Jelle Kaspersma | Technical University of Delft (original) (raw)
Papers by Jelle Kaspersma
Polymer degradation and stability, 2002
This paper deals with the effective flame retardance of polystyrene and polypropylene with alipha... more This paper deals with the effective flame retardance of polystyrene and polypropylene with aliphatic bromine compounds. By studying glow wire and UL94 V2 performance of aliphatic hexabromocyclododecane in polystyrene and the mixed aliphatic/aromatic compound tetrabromobisphenol A bis (2,3-dibromopropyl ether) in polypropylene with and without synergists like antimony trioxide and dicumene, it is made plausible that the combination of chain scission and flame poisoning mechanisms causes these compounds to be so effective. The effectiveness of a synergist depends on the use ratio and can be negative depending on the FR test. Also the effect of neutral fillers like talc is studied and it is shown that particle size has the strongest effect on the FR test which depends most on polymer flow. The effect of polymer molecular weight is in line with the mechanisms involved.
Metall Mater Trans B, 1982
Rates of carburization of low-carbon steel by CH4, C2H2, C2H4, C2H6, and C3H8 in N2 have been mea... more Rates of carburization of low-carbon steel by CH4, C2H2, C2H4, C2H6, and C3H8 in N2 have been measured gravimetrically at 850 �C and 925 �C. Methane appears to be the slowest and acetylene the fastest carburizing agent among the hydrocarbons tested. Hydrogen enhances the rates of carburizing of all hydrocarbons, probably by removing adsorbed oxygen from the steel surface. At high H2/CH4 ratios, H2 will decarburize steel at 925 �C. All hydrocarbons, including CH2, are also involved in gas phase reactions. These reactions may lead to the formation of soot at carburizing temperatures. Sooting is inhibited by the addition of H2 to hydrocarbon-nitrogen gas mixtures. Acetylene appears to be a key intermediate for the formation of soot as the final product of hydrocarbon reactions in the gas phase.
Polymer Degradation and Stability, Dec 31, 2002
This paper deals with the effective flame retardance of polystyrene and polypropylene with alipha... more This paper deals with the effective flame retardance of polystyrene and polypropylene with aliphatic bromine compounds. By studying glow wire and UL94 V2 performance of aliphatic hexabromocyclododecane in polystyrene and the mixed aliphatic/aromatic compound tetrabromobisphenol A bis (2,3-dibromopropyl ether) in polypropylene with and without synergists like antimony trioxide and dicumene, it is made plausible that the combination of chain scission and flame poisoning mechanisms causes these compounds to be so effective. The effectiveness of a synergist depends on the use ratio and can be negative depending on the FR test. Also the effect of neutral fillers like talc is studied and it is shown that particle size has the strongest effect on the FR test which depends most on polymer flow. The effect of polymer molecular weight is in line with the mechanisms involved. #
Polymer Degradation and Stability, Dec 31, 2002
This paper deals with the effective flame retardance of polystyrene and polypropylene with alipha... more This paper deals with the effective flame retardance of polystyrene and polypropylene with aliphatic bromine compounds. By studying glow wire and UL94 V2 performance of aliphatic hexabromocyclododecane in polystyrene and the mixed aliphatic/aromatic compound tetrabromobisphenol A bis (2,3-dibromopropyl ether) in polypropylene with and without synergists like antimony trioxide and dicumene, it is made plausible that the combination of chain scission and flame poisoning mechanisms causes these compounds to be so effective. The effectiveness of a synergist depends on the use ratio and can be negative depending on the FR test. Also the effect of neutral fillers like talc is studied and it is shown that particle size has the strongest effect on the FR test which depends most on polymer flow. The effect of polymer molecular weight is in line with the mechanisms involved. #
Polymer Degradation and Stability, 2002
This paper deals with the effective flame retardance of polystyrene and polypropylene with alipha... more This paper deals with the effective flame retardance of polystyrene and polypropylene with aliphatic bromine compounds. By studying glow wire and UL94 V2 performance of aliphatic hexabromocyclododecane in polystyrene and the mixed aliphatic/aromatic compound tetrabromobisphenol A bis (2,3-dibromopropyl ether) in polypropylene with and without synergists like antimony trioxide and dicumene, it is made plausible that the combination of chain scission and flame poisoning mechanisms causes these compounds to be so effective. The effectiveness of a synergist depends on the use ratio and can be negative depending on the FR test. Also the effect of neutral fillers like talc is studied and it is shown that particle size has the strongest effect on the FR test which depends most on polymer flow. The effect of polymer molecular weight is in line with the mechanisms involved. #
International Journal of Chemical Kinetics, 1975
The rate of hydrogenation of cyclohexene, catalyzed by CoH3(PPh3)3, has been measured under vario... more The rate of hydrogenation of cyclohexene, catalyzed by CoH3(PPh3)3, has been measured under various conditions and, based on these data, a mechanism has been postulated. For the individual steps of the mechanism enthalpy and entropy differences have been determined. The interpretation of these parameters gives evidence for a more detailed mechanism, in which solvent molecules play an important part as “stand-in” for ligands, dissociated from the catalyst species.
Journal of Heat Treating, 1980
Studies using 1010 steel shimstock in a controlled atmosphere tubular furnace have allowed rate c... more Studies using 1010 steel shimstock in a controlled atmosphere tubular furnace have allowed rate constants to be determined for a number of important carburizing and decarburizing reactions. Carburizing data obtained in a small commercial furnace confirm that the combination of CO and H2 to form C and H2O is the major carbon transfer reaction to the parts in a typical furnace system. The hydrocarbon injected in the furnace for enrichment deposits carbon on the heating surfaces initially as a result of catalytic cracking reactions. Due to the temperature differential between heating surfaces and parts, the CO-H2 reaction acts as a “carbon pump” in transferring this carbon to the reactive surface of the parts to be carburized. Carbon control by monitoring the concentration of CO and CO2 or CO, H2, and H2O is most efficient in the later stages of a typical furnace cycle as the carbon concentration at the surface of the parts approaches the carbon potential in the gas phase.
Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science, 1981
The rates of carburization by mixtures of CO, CO2, H2 and H2O in N2 have been measured gravimetri... more The rates of carburization by mixtures of CO, CO2, H2 and H2O in N2 have been measured gravimetrically at 925 °. The rate equation which best describes the experimental data is based on a mechanism which involves a rapid surface dissociation of CO into carbon and oxygen atoms, and a subsequent rate determining step between this atomic oxygen and either CO or H2. The CO-H2 system carburizes much faster than CO alone, because H2 combines faster with atomic oxygen than does CO. The carburizing rate constant for CO-H2 is 44 times that for CO alone. The mechanism is confirmed by the additivity of the separate rates for the CO-H2 mixtures and for CO alone.
Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science, 1982
Rates of carburization of low-carbon steel by CH4, C2H2, C2H4, C2H6, and C3H8 in N2 have been mea... more Rates of carburization of low-carbon steel by CH4, C2H2, C2H4, C2H6, and C3H8 in N2 have been measured gravimetrically at 850 °C and 925 °C. Methane appears to be the slowest and acetylene the fastest carburizing agent among the hydrocarbons tested. Hydrogen enhances the rates of carburizing of all hydrocarbons, probably by removing adsorbed oxygen from the steel surface. At high H2/CH4 ratios, H2 will decarburize steel at 925 °C. All hydrocarbons, including CH2, are also involved in gas phase reactions. These reactions may lead to the formation of soot at carburizing temperatures. Sooting is inhibited by the addition of H2 to hydrocarbon-nitrogen gas mixtures. Acetylene appears to be a key intermediate for the formation of soot as the final product of hydrocarbon reactions in the gas phase.
The rates of carburization by mixtures of CO, CO2, H2 and H2O in N2 have been measured gravimetri... more The rates of carburization by mixtures of CO, CO2, H2 and H2O in N2 have been measured gravimetrically at 925 °. The rate equation which best describes the experimental data is based on a mechanism which involves a rapid surface dissociation of CO into carbon and oxygen atoms, and a subsequent rate determining step between this atomic oxygen and either CO or H2. The CO-H2 system carburizes much faster than CO alone, because H2 combines faster with atomic oxygen than does CO. The carburizing rate constant for CO-H2 is 44 times that for CO alone. The mechanism is confirmed by the additivity of the separate rates for the CO-H2 mixtures and for CO alone.
Rates of carburization of low-carbon steel by CH4, C2H2, C2H4, C2H6, and C3H8 in N2 have been mea... more Rates of carburization of low-carbon steel by CH4, C2H2, C2H4, C2H6, and C3H8 in N2 have been measured gravimetrically at 850 °C and 925 °C. Methane appears to be the slowest and acetylene the fastest carburizing agent among the hydrocarbons tested. Hydrogen enhances the rates of carburizing of all hydrocarbons, probably by removing adsorbed oxygen from the steel surface. At high H2/CH4 ratios, H2 will decarburize steel at 925 °C. All hydrocarbons, including CH2, are also involved in gas phase reactions. These reactions may lead to the formation of soot at carburizing temperatures. Sooting is inhibited by the addition of H2 to hydrocarbon-nitrogen gas mixtures. Acetylene appears to be a key intermediate for the formation of soot as the final product of hydrocarbon reactions in the gas phase.
Polymer degradation and stability, 2002
This paper deals with the effective flame retardance of polystyrene and polypropylene with alipha... more This paper deals with the effective flame retardance of polystyrene and polypropylene with aliphatic bromine compounds. By studying glow wire and UL94 V2 performance of aliphatic hexabromocyclododecane in polystyrene and the mixed aliphatic/aromatic compound tetrabromobisphenol A bis (2,3-dibromopropyl ether) in polypropylene with and without synergists like antimony trioxide and dicumene, it is made plausible that the combination of chain scission and flame poisoning mechanisms causes these compounds to be so effective. The effectiveness of a synergist depends on the use ratio and can be negative depending on the FR test. Also the effect of neutral fillers like talc is studied and it is shown that particle size has the strongest effect on the FR test which depends most on polymer flow. The effect of polymer molecular weight is in line with the mechanisms involved.
Metall Mater Trans B, 1982
Rates of carburization of low-carbon steel by CH4, C2H2, C2H4, C2H6, and C3H8 in N2 have been mea... more Rates of carburization of low-carbon steel by CH4, C2H2, C2H4, C2H6, and C3H8 in N2 have been measured gravimetrically at 850 �C and 925 �C. Methane appears to be the slowest and acetylene the fastest carburizing agent among the hydrocarbons tested. Hydrogen enhances the rates of carburizing of all hydrocarbons, probably by removing adsorbed oxygen from the steel surface. At high H2/CH4 ratios, H2 will decarburize steel at 925 �C. All hydrocarbons, including CH2, are also involved in gas phase reactions. These reactions may lead to the formation of soot at carburizing temperatures. Sooting is inhibited by the addition of H2 to hydrocarbon-nitrogen gas mixtures. Acetylene appears to be a key intermediate for the formation of soot as the final product of hydrocarbon reactions in the gas phase.
Polymer Degradation and Stability, Dec 31, 2002
This paper deals with the effective flame retardance of polystyrene and polypropylene with alipha... more This paper deals with the effective flame retardance of polystyrene and polypropylene with aliphatic bromine compounds. By studying glow wire and UL94 V2 performance of aliphatic hexabromocyclododecane in polystyrene and the mixed aliphatic/aromatic compound tetrabromobisphenol A bis (2,3-dibromopropyl ether) in polypropylene with and without synergists like antimony trioxide and dicumene, it is made plausible that the combination of chain scission and flame poisoning mechanisms causes these compounds to be so effective. The effectiveness of a synergist depends on the use ratio and can be negative depending on the FR test. Also the effect of neutral fillers like talc is studied and it is shown that particle size has the strongest effect on the FR test which depends most on polymer flow. The effect of polymer molecular weight is in line with the mechanisms involved. #
Polymer Degradation and Stability, Dec 31, 2002
This paper deals with the effective flame retardance of polystyrene and polypropylene with alipha... more This paper deals with the effective flame retardance of polystyrene and polypropylene with aliphatic bromine compounds. By studying glow wire and UL94 V2 performance of aliphatic hexabromocyclododecane in polystyrene and the mixed aliphatic/aromatic compound tetrabromobisphenol A bis (2,3-dibromopropyl ether) in polypropylene with and without synergists like antimony trioxide and dicumene, it is made plausible that the combination of chain scission and flame poisoning mechanisms causes these compounds to be so effective. The effectiveness of a synergist depends on the use ratio and can be negative depending on the FR test. Also the effect of neutral fillers like talc is studied and it is shown that particle size has the strongest effect on the FR test which depends most on polymer flow. The effect of polymer molecular weight is in line with the mechanisms involved. #
Polymer Degradation and Stability, 2002
This paper deals with the effective flame retardance of polystyrene and polypropylene with alipha... more This paper deals with the effective flame retardance of polystyrene and polypropylene with aliphatic bromine compounds. By studying glow wire and UL94 V2 performance of aliphatic hexabromocyclododecane in polystyrene and the mixed aliphatic/aromatic compound tetrabromobisphenol A bis (2,3-dibromopropyl ether) in polypropylene with and without synergists like antimony trioxide and dicumene, it is made plausible that the combination of chain scission and flame poisoning mechanisms causes these compounds to be so effective. The effectiveness of a synergist depends on the use ratio and can be negative depending on the FR test. Also the effect of neutral fillers like talc is studied and it is shown that particle size has the strongest effect on the FR test which depends most on polymer flow. The effect of polymer molecular weight is in line with the mechanisms involved. #
International Journal of Chemical Kinetics, 1975
The rate of hydrogenation of cyclohexene, catalyzed by CoH3(PPh3)3, has been measured under vario... more The rate of hydrogenation of cyclohexene, catalyzed by CoH3(PPh3)3, has been measured under various conditions and, based on these data, a mechanism has been postulated. For the individual steps of the mechanism enthalpy and entropy differences have been determined. The interpretation of these parameters gives evidence for a more detailed mechanism, in which solvent molecules play an important part as “stand-in” for ligands, dissociated from the catalyst species.
Journal of Heat Treating, 1980
Studies using 1010 steel shimstock in a controlled atmosphere tubular furnace have allowed rate c... more Studies using 1010 steel shimstock in a controlled atmosphere tubular furnace have allowed rate constants to be determined for a number of important carburizing and decarburizing reactions. Carburizing data obtained in a small commercial furnace confirm that the combination of CO and H2 to form C and H2O is the major carbon transfer reaction to the parts in a typical furnace system. The hydrocarbon injected in the furnace for enrichment deposits carbon on the heating surfaces initially as a result of catalytic cracking reactions. Due to the temperature differential between heating surfaces and parts, the CO-H2 reaction acts as a “carbon pump” in transferring this carbon to the reactive surface of the parts to be carburized. Carbon control by monitoring the concentration of CO and CO2 or CO, H2, and H2O is most efficient in the later stages of a typical furnace cycle as the carbon concentration at the surface of the parts approaches the carbon potential in the gas phase.
Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science, 1981
The rates of carburization by mixtures of CO, CO2, H2 and H2O in N2 have been measured gravimetri... more The rates of carburization by mixtures of CO, CO2, H2 and H2O in N2 have been measured gravimetrically at 925 °. The rate equation which best describes the experimental data is based on a mechanism which involves a rapid surface dissociation of CO into carbon and oxygen atoms, and a subsequent rate determining step between this atomic oxygen and either CO or H2. The CO-H2 system carburizes much faster than CO alone, because H2 combines faster with atomic oxygen than does CO. The carburizing rate constant for CO-H2 is 44 times that for CO alone. The mechanism is confirmed by the additivity of the separate rates for the CO-H2 mixtures and for CO alone.
Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science, 1982
Rates of carburization of low-carbon steel by CH4, C2H2, C2H4, C2H6, and C3H8 in N2 have been mea... more Rates of carburization of low-carbon steel by CH4, C2H2, C2H4, C2H6, and C3H8 in N2 have been measured gravimetrically at 850 °C and 925 °C. Methane appears to be the slowest and acetylene the fastest carburizing agent among the hydrocarbons tested. Hydrogen enhances the rates of carburizing of all hydrocarbons, probably by removing adsorbed oxygen from the steel surface. At high H2/CH4 ratios, H2 will decarburize steel at 925 °C. All hydrocarbons, including CH2, are also involved in gas phase reactions. These reactions may lead to the formation of soot at carburizing temperatures. Sooting is inhibited by the addition of H2 to hydrocarbon-nitrogen gas mixtures. Acetylene appears to be a key intermediate for the formation of soot as the final product of hydrocarbon reactions in the gas phase.
The rates of carburization by mixtures of CO, CO2, H2 and H2O in N2 have been measured gravimetri... more The rates of carburization by mixtures of CO, CO2, H2 and H2O in N2 have been measured gravimetrically at 925 °. The rate equation which best describes the experimental data is based on a mechanism which involves a rapid surface dissociation of CO into carbon and oxygen atoms, and a subsequent rate determining step between this atomic oxygen and either CO or H2. The CO-H2 system carburizes much faster than CO alone, because H2 combines faster with atomic oxygen than does CO. The carburizing rate constant for CO-H2 is 44 times that for CO alone. The mechanism is confirmed by the additivity of the separate rates for the CO-H2 mixtures and for CO alone.
Rates of carburization of low-carbon steel by CH4, C2H2, C2H4, C2H6, and C3H8 in N2 have been mea... more Rates of carburization of low-carbon steel by CH4, C2H2, C2H4, C2H6, and C3H8 in N2 have been measured gravimetrically at 850 °C and 925 °C. Methane appears to be the slowest and acetylene the fastest carburizing agent among the hydrocarbons tested. Hydrogen enhances the rates of carburizing of all hydrocarbons, probably by removing adsorbed oxygen from the steel surface. At high H2/CH4 ratios, H2 will decarburize steel at 925 °C. All hydrocarbons, including CH2, are also involved in gas phase reactions. These reactions may lead to the formation of soot at carburizing temperatures. Sooting is inhibited by the addition of H2 to hydrocarbon-nitrogen gas mixtures. Acetylene appears to be a key intermediate for the formation of soot as the final product of hydrocarbon reactions in the gas phase.