Analysis of Highly Exothermic Reactions by DSC

Duswalt, Allen A.

doi:10.1007/978-1-4757-0001-5_38

Cited by 8 publications

(6 citation statements)

References 3 publications

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“…[20][21][22][23][24]) supported this conjecture. These comments indicate that the objections to CHETAH raised in the first NBS study may not be appliable to explosives.…”

Section: Second Appraisal Of Methodssupporting

confidence: 63%

A third appraisal of methods for estimating self-reaction hazards

Churney¹,

Garvin²

1980

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“…[20][21][22][23][24]) supported this conjecture. These comments indicate that the objections to CHETAH raised in the first NBS study may not be appliable to explosives.…”

Section: Second Appraisal Of Methodssupporting

confidence: 63%

A third appraisal of methods for estimating self-reaction hazards

Churney¹,

Garvin²

1980

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“…Rate constants, when calculated using Eq. [3], have units of reciprocal seconds. The errors associated with the temperature measurement (1%) and area Calculations (<1%) when taken with a data acquisition system and reduced on a computer are smaller than the error (which is unknown) made 10x10"3 in assuming that the system is homogeneous when it is more likely to be heterogeneous.…”

Section: Methodsmentioning

confidence: 99%

“…The method, described in du Pont Applications Brief No. 8 (2), applies to first-order reactions and is used extensively in kinetic studies of the thermal decomposition of polymer materials (3,4) and explosives (5)(6)(7). Currently, there are no reports on kinetic studies of the nature presented here.…”

mentioning

confidence: 99%

DSC Study of Two Reactions in the Lithium‐Boron Alloy System

Ernst

1982

J. Electrochem. Soc.

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in an earlier paper by Dallek, Ernst, and Larrick (1) the differential scanning calorimetry technique (DSC) was used to determine the reactions that occur in the lithium-boron (Li-B) system. This was part of an effort to develop the Li-B alloy for use as an anode material in thermal batteries. A minor objective was to determine the phase diagram. However, the two compounds LiB3 [25.0 atomic percent (a/o) Li] and LiTB6 (53.8 a/o Li) are products of irreversible reactions, and therefore an equilibrium phase diagram for the alloy system could not be determined. The two reactions areThe reactions are complex in nature and there are a number of factors that influence the type of end product (LiTB6 and Li) obtained. Examples of these are heating rate, stirring vs. convection, and composition(1). It was noted in this earlier work that certain boron samples dissolved more readily than other boron samples and that the start of the first reaction was sometimes detectable as soon as the lithium melted. A possible explanation is that the boron oxide present on the surface of the boron may have some influence on the reaction. The present paper discusses the effect of boron particle size on the rate of the reactions in the lithium-boron system as determined by DSC experiments. The rate constants for the two exothermic reactions (1, 2) were first calculated using data obtained earlier (1). The method, described in du Pont Applications Brief No. 8 (2), applies to first-order reactions and is used extensively in kinetic studies of the thermal decomposition of polymer materials (3, 4) and explosives (5-7). Currently, there are no reports on kinetic studies of the nature presented here. Two criteria for applying this method are that the reaction be first order, and homogeneous. The first exothermic reaction can be considered to be first order because there is always excess lithium present; however, excess lithium is only present for the second exothermic reaction at lithium concentrations greater than 70 a/o. Because of the liquid solid interfaces between Li and B and Li and LIB,, the reactions are heterogeneous and not homogeneous. However, the half-lifes as determined by this method were in good agreement with the observations made during actual alloy preparations and indicated that more work in this area was warranted since this information would be helpful when preparing larger amounts of the alloy.

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“…A heating and cooling rate of 10"Cminp' was used. The time necessary for crystallization of PUS was obtained using the procedure proposed by Duswalt [24]: After melting the PU between 35 and 100°C, the temperature was decreased to 25°C and the evolution of heat with time under isothermal conditions was monitored until a crystallization peak appeared.…”

Section: Dscmentioning

confidence: 99%

Characterization of Thermoplastic Polyurethanes Prepared Using Different Macroglycols

Sánchez-Adsuar

Martı́n-Martı́nez

1998

The Journal of Adhesion

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Three polyurethane elastomers (PUS) were prepared using macroglycols of different nature (E-polycaprolactone, polyadipate of I ,6-hexanediol) and length of the hydrocarbon chain (polyadipate of 1,4-butanediol, polyadipate of 1,6-hexanediol). The PUS were characterized using Gel Permeation Chromatography, Differential Scanning Calorimetry, Wide X-ray angle Diffraction, Dynamic Thermal Mechanical Analysis, stress-controlled rheometry and stress-strain experiments. The surface properties were evaluated from contact angle measurements. The PUS were used as raw materials for solvent-based adhesives, whose adhesion properties were measured from T-peel strength of plasticized poly(viny1 chloride) (PVC)/polyurethane adhesive joints. The use of polyadipate of I ,6-hexanediol produced a polyurethane with high crystallinity (i.e. poor rheological and mechanical properties) and enhanced interactions between soft segments. Low adhesion was obtained in joints produced with this polyurethane and a cohesive failure of the adhesive was produced. The decrease in the polyadipate hydrocarbon chain length decreased the degree of crystallinity between polymer chains, therefore, no reduction in rheological and mechanical properties was obtained; a higher joint strength was also obtained. In this study the best performance was obtained with the polyurethane based on E-polycaprolactone, presumably because of its higher surface energy and reduced crystallinity. The properties of the polyurethanes prepared in this study were more affected by the characteristics of the macroglycol, and the crystallinity of the polyurethane had a more marked effect on the properties than the degree of phase separation.

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Analysis of Highly Exothermic Reactions by DSC

Cited by 8 publications

References 3 publications

A third appraisal of methods for estimating self-reaction hazards

A third appraisal of methods for estimating self-reaction hazards

DSC Study of Two Reactions in the Lithium‐Boron Alloy System

Characterization of Thermoplastic Polyurethanes Prepared Using Different Macroglycols

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