The deficiencies of popular phthalate plasticizers(ready migration from a polymer matrix into which they have been incorporated,flammability,environmental pollution,human health risks)have stimulated efforts to develo...The deficiencies of popular phthalate plasticizers(ready migration from a polymer matrix into which they have been incorporated,flammability,environmental pollution,human health risks)have stimulated efforts to develop new effective,nonmigrating,low-cost,nontoxic replacements.In the main,these have been based on readilyavailable,nontoxic biobased precursors.Some,including those prepared from plant oils,have been generated from biomaterials themselves.However,the more numerous and generally more effective have been generated from discrete compounds produced from various biomaterials.Several structural features of effective plasticizers have been recognized.Polar functionality is required to assure compatibility with a wide range of polymeric materials,including poly(vinyl chloride)(PVC),the most heavily plasticized polymer.A branched structure greatly enhances the effectiveness of compounds used as plasticizers.An oligomeric structure may strongly limit or prevent migration from a polymer matrix.Hyperbranched oligomers of defined structure derived from the readilyavailable,inexpensive,nontoxic biomonomers,glycerol and adipic acid contain all these features and are excellent plasticizers.They contain ester functionality,are highly branched,and display a large number of end groups,all of which contribute to their effectiveness as plasticizers.展开更多
Cellulose acetate(CA)is an important cellulose derivative that can undergo thermoplas-tic processing.Plasticizers can form stable hydrogen bonds with CA molecular chains,reducing intermolecular and intramolecular inte...Cellulose acetate(CA)is an important cellulose derivative that can undergo thermoplas-tic processing.Plasticizers can form stable hydrogen bonds with CA molecular chains,reducing intermolecular and intramolecular interactions,and play an important role in the melting processing of CA.In recent years,environmentally friendly plasticizers that are natural,non-toxic,odorless,low dissolution,and low migration have received increas-ing attention in plastic processing.This article reviews the research progress of environ-mentally friendly plasticizers such as natural plasticizers,ionic liquid plasticizers,citrate plasticizers,and polyethylene glycol plasticizers in the processing of cellulose acetate,and looks forward to the application prospects of environmentally friendly plasticizers.展开更多
The effects of plasticizers,antioxidants and burning rate modifiers on the aging performance of the composite solid propellant based on hydroxyl-terminated polybutadiene(HTPB)/hexamethylene diisocyanate(HMDI)were expl...The effects of plasticizers,antioxidants and burning rate modifiers on the aging performance of the composite solid propellant based on hydroxyl-terminated polybutadiene(HTPB)/hexamethylene diisocyanate(HMDI)were explored by apply-ing an accelerated aging program for 90 day at 70 ℃. The HTPB propellant matrix with the diisooctyl sebacate(DOS)as plasti-cizers and diisooctyl azelate(DOZ), antioxidants as N,N ′-Diphenyl-p-phenylenediamine(AO) and 2,2′-methylenebis(4-methyl-6-tert-butylphenol)(cyanox 2246)and burning rate modifiers as barium ferrite(BF),copper chromites(CC)and fer-ric oxide(FO)were varied. Results show that sample(S1)which based on DOS decreases the stress value and increases the strain value which considered to be an excellent start for aging program. Sample(S3)containing AO presents the higher resis-tance to oxidation showing the better performance that reflects on increasing the shelf life of the composite solid propellant mo-tor. Sample(S5)which based on BF enhances the ballistic performance among over the other tested two samples. The accelerat-ed aging program allowed us to estimate the motor in-service lifetime.展开更多
This aim of this work is to study the partial replacement of the plasticizer ordinarily used di-octyl phtalate (DOP) by the permanent plasticizers ethylene-vinyl-acetate (EVA) and acrylonytrile-bu- tadiene-styrene (AB...This aim of this work is to study the partial replacement of the plasticizer ordinarily used di-octyl phtalate (DOP) by the permanent plasticizers ethylene-vinyl-acetate (EVA) and acrylonytrile-bu- tadiene-styrene (ABS) in order to reduce migration of additives initially contents in polyvinyl chloride (PVC) stabilized with expoxidized sunflower oil (ESO). Migration tests with agitation to 40°C in sunflower oil and ethanol at 15% were made. Migration phenomenon was studied on the basis of the PVC samples mass variations, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) analysis. The results showed the effectiveness of the approach consisting in the partial substitution of DOP by plasticizers of polymeric nature. The following order concerning the migration of additives was found: DOP (40) > DOP:EVA > (30/10) DOP:ABS (30/10). Furthermore, all the measured values of overall migrations were lower than the maximum allowable overall migration: 10 mg-dm-2.展开更多
The inhibition and its mechanism of sodium tripolyphosphate （STP） composited with super plasticizers （SPs） on hydration of α-calcium sulfate hemihydrate were studied by setting time, strength, hydration heat, X-r...The inhibition and its mechanism of sodium tripolyphosphate （STP） composited with super plasticizers （SPs） on hydration of α-calcium sulfate hemihydrate were studied by setting time, strength, hydration heat, X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, electronic probe micro analysis （EPMA）, scanning electron microscopy （SEM） and differential scanning calorimeter （DSC） measurements. The experimental results show that compared with STP addition, compositing STP with polycarboxylate （PC） plasticizer, the final setting time is prolonged from 0.5h to 2hs. While formulating STP with naphthalene-based plasticizer （NAP） or sulfonate melamine formaldehyde plasticizer （SMF）, the final setting time is reduced to quarter of an hour. Similar changes can also be found in the rate of exothermic hydration and hydration degree. Formulating STP with suitable addition of PC can enhance the strength, while compositing STP and NAP or SMF weakens the strength. Besides, adding STP or STP and SMF, obvious movement （more than 1ev） of binding energy of Ca2p1/2 and Ca2p3/2 is detected. Compared with STP addition, content of the characteristic element （P） of STP is cut down form 1.1% to 0.49% by compositing STP with SMF. Furthermore, as hydration age increases, hydration inhibition in the presence of admixtures weakens and even disappears within 56 h.展开更多
Geminal dinitropropyl ester plasticizers(DNPEPs) possess excellent energetic performances which provide good potentials as insensitive plasticizer. In this study, we design and synthesize DNPEPs with different alkane ...Geminal dinitropropyl ester plasticizers(DNPEPs) possess excellent energetic performances which provide good potentials as insensitive plasticizer. In this study, we design and synthesize DNPEPs with different alkane chain parts, and systematically investigate their structure-property relationships.Results show that DNPEPs have impact sensitivities all higher than 25.2 J, thermal decomposition temperatures all higher than 254 ℃, and glass transition temperatures(T_(g)) lower than-90 ℃.Furthermore, the effects of DNPEPs as plasticizer are studied on hydroxyl terminated polybutadiene(HTPB) in detail, including the viscosity, glass transition temperatures and others. It is noteworthy that 2,2-dinitropropyl nonanoate(DNPNc) among these DNPEPs exhibits the most expected simultaneous tuning effects on both viscosity and T_(g) of HTPB systems, providing favorable potentials to replace the conventional plastizers as dioctyl sebacate(DOS) in the HTPB based propellants and explosives.展开更多
Ethylene glycol, glycerol, sorbitol, formamide, and urea were used as plasticizers for the preparation of thermoplastic starch（TPS） from corn starch. The properties of TPS were tested by analysis method. The results...Ethylene glycol, glycerol, sorbitol, formamide, and urea were used as plasticizers for the preparation of thermoplastic starch（TPS） from corn starch. The properties of TPS were tested by analysis method. The results showed that TPSs were more highly plasticized with amines than alcohols. For the same type of plasticizer, the degree of plasticization decreased as the molecular weight of plasticizer increased. The relationship between plasticization degree and TPS properties was characterized and described by mechanical properties and water absorption. The experimental results showed that when the degree of plasticization increased, the tensile strength decreased and the elongation at breakage and water absorption increased.展开更多
In order to improve the properties of rice straw fiber film, one factor contrast test method was employed. Plasticizer type was chosen as input variable, dry tension strength and elongation, wet tension strength and e...In order to improve the properties of rice straw fiber film, one factor contrast test method was employed. Plasticizer type was chosen as input variable, dry tension strength and elongation, wet tension strength and elongation, bursting strength and tearing strength were chosen as indexes. The results showed that there were significant differences among the means of dry tension strength, dry elongation and bursting strength of different plasticizers; there were not significant differences among the means of wet tension strength, wet elongation and tearing strength of different plasticizers; for dry tension strength and elongation, glycerol had a significant difference with sorbitol and PEG, no significant difference was observed between sorbitol and PEG, dry tension strength added glycerol had been reduced 6.8% compared with that added sorbitol, reduced 9.5% compared with that added PEG; elongation had been improved 6.1% and 9.4%, respectively; for bursting strength, sorbitol had a significant difference with glycerol and PEG, no significant difference was observed between glycerol and PEG; bursting strength added glycerol and added PEG had been improved 6.9% and 5.6%, respectively compared with that of the added sorbitol. The results provided a theoretical reference for further improving the straw fiber film manufacturing process.展开更多
The effects of glycerol and sorbitol as two plasticizers on mechanical properties, water vapor permeability, thermal properties, color and capability of heat sealing of gelatin films (of phytophagous fish, bovine gela...The effects of glycerol and sorbitol as two plasticizers on mechanical properties, water vapor permeability, thermal properties, color and capability of heat sealing of gelatin films (of phytophagous fish, bovine gelatin with high gel-forming ability, and bovine gelatin with low gel-forming ability) containing clay nanoparticles were studied in this research. For this purpose, 6 × 2 × 3 factorial experiments using the completely randomized design and comparison of the means at 95% confidence level (α = 0.05) were performed. Higher concentrations of plasticizers increased percentage elongation to the breaking point. When glycerol concentration was raised to over 20%, flexibility of the layers improved but their water vapor permeability increased. The minimum passage of water vapor was that of fish-skin gelatin films containing clay nanoparticles and 30% sorbitol, and the maximum that of bovine gelatin films with high gel-forming ability which contained nanoparticles but no plasticizers (p 0.05). All samples had heat sealing capability, and fish-skin gelatin films containing clay nanoparticles had better heat sealing capability compared with the other samples so that fish-skin gelatin films containing clay nanoparticles with 25% glycerol and 5% sorbitol had the highest flexibility and tensile strength, and remained attached to where they were heat sealed. Electron microscope images showed that films without plasticizers had uniform surfaces, but that samples containing glycerol at concentrations of over 0.20 g/g gelatin exhibited cavities between gelatin chains and that water vapor permeability in gelatin films containing clay nanoparticles.展开更多
Numerous studies reported risk assessment of human exposure to plasticizers in toys through dermal pathways,however,dermal bioaccessibility and percutaneous penetration of plasticizers under effects of lead had been s...Numerous studies reported risk assessment of human exposure to plasticizers in toys through dermal pathways,however,dermal bioaccessibility and percutaneous penetration of plasticizers under effects of lead had been seldom studied.In the present study,dermal bioaccessibility of plasticizers including phthalate esters and alternative plasticizers in toys were examined in artificial sweat and SSSM(synthetic sweat and sebum mixture),and percutaneous penetration of plasticizers were investigated by skin cells under individual plasticizers exposure or combined exposure conditions(plasticizers t lead).The present results indicated that dermal bioaccessibility of plasticizers in SSSM were higher than that in artificial sweat.DEHP(Di-2-ethylhexyl Phthalate)showed highest bioaccessibility among all the plasticizers,DEHT(Di(2-ethylhexyl)terephthalate)showed highest bioaccessibility among all the alternative plasticizers.DEHP and DEHT were selected to perform the cell absorption assay.Skin cell absorption assay demonstrated that MEHP(Mono-(2-ethylhexyl)phthalate)was the major metabolite of DEHP and the absorption percentage of DEHP was higher than that of DEHT.Compared to individual exposure of plasticizers,the absorption percentage of DEHP and DEHT in skin cells under the combined exposure condition were increased by 12.40%e14.63%and 8.35%e9.84%,respectively.Risk assessment indicated that the plasticizers in toy would not result in unacceptable risk for children,but the health risk of plasticizers in toys to children under combined exposure condition would be 1.5e2 times higher than that under individual exposure condition.展开更多
There is growing concern about the concept that exposure to environmental chemicals may be contributing to the obesity epidemic.However,there is no consensus on the obesogenic effects of emerging contaminants from a t...There is growing concern about the concept that exposure to environmental chemicals may be contributing to the obesity epidemic.However,there is no consensus on the obesogenic effects of emerging contaminants from a toxicological and environmental perspective.The potential human exposure and experimental evidence for obesogenic effects of emerging contaminants need to be systematically discussed.The main objective of this review is to provide recommendations for further subsequent policy development following a critical analysis of the literature for humans and experimental animals exposed to emerging contaminants.This article reviews human exposure to emerging contaminants(with a focus on antimicrobials,preservatives,water and oil repellents,flame retardants,antibiotics and bisphenols)and the impact of emerging contaminants on obesity.These emerging contaminants have been widely detected in human biological samples.Epidemiological studies provide evidence linking exposure to emerging contaminants to the risks of obesity in humans.Studies based on animalmodels and adipose cells show the obesogenic effects of emerging contaminants and identify modes of action by which contaminants may induce changes in body fat accumulation and lipid metabolic homeostasis.Some knowledge gaps in this area and future directions for further investigation are discussed.展开更多
Spinal cord injury necessitates effective rehabilitation strategies, with exercise therapies showing promise in promoting recovery. This study investigated the impact of rehabilitation exercise on functional recovery ...Spinal cord injury necessitates effective rehabilitation strategies, with exercise therapies showing promise in promoting recovery. This study investigated the impact of rehabilitation exercise on functional recovery and morphological changes following thoracic contusive spinal cord injury. After a 7-day recovery period after spinal cord injury, mice were assigned to either a trained group(10 weeks of voluntary running wheel or forced treadmill exercise) or an untrained group. Bi-weekly assessments revealed that the exercise-trained group, particularly the voluntary wheel exercise subgroup, displayed significantly improved locomotor recovery, more plasticity of dopaminergic and serotonin modulation compared with the untrained group. Additionally, exercise interventions led to gait pattern restoration and enhanced transcranial magnetic motor-evoked potentials. Despite consistent injury areas across groups, exercise training promoted terminal innervation of descending axons. In summary, voluntary wheel exercise shows promise for enhancing outcomes after thoracic contusive spinal cord injury, emphasizing the role of exercise modality in promoting recovery and morphological changes in spinal cord injuries. Our findings will influence future strategies for rehabilitation exercises, restoring functional movement after spinal cord injury.展开更多
Peripheral nerve injuries result in the rapid degeneration of distal nerve segments and immediate loss of motor and sensory functions;behavioral recovery is typically poor.We used a plasmalemmal fusogen,polyethylene g...Peripheral nerve injuries result in the rapid degeneration of distal nerve segments and immediate loss of motor and sensory functions;behavioral recovery is typically poor.We used a plasmalemmal fusogen,polyethylene glycol(PEG),to immediately fuse closely apposed open ends of severed proximal and distal axons in rat sciatic nerves.We have previously reported that sciatic nerve axons repaired by PEG-fusion do not undergo Wallerian degeneration,and PEG-fused animals exhibit rapid(within 2–6 weeks)and extensive locomotor recovery.Furthermore,our previous report showed that PEG-fusion of severed sciatic motor axons was non-specific,i.e.,spinal motoneurons in PEG-fused animals were found to project to appropriate as well as inappropriate target muscles.In this study,we examined the consequences of PEG-fusion for sensory axons of the sciatic nerve.Young adult male and female rats(Sprague–Dawley)received either a unilateral single cut or ablation injury to the sciatic nerve and subsequent repair with or without(Negative Control)the application of PEG.Compound action potentials recorded immediately after PEG-fusion repair confirmed conduction across the injury site.The success of PEG-fusion was confirmed through Sciatic Functional Index testing with PEG-fused animals showing improvement in locomotor function beginning at 35 days postoperatively.At 2–42 days postoperatively,we anterogradely labeled sensory afferents from the dorsal aspect of the hindpaw following bilateral intradermal injection of wheat germ agglutinin conjugated horseradish peroxidase.PEG-fusion repair reestablished axonal continuity.Compared to unoperated animals,labeled sensory afferents ipsilateral to the injury in PEG-fused animals were found in the appropriate area of the dorsal horn,as well as inappropriate mediolateral and rostrocaudal areas.Unexpectedly,despite having intact peripheral nerves,similar reorganizations of labeled sensory afferents were also observed contralateral to the injury and repair.This central reorganization may contribute to the improved behavioral recovery seen after PEG-fusion repair,supporting the use of this novel repair methodology over currently available treatments.展开更多
A series of novel polyethylene glycol-dicationic imidazolium-based ionic liquids(mPEG-ILs)were synthesized by facile quaternization reaction from various elaborately designed di-imidazoles and PEG,which were then stud...A series of novel polyethylene glycol-dicationic imidazolium-based ionic liquids(mPEG-ILs)were synthesized by facile quaternization reaction from various elaborately designed di-imidazoles and PEG,which were then studied as green plasticizers for sustainable polylactide(PLA)material.展开更多
Poly(butylene adipate-terephthalate)(PBAT),as one of the most common and promising biodegradable plastics,has been widely used in agriculture,packaging,and other industries due to its strong biodegradability propertie...Poly(butylene adipate-terephthalate)(PBAT),as one of the most common and promising biodegradable plastics,has been widely used in agriculture,packaging,and other industries due to its strong biodegradability properties.It is well known that PBAT suffers a series of natural weathering,mechanical wear,hydrolysis,photochemical transformation,and other abiotic degradation processes before being biodegraded.Therefore,it is particularly important to understand the role of abiotic degradation in the life cycle of PBAT.Since the abiotic degradation of PBAT has not been systematically summarized,this review aims to summarize the mechanisms and main factors of the three major abiotic degradation pathways(hydrolysis,photochemical transformation,and thermochemical degradation)of PBAT.It was found that all of them preferentially destroy the chemical bonds with higher energy(especially C-O and C=O)of PBAT,which eventually leads to the shortening of the polymer chain and then leads to reduction in molecular weight.The main factors affecting these abiotic degradations are closely related to the energy or PBAT structure.These findings provide important theoretical and practical guidance for identifying effective methods for PBAT waste management and proposing advanced schemes to regulate the degradation rate of PBAT.展开更多
Agricultural practices significantly contribute to greenhouse gas(GHG)emissions,necessitating cleaner production technologies to reduce environmental pressure and achieve sustainable maize production.Plastic film mulc...Agricultural practices significantly contribute to greenhouse gas(GHG)emissions,necessitating cleaner production technologies to reduce environmental pressure and achieve sustainable maize production.Plastic film mulching is commonly used in the Loess Plateau region.Incorporating slow-release fertilizers as a replacement for urea within this practice can reduce nitrogen losses and enhance crop productivity.Combining these techniques represents a novel agricultural approach in semi-arid areas.However,the impact of this integration on soil carbon storage(SOCS),carbon footprint(CF),and economic benefits has received limited research attention.Therefore,we conducted an eight-year study(2015-2022)in the semi-arid northwestern region to quantify the effects of four treatments[urea supplied without plastic film mulching(CK-U),slow-release fertilizer supplied without plastic film mulching(CK-S),urea supplied with plastic film mulching(PM-U),and slow-release fertilizer supplied with plastic film mulching(PM-S)]on soil fertility,economic and environmental benefits.The results revealed that nitrogen fertilizer was the primary contributor to total GHG emissions(≥71.97%).Compared to other treatments,PM-S increased average grain yield by 12.01%-37.89%,water use efficiency by 9.19%-23.33%,nitrogen accumulation by 27.07%-66.19%,and net return by 6.21%-29.57%.Furthermore,PM-S decreased CF by 12.87%-44.31%and CF per net return by 14.25%-41.16%.After eight years,PM-S increased SOCS(0-40 cm)by 2.46%,while PM-U decreased it by 7.09%.These findings highlight the positive effects of PM-S on surface soil fertility,economic gains,and environmental benefits in spring maize production on the Loess Plateau,underscoring its potential for widespread adoption and application.展开更多
To better understand the migration behavior of plastic fragments in the environment,development of rapid non-destructive methods for in-situ identification and characterization of plastic fragments is necessary.Howeve...To better understand the migration behavior of plastic fragments in the environment,development of rapid non-destructive methods for in-situ identification and characterization of plastic fragments is necessary.However,most of the studies had focused only on colored plastic fragments,ignoring colorless plastic fragments and the effects of different environmental media(backgrounds),thus underestimating their abundance.To address this issue,the present study used near-infrared spectroscopy to compare the identification of colored and colorless plastic fragments based on partial least squares-discriminant analysis(PLS-DA),extreme gradient boost,support vector machine and random forest classifier.The effects of polymer color,type,thickness,and background on the plastic fragments classification were evaluated.PLS-DA presented the best and most stable outcome,with higher robustness and lower misclassification rate.All models frequently misinterpreted colorless plastic fragments and its background when the fragment thickness was less than 0.1mm.A two-stage modeling method,which first distinguishes the plastic types and then identifies colorless plastic fragments that had been misclassified as background,was proposed.The method presented an accuracy higher than 99%in different backgrounds.In summary,this study developed a novel method for rapid and synchronous identification of colored and colorless plastic fragments under complex environmental backgrounds.展开更多
Dislocations and disclinations are fundamental topological defects within crystals,which determine the mechanical properties of metals and alloys.Despite their important roles in multiple physical mechanisms,e.g.,dyna...Dislocations and disclinations are fundamental topological defects within crystals,which determine the mechanical properties of metals and alloys.Despite their important roles in multiple physical mechanisms,e.g.,dynamic recovery and grain boundary mediated plasticity,the intrinsic coupling and correlation between disclinations and dislocations,and their impacts on the deformation behavior of metallic materials still remain obscure,partially due to the lack of a theoretical tool to capture the rotational nature of disclinations.By using a Lie-algebra-based theoretical framework,we obtain a general equation to quantify the intrinsic coupling of disclinations and dislocations.Through quasi in-situ electron backscatter diffraction characterizations and disclination/dislocation density analyses in Mg alloys,the generation,coevolution and reactions of disclinations and dislocations during dynamic recovery and superplastic deformation have been quantitatively analyzed.It has been demonstrated that the obtained governing equation can capture multiple physical processes associated with mechanical deformation of metals,e.g.,grain rotation and grain boundary migration,at both room temperature and high temperature.By establishing the disclination-dislocation coupling equation within a Lie algebra description,our work provides new insights for exploring the coevolution and reaction of disclinations/dislocations,with profound implications for elucidating the microstructure-property relationship and underlying deformation mechanisms in metallic materials.展开更多
Brain plasticity-A universal tool with many variations:The study of brain plasticity has been gaining interest since almost a century and has now reached a huge amount of information(>80,000 results in PubMed).Over...Brain plasticity-A universal tool with many variations:The study of brain plasticity has been gaining interest since almost a century and has now reached a huge amount of information(>80,000 results in PubMed).Overall,different types of plasticity,including stem cell-driven genesis of new neurons(adult neurogenesis),cells in arrested maturation(dormant neurons),neuro-glial and synaptic plasticity,can coexist and contribute to grant plastic changes in the brain,from a cellular to system level(Benedetti and Couillard-Despres,2022;Bonfanti et al.,2023).展开更多
文摘The deficiencies of popular phthalate plasticizers(ready migration from a polymer matrix into which they have been incorporated,flammability,environmental pollution,human health risks)have stimulated efforts to develop new effective,nonmigrating,low-cost,nontoxic replacements.In the main,these have been based on readilyavailable,nontoxic biobased precursors.Some,including those prepared from plant oils,have been generated from biomaterials themselves.However,the more numerous and generally more effective have been generated from discrete compounds produced from various biomaterials.Several structural features of effective plasticizers have been recognized.Polar functionality is required to assure compatibility with a wide range of polymeric materials,including poly(vinyl chloride)(PVC),the most heavily plasticized polymer.A branched structure greatly enhances the effectiveness of compounds used as plasticizers.An oligomeric structure may strongly limit or prevent migration from a polymer matrix.Hyperbranched oligomers of defined structure derived from the readilyavailable,inexpensive,nontoxic biomonomers,glycerol and adipic acid contain all these features and are excellent plasticizers.They contain ester functionality,are highly branched,and display a large number of end groups,all of which contribute to their effectiveness as plasticizers.
文摘Cellulose acetate(CA)is an important cellulose derivative that can undergo thermoplas-tic processing.Plasticizers can form stable hydrogen bonds with CA molecular chains,reducing intermolecular and intramolecular interactions,and play an important role in the melting processing of CA.In recent years,environmentally friendly plasticizers that are natural,non-toxic,odorless,low dissolution,and low migration have received increas-ing attention in plastic processing.This article reviews the research progress of environ-mentally friendly plasticizers such as natural plasticizers,ionic liquid plasticizers,citrate plasticizers,and polyethylene glycol plasticizers in the processing of cellulose acetate,and looks forward to the application prospects of environmentally friendly plasticizers.
文摘The effects of plasticizers,antioxidants and burning rate modifiers on the aging performance of the composite solid propellant based on hydroxyl-terminated polybutadiene(HTPB)/hexamethylene diisocyanate(HMDI)were explored by apply-ing an accelerated aging program for 90 day at 70 ℃. The HTPB propellant matrix with the diisooctyl sebacate(DOS)as plasti-cizers and diisooctyl azelate(DOZ), antioxidants as N,N ′-Diphenyl-p-phenylenediamine(AO) and 2,2′-methylenebis(4-methyl-6-tert-butylphenol)(cyanox 2246)and burning rate modifiers as barium ferrite(BF),copper chromites(CC)and fer-ric oxide(FO)were varied. Results show that sample(S1)which based on DOS decreases the stress value and increases the strain value which considered to be an excellent start for aging program. Sample(S3)containing AO presents the higher resis-tance to oxidation showing the better performance that reflects on increasing the shelf life of the composite solid propellant mo-tor. Sample(S5)which based on BF enhances the ballistic performance among over the other tested two samples. The accelerat-ed aging program allowed us to estimate the motor in-service lifetime.
文摘This aim of this work is to study the partial replacement of the plasticizer ordinarily used di-octyl phtalate (DOP) by the permanent plasticizers ethylene-vinyl-acetate (EVA) and acrylonytrile-bu- tadiene-styrene (ABS) in order to reduce migration of additives initially contents in polyvinyl chloride (PVC) stabilized with expoxidized sunflower oil (ESO). Migration tests with agitation to 40°C in sunflower oil and ethanol at 15% were made. Migration phenomenon was studied on the basis of the PVC samples mass variations, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) analysis. The results showed the effectiveness of the approach consisting in the partial substitution of DOP by plasticizers of polymeric nature. The following order concerning the migration of additives was found: DOP (40) > DOP:EVA > (30/10) DOP:ABS (30/10). Furthermore, all the measured values of overall migrations were lower than the maximum allowable overall migration: 10 mg-dm-2.
基金Funded by the Major State Basic Research Development Program of China (973 Program) (No. 2009CB623104)the National Technology R&D Program for the 11th Five-year Plan (No. 2006BAJ05B03)
文摘The inhibition and its mechanism of sodium tripolyphosphate （STP） composited with super plasticizers （SPs） on hydration of α-calcium sulfate hemihydrate were studied by setting time, strength, hydration heat, X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, electronic probe micro analysis （EPMA）, scanning electron microscopy （SEM） and differential scanning calorimeter （DSC） measurements. The experimental results show that compared with STP addition, compositing STP with polycarboxylate （PC） plasticizer, the final setting time is prolonged from 0.5h to 2hs. While formulating STP with naphthalene-based plasticizer （NAP） or sulfonate melamine formaldehyde plasticizer （SMF）, the final setting time is reduced to quarter of an hour. Similar changes can also be found in the rate of exothermic hydration and hydration degree. Formulating STP with suitable addition of PC can enhance the strength, while compositing STP and NAP or SMF weakens the strength. Besides, adding STP or STP and SMF, obvious movement （more than 1ev） of binding energy of Ca2p1/2 and Ca2p3/2 is detected. Compared with STP addition, content of the characteristic element （P） of STP is cut down form 1.1% to 0.49% by compositing STP with SMF. Furthermore, as hydration age increases, hydration inhibition in the presence of admixtures weakens and even disappears within 56 h.
基金financial support of the National Natural Science Foundation of China (21875185)。
文摘Geminal dinitropropyl ester plasticizers(DNPEPs) possess excellent energetic performances which provide good potentials as insensitive plasticizer. In this study, we design and synthesize DNPEPs with different alkane chain parts, and systematically investigate their structure-property relationships.Results show that DNPEPs have impact sensitivities all higher than 25.2 J, thermal decomposition temperatures all higher than 254 ℃, and glass transition temperatures(T_(g)) lower than-90 ℃.Furthermore, the effects of DNPEPs as plasticizer are studied on hydroxyl terminated polybutadiene(HTPB) in detail, including the viscosity, glass transition temperatures and others. It is noteworthy that 2,2-dinitropropyl nonanoate(DNPNc) among these DNPEPs exhibits the most expected simultaneous tuning effects on both viscosity and T_(g) of HTPB systems, providing favorable potentials to replace the conventional plastizers as dioctyl sebacate(DOS) in the HTPB based propellants and explosives.
基金Funded by the Fundamental Research Funds for the Central Universities(DL13CB13)the China Postdoctoral Science Foundation Funded Project(No.2014M550178)the National Natural Science Foundation of China(No.31200442)
文摘Ethylene glycol, glycerol, sorbitol, formamide, and urea were used as plasticizers for the preparation of thermoplastic starch（TPS） from corn starch. The properties of TPS were tested by analysis method. The results showed that TPSs were more highly plasticized with amines than alcohols. For the same type of plasticizer, the degree of plasticization decreased as the molecular weight of plasticizer increased. The relationship between plasticization degree and TPS properties was characterized and described by mechanical properties and water absorption. The experimental results showed that when the degree of plasticization increased, the tensile strength decreased and the elongation at breakage and water absorption increased.
基金Supported by the Fund of Science and Technology Research Project of the 12th Five-year Plan(2012BAD32B02-5)
文摘In order to improve the properties of rice straw fiber film, one factor contrast test method was employed. Plasticizer type was chosen as input variable, dry tension strength and elongation, wet tension strength and elongation, bursting strength and tearing strength were chosen as indexes. The results showed that there were significant differences among the means of dry tension strength, dry elongation and bursting strength of different plasticizers; there were not significant differences among the means of wet tension strength, wet elongation and tearing strength of different plasticizers; for dry tension strength and elongation, glycerol had a significant difference with sorbitol and PEG, no significant difference was observed between sorbitol and PEG, dry tension strength added glycerol had been reduced 6.8% compared with that added sorbitol, reduced 9.5% compared with that added PEG; elongation had been improved 6.1% and 9.4%, respectively; for bursting strength, sorbitol had a significant difference with glycerol and PEG, no significant difference was observed between glycerol and PEG; bursting strength added glycerol and added PEG had been improved 6.9% and 5.6%, respectively compared with that of the added sorbitol. The results provided a theoretical reference for further improving the straw fiber film manufacturing process.
文摘The effects of glycerol and sorbitol as two plasticizers on mechanical properties, water vapor permeability, thermal properties, color and capability of heat sealing of gelatin films (of phytophagous fish, bovine gelatin with high gel-forming ability, and bovine gelatin with low gel-forming ability) containing clay nanoparticles were studied in this research. For this purpose, 6 × 2 × 3 factorial experiments using the completely randomized design and comparison of the means at 95% confidence level (α = 0.05) were performed. Higher concentrations of plasticizers increased percentage elongation to the breaking point. When glycerol concentration was raised to over 20%, flexibility of the layers improved but their water vapor permeability increased. The minimum passage of water vapor was that of fish-skin gelatin films containing clay nanoparticles and 30% sorbitol, and the maximum that of bovine gelatin films with high gel-forming ability which contained nanoparticles but no plasticizers (p 0.05). All samples had heat sealing capability, and fish-skin gelatin films containing clay nanoparticles had better heat sealing capability compared with the other samples so that fish-skin gelatin films containing clay nanoparticles with 25% glycerol and 5% sorbitol had the highest flexibility and tensile strength, and remained attached to where they were heat sealed. Electron microscope images showed that films without plasticizers had uniform surfaces, but that samples containing glycerol at concentrations of over 0.20 g/g gelatin exhibited cavities between gelatin chains and that water vapor permeability in gelatin films containing clay nanoparticles.
基金supported by grants from the the Science and Technology Planning Project of Guangzhou(202102080163)Dean's Research Fund of the Faculty of Liberal Arts and Social Sciences,The Education University of Hong Kong,Hong Kong SAR,China(FLASS/DRF/IRF-I).
文摘Numerous studies reported risk assessment of human exposure to plasticizers in toys through dermal pathways,however,dermal bioaccessibility and percutaneous penetration of plasticizers under effects of lead had been seldom studied.In the present study,dermal bioaccessibility of plasticizers including phthalate esters and alternative plasticizers in toys were examined in artificial sweat and SSSM(synthetic sweat and sebum mixture),and percutaneous penetration of plasticizers were investigated by skin cells under individual plasticizers exposure or combined exposure conditions(plasticizers t lead).The present results indicated that dermal bioaccessibility of plasticizers in SSSM were higher than that in artificial sweat.DEHP(Di-2-ethylhexyl Phthalate)showed highest bioaccessibility among all the plasticizers,DEHT(Di(2-ethylhexyl)terephthalate)showed highest bioaccessibility among all the alternative plasticizers.DEHP and DEHT were selected to perform the cell absorption assay.Skin cell absorption assay demonstrated that MEHP(Mono-(2-ethylhexyl)phthalate)was the major metabolite of DEHP and the absorption percentage of DEHP was higher than that of DEHT.Compared to individual exposure of plasticizers,the absorption percentage of DEHP and DEHT in skin cells under the combined exposure condition were increased by 12.40%e14.63%and 8.35%e9.84%,respectively.Risk assessment indicated that the plasticizers in toy would not result in unacceptable risk for children,but the health risk of plasticizers in toys to children under combined exposure condition would be 1.5e2 times higher than that under individual exposure condition.
基金supported by the National Key Research&Development Programof China,Ministry of Science and Technology(Nos.2022YFE0134900 and 2022YFC3703200)the Key Research and Development Programof Zhejiang Province,China(No.2024C03228)the National Nature Science Foundation of China(Nos.22376184 and 22076166).
文摘There is growing concern about the concept that exposure to environmental chemicals may be contributing to the obesity epidemic.However,there is no consensus on the obesogenic effects of emerging contaminants from a toxicological and environmental perspective.The potential human exposure and experimental evidence for obesogenic effects of emerging contaminants need to be systematically discussed.The main objective of this review is to provide recommendations for further subsequent policy development following a critical analysis of the literature for humans and experimental animals exposed to emerging contaminants.This article reviews human exposure to emerging contaminants(with a focus on antimicrobials,preservatives,water and oil repellents,flame retardants,antibiotics and bisphenols)and the impact of emerging contaminants on obesity.These emerging contaminants have been widely detected in human biological samples.Epidemiological studies provide evidence linking exposure to emerging contaminants to the risks of obesity in humans.Studies based on animalmodels and adipose cells show the obesogenic effects of emerging contaminants and identify modes of action by which contaminants may induce changes in body fat accumulation and lipid metabolic homeostasis.Some knowledge gaps in this area and future directions for further investigation are discussed.
基金supported by the NIH (R01NS103481, R01NS111776, and R01NS131489)Indiana Department of Health (ISDH58180)(all to WW)。
文摘Spinal cord injury necessitates effective rehabilitation strategies, with exercise therapies showing promise in promoting recovery. This study investigated the impact of rehabilitation exercise on functional recovery and morphological changes following thoracic contusive spinal cord injury. After a 7-day recovery period after spinal cord injury, mice were assigned to either a trained group(10 weeks of voluntary running wheel or forced treadmill exercise) or an untrained group. Bi-weekly assessments revealed that the exercise-trained group, particularly the voluntary wheel exercise subgroup, displayed significantly improved locomotor recovery, more plasticity of dopaminergic and serotonin modulation compared with the untrained group. Additionally, exercise interventions led to gait pattern restoration and enhanced transcranial magnetic motor-evoked potentials. Despite consistent injury areas across groups, exercise training promoted terminal innervation of descending axons. In summary, voluntary wheel exercise shows promise for enhancing outcomes after thoracic contusive spinal cord injury, emphasizing the role of exercise modality in promoting recovery and morphological changes in spinal cord injuries. Our findings will influence future strategies for rehabilitation exercises, restoring functional movement after spinal cord injury.
基金supported by the Department of Defense AFIRMⅢW81XWH-20-2-0029 grant subcontractLone Star Paralysis gift,UT POC19-1774-13 grant+1 种基金Neuraptive Therapeutics Inc.26-7724-56 grantNational Institutes of Health R01-NS128086(all to GDB)。
文摘Peripheral nerve injuries result in the rapid degeneration of distal nerve segments and immediate loss of motor and sensory functions;behavioral recovery is typically poor.We used a plasmalemmal fusogen,polyethylene glycol(PEG),to immediately fuse closely apposed open ends of severed proximal and distal axons in rat sciatic nerves.We have previously reported that sciatic nerve axons repaired by PEG-fusion do not undergo Wallerian degeneration,and PEG-fused animals exhibit rapid(within 2–6 weeks)and extensive locomotor recovery.Furthermore,our previous report showed that PEG-fusion of severed sciatic motor axons was non-specific,i.e.,spinal motoneurons in PEG-fused animals were found to project to appropriate as well as inappropriate target muscles.In this study,we examined the consequences of PEG-fusion for sensory axons of the sciatic nerve.Young adult male and female rats(Sprague–Dawley)received either a unilateral single cut or ablation injury to the sciatic nerve and subsequent repair with or without(Negative Control)the application of PEG.Compound action potentials recorded immediately after PEG-fusion repair confirmed conduction across the injury site.The success of PEG-fusion was confirmed through Sciatic Functional Index testing with PEG-fused animals showing improvement in locomotor function beginning at 35 days postoperatively.At 2–42 days postoperatively,we anterogradely labeled sensory afferents from the dorsal aspect of the hindpaw following bilateral intradermal injection of wheat germ agglutinin conjugated horseradish peroxidase.PEG-fusion repair reestablished axonal continuity.Compared to unoperated animals,labeled sensory afferents ipsilateral to the injury in PEG-fused animals were found in the appropriate area of the dorsal horn,as well as inappropriate mediolateral and rostrocaudal areas.Unexpectedly,despite having intact peripheral nerves,similar reorganizations of labeled sensory afferents were also observed contralateral to the injury and repair.This central reorganization may contribute to the improved behavioral recovery seen after PEG-fusion repair,supporting the use of this novel repair methodology over currently available treatments.
基金The authors are grateful for financial support from the National Natural Science Foundation of China(No.51573130)the Open Foundation of Beijing Key Laboratory of Quality Evaluation Tech no logy for Hygiene and Safety of Plastics.
文摘A series of novel polyethylene glycol-dicationic imidazolium-based ionic liquids(mPEG-ILs)were synthesized by facile quaternization reaction from various elaborately designed di-imidazoles and PEG,which were then studied as green plasticizers for sustainable polylactide(PLA)material.
基金supported by the National Key R&D Program of China(No.2022YFC3901800)the National Natural Science Foundation of China(No.22176041)Guangzhou Science and Technology Planning Project(No.2023A04J0918)。
文摘Poly(butylene adipate-terephthalate)(PBAT),as one of the most common and promising biodegradable plastics,has been widely used in agriculture,packaging,and other industries due to its strong biodegradability properties.It is well known that PBAT suffers a series of natural weathering,mechanical wear,hydrolysis,photochemical transformation,and other abiotic degradation processes before being biodegraded.Therefore,it is particularly important to understand the role of abiotic degradation in the life cycle of PBAT.Since the abiotic degradation of PBAT has not been systematically summarized,this review aims to summarize the mechanisms and main factors of the three major abiotic degradation pathways(hydrolysis,photochemical transformation,and thermochemical degradation)of PBAT.It was found that all of them preferentially destroy the chemical bonds with higher energy(especially C-O and C=O)of PBAT,which eventually leads to the shortening of the polymer chain and then leads to reduction in molecular weight.The main factors affecting these abiotic degradations are closely related to the energy or PBAT structure.These findings provide important theoretical and practical guidance for identifying effective methods for PBAT waste management and proposing advanced schemes to regulate the degradation rate of PBAT.
基金supported by the National Natural Science Foundation of China(No.32071980)the Key Projects of Shaanxi Agricultural Collaborative Innovation and Extension Alliance(No.LMZD202201)+1 种基金the Key R&D Project in Shaanxi Province(No.2021LLRH-07)Shaanxi Natural Scientific Basic Research Program project(No.2022JQ-157).
文摘Agricultural practices significantly contribute to greenhouse gas(GHG)emissions,necessitating cleaner production technologies to reduce environmental pressure and achieve sustainable maize production.Plastic film mulching is commonly used in the Loess Plateau region.Incorporating slow-release fertilizers as a replacement for urea within this practice can reduce nitrogen losses and enhance crop productivity.Combining these techniques represents a novel agricultural approach in semi-arid areas.However,the impact of this integration on soil carbon storage(SOCS),carbon footprint(CF),and economic benefits has received limited research attention.Therefore,we conducted an eight-year study(2015-2022)in the semi-arid northwestern region to quantify the effects of four treatments[urea supplied without plastic film mulching(CK-U),slow-release fertilizer supplied without plastic film mulching(CK-S),urea supplied with plastic film mulching(PM-U),and slow-release fertilizer supplied with plastic film mulching(PM-S)]on soil fertility,economic and environmental benefits.The results revealed that nitrogen fertilizer was the primary contributor to total GHG emissions(≥71.97%).Compared to other treatments,PM-S increased average grain yield by 12.01%-37.89%,water use efficiency by 9.19%-23.33%,nitrogen accumulation by 27.07%-66.19%,and net return by 6.21%-29.57%.Furthermore,PM-S decreased CF by 12.87%-44.31%and CF per net return by 14.25%-41.16%.After eight years,PM-S increased SOCS(0-40 cm)by 2.46%,while PM-U decreased it by 7.09%.These findings highlight the positive effects of PM-S on surface soil fertility,economic gains,and environmental benefits in spring maize production on the Loess Plateau,underscoring its potential for widespread adoption and application.
基金supported by the National Natural Science Foundation of China(No.22276139)the Shanghai’s Municipal State-owned Assets Supervision and Administration Commission(No.2022028).
文摘To better understand the migration behavior of plastic fragments in the environment,development of rapid non-destructive methods for in-situ identification and characterization of plastic fragments is necessary.However,most of the studies had focused only on colored plastic fragments,ignoring colorless plastic fragments and the effects of different environmental media(backgrounds),thus underestimating their abundance.To address this issue,the present study used near-infrared spectroscopy to compare the identification of colored and colorless plastic fragments based on partial least squares-discriminant analysis(PLS-DA),extreme gradient boost,support vector machine and random forest classifier.The effects of polymer color,type,thickness,and background on the plastic fragments classification were evaluated.PLS-DA presented the best and most stable outcome,with higher robustness and lower misclassification rate.All models frequently misinterpreted colorless plastic fragments and its background when the fragment thickness was less than 0.1mm.A two-stage modeling method,which first distinguishes the plastic types and then identifies colorless plastic fragments that had been misclassified as background,was proposed.The method presented an accuracy higher than 99%in different backgrounds.In summary,this study developed a novel method for rapid and synchronous identification of colored and colorless plastic fragments under complex environmental backgrounds.
基金Financial supports from the National Natural Science Foundation of China(Nos.52171116,U22A20109,52334010 and T2325013)are greatly acknowledgedPartial financial support came from The Program for the Central University Youth Innovation Team,and the Fundamental Research Funds for the Central Universities,JLU.
文摘Dislocations and disclinations are fundamental topological defects within crystals,which determine the mechanical properties of metals and alloys.Despite their important roles in multiple physical mechanisms,e.g.,dynamic recovery and grain boundary mediated plasticity,the intrinsic coupling and correlation between disclinations and dislocations,and their impacts on the deformation behavior of metallic materials still remain obscure,partially due to the lack of a theoretical tool to capture the rotational nature of disclinations.By using a Lie-algebra-based theoretical framework,we obtain a general equation to quantify the intrinsic coupling of disclinations and dislocations.Through quasi in-situ electron backscatter diffraction characterizations and disclination/dislocation density analyses in Mg alloys,the generation,coevolution and reactions of disclinations and dislocations during dynamic recovery and superplastic deformation have been quantitatively analyzed.It has been demonstrated that the obtained governing equation can capture multiple physical processes associated with mechanical deformation of metals,e.g.,grain rotation and grain boundary migration,at both room temperature and high temperature.By establishing the disclination-dislocation coupling equation within a Lie algebra description,our work provides new insights for exploring the coevolution and reaction of disclinations/dislocations,with profound implications for elucidating the microstructure-property relationship and underlying deformation mechanisms in metallic materials.
基金supported by Progetto Trapezio,Compagnia di San Paolo(67935-2021.2174)to LB,Fondazione CRT(Cassa di Risparmio di Torino,RF=2022.0618)to LB。
文摘Brain plasticity-A universal tool with many variations:The study of brain plasticity has been gaining interest since almost a century and has now reached a huge amount of information(>80,000 results in PubMed).Overall,different types of plasticity,including stem cell-driven genesis of new neurons(adult neurogenesis),cells in arrested maturation(dormant neurons),neuro-glial and synaptic plasticity,can coexist and contribute to grant plastic changes in the brain,from a cellular to system level(Benedetti and Couillard-Despres,2022;Bonfanti et al.,2023).
