr(VI) reduction than BCLX. Thus, cellulose, hemicellulose and lignin can offer a good prediction of property of natural biomass, in which BCC and BCH favor electron transfer of ZVI but BCL is not electroactive.

Effect of Tacticity on the Phase Behavior and Demixing of PαMSAN/dPMMA Blends Investigated by SANS

We investigate the effect of polymer tacticity on the phase behavior and phase separation of polymer mixtures by small-angle neutron scattering (SANS). Poly(α-methyl styrene-co-acrylonitrile) (PαMSAN) and deuterated poly(methyl methacrylate) (dPMMA) with two degrees of syndiotacticity were selected as a model partially miscible blend, as one of the most highly interacting systems known (defined by the temperature dependence of the blend’s interaction parameter). One-phase (equilibrium) and time-resolved, spinodal demixing experiments were analyzed by de Gennes’ random phase approximation (RPA) and Cahn–Hilliard–Cook (CHC) theory, respectively. The second derivative of the Gibbs free energy of mixing with respect to composition (G″ ≡ ∂2ΔGm/∂ϕ2) and corresponding χ parameter were obtained from both RPA and CHC analysis and found to correlate well across the phase boundary. We find that blends with higher PMMA syndiotacticity exhibit greater miscibility and a steeper G″ temperature dependence by ∼40%. The segment length of dPMMA with higher syndiotacticity was found to be a = 7.4 Å, slightly larger than 6.9 Å reported for lower syndiotacticity dPMMA. Consideration of thermal fluctuations is required for the self-consistent analysis of the nontrivial evolution of the spinodal peak position q* over time, corroborated by CHC model calculations. The temperature dependence of the mobility parameter, M, can be described by a “fast-mode” average of the diffusion coefficients of the blend constituents, except for quenches originating near the glass transition. A minimum demixing length scale of Λ ≈ 40 nm is obtained, in agreement with the theory for deeper quenches, but deviates at shallower quenches, whose origin we discuss. CHC correctly describes demixing length and time scales, except for quenches into the vicinity of the spinodal boundary. Our data demonstrate the significant effect of relatively minor polymer microstructure variations on polymer blend behavior across both sides of the phase boundary.

Compatibilization of natural rubber–polypropylene thermoplastic elastomer blend

The effects of the addition of epoxidized natural rubber/maleic anhydride-grafted polypropylene blend as a compatibilizing agent (CA) on the properties of natural rubber (NR)/polypropylene (PP) thermoplastic elastomer blend were studied. The blends were prepared in the molten state at 180°C using a Brabender Plasticorder at a rotor speed of 60 r min−1. Evidence of compatibilization was obtained from the Brabender plastograms and from the mechanical properties results as well as the morphological analysis. It was found that the addition of the CA at different contents resulted in an increase of the tensile strength and Young’s modulus and a decrease of the elongation at break. It was also found that the melting temperature remained unchanged, the % crystallinity decreased, but the thermal stability was not affected. The morphology revealed a more homogeneous distribution of the dispersed PP phase for the CA-containing systems compared to the control NR/PP blend. These effects were attributed to the interactions that developed with the blend constituents through the functional groups of the CA.

English

The effect of pasteurisation parameters and formulation components on the nutritional composition (carbohydrate, protein, fat, ash and moisture contents) of tigernut-soy milk blend was investigated. Twenty-six different formulations (F1 – F26) were prepared from tigernut and soy milk. The process treatments employed were; pasteurisation temperature, pasteurisation duration and mixing duration which varied from 60 – 80°C, 5-20 s and 5-15 min respectively. The results showed that F24 with blend constituents of 37, 5 and 50% of tigernut milk, soy milk, water and process treatments of 60°C, 20 s and 5 min of pt, pd and md respectively had the highest percentage of carbohydrate (12.53%) and fat (3.181%). The highest protein value (5.69%) was found in F11 with blend constituents of 27, 5 and 60% of tigernut milk, soy milk, water and process treatments of 80°C, 20 s and 5 min of pt, pd and md respectively. F23 with blend constituents of 11, 11 and 70% of tigernut milk, soy milk, water and process treatments of 80°C, 20 s and 5 min of pt, pd and md respectively had the highest ash (4.38%) content. The most abundant in moisture content (93.065%) was F18 with blend constituents of 5, 17 and 70% of tigernut milk, soy milk, water and process treatments of 60°C, 5 s and 5 min of pt, pd and md respectively. Pasteurised tigernut-soy milk is rich in nutritional quality. Key words: Pasteurisation, mixing, temperature, milk, ash, nuts, moisture content.

Influence of component fineness on hydration and strength development in ternary slag-limestone cements

The quest for sustainable alternatives to Portland cement has led to the exploration of a range of materials or their combinations, often with the aim of exploiting synergies in reactions or particle packing to maximize performance. Simultaneous optimization of both presents a viable option to increase the efficiency of cementitious materials. The objective of this study was to evaluate the effect of varying the fineness of the constituents in ternary blends of CEM I – granulated ground blast furnace slag (GGBS) - limestone on hydration kinetics and strength development.
 Eight (8) ternary cement mixes were tested at 0.5 water/binder (w/b) ratio. Hydration was followed by isothermal conduction calorimetry and setting time. In addition, X-ray powder diffraction, thermogravimetric analysis and compressive strength development up to 180 days of curing were assessed. The efficiency associated with changing the fineness of each component was evaluated in terms of the net heat of reaction and compressive strength. The results show that fine CEM I is critical for hydration at early age, and this is reflected in the compressive strength accordingly. The benefits associated with finer GGBS and similarly limestone depend on the fineness of the other constituents in the blend. Optimization of these should consider the inter-dependencies in terms of kinetics and microstructure development.