Non-thermal plasmas under atmospheric pressure are of great interest in polymer surface processing because of their convenience, effectiveness and low cost. In this paper, the treatment of Polyethylene terephthalate (...Non-thermal plasmas under atmospheric pressure are of great interest in polymer surface processing because of their convenience, effectiveness and low cost. In this paper, the treatment of Polyethylene terephthalate (PET) film surface for improving hydrophilicity using the non-thermal plasma generated by atmospheric pressure glow discharge (APGD) in air is conducted. The discharge characteristics of APGD are shown by measurement of their electrical discharge parameters and observation of light-emission phenomena, and the surface properties of PET before and after the APGD treatment are studied using contact angle measurement, x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). It is found that the APGD is homogeneous and stable in the whole gas gap, which differs from the commonly filamentary dielectric barrier discharge (DBD). A short time (several seconds) APGD treatment can modify the surface characteristics of PET film markedly and uniformly. After 10 s APGD treatment, the展开更多
Waste plastics,such as waste polyethylene terephthalate(PET)beverage bottles and waste rubber tyres are major municipal solid wastes,which may lead to various environmental problems if they are not appropriately recyc...Waste plastics,such as waste polyethylene terephthalate(PET)beverage bottles and waste rubber tyres are major municipal solid wastes,which may lead to various environmental problems if they are not appropriately recycled.In this study,the feasibility of collectively recycling the two types of waste into performance-increasing modifiers for asphalt pavements was analyzed.This study aimed to investigate the recycling mechanisms of waste PET-derived additives under the treatment of two amines,triethylenetetramine(TETA)and ethanolamine(EA),and characterize the performances of these additives in modifying rubberized bitumen,a bitumen modified by waste tyre rubber.To this end,infrared spectroscopy and thermal analyses were carried out on the two PET-derived additives(PET–TETA and PET–EA).In addition,infrared spectroscopy,viscosity,dynamic shear rheology,and multiple stress creep recovery tests were performed on the rubberized bitumen samples modified by the two PET-derived additives.We concluded that waste PET can be chemically upcycled into functional additives,which can increase the overall performance of the rubberized bitumen.The recycling method developed in this study not only helps alleviate the landfilling problems of both waste PET plastic and scrap tyres,but also turns these wastes into value-added new materials for building durable pavements.展开更多
In this work,a novel alcohol alkali hydrolysis method was explored for the preparation of terephthalic acid(TPA)from waste polyethylene terephthalate(PET).First,a series of single factor experiments on the depolymeriz...In this work,a novel alcohol alkali hydrolysis method was explored for the preparation of terephthalic acid(TPA)from waste polyethylene terephthalate(PET).First,a series of single factor experiments on the depolymerization rate of waste PET bottles and the yield of TPA were conducted to determine the optimized experimental conditions,in terms of reaction time,reaction temperature,dosage of ethylene glycol and sodium bicarbonate,amount of distilled water and stirring rate.Then IR spectra and elemental analysis were carried out for the characterization of obtained product.Under optimal experimental conditions,over 98%PET can be depolymerized into the target product(TPA)and the purity and yield of TPA are over 97%and 94%,respectively.Both the experimental and analytical results support a feasible process for the preparation of TPA from waste PET.It is expected that this alcohol alkali hydrolysis method can promise an effective way for the sustainable recycling of waste PET.展开更多
Several works have been based on the study of thermal variations in biomass to derive more valuable products such as fuels capable of replacing oil in the event of a crisis or activated carbon used as an adsorbent mat...Several works have been based on the study of thermal variations in biomass to derive more valuable products such as fuels capable of replacing oil in the event of a crisis or activated carbon used as an adsorbent material, widely used in industry for the elimination of unwanted materials, both in liquid and gaseous environments. A study of thermal parameters such as: heating speed, retention time, drying temperature, carbonization temperature, particle size, was carried out with the aim of determining the characteristic factors of the carbonization of Polyethylene terephthalate (PET), sawdust (SC) and sawdust/polyethylene terephthalate (CPS) mixture. The results of the immediate analysis revealed a very low level of ash in PET (0.013%) compared to the level of ash in sawdust (2.9%), as well as a high level of fixed carbon (82.960%), which suggests the presence of mineral oxides and a significant carbon matrix unlike PET, which indicates a very significant organic matrix (essentially made up of organic matter) with the absence of mineral oxides. The study of thermal parameters showed the water loss from Sawdust (SC) and the Sawdust/Polyethylene terephthalate (CPS) mixture, an increase with temperature, unlike that of PET whose variation is essentially zero. Without heat treatment, sawdust alone contains approximately 7% water. The optimal drying temperature for this study is 110˚C for a stay of 24 hours. It appears that the largest mass losses for the PET samples are between 87.19% and 96.05%, followed by that of the mixture, between 47.33% and 64.37%. And the lowest are observed, those of sawdust (from 24.02% to 62.6%). However, here we can say that the influence of the mass is not great, given the slight difference between the losses by temperature. The results of the study of the influence of grain size showed that the differences are insignificant, even if we vary the diameter of the grains from simple to triple. To better minimize physical constraints such as the intragranular diffusibility of the volatile 展开更多
A novel direct method for preparation of dimethyl carbonate and poly（ethylene terephthalate） from ethylene carbonate and dimethyl terephthalate has been demonstrated in the presence of metal acetate catalysts, lithi...A novel direct method for preparation of dimethyl carbonate and poly（ethylene terephthalate） from ethylene carbonate and dimethyl terephthalate has been demonstrated in the presence of metal acetate catalysts, lithium acetate dihydrate showed highest catalytic activity with 47.9% yield of dimethyl carbonate. This method was a green chemical process.展开更多
Stannous-acetylacetonate was prepared efficiently and characterized by ^1H NMR and FT-IR. Its catalytic activity for poly（trimethylene terephthalate） （PTT） synthesis was investigated. By this catalyst, the degree ...Stannous-acetylacetonate was prepared efficiently and characterized by ^1H NMR and FT-IR. Its catalytic activity for poly（trimethylene terephthalate） （PTT） synthesis was investigated. By this catalyst, the degree of esterification of pure terephthalic acid was up to 91.7% after reaction at 260 ℃ for 2 h, while the intrinsic viscosity and content of terminal carboxyl groups of the corresponding PTT polymerized at 260 ℃, 60 Pa for 2 h was 0.8816 dL/g and 17 mol/t,respectively. Stannous-acetylacetonate was more active and promising than tetrabutyl titanate and stannous octoate for PTT synthesis.展开更多
Plastic waste management has emerged as a critical environmental issue due to the exponential increase in plastic consumption worldwide.Polyethylene terephthalate(PET)is extensively used in the production of water bot...Plastic waste management has emerged as a critical environmental issue due to the exponential increase in plastic consumption worldwide.Polyethylene terephthalate(PET)is extensively used in the production of water bottles,which constitutes a significant fraction of the plastic waste.PET recycling is a challenging task due to the lack of efficient and cost-effective depolymerization methods.In this study,we developed a microwave(MW)catalytic depolymerization method for PET recycling using modified zinc oxide loaded with manganese oxide as a cocatalyst.The modified Mn_(3)O_(4)/ZnO catalyst presents high efficiency in depolymerizing PET into its monomers with only 0.4 wt% ratio of the catalyst to PET at 175℃ for 5 min,resulting in 100% conversion of PET and 88% selectivity toward bis-hydroxyethyl terephthalate monomers.It is believed that Mn_(3)O_(4)provides additional Lewis acid sites,promoting the dissociation of glycol from PET,and the MW irradiation plays a crucial role in rapidly heating the ethylene glycol and the catalyst,thereby accelerating the PET depolymerization process.In addition,the heterogeneous nature of the catalyst facilitates its easy separation from the reaction mixture for reuse,simplifying the catalyst recovery process and enabling costeffective and sustainable PET recycling.Thus,this study provides an innovative and sustainable solution for PET recycling,contributing toward the circular economy and mitigating the environmental impact of plastic waste.展开更多
The classical crystallization theories proposed by Avrami, Evans, and Mandelkern wereextended to the nonisothermal situation. The expressions derived from the classical equations canbe expressed in either the differen...The classical crystallization theories proposed by Avrami, Evans, and Mandelkern wereextended to the nonisothermal situation. The expressions derived from the classical equations canbe expressed in either the differential form or the integral form. A method was provided so as toobtain the parameters characterizing the crystallization rate and mechanism from DSC curves withseveral constant heating or cooling rates. The rate constants of crystallization obtained from bothisothermal and nonisothermal curves of poly(ethylene terephthalate)were compared.展开更多
The pyrolysis of poly(ethylene terephthalate)(PET)/poly(butylene terephthalate)(PBT)catalyzed by five alkaline earth metal-based minerals/wastes,namely calcined dolomite,calcite,magnesite,calcium carbide slag(CCS),and...The pyrolysis of poly(ethylene terephthalate)(PET)/poly(butylene terephthalate)(PBT)catalyzed by five alkaline earth metal-based minerals/wastes,namely calcined dolomite,calcite,magnesite,calcium carbide slag(CCS),and ophicalcitum,was conducted by a pyrolyzer-gas chromatography-mass spectrometer(Py-GC-MS)with the objective of recovering benzenes-enriched oil.Compared with magnesium-based catalysts and pure CaO,the calcium-based catalysts with calcium hydroxide as the main component performed better catalytic effect,which could simultaneously promote the hydrolysis of ester products and the decarboxylation of aromatic acids after hydrolysis.For PET,the addition of solid base catalysts at 600℃promoted the complete degradation of aromatic acids and aryl esters,which accounted for 32.6%and 30.7%of the pyrolysis oil,respectively.The content of benzene in oil increased from 8.8%to 31.7%–78.8%.For PBT,the addition of solid base catalysts at 600℃completely decomposed the aromatic acids,which accounted for 67.1%of the pyrolysis oil,and the content of benzene in oil increased from 12.3%to 34.5%–81.0%.During the deoxygenation of polyester pyrolysis products,increasing temperature was more effective for the decomposition/conversion of acetone and tetrahydrofuran,while increasing the alkalinity of the reaction environment contributed to the rapid decrease in acetaldehyde and aryl ketone contents.展开更多
The present work investigated the effect of polyethylene terephthalate (PET) plastic waste on the physico-mechanical and thermal properties of cement-stabilized laterite bricks to see the durability of the modified br...The present work investigated the effect of polyethylene terephthalate (PET) plastic waste on the physico-mechanical and thermal properties of cement-stabilized laterite bricks to see the durability of the modified bricks (CSLB). Samples were formulated by mixing laterite, cement, and different percentages of PET (0%, 3%, 5%, and 7%) by volume. The bricks were produced using the M7MI Hydraform standard interlocking block and kept in the shade for a curing period of 28 days. The addition of 3% to 5% PET to the laterite stabilized with 10% cement results in a decrease in both dry and wet compressive strength, which is determined using the Controlab compression machine. However, the obtained results are in concordance with the standards. The thermal conductivity of CSLB, determined using the box method with the EI700 measurement cell, decreases as the PET content of the mixture increases. A decrease in bulk density from 1.67 to 1.58 g/cm<sup>3</sup> was observed.展开更多
In order to develop a more economical pretreatment method for electroless nickel plating, a dielectric barrier discharge （DBD） plasma at atmospheric pressure was used to improve the hydrophilicity and adhesion of po...In order to develop a more economical pretreatment method for electroless nickel plating, a dielectric barrier discharge （DBD） plasma at atmospheric pressure was used to improve the hydrophilicity and adhesion of poly （ethylene terephthalate） （PET） nonwoven fabric. The properties of the PET nonwoven fabric including its liquid absorptive capacity （WA）, aging behavior, surface chemical composition, morphology of the surface, adhesion strength, surface electrical resistivity and electromagnetic interference （EMI）- shielding effectiveness （SE） were studied. The liquid absorptive capacity （WA） increased due to the incorporation of oxygen-containing and nitrogen-containing functional groups on the surface of PET nonwoven fabric after DBD airplasma treatment. The surface morphology of the nonwoven fibers became rougher after plasma treatment. Therefore, the surface was more prone to absorb tin sensitizer and palladium catalyst to form an active layer for the deposition of electroless nickel. SEM and X-ray diffraction （XRD） measurements indicated that a uniform coating of nickel was formed on the PET nonwoven fabric. The average EMI-SE of Ni-plating of PET nonwoven fabric maintained a relatively stable value （38.2 dB to 37.3 dB） in a frequency range of 50 MHz to 1500 MHz. It is concluded that DBD is feasible for pretreatment of nonwoven fabric for electroless nickel plating to prepare functional material with good EMI-SE properties.展开更多
Plastic waste puts a huge burden on the ecosystem due to the current lack of mature recycling technology.Poly(ethylene terephthalate)(PET)is one of the most produced plastics in the world.Enzymatic decomposition holds...Plastic waste puts a huge burden on the ecosystem due to the current lack of mature recycling technology.Poly(ethylene terephthalate)(PET)is one of the most produced plastics in the world.Enzymatic decomposition holds the promise of recovering monomers from PET plastic,and the monomers can be used to regenerate new PET products.However,there are still limitations in the activity and thermal stability of the existing PET hydrolases.The recent study by Lu et al.introduced a novel PET hydrolase via machine learning-aided engineering.The obtained PET hydrolase showed excellent activity and thermal stability in the hydrolysis of PET and is capable of directly degrading large amounts of postconsumer PET products.This approach provides an effective method for recycling PET waste and is expected to improve the current state of plastic pollution worldwide.展开更多
Polyethylene terephthalate glycol,PETG,is a miscible,transparent thermoplastic known to have strong tensile properties,high ductility,as well as resistance to heat and chemical insults.PETG may be manufactured in seve...Polyethylene terephthalate glycol,PETG,is a miscible,transparent thermoplastic known to have strong tensile properties,high ductility,as well as resistance to heat and chemical insults.PETG may be manufactured in several ways,most notably 3D printing modalities.As such,PETG has emerged as a viable biomaterial for a variety of medical applications such as tissue engineering,dentistry,optometry,vascular health,cardiology,orthopedics,neurology,gynecology,and surgery.PETG also serves a valuable role in biomedical research and engineering by offering improvements in cell studies,drug carriers,and anti-bacterial measures.Further medical research and innovation utilizing PETG will better characterize its value as an inexpensive and versatile biomaterial.展开更多
文摘Non-thermal plasmas under atmospheric pressure are of great interest in polymer surface processing because of their convenience, effectiveness and low cost. In this paper, the treatment of Polyethylene terephthalate (PET) film surface for improving hydrophilicity using the non-thermal plasma generated by atmospheric pressure glow discharge (APGD) in air is conducted. The discharge characteristics of APGD are shown by measurement of their electrical discharge parameters and observation of light-emission phenomena, and the surface properties of PET before and after the APGD treatment are studied using contact angle measurement, x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). It is found that the APGD is homogeneous and stable in the whole gas gap, which differs from the commonly filamentary dielectric barrier discharge (DBD). A short time (several seconds) APGD treatment can modify the surface characteristics of PET film markedly and uniformly. After 10 s APGD treatment, the
基金support from the Hong Kong Environment and Conservation Fund through ECF Project(84/2017)Science and Technology Project of Henan Provincial Department of Transportation(2020J6).
文摘Waste plastics,such as waste polyethylene terephthalate(PET)beverage bottles and waste rubber tyres are major municipal solid wastes,which may lead to various environmental problems if they are not appropriately recycled.In this study,the feasibility of collectively recycling the two types of waste into performance-increasing modifiers for asphalt pavements was analyzed.This study aimed to investigate the recycling mechanisms of waste PET-derived additives under the treatment of two amines,triethylenetetramine(TETA)and ethanolamine(EA),and characterize the performances of these additives in modifying rubberized bitumen,a bitumen modified by waste tyre rubber.To this end,infrared spectroscopy and thermal analyses were carried out on the two PET-derived additives(PET–TETA and PET–EA).In addition,infrared spectroscopy,viscosity,dynamic shear rheology,and multiple stress creep recovery tests were performed on the rubberized bitumen samples modified by the two PET-derived additives.We concluded that waste PET can be chemically upcycled into functional additives,which can increase the overall performance of the rubberized bitumen.The recycling method developed in this study not only helps alleviate the landfilling problems of both waste PET plastic and scrap tyres,but also turns these wastes into value-added new materials for building durable pavements.
基金Project(2016TP1007)supported by the Hunan Provincial Science and Technology Plan,China
文摘In this work,a novel alcohol alkali hydrolysis method was explored for the preparation of terephthalic acid(TPA)from waste polyethylene terephthalate(PET).First,a series of single factor experiments on the depolymerization rate of waste PET bottles and the yield of TPA were conducted to determine the optimized experimental conditions,in terms of reaction time,reaction temperature,dosage of ethylene glycol and sodium bicarbonate,amount of distilled water and stirring rate.Then IR spectra and elemental analysis were carried out for the characterization of obtained product.Under optimal experimental conditions,over 98%PET can be depolymerized into the target product(TPA)and the purity and yield of TPA are over 97%and 94%,respectively.Both the experimental and analytical results support a feasible process for the preparation of TPA from waste PET.It is expected that this alcohol alkali hydrolysis method can promise an effective way for the sustainable recycling of waste PET.
文摘Several works have been based on the study of thermal variations in biomass to derive more valuable products such as fuels capable of replacing oil in the event of a crisis or activated carbon used as an adsorbent material, widely used in industry for the elimination of unwanted materials, both in liquid and gaseous environments. A study of thermal parameters such as: heating speed, retention time, drying temperature, carbonization temperature, particle size, was carried out with the aim of determining the characteristic factors of the carbonization of Polyethylene terephthalate (PET), sawdust (SC) and sawdust/polyethylene terephthalate (CPS) mixture. The results of the immediate analysis revealed a very low level of ash in PET (0.013%) compared to the level of ash in sawdust (2.9%), as well as a high level of fixed carbon (82.960%), which suggests the presence of mineral oxides and a significant carbon matrix unlike PET, which indicates a very significant organic matrix (essentially made up of organic matter) with the absence of mineral oxides. The study of thermal parameters showed the water loss from Sawdust (SC) and the Sawdust/Polyethylene terephthalate (CPS) mixture, an increase with temperature, unlike that of PET whose variation is essentially zero. Without heat treatment, sawdust alone contains approximately 7% water. The optimal drying temperature for this study is 110˚C for a stay of 24 hours. It appears that the largest mass losses for the PET samples are between 87.19% and 96.05%, followed by that of the mixture, between 47.33% and 64.37%. And the lowest are observed, those of sawdust (from 24.02% to 62.6%). However, here we can say that the influence of the mass is not great, given the slight difference between the losses by temperature. The results of the study of the influence of grain size showed that the differences are insignificant, even if we vary the diameter of the grains from simple to triple. To better minimize physical constraints such as the intragranular diffusibility of the volatile
文摘A novel direct method for preparation of dimethyl carbonate and poly（ethylene terephthalate） from ethylene carbonate and dimethyl terephthalate has been demonstrated in the presence of metal acetate catalysts, lithium acetate dihydrate showed highest catalytic activity with 47.9% yield of dimethyl carbonate. This method was a green chemical process.
文摘Stannous-acetylacetonate was prepared efficiently and characterized by ^1H NMR and FT-IR. Its catalytic activity for poly（trimethylene terephthalate） （PTT） synthesis was investigated. By this catalyst, the degree of esterification of pure terephthalic acid was up to 91.7% after reaction at 260 ℃ for 2 h, while the intrinsic viscosity and content of terminal carboxyl groups of the corresponding PTT polymerized at 260 ℃, 60 Pa for 2 h was 0.8816 dL/g and 17 mol/t,respectively. Stannous-acetylacetonate was more active and promising than tetrabutyl titanate and stannous octoate for PTT synthesis.
基金UK EPSRC project(EP/S018204/2)Royal Society Leverhulme Trust Senior Research Fellowship(SRF\R1\21000153).
文摘Plastic waste management has emerged as a critical environmental issue due to the exponential increase in plastic consumption worldwide.Polyethylene terephthalate(PET)is extensively used in the production of water bottles,which constitutes a significant fraction of the plastic waste.PET recycling is a challenging task due to the lack of efficient and cost-effective depolymerization methods.In this study,we developed a microwave(MW)catalytic depolymerization method for PET recycling using modified zinc oxide loaded with manganese oxide as a cocatalyst.The modified Mn_(3)O_(4)/ZnO catalyst presents high efficiency in depolymerizing PET into its monomers with only 0.4 wt% ratio of the catalyst to PET at 175℃ for 5 min,resulting in 100% conversion of PET and 88% selectivity toward bis-hydroxyethyl terephthalate monomers.It is believed that Mn_(3)O_(4)provides additional Lewis acid sites,promoting the dissociation of glycol from PET,and the MW irradiation plays a crucial role in rapidly heating the ethylene glycol and the catalyst,thereby accelerating the PET depolymerization process.In addition,the heterogeneous nature of the catalyst facilitates its easy separation from the reaction mixture for reuse,simplifying the catalyst recovery process and enabling costeffective and sustainable PET recycling.Thus,this study provides an innovative and sustainable solution for PET recycling,contributing toward the circular economy and mitigating the environmental impact of plastic waste.
基金This work was supported by the Tianjin Youth Science Foundation for the 21th Century,Tianjin,China.
文摘The classical crystallization theories proposed by Avrami, Evans, and Mandelkern wereextended to the nonisothermal situation. The expressions derived from the classical equations canbe expressed in either the differential form or the integral form. A method was provided so as toobtain the parameters characterizing the crystallization rate and mechanism from DSC curves withseveral constant heating or cooling rates. The rate constants of crystallization obtained from bothisothermal and nonisothermal curves of poly(ethylene terephthalate)were compared.
基金would like to gratefully acknowledge the National Key Research and Development Program(No.2018YFC1901300)the Key Research and Development Program of Zhejiang Province(No.2020C03084).
文摘The pyrolysis of poly(ethylene terephthalate)(PET)/poly(butylene terephthalate)(PBT)catalyzed by five alkaline earth metal-based minerals/wastes,namely calcined dolomite,calcite,magnesite,calcium carbide slag(CCS),and ophicalcitum,was conducted by a pyrolyzer-gas chromatography-mass spectrometer(Py-GC-MS)with the objective of recovering benzenes-enriched oil.Compared with magnesium-based catalysts and pure CaO,the calcium-based catalysts with calcium hydroxide as the main component performed better catalytic effect,which could simultaneously promote the hydrolysis of ester products and the decarboxylation of aromatic acids after hydrolysis.For PET,the addition of solid base catalysts at 600℃promoted the complete degradation of aromatic acids and aryl esters,which accounted for 32.6%and 30.7%of the pyrolysis oil,respectively.The content of benzene in oil increased from 8.8%to 31.7%–78.8%.For PBT,the addition of solid base catalysts at 600℃completely decomposed the aromatic acids,which accounted for 67.1%of the pyrolysis oil,and the content of benzene in oil increased from 12.3%to 34.5%–81.0%.During the deoxygenation of polyester pyrolysis products,increasing temperature was more effective for the decomposition/conversion of acetone and tetrahydrofuran,while increasing the alkalinity of the reaction environment contributed to the rapid decrease in acetaldehyde and aryl ketone contents.
文摘The present work investigated the effect of polyethylene terephthalate (PET) plastic waste on the physico-mechanical and thermal properties of cement-stabilized laterite bricks to see the durability of the modified bricks (CSLB). Samples were formulated by mixing laterite, cement, and different percentages of PET (0%, 3%, 5%, and 7%) by volume. The bricks were produced using the M7MI Hydraform standard interlocking block and kept in the shade for a curing period of 28 days. The addition of 3% to 5% PET to the laterite stabilized with 10% cement results in a decrease in both dry and wet compressive strength, which is determined using the Controlab compression machine. However, the obtained results are in concordance with the standards. The thermal conductivity of CSLB, determined using the box method with the EI700 measurement cell, decreases as the PET content of the mixture increases. A decrease in bulk density from 1.67 to 1.58 g/cm<sup>3</sup> was observed.
基金supported by National Natural Science Foundation of China (No.50833003)
文摘In order to develop a more economical pretreatment method for electroless nickel plating, a dielectric barrier discharge （DBD） plasma at atmospheric pressure was used to improve the hydrophilicity and adhesion of poly （ethylene terephthalate） （PET） nonwoven fabric. The properties of the PET nonwoven fabric including its liquid absorptive capacity （WA）, aging behavior, surface chemical composition, morphology of the surface, adhesion strength, surface electrical resistivity and electromagnetic interference （EMI）- shielding effectiveness （SE） were studied. The liquid absorptive capacity （WA） increased due to the incorporation of oxygen-containing and nitrogen-containing functional groups on the surface of PET nonwoven fabric after DBD airplasma treatment. The surface morphology of the nonwoven fibers became rougher after plasma treatment. Therefore, the surface was more prone to absorb tin sensitizer and palladium catalyst to form an active layer for the deposition of electroless nickel. SEM and X-ray diffraction （XRD） measurements indicated that a uniform coating of nickel was formed on the PET nonwoven fabric. The average EMI-SE of Ni-plating of PET nonwoven fabric maintained a relatively stable value （38.2 dB to 37.3 dB） in a frequency range of 50 MHz to 1500 MHz. It is concluded that DBD is feasible for pretreatment of nonwoven fabric for electroless nickel plating to prepare functional material with good EMI-SE properties.
基金support from the Beijing Municipal Natural Science Foundation(2222012)the National Natural Science Foundation of China(Grant No.52070116)+1 种基金the Key-Area Research and Development Program of Guangdong Province(2020B1111380001)the Tsinghua University-Shanxi Clean Energy Research Institute Innovation Project Seed Fund is gratefully acknowledged.
文摘Plastic waste puts a huge burden on the ecosystem due to the current lack of mature recycling technology.Poly(ethylene terephthalate)(PET)is one of the most produced plastics in the world.Enzymatic decomposition holds the promise of recovering monomers from PET plastic,and the monomers can be used to regenerate new PET products.However,there are still limitations in the activity and thermal stability of the existing PET hydrolases.The recent study by Lu et al.introduced a novel PET hydrolase via machine learning-aided engineering.The obtained PET hydrolase showed excellent activity and thermal stability in the hydrolysis of PET and is capable of directly degrading large amounts of postconsumer PET products.This approach provides an effective method for recycling PET waste and is expected to improve the current state of plastic pollution worldwide.
文摘Polyethylene terephthalate glycol,PETG,is a miscible,transparent thermoplastic known to have strong tensile properties,high ductility,as well as resistance to heat and chemical insults.PETG may be manufactured in several ways,most notably 3D printing modalities.As such,PETG has emerged as a viable biomaterial for a variety of medical applications such as tissue engineering,dentistry,optometry,vascular health,cardiology,orthopedics,neurology,gynecology,and surgery.PETG also serves a valuable role in biomedical research and engineering by offering improvements in cell studies,drug carriers,and anti-bacterial measures.Further medical research and innovation utilizing PETG will better characterize its value as an inexpensive and versatile biomaterial.
