Particle Size Reduction Research Articles

Synthesis of an Eco-Friendly Xylooligosaccharides and Its Mechanistic Evaluation in Water-Based Drilling Fluids

This study investigates the preparation and application mechanism of Xylooligosaccharides (XOS), an environmentally friendly oligosaccharide additive derived from black fungus in water-based drilling fluids (WBFs). The distinctive molecular characteristics of XOS are revealed through Fourier-transform infrared spectroscopy. Thermogravimetric analysis confirms its stability at temperatures below 150 °C. In terms of performance enhancement, incorporating XOS improves rheological properties and filtration efficiency. Elevated XOS concentrations increase viscosity, diminish fluid loss, suppress clay hydration, and enhance cohesive strength, especially at higher temperatures. Additionally, incorporating XOS prompts the formation of a lubricating layer on particle surfaces, facilitating improved interaction between particles and the surrounding fluid. This layer substantially reduces friction coefficients, thereby significantly boosting the lubrication efficiency of the drilling fluid. At the microstructural level, the incorporation of XOS leads to noticeable microstructural refinement in the matrix mud cake, resulting in a smoother particle distribution due to interactions between XOS and particles. Mechanistically, introducing XOS results in a significant shift in the distribution of clay particle sizes. This phenomenon can be attributed to XOS’s ability to create a stable hydration film within the WBFs. As a result, this film mitigates particle aggregation, leading to a reduction in particle size. XOS emerges as a versatile and sustainable oligosaccharide inhibitor, effectively optimizing the performance of WBFs. Its diverse contributions to lubrication, inhibition, and microstructure refinement position XOS as a promising solution for efficiently extracting oil and gas resource.

Mechanochemically induced hydrometallurgical method for recycling d-elements from Li-ion battery cathodes

The exponential growth of the Li-ion battery (LIB) market necessitates the development of environmentally friendly and economically viable recycling technologies. One of the approaches for recycling and selective recovery of critical battery components is the hydrometallurgical method. Despite its effectiveness, this technology has notable drawbacks, including environmental pollution caused by corrosive waste, high energy consumption, and complexity. Herein we present a highly efficient mechanochemically (MC) induced acid leaching process that enables the extraction of transition metals as water-soluble salts from cathode materials of different and mainly used chemistries such as LiCoO2, LiMn2O4, and Li(CoNiMn)O2. The described method utilizes HNO3, H2SO4, and HCl mineral acids to leach transition metal composites obtained by MC reduction and delithiation processes. The presented technology achieves a significant material dissolution efficiency of more than 95 % at low acid concentrations at room temperature. Furthermore, it was concluded that the mechanochemical pretreatment step plays a crucial role in reducing particle sizes as well as for the chemical reduction of d-elements in the cathode materials to lower electrochemical charging states which greatly enhances the effectiveness of the leaching process. This advancement brings us closer to achieving ecological and economic feasibility in recycling Li-ion batteries.

Microstructure evolution law and dissolution time effect of bituminous coal under acetic acid acidification: Based on Micro-CT image analysis

Undeveloped pores and fractures in coal seams constrain coalbed methane mining and dust disaster prevention significantly. The existing hydraulic fracturing technology has achieved some effects in coal seam modification. Still, there are hidden dangers in inducing microseismicity and other aspects. Applying acidification technology for pore and fracture modification improves the efficiency of coalbed methane mining and dust suppression. In this paper, 75% concentration of acetic acid was utilized to treat columnar coal samples, and the experimental method of X-ray computed tomography was applied to study the role of dissolution time on the microcomponents and structure of samples. The experimental results showed that the porosity increased with the dissolution time; the effect of acetic acid on the pore expansion and mineral dissolution showed three periods, i.e., the beginning of the reaction period (0 ∼ 12 h), the full reaction period (12 ∼ 48 h), and the reaction slowing down period (>48 h). The mineral volume fraction showed an overall decreasing trend; before 36 h, the dissolution of acetic acid on the mineral structure within the coal was faster, making it loose, which in turn accelerated the dissolution of coal, and after 36 h, the dissolution effect of acetic acid weakened, and the mineral was gradually stabilized. Acetic acid first reacts with minerals in large quantities. With the increase of products, the solution's ionic complexity increases, so acetic acid accelerates the ionization of more H+ ions, and the solution's acidity increases. After a while of dissolution, the content of acetic acid decreases, the ionized H+ ions are not enough to continue to react with the minerals, and the rate of the mineral's crystal particle size reduction slows down gradually. In conclusion, acetic acid has the potential for pore and fracture modification of coal reservoirs. It can affect the mineral through dissolution, at the same time, improve the porosity. The research results provide an essential reference for using acidification technology to modify the pores and fractures in coal seams.

Predicting crystallite size of Mg-Ti-SiC nanocomposites using an adaptive neuro-fuzzy inference system model modified by termite life cycle optimizer

In this study, Mg-Ti-SiC composite powders with varied micron and nano silicon carbide (SiC) particle sizes were fabricated utilizing the ball milling technology at various milling times. The effect of reinforcement particles sizes and milling time on the morphology and microstructure of the magnesium composite powders was characterized. Then, we developed a machine-learning model based on Adaptive Neuro-fuzzy Inference System (ANFIS) modified with termite life cycle optimizer to predict the crystallite size of the produced composites. The average particles size in all composites including micron SiC (µSiC) and nano SiC (nSiC) always decreased with increasing milling time and SiC content, and the most optimal reduction in particle size was achieved after 16 h of milling for both configurations, which were 5.12 µm and 1.96 µm, respectively. Changing reinforcement particle size from micron to nano caused the peak intensities of Mg and Ti more decreased and phases Ti5Si3 and TiC were observed after milling for 16 h in ND composite powder. With increasing milling time in Mg-25 wt% Ti-5 wt% µSiC, the crystallite size decreased from 31 nm to 13.62 nm after 1 h and 32 h milled, respectively. The most optimum reduction in crystallite size occurred in the composite powders including nSiC, in which crystallite size decreased to 13.35 nm. The developed Machine learning model was able to predict the evolution of the crystallite size of the produce d composites with very good accuracy.

Phosphorous, boron and sulphur-doped silver tungstate-based nanomaterials toward electrochemical methanol oxidation and water splitting energy applications

We employed a one-step precipitation approach to produce B, P, and S-doped Ag2WO4 (AgW) with the aid of a cetyltrimethylammonium bromide template in order to develop novel catalytic materials with components and architectures that tolerate harsh conditions. The P@AgW with the spherical (13.7 nm) shape was found to possess the greatest electrocatalytic activity for the oxidation of methanol in an acidic environment. It provides remarkable performance with an overpotential of 0.58 V (at a current density of 10 mA cm−2 comprised of mass activity of 1172 mA g−1) and considerable long-term reliability. This is attributed to the intense increase in the β-Ag2WO4/α-Ag2WO4 ratio (4:1), the formation of Ag–O–P, the highest electrochemical surface area, and the ease of charge transfer. The B@AgW electrode of polymorphic structure, on the other hand, performed the best for water electrolysis in the basic medium (1.0 M KOH). It produces an OER at overpotentials of 50 mA cm−2 at 0.42 V and 399 mV at 10 mA cm−2. At 10 mA cm−2, the HER overpotential was 0.33 V. Additionally, the B@AgW electrolyzer shows a cell voltage of 1.44 V for overall water splitting, which is lower than that of P@AgW (1.56 V), and it demonstrates great durability for 20 h. The notably higher activity of B@AgW compared to other electrolyzers is due to improved electrical conductivity, transport of mass, more active sites, and reduced particle size (7.2 nm). This work offers a simple way for the large-scale manufacture of electrocatalysts with considerable activity and reliability over time.

Solubility Enhancement of Poorly Water-Soluble Drugs by Solid Dispersion Techniques

The fact that newly discovered API’s (about 90%) or new molecular entity (NME) have little or poor aqueous solubility, causes a significant challenges to the initialization of development and commercialization of dosage form at the manufacturing facility. Poor aqueous solubility of API’s has critical role in drug dissolution or availability of drug at the site of actionor bioavailability, when a dosage form is administered orally. Various techniques are available for the enhancement of solubility but all individual techniques have its own limitations for commercialization. The known Solubility enhancement techniques like Solid dispersions involved the dispersion of poorly soluble drug in a suitable inert carrier at a molecular level and form amorphous and highly soluble compounds. The conversion of compound in to amorphous form or reduction of particle size to its molecular level caused enhanced solubility of poorly soluble by the application of solid dispersion techniques.

Anomalous Temperature-Induced Particle Size Reduction in Manganese Oxide Nanoparticles.

The intricate role of temperature in the structure-property relationship of manganese oxide nanoparticles (Mn3O4 NPs) remains an open question. In this study, we successfully synthesized Mn3O4 NPs using the hydrothermal method with two differing temperatures, namely, 90 and 150 °C. Interestingly, a smaller average particle size is found when Mn3O4 NPs are synthesized at 150 °C compared to 90 °C, corresponding to 46.54 and 63.37 nm, respectively. This was confirmed by the time variation of temperature setting of 150 °C where the size evolution was insignificant, indicating a competing effect of nucleation and growth particles. Under varying NaOH concentrations (2-6 M) at 150 °C, a reduction in the particle size is found at the highest NaOH concentration (6 M). The particle grows slightly, indicating that the growth state is dominant compared to the nucleation state at low concentrations of NaOH. This finding implies that the high nucleation rate originates from the excessive monomer supply in the high-temperature reaction. In terms of crystallinity order, the structural arrangement of Mn3O4 NPs (150 °C) is largely decreased; this is likely due to a facile redox shift to the higher oxidation state of manganese. In addition, the higher ratio of adsorbed oxygen and lattice oxygen in Mn3O4 NPs at 150 °C is indirectly due to the higher oxygen vacancy occupancies, which supported the crystallinity decrease. Our findings provide a new perspective on manganese oxide formation in hydrothermal systems.

Temperature-driven magnetic and structural transitions in multiferroic Lu(1-x)ScxFeO3

Novel metastable hexagonal Lu(1-x)SxFeO3 compounds were prepared by an ethylene glycol-based small molecule sol-gel synthesis route. Samples were investigated by means of XRD, Raman spectroscopy, XPS, SEM and magnetometry techniques. Based on the obtained data several different phase composition regions were discovered at room temperature depending on the Sc content. Three dominant phases were observed and denoted as the orthorhombic Pnma, hexagonal P63cm, and cubic Ia-3 with the hexagonal phase being stable without any additional phases when 0.40 ≤ x < 0.65. Temperature dependent structural analysis allowed for the construction of the phase diagram which revealed that upon increasing Sc content the reversible polar to non-polar phase transition temperature can be decreased from above 1200 °C (when x = 0.15) to around 800 °C (x = 0.75). SEM analysis indicated a rapid reduction in particle size from ∼2.726 µm when x = 0 down to ∼0.962 µm when x = 0.75, however in the case when x = 1, an increase in particle size was observed. XPS analysis confirmed the elemental composition and its changes as well as the stability of the 3 + oxidation state of the iron ions. Magnetization measurements confirmed a non-zero room temperature magnetization as well as the spin reorientation transitions whose critical temperatures TN increases from 156 K (x = 0.25) to 170 K (x = 0.75).

Supercritical fluid-assisted fabrication of CuxOSAS-based electrochemical sensor for cysteine detection with enhanced sensitivity and reduced oxidation potential

This work demonstrates a rapid and effective strategy to make a cysteine detection system with higher sensitivity and lower detection limit using an eco-friendly supercritical antisolvent (SAS) technology. Copper salt particles were prepared via SAS and transformed into copper(I/II) oxide (CuxOSAS) upon calcination at 400℃. The resulting calcinated product exhibited a significantly reduced particle size and the presence of mixed valence states. The fabricated CuxOSAS cysteine detection system demonstrated excellent performance, with a cyclic voltammetry (CV) curve displaying a low oxidative overpotential (∼0.1 V vs. Ag/AgCl). The linear detection range was 0.001 μM to 0.25 μM and 0.25 μM to 1000 μM, respectively, with corresponding sensitivity of 2447.1 μA·cm−2·μM−1 and 0.3714 μA·cm−2·μM−1, respectively. In conclusion, the SAS-prepared CuxOSAS hold great prospective for electro-sensing and biomolecular catalysis applications.

Acid Hydrolyzed Pearl Millet Starch Nanoparticles: Synthesis and Characterization

AbstractThe amylose content in native starch is reduced through hydrolysis, impacting its physicochemical properties. Starch nanoparticles exhibit enhanced water and oil absorption capacities, attributed to increased hydrolysis and subsequently higher solubility. Moreover, the swelling power of starch nanoparticles is notably higher, indicating improved functionality. Pasting properties are altered, with reduced peak viscosity, breakdown viscosity, and setback viscosity in modified starches. Dynamic light scattering reveals a significant reduction in particle size for starch nanoparticles compared to native starch. Morphological analysis using field emission‐scanning electron microscopy (FE‐SEM) highlights distinct granule shapes and surfaces between the two starch types. The X‐ray diffraction patterns confirm an A‐type crystalline structure in both native and modified starches. Fourier transform infrared (FTIR) spectroscopy verifies no significant difference in functional groups due to extraction or hydrolysis methods. This comprehensive investigation provides valuable insights into the chemical modification of pearl millet starch, shedding light on its potential applications in various industries, including food and pharmaceuticals.

Direct Synthesis of Metal-Organic Framework Sols: Advances and Perspectives.

The intrinsic lack of processability in the conventional nano/microcrystalline powder form of metal-organic frameworks (MOFs) greatly limits their application in various fields. Synthesis of MOFs with certain flowability make them promising for multitudinous applications. The direct synthesis strategy represents one of the simplest and efficient method for synthesizing solution processable MOF sols/suspensions, compared with other approaches, for instance, the post-synthesis surface modification, the direct dispersion of MOFs in hindered ionic liquids, as well as the calcination method toward a few MOFs with melting behavior. This article reviews the recent direct synthesis strategies of solution processable MOF sols and their typical applications in different fields. The direct synthesis strategies of MOF sols can be classified into two categories: particle size reduction strategy, and selective coordination strategy. The synthesis mechanism of different strategies and the factors affecting the formation of sols are summarized. The application of solution processable MOF sols in different fields are introduced, showing great application potentials. Furthermore, the challenges faced by the direct synthesis of MOF sols and the main methods to deal with the challenges are emphasized, and the future development trend is prospected.

Net energy content of hybrid rye fed to growing pigs and effects of particle size on energy values

An experiment was conducted to determine the digestible energy (DE), metabolizable energy (ME), and net energy (NE) contents of hybrid rye fed to growing pigs using indirect calorimetry and to investigate the effects of particle size on energy values. Thirty growing barrows (18.06 ± 0.83 kg initial body weight) were individually housed in metabolism crates and randomly allotted to one of five dietary treatments to give six replicates per treatment. Two hybrid rye varieties (Bono and Gatano) were ground in a hammermill mounted with a 4.0-mm or 3.2-mm screen to obtain coarse and fine particle size, respectively. Dietary treatments included a corn-soybean meal basal diet and four additional diets containing 300 g/kg of the test ingredients in a 2 × 2 factorial based on hybrid rye variety (Bono or Gatano) and particle size (Coarse or Fine). Pigs were fed experimental diets for 15 days, including 10 days for adaptation and 5 days for total fecal and urine collection to determine the DE and ME of the experimental diets. Pigs were then moved into indirect calorimetry chambers to determine 24-h heat production and 12-h fasting heat production. All data were analyzed using the MIXED procedure of SAS with the individual pig as the experimental unit. The geometric mean diameter (Dgw) for coarsely versus finely ground Bono and Gatano were 1111 versus 594 µm and 1210 versus 717 µm, respectively. The coefficient of apparent total tract digestibility (CATTD) of dry matter (DM) and gross energy (GE) were greater (P < 0.05) in diets containing finely than coarsely ground hybrid rye. The DE and ME of finely ground hybrid rye were greater (P < 0.05) than those of coarsely ground hybrid rye, and the NE of finely ground hybrid rye tended to be greater (P = 0.084) than that of coarsely ground hybrid rye. No differences were observed for the DE, ME, and NE contents between Bono and Gatano. The determined NE for coarsely and finely ground Bono were 11.06 and 11.77 MJ/kg DM, and the respective NE values for coarsely and finely ground Gatano were 11.09 and 11.57 MJ/kg DM. In conclusion, the energy values of different hybrid rye varieties might be comparable. Particle size reduction could significantly improve the DE and ME values of hybrid rye fed to growing pigs, while the NE value was only numerically improved.

Effect of magnesium stearate solid lipid nanoparticles as a lubricant on the properties of tablets by direct compression

This study discusses the lubricant properties of magnesium stearate solid lipid nanoparticles (MgSt-SLN) and their effect on the tabletability, mechanical properties, disintegration, and acetaminophen-model dissolution time of microcrystalline cellulose (MCC) tablets prepared by direct compression. The behavior of MgSt-SLN was compared to reference material (RM) to identify advantages and drawbacks. The nanoprecipitation/ion exchange method was employed to prepare the MgSt-SLN. Particle size, zeta potential, specific surface area, morphology, and true density were measured to characterize the nanosystem. The MgSt-SLN particle sizes obtained were 240 ± 5 nm with a specific surface area of 12.2 m2/g. The MCC tablets with MgSt-SLN presented a reduction greater than 20 % in their ejection force, good tabletability, higher tensile strength, lower disintegration delay, and marked differences in acetaminophen dissolution when compared to the RM. The reduced particle size of the magnesium stearate seems to offer a promising technological advantage as an efficient lubricant process that does not affect the properties of tablets.

An innovative dual-strengthening pretreatment to improve Li and Co leaching in spent lithium-ion batteries: Pyrolysis combined with mechanical grinding

The presence of PVDF prevents the contact of leaching solution and LiCoO2, which is the decisive factor leading to the low leaching efficiency of electrode materials. Therefore, a dual-strengthening pretreatment method is proposed to remove PVDF more efficiently and enhance the leaching of the LiCoO2. To determine the enhanced effect of the PVDF removal and the leaching of LiCoO2 treated by dual-strengthening pretreatment, the leaching behavior of the untreated, ground, pyrolyzed and dual-strengthening pretreated LiCoO2 were compared. XPS and SEM-EDS were used to evidence the removal of the PVDF, while the XRD was used to analyze the composition of the leaching slag to evidence the leaching behavior. The XPS results show that dual-strengthening pretreatment on PVDF removal is better than that of the single treatment. SEM confirms that the electrode material can achieve the double effect of pyrolysis residue removal and particle size reduction after dual-strengthening. The leaching enhancement of dual-strengthening is more significant than the single pretreatment, and the improvement of single pyrolysis is greater than that of grinding by detecting the leaching rate of Li and Co using ICP-MS. The leaching rate of Li and Co in the dual-strengthening LiCoO2 is 96.25 % and 95.21 %, it is 95.16 % and 94.50 % in the pyrolyzed LiCoO2, while it is 73.96 % and 66.78 % in the ground LiCoO2. The mechanism of the dual-strengthening treatment lies in the full removal of PVDF to expand the dispersion of LiCoO2 particles. The present study provides an innovative strengthening approach to LiCoO2 leaching.

Formulation of Seaweed (Eucheuma cottonii Doty) Lotion

Seaweed (Eucheuma cottonii Doty) has potential as an antioxidant because it contains kappa-carrageenan which can counteract free radicals. Formulation of seaweed (Eucheuma cottonii Doty) into lotion preparations can minimize the negative effects of sun exposure, because it can reflect solar radiation or work as a physical sunscreen. To give the maximum effect, particle size reduction is carried out, so that the smaller the particle size of the seaweed powder, the surface area increases. This study aims to determine the formulation and evaluate the preparation of lotion from seaweed powder. This research was conducted using an experimental method. The lotion was made with three variations of seaweed powder concentration (Eucheuma cottonii Doty), namely 2.5%, 3% and 5%. Tests were carried out before and after accelerated conditions at 5oC and 35oC for 12 hours each for 12 cycles with test parameters including organoleptic, homogeneity, pH, spreadability, viscosity and flow type. The results obtained in the organoleptic test showed no change in the three formulas both before and after the accelerated condition. The pH test showed that Formula 2 and Formula 3 still showed that the preparation remained in the skin pH range for sunscreen. In the homogeneity test, all preparations were homogeneous, as well as the spreadability test met the test requirements criteria. Based on the tests carried out, it can be concluded that formulas 2 and 3 have optimum stability.

Microstructural Characterization of Al0.5CrFeNiTi High Entropy Alloy Produced by Powder Metallurgy Route.

Alloys with superior properties represent the main topic of recent studies due to their effectiveness in reducing the cost of equipment maintenance and enhancing usage time, in addition to other benefits in domains such as geothermal, marine, and airspace. Al0.5CrFeNiTi was produced by solid state processing in a planetary ball mill, with the objective of obtaining a high alloying degree and a homogenous composition that could be further processed by pressing and sintering. The metallic powder was technologically characterized, indicating a particle size reduction following mechanical alloying processing when compared to the elemental raw powder materials. The microstructural analysis presented the evolution of the alloying degree during milling but also a compact structure with no major defects in the pressed and sintered bulk samples. The X-ray diffraction results confirmed the presence of face-centered cubic (FCC) and body-centered cubic (BCC) phases, predicted by the theoretical calculations, along with a hexagonal close-packed (HCP) phase, where the Al, Cr, Fe, Ni, and Ti phase was identified in both the alloyed powder material and sintered sample.

Isothermal and Kinetic Studies for the Removal of Malachite Green and Congo Red Dyes Using Wastes from Mining and Processing Perlite in Different Particle Sizes as Sustainable Adsorbents

Perlite waste materials with different particle sizes were evaluated as potential candidates for removing the malachite green (MG) and Congo red (CR) dyes from contaminated water. Two types of waste, referred to as coarse (CP) and fine (FP), with particle sizes of 0.075 mm, 0.045 mm, and 0.037 mm, were used. The samples were characterized using X-ray diffraction, X-ray fluorescence, Fourier transform infrared spectroscopy, and N2 adsorption/desorption. The adsorption efficiency of MG and CR was investigated by varying the parameters of pH, contact time, and initial concentration. The reduction in particle size significantly influenced the removal of the CR dye, leading to an increase in the adsorption rate of 23.9% and 45.5% for CP and FP, respectively. Conversely, the adsorption of the MG dye on the residues was not affected by different particle sizes. CP and FP exhibited a removal rate exceeding 70% for both dyes. The adsorption of MG and CR on the wastes was well-described by the Sips isotherm model. The results of adsorption kinetics were best fit by the Elovich model. Perlite waste materials have demonstrated significant potential for the adsorptive remove of cationic and anionic dyes from aqueous solutions.

Effects of particle size reduction of meadow hay on feed intake, performance, and apparent total tract nutrient digestibility in dairy cows

ABSTRACT Forage-based diets are encouraged in organic dairy cattle production as this can increase the net human food supply, but their voluminous nature can limit dry matter intake (DMI) and performance. This study investigates the effects of a substantial particle size reduction of hay on dairy cows’ feed intake, performance, and body characteristics, as well as on apparent total tract digestibility (ATTD). Eighteen lactating Holstein cows were allocated to two balanced feeding groups. The control group received long stem hay with a conventional particle size (CON), the experimental group received chopped hay (RED). Both groups were supplemented with concentrates (3.6 kg/d, DM basis). After 14 adaptation days, data were collected for 20 consecutive days. A covariate period of 21 days preceded the experimental feeding period. Particles retained on the 19-, 8- and 4-mm screens and on the pan of the Penn State Particle Separator accounted for 21%, 20%, 20% and 39% of the RED hay. CON hay consisted of 72% large particles, followed by 8%, 7% and 13% retained on the other screens. Average DMI levels of cows in the CON group reached 20.8 kg/d, with a nonsignificant increase (+1.05 kg/d) in the RED group (p = 0.28). Intakes of both NFC (+0.65 kg/d, p = 0.01) and CP (+0.28 kg/d, p = 0.05) were significantly greater in the RED group, resulting in a slightly increased milk yield (+0.8 kg energy corrected milk/d) (p = 0.45), likely because the ATTD decreased significantly when feeding RED hay. No impact was observed on energy balance (103.7 vs 103.9%, p = 0.95), feed conversion efficiency (kg ECM/kg DMI), or N use efficiency. Overall, the results indicate increases in intake of NFC and CP in the RED group when feeding a hay-based (>83%, DM basis) diet, but also a decrease in nutrient digestibility, likely due to increased passage rate, potentially because of the high fraction of hay particles < 4 mm. In conclusion, hay-based rations with a lower proportion of fine particles should be tested to exploit the potential of particle size reduction in terms of improving hay use efficiency.

Recycling of Wood–Plastic Composites—A Reprocessing Study

Wood–plastic composites, consisting of wood particles and a thermoplastic matrix, are common composites often used in buildings as decking boards or for similar non-load-carrying applications. As these are usually semi-finished products, a certain amount of material is available after cutting these to size, in the factory and also at installation sites. Especially for in-house waste streams in factories, the question remains whether these materials can be reprocessed without any negative influence on the materials’ properties. Therefore, the aim of this work is to investigate the influence of reprocessing on the property profile of polypropylene based wood–plastic composites. Two base formulations with 40 wt% of wood particles and two different polypropylene grades were investigated for their mechanical properties, wood particle size, color, weathering stability and water uptake. We found that most of the wood–plastic composites’ properties were not negatively influenced by the multiple processing steps; the most pronounced effect beside particle size reduction is color degradation, as the composites darken with increasing number of processing steps. In our opinion this shows, that wood–plastic composites can be recycled, especially if these are only reprocessed in smaller shares together with virgin materials.

Effects of pre-drying treatment and particle sizes on physicochemical and structural properties of pumpkin flour

The objective of this study is to investigate the effect of pre-drying treatment and particle size on pumpkin flour's compositional, functional, pasting, thermal, and structural properties. Pre-drying treatment and reducing the size of particles have led to an increase in the levels of crude fiber, phytochemicals, and functional properties. However, the amounts of moisture and lightness of color decreased with pretreatment, but improved with particle size reduction. Among the samples, those that were finely milled after pre-treatment showed the highest viscosities, while the untreated samples that were coarsely milled had lower viscosities. The pre-drying treatments yielded notable reductions in both gelatinization temperature and enthalpy of the flour matrix, in comparison to untreated flours. FTIR analysis has indicated that no new functional groups were produced. XRD analysis suggests that while pre-drying treatment leads to decreases in crystallinity index, fine milling leads to increments. The morphological pattern suggested that pretreatment effectively altered the original surface structure of the flour, but particle size reduction did not.