Zinc phenylphosphonate （PPZn）, a benign and biocompatible nucleating agent, was prepared and incorporated into the biodegradable poly（ethylene adipate） （PEA） to investigate its effect on the crystallization beha...Zinc phenylphosphonate （PPZn）, a benign and biocompatible nucleating agent, was prepared and incorporated into the biodegradable poly（ethylene adipate） （PEA） to investigate its effect on the crystallization behavior, crystallization kinetics and spherulite morphology of PEA. Upon addition of PPZn, the crystallization temperature and crystallinity of PEA in the non-isothermal crystallization process increased significantly. Analysis of crystallization kinetics by Avrami equation suggests that the crystallization time shortened greatly and crystallization rate increased markedly after addition of PPZn. In the presence of PPZn, the spherulite size decreased and spherulite density increased significantly. It suggests that PPZn is an efficient nucleating agent for the crystallization of PEA. The accelerated crystallization in the presence of PPZn is mainly attributed to the epitaxial nucleation of PEA crystals on the surface of PPZn crystals, that is, a perfect lattice matching between PEA crystal and PPZn crystal occurs.展开更多
The crystallization behavior and transparent property of MgO-A1203-SiO2 （MAS） glasses with TiO2 and TiO2＋ZrO2 as nucleating agents were discussed by differential thermal analysis, X-ray diffraction, field emission-...The crystallization behavior and transparent property of MgO-A1203-SiO2 （MAS） glasses with TiO2 and TiO2＋ZrO2 as nucleating agents were discussed by differential thermal analysis, X-ray diffraction, field emission-environment scanning electron microscope, energy dispersive spectrum and UV-VIS-NIR scanning spectrophotometer. It was found that the glass crystallized at 950 ℃ with ZrO2 less than 3% could obtain transparent glass ceramic, which presented purple to colorless. With the nucleating agent additives （5% TIO2＋3% ZrO2）, the colorless transparent glass-ceramics with spinel as the main crystal phase could be prepared, and the transmittance reached about 80%. As the crystallized temperature increase to 1 000 ℃, besides spinel（MgA1204）, sapphirine （Mg3.5A19Si1.5O20） and ZrTiO4 precipitated from matrix glass, and the transmitance of glass-ceramic decreased.展开更多
The effect of a novel active nucleating agent(TBC8-eb) on the isothermal crystallization of poly(L-lactic acid) (PLLA) was studied by differential scanning calorimetry(DSC) and Fourier transform infrared spectroscopy(...The effect of a novel active nucleating agent(TBC8-eb) on the isothermal crystallization of poly(L-lactic acid) (PLLA) was studied by differential scanning calorimetry(DSC) and Fourier transform infrared spectroscopy(FTIR) . The analysis on kinetics demonstrates that TBC8-eb can not only accelerate the crystallization rate but also transform most of the original spherulite crystals of PLLA into sheaf-like crystals. Furthermore,the free energy of folding(σe) of PLLA and PLLA with TBC8-eb is 0.15 and 0.06 J·m-2,respectively,which suggests that the addition of TBC8-eb favors the regular folding of molecule chains in the crystallization of PLLA,improv-ing its crystallization rate. The FTIR results show that TBC8-eb can accelerate the conformational ordering of PLLA in the isothermal crystallization. The conformational ordering of PLLA nucleated with TBC8-eb begins with the interchain interaction of CH3,and then a short helix emerges where a couple of CH3 groups interact.展开更多
It is deduced from thermodynamic relations and confirmed by experiment results that the nucleation rate and nucleation temperature of nucleating agents in the glass are dependent upon their melting entropy Delta S//m ...It is deduced from thermodynamic relations and confirmed by experiment results that the nucleation rate and nucleation temperature of nucleating agents in the glass are dependent upon their melting entropy Delta S//m melting temperature T//m and crystal - type transition in terms of some mathematical expressions. (Author abstract) 10 Refs.展开更多
An aryl dicarboxylic acid amide compound TMB-5 is an efficient β-form nucleating agent for isotactic polypropylene （iPP）. Because of the solubility of TMB-5, superstructure and morphology of iPP crystals changed wi...An aryl dicarboxylic acid amide compound TMB-5 is an efficient β-form nucleating agent for isotactic polypropylene （iPP）. Because of the solubility of TMB-5, superstructure and morphology of iPP crystals changed with melting conditions. Effects of final heating temperature （Tf） on heterogeneous nucleation of iPP/TMB-5 were investigated. It was discovered that the crystallization temperature increased with decreasing Tf value. The optical microscopic images indicated that when TMB-5 partially dissolved in iPP melt, the remaining （non-dissolved） TMB-5 facilitated the recrystallization of dissolved nucleating agent from the melt, which promoted crystallization. Complete solubility of nucleating agent caused the decreasing efficiency. TMB-5 recrystallized in the form of tiny needles, whose aggregates induced dendritic iPP crystals.展开更多
Although addition of β-nucleating agent directly into homo-polypropylene （PPH） is a useful method to improve ,β-crystal content and toughen PPH, polypropylene random copolymer （PPR） makes this method powerless d...Although addition of β-nucleating agent directly into homo-polypropylene （PPH） is a useful method to improve ,β-crystal content and toughen PPH, polypropylene random copolymer （PPR） makes this method powerless due to its random structure and low crystallinity. In this study, the β-nucleated PPR with high β-crystal content was prepared by a novel high effective β-nucleating system which consists of β-nucleation agent （TMB-5） and modified zeolite 13X （M13X）. It was found that M13X and TMB-5 had a synergistic influence on improving β-crystal content and toughening PPR. The content of β-crystal in PPR/M13X/TMB-5 was significantly larger than the sum of that in PPR/M13X and PPR/TMB-5. Besides, fracture behavior, phase morphology and relaxation of matrix chain segments were also investigated. The results showed that M13X and TMB-5 improved the mobility of amorphous chain segments at low temperature and contributed to much energy dissipation. This work provides a powerful method to modify PPR.展开更多
The melting behavior of polypropylene (PP) and low ethylene content polypropylenecopolymer with and without nucleating agent samples crystallized under both isothermal and non-isothermal conditions were studied by Dif...The melting behavior of polypropylene (PP) and low ethylene content polypropylenecopolymer with and without nucleating agent samples crystallized under both isothermal and non-isothermal conditions were studied by Differential Scanning Calorimeter (DSC) and X-raydiffraction. Multiple melting behavior were observed depending on the existence of nucleatingagent and crystallization conditions. The observed phenomena have been discussed by the effect ofnucleating agent on perfection of crystal and the melting and recrystallization of imperfect crystalto a more perfect crystal during the heating process of samples.展开更多
Poly(butylene adipate-co-terephthalate)(PBAT)is a promising biodegradable flexible polymer but suffers from slow crystallization rate,making it less attractive for some applications like the injection-molded products ...Poly(butylene adipate-co-terephthalate)(PBAT)is a promising biodegradable flexible polymer but suffers from slow crystallization rate,making it less attractive for some applications like the injection-molded products in comparison with low-density polyethylene(LDPE).This work aimed to accelerate the crystallization of PBAT by adding a self-assembly nucleating agent octamethylenedicarboxylic dibenzoylhydrazide(OMBH).PBAT/OMBH composites with various OMBH contents(0 wt%,0.5 wt%,0.7 wt%,1 wt%,2 wt%,3 wt%and 5 wt%)were prepared through melt-mixing.The effect of OMBH on the crystallization behavior,morphologies and mechanical properties of PBAT was investigated.The highest nucleation efficiency value of 59.6%was achieved for PBAT with 0.7 wt%OMBH,much higher than that of 22.7%for PBAT with 0.7 wt%talc.Atomic force microscopy results showed that OMBH formed fine fibers and induced the formation of transcrystalline layers of PBAT.Fourier transform infrared spectroscopy(FTIR)combined with two-dimensional correlation spectra suggested that the intermolecular dipole-dipole N—H…O=C interactions but not hydrogen bond between OMBH and PBAT promoted the crystallization of PBAT in the initial period of crystallization.The presence of OMBH did not change the crystal form of PBAT but had positive contribution in enhancing its crystallinity and mechanical properties.This work is essential for preparing PBAT with high crystallization rate,enhancing its potential applications in injection-molded products.展开更多
The crystalline structures and crystallization behaviors of iPP containing β nucleation agent TMB-5 （iPP/TMB-5） were investigated by synchrotron radiation wide angel X-ray diffraction （SR-WAXD）, differential scan...The crystalline structures and crystallization behaviors of iPP containing β nucleation agent TMB-5 （iPP/TMB-5） were investigated by synchrotron radiation wide angel X-ray diffraction （SR-WAXD）, differential scanning calorimeter （DSC） and polarized light microscope （PLM）. It was found that α-crystallization lagged behind β-crystallization at normal temperatures, but the discrepancy reduced with increasing temperature. TMB-5 could not induce β-iPP when the nucleation agent is wrapped up with α-crystal that crystallized at high temperatures. The polymorphic composition of iPP/TMB-5 was susceptible to the introductory moment of shear. New crystallization process of β-nucleated iPP was proposed to understand the experimental phenomena which could not be explained by those reported in the literature. It was supposed that polymer crystallization initiated from mesophase, and the formations of iPP crystals involved the organization of helical conformation ordering within rnesophase. It was proposed that the iPP melt contained mesophases with stereocomplex-type ordering of right-handed and left-handed helical chains which could be disturbed by shear or TMB-5, leading to different polymorphic structures.展开更多
Impregnation of isotactic polypropylene (iPP) with nucleating agent (NA21) using supercritical carbon dioxide as the swelling agent at different temperature and pressure and its non-isothermal crystallization kinetics...Impregnation of isotactic polypropylene (iPP) with nucleating agent (NA21) using supercritical carbon dioxide as the swelling agent at different temperature and pressure and its non-isothermal crystallization kinetics were investigated. The results showed that NA21 was dispersed at a nanometer-scale in the PP matrix, resulting in the formation of different typesof crystal phases of iPP and the enhancement of its mechanical properties.展开更多
The influence of aryl amide compounds（TMB）as b-nucleating agents, on the non-isothermal crystallization of a wood-flour/polypropylene composite（WF/PP）prepared by compression molding was investigated by wide-angle ...The influence of aryl amide compounds（TMB）as b-nucleating agents, on the non-isothermal crystallization of a wood-flour/polypropylene composite（WF/PP）prepared by compression molding was investigated by wide-angle X-ray diffraction and differential scanning calorimetry. TMB was proved to be an effective b-crystalline nucleating agent for WF/PP. The DSC data showed that the crystallization peak temperature（Tp） increased and the half-time（t1/2） decreased with the addition of TMB.Three theoretical models were used to analyze the nonisothermal crystallization process. The modified Avrami method and Mo method successfully explained the nonisothermal crystallization behavior of PP and its composites. Their activation energies for non-isothermal crystallization were determined basing on the Kissinger method.展开更多
A novel polypropylene random(PPR)composite materials with optimized properties was developed by addingβ-nucleating compound agents(rare earth complex WBG-2 and aryl amide derivative TMB-5)and ternary compound modifie...A novel polypropylene random(PPR)composite materials with optimized properties was developed by addingβ-nucleating compound agents(rare earth complex WBG-2 and aryl amide derivative TMB-5)and ternary compound modifier(TPE/WBG-2/CaCO_(3)).The effects of differentβ-nucleating agents and ternary compound modifier on the mechanical properties and crystallization behavior of PPR were analyzed.The results show that,compared with pure PPR materials,both WBG-2 and TMB-5 could significantly improve the impact strength of PPR.The crystallization temperature of PPR increased with the addition ofβ-nucleating agent.The modified PPR prepared with ternary compound modifier showed the most excellent comprehensive properties.展开更多
Herein,isotactic polypropylene films with smallβ-nucleating agent content were fabricated via a melt-extrusion-stretched technology with intended"shear-free"in barrel and die.Compared with neat films,the te...Herein,isotactic polypropylene films with smallβ-nucleating agent content were fabricated via a melt-extrusion-stretched technology with intended"shear-free"in barrel and die.Compared with neat films,the tensile strength,elongation at break and strain energy density at break of i PP film with 0.05 wt%β-nucleating agent are significantly improved by 13.8%,39.6%and 90.6%,respectively,indicating the simultaneously enhanced toughness and strength.Additionally,theβ-crystal content gradually increases with increasingβ-NA content,while the relative total daughter content ofα-andβ-crystal exhibits opposite tendency.Moreover,nucleation and crystal growth induced by variousβ-NA contents are different.This work proves an efficient strategy to enhance mechanical properties of isotactic polypropylene film via controlling elongation flow and addition of appropriateβ-NA content.展开更多
Glass ceramics was made by the one-time sintering method using the main raw material of iron tailings. On the basis of quaternary system of CaO-MgO-Al2O3-SiO2, using DTA, XRD and SEM, the effects of different nucleati...Glass ceramics was made by the one-time sintering method using the main raw material of iron tailings. On the basis of quaternary system of CaO-MgO-Al2O3-SiO2, using DTA, XRD and SEM, the effects of different nucleating agents and mixing amounts as well as heat treatment on the crystallization of railings glass ceramics were studied. The experimental results show that, nucleating agent and heat treatment are two necessary conditions for one-time sintering preparation of tailings glass ceramics namely, only adding nucleating agent or experiencing heat treatment, the quaternary system can not crystallize. The composite nucleating agent consisting of Cr2O3 and TiO2 can further lead to the crystallization of the CaO-MgO-A1203-SiO2 quaternary system at the lower temperature, with the major phase of diopside. In the range of mass content, 0%-4%, crystal intensity and crystal content grow. But when mass content is more than 4%, the crystal size will become coarser and the crystal distribution will be less regular. Different heat treatment regimes do not change the composition of the crystalline major phase in the glass ceramics crystallization of CaO-MgO-Al2O3-SiO2 system. In the range of 30-60 minutes, with the extension of nucleation and crystallization, crystallization degree enhanced, but if the holding time surpasses 60 minutes, the crystallization is worse.展开更多
The influence of cyanuric acid（CA） as an efficient nucleating agent on the crystallization behavior and morphology of biodegradable poly（ε-caprolactone）（PCL） was extensively studied in this work with several te...The influence of cyanuric acid（CA） as an efficient nucleating agent on the crystallization behavior and morphology of biodegradable poly（ε-caprolactone）（PCL） was extensively studied in this work with several techniques for the first time. The nonisothermal melt crystallization behavior and overall isothermal melt crystallization rate of PCL were significantly enhanced by only a small amount of CA. The addition of CA apparently improved the nonisothermal melt crystallization peak temperature, overall isothermal melt crystallization rate, and nucleation density of PCL spherulites, but did not modify the crystallization mechanism and crystal structure of PCL, indicating that CA was an efficient nucleating agent for the crystallization of PCL. The possible nucleation mechanism of CA on the crystallization of PCL was also discussed on the basis of their crystal structures.展开更多
The reference test methods are carried out parallelly, by means of chemical analysis, X-ray diffraction, differential scanning calorimetry-thermogravimetry, scanning electron microscopy and polarized optical microscop...The reference test methods are carried out parallelly, by means of chemical analysis, X-ray diffraction, differential scanning calorimetry-thermogravimetry, scanning electron microscopy and polarized optical microscope to study the formation of C4A3S in the presence and absence of nucleating agent. The results show that nucleating agent with high calcium and low heat consumption as tricalcium silicate （C3S） promotes the formation of C4A3S and increases desulfurization degree obviously. During calcining raw meals doped with C3S, the grain sizes of C4A3S are larger compared with that without C3S. And at the same calcining level, the mass loss and the heat consumption belonged to CaCO3 decomposition is reduced.展开更多
Poly(lactide acid)(PLA)foams have shown considerable promise as eco-friendly alternatives to nondegradable plastic foams,such as polystyrene(PS)foams.Nevertheless,PLA foam typically suffers from low heat-resistance an...Poly(lactide acid)(PLA)foams have shown considerable promise as eco-friendly alternatives to nondegradable plastic foams,such as polystyrene(PS)foams.Nevertheless,PLA foam typically suffers from low heat-resistance and poor cellular structure stemming from its inherent slow crystallization rate and low melt strength.In this study,a high-performance PLA foam with well-defined cell morphology,exceptional strength and enhanced heat-resistance was successfully fabricated via a core-back microcellular injection molding(MIM)process.Differential scanning calorimetry(DSC)results revealed that the added hydrazine-based nucleating agent(HNA)significantly increased the crystallization temperature and accelerated the crystallization process of PLA.Remarkably,the addition of a 1.5 wt%of HNA led to a significant reduction in PLA’s cell size,from 43.5µm to 2.87µm,and a remarkable increase in cell density,from 1.08×10^(7)cells/cm^(3)to 2.15×10^(10)cells/cm^(3).This enhancement resulted in a final crystallinity of approximately 55.7%for the PLA blend foam,a marked improvement compared to the pure PLA foam.Furthermore,at 1.5 wt%HNA concentration,the tensile strength and tensile toughness of PLA blend foams demonstrated remarkable improvements of 136%and 463%,respectively.Additionally,the Vicat softening temperature of PLA blend foam increased significantly to 134.8°C,whereas the pure PLA foam exhibited only about 59.7℃.These findings underscore the potential for the preparation of lightweight injection-molded PLA foam with enhanced toughness and heat-resistance,which offers a viable approach for the production of high-performance PLA foams suitable for large-scale applications.展开更多
Glass-ceramics obtained from the electric arc furnace molten slag of incinerator fly ash was produced by applying nucleation and crystallization through heat treatment process. The effects of nucleating agent （TiO2 a...Glass-ceramics obtained from the electric arc furnace molten slag of incinerator fly ash was produced by applying nucleation and crystallization through heat treatment process. The effects of nucleating agent （TiO2 and Cr2O3） on the crystallization kinetics and heat treatment schedule of the slag were investigated. The results show that the nucleating agents changed the crystallization phase and morphology of the obtained glass-ceramics. The optimum heat treatment schedule of the glass with TiO2 was determined as nucleation at 952 K for 1.5 h and crystal growth at 1 258 K for 1.5 h, while those values with Cr203 were estimated at 971 K for 2 h and at 1 238 K for 2 h. TiO2 acting as nucleating agent could decrease the activation energy of the slag and shorten the total thermal treatment time in comparison with Cr2O3. The glass-ceramics obtained under the optimum heat treatment condition was environmentfriendly and had remarkable physical/mechanical properties and chemical durability.展开更多
Artificial intelligence(AI)is reshaping financial systems and services,as intelligent AI agents increasingly form the foundation of autonomous,goal-driven systems capable of reasoning,learning,and action.This review s...Artificial intelligence(AI)is reshaping financial systems and services,as intelligent AI agents increasingly form the foundation of autonomous,goal-driven systems capable of reasoning,learning,and action.This review synthesizes recent research and developments in the application of AI agents across core financial domains.Specifically,it covers the deployment of agent-based AI in algorithmic trading,fraud detection,credit risk assessment,roboadvisory,and regulatory compliance(RegTech).The review focuses on advanced agent-based methodologies,including reinforcement learning,multi-agent systems,and autonomous decision-making frameworks,particularly those leveraging large language models(LLMs),contrasting these with traditional AI or purely statistical models.Our primary goals are to consolidate current knowledge,identify significant trends and architectural approaches,review the practical efficiency and impact of current applications,and delineate key challenges and promising future research directions.The increasing sophistication of AI agents offers unprecedented opportunities for innovation in finance,yet presents complex technical,ethical,and regulatory challenges that demand careful consideration and proactive strategies.This review aims to provide a comprehensive understanding of this rapidly evolving landscape,highlighting the role of agent-based AI in the ongoing transformation of the financial industry,and is intended to serve financial institutions,regulators,investors,analysts,researchers,and other key stakeholders in the financial ecosystem.展开更多
Industrial waste salts are commonly used to make value-added snow-melting agents to ensure traffic safety in northern China during winter and spring after snowfall.However,heavy metals in industrial waste salts may po...Industrial waste salts are commonly used to make value-added snow-melting agents to ensure traffic safety in northern China during winter and spring after snowfall.However,heavy metals in industrial waste salts may pose certain environmental risks.Snow-melting agents and snow samples were collected and analyzed from highways,arterial roads,footbridges,and other locations in Beijing after the snowstorm in December 2023.It was found that the main component of snow-melting agents was sodium chloride with high concentrations of Cu,Mn,and Zn,which are not regulated in the current policies,despite the recent promotion of environmentally friendly snow-melting agents.The Pb,Zn and Cr contents of some snow samples exceeded the limitation value of surface water quality standards,potentially affecting the soil and water environment near roadsides,although the snow-melting agents comply with relevant standards,which indicates the policy gap in the management of recycled industrial salts.We reviewed and analyzed the relevant standards for snow-melting agents and industrial waste salts proposed nationally and internationally over the past 30 years.Through comparative analysis,we proposed relevant policy recommendations to the existing quality standards of snow-melting agents and the management regulations of industrial waste salts,and the formulation of corresponding usage strategies,aimed at reducing the potential environmental release of heavy metals from the use of snow-melting agents,thereby promoting more sustainable green urban development and environmentally sound waste management.展开更多
基金financially supported by the National Natural Science Foundation of China(No.21304070)Natural Science Foundation of Tianjin City(No.15JCYBJC47300)+1 种基金Major Program of National Natural Science Foundation of China(No.11432016)the Municipal Key Program of Natural Science Foundation of Tianjin(No.14JCZDJC40700)
文摘Zinc phenylphosphonate （PPZn）, a benign and biocompatible nucleating agent, was prepared and incorporated into the biodegradable poly（ethylene adipate） （PEA） to investigate its effect on the crystallization behavior, crystallization kinetics and spherulite morphology of PEA. Upon addition of PPZn, the crystallization temperature and crystallinity of PEA in the non-isothermal crystallization process increased significantly. Analysis of crystallization kinetics by Avrami equation suggests that the crystallization time shortened greatly and crystallization rate increased markedly after addition of PPZn. In the presence of PPZn, the spherulite size decreased and spherulite density increased significantly. It suggests that PPZn is an efficient nucleating agent for the crystallization of PEA. The accelerated crystallization in the presence of PPZn is mainly attributed to the epitaxial nucleation of PEA crystals on the surface of PPZn crystals, that is, a perfect lattice matching between PEA crystal and PPZn crystal occurs.
基金Funded by the National Natural Science Foundation of China(No.50472309)
文摘The crystallization behavior and transparent property of MgO-A1203-SiO2 （MAS） glasses with TiO2 and TiO2＋ZrO2 as nucleating agents were discussed by differential thermal analysis, X-ray diffraction, field emission-environment scanning electron microscope, energy dispersive spectrum and UV-VIS-NIR scanning spectrophotometer. It was found that the glass crystallized at 950 ℃ with ZrO2 less than 3% could obtain transparent glass ceramic, which presented purple to colorless. With the nucleating agent additives （5% TIO2＋3% ZrO2）, the colorless transparent glass-ceramics with spinel as the main crystal phase could be prepared, and the transmittance reached about 80%. As the crystallized temperature increase to 1 000 ℃, besides spinel（MgA1204）, sapphirine （Mg3.5A19Si1.5O20） and ZrTiO4 precipitated from matrix glass, and the transmitance of glass-ceramic decreased.
基金Supported by the National Natural Science Foundation of China （20876042） Program of Shanghai Subject Chief Scientist （10XD1401500） Research Fund for the Doctoral Program of Higher Education of China
文摘The effect of a novel active nucleating agent(TBC8-eb) on the isothermal crystallization of poly(L-lactic acid) (PLLA) was studied by differential scanning calorimetry(DSC) and Fourier transform infrared spectroscopy(FTIR) . The analysis on kinetics demonstrates that TBC8-eb can not only accelerate the crystallization rate but also transform most of the original spherulite crystals of PLLA into sheaf-like crystals. Furthermore,the free energy of folding(σe) of PLLA and PLLA with TBC8-eb is 0.15 and 0.06 J·m-2,respectively,which suggests that the addition of TBC8-eb favors the regular folding of molecule chains in the crystallization of PLLA,improv-ing its crystallization rate. The FTIR results show that TBC8-eb can accelerate the conformational ordering of PLLA in the isothermal crystallization. The conformational ordering of PLLA nucleated with TBC8-eb begins with the interchain interaction of CH3,and then a short helix emerges where a couple of CH3 groups interact.
文摘It is deduced from thermodynamic relations and confirmed by experiment results that the nucleation rate and nucleation temperature of nucleating agents in the glass are dependent upon their melting entropy Delta S//m melting temperature T//m and crystal - type transition in terms of some mathematical expressions. (Author abstract) 10 Refs.
文摘An aryl dicarboxylic acid amide compound TMB-5 is an efficient β-form nucleating agent for isotactic polypropylene （iPP）. Because of the solubility of TMB-5, superstructure and morphology of iPP crystals changed with melting conditions. Effects of final heating temperature （Tf） on heterogeneous nucleation of iPP/TMB-5 were investigated. It was discovered that the crystallization temperature increased with decreasing Tf value. The optical microscopic images indicated that when TMB-5 partially dissolved in iPP melt, the remaining （non-dissolved） TMB-5 facilitated the recrystallization of dissolved nucleating agent from the melt, which promoted crystallization. Complete solubility of nucleating agent caused the decreasing efficiency. TMB-5 recrystallized in the form of tiny needles, whose aggregates induced dendritic iPP crystals.
基金financially supported by the National Natural Science Foundation of China(No.50803042)Chengdu Economic & Technological Development Zone and Chuanlu Group
文摘Although addition of β-nucleating agent directly into homo-polypropylene （PPH） is a useful method to improve ,β-crystal content and toughen PPH, polypropylene random copolymer （PPR） makes this method powerless due to its random structure and low crystallinity. In this study, the β-nucleated PPR with high β-crystal content was prepared by a novel high effective β-nucleating system which consists of β-nucleation agent （TMB-5） and modified zeolite 13X （M13X）. It was found that M13X and TMB-5 had a synergistic influence on improving β-crystal content and toughening PPR. The content of β-crystal in PPR/M13X/TMB-5 was significantly larger than the sum of that in PPR/M13X and PPR/TMB-5. Besides, fracture behavior, phase morphology and relaxation of matrix chain segments were also investigated. The results showed that M13X and TMB-5 improved the mobility of amorphous chain segments at low temperature and contributed to much energy dissipation. This work provides a powerful method to modify PPR.
文摘The melting behavior of polypropylene (PP) and low ethylene content polypropylenecopolymer with and without nucleating agent samples crystallized under both isothermal and non-isothermal conditions were studied by Differential Scanning Calorimeter (DSC) and X-raydiffraction. Multiple melting behavior were observed depending on the existence of nucleatingagent and crystallization conditions. The observed phenomena have been discussed by the effect ofnucleating agent on perfection of crystal and the melting and recrystallization of imperfect crystalto a more perfect crystal during the heating process of samples.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.52073261 and U1704162).
文摘Poly(butylene adipate-co-terephthalate)(PBAT)is a promising biodegradable flexible polymer but suffers from slow crystallization rate,making it less attractive for some applications like the injection-molded products in comparison with low-density polyethylene(LDPE).This work aimed to accelerate the crystallization of PBAT by adding a self-assembly nucleating agent octamethylenedicarboxylic dibenzoylhydrazide(OMBH).PBAT/OMBH composites with various OMBH contents(0 wt%,0.5 wt%,0.7 wt%,1 wt%,2 wt%,3 wt%and 5 wt%)were prepared through melt-mixing.The effect of OMBH on the crystallization behavior,morphologies and mechanical properties of PBAT was investigated.The highest nucleation efficiency value of 59.6%was achieved for PBAT with 0.7 wt%OMBH,much higher than that of 22.7%for PBAT with 0.7 wt%talc.Atomic force microscopy results showed that OMBH formed fine fibers and induced the formation of transcrystalline layers of PBAT.Fourier transform infrared spectroscopy(FTIR)combined with two-dimensional correlation spectra suggested that the intermolecular dipole-dipole N—H…O=C interactions but not hydrogen bond between OMBH and PBAT promoted the crystallization of PBAT in the initial period of crystallization.The presence of OMBH did not change the crystal form of PBAT but had positive contribution in enhancing its crystallinity and mechanical properties.This work is essential for preparing PBAT with high crystallization rate,enhancing its potential applications in injection-molded products.
基金supported by the National Natural Science Foundation of China(Nos.51573131,51173130,21274149 and 21374077)
文摘The crystalline structures and crystallization behaviors of iPP containing β nucleation agent TMB-5 （iPP/TMB-5） were investigated by synchrotron radiation wide angel X-ray diffraction （SR-WAXD）, differential scanning calorimeter （DSC） and polarized light microscope （PLM）. It was found that α-crystallization lagged behind β-crystallization at normal temperatures, but the discrepancy reduced with increasing temperature. TMB-5 could not induce β-iPP when the nucleation agent is wrapped up with α-crystal that crystallized at high temperatures. The polymorphic composition of iPP/TMB-5 was susceptible to the introductory moment of shear. New crystallization process of β-nucleated iPP was proposed to understand the experimental phenomena which could not be explained by those reported in the literature. It was supposed that polymer crystallization initiated from mesophase, and the formations of iPP crystals involved the organization of helical conformation ordering within rnesophase. It was proposed that the iPP melt contained mesophases with stereocomplex-type ordering of right-handed and left-handed helical chains which could be disturbed by shear or TMB-5, leading to different polymorphic structures.
基金an International Cooperation Research Program，key project from National Science Foundation of China for multiscale methodology，SINOPEC supported fundamental research project，an Association Franco-Chinoise pour la Recherche Scientifique et Technique(AFCRST) supported project
文摘Impregnation of isotactic polypropylene (iPP) with nucleating agent (NA21) using supercritical carbon dioxide as the swelling agent at different temperature and pressure and its non-isothermal crystallization kinetics were investigated. The results showed that NA21 was dispersed at a nanometer-scale in the PP matrix, resulting in the formation of different typesof crystal phases of iPP and the enhancement of its mechanical properties.
基金financially supported by‘‘the Fundamental Research Funds for the Central Universities’’(2572015AB07)the Forestry Industry Research of China(No.201204802)the National Natural Science Foundation of China(No.31100425)
文摘The influence of aryl amide compounds（TMB）as b-nucleating agents, on the non-isothermal crystallization of a wood-flour/polypropylene composite（WF/PP）prepared by compression molding was investigated by wide-angle X-ray diffraction and differential scanning calorimetry. TMB was proved to be an effective b-crystalline nucleating agent for WF/PP. The DSC data showed that the crystallization peak temperature（Tp） increased and the half-time（t1/2） decreased with the addition of TMB.Three theoretical models were used to analyze the nonisothermal crystallization process. The modified Avrami method and Mo method successfully explained the nonisothermal crystallization behavior of PP and its composites. Their activation energies for non-isothermal crystallization were determined basing on the Kissinger method.
基金Funded by the Natural Science Foundation of Liaoning Province of China(No.20180550432)Natural Science Foundation for Young Doctoral Research(No.2020-BS-158)Basic Scientific Research Project of Colleges and Universities of Liaoning Provincial Department of Education(No.LJKQZ2021060)。
文摘A novel polypropylene random(PPR)composite materials with optimized properties was developed by addingβ-nucleating compound agents(rare earth complex WBG-2 and aryl amide derivative TMB-5)and ternary compound modifier(TPE/WBG-2/CaCO_(3)).The effects of differentβ-nucleating agents and ternary compound modifier on the mechanical properties and crystallization behavior of PPR were analyzed.The results show that,compared with pure PPR materials,both WBG-2 and TMB-5 could significantly improve the impact strength of PPR.The crystallization temperature of PPR increased with the addition ofβ-nucleating agent.The modified PPR prepared with ternary compound modifier showed the most excellent comprehensive properties.
基金financially supported by the National Natural Science Foundation of China(Nos.11432003 and 11572290)Young Teacher Project of Zhongyuan University of Technology(No.2019XQG05)。
文摘Herein,isotactic polypropylene films with smallβ-nucleating agent content were fabricated via a melt-extrusion-stretched technology with intended"shear-free"in barrel and die.Compared with neat films,the tensile strength,elongation at break and strain energy density at break of i PP film with 0.05 wt%β-nucleating agent are significantly improved by 13.8%,39.6%and 90.6%,respectively,indicating the simultaneously enhanced toughness and strength.Additionally,theβ-crystal content gradually increases with increasingβ-NA content,while the relative total daughter content ofα-andβ-crystal exhibits opposite tendency.Moreover,nucleation and crystal growth induced by variousβ-NA contents are different.This work proves an efficient strategy to enhance mechanical properties of isotactic polypropylene film via controlling elongation flow and addition of appropriateβ-NA content.
基金Funded by The National Key Technology R & D Program of China for the 11th Five-Year Plan(2006BAJ04A04)
文摘Glass ceramics was made by the one-time sintering method using the main raw material of iron tailings. On the basis of quaternary system of CaO-MgO-Al2O3-SiO2, using DTA, XRD and SEM, the effects of different nucleating agents and mixing amounts as well as heat treatment on the crystallization of railings glass ceramics were studied. The experimental results show that, nucleating agent and heat treatment are two necessary conditions for one-time sintering preparation of tailings glass ceramics namely, only adding nucleating agent or experiencing heat treatment, the quaternary system can not crystallize. The composite nucleating agent consisting of Cr2O3 and TiO2 can further lead to the crystallization of the CaO-MgO-A1203-SiO2 quaternary system at the lower temperature, with the major phase of diopside. In the range of mass content, 0%-4%, crystal intensity and crystal content grow. But when mass content is more than 4%, the crystal size will become coarser and the crystal distribution will be less regular. Different heat treatment regimes do not change the composition of the crystalline major phase in the glass ceramics crystallization of CaO-MgO-Al2O3-SiO2 system. In the range of 30-60 minutes, with the extension of nucleation and crystallization, crystallization degree enhanced, but if the holding time surpasses 60 minutes, the crystallization is worse.
基金financially supported by the National Natural Science Foundation of China(Nos.51373020,51573016 and 51521062)
文摘The influence of cyanuric acid（CA） as an efficient nucleating agent on the crystallization behavior and morphology of biodegradable poly（ε-caprolactone）（PCL） was extensively studied in this work with several techniques for the first time. The nonisothermal melt crystallization behavior and overall isothermal melt crystallization rate of PCL were significantly enhanced by only a small amount of CA. The addition of CA apparently improved the nonisothermal melt crystallization peak temperature, overall isothermal melt crystallization rate, and nucleation density of PCL spherulites, but did not modify the crystallization mechanism and crystal structure of PCL, indicating that CA was an efficient nucleating agent for the crystallization of PCL. The possible nucleation mechanism of CA on the crystallization of PCL was also discussed on the basis of their crystal structures.
基金the National Natural Science Foundation of China (No. 50972116)
文摘The reference test methods are carried out parallelly, by means of chemical analysis, X-ray diffraction, differential scanning calorimetry-thermogravimetry, scanning electron microscopy and polarized optical microscope to study the formation of C4A3S in the presence and absence of nucleating agent. The results show that nucleating agent with high calcium and low heat consumption as tricalcium silicate （C3S） promotes the formation of C4A3S and increases desulfurization degree obviously. During calcining raw meals doped with C3S, the grain sizes of C4A3S are larger compared with that without C3S. And at the same calcining level, the mass loss and the heat consumption belonged to CaCO3 decomposition is reduced.
基金supported by the National Natural Science Foundation of China(No.52003280)the Zhejiang Provincial Natural Science Foundation of China(No.LQ21B040003)+1 种基金the S&T Innovation 2025 Major Special Programme of Ningbo(No.2021Z052)the Chinese Academy of Sciences Pioneer Hundred Talents Program.
文摘Poly(lactide acid)(PLA)foams have shown considerable promise as eco-friendly alternatives to nondegradable plastic foams,such as polystyrene(PS)foams.Nevertheless,PLA foam typically suffers from low heat-resistance and poor cellular structure stemming from its inherent slow crystallization rate and low melt strength.In this study,a high-performance PLA foam with well-defined cell morphology,exceptional strength and enhanced heat-resistance was successfully fabricated via a core-back microcellular injection molding(MIM)process.Differential scanning calorimetry(DSC)results revealed that the added hydrazine-based nucleating agent(HNA)significantly increased the crystallization temperature and accelerated the crystallization process of PLA.Remarkably,the addition of a 1.5 wt%of HNA led to a significant reduction in PLA’s cell size,from 43.5µm to 2.87µm,and a remarkable increase in cell density,from 1.08×10^(7)cells/cm^(3)to 2.15×10^(10)cells/cm^(3).This enhancement resulted in a final crystallinity of approximately 55.7%for the PLA blend foam,a marked improvement compared to the pure PLA foam.Furthermore,at 1.5 wt%HNA concentration,the tensile strength and tensile toughness of PLA blend foams demonstrated remarkable improvements of 136%and 463%,respectively.Additionally,the Vicat softening temperature of PLA blend foam increased significantly to 134.8°C,whereas the pure PLA foam exhibited only about 59.7℃.These findings underscore the potential for the preparation of lightweight injection-molded PLA foam with enhanced toughness and heat-resistance,which offers a viable approach for the production of high-performance PLA foams suitable for large-scale applications.
基金Supported by the National Natural Science Foundation of China(No.51378332 and No.20806051)Science and Technology Project of Housing and Urban-Rural Ministry(No.2014-K4-014)Chinese Postdoctoral Science Foundation(No.2013M530872)
文摘Glass-ceramics obtained from the electric arc furnace molten slag of incinerator fly ash was produced by applying nucleation and crystallization through heat treatment process. The effects of nucleating agent （TiO2 and Cr2O3） on the crystallization kinetics and heat treatment schedule of the slag were investigated. The results show that the nucleating agents changed the crystallization phase and morphology of the obtained glass-ceramics. The optimum heat treatment schedule of the glass with TiO2 was determined as nucleation at 952 K for 1.5 h and crystal growth at 1 258 K for 1.5 h, while those values with Cr203 were estimated at 971 K for 2 h and at 1 238 K for 2 h. TiO2 acting as nucleating agent could decrease the activation energy of the slag and shorten the total thermal treatment time in comparison with Cr2O3. The glass-ceramics obtained under the optimum heat treatment condition was environmentfriendly and had remarkable physical/mechanical properties and chemical durability.
基金supported by the Ministry of Education and Science of the Republic of North Macedonia through the project“Utilizing AI and National Large Language Models to Advance Macedonian Language Capabilties”。
文摘Artificial intelligence(AI)is reshaping financial systems and services,as intelligent AI agents increasingly form the foundation of autonomous,goal-driven systems capable of reasoning,learning,and action.This review synthesizes recent research and developments in the application of AI agents across core financial domains.Specifically,it covers the deployment of agent-based AI in algorithmic trading,fraud detection,credit risk assessment,roboadvisory,and regulatory compliance(RegTech).The review focuses on advanced agent-based methodologies,including reinforcement learning,multi-agent systems,and autonomous decision-making frameworks,particularly those leveraging large language models(LLMs),contrasting these with traditional AI or purely statistical models.Our primary goals are to consolidate current knowledge,identify significant trends and architectural approaches,review the practical efficiency and impact of current applications,and delineate key challenges and promising future research directions.The increasing sophistication of AI agents offers unprecedented opportunities for innovation in finance,yet presents complex technical,ethical,and regulatory challenges that demand careful consideration and proactive strategies.This review aims to provide a comprehensive understanding of this rapidly evolving landscape,highlighting the role of agent-based AI in the ongoing transformation of the financial industry,and is intended to serve financial institutions,regulators,investors,analysts,researchers,and other key stakeholders in the financial ecosystem.
基金supported by the National Natural Science Foundation of China(No.22176200)the Industrial Innovation Entrepreneurial Team Project of Ordos 2021.
文摘Industrial waste salts are commonly used to make value-added snow-melting agents to ensure traffic safety in northern China during winter and spring after snowfall.However,heavy metals in industrial waste salts may pose certain environmental risks.Snow-melting agents and snow samples were collected and analyzed from highways,arterial roads,footbridges,and other locations in Beijing after the snowstorm in December 2023.It was found that the main component of snow-melting agents was sodium chloride with high concentrations of Cu,Mn,and Zn,which are not regulated in the current policies,despite the recent promotion of environmentally friendly snow-melting agents.The Pb,Zn and Cr contents of some snow samples exceeded the limitation value of surface water quality standards,potentially affecting the soil and water environment near roadsides,although the snow-melting agents comply with relevant standards,which indicates the policy gap in the management of recycled industrial salts.We reviewed and analyzed the relevant standards for snow-melting agents and industrial waste salts proposed nationally and internationally over the past 30 years.Through comparative analysis,we proposed relevant policy recommendations to the existing quality standards of snow-melting agents and the management regulations of industrial waste salts,and the formulation of corresponding usage strategies,aimed at reducing the potential environmental release of heavy metals from the use of snow-melting agents,thereby promoting more sustainable green urban development and environmentally sound waste management.
