Aim To determine the effect of silane grafted polypropylene on the property of different filler/polypropylene composites. Methods Polypropylene (PP) composites filled with talc(Ta), baryta sulfate and calcium carbonat...Aim To determine the effect of silane grafted polypropylene on the property of different filler/polypropylene composites. Methods Polypropylene (PP) composites filled with talc(Ta), baryta sulfate and calcium carbonate coupled with silane grafted polypropylene (PP-g-Si) were made, their mechanical properties and thermal properties were investigated, respectively. Results As compared with the non-coupled composites, the mechanical properties of PP/Ta/PP-g-Si composites were improved to some extent, though the values of tensile modulus and the strain at peak were decreased. But for PP/BaSO4 and PP/CaCO3 composites, the values of their mechanical properties varied slightly or even decreased with increasing PP-g-Si content within the experimental component. Meanwhile, PP-g-Si also affected the melting and crystallization behavior of PP in the composites. Conclusion PP-g-Si offers compatibilization in PP/Ta composites, but offers no-compatibilization in PP/BaSO4 and PP/CaCO3 composites within the extent of the present range of PP-g-Si, which shows that PP-g-Si can be used as the macromolecular coupling agent of PP and Ta composite.展开更多
The interface reaction between ultraviolet irradiated polypropylene (UV-PP) and an amino silane coupling agent, γ-aminopropyltrimethoxysilane (γ-APS) adsorbed on glass fibers has been investigated by means of the co...The interface reaction between ultraviolet irradiated polypropylene (UV-PP) and an amino silane coupling agent, γ-aminopropyltrimethoxysilane (γ-APS) adsorbed on glass fibers has been investigated by means of the combining use of solvent extraction and FTIR as well as XPS. First, polypropylene (PP) physisorbed on the glass fibers surface was removed by the solvent extraction in order to minimize the effect of the PP siginal in FTIR and XPS analyses. Second, the remaining glass fibers after solvent extraction were analyzed by FTIR and XPS. The results show that the absorption bands of PP still exist in the FTIR spectrum and two new bands of N1s at 399. 1eV and 401.6eV appear in the XPS spectrum for the composite with UV-PP and γ-APS treated glass fibers. Thus, the interface reaction between the UV-PP and γ-APS has been monitored directly. In addition, it may be concluded that OH and COOH groups of UV-PP form chemical bonds with NH2 group of γ-APS , respectively.展开更多
Rapid corrosion of magnesium alloys in the physiological environment limits their use as orthopedic implant materials.Therefore,the silane film modified with nano-hydroxyapatite(n HA)was prepared on the surface of AZ3...Rapid corrosion of magnesium alloys in the physiological environment limits their use as orthopedic implant materials.Therefore,the silane film modified with nano-hydroxyapatite(n HA)was prepared on the surface of AZ31 magnesium alloy to improve its corrosion resistance.The silane films are continuous,uniform,and adherent well to the Mg substrate,and the modification of the film by n HA increased the thickness from~1.92 to~3.25μm.Compared to the bare substrate,the corrosion current density of the sample with the silane film modified with n HA decreases by three orders of magnitude from 9.23×10^(-5)to 2.779×10^(-8)A/cm~2.According to the immersion tests,it is found that the synergistic effect of sub-film corrosion and blistering is the dominant mode of film failure.During the immersion of less than 72 h,the modification by n HA improves the corrosion resistance by delaying the sub-film corrosion and blistering of the film.展开更多
Polyolefins with intrinsic antimicrobial properties have attracted significant attention.In this study,various ion-functionalized polyolefins were successfully constructed by incorporating iodine-containing comonomers...Polyolefins with intrinsic antimicrobial properties have attracted significant attention.In this study,various ion-functionalized polyolefins were successfully constructed by incorporating iodine-containing comonomers into a polypropylene backbone,followed by post-functionalization strategies that utilized the conversion reactions of pre-introduced iodine groups.The introduction of ionic groups induced notable changes in both the thermal properties and the melt rheological behavior of the material.The dual crosslinking mechanism based on ionic interactions and polypropylene crystallization significantly enhanced the mechanical strength of the material.In addition,imidazolium-based ionomers exhibit highly effective antimicrobial properties against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus.Specifically,the P5-CCl_(3)CO_(2)^(−)sample achieved a sterilization rate of 99.99%against both bacteria and maintained a high bactericidal efficacy of above 90%,even after continuous supplementation with fresh bacterial solutions for 15 days.Consequently,this polypropylene-based ionomer,which combines excellent mechanical strength with outstanding antimicrobial performance,demonstrates substantial application potential in children’s toys,food packaging,and medicine.展开更多
To promote the application of green recycled construction materials in civil engineering,this study presents a statistical damage constitutive model for polypropylene fiber recycled fine aggregate concrete(PRFAC),base...To promote the application of green recycled construction materials in civil engineering,this study presents a statistical damage constitutive model for polypropylene fiber recycled fine aggregate concrete(PRFAC),based on the strain equivalence principle and the assumption that microelement strength follows a Weibull statistical distribution.The proposed model incorporates the Drucker-Prager failure criterion.By examining the influence of Weibull distribution parameters m and S_(0)on the stress-strain response,empirical relationships were established between the fine aggregate replacement ratio and the distribution parameters.This enabled the derivation of a theoretical stress-strain curve accounting for variable recycled fine aggragate(RFA)replacement ratios.The experimental results show that the proposed model exhibits high agreement with measured data and effectively captures the increased brittleness of PRFAC with higher RFA replacement ratios.Moreover,increasing the replacement rate accelerates internal crack propagation,reduces deformability and toughness,and significantly hastens the accumulation of internal damage in PRFAC.展开更多
This article describes the results of an investigation on the influence of loading silane treated sugar cane bagasse (SB) on the morphology and properties of recycled polypropylene (rPP). The samples are prepared thro...This article describes the results of an investigation on the influence of loading silane treated sugar cane bagasse (SB) on the morphology and properties of recycled polypropylene (rPP). The samples are prepared through melt extrusion followed by injection moulding. The Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) results show that SB-rPP composites have a fairly strong interfacial interaction and a change in crystallization for the highest containing SB composite, however, some fibre pull-outs are observed as the SB content is increased. The interaction influences the thermal and mechanical properties of the samples in a complex way. There are strong indications of a stronger interfacial interaction on the highest containing SB composite, which is supposedly accountable for the increased crystallinity and melting temperature.展开更多
A visible-light-enabled method for the synthesis ofα-azidoketones has been developed via oxo-azidation of alkenyl silanes with trimethylsilylazide and molecular oxygen under mild conditions.The reaction could be carr...A visible-light-enabled method for the synthesis ofα-azidoketones has been developed via oxo-azidation of alkenyl silanes with trimethylsilylazide and molecular oxygen under mild conditions.The reaction could be carried out in gram scale.Various radical sources,including trifluoromethyl radical,thiocyanate radical,bromide radical,chlorine radical could partici-pate effectively instead of azide radical in the reaction.展开更多
Leachate sludge,a byproduct of municipal solid waste leachate treated through biochemical processes,is characterized by high water content(761.1%)and significant organic matter content(71.2%).Cement that is commonly u...Leachate sludge,a byproduct of municipal solid waste leachate treated through biochemical processes,is characterized by high water content(761.1%)and significant organic matter content(71.2%).Cement that is commonly used for solidifying leachate sludge has shown limited effectiveness.To address this issue,an alkali-activated ground-granulated blast-furnace slag(GGBS)geopolymer blended with polypropylene fibers was developed to solidify leachate sludge.Moreover,unconfined compressive strength(UCS),immersion,as well as X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),and scanning electron microscope(SEM)tests were conducted to investigate the solidification effect and mechanism of the GGBS-based geopolymer and fibers on leachate sludge.The results showed that:the 28-d UCS of the solidified sludge with 20%and 30%GGBS is 0.35 MPa and 1.85 MPa,and decreases to 0.18 MPa and 1.13 MPa,respectively,after soaked in water for 28 d.Notably,the UCS of the solidified sludge with 30%GGBS satisfied the strength requirement of roadbed materials.Polypropylene fibers significantly enhanced the strength,ductility and water stability of the solidified sludge,with an optimal fiber content of 0.3%.Alkali-activated GGBS geopolymer generated three-dimensional,cross-linked geopolymeric gels within the solidified sludge,cementing sludge particles and filling intergranular pores to form a stable cementitious structure,thereby achieving effective solidification.Furthermore,incorporating polypropylene fibers improved the bonding and anchoring effect between fiber and solidified sludge,constrained lateral deformation of the solidified sludge,restricted crack propagation,and enhanced engineering performance of the solidified leachate sludge.展开更多
To compare the suitable working conditions of polypropylene(PP)and polycaprolactam(PA6)materials in actual use in automobiles,the effects of different temperature aging and different reagents on the mechanical propert...To compare the suitable working conditions of polypropylene(PP)and polycaprolactam(PA6)materials in actual use in automobiles,the effects of different temperature aging and different reagents on the mechanical properties of the two materials,such as tensile,bending,compression,and impact were studied.The results indicate that the short⁃term low⁃temperature environment had no much effect on the mechanical properties of PP and PA6.After long⁃term thermal aging at 80℃,the strength of PP and PA6 increased while their toughness decreased.After short⁃term thermal aging at 120℃,PP strength decreases and toughness increases,while PA6 strength increases and toughness decreases.The soaking of glass water and car shampoo had no much effect on the mechanical properties of PP,but had a significant impact on the mechanical properties of PA6.With the increase of soaking time,the strength of PA6 significantly decreases and the toughness significantly increases.The soaking of 95#gasoline had no much effect on the mechanical properties of PA6,but has a significant impact on the mechanical properties of PP.After 720 h of soaking,the retention rates of the tensile strength,bending strength,and compressive strength of PP were all less than 80%,while the retention rate of the impact strength of the cantilever beam was 160.4%.展开更多
An environmentally friendly waterborne polyurethane(CWPU)emulsion was developed via a dual modification strategy by combining both the silane coupling agent KH-602 with renewable castor oil(CO)as a sustainable substit...An environmentally friendly waterborne polyurethane(CWPU)emulsion was developed via a dual modification strategy by combining both the silane coupling agent KH-602 with renewable castor oil(CO)as a sustainable substitute for petroleum-based polyols.The resulting materials were thoroughly characterized using Fourier-transform infrared spectroscopy(FTIR),thermogravimetric analysis(TGA),and differential scanning calorimetry(DSC).Furthermore,the influence of KH-602 content on the material properties was systematically investigated.The experimental results reveal that the incorporation of KH-602 significantly improves the thermal stability of the composite coating.As the KH-602 content increases,the tensile strength exhibits a gradual enhancement,while the elongation at break displays an initial increase followed by a subsequent decline.At an optimal KH-602 content of 3%,the coating demonstrates a balanced performance,achieving a tensile strength of 14.19 MPa and an elongation at break of 731.12%.These results suggest that the dual modification approach enhances mechanical and thermal properties while maintaining water resistance,making it suitable for sustainable coating applications.展开更多
A novel eco-friendly charring agent(L-OH)was successfully synthesized by combining pentaerythritol(PER)with lignin through a simple two-step reaction.The structure of L-OH was characterized using Fourier transform inf...A novel eco-friendly charring agent(L-OH)was successfully synthesized by combining pentaerythritol(PER)with lignin through a simple two-step reaction.The structure of L-OH was characterized using Fourier transform infrared(FTIR),X-ray diffraction(XRD),scanning electron microscopy(SEM)and EDS.In addition,L-OH was introduced into polypropylene(PP)together with melamine(MEL)and ammonium polyphosphate(APP)as an intumescent flame retardant(IFRR).The flame retardancy of PP/IFRR composites were investigated using limited oxygen index(LOI),UL-94,thermogravimetric analysis(TGA)and cone calorimeter(CC)test.The experimental results indicate that the PP/IFRR composites pass the V-0 grade of the UL-94 test when the addition amount of IFRR is no less than 20%,and the LOI value of the composite reaches 32.2%at 30%IFRR addition.The peak heat release rate(PHRR)and peak smoke production rate(PSPR)of the composite decrease by 72.8%and 70.4%compared with pure PP,respectively.The flame retardancy mechanism was investigated by TGA,TG-FTIR and residual carbon analysis.These analyses indicate that L-OH can form a more continuous and dense carbon layer during the combustion process,which is the main factor contributing to the improved flame retardancy of PP.展开更多
The present study presents an assessment of the interrelations between long-chain branching,specific nucleation,and end-use properties of polypropylene blends:blends of linear polypropylene(L-PP)and long-chain branche...The present study presents an assessment of the interrelations between long-chain branching,specific nucleation,and end-use properties of polypropylene blends:blends of linear polypropylene(L-PP)and long-chain branched polypropylene(LCB-PP)modified by a specificβ-nucleating agent(NA).Specimens with various LCB-PP compositions with and without NA were prepared under complex flow fields by injection molding.Wide-angle X-ray scattering was employed to capture the X-ray patterns of both the skin and core of the specimens,determining the overall crystallinity and amounts of individual polymorphs.The increasing content of LCB-PP andγ-phase,at the same time,in the blends is reflected in both increasing crystallinity and improved mechanical properties,namely,yield stress and Young’s modulus.On the other hand,the composition of the blends had no significant effect on the impact strength,except for nucleated L-PP.It has been demonstrated that adding a relatively small amount of LCB-PP is sufficient to modify the mechanical properties of linear polypropylene.Even a very small amount of LCB-PP in the L-PP suppressed the effectiveness of NA.展开更多
Polypropylene(PP)has low inherent susceptibility to common industrial lasers,which poses a significant challenge for laser-based marking.To improve the laser sensitivity of PP,molybdenum disulfide grafted with polysty...Polypropylene(PP)has low inherent susceptibility to common industrial lasers,which poses a significant challenge for laser-based marking.To improve the laser sensitivity of PP,molybdenum disulfide grafted with polystyrene(MoS_(2)-g-PS)was synthesized via in-situ free radical polymerization and used as a laser-sensitive filler for PP composites prepared by melt blending.The composites were then marked with a 1064 nm semiconductor laser,producing clear and legible patterns.The marked surfaces were characterized using scanning electron microscopy(SEM),transmission electron microscopy(TEM),colorimetry,Raman spectroscopy,and thermogravimetric analysis(TGA).The results demonstrate that the PP/MoS_(2)-g-PS composites exhibit significantly improved laser markability compared to both pure PP and PP/MoS_(2) composites,yielding superior marking quality.When the MoS_(2)-g-PS content was 0.02 wt%and the laser current intensity was 11 A,a clearly recognizable QR code pattern was obtained with high resolution and legibility.The mechanism of laser-induced marking on the PP/MoS_(2)-g-PS composites involves efficient absorption of near-infrared(NIR)laser energy and photothermal conversion by the MoS_(2) core,while the surrounding PS layer carbonizes upon laser irradiation.The synergistic effect between MoS_(2) and PS effectively enhance the laser marking performance of PP.展开更多
A comparative study of products of thermal and thermocatalytic cracking of polypropylene(PP) in the presence of potassium polytitanate(PPT) synthesized by treatment of TiO_(2)(rutile) powder with molten mixture of KOH...A comparative study of products of thermal and thermocatalytic cracking of polypropylene(PP) in the presence of potassium polytitanate(PPT) synthesized by treatment of TiO_(2)(rutile) powder with molten mixture of KOH and KNO_(3) taken in a weight ratio of 30∶30∶40 has been carried out.It was shown that the studied type of PPT powder exhibits catalytic properties in the reaction of thermal decomposition of PP,compared to the effect of commercial zeolite catalyst CBV-780 traditionally used for this purpose.Based on the analysis performed,the differences in the mechanism of catalytic action of PPT and the zeolite were considered.The reasons for the observed differences in the composition of PP cracking products and in the rate of coke formation on the surface of studied catalysts were analyzed.Considering the obtained results,it has been proposed that the CBV-780 catalyst promoted more intensive production of the gaseous hydrocarbons compared to PPT,due to higher specific surface area(internal surface) accessible for relatively light and small-sized hydrocarbon products of cracking.However,intensive coke formation on the outer surface of the microporous zeolite contributes to the blocking of transport channels and the rapid loss of catalytic action.At the same time,PPT,which initially has a smaller specific surface area,retains its catalytic activity significantly longer due to slit-shaped flat pores and higher transport accessibility of the inner surface.展开更多
This study reports the fabrication of polypropylene(PP)-based microfiber webs(<1µm) using a hybrid melt electrospinning/blown process with the aim of establishing a scalable and solvent-free platform for advan...This study reports the fabrication of polypropylene(PP)-based microfiber webs(<1µm) using a hybrid melt electrospinning/blown process with the aim of establishing a scalable and solvent-free platform for advanced lithium-ion battery separators. The primary objective was to address the inherent limitations of conventional melt electrospinning particularly the difficulty of achieving fiber thinning due to the high viscosity of polymer melts by incorporating auxiliary hot air flow and reducing the nozzle diameter from 1.0mm to 0.3mm. This modified configuration enables enhanced jet elongation and fiber diameter control under processing conditions relevant to industrial applications. The effects of nozzle temperature, hot air temperature, and applied voltage on fiber formation and jet behavior were systematically examined using highspeed charge-coupled device(CCD) imaging techniques. The results demonstrated that increasing both the hot air temperature and applied voltage significantly improved fiber thinning and uniformity, yielding an average fiber diameter of approximately 0.86µm without evidence of thermal degradation. In contrast, elevated nozzle temperatures, while enhancing melt flowability, resulted in increased discharge rates and hindered fiber refinement when applied alone. These findings identify hot-air temperature as the most robust and controllable parameter for producing submicron fibers while maintaining the polymer integrity. Although the present study primarily focuses on morphological optimization and jet dynamics, future research will investigate the functional performance of fabricated microfiber webs as battery separators. Overall, the proposed hybrid process offers a technically feasible and environmentally sustainable route for the continuous production of fine PP-based fibers tailored for high-performance energy-storage applications.展开更多
Polypropylene(PP)has a relatively low melt strength due to its linear structure,which seriously limits its supercritical CO_(2)foaming performance.Introducing long-chain branches(LCBs)via grafting can significantly en...Polypropylene(PP)has a relatively low melt strength due to its linear structure,which seriously limits its supercritical CO_(2)foaming performance.Introducing long-chain branches(LCBs)via grafting can significantly enhance its melt strength.However,the relationship between the LCB level of high melt strength polypropylene(HMSPP)and its foaming behavior remains unclear.In this study,a series of HMSPP with different LCB levels was prepared using vinyl polydimethylsiloxane(VS)of varying viscosities as grafting monomers to investigate this relationship.Rheological analysis showed that the increase in viscosity of VS led to higher LCB levels in HMSPP.The melt strength of HMSPP increases with the increase of LCB levels,reaching up to 0.62 N,which is 13 times higher than that of the raw material.Supercritical CO_(2)foaming results revealed that the expansion ratio of HMSPP first increased and then decreased with the increase of melt strength,reaching a maximum of 39.4 times.Combining experiments with simulations,the influence of LCB levels on the dissolution and diffusion behavior of CO_(2)in HMSPP was clarified.This study deepens the understanding of the relationship between LCB and the foaming behavior of HMSPP,providing valuable insights for designing HMSPP with optimized foaming properties.展开更多
This study focuses on the electrical properties and microstructure of polypropylene(PP)-based blends used for cable insulation in nuclear power plants(NPPs).The PP-based blend,comprising isotactic PP and propylene-bas...This study focuses on the electrical properties and microstructure of polypropylene(PP)-based blends used for cable insulation in nuclear power plants(NPPs).The PP-based blend,comprising isotactic PP and propylene-based elastomer(PBE)at concentrations ranging from 0 to 50 wt%,underwent a melt blending process and subsequent cobalt-60 gamma-ray irradiation with doses ranging from 0 to 250 kGy.Electrical conductivity,trap distribution,and alternating(AC)breakdown strength were chosen to assess the insulation performance.These results indicate that the addition of PBE significantly improves the electrical properties of PP under irradiation.For PP,the electrical conductivity increased with irradiation,whereas the trap depth and breakdown strength decreased sharply.Conversely,for the blend,these changes initially exhibit opposite trends.When the irradiation was increased to 250 kGy,the AC breakdown strength of the blend improved by more than 21%compared to that of PP.The physical and chemical structures of the samples were investigated to explore the improvement mechanisms.The results offer insights into the design of new cable-insulation materials suitable for NPPs.展开更多
Geological samples often contain significant amounts of iron,which,although not typically the target element,can substantially interfere with the analysis of other elements of interest.To mitigate these interferences,...Geological samples often contain significant amounts of iron,which,although not typically the target element,can substantially interfere with the analysis of other elements of interest.To mitigate these interferences,amidoximebased radiation grafted adsorbents have been identified as effective for iron removal.In this study,an amidoximefunctionalized,radiation-grafted adsorbent synthesized from polypropylene waste(PPw-g-AO-10)was employed to remove iron from leached geological samples.The adsorption process was systematically optimized by investigating the effects of pH,contact time,adsorbent dosage,and initial ferric ion concentration.Under optimal conditions-pH1.4,a contact time of 90 min,and an initial ferric ion concentration of 4500 mg/L-the adsorbent exhibited a maximum iron adsorption capacity of 269.02 mg/g.After optimizing the critical adsorption parameters,the adsorbent was applied to the leached geological samples,achieving a 91%removal of the iron content.The adsorbent was regenerated through two consecutive cycles using 0.2 N HNO_(3),achieving a regeneration efficiency of 65%.These findings confirm the efficacy of the synthesized PPw-g-AO-10 as a cost-effective and eco-friendly adsorbent for successfully removing iron from leached geological matrices while maintaining a reasonable degree of reusability.展开更多
Fiber reinforcement significantly enhances the strength,toughness,and durability of concrete by reducing the propagation of microcracks in the concrete matrix.With the rising demand for high-performance concrete(HPC),...Fiber reinforcement significantly enhances the strength,toughness,and durability of concrete by reducing the propagation of microcracks in the concrete matrix.With the rising demand for high-performance concrete(HPC),this study investigates the mechanical properties of HPC with varying proportions of polypropylene(PP)and steel(ST)fibers.Supplementary cementitious materials(SCMs)toward partial replacement of ordinary Portland cement(OPC)were incorporated to prepare HPC mixes as a ternary composite system using Fly Ash(FA),Silica Fume(SF),and Ground Granulated Blast Furnace Slag(GGBS).Each HPC mix comprised two SCMs,accounting for 20%of the mass fraction of the OPC binder.The study encompassed fiber percentages ranging from 0 to 0.075%PP and 0 to 2%ST,incorporating them into the HPC mixes with gradual increases of 0.025%for PP and 0.5%for ST fiber by mass fraction.All HPC mixes were tested for mechanical properties using compressive and split tensile strength tests.The influence of SCMs on HPC was studied using X-ray diffraction(XRD)for microstructural analyses.It was found that the compressive and split tensile strengths of HPC increased up to an optimal fiber percentage and then decreased.A comparison of the test results of high-performance fiber-reinforced concrete with those of plain HPC revealed significant improvements in compressive and splitting tensile strengths by 26.59%and 57.74%,respectively.Also,the XRD analysis revealed that the composition of the SCMs in HPC was a significant and effective solution for the mechanical properties of the concrete.展开更多
The new energy vehicle body composed of multi-metals requires a synchronous chemical conversion coating to exhibit excellent corrosion resistance.Herein,we prepared a titanium/zirconium/water-based oligomeric epoxy si...The new energy vehicle body composed of multi-metals requires a synchronous chemical conversion coating to exhibit excellent corrosion resistance.Herein,we prepared a titanium/zirconium/water-based oligomeric epoxy silane composite chemical conversion coating on multi-metals,and conducted an investigation into its electrochemical behavior and micro-zone structural characteristics upon immersion in a 3.5%NaCl solution.The electrochemical results combined with characterization results revealed that the corrosion evolution characteristics of the composite coatings could be categorized into three stages of mild corrosion,synergistic protection,and substrate damage.Besides,Si-OH groups interact with Me-OH at the defect on the multi-metal surface to form an organic monolayer coating.This organic monolayer coating,in conjunction with the synergistic inorganic conversion layer comprising Al_(2)O_(3),TiO_(2),2H_(2)O,ZrO_(2),2H_(2)O,effectively cooperates with the corrosion products to hinder the erosion by the corrosive medium and suppresses the progression of the anodic reaction.展开更多
文摘Aim To determine the effect of silane grafted polypropylene on the property of different filler/polypropylene composites. Methods Polypropylene (PP) composites filled with talc(Ta), baryta sulfate and calcium carbonate coupled with silane grafted polypropylene (PP-g-Si) were made, their mechanical properties and thermal properties were investigated, respectively. Results As compared with the non-coupled composites, the mechanical properties of PP/Ta/PP-g-Si composites were improved to some extent, though the values of tensile modulus and the strain at peak were decreased. But for PP/BaSO4 and PP/CaCO3 composites, the values of their mechanical properties varied slightly or even decreased with increasing PP-g-Si content within the experimental component. Meanwhile, PP-g-Si also affected the melting and crystallization behavior of PP in the composites. Conclusion PP-g-Si offers compatibilization in PP/Ta composites, but offers no-compatibilization in PP/BaSO4 and PP/CaCO3 composites within the extent of the present range of PP-g-Si, which shows that PP-g-Si can be used as the macromolecular coupling agent of PP and Ta composite.
基金Jointly Funded by the National Natural Science Foundation of China (No. 19972049) and the Natural Science Foundation of Hubei Province (No. 99J073).
文摘The interface reaction between ultraviolet irradiated polypropylene (UV-PP) and an amino silane coupling agent, γ-aminopropyltrimethoxysilane (γ-APS) adsorbed on glass fibers has been investigated by means of the combining use of solvent extraction and FTIR as well as XPS. First, polypropylene (PP) physisorbed on the glass fibers surface was removed by the solvent extraction in order to minimize the effect of the PP siginal in FTIR and XPS analyses. Second, the remaining glass fibers after solvent extraction were analyzed by FTIR and XPS. The results show that the absorption bands of PP still exist in the FTIR spectrum and two new bands of N1s at 399. 1eV and 401.6eV appear in the XPS spectrum for the composite with UV-PP and γ-APS treated glass fibers. Thus, the interface reaction between the UV-PP and γ-APS has been monitored directly. In addition, it may be concluded that OH and COOH groups of UV-PP form chemical bonds with NH2 group of γ-APS , respectively.
基金supported by the Key Research and Development Program of Shandong Province(No.2021ZLGX01)Shanghai Kindly Medical Instrument Co.,Ltd。
文摘Rapid corrosion of magnesium alloys in the physiological environment limits their use as orthopedic implant materials.Therefore,the silane film modified with nano-hydroxyapatite(n HA)was prepared on the surface of AZ31 magnesium alloy to improve its corrosion resistance.The silane films are continuous,uniform,and adherent well to the Mg substrate,and the modification of the film by n HA increased the thickness from~1.92 to~3.25μm.Compared to the bare substrate,the corrosion current density of the sample with the silane film modified with n HA decreases by three orders of magnitude from 9.23×10^(-5)to 2.779×10^(-8)A/cm~2.According to the immersion tests,it is found that the synergistic effect of sub-film corrosion and blistering is the dominant mode of film failure.During the immersion of less than 72 h,the modification by n HA improves the corrosion resistance by delaying the sub-film corrosion and blistering of the film.
基金financially supported by the National Natural Science Foundation of China(Nos.52130307 and 52121002).
文摘Polyolefins with intrinsic antimicrobial properties have attracted significant attention.In this study,various ion-functionalized polyolefins were successfully constructed by incorporating iodine-containing comonomers into a polypropylene backbone,followed by post-functionalization strategies that utilized the conversion reactions of pre-introduced iodine groups.The introduction of ionic groups induced notable changes in both the thermal properties and the melt rheological behavior of the material.The dual crosslinking mechanism based on ionic interactions and polypropylene crystallization significantly enhanced the mechanical strength of the material.In addition,imidazolium-based ionomers exhibit highly effective antimicrobial properties against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus.Specifically,the P5-CCl_(3)CO_(2)^(−)sample achieved a sterilization rate of 99.99%against both bacteria and maintained a high bactericidal efficacy of above 90%,even after continuous supplementation with fresh bacterial solutions for 15 days.Consequently,this polypropylene-based ionomer,which combines excellent mechanical strength with outstanding antimicrobial performance,demonstrates substantial application potential in children’s toys,food packaging,and medicine.
基金The National Natural Science Foundation of China(No.52168022).
文摘To promote the application of green recycled construction materials in civil engineering,this study presents a statistical damage constitutive model for polypropylene fiber recycled fine aggregate concrete(PRFAC),based on the strain equivalence principle and the assumption that microelement strength follows a Weibull statistical distribution.The proposed model incorporates the Drucker-Prager failure criterion.By examining the influence of Weibull distribution parameters m and S_(0)on the stress-strain response,empirical relationships were established between the fine aggregate replacement ratio and the distribution parameters.This enabled the derivation of a theoretical stress-strain curve accounting for variable recycled fine aggragate(RFA)replacement ratios.The experimental results show that the proposed model exhibits high agreement with measured data and effectively captures the increased brittleness of PRFAC with higher RFA replacement ratios.Moreover,increasing the replacement rate accelerates internal crack propagation,reduces deformability and toughness,and significantly hastens the accumulation of internal damage in PRFAC.
文摘This article describes the results of an investigation on the influence of loading silane treated sugar cane bagasse (SB) on the morphology and properties of recycled polypropylene (rPP). The samples are prepared through melt extrusion followed by injection moulding. The Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) results show that SB-rPP composites have a fairly strong interfacial interaction and a change in crystallization for the highest containing SB composite, however, some fibre pull-outs are observed as the SB content is increased. The interaction influences the thermal and mechanical properties of the samples in a complex way. There are strong indications of a stronger interfacial interaction on the highest containing SB composite, which is supposedly accountable for the increased crystallinity and melting temperature.
文摘A visible-light-enabled method for the synthesis ofα-azidoketones has been developed via oxo-azidation of alkenyl silanes with trimethylsilylazide and molecular oxygen under mild conditions.The reaction could be carried out in gram scale.Various radical sources,including trifluoromethyl radical,thiocyanate radical,bromide radical,chlorine radical could partici-pate effectively instead of azide radical in the reaction.
基金financially supported by the National Natural Science Foundation of China(Grant No.52078142).
文摘Leachate sludge,a byproduct of municipal solid waste leachate treated through biochemical processes,is characterized by high water content(761.1%)and significant organic matter content(71.2%).Cement that is commonly used for solidifying leachate sludge has shown limited effectiveness.To address this issue,an alkali-activated ground-granulated blast-furnace slag(GGBS)geopolymer blended with polypropylene fibers was developed to solidify leachate sludge.Moreover,unconfined compressive strength(UCS),immersion,as well as X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),and scanning electron microscope(SEM)tests were conducted to investigate the solidification effect and mechanism of the GGBS-based geopolymer and fibers on leachate sludge.The results showed that:the 28-d UCS of the solidified sludge with 20%and 30%GGBS is 0.35 MPa and 1.85 MPa,and decreases to 0.18 MPa and 1.13 MPa,respectively,after soaked in water for 28 d.Notably,the UCS of the solidified sludge with 30%GGBS satisfied the strength requirement of roadbed materials.Polypropylene fibers significantly enhanced the strength,ductility and water stability of the solidified sludge,with an optimal fiber content of 0.3%.Alkali-activated GGBS geopolymer generated three-dimensional,cross-linked geopolymeric gels within the solidified sludge,cementing sludge particles and filling intergranular pores to form a stable cementitious structure,thereby achieving effective solidification.Furthermore,incorporating polypropylene fibers improved the bonding and anchoring effect between fiber and solidified sludge,constrained lateral deformation of the solidified sludge,restricted crack propagation,and enhanced engineering performance of the solidified leachate sludge.
文摘To compare the suitable working conditions of polypropylene(PP)and polycaprolactam(PA6)materials in actual use in automobiles,the effects of different temperature aging and different reagents on the mechanical properties of the two materials,such as tensile,bending,compression,and impact were studied.The results indicate that the short⁃term low⁃temperature environment had no much effect on the mechanical properties of PP and PA6.After long⁃term thermal aging at 80℃,the strength of PP and PA6 increased while their toughness decreased.After short⁃term thermal aging at 120℃,PP strength decreases and toughness increases,while PA6 strength increases and toughness decreases.The soaking of glass water and car shampoo had no much effect on the mechanical properties of PP,but had a significant impact on the mechanical properties of PA6.With the increase of soaking time,the strength of PA6 significantly decreases and the toughness significantly increases.The soaking of 95#gasoline had no much effect on the mechanical properties of PA6,but has a significant impact on the mechanical properties of PP.After 720 h of soaking,the retention rates of the tensile strength,bending strength,and compressive strength of PP were all less than 80%,while the retention rate of the impact strength of the cantilever beam was 160.4%.
基金Funded by the Basic Scientific Research of Liaoning Provincial Department of Education(No.LJ212410153030)。
文摘An environmentally friendly waterborne polyurethane(CWPU)emulsion was developed via a dual modification strategy by combining both the silane coupling agent KH-602 with renewable castor oil(CO)as a sustainable substitute for petroleum-based polyols.The resulting materials were thoroughly characterized using Fourier-transform infrared spectroscopy(FTIR),thermogravimetric analysis(TGA),and differential scanning calorimetry(DSC).Furthermore,the influence of KH-602 content on the material properties was systematically investigated.The experimental results reveal that the incorporation of KH-602 significantly improves the thermal stability of the composite coating.As the KH-602 content increases,the tensile strength exhibits a gradual enhancement,while the elongation at break displays an initial increase followed by a subsequent decline.At an optimal KH-602 content of 3%,the coating demonstrates a balanced performance,achieving a tensile strength of 14.19 MPa and an elongation at break of 731.12%.These results suggest that the dual modification approach enhances mechanical and thermal properties while maintaining water resistance,making it suitable for sustainable coating applications.
基金the equipment support of Sharing Platform of Scientific Equipments,Ministry of Education's Research Center for Comprehensive Utilization and Clean Process Engineering of Phosphrous Resources,Sichuan University。
文摘A novel eco-friendly charring agent(L-OH)was successfully synthesized by combining pentaerythritol(PER)with lignin through a simple two-step reaction.The structure of L-OH was characterized using Fourier transform infrared(FTIR),X-ray diffraction(XRD),scanning electron microscopy(SEM)and EDS.In addition,L-OH was introduced into polypropylene(PP)together with melamine(MEL)and ammonium polyphosphate(APP)as an intumescent flame retardant(IFRR).The flame retardancy of PP/IFRR composites were investigated using limited oxygen index(LOI),UL-94,thermogravimetric analysis(TGA)and cone calorimeter(CC)test.The experimental results indicate that the PP/IFRR composites pass the V-0 grade of the UL-94 test when the addition amount of IFRR is no less than 20%,and the LOI value of the composite reaches 32.2%at 30%IFRR addition.The peak heat release rate(PHRR)and peak smoke production rate(PSPR)of the composite decrease by 72.8%and 70.4%compared with pure PP,respectively.The flame retardancy mechanism was investigated by TGA,TG-FTIR and residual carbon analysis.These analyses indicate that L-OH can form a more continuous and dense carbon layer during the combustion process,which is the main factor contributing to the improved flame retardancy of PP.
文摘The present study presents an assessment of the interrelations between long-chain branching,specific nucleation,and end-use properties of polypropylene blends:blends of linear polypropylene(L-PP)and long-chain branched polypropylene(LCB-PP)modified by a specificβ-nucleating agent(NA).Specimens with various LCB-PP compositions with and without NA were prepared under complex flow fields by injection molding.Wide-angle X-ray scattering was employed to capture the X-ray patterns of both the skin and core of the specimens,determining the overall crystallinity and amounts of individual polymorphs.The increasing content of LCB-PP andγ-phase,at the same time,in the blends is reflected in both increasing crystallinity and improved mechanical properties,namely,yield stress and Young’s modulus.On the other hand,the composition of the blends had no significant effect on the impact strength,except for nucleated L-PP.It has been demonstrated that adding a relatively small amount of LCB-PP is sufficient to modify the mechanical properties of linear polypropylene.Even a very small amount of LCB-PP in the L-PP suppressed the effectiveness of NA.
文摘Polypropylene(PP)has low inherent susceptibility to common industrial lasers,which poses a significant challenge for laser-based marking.To improve the laser sensitivity of PP,molybdenum disulfide grafted with polystyrene(MoS_(2)-g-PS)was synthesized via in-situ free radical polymerization and used as a laser-sensitive filler for PP composites prepared by melt blending.The composites were then marked with a 1064 nm semiconductor laser,producing clear and legible patterns.The marked surfaces were characterized using scanning electron microscopy(SEM),transmission electron microscopy(TEM),colorimetry,Raman spectroscopy,and thermogravimetric analysis(TGA).The results demonstrate that the PP/MoS_(2)-g-PS composites exhibit significantly improved laser markability compared to both pure PP and PP/MoS_(2) composites,yielding superior marking quality.When the MoS_(2)-g-PS content was 0.02 wt%and the laser current intensity was 11 A,a clearly recognizable QR code pattern was obtained with high resolution and legibility.The mechanism of laser-induced marking on the PP/MoS_(2)-g-PS composites involves efficient absorption of near-infrared(NIR)laser energy and photothermal conversion by the MoS_(2) core,while the surrounding PS layer carbonizes upon laser irradiation.The synergistic effect between MoS_(2) and PS effectively enhance the laser marking performance of PP.
文摘A comparative study of products of thermal and thermocatalytic cracking of polypropylene(PP) in the presence of potassium polytitanate(PPT) synthesized by treatment of TiO_(2)(rutile) powder with molten mixture of KOH and KNO_(3) taken in a weight ratio of 30∶30∶40 has been carried out.It was shown that the studied type of PPT powder exhibits catalytic properties in the reaction of thermal decomposition of PP,compared to the effect of commercial zeolite catalyst CBV-780 traditionally used for this purpose.Based on the analysis performed,the differences in the mechanism of catalytic action of PPT and the zeolite were considered.The reasons for the observed differences in the composition of PP cracking products and in the rate of coke formation on the surface of studied catalysts were analyzed.Considering the obtained results,it has been proposed that the CBV-780 catalyst promoted more intensive production of the gaseous hydrocarbons compared to PPT,due to higher specific surface area(internal surface) accessible for relatively light and small-sized hydrocarbon products of cracking.However,intensive coke formation on the outer surface of the microporous zeolite contributes to the blocking of transport channels and the rapid loss of catalytic action.At the same time,PPT,which initially has a smaller specific surface area,retains its catalytic activity significantly longer due to slit-shaped flat pores and higher transport accessibility of the inner surface.
基金financially supported by the Technology Innovation Program(or Industrial Strategic Technology Development Program)(No.20017666)funded by the Ministry of Trade,Industry,and Energy(MOTIE,Korea)。
文摘This study reports the fabrication of polypropylene(PP)-based microfiber webs(<1µm) using a hybrid melt electrospinning/blown process with the aim of establishing a scalable and solvent-free platform for advanced lithium-ion battery separators. The primary objective was to address the inherent limitations of conventional melt electrospinning particularly the difficulty of achieving fiber thinning due to the high viscosity of polymer melts by incorporating auxiliary hot air flow and reducing the nozzle diameter from 1.0mm to 0.3mm. This modified configuration enables enhanced jet elongation and fiber diameter control under processing conditions relevant to industrial applications. The effects of nozzle temperature, hot air temperature, and applied voltage on fiber formation and jet behavior were systematically examined using highspeed charge-coupled device(CCD) imaging techniques. The results demonstrated that increasing both the hot air temperature and applied voltage significantly improved fiber thinning and uniformity, yielding an average fiber diameter of approximately 0.86µm without evidence of thermal degradation. In contrast, elevated nozzle temperatures, while enhancing melt flowability, resulted in increased discharge rates and hindered fiber refinement when applied alone. These findings identify hot-air temperature as the most robust and controllable parameter for producing submicron fibers while maintaining the polymer integrity. Although the present study primarily focuses on morphological optimization and jet dynamics, future research will investigate the functional performance of fabricated microfiber webs as battery separators. Overall, the proposed hybrid process offers a technically feasible and environmentally sustainable route for the continuous production of fine PP-based fibers tailored for high-performance energy-storage applications.
基金the financial support of this work by the National Natural Science Foundation of China(Grant 21878089).
文摘Polypropylene(PP)has a relatively low melt strength due to its linear structure,which seriously limits its supercritical CO_(2)foaming performance.Introducing long-chain branches(LCBs)via grafting can significantly enhance its melt strength.However,the relationship between the LCB level of high melt strength polypropylene(HMSPP)and its foaming behavior remains unclear.In this study,a series of HMSPP with different LCB levels was prepared using vinyl polydimethylsiloxane(VS)of varying viscosities as grafting monomers to investigate this relationship.Rheological analysis showed that the increase in viscosity of VS led to higher LCB levels in HMSPP.The melt strength of HMSPP increases with the increase of LCB levels,reaching up to 0.62 N,which is 13 times higher than that of the raw material.Supercritical CO_(2)foaming results revealed that the expansion ratio of HMSPP first increased and then decreased with the increase of melt strength,reaching a maximum of 39.4 times.Combining experiments with simulations,the influence of LCB levels on the dissolution and diffusion behavior of CO_(2)in HMSPP was clarified.This study deepens the understanding of the relationship between LCB and the foaming behavior of HMSPP,providing valuable insights for designing HMSPP with optimized foaming properties.
基金supported by the National Natural Science Foundation of China(No.52077151)the State Key Laboratory of Electrical Insulation and Power Equipment(No.EIPE23208)the Key Laboratory of Engineering Dielectrics and Its Application,Ministry of Education(No.KFM202203).
文摘This study focuses on the electrical properties and microstructure of polypropylene(PP)-based blends used for cable insulation in nuclear power plants(NPPs).The PP-based blend,comprising isotactic PP and propylene-based elastomer(PBE)at concentrations ranging from 0 to 50 wt%,underwent a melt blending process and subsequent cobalt-60 gamma-ray irradiation with doses ranging from 0 to 250 kGy.Electrical conductivity,trap distribution,and alternating(AC)breakdown strength were chosen to assess the insulation performance.These results indicate that the addition of PBE significantly improves the electrical properties of PP under irradiation.For PP,the electrical conductivity increased with irradiation,whereas the trap depth and breakdown strength decreased sharply.Conversely,for the blend,these changes initially exhibit opposite trends.When the irradiation was increased to 250 kGy,the AC breakdown strength of the blend improved by more than 21%compared to that of PP.The physical and chemical structures of the samples were investigated to explore the improvement mechanisms.The results offer insights into the design of new cable-insulation materials suitable for NPPs.
文摘Geological samples often contain significant amounts of iron,which,although not typically the target element,can substantially interfere with the analysis of other elements of interest.To mitigate these interferences,amidoximebased radiation grafted adsorbents have been identified as effective for iron removal.In this study,an amidoximefunctionalized,radiation-grafted adsorbent synthesized from polypropylene waste(PPw-g-AO-10)was employed to remove iron from leached geological samples.The adsorption process was systematically optimized by investigating the effects of pH,contact time,adsorbent dosage,and initial ferric ion concentration.Under optimal conditions-pH1.4,a contact time of 90 min,and an initial ferric ion concentration of 4500 mg/L-the adsorbent exhibited a maximum iron adsorption capacity of 269.02 mg/g.After optimizing the critical adsorption parameters,the adsorbent was applied to the leached geological samples,achieving a 91%removal of the iron content.The adsorbent was regenerated through two consecutive cycles using 0.2 N HNO_(3),achieving a regeneration efficiency of 65%.These findings confirm the efficacy of the synthesized PPw-g-AO-10 as a cost-effective and eco-friendly adsorbent for successfully removing iron from leached geological matrices while maintaining a reasonable degree of reusability.
基金financed by the Science and Engineering Research Board,India,in Project No.EEQ/2023/000130CSIR-India in Project No.MLP072002.
文摘Fiber reinforcement significantly enhances the strength,toughness,and durability of concrete by reducing the propagation of microcracks in the concrete matrix.With the rising demand for high-performance concrete(HPC),this study investigates the mechanical properties of HPC with varying proportions of polypropylene(PP)and steel(ST)fibers.Supplementary cementitious materials(SCMs)toward partial replacement of ordinary Portland cement(OPC)were incorporated to prepare HPC mixes as a ternary composite system using Fly Ash(FA),Silica Fume(SF),and Ground Granulated Blast Furnace Slag(GGBS).Each HPC mix comprised two SCMs,accounting for 20%of the mass fraction of the OPC binder.The study encompassed fiber percentages ranging from 0 to 0.075%PP and 0 to 2%ST,incorporating them into the HPC mixes with gradual increases of 0.025%for PP and 0.5%for ST fiber by mass fraction.All HPC mixes were tested for mechanical properties using compressive and split tensile strength tests.The influence of SCMs on HPC was studied using X-ray diffraction(XRD)for microstructural analyses.It was found that the compressive and split tensile strengths of HPC increased up to an optimal fiber percentage and then decreased.A comparison of the test results of high-performance fiber-reinforced concrete with those of plain HPC revealed significant improvements in compressive and splitting tensile strengths by 26.59%and 57.74%,respectively.Also,the XRD analysis revealed that the composition of the SCMs in HPC was a significant and effective solution for the mechanical properties of the concrete.
基金financially supported by the National Natural Science Foundation of China(No.52075391).
文摘The new energy vehicle body composed of multi-metals requires a synchronous chemical conversion coating to exhibit excellent corrosion resistance.Herein,we prepared a titanium/zirconium/water-based oligomeric epoxy silane composite chemical conversion coating on multi-metals,and conducted an investigation into its electrochemical behavior and micro-zone structural characteristics upon immersion in a 3.5%NaCl solution.The electrochemical results combined with characterization results revealed that the corrosion evolution characteristics of the composite coatings could be categorized into three stages of mild corrosion,synergistic protection,and substrate damage.Besides,Si-OH groups interact with Me-OH at the defect on the multi-metal surface to form an organic monolayer coating.This organic monolayer coating,in conjunction with the synergistic inorganic conversion layer comprising Al_(2)O_(3),TiO_(2),2H_(2)O,ZrO_(2),2H_(2)O,effectively cooperates with the corrosion products to hinder the erosion by the corrosive medium and suppresses the progression of the anodic reaction.
