Relationship Between Elastic, Chemical, and Thermal Properties of SiO2 Flint Aggregate.

This study investigates the mechanical, thermal, and chemical properties of basalt/woven glass fiber reinforced polymer (BGRP) hybrid polyester composites. The Fourier transform infrared spectroscopy (FTIR) was used to explore the chemical aspect, whereas the dynamic mechanical analysis (DMA) and thermomechanical analysis (TMA) were performed to determine the mechanical and thermal properties. The dynamic mechanical properties were evaluated in terms of the storage modulus, loss modulus, and damping factor. The FTIR results showed that incorporating single and hybrid fibers in the matrix did not change the chemical properties. The DMA findings revealed that the B7.5/G22.5 composite with 7.5 wt% of basalt fiber (B) and 22.5 wt% of glass fiber (G) exhibited the highest elastic and viscous properties, as it exhibited the higher storage modulus (8.04 × 109 MPa) and loss modulus (1.32 × 109 MPa) compared to the other samples. All the reinforced composites had better damping behavior than the neat matrix, but no further enhancement was obtained upon hybridization. The analysis also revealed that the B22.5/G7.5 composite with 22.5 wt% of basalt fiber and 7.5 wt% of glass fiber had the highest Tg at 70.80 °C, and increased by 15 °C compared to the neat matrix. TMA data suggested that the reinforced composites had relatively low dimensional stabilities than the neat matrix, particularly between 50 to 80 °C. Overall, the hybridization of basalt and glass fibers in unsaturated polyester formed composites with higher mechanical and thermal properties than single reinforced composites.

Natural fibers are good substitute for polymer fibers due to its better characteristics like biodegradable, low cost and no harmful release. The purpose of this research is to identify a natural fiber with low cost and good characteristics. Hence, in this research, an attempt has been made to analyze the physical, chemical and thermal properties of banana flower pistil fiber (BPF). The fibers were involved into chemical treatment such as alkali (5%, 7.5% and 10%). The effect of chemical treatment on the properties of fiber was analyzed. Structural properties were analyzed by X- Ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). The thermal properties were tested by Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC). Further, the water absorption ability of the treated and untreated fiber was investigated. Results showed that the chemically treated fiber (5% alkali) displayed good physical, chemical and thermal properties compared to untreated fiber. Hence, the chemically treated BPF could be useful in the fabrication of bio-composites for industrial applications.

Linseed straw is the stalk or stem of the linseed plant that remains after the seeds have been harvested. This agricultural waste is generated every year and is mostly left or burned in fields, causing environmental problems. This study focuses on the isolation and characterization of crystalline nanocellulose (CNC) from linseed straw fibers as a potential alternative source. The CNCs were isolated using sequential chlorine-free chemical and mechanical treatments, involving three main steps: pre-treatment, acid hydrolysis, and post-treatment. The isolated CNC was thoroughly characterized for its morphology, particle size, aspect ratio, crystallinity, crystallite size, cellulose polymorph, thermal properties, and chemical composition, compared to raw fiber (RF) and micro cellulose (MC). Characterization techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FT–IR) were employed. The rod-like CNCs obtained exhibited a yield of 79.87 ± 1.35%, with a mean diameter of 7.06 ± 1.95 nm and a length of 66.14 ± 28.58 nm. The aspect ratio was measured at 10.02 ± 4.87 nm, with a crystallinity index of 73.29% and a crystallite size of 5.61 nm. Additionally, the CNCs displayed an average molecular weight of 2.36 × 104 g/mol, an average degree of polymerization of 146, and a peak decomposition temperature of 515°C. These results suggest that linseed straw fibers are a promising source for the production of CNC, which can effectively serve as a filler in polymer composites.

This article presents a comprehensive study on the physical, mechanical, thermal, and chemical properties of polypropylene (PP) composites reinforced with hemp fibers (HF) and compatibilized with maleic anhydride (MAPP). The composites were processed using a twin-screw extruder, followed by hot compression at 190 °C. Subsequently, the composites were analyzed using Izod impact and Shore D hardness tests to evaluate their mechanical properties. Thermal properties were investigated through differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), while X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) were employed to study their chemical properties. Additionally, a statistical analysis was conducted to compare the average results of the impact and hardness tests. XRD analysis revealed that the addition of HF and MAPP led to the disappearance of peaks corresponding to the beta phase in pure PP. Hemp fibers exhibited an impressive crystallinity of 82.10%, surpassing other natural fibers, and had a significant molecular orientation angle (MFA) of 6.06°, making them highly desirable for engineering applications. The crystallite size was observed to be relatively large, at 32.49 nm. FTIR analysis demonstrated strong interactions between the fiber, compatibilizing agent, and polymer matrix. TGA tests showed that the addition of 5 and 10 wt.% MAPP resulted in complete degradation of the composites, similar to pure PP. DSC analyses indicated a reduction in crystallinity (Xc) due to the incorporation of HF and MAPP. Shore D hardness tests revealed an increase in hardness with the addition of 5 wt.% MAPP, while a steep decline in this property was observed with 10 wt.% MAPP. In terms of impact resistance, fractions of 3 and 5 wt.% MAPP in the composites exhibited improved performance compared to the pure polymer. Analysis of variance (ANOVA) was employed to ensure the statistical reliability of the mechanical test results. This comprehensive study sheds light on the diverse properties of PP composites reinforced with hemp fibers and compatibilized with MAPP, emphasizing their potential as sustainable materials for engineering applications. The results contribute to the understanding of the structural and functional aspects of these composites, guiding future research and developments in the field.

The effects of heat treatment at various temperatures on mechanically separated bamboo fibers and parenchyma cells were examined in terms of color, microstructure, chemical composition, crystallinity, and thermal properties. The heat-treated parenchyma cells and fibers were characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), chemical composition analysis, and thermogravimetric analysis (TGA). The results revealed that the colors of bamboo fibers and parenchyma cells were darkened as treatment temperature increased. The microstructure of the treated fibers and parenchyma cells slightly changed, yet the shape of starch granules in parenchyma cells markedly altered at a temperature of above 160 °C. The chemical compositions varied depending on the heat treatment temperature. When treated at 220 °C, the cellulose content was almost unchanged in fibers but increased by 15% in parenchyma cells; the hemicellulose content decreased and the lignin content increased regardless of fibers and parenchyma cells. The cellulose crystal structure was nearly unaffected by heat treatment, but the cellulose crystallinity of fibers changed more pronouncedly than that of parenchyma cells. The thermal stability of parenchyma cells after heat treatment was affected more substantially compared to fibers.

Impact of annealing on the characteristics of 3D-printed graphene-reinforced PLA composite

Simple SummaryAmong animal facilities, compost-bedded pack (CBP) barns have attracted a lot of attention from milk producers and the scientific community. Systematic investigation of the main thermal, chemical, and physical properties of bedding materials in CBP barns is of environmental and economic relevance, helping dairy producers operate these beds properly. Here we assessed 42 CBPs in the state of Kentucky (USA), aiming to study the thermal, chemical, and physical properties of bedding materials. We found that thermal conductivity increased with increasing particle size. Regarding chemical features, the assessed CBPs were similar when considering the bedding materials. The particle weight fraction found in CBPs might result in excessive water retention and low aeration. Based on these main results, we concluded that many dairy producers could use the bedding compost to fertilize their crop fields and avoid over-applying nutrients, and reduce water pollution.The thermal, chemical, and physical properties of compost bedding materials play an important role in every phase of compost production. Based on this, we aimed to assess the thermal, chemical and physical properties of bedding materials for compost-bedded pack (CBP) barns. The database for this study was registered from 42 CBP barns, distributed throughout the state of Kentucky (USA). The thermal conductivity showed a linear relationship with moisture content and bulk density, while thermal resistivity decreased with increasing particle size. The bedding moisture average was 46.8% (±11.5). The average finer index (p < 0.05) was the highest weight percentage (30.1%) in the samples studied. Water-holding capacity (WHC) increased with increasingly fine particle size. The higher bulk density value was 3.6 times that of the lowest bulk density value. The chemical characterization of the bedding material provided the following results: 42.7% (±3.8%) C, 1.6% (±0.4%) N, and 28.2 (±8.0) C:N ratio. However, thermal properties are strongly dependent on particle size. Producers can use the bedding material as fertilizer in their crops, due to the chemical characteristics of the materials. Beds with good physical and chemical properties improve their moisture content.

The aim of this work was to investigate the thermal and mechanical properties of novel, electron beam-modified ester elastomers containing multifunctional alcohols. Polymers tested in this work consist of two blocks: sebacic acid–butylene glycol block and sebacic acid–sugar alcohol block. Different sugar alcohols were utilized in the polymer synthesis: glycerol, sorbitol, xylitol, erythritol, and mannitol. The polymers have undergone an irradiation procedure. The materials were irradiated with doses of 50 kGy, 100 kGy, and 150 kGy. The expected effect of using ionizing radiation was crosslinking process and improvement of the mechanical properties. Additionally, a beneficial side effect of the irradiation process is sterilization of the affected materials. It is also worth noting that the materials described in this paper do not require either sensitizers or cross-linking agent in order to perform radiation modification. Radiation-modified poly(polyol sebacate-co-butylene sebacate) elastomers have been characterized in respect to the mechanical properties (quasi-static tensile tests), cross-link density, thermal properties (Differential Scanning Calorimetry (DSC)), chemical properties: Fourier transform infrared spectroscopy (FTIR), and wettability (water contact angle). Poly(polyol sebacate-co-butylene sebacate) preopolymers were characterized with nuclear magnetic resonance spectroscopy (1H NMR and 13C NMR) and gel permeation chromatography (GPC). Thermal stability of cross-linked materials (directly after synthesis process) was tested with thermogravimetric analysis (TGA).

Background:The impact of different physical and/or chemical treatments in cereal grains on starch morphology and ruminal digestibility has been evaluated. Aims:The effect of chemical and/or physical treatments on starch and protein molecular appearance and the ex-vivo digestibility of barley grain was studied. Methods:Treatments were: steam-flaked barley grain (SFB), SFB treated with ammonium bicarbonate (A), urea (U), and malic acid (M) (SFBAUM), SFB treated with A, U, and lactic acid (L) (SFBAUL), steam-infrared heated-flaked barley grain (SIFB), SIFB treated with A, U, and M (SIFBAUM), and SIFB treated with A, U, and L (SIFBAUL). Chemicals including A, U, M, and L were used as 56, 8, 10, and 10 g/kg dry matter (DM), respectively. Chemical composition and molecular morphology were determined using scanning electron microscopy and Fourier-transform infrared spectroscopy (FTIR). In situ mobile bag technique and in vitro batch culture procedure were used to estimate ruminal and post-ruminal digestibility. Results:Crude protein (CP) and starch concentrations in SFBAUL were higher than the others (P<0.05). Starch granule morphology and protein structure were altered in the chemically treated samples. The potentially digestible fraction of DM was the highest in the SFBAUM (P<0.05). Ruminal disappearance of DM, CP, and starch was improved in SFBAUL and SIFBAUL compared with other groups (P<0.05). The highest post-ruminal digestibility of starch and CP was observed in SIFBAUL and SIFB (P<0.05). Conclusion:Present results indicate that chemical processing with L and applied steam-infrared heated-flaked in barley grain may improve in vitro digestibility of starch and CP and increase granule sizes.

Thermoplastic vulcanizates (TPVs) offer a sustainable alternative to conventional rubber in material design as they can be reprocessed similarly to thermoplastics. However, it is crucial to investigate the effects of reprocessing to evaluate the differences between virgin and recycled forms. In this study, EPDM/PP‐based TPV was exposed to multiple extrusion cycles, during which the material was exposed to high mechanical and thermal stresses. Therefore, a comprehensive analysis was carried out by examining the material's mechanical, thermal, and rheological properties. Chemical degradation after each processing stage was evaluated via Fourier Transform Infrared Spectroscopy (FTIR), and the results showed no noticeable change in chemical composition. Similarly, mechanical and elastic properties were extensively tested via compression set, tensile, tear, and hardness tests, and no negative effect on mechanical performance was observed. The rheological properties of the reused materials did not adversely affect their processability. Overall, results indicated that the main characteristics remained stable even after multiple extrusion cycles. Consequently, these findings show that EPDM/PP‐based TPVs can be reused multiple times without any negative impact on material properties.

Diss fibers, also called Ampelodesmos mauritanicus, are one of the least studied fibers in the literature. Indeed, the rare studies discussed have focused on mechanical and physicochemical properties. The present work deals with hygrothermal characterization and the effect of treatments on their behavior. So, untreated and treated Diss fibers with chemical treatments (alkaline, silane, and acetic acid) and heat treatment were characterized by absorption tests by water immersion and others by water vapor adsorption and desorption (Proumid-SPS). The results found have shown that these fibers presented a type II sorption isotherm with hysteresis where their saturation point could reach up to 40% of their dry mass. However, the treatments carried out seem to be able to reduce their hydrophilic nature especially after heat, silane, and acetic acid treatments. The adsorption kinetics, on the other hand, also seem to be positively influenced by these treatments, especially after the chemical treatments.

A suitable material for wind turbine blades has promoted great interest in carbon-based thermoplastic polyurethane (TPU) composites as they are flexible, lightweight, and mechanically robust. However, these carbon-based fillers deteriorate the thermal and mechanical properties in the long run due to the high agglomeration of the nanoparticles. In addition to that, these fillers also increase the production cost because of the chemical treatment conducted on the fillers. Therefore, a new approach is essential for maintaining the mechanical and thermal properties without using expensive chemical treatment in a low-cost platform. In this work, we present low agglomeration with even distribution of reinforcing fillers in the TPU matrix and robust mechanical and thermal properties by incorporating TiO2 in the carbon-based TPU matrix (TiO2/MWCNT/TPU), without inclusion of costly chemical treatments. TiO2 improves morphology due to the low valency of Ti2+, which may decrease the particle size and thus, reduces agglomeration. Moreover, the enhanced morphology assists in sustaining the rigidity of its molecular structure at high temperatures. The composite also reveals excellent mechanical properties of high tensile stress (4.46 MPa), more extended elongation at break (49%), and high Young's Modulus (9.17 MPa). The thermal analysis using DMA and TGA revealed that the sample TiO2/MWCNT/TPU is a good heat insulator and has a high glass transition temperature compared to the neat TPU indicating its ability to sustain rigidity at high temperatures overall, this composite can perform in elevated weather conditions.

Influences of sodium hydroxide and oxalic acid treatments on physical, mechanical, thermal properties, and morphology of ramie fibers

The increasing demand for natural fiber-reinforced composites has opened up the market for inexpensive, lightweight, bio-renewable, and environment-friendly plant fibers. The chemical treatments on fiber lead to the reduction of lignin and hemicellulose contents which helps in better adhesion with the matrix. The objective of this work is to do various chemical treatments on Cissus quadrangularis Stem Fiber (CQSF) and perform its characterization. The natural fibers are first extracted from the Cissus quadrangularis stem using the retting process. The fibers are then chemically treated with magnesium carbonate (MgCO3), sodium hydroxide (NaOH), sodium carbonate (Na2CO3), sodium bicarbonate (NaHCO3), and calcium hydroxide (Ca(OH)2). The characterization of single fibers is investigated by single-fiber tensile test, chemical composition, thermogravimetric analysis, and field emission scanning electron microscope. Characterization results show that the MgCO3-treated CQSF has improved mechanical and thermal properties. Thus, MgCO3-treated CQSF is suggested for biocomposite preparation due to its promising mechanical properties and thermal properties.

Microplastics (< 5 mm) are a diverse class of contaminants ranging in morphology, polymer type, and chemical cocktail. Microplastic toxicity can be driven by one or a combination of these characteristics. Most studies, however, evaluate the physical effect of the most commercially available polymers. By disregarding other polymers with high consumption and/or production rates, and the chemical constituents of plastics, we fail to have a holistic understanding of the mechanisms of toxicity. Polyurethane is understudied in terms of effects testing yet considered one of the most hazardous polymers due to its chemical composition. Polyurethane is a high production polymer and is found in common consumer products ranging from packaging to spray foam insulation. To better understand the physico-chemical effects of polyurethane and a common additive in polyurethane products, we exposed larval fathead minnows for 28 days to polyurethane without chemical additives (i.e., plastic treatment), chemical leachate from polyurethane containing chemical additives (i.e., tris(chloropropyl)phosphate [TCPP]; i.e., chemical treatment) and polyurethane with chemical additives (i.e., plastic with chemical treatment) in a fully factorial experiment. We observed significant decreases in growth at 12 days posthatch (dph) in the plastic, chemical, and plastic with chemical treatments, suggesting a physical and chemical driver of toxicity. At 28 dph, we did not observe significant differences in growth, suggesting individuals can recover. We also observed concentrations of ΣTCPPs in fathead minnow exposed to the plastic with chemical treatment and the chemical only treatment, demonstrating TCPP uptake in exposed individuals. Combined, our data suggests the importance of both the physical and chemical components of microplastics when assessing effects, and thus emphasizing the need to evaluate the effects of microplastics in a multidimensional way.