研究了采用次磷酸钠作还原剂在涤纶织物上化学镀铜。分别采用X射线衍射(XRD)、扫描电镜(SEM)和能谱议(EDAX)分析化学镀铜层的晶体结构、表面形貌和镀层成分。分别用四探针法(ASTM F390)和双轴传输线法(ASTM D 4935-99)测量导电涤纶织物...研究了采用次磷酸钠作还原剂在涤纶织物上化学镀铜。分别采用X射线衍射(XRD)、扫描电镜(SEM)和能谱议(EDAX)分析化学镀铜层的晶体结构、表面形貌和镀层成分。分别用四探针法(ASTM F390)和双轴传输线法(ASTM D 4935-99)测量导电涤纶织物的表面电阻和电磁屏蔽效能。化学镀铜溶液的成分和操作条件对化学镀铜的沉积速度、镀层成分、结构和表面形貌具有重大的影响。化学镀铜的沉积速度随着温度、pH值和镍离子浓度的升高而加快,而且沉速度过快会导致镀层疏松。镍离子浓度的增加还导致镀层镍含量的增加从而使表面电阻明显增大。加入适量的亚铁氰化钾可以降低沉积速度,改善镀层结构和表面形貌,降低织物表面电阻。当Ni2+和K4Fe(CN)6浓度分别为0.0038mol/L和2×10-6时,可以获得最佳的化学镀铜层;当织物上铜镀层的重量为40g/m2时,在100MHz^20GHz频率范围内电磁屏蔽效能均可达到85dB以上。展开更多
Rational design and controlled fabrication of efficient and cost-effective electrodes for the oxygen evolution reaction （OER） are critical for addressing the unpre- cedented energy crisis. Nickel-iron layered double...Rational design and controlled fabrication of efficient and cost-effective electrodes for the oxygen evolution reaction （OER） are critical for addressing the unpre- cedented energy crisis. Nickel-iron layered double hydroxides （NiFe-LDHs） with specific interlayer anions （i.e. phosphate, phosphite, and hypophosphite） were fabricated by a co-predpitation method and investigated as oxygen evolution electrocatalysts. Intercalation of the phosphorus oxoanion enhanced the OER activity in an alkaline solution; the optimal performance （i.e., a low onset potential of 215 mV, a small Tafel slope of 37.7 mV/dec, and stable electrochemical behavior） was achieved with the hypophosphite-intercalated NiFe-LDH catalyst, demonstrating dramatic enhancement over the traditional carbonate-intercalated NiFe-LDH in terms of activity and durability. This enhanced performance is attributed to the interaction between the intercalated phosphorous oxoanions and the edge-sharing MO6 （M = Ni, Fe） layers, which modifies the surface electronic structure of the Ni sites. This concept should be inspiring for the design of more effective LDH-based oxygen evolution electrocatalvsts.展开更多
The effects of aluminum hypophosphite（AHP） as a synergistic agent on the flame retardancy and thermal degradation behavior of intumescent flame retardant polypropylene composites（PP/IFR） containing ammonium polyph...The effects of aluminum hypophosphite（AHP） as a synergistic agent on the flame retardancy and thermal degradation behavior of intumescent flame retardant polypropylene composites（PP/IFR） containing ammonium polyphosphate（APP） and triazine charring-foaming agent（CFA） were investigated by limiting oxygen index（LOI）, UL-94 measurement, thermogravimetric analysis（TGA）, cone calorimeter test（CONE）, scanning electron microscopy（SEM） and X-ray photoelectron spectroscopy（XPS）. It was found that the combination of IFR with AHP exhibited an evident synergistic effect and enhanced the flame retardant efficiency for PP matrix. The specimens with the thickness of 0.8 mm can pass UL-94 V-0 rating and the LOI value reaches 33.5% based on the total loading of flame retardant of 24 wt%, and the optimum mass fraction of AHP/IFR is 1：6. The TGA data revealed that AHP could change the degradation behavior of IFR and PP/IFR system, enhance the thermal stability of the IFR and PP/IFR systems at high temperatures and promote the char residue formation. The CONE results revealed that IFR/AHP blends can efficiently reduce the combustion parameters of PP, such as heat release rate（HRR）, total heat release（THR）, smoke production rate（SPR） and so on. The morphological structures of char residue demonstrated that AHP is of benefit to the formation of a more compact and homogeneous char layer on the materials surface during burning. The analysis of XPS indicates that AHP may promote the formation of sufficient char on the materials surface and improve the flame retardant properties.展开更多
Aluminum hypophosphite （AP） was used to prepare flame-retarded thermoplastic polyurethane （FR-TPU） composites, and their flame retardancy, thermal degradation and mechanical properties were investigated by limitin...Aluminum hypophosphite （AP） was used to prepare flame-retarded thermoplastic polyurethane （FR-TPU） composites, and their flame retardancy, thermal degradation and mechanical properties were investigated by limiting oxygen index （LOI）, vertical burning test （UL-94）, thermogravimetric analysis （TGA）, cone calorimeter （CC） test, Fourier transform infrared （FTIR） spectroscopy, scanning electron microscopy （SEM） and tensile test. TPU containing 30 wt% of AP could reach a V-0 rating in the UL-94 test, and its LOI value was 30.2. TGA tests revealed that AP enhanced the formation of residual chars at high temperatures, and slightly affected the thermal stability of TPU at high temperatures. The combustion tests indicated that AP affected the burning behavior of TPU. The peak of heat release rate （PHRR）, total heat release （THR） and mass loss rate （MLR） greatly reduced due to the incorporation of AP. The tensile test results showed that both the tensile strength and the elongation at break slightly decreased with the addition of AP. The digital photos and SEM micrographs vitrified that AP facilitated the formation of more compact intumescent char layer. Based on these results mentioned above, the flame-retarding mechanism of AP was discussed. Both the self-charring during the decomposing process of AP and its facilitation to the charring of TPU led to the great improvement in the flame retardancy of TPU.展开更多
Both citrate and hypophosphite in aqueous solution were degraded by advanced oxidation processes （Fe^2＋/H2O2, UV/Fe^2＋/H2O2, and electrolysis/Fe^2＋/H2O2） in this study. Comparison of these techniques in oxidation...Both citrate and hypophosphite in aqueous solution were degraded by advanced oxidation processes （Fe^2＋/H2O2, UV/Fe^2＋/H2O2, and electrolysis/Fe^2＋/H2O2） in this study. Comparison of these techniques in oxidation efficiency was undertaken. It was found that Fenton process could not completely degrade citrate in the presence of hypophosphite since it caused a series inhibition. Therefore, UV light （photo-Fenton） or electron current （electro-Fenton） was applied to improve the degradation efficiency of the Fenton process. Results showed that both photo-Fenton and electro-Fenton processes could overcome the inhibition of hypophosphite, especially the electro-Fenton.展开更多
Doped phosphide is promising in earthabundant element based catalysts for hydrogen evolution reaction(HER). Here we employ ammonium hypophosphite(NH4H2PO2) to synthesize a novel parallel doped catalyst,nitrogen doped ...Doped phosphide is promising in earthabundant element based catalysts for hydrogen evolution reaction(HER). Here we employ ammonium hypophosphite(NH4H2PO2) to synthesize a novel parallel doped catalyst,nitrogen doped molybdenum phosphide nanoparticles(NPs)supported on nitrogen doped carbon nanotubes(N-MoP/N-CNTs). The NH4H2PO2 as a bifunctional agent severs as both phosphidation agent and nitrogen source, which makes the synthetic route simple and efficient. The as-obtained parallel doped N-MoP/N-CNTs show an overpotential of 103±5 mV at 10 mA cm-2, which is 140 mV lower than that of MoP NPs. The enhanced HER performance is attributed to the electronic effect by doped MoP and CNTs supports. This work provides a facile route to synthesize doped phosphides for the potential applications in hydrogen energy.展开更多
Aluminum hypophosphite microspheres(AHP) were synthesized by hydrothermal method using NaH2PO2·H2O and AlCl3·6H2O as raw materials, and then the AHP microspheres were polymerized by surface polymerization of...Aluminum hypophosphite microspheres(AHP) were synthesized by hydrothermal method using NaH2PO2·H2O and AlCl3·6H2O as raw materials, and then the AHP microspheres were polymerized by surface polymerization of micro-nanospheres with cyclic cross-linked poly(cyclotriphosphazene-co-4,4'-sulfonyldiphenol)(PZS). A new organic-inorganic poly(phosphonitrile)-modified aluminum hypophosphite microspheres(PZS-AHP) were synthesized by encapsulation and applied to flame retardant thermoplastic polyurethane(TPU). The microstructure and chemical composition of the PZS-AHP microsphere were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray spectroscopy. The thermal stability of PZS-AHP microsphere was explored with thermogravimetric analysis. Thermogravimetric data indicate that the PZS-AHP microspheres have excellent thermal stability. The thermal and flame-retarding properties of the TPU composites were evaluated by thermogravimetric(TG), limited oxygen index tests(LOI), and cone calorimeter test(CCT). The TPU composite achieved vertical burning(UL-94) V-0 grade and LOI value reached 29.2% when 10 wt% PZS-AHP was incorporated. Compared with those of pure TPU, the peak heat release rate(pHRR) and total heat release(THR) of TPU/10%PZS-AHP decreased by 82.2% and 42.5%, respectively. The results of CCT indicated that PZS-AHP microsphere could improve the flame retardancy of TPU composites.展开更多
文摘研究了采用次磷酸钠作还原剂在涤纶织物上化学镀铜。分别采用X射线衍射(XRD)、扫描电镜(SEM)和能谱议(EDAX)分析化学镀铜层的晶体结构、表面形貌和镀层成分。分别用四探针法(ASTM F390)和双轴传输线法(ASTM D 4935-99)测量导电涤纶织物的表面电阻和电磁屏蔽效能。化学镀铜溶液的成分和操作条件对化学镀铜的沉积速度、镀层成分、结构和表面形貌具有重大的影响。化学镀铜的沉积速度随着温度、pH值和镍离子浓度的升高而加快,而且沉速度过快会导致镀层疏松。镍离子浓度的增加还导致镀层镍含量的增加从而使表面电阻明显增大。加入适量的亚铁氰化钾可以降低沉积速度,改善镀层结构和表面形貌,降低织物表面电阻。当Ni2+和K4Fe(CN)6浓度分别为0.0038mol/L和2×10-6时,可以获得最佳的化学镀铜层;当织物上铜镀层的重量为40g/m2时,在100MHz^20GHz频率范围内电磁屏蔽效能均可达到85dB以上。
文摘Rational design and controlled fabrication of efficient and cost-effective electrodes for the oxygen evolution reaction （OER） are critical for addressing the unpre- cedented energy crisis. Nickel-iron layered double hydroxides （NiFe-LDHs） with specific interlayer anions （i.e. phosphate, phosphite, and hypophosphite） were fabricated by a co-predpitation method and investigated as oxygen evolution electrocatalysts. Intercalation of the phosphorus oxoanion enhanced the OER activity in an alkaline solution; the optimal performance （i.e., a low onset potential of 215 mV, a small Tafel slope of 37.7 mV/dec, and stable electrochemical behavior） was achieved with the hypophosphite-intercalated NiFe-LDH catalyst, demonstrating dramatic enhancement over the traditional carbonate-intercalated NiFe-LDH in terms of activity and durability. This enhanced performance is attributed to the interaction between the intercalated phosphorous oxoanions and the edge-sharing MO6 （M = Ni, Fe） layers, which modifies the surface electronic structure of the Ni sites. This concept should be inspiring for the design of more effective LDH-based oxygen evolution electrocatalvsts.
基金financially supported by the Fundamental Research Funds for the Central Universities(DL12CB07)Youth Science Fund of Heilongjiang Province(No.QC2011C102)Heilongjiang Major Research Projects(GA12A102)
文摘The effects of aluminum hypophosphite（AHP） as a synergistic agent on the flame retardancy and thermal degradation behavior of intumescent flame retardant polypropylene composites（PP/IFR） containing ammonium polyphosphate（APP） and triazine charring-foaming agent（CFA） were investigated by limiting oxygen index（LOI）, UL-94 measurement, thermogravimetric analysis（TGA）, cone calorimeter test（CONE）, scanning electron microscopy（SEM） and X-ray photoelectron spectroscopy（XPS）. It was found that the combination of IFR with AHP exhibited an evident synergistic effect and enhanced the flame retardant efficiency for PP matrix. The specimens with the thickness of 0.8 mm can pass UL-94 V-0 rating and the LOI value reaches 33.5% based on the total loading of flame retardant of 24 wt%, and the optimum mass fraction of AHP/IFR is 1：6. The TGA data revealed that AHP could change the degradation behavior of IFR and PP/IFR system, enhance the thermal stability of the IFR and PP/IFR systems at high temperatures and promote the char residue formation. The CONE results revealed that IFR/AHP blends can efficiently reduce the combustion parameters of PP, such as heat release rate（HRR）, total heat release（THR）, smoke production rate（SPR） and so on. The morphological structures of char residue demonstrated that AHP is of benefit to the formation of a more compact and homogeneous char layer on the materials surface during burning. The analysis of XPS indicates that AHP may promote the formation of sufficient char on the materials surface and improve the flame retardant properties.
基金financially supported by the National Natural Science Foundation of China(Nos.50933005 and 51121001)the Program for Changjiang Scholars and Innovative Research Teams in Universities of China(IRT 1026)
文摘Aluminum hypophosphite （AP） was used to prepare flame-retarded thermoplastic polyurethane （FR-TPU） composites, and their flame retardancy, thermal degradation and mechanical properties were investigated by limiting oxygen index （LOI）, vertical burning test （UL-94）, thermogravimetric analysis （TGA）, cone calorimeter （CC） test, Fourier transform infrared （FTIR） spectroscopy, scanning electron microscopy （SEM） and tensile test. TPU containing 30 wt% of AP could reach a V-0 rating in the UL-94 test, and its LOI value was 30.2. TGA tests revealed that AP enhanced the formation of residual chars at high temperatures, and slightly affected the thermal stability of TPU at high temperatures. The combustion tests indicated that AP affected the burning behavior of TPU. The peak of heat release rate （PHRR）, total heat release （THR） and mass loss rate （MLR） greatly reduced due to the incorporation of AP. The tensile test results showed that both the tensile strength and the elongation at break slightly decreased with the addition of AP. The digital photos and SEM micrographs vitrified that AP facilitated the formation of more compact intumescent char layer. Based on these results mentioned above, the flame-retarding mechanism of AP was discussed. Both the self-charring during the decomposing process of AP and its facilitation to the charring of TPU led to the great improvement in the flame retardancy of TPU.
基金The authors thank the "National" Science Council, Taiwan, China for financially supporting (No. NSC95- 2211-E-006-032).
文摘Both citrate and hypophosphite in aqueous solution were degraded by advanced oxidation processes （Fe^2＋/H2O2, UV/Fe^2＋/H2O2, and electrolysis/Fe^2＋/H2O2） in this study. Comparison of these techniques in oxidation efficiency was undertaken. It was found that Fenton process could not completely degrade citrate in the presence of hypophosphite since it caused a series inhibition. Therefore, UV light （photo-Fenton） or electron current （electro-Fenton） was applied to improve the degradation efficiency of the Fenton process. Results showed that both photo-Fenton and electro-Fenton processes could overcome the inhibition of hypophosphite, especially the electro-Fenton.
基金supported by the National Key Research and Development Program of China (2017YFA0206500)the National Natural Science Foundation of China (21671014)the Fundamental Research Funds for the Central Universities (buctrc201522)
文摘Doped phosphide is promising in earthabundant element based catalysts for hydrogen evolution reaction(HER). Here we employ ammonium hypophosphite(NH4H2PO2) to synthesize a novel parallel doped catalyst,nitrogen doped molybdenum phosphide nanoparticles(NPs)supported on nitrogen doped carbon nanotubes(N-MoP/N-CNTs). The NH4H2PO2 as a bifunctional agent severs as both phosphidation agent and nitrogen source, which makes the synthetic route simple and efficient. The as-obtained parallel doped N-MoP/N-CNTs show an overpotential of 103±5 mV at 10 mA cm-2, which is 140 mV lower than that of MoP NPs. The enhanced HER performance is attributed to the electronic effect by doped MoP and CNTs supports. This work provides a facile route to synthesize doped phosphides for the potential applications in hydrogen energy.
基金Supported by the Opening Project of Hubei Three Gorges Laboratory (No.SK213008)the Innovation Fund of Key Laboratory of Green Chemical Process of Ministry of Education (No.GCXP202109)。
文摘Aluminum hypophosphite microspheres(AHP) were synthesized by hydrothermal method using NaH2PO2·H2O and AlCl3·6H2O as raw materials, and then the AHP microspheres were polymerized by surface polymerization of micro-nanospheres with cyclic cross-linked poly(cyclotriphosphazene-co-4,4'-sulfonyldiphenol)(PZS). A new organic-inorganic poly(phosphonitrile)-modified aluminum hypophosphite microspheres(PZS-AHP) were synthesized by encapsulation and applied to flame retardant thermoplastic polyurethane(TPU). The microstructure and chemical composition of the PZS-AHP microsphere were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray spectroscopy. The thermal stability of PZS-AHP microsphere was explored with thermogravimetric analysis. Thermogravimetric data indicate that the PZS-AHP microspheres have excellent thermal stability. The thermal and flame-retarding properties of the TPU composites were evaluated by thermogravimetric(TG), limited oxygen index tests(LOI), and cone calorimeter test(CCT). The TPU composite achieved vertical burning(UL-94) V-0 grade and LOI value reached 29.2% when 10 wt% PZS-AHP was incorporated. Compared with those of pure TPU, the peak heat release rate(pHRR) and total heat release(THR) of TPU/10%PZS-AHP decreased by 82.2% and 42.5%, respectively. The results of CCT indicated that PZS-AHP microsphere could improve the flame retardancy of TPU composites.
