Cu2+-Zn2+/chitosan complexes, containing different proportions of cupric and zinc ions, utilized the amino and hydroxyl groups of chitosan as ligands, exhibiting a deacetylation degree of 832% and 969%, respectively. The electrohydrodynamic atomization process was employed in bimetallic systems containing chitosan to produce highly spherical microgels with a uniform size distribution. The surface texture of the microgels progressively transitioned from wrinkled to smooth as the concentration of Cu2+ ions increased. Nanometer-scale analysis of the bimetallic chitosan particles, across both types of chitosan, indicated a size range between 60 and 110 nanometers. FTIR spectroscopy supported the creation of complexes through physical interactions between the functional groups of the chitosan and the metal ions. A rise in the degree of deacetylation (DD) and copper(II) ion levels corresponds to a decrease in the swelling capacity of bimetallic chitosan particles, due to stronger complex formation with copper(II) ions relative to zinc(II) ions. Four weeks of enzymatic degradation did not compromise the stability of bimetallic chitosan microgels, and bimetallic systems with smaller copper(II) ion levels showcased good cytocompatibility with both varieties of chitosan employed.
To meet the escalating need for infrastructure, innovative, eco-friendly, and sustainable building techniques are currently under development, presenting a promising area of research. The creation of substitute concrete binders is crucial for reducing the environmental consequences associated with the use of Portland cement. Compared to Ordinary Portland Cement (OPC) construction materials, geopolymers, low-carbon and cement-free composite materials, show superior mechanical and serviceability properties. Base materials of industrial waste, high in alumina and silica content, combined with an alkali-activating solution binder, form these quasi-brittle inorganic composites. Appropriate fiber reinforcing elements can boost their inherent ductility. The analysis presented in this paper underscores the superior thermal stability, reduced weight, and diminished shrinkage properties of Fibre Reinforced Geopolymer Concrete (FRGPC), as demonstrated by past investigations. Accordingly, fibre-reinforced geopolymers are forecast to exhibit rapid innovation. This research encompasses a discussion of the history of FRGPC and the variability of its characteristics between the fresh and hardened states. Experimental evaluation and discussion of the moisture absorption and thermomechanical properties of lightweight Geopolymer Concrete (GPC), composed of Fly ash (FA), Sodium Hydroxide (NaOH), and Sodium Silicate (Na2SiO3) solutions, as well as fibers. Furthermore, the implementation of fiber-extension measures proves beneficial in improving the sustained shrinkage resistance of the instance. More fiber in a composite material frequently leads to a marked enhancement of mechanical properties, a distinction from the weaker responses exhibited by non-fibrous composites. This review study's results demonstrate FRGPC's mechanical properties, such as density, compressive strength, split tensile strength, and flexural strength, and its associated microstructural aspects.
This paper is dedicated to exploring the structural and thermomechanical attributes of PVDF-based ferroelectric polymer films. Transparent, electrically conductive ITO layers are applied to both sides of this thin film. Subjected to piezoelectric and pyroelectric effects, the material gains additional functional attributes, thereby forming a complete, flexible, and transparent device. For example, it produces sound when exposed to an acoustic stimulus, and, consequently, it generates an electrical signal under different external influences. CL316243 The presence of thermomechanical loads due to mechanical deformation and temperature effects during operation, or the use of conductive layers, is linked to the application of these structures. Employing IR spectroscopy, this article investigates the structural transformations of a PVDF film subjected to high-temperature annealing. Comparative testing before and after ITO layer deposition, incorporating uniaxial stretching, dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and transparency and piezoelectric property measurements, are further detailed. The results show that the temperature-dependent timing of ITO layer deposition has a negligible impact on the thermal and mechanical properties of PVDF films, considering their behavior in the elastic regime, although there is a subtle reduction in their piezoelectric properties. Simultaneously, the potential for chemical reactions between the polymer and ITO layers is evident.
The study seeks to explore the impact of different mixing methods, both direct and indirect, on the dispersal and evenness of magnesium oxide (MgO) and silver (Ag) nanoparticles (NPs) when incorporated into a polymethylmethacrylate (PMMA) substance. NP mixing with PMMA powder was executed directly and indirectly using ethanol as a solvent. Employing X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM), an evaluation of the dispersion and homogeneity of MgO and Ag NPs was conducted within the PMMA-NPs nanocomposite matrix. The prepared PMMA-MgO and PMMA-Ag nanocomposite discs were subjected to stereo microscopic analysis to characterize the dispersion and agglomeration. XRD measurements indicated a smaller average crystallite size of nanoparticles (NPs) within the PMMA-NP nanocomposite powder prepared using ethanol-assisted mixing compared to the method without ethanol. EDX and SEM analysis demonstrated improved distribution and consistency of both nanoparticles on the PMMA particles when employing ethanol-assisted mixing, exhibiting a marked difference from the non-ethanol-assisted method. The PMMA-MgO and PMMA-Ag nanocomposite discs, mixed with ethanol, presented a superior distribution and no clustering, in stark contrast to the discs mixed without ethanol. The addition of ethanol during the mixing process of MgO and Ag NPs with PMMA powder effectively improved the dispersion and homogeneity of the NPs, with no observable agglomeration in the composite.
Our paper scrutinizes natural and modified polysaccharides as active compounds within scale inhibitors, with a focus on mitigating scale formation in the contexts of petroleum extraction, heat transfer, and water provision. Processes for the modification and functionalization of polysaccharides effectively hindering the development of scale, composed of carbonates and sulfates from alkaline earth metals, encountered in technical procedures, are reported. This review analyzes the mechanisms of crystallization inhibition facilitated by polysaccharides, and explores the various methodologies for determining their effectiveness. The review furthermore encompasses the technological deployment of scale inhibitors, which are polysaccharide-based. Polysaccharides' industrial use as scale inhibitors necessitates a thorough investigation of their environmental impact.
Extensive cultivation of Astragalus in China produces Astragalus particle residue (ARP), which finds application as reinforcement for fused filament fabrication (FFF) biocomposites comprising natural fibers and poly(lactic acid) (PLA). A study of the degradation process of biocomposites involved the burial of 3D-printed 11 wt% ARP/PLA samples in soil, with subsequent investigation into how the duration of soil burial impacted their physical attributes, weight, resistance to bending, structural morphology, thermal stability, melting behavior, and crystallization properties. To serve as a point of comparison, 3D-printed PLA was chosen. Analysis revealed that the transparency of PLA decreased (though imperceptibly) with extended soil burial, whilst ARP/PLA samples displayed a graying surface speckled with black spots and crevices; a noticeably heterogeneous coloration was apparent in the samples after 60 days. Burial in soil caused a reduction in the weight, flexural strength, and flexural modulus of the printed samples, with the ARP/PLA samples experiencing more significant losses than those made from pure PLA. The soil burial duration's effect manifested as a gradual increase in glass transition, cold crystallization, and melting temperatures, and in enhancing the thermal stability of both PLA and ARP/PLA samples. Moreover, the thermal properties of ARP/PLA were more significantly altered by the soil burial method. Soil burial exerted a more substantial influence on the degradation profile of ARP/PLA, as evidenced by the findings compared to the behavior of PLA. The soil environment causes ARP/PLA to degrade at a more accelerated pace compared to the rate of PLA degradation.
The substantial advantages of bleached bamboo pulp, a natural cellulose, in terms of environmental protection and plentiful raw material availability, have propelled its prominence within the biomass materials field. CL316243 A green dissolution method for cellulose, applicable to the creation of regenerated cellulose materials, is provided by the low-temperature alkali/urea aqueous system. Bleached bamboo pulp, with its high viscosity average molecular weight (M) and high crystallinity, faces challenges when attempting to dissolve in an alkaline urea solvent system, restricting its practical implementation in the textile domain. By adjusting the sodium hydroxide and hydrogen peroxide ratio in the pulping process, a series of dissolvable bamboo pulps possessing appropriate M values were created, stemming from commercial bleached bamboo pulp displaying a high M value. CL316243 The reaction of hydroxyl radicals with cellulose's hydroxyl groups causes the molecular chains to be reduced in length. Subsequently, diverse regenerated cellulose hydrogels and films were developed by employing either an ethanol or a citric acid coagulation bath, and the influence of the bamboo cellulose's molecular weight (M) on the resulting material properties was meticulously studied. The mechanical performance of the hydrogel/film was noteworthy, displaying an M value of 83 104, and tensile strengths of 101 MPa and 319 MPa for the regenerated film and film, respectively.