Polyvinyl chloride(PVC)poses persistent environmental and recycling challenges due to its high chlorine content,complex additives,and structural resistance to degradation.Recent research has shifted focus from traditi...Polyvinyl chloride(PVC)poses persistent environmental and recycling challenges due to its high chlorine content,complex additives,and structural resistance to degradation.Recent research has shifted focus from traditional disposal methods toward chemically informed strategies that valorize PVC within the framework of a circular economy.This review systematically summarizes three emerging pathways for PVC transformation.The first involves catalytic deconstruction into small molecules such as chlorinated olefins,hydrocarbons,and oxygenates through thermal,photocatalytic,and electro-assisted processes.The second explores backbone-preserving reconstruction into functional materials,including porous carbons,membranes,ion-conducting films,and vitrimer-type polymers by leveraging selective dechlorination and structural reprogramming.The third addresses the co-processing of PVC with mixed plastic wastes through synergistic catalytic systems that tolerate chlorine-rich streams and promote selective transformation.Across all pathways,emphasis is placed on structure-property correlations,chlorine management,additive compatibility,and downstream utility.Summary tables and schematic diagrams are included to compare system efficiencies,product selectivities,and application scopes.By integrating mechanistic understanding with materials innovation,this review highlights how PVC can be reimagined as a tunable molecular platform rather than a persistent pollutant.展开更多
Recycling plastic waste into triboelectric nanogenerators(TENGs)presents a sustainable approach to energy harvesting,self-powered sensing,and environmental remediation.This study investigates the recycling of polyviny...Recycling plastic waste into triboelectric nanogenerators(TENGs)presents a sustainable approach to energy harvesting,self-powered sensing,and environmental remediation.This study investigates the recycling of polyvinyl chloride(PVC)pipe waste polymers into nanofibers(NFs)optimized for TENG applications.We focused on optimizing the morphology of recycled PVC polymer to NFs and enhancing their piezoelectric properties by incorporating ZnO nanoparticles(NPs).The optimized PVC/0.5 wt%ZnO NFs were tested with Nylon-6 NFs,and copper(Cu)electrodes.The Nylon-6 NFs exhibited a power density of 726.3μWcm^(-2)—1.13 times higher than Cu and maintained 90%stability after 172800 cycles,successfully powering various colored LEDs.Additionally,a 3D-designed device was developed to harvest energy from biomechanical movements such as finger tapping,hand tapping,and foot pressing,making it suitable for wearable energy harvesting,automatic switches,and invisible sensors in surveillance systems.This study demonstrates that recycling polymers for TENG devices can effectively address energy,sensor,and environmental challenges.展开更多
Polyvinyl chloride(PVC)is one of the most widely used plastic materials worldwide,particularly in long-life applications such as construction materials.However,recycling options for PVC waste remain limited,as convent...Polyvinyl chloride(PVC)is one of the most widely used plastic materials worldwide,particularly in long-life applications such as construction materials.However,recycling options for PVC waste remain limited,as conventional methods often degrade material quality or generate environmentally hazardous byproducts.In this study,we demonstrate an efficient process to convert PVC into new polymers with variable aromatic groups,using triethylsilane as the reductant in different solvents.This approach enables the production of polymers analogous to functionalized polyethylene(PE),which are typically challenging to obtain through conventional copolymerization or direct post-modification of C-H bonds in PE.The resulting polymers exhibit tunable thermal and mechanical properties depending on the introduced aromatic groups,which not only enhance the sustainable valorization of PVC waste,but also provide an opportunity for the synthesis of new functionalized polymers.展开更多
Surface of TiO2 nanoparticles was modified with the in situ chemical oxidative polymerization of aniline. Polyaniline modified TiO2 nanoparticles （PANI-TiO2） were characterized with the FT-IR, XRD, SEM and TEM techn...Surface of TiO2 nanoparticles was modified with the in situ chemical oxidative polymerization of aniline. Polyaniline modified TiO2 nanoparticles （PANI-TiO2） were characterized with the FT-IR, XRD, SEM and TEM techniques. Results confirmed that PANI was grafted successfully on the surface of TiO2 nanoparticles, therefore agglomeration of nanoparticles decreased dramatically. Polyvinyl chloride nanocomposites filled with 1 wt%-5 wt% of PANI-TiO2 and TiO2 nanoparticles were prepared via the solution blending method. PVC nanocomposites were analyzed with FT-IR, XRD, SEM, TG/DTA, DSC and tensile test techniques. Effect of PANI as surface modifier of nanoparticles was discussed according to the final properties of PVC nanocomposites. Results demonstrated that deposition of PANI on the surface of TiO2 nanoparticles improved the interfacial adhesion between the constituents of nanocomposites, which resulted in better dispersion of nanoparticles in the PVC matrix. Also PVC/PANI-TiO2 nanocomposites showed higher thennal resistance, tensile strength and Young＇s modulus compared to those of unfilled PVC and PVC/TiO2 nanocomposites.展开更多
To effectively improve the performance and expand the applications of polymers, molecular dynamics(MD) simulations with the COMPASS force field have been applied to predict the miscibility, glass transition temperatur...To effectively improve the performance and expand the applications of polymers, molecular dynamics(MD) simulations with the COMPASS force field have been applied to predict the miscibility, glass transition temperature(Tg), and mechanical properties of poly(vinyl chloride)/dioctyl phthalate(PVC/DOP) blends. The solubility parameter values obtained are in good agreement with the reference data and the little difference(|Δδ|< 2.0 MPa0.5) between two components indicates that PVC/DOP is a miscible system. Tg is predicted by the slope of the free volume and density versus temperature simulation data based on density and free volume theory which is agree well with the experimental data. In addition, the analyses of mechanical properties results indicate that the values of Young’s modulus(E), bulk modulus(K), and shear modulus(G) decrease with the addition of DOP, demonstrating that the rigidity of material is weakened and the ductility is improved. The mechanical properties can also be effectively improved by increasing the temperature, which may provide a more flexible mixture, with lower E, K, G but an increased ductility.展开更多
Acetanilide, adipic acid and potassium hydrogen phthalate were chosen as nucleating agents of polyvinyl chloride（PVC）, and their effects on PVC crystallization were studied by differential scanning calorimetry, wide...Acetanilide, adipic acid and potassium hydrogen phthalate were chosen as nucleating agents of polyvinyl chloride（PVC）, and their effects on PVC crystallization were studied by differential scanning calorimetry, wide angle X-ray diffraction and fourier transform infrared spectroscopy. The experimental results indicate that all of the three additives are compatible with PVC to some extent, but adipic acid＇s compatibility with PVC is less satisfactory. The three additives can improve PVC crystallinity, and acetanilide can decrease PVC glass transition temperature（T）and narrow PVC melting range, while adipic acid and potassium hydrogen phthalate rise T of PVC and widen its melting range. All additives do not affect PVC crystal system and all g samples are in orthorhombic system. All additives can improve （200）, （110）, （210） and （201, 111） planes growing. Moreover, acetanilide and adipic acid can shrink PVC spacings and improve the crystal perfection of PVC, but potassium hydrogen phthalate swells spacings and reduces the perfection of PVC crystal.展开更多
A calcium sulfate whisker （CSW） coated with glutaraldehyde crosslinked chitosan （GACS） was prepared to reinforce polyvinyl chloride （PVC） in this study. The results show that the optimum concentration of both ch...A calcium sulfate whisker （CSW） coated with glutaraldehyde crosslinked chitosan （GACS） was prepared to reinforce polyvinyl chloride （PVC） in this study. The results show that the optimum concentration of both chitosan （CS） and glutaraldehyde （GA） is 0.05 wt%. The tensile strength, impact strength, flexural modulus and vicat softening temperature of the PVC composite with 12 wt% of modified CSW are in- creased by 1 Z5%, 40.4%, 0.8% and 3.8% compared with those of the PVC composite with 12 wt~ of unmodified CSW, and by 2.9%, 42.4%, 2Z1% and 6.8% compared with those of pure PVC, respectively. The dynamic mechanical analysis results indicate that the modified CSW/PVC composite exhibits much higher storage modulus and glass transition temperature than those of unmodified CSW/PVC composite and pure PVC. In addition, the modified CSW/PVC composite also demonstrates good thermal properties with a high rapidest decomposition temperature （Trvd） and char residue. The scanning electron microscopy images of tensile-fractured surfaces show that the modified CSW has a strong interfacial adhesion with PVC matrix.展开更多
Thermogravimetric study of medical transfusion tube （MTT） waste containing polyvinyl chloride （PVC） was carried out using the thermogravimetric analyser （TGA） with N2, at different heating rates of 5, 10, 20, 30...Thermogravimetric study of medical transfusion tube （MTT） waste containing polyvinyl chloride （PVC） was carried out using the thermogravimetric analyser （TGA） with N2, at different heating rates of 5, 10, 20, 30, 50 ℃/min. The purpose is to obtain pyrolysis characteristics and kinetic parameters of medical waste. The experimental results indicate that the pyrolysis behavior of the MTT sample is in agreement with its main ingredient of PVC, appearing two stair stepping stages. The influence of the additives in MTT on pyrolysis behavior was also revealed, which could improve MTT pyrolysis at lower temperature in the first stage, and cause obvious unsmoothness and asymmetry of the second DTG peak. Four n-order kinetic models of Coats-Redfern, Ozawa, Kissinger and Freeman-carroll were used to get the kinetic parameters. Furthermore, a novel ＂two-step four-reaction model＂ was established to simulate the whole continuous process. The different methods and the kinetic parameters thus obtained were discussed and compared with each other in literatures. The reasons of deviation among kinetic values were tried to be elucidated. The new established model could more satisfactorily describe the pyrolysis process of MTT, being more mechanistic and conveniently serving for the engineering.展开更多
To enhance the blood compatibility of Polyvinyl Chloride (PVC) film, the film was modified by SO2/O2 gas plasma treatment. The effect of surface sulfonation of PVC treated by various SO2/O2 gas plasma depended on the ...To enhance the blood compatibility of Polyvinyl Chloride (PVC) film, the film was modified by SO2/O2 gas plasma treatment. The effect of surface sulfonation of PVC treated by various SO2/O2 gas plasma depended on the volume ratio O2/(SO2 +O2). When the volume ratio was 0.5, the effect of sulfonation was the best. Sulfonic acid groups were specifically and efficiently introduced onto the PVC surface, which was proved by X-ray photoelectron spectroscopy (XPS) and Attenuated Total Reflectance Fourier Transfer Infrared (ATR-FTIR) spectroscopy. The surface microstructure of modified PVC film was studied with scanning electron microscopy (SEM). The antithrombogenicity of the samples was determined by the activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT) and plasma recalcification time (PRT) tests and platelet adhesion experiment. The results indicated that the antithrombogenicity of modified PVC was improved remarkably.展开更多
The development of recycled aggregate concrete(RAC)provides a new approach to limiting the waste of natural resources.In the present study,the mechanical properties and deformability of RACs were improved by adding ba...The development of recycled aggregate concrete(RAC)provides a new approach to limiting the waste of natural resources.In the present study,the mechanical properties and deformability of RACs were improved by adding basalt fibers(BFs)and using external restraints,such as a fiber-reinforced polymer(FRP)jacket or a PVC pipe.Samples were tested under axial compression.The results showed that RAC(50%replacement of aggregate)containing 0.2%BFs had the best mechanical properties.Using either BFs or PVC reinforcement had a slight effect on the loadbearing capacity and mode of failure.With different levels of BFs,the compressive strengths of the specimens reinforced with 1-layer and 3-layer basalt fiber reinforced polymer(BFRP)increased by 6.7%–10.5%and 16.5%–23.7%,respectively,and the ultimate strains increased by 48.5%–80.7%and 97.1%–141.1%,respectively.The peak stress of the 3-layer BFRP-PVC increased by 42.2%,and the ultimate strain improved by 131.3%,relative to the control.This reinforcement combined the high tensile strength of BFRP,which improved the post-peak behavior,and PVC,which enhanced the structural durability.In addition,to investigate the influence of the various constraints on compressive behavior,the stress-strain response was analyzed.Based on the analysis of experimental results,a peak stress-strain model and an amended ultimate stress-strain model were proposed.The models were verified as well;the result showed that the predictions from calculations are generally consistent with the experimental data(error within 10%).The results of this study provide a theoretical basis and reference for future applications of fiber-reinforced recycled concrete.展开更多
In the prevailing incineration processes of municipal solid waste,the presence of polyvinyl chloride(PVC)may cause environmental problems.The energy-intensive ironmaking sector in the iron and steel industry operates ...In the prevailing incineration processes of municipal solid waste,the presence of polyvinyl chloride(PVC)may cause environmental problems.The energy-intensive ironmaking sector in the iron and steel industry operates at high temperature and under high reduction potential with the function of energy conversion,which can provide a potential path for the collaborative utilization of waste plastics in large quantities and low cost.The gasification of the char formed from PVC when processed in the ironmaking sector is significant for the development of the related technologies.Thus,the gasification experiment of PVC char and traditional carbonaceous materials was performed by thermogravimetric analysis.The results indicated that the gasification ability decreased in the sequence of PVC char>anthracite coal>coke>graphite.Then,kinetics were also analyzed by Coats-Redfern and Doyle approximations.The PVC char showed the best gasification ability with the smallest activation energy,ranging from 87.18 to 117.52 kJ/mol,and the smaller graphitization degree of PVC char compared with other carbonaceous materials should be the main reason for its excellent gasification reactivity.展开更多
Chemically functionalized carbon nanotubes were combined with PVC to enhance both toughness and strength by simply mixing long alkyl chain modified multi-wall carbon nanotubes (abbreviated as MWNTs) or Ester-functiona...Chemically functionalized carbon nanotubes were combined with PVC to enhance both toughness and strength by simply mixing long alkyl chain modified multi-wall carbon nanotubes (abbreviated as MWNTs) or Ester-functionalized soluble MWNTs (abbreviated as eMWNTs) with PVC in Tetrahydrofuran (THF)/Cyclohexanone (CH) solution to obtain good dispersity solution. The MWNTs modified with 1-Bromohexadecane can effectively increase the intermolecular force with PVC by hydrogen bond. The obtained nanocomposite has a regular shape with homogeneously dispersed particles. PVC/2 wt% eMWNTs has been proved to possess excellent thermal stability. The intermolecular force between eMWNTs and PVC endows the as-fabricated nanocomposite with enhanced toughness and strength, indicating that our method is promising for wide use in PVC/eMWNTs nanocomposition.展开更多
基金supported by the National Natural Science Foundation of China(22125103)the Science and Technology Commission of Shanghai Municipality(No.22JC140100)PhD Scientific Research and Innovation Foundation of the Education Department of Hainan Province Joint Project of Sanya Yazhou Bay Science and Technology City(grant number HSPHDSRF-2024-14-003).
文摘Polyvinyl chloride(PVC)poses persistent environmental and recycling challenges due to its high chlorine content,complex additives,and structural resistance to degradation.Recent research has shifted focus from traditional disposal methods toward chemically informed strategies that valorize PVC within the framework of a circular economy.This review systematically summarizes three emerging pathways for PVC transformation.The first involves catalytic deconstruction into small molecules such as chlorinated olefins,hydrocarbons,and oxygenates through thermal,photocatalytic,and electro-assisted processes.The second explores backbone-preserving reconstruction into functional materials,including porous carbons,membranes,ion-conducting films,and vitrimer-type polymers by leveraging selective dechlorination and structural reprogramming.The third addresses the co-processing of PVC with mixed plastic wastes through synergistic catalytic systems that tolerate chlorine-rich streams and promote selective transformation.Across all pathways,emphasis is placed on structure-property correlations,chlorine management,additive compatibility,and downstream utility.Summary tables and schematic diagrams are included to compare system efficiencies,product selectivities,and application scopes.By integrating mechanistic understanding with materials innovation,this review highlights how PVC can be reimagined as a tunable molecular platform rather than a persistent pollutant.
基金supported by the research projects AP23486880 from the Ministry of Higher EducationScience of the Republic of Kazakhstan and 111024CRP2010,20122022FD4135 from Nazarbayev University.
文摘Recycling plastic waste into triboelectric nanogenerators(TENGs)presents a sustainable approach to energy harvesting,self-powered sensing,and environmental remediation.This study investigates the recycling of polyvinyl chloride(PVC)pipe waste polymers into nanofibers(NFs)optimized for TENG applications.We focused on optimizing the morphology of recycled PVC polymer to NFs and enhancing their piezoelectric properties by incorporating ZnO nanoparticles(NPs).The optimized PVC/0.5 wt%ZnO NFs were tested with Nylon-6 NFs,and copper(Cu)electrodes.The Nylon-6 NFs exhibited a power density of 726.3μWcm^(-2)—1.13 times higher than Cu and maintained 90%stability after 172800 cycles,successfully powering various colored LEDs.Additionally,a 3D-designed device was developed to harvest energy from biomechanical movements such as finger tapping,hand tapping,and foot pressing,making it suitable for wearable energy harvesting,automatic switches,and invisible sensors in surveillance systems.This study demonstrates that recycling polymers for TENG devices can effectively address energy,sensor,and environmental challenges.
基金the Beijing Natural Science Foundation(Z240029)the National Natural Science Foundation of China(22472004)+2 种基金China National Petroleum Corporation-Peking University Strategic Cooperation Project of Fundamental Researchthe New Cornerstone Science Foundationsupport from the Tencent Foundation through the Xplorer Prize.
文摘Polyvinyl chloride(PVC)is one of the most widely used plastic materials worldwide,particularly in long-life applications such as construction materials.However,recycling options for PVC waste remain limited,as conventional methods often degrade material quality or generate environmentally hazardous byproducts.In this study,we demonstrate an efficient process to convert PVC into new polymers with variable aromatic groups,using triethylsilane as the reductant in different solvents.This approach enables the production of polymers analogous to functionalized polyethylene(PE),which are typically challenging to obtain through conventional copolymerization or direct post-modification of C-H bonds in PE.The resulting polymers exhibit tunable thermal and mechanical properties depending on the introduced aromatic groups,which not only enhance the sustainable valorization of PVC waste,but also provide an opportunity for the synthesis of new functionalized polymers.
基金financially supported by the University of Tabriz
文摘Surface of TiO2 nanoparticles was modified with the in situ chemical oxidative polymerization of aniline. Polyaniline modified TiO2 nanoparticles （PANI-TiO2） were characterized with the FT-IR, XRD, SEM and TEM techniques. Results confirmed that PANI was grafted successfully on the surface of TiO2 nanoparticles, therefore agglomeration of nanoparticles decreased dramatically. Polyvinyl chloride nanocomposites filled with 1 wt%-5 wt% of PANI-TiO2 and TiO2 nanoparticles were prepared via the solution blending method. PVC nanocomposites were analyzed with FT-IR, XRD, SEM, TG/DTA, DSC and tensile test techniques. Effect of PANI as surface modifier of nanoparticles was discussed according to the final properties of PVC nanocomposites. Results demonstrated that deposition of PANI on the surface of TiO2 nanoparticles improved the interfacial adhesion between the constituents of nanocomposites, which resulted in better dispersion of nanoparticles in the PVC matrix. Also PVC/PANI-TiO2 nanocomposites showed higher thennal resistance, tensile strength and Young＇s modulus compared to those of unfilled PVC and PVC/TiO2 nanocomposites.
基金financially supported by the Fundamental Research Funds for the Central Universities
文摘To effectively improve the performance and expand the applications of polymers, molecular dynamics(MD) simulations with the COMPASS force field have been applied to predict the miscibility, glass transition temperature(Tg), and mechanical properties of poly(vinyl chloride)/dioctyl phthalate(PVC/DOP) blends. The solubility parameter values obtained are in good agreement with the reference data and the little difference(|Δδ|< 2.0 MPa0.5) between two components indicates that PVC/DOP is a miscible system. Tg is predicted by the slope of the free volume and density versus temperature simulation data based on density and free volume theory which is agree well with the experimental data. In addition, the analyses of mechanical properties results indicate that the values of Young’s modulus(E), bulk modulus(K), and shear modulus(G) decrease with the addition of DOP, demonstrating that the rigidity of material is weakened and the ductility is improved. The mechanical properties can also be effectively improved by increasing the temperature, which may provide a more flexible mixture, with lower E, K, G but an increased ductility.
基金Scientific and Technological Project of Hubei Province(No.2002AA105A01)
文摘Acetanilide, adipic acid and potassium hydrogen phthalate were chosen as nucleating agents of polyvinyl chloride（PVC）, and their effects on PVC crystallization were studied by differential scanning calorimetry, wide angle X-ray diffraction and fourier transform infrared spectroscopy. The experimental results indicate that all of the three additives are compatible with PVC to some extent, but adipic acid＇s compatibility with PVC is less satisfactory. The three additives can improve PVC crystallinity, and acetanilide can decrease PVC glass transition temperature（T）and narrow PVC melting range, while adipic acid and potassium hydrogen phthalate rise T of PVC and widen its melting range. All additives do not affect PVC crystal system and all g samples are in orthorhombic system. All additives can improve （200）, （110）, （210） and （201, 111） planes growing. Moreover, acetanilide and adipic acid can shrink PVC spacings and improve the crystal perfection of PVC, but potassium hydrogen phthalate swells spacings and reduces the perfection of PVC crystal.
基金supported by the National Natural Science Foundation of China (No. U 1507123)the Foundation from Qinghai Science and Technology Department (No. 2014-HZ-817)
文摘A calcium sulfate whisker （CSW） coated with glutaraldehyde crosslinked chitosan （GACS） was prepared to reinforce polyvinyl chloride （PVC） in this study. The results show that the optimum concentration of both chitosan （CS） and glutaraldehyde （GA） is 0.05 wt%. The tensile strength, impact strength, flexural modulus and vicat softening temperature of the PVC composite with 12 wt% of modified CSW are in- creased by 1 Z5%, 40.4%, 0.8% and 3.8% compared with those of the PVC composite with 12 wt~ of unmodified CSW, and by 2.9%, 42.4%, 2Z1% and 6.8% compared with those of pure PVC, respectively. The dynamic mechanical analysis results indicate that the modified CSW/PVC composite exhibits much higher storage modulus and glass transition temperature than those of unmodified CSW/PVC composite and pure PVC. In addition, the modified CSW/PVC composite also demonstrates good thermal properties with a high rapidest decomposition temperature （Trvd） and char residue. The scanning electron microscopy images of tensile-fractured surfaces show that the modified CSW has a strong interfacial adhesion with PVC matrix.
基金Project(50378062) supported by the National Natural Science Foundation of ChinaProject(09JCYBJC08100) supported by the Natural Science Foundation of Tianjin City,China
文摘Thermogravimetric study of medical transfusion tube （MTT） waste containing polyvinyl chloride （PVC） was carried out using the thermogravimetric analyser （TGA） with N2, at different heating rates of 5, 10, 20, 30, 50 ℃/min. The purpose is to obtain pyrolysis characteristics and kinetic parameters of medical waste. The experimental results indicate that the pyrolysis behavior of the MTT sample is in agreement with its main ingredient of PVC, appearing two stair stepping stages. The influence of the additives in MTT on pyrolysis behavior was also revealed, which could improve MTT pyrolysis at lower temperature in the first stage, and cause obvious unsmoothness and asymmetry of the second DTG peak. Four n-order kinetic models of Coats-Redfern, Ozawa, Kissinger and Freeman-carroll were used to get the kinetic parameters. Furthermore, a novel ＂two-step four-reaction model＂ was established to simulate the whole continuous process. The different methods and the kinetic parameters thus obtained were discussed and compared with each other in literatures. The reasons of deviation among kinetic values were tried to be elucidated. The new established model could more satisfactorily describe the pyrolysis process of MTT, being more mechanistic and conveniently serving for the engineering.
基金The project supported by the Natural Science Foundation of Shanxi Province ( No. 2001H18) and the Research Foundation of Shanxi Province for Abroad Returnee (No. 200177)
文摘To enhance the blood compatibility of Polyvinyl Chloride (PVC) film, the film was modified by SO2/O2 gas plasma treatment. The effect of surface sulfonation of PVC treated by various SO2/O2 gas plasma depended on the volume ratio O2/(SO2 +O2). When the volume ratio was 0.5, the effect of sulfonation was the best. Sulfonic acid groups were specifically and efficiently introduced onto the PVC surface, which was proved by X-ray photoelectron spectroscopy (XPS) and Attenuated Total Reflectance Fourier Transfer Infrared (ATR-FTIR) spectroscopy. The surface microstructure of modified PVC film was studied with scanning electron microscopy (SEM). The antithrombogenicity of the samples was determined by the activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT) and plasma recalcification time (PRT) tests and platelet adhesion experiment. The results indicated that the antithrombogenicity of modified PVC was improved remarkably.
基金supported by the Natural Science Foundation Project of Liaoning Provincial Department of Education of China under Grant No.JJL201915404,Zhejiang Provincial Natural Science Foundation of China under Grant No.LQ22E080024 and Zhejiang Province Department of Education Fund of China under Grant No.Y202146776.
文摘The development of recycled aggregate concrete(RAC)provides a new approach to limiting the waste of natural resources.In the present study,the mechanical properties and deformability of RACs were improved by adding basalt fibers(BFs)and using external restraints,such as a fiber-reinforced polymer(FRP)jacket or a PVC pipe.Samples were tested under axial compression.The results showed that RAC(50%replacement of aggregate)containing 0.2%BFs had the best mechanical properties.Using either BFs or PVC reinforcement had a slight effect on the loadbearing capacity and mode of failure.With different levels of BFs,the compressive strengths of the specimens reinforced with 1-layer and 3-layer basalt fiber reinforced polymer(BFRP)increased by 6.7%–10.5%and 16.5%–23.7%,respectively,and the ultimate strains increased by 48.5%–80.7%and 97.1%–141.1%,respectively.The peak stress of the 3-layer BFRP-PVC increased by 42.2%,and the ultimate strain improved by 131.3%,relative to the control.This reinforcement combined the high tensile strength of BFRP,which improved the post-peak behavior,and PVC,which enhanced the structural durability.In addition,to investigate the influence of the various constraints on compressive behavior,the stress-strain response was analyzed.Based on the analysis of experimental results,a peak stress-strain model and an amended ultimate stress-strain model were proposed.The models were verified as well;the result showed that the predictions from calculations are generally consistent with the experimental data(error within 10%).The results of this study provide a theoretical basis and reference for future applications of fiber-reinforced recycled concrete.
基金The work was supported by the National Natural Science Foundation of China(Nos.51804024 and U1960205)the Fundamental Research Funds for the Central Universities(No.FRF-IC-20-09)The authors also thank for the financial support from the State Key Laboratory of Advanced Metallurgy,University of Science and Technology Beijing,China(No.41621002).
文摘In the prevailing incineration processes of municipal solid waste,the presence of polyvinyl chloride(PVC)may cause environmental problems.The energy-intensive ironmaking sector in the iron and steel industry operates at high temperature and under high reduction potential with the function of energy conversion,which can provide a potential path for the collaborative utilization of waste plastics in large quantities and low cost.The gasification of the char formed from PVC when processed in the ironmaking sector is significant for the development of the related technologies.Thus,the gasification experiment of PVC char and traditional carbonaceous materials was performed by thermogravimetric analysis.The results indicated that the gasification ability decreased in the sequence of PVC char>anthracite coal>coke>graphite.Then,kinetics were also analyzed by Coats-Redfern and Doyle approximations.The PVC char showed the best gasification ability with the smallest activation energy,ranging from 87.18 to 117.52 kJ/mol,and the smaller graphitization degree of PVC char compared with other carbonaceous materials should be the main reason for its excellent gasification reactivity.
基金Funded by the National Natural Science Foundation of China(Nos.21173266,21473250)the Fundamental Research Funds for the Central Universities(No.11XNJ021)the Research Funds of Renmin University of China
文摘Chemically functionalized carbon nanotubes were combined with PVC to enhance both toughness and strength by simply mixing long alkyl chain modified multi-wall carbon nanotubes (abbreviated as MWNTs) or Ester-functionalized soluble MWNTs (abbreviated as eMWNTs) with PVC in Tetrahydrofuran (THF)/Cyclohexanone (CH) solution to obtain good dispersity solution. The MWNTs modified with 1-Bromohexadecane can effectively increase the intermolecular force with PVC by hydrogen bond. The obtained nanocomposite has a regular shape with homogeneously dispersed particles. PVC/2 wt% eMWNTs has been proved to possess excellent thermal stability. The intermolecular force between eMWNTs and PVC endows the as-fabricated nanocomposite with enhanced toughness and strength, indicating that our method is promising for wide use in PVC/eMWNTs nanocomposition.
