Plasticizing Effect Research Articles

Feasibility of anaerobic co-digestion of biodegradable plastics with food waste, investigation of microbial diversity and digestate phytotoxicity

The effects of biodegradable plastics of different thicknesses (30 and 40 μm) and sizes (20 × 20, 2 × 2, and 1 × 1 mm) on anaerobic digestion of food waste and digestate phytotoxicity were investigated. Methane productions (38 days) for the groups with 20 × 20, 2 × 2, and 1 × 1 mm of 30 μm plastics were 92.46, 138.27, and 259.95 mL/gVSremoval, respectively which are nearly 58 % higher than the control group (58.86 mL/gVSremoval). Methane production in 40 μm plastics groups was lower than in 30 μm groups of equal size. All sizes of 30 µm plastics promoted substrate hydrolysis, acidification, and relative abundance of key hydrolytic bacteria and methanogens. Phytotoxicity tests results showed that seed root elongation was inhibited in groups with 40 μm plastics. In conclusion, 30 μm biodegradable plastics were more suitable for anaerobic digestion with food waste than 40 μm.

Strong room temperature work hardening in a dual heterogeneous structured ferrous medium entropy alloy

In this work, a novel (Fe65Ni15Cr10Co10)92Ti5Al3 medium-entropy alloy (MEA) with a dual heterogeneous structure was produced by adding Ti and Al in our previous reported Fe65Ni15Co10Cr10 MEA. The dual heterogeneous structure consists of the partial recrystallization matrix and heterogeneous nanoprecipitates. The tensile tests show that the MEA displays an ultra-high ultimate tensile strength (1519 MPa) and work hardening extent (559 MPa) at room temperature. The addition of Ti and Al produces precipitates while lowering FCC stability. This contributes to a continuous FCC→BCC martensitic transformation and a consequent transformation-induced plasticity (TRIP) effect during whole plastic deformation. Therefore, the excellent mechanical properties are attributed to the synergism of multiple mechanisms, including the hetero-deformation induced (HDI) strengthening, precipitation strengthening, and TRIP effects. The alloy design strategy in this paper has guiding significance for the development of high-performance ferrous MEAs.

Increased functional connectivity in the right dorsal auditory stream after a full year of piano training in healthy older adults

Learning to play an instrument at an advanced age may help to counteract or slow down age-related cognitive decline. However, studies investigating the neural underpinnings of these effects are still scarce. One way to investigate the effects of brain plasticity is using resting-state functional connectivity (FC). The current study compared the effects of learning to play the piano (PP) against participating in music listening/musical culture (MC) lessons on FC in 109 healthy older adults. Participants underwent resting-state functional magnetic resonance imaging at three time points: at baseline, and after 6 and 12 months of interventions. Analyses revealed piano training-specific FC changes after 12 months of training. These include FC increase between right Heschl’s gyrus (HG), and other right dorsal auditory stream regions. In addition, PP showed an increased anticorrelation between right HG and dorsal posterior cingulate cortex and FC increase between the right motor hand area and a bilateral network of predominantly motor-related brain regions, which positively correlated with fine motor dexterity improvements. We suggest to interpret those results as increased network efficiency for auditory-motor integration. The fact that functional neuroplasticity can be induced by piano training in healthy older adults opens new pathways to countervail age related decline.

Heterogeneous distribution of isothermal ω precipitates prevents brittle fracture in aged β-Ti alloys

Isothermal ω (ωiso) precipitates in β Ti-alloys can increase the yield strength of the material, but unfortunately at a dramatic cost of the ductility. The embrittlement is mainly attributed to the suppression of twinning-induced plasticity (TWIP) and transformation-induced plasticity (TRIP) effects, as well as the formation of dislocation channels associated with localized deformation. To address this issue, we propose a heterogenous microstructure in Ti-15Mo-3Al alloy using conventional rolling method, in which the heterogeneous distributions of both Mo element and ωisoprecipitates are realized after aging. Both the nano-hardness and elastic modulus of ωisorich (Mo-lean) regions are larger than that of ωisodepleted (Mo-rich) regions. A four-time increase in tensile ductility is achieved in the heterogeneous microstructure without a loss of tensile strength, compared with the homogeneous counterpart. The ductility improvement can be ascribed to the blocking effect of ωisodepleted regions against the propagation of dislocation channels which later evolve into micro-cracks.

The evidence of in-vivo and in-vitro studies on microplastic and nano plastic toxicity in mammals: A possible threat for an upcoming generation?

Plastic pollution is a pressing global environmental concern, exerting significant impacts on both aquatic and terrestrial ecosystems in recent decades. The detrimental effects of plastic on various species within these habitats have raised serious alarm. Regrettably, human exposure to microplastics (MPs) and nanoplastics (NPs) through contaminated food has become unavoidable, but the comprehensive extent of their consequences remains largely unexplored. This review aims to advance existing research and conduct a comprehensive evaluation of current studies pertaining to the potential toxicity and negative impacts of micro- and nano-plastics on soil, water, and land, with a specific focus on their implications for human health. Through meticulous examination of the existing literature, we aim to provide a succinct overview of the potential risks associated with micro and nano plastics, thereby guiding and emphasizing the direction for future research in this domain and addressing critical knowledge gaps. The study underscores that extant research has established a clear association between micro and nano plastics and their adverse effects on the digestive system, cell lines, and reproductive health. Nevertheless, deeper investigations are imperative to achieve a better understanding of the cellular, molecular, neurological, and systemic toxicity caused by these minute plastic particles. Information presented in the review provides a scientific understanding of the hazards posed by micro and nano plastics to both the environment and human health is essential for formulating effective mitigation strategies and regulatory measures.

A review on photochemical effects of common plastics and their related applications

AbstractThe photochemical effects of plastics refer to a series of photochemical reactions of plastics under certain illumination conditions. In order to help researchers understand the research progress of photochemical effects of plastics, we will introduce photochemical effects of seven common plastics and discuss the influence of functional groups of polymers in plastics on the photochemical effects of plastics in this review. Based on this, we discuss the impact of photochemical effects on the properties of plastics and some factors affecting the surface photochemical effects of plastics. Last but not least, although in most cases the photochemical effects of plastics are extremely detrimental to the control of plastic pollution, some applications based on the photochemical effects of plastics will also be introduced in this review. It is believed that this review can provide some new ideas for the development of new and clean processes and some promising materials such as light‐responsive materials.

Deciphering the Effect of Microstructural Modification in Sodium Alginate-Based Solid Polymer Electrolyte by Unlike Anions.

Microstructure modification in sodium alginate (NaAlg)-based solid polymer electrolytes by the perchlorate (ClO4-) and acetate (CH3COO-) anions of sodium salts has been reported. ClO4- participates in the structure-breaking effect via inter/intramolecular hydrogen bond breaking, while CH3COO- changes the amorphous phase, as evident from X-ray diffraction studies. The larger size and negative charge delocalization of ClO4- have a plasticizing effect, resulting in a lower glass transition temperature (Tg) compared to CH3COO-. Decomposition temperature is strongly dependent on the type of anion. Scanning electron microscopy images showed divergent modifications in the surface morphology in both electrolyte systems, with variations in salt content. The mechanical properties of the NaAlg-NaClO4 electrolyte systems are better than those of the NaAlg-CH3 COONa system, indicating weak interactions in the latter. Although most of the studies focus on the cation influence on conductivity, the interaction of the anion and its size certainly have an influence on the properties of solid polymer electrolytes, which will be of interest in the near future for sodium ion-based electrolytes in energy storage devices.

The impacts of synthetic and cellulose-based fibres and their associated dyes on fish hosts and parasite health

Plastic pollution is now a ubiquitous feature of freshwater systems and the majority of this is fibrous. Here, we test the effects of plastic and cellulose-based fibres (polyester, cotton, and bamboo from commercial clothing) on fish host-parasite interactions using a freshwater fish host-parasite model system (guppy Poecilia reticulata-Gyrodactylus turnbulli). For uninfected fish, polyester exposure was associated with significantly higher mortality rates compared with the other two fibre types. For infected fish, whilst polyester and cotton exposure were not associated with any significant changes to parasite burdens, fish exposed to bamboo fibres had significantly reduced maximum parasite burdens compared with fish not exposed to any fibres, indicating that the bamboo fibres and/or associated dyes conferred some degree of resistance or tolerance. Whilst unable to determine the exact nature of the chemical dyes, when testing off-host parasite survival on exposure to the fibre dyes, cotton and particularly polyester dyes were associated with higher parasite mortality compared to bamboo. Overall, we add to the growing body of evidence which shows that polyester microplastic fibres and their associated dyes can be detrimental for both fish and parasite survival, and we highlight the need for increased transparency from textile industries on the chemical identity of fabric dyes.

Properties of Eco-Friendly Composites Based on Post-Consumer Recycled Resin Filled with Walnut Shell Powder.

Increased demand for environmentally friendly materials resulted in a worldwide interest in manufacturing composite materials from agricultural wastes. Thus, this paper presents the results of research on the synthesis of eco-friendly composites and their properties. For their preparation, unsaturated polyester resin based on post-consumer recycled poly (ethylene terephthalate) was filled with walnut (Júglans régia L.) shell powder. After the filler incorporation, the deterioration of gloss and mechanical properties were observed. The flexural strength and modulus are significantly affected by the filler amount. Distilled water, 1% sodium hydroxide, toluene, and acetone were used as solvents in the chemical resistance test. Changes to the structure and properties of composites after 49 days of immersion in solvents were investigated. The immersion in water has no significant effect on the pure resin, but for its composites, the plasticizing effect of water was observed. The results show that all specimens show resistance toward toluene. In acetone, the resin and its composite shrink and fall into pieces, but the most destructive is an alkaline environment. After the immersion test, a huge increase in mass and a deterioration of gloss and mechanical properties were observed.

Plasticizer concentration effect on films and coatings based on poly(vinyl alcohol) and cationic starch blends

Films based on poly(vinyl alcohol) (PVA) and cationic starch (CS) were combined with different percentages of sorbitol (S; 15.0, 22.5, and 30.0% w v-1) to assess the effect of plasticizer on the films. Spectroscopic analyses confirmed the interaction between them. However, micrographs indicated the formation of sorbitol crystals on the surface of the films, especially at higher sorbitol concentrations. The blends presented low water vapor transmission rate values, reaching (7.703 ± 0.000) g h−1 m−2 (PVA75CS25S15), and low solubility values for the films containing higher CS amounts. The lack of statistical differences in most parameters suggests that no significant gain comes from increasing the amount of sorbitol at percentages higher than 15%. As a coating, the blend PVA75CS25S15 successfully decreased the loss of moisture content in acerolas by 1.15 times (compared to the control), confirming the suitability of this matrix as a fruit coating.

Quantification of hygrothermal aging-induced interfacial debonding of carbon fiber/epoxy composites at nano-to-micrometer length scales

This work investigated the phenomenon of interfacial debonding due to hygrothermal aging (HA), which was quantified using Field Emission Scanning Electron Microscopy (FESEM) and Atomic Force Microscopy (AFM). Several micrographs of carbon fiber/epoxy cross-ply laminate coupons were analyzed, including unaged (HA/0) samples, as well as those aged for 1000 h (HA/1000) and 2000 h (HA/2000). To quantify the extent of debonding, an image thresholding tool was employed. For HA/0, HA/1000, and HA/2000 coupons, the average interfacial debonding arc length of inner plies was longer than that of the respective outer plies by 14%, 17%, and 21%, respectively. Residual stress variation across inner plies is more pronounced compared to outer plies due to the latter's freedom of expansion. The debonding that occurred without external loading was due to the combined effects of matrix and interface plasticization, chemical reaction, viscoelastic changes, and swelling. The AFM 3-D surface topography revealed that HA/0, HA/1000, and HA/2000 specimens had progressively lower peak-valley distances of 135 nm, 113 nm, and 82 nm, respectively, due to matrix swelling.

Channels formation in cellulose materials by accelerated transport of gas molecules and glycerin

In this study, a microporous separator was produced using cellulose acetate (CA), which demonstrates heightened thermal stability in comparison to existing materials like polypropylene (PP) or polyethylene (PE). Furthermore, a pliable component was integrated into the CA membrane using glycerin as the plasticizing agent. Subsequently, gas pressure was exerted onto these areas to induce the formation of nano-sized pores. Examination through Scanning Electron Microscopy (SEM) unveiled the presence of abundant pores in the glycerin-plasticized areas. This substantiates that the pores generated under gas pressure were not only more uniform but also smaller than those created under water pressure. The interaction between CA and glycerin was validated using Fourier-Transform Infrared Spectroscopy (FT-IR), offering confirmation that a portion of the glycerin was extracted following the application of gas pressure. Additionally, the application of Thermogravimetric Analysis (TGA) allowed for an assessment of the thermal stability of the CA membrane, along with a verification of glycerin's removal post gas pressure treatment. The findings indicated that the incorporation of glycerin diminished the thermal stability of the CA membrane due to the plasticization effect. Furthermore, it was observed that a minor quantity of glycerin still persisted after the gas pressure treatment. Following the analysis of gas permeation, the porosity of the CA membrane was quantified at 78.8 %, exhibiting an average pore size measuring 224 nm.

RESEARCHING THE INFLUENCE OF PLASTICIZERS ON THE TECHNOLOGICAL AND PHYSICAL-MECHANICAL PROPERTIES OF COMPOSITE BINDING SUBSTANCES OF THE СаО – Al2O3 – SO3 – H2O SYSTEM

Problem statement. Composition of modern concretes and mortars includes surface-active substances that regulate processes of hydration, structure formation and, accordingly, properties of artificial stone. One of the types of surface-active substances are plasticizers, their main purpose is to reduce water consumption. When considering their influence, a wider range of changes in the properties of solutions and concretes can be noted. In this regard a particular attention should be paid to aluminate, sulfate and sulfo-aluminate binders. Therefore, the development of composite binders of the CaО – Al2O3 – SO3 – H2O system based on alumina cement and gypsum with the use of plasticizers requires research in this direction. The purpose of the article – to investigate the effect of plasticizers on the technological and basic physical and mechanical properties of alumina cement and composites based on it. Conclusions. A complex of experimental and statistical models of nanomodified compositions based on alumina cement and gypsum was obtained, and these models make it possible to determine influence of input factors on the growth of the main physical and mechanical properties. Research has established the ratio of the basic components of the composite based on 70 % alumina cement, 30 % gypsum and Sika VG Sika plasticizer = 0.10 ÷ 0.40; alumina cement = 69.72 ÷ 69.93; Gypsum = 29.88 ÷ 29.97. According to the manufacturing technology, the number of components was reduced to a minimum and a binder-filler-plasticizer system was obtained. From the economic point of view, depending on the customer’s requirements, it is possible to regulate the consumption of alumina cement and gypsum binder within the limits of approximately 10 %.

Effects of ZnO nanoparticles, polyethylene glycol 400, and polyoxyethylene sorbitan ester Tween 80 on PLA films properties

Abstract Polylactic acid has the potential to be an alternative to petroleum-based materials in the food packaging industry. In this study, the effect of zinc oxide nanoparticles, polyethylene glycol 400, and Tween 80 as plasticizers on the properties of polylactic acid films was investigated. In order to study the mechanical properties more accurately, the tests were repeated for four months. An experimental design method was used to investigate the effects of additives on the measurement factors and finally to choose the optimal combination with the help of the TOPSIS technique. The results showed that the addition of different materials increased the opacity, most of which being related to P400/ZnO (6.82 ± 0.07 mm−1). The presence of plasticizers increases the hydrophilicity of the film and the water vapor permeability. The highest contact angle (85.33° ± 4.00) and the lowest water vapor permeability (0.074 ± 0.002 g mm/kPa h m2) were related to neat PLA film. The lowest modulus of elasticity, the highest tensile strength and elongation at break were related to P400/T80/ZnO (1.18 ± 0.17 GPa, first month), PLA/ZnO (96.28 ± 3.17 MPa, fourth month), and P400/ZnO (76.82 ± 27.22 %, first month), respectively. The effect of plasticizers was significant in most of the measurement factors, but the effect of nanoparticles was significant in some cases such as opacity and contact angle. The results of an ANOVA analysis showed that the effect of film type on the mechanical properties was significant, and the effect of storage time was only significant on the elongation at break. According to the results obtained from the TOPSIS technique, P400/ZnO was chosen as the combination with the best features among the produced films.

Rapid evolution of phenotypic plasticity in patchy habitats

Phenotypic plasticity may evolve rapidly, enabling a population’s persistence in the face of sudden environmental change. Rapid evolution can occur when there is considerable genetic polymorphism at selected loci. We propose that balancing selection could be one of the mechanisms that sustain such polymorphism for plasticity. We use stochastic Monte Carlo simulations and deterministic analysis to investigate the evolution of a plasticity modifier locus in structured populations inhabiting favorable and adverse environments, i.e. patchy habitats. We survey a wide range of parameters including selective pressures on a target (structural) locus, plasticity effects, population sizes, and migration patterns between demes including periodic or continuous bidirectional and source-sink dynamics. We find that polymorphism in phenotypic plasticity can be maintained under a wide range of environmental scenarios in both favorable and adverse environments due to the balancing effect of population structure in patchy habitats. This effect offers a new plausible explanation for the rapid evolution of plasticity in nature: Phenotypic plasticity may rapidly evolve from genetic variation maintained by balancing selection if the population has experienced immigration from populations under different selection regimes.

Strengthening mechanisms and microstructural evolution of medium manganese steel under dynamic and static loading

The study analyzes the deformation strengthening mechanisms of medium manganese steel under dynamic and static loading conditions. Different austenite volume fractions (7.4 %, 19.1 %, 30.9 %, 37.7 %) were obtained by varying the heat treatment temperatures (640 °C, 660°C, 680 °C, 700 °C). Results show a linear increase in austenite volume fraction with higher annealing temperature, while carbon content in austenite decreases. Yield strength initially decreases and then increases with annealing temperature. The mechanical properties of all four temperature-tested steels show a clear strain rate dependence in the high strain rate range, with strength increasing with strain rate. Quasi-static conditions no significant strain rate sensitivity. 680 °C test steel's quasi-static deformation is mainly governed by the transformation-induced plasticity (TRIP) effect and dislocation slip in body-centered cubic (bcc) crystals. Dynamic deformation after a strain of 0.14 shows a weakened TRIP effect, and dislocation strengthening in bcc crystals becomes dominant despite a large amount of untransformed austenite. During quasi-static deformation, 700 ℃ test steel exhibits strain hardening due to the TRIP effect at low strains and significant dislocation strengthening in bcc crystals at high strains. Although the TIRP effect is initially suppressed during dynamic deformation, it lasts for a long time. The combined effects of the TRIP effect and martensite dislocation strengthening determine the deformation strengthening mechanisms. Additionally, an optimized Voce model with strain rate strengthening term is proposed. It can well describe the mechanical behavior under dynamic strain rate.

Asphaltenes from Heavy Crude Oil as Ultraviolet Stabilizers against Polypropylene Aging.

The destruction of polymers under the influence of ultraviolet (UV) radiation is the cause of their aging and deterioration of strength properties. Asphaltenes are low-value waste products after the refining and deasphalting of heavy crude oil, which absorb UV radiation well. Asphaltenes require rational utilization, which suggests their use as UV stabilizing agents for polymers. In this work, asphaltenes were used to prevent UV aging of polypropylene (PP) by adding them in a mass fraction from 5% to 30% within an asphaltene/PP composite material. Rheometry, calorimetry, X-ray diffraction analysis, and tensile strength of PP films containing asphaltenes were performed before and after their intense UV irradiation for accelerated aging. Asphaltenes slightly reduce the viscosity, crystallinity, and mechanical strength of the initial PP due to their plasticizing effect. However, this deterioration in properties is more than compensated when studying UV-aged samples. Intense UV aging causes multiple catastrophic drops in the viscosity and strength of pure PP with the preservation of crystallinity due to the break of polymer chains and a decrease in molecular weight by approximately eight times. Asphaltenes suppress the destruction of PP, which is expressed in a significantly smaller decline in its viscosity and strength due to UV aging. The most optimal content of asphaltenes is 20%, which suppresses UV destruction by six times and best preserves the strength properties of PP.

Fabrication of bioplastic material based on ethyl-cellulose using hot-melt extrusion

Ethyl-cellulose (EC) was used for thermal fabrication of bioplastic materials using hot-melt extrusion. Plasticizers were chosen based on compatibility analysis using Hansen Solubility Parameters theory. The thermal analysis showed lower Tg and Tm values for all samples, suggesting the extrusion process, as well as plasticizer addition, affected the polymer thermal behavior. Myvacet® (acetylated monoglycerides) had the most significant effect, decreasing the Tg from 128.73 ± 0.83 to 113.52 ± 0.36 ℃ and the Tm from 178.41 ± 0.79 to 166.66 ± 0.64 ℃. Overall, all plasticizers led to thermoplastic mechanical behavior characterized by elastic and plastic deformations, as opposed to the solely elastic behavior of the neat EC films, confirming the plasticizing effect. Moreover, the plasticized films exhibited significantly higher tensile strength and percent of elongation at break, resulting in stronger and more flexible films. EC-based films exhibit high permeability to oxygen and relatively high water vapor transmission rate (∼100 g/m2day at 38 ℃ and 90% RH) which signifies EC suitability as packaging material for fresh produce.

Whole brain network effects of subcallosal cingulate deep brain stimulation for treatment-resistant depression

Ongoing experimental studies of subcallosal cingulate deep brain stimulation (SCC DBS) for treatment-resistant depression (TRD) show a differential timeline of behavioral effects with rapid changes after initial stimulation, and both early and delayed changes over the course of ongoing chronic stimulation. This study examined the longitudinal resting-state regional cerebral blood flow (rCBF) changes in intrinsic connectivity networks (ICNs) with SCC DBS for TRD over 6 months and repeated the same analysis by glucose metabolite changes in a new cohort. A total of twenty-two patients with TRD, 17 [15 O]-water and 5 [18 F]-fluorodeoxyglucose (FDG) positron emission tomography (PET) patients, received SCC DBS and were followed weekly for 7 months. PET scans were collected at 4-time points: baseline, 1-month after surgery, and 1 and 6 months of chronic stimulation. A linear mixed model was conducted to examine the differential trajectory of rCBF changes over time. Post-hoc tests were also examined to assess postoperative, early, and late ICN changes and response-specific effects. SCC DBS had significant time-specific effects in the salience network (SN) and the default mode network (DMN). The rCBF in SN and DMN was decreased after surgery, but responder and non-responders diverged thereafter, with a net increase in DMN activity in responders with chronic stimulation. Additionally, the rCBF in the DMN uniquely correlated with depression severity. The glucose metabolic changes in a second cohort show the same DMN changes. The trajectory of PET changes with SCC DBS is not linear, consistent with the chronology of therapeutic effects. These data provide novel evidence of both an acute reset and ongoing plastic effects in the DMN that may provide future biomarkers to track clinical improvement with ongoing treatment.

Research progress on the interference effects of plasticizers on maternal behavior and its potential mechanisms.

Environmental endocrine disrupting chemicals (EDCs), known as environmental hormones, are exogenous chemicals that can disrupt hormone levels and cause dysfunction of the secretory system in humans and animals. Plasticizers, which are widely used EDCs, are commonly used to enhance the flexibility of plastic products. As plastics age and wear, however, they can leach into the environment and enter the bodies of animals through various pathways such as the digestive tract and skin. They can lead to estrogen-like effects and have substantial reproductive toxicity. Residual plasticizer concentrations in the environment are typically low. Unlike high doses that induce acute damage to the reproductive system, low doses of plasticizers do not cause macroscopic harm and thus its reproductive toxicity is often overlooked for extended periods. An increasing number of studies conducted on humans and mice in recent years have demonstrated that low doses of plasticizers can induce reproductive toxicity by interfering with maternal behavior. Prenatal exposure to plasticizers can result in abnormal postnatal maternal behavior. Female offspring also exhibit significantly low maternal care, lactation, and other behaviors in adulthood, which may persist for multiple generations, significantly disrupting the animal breeding process and impacting the health and well-being of newborn pups. The underlying mechanisms have not been systematically summarized. The risk of continuous exposure to low-dose plasticizers in humans and animals has increased due to the extensive utilization of plastic and rubber products in modern production and lifestyle patterns. It is thus crucial to conduct a systematic review on the effects of low-dose plasticizers on maternal behavior. We reviewed the research progress on the disruptive effects of plasticizers on animals' maternal behavior and concluded that these effects are primarily caused by inducing oxidative stress damage and DNA methylation reprogramming in the hypothalamic-pituitary-ovarian axis, as well as disrupting the balance of the thyroid system and causing intestinal microbial disorders. It would offer a novel perspective for future studies about the influence of plasticizers and other environmental hormones on maternal behavior in domesticated animals.