Thermal analysis of polymers. VIII. Dilatometric and thermal optical behavior of sulfur

Miller, Gerald W.

doi:10.1002/app.1971.070150816

Cited by 21 publications

(9 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the work of Ficara and Moreira, there are two endothermic peaks at 108.25 °C and 119.50 °C for the DSC of standard sulfur, which represent the α-sulfur to β-sulfur transition and the melting of sulfur, respectively (Ficara and Moreira, 1988). Their measurement conditions are very close to this study; thus, the first peak at 108.2 °C could be assigned to the transformation of α-sulfur into β-sulfur (Laitinen and Niinisto, 1978;Miller, 1971;Thackray, 1970).…”

Section: Elemental Composition and Mineral Phases In The Leach Residuesupporting

confidence: 75%

Characterization of elemental sulfur in chalcopyrite leach residues using simultaneous thermal analysis

Lin

et al. 2019

Hydrometallurgy

View full text Add to dashboard Cite

A key component in the atmospheric leaching of metal sulfides is the oxidation of sulfide to either elemental sulfur or hexavalent sulfur. The final oxidation state of sulfur significantly influences the economic viability of a leaching process because of its effects on oxygen consumption, acid generation, and surface passivation. Thus, in the process of developing new leaching technologies, it is important to both characterize and quantify the sulfur oxidation products. In this work, a new method based on Simultaneous Thermal Analysis (STA) is established for the quantification and thermal characterization of elemental sulfur in chalcopyrite leach residues. The STA method refers to the simultaneous application of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The DSC measurements yield information on phase transformation, which can be used to identify the sulfur allotropes. The linear relationship between the melting enthalpy of β-sulfur determined by DSC and the sulfur content determined by TGA is expediently used to quantify the unknown sulfur content in leach residues.

show abstract

Section: Elemental Composition and Mineral Phases In The Leach Residuesupporting

confidence: 75%

Characterization of elemental sulfur in chalcopyrite leach residues using simultaneous thermal analysis

Lin

et al. 2019

Hydrometallurgy

View full text Add to dashboard Cite

show abstract

“…Of these, the only thermodynamically-stable polymorphs are orthorhombic c~-sulfur, stable at NTP, and monoclinic/~-sulfur, stable only in the narrow temperature range between 95.4 ~ and its melting point [2]. The stability ranges and other thermal properties of e-and fl-sulfur have also been established by modern thermoanalytical methods [3,4].The third well-known polymorph of cyclo-octasulfur is monoclinic y-sulfur, which has recently been structurally characterized by X-ray diffraction methods [5]. Although y-sulfur itself is not thermodynamically stable relative to the ~-and//-forms, it has been reported that this structure type is found in sulfur crystals containing approximately 10-45~o selenium [6][7][8][9].…”

mentioning

confidence: 97%

Thermal behaviour of the monoclinic allotropesγ-sulfur andα-selenium and some structurally related sulfur-selenium compounds

Laitinen¹,

Niinistö²

1978

Journal of Thermal Analysis

View full text Add to dashboard Cite

The thermal behaviour of 7-sulfur, monoclinic c~-Se, S6Se2, S~S%, SaSea and $3Se5 has been studied by hot-stage microscopy and differential scanning calorimetry. X-ray diffraction results show that S~,Se~ and SsSe 3 are isostructural with S~/, but S~Sea and $3Se5 are isostructural with monoclinic a-Se. The melting of S~. is accompanied by rapid crystallization of Sa, which often occurs almost simultaneously with melting. The melting of S~;S%, S5S%, SaSe 4 and S:~Sez is irreversible as the compounds decompose on melting. For monoclinic c~-Se no phase transformation to monoclinic fl-Se was observed at 110--120 ~ but it changes to hexagonal ~-Se when the temperature is over 120 ~ .The existence of several crystalline modifications of cyclo-octasulfur has been reported [1 ]. Of these, the only thermodynamically-stable polymorphs are orthorhombic c~-sulfur, stable at NTP, and monoclinic/~-sulfur, stable only in the narrow temperature range between 95.4 ~ and its melting point [2]. The stability ranges and other thermal properties of e-and fl-sulfur have also been established by modern thermoanalytical methods [3,4].The third well-known polymorph of cyclo-octasulfur is monoclinic y-sulfur, which has recently been structurally characterized by X-ray diffraction methods [5]. Although y-sulfur itself is not thermodynamically stable relative to the ~-and//-forms, it has been reported that this structure type is found in sulfur crystals containing approximately 10-45~o selenium [6][7][8][9]. When the selenium content increases to 50 ~ and above, the prevailing structure is that of monoclinic ~-selenium. The nature of these sulfur-selenium crystals was not realized, however, until Hawes [10] showed that definite ring compotmds of type Ss-nSen may be crystallized from melts and solutions containing both these chalcogens.The present investigation was undertaken in order to detect, by the DSC method, possible polymorphic transformations and other thermally induced changes occurring in y-sulfur, in monoclinic e-selenium, and in some of the structurally related compounds of the composition Ss-nS%. Obviously, due to its instability and difficulties involved in preparing larger quantities of 7-sulfur, no such study of the pure phase has been done. It also seems that the thermal behaviour of monoclinic a-selenium has not been studied by modern instrumental methods, in spite of the controversy regarding the existence of a phase transition to the 7*

show abstract

“…The monoclinic β-S 8 form exhibits the dominant melt transition at 119 ºC and upon continued heating the molten sulfur undergoes equilibrium polymerization ( Fig. 3) [17][18][19][20][21][22].…”

Section: Polymeric Sulfurmentioning

confidence: 99%

Polymerizations with elemental sulfur: A novel route to high sulfur content polymers for sustainability, energy and defense

Griebel

Glass

Char

et al. 2016

Progress in Polymer Science

375

254

View full text Add to dashboard Cite

Recent developments in the polymerizations of elemental sulfur (S 8 ) to prepare high sulfur content polymers are reviewed. While the homopolymerization of S 8 via ring-opening processes to prepare high molar mass polymeric sulfur has long been known, this form of polymeric sulfur is chemically unstable and depolymerizes back to S 8 . In the current report, we discuss the background into the production of sulfur via petroleum refining and the challenges associated with utilizing S 8 as a chemical reagent for materials synthesis. To circumvent these long standing challenges in working with sulfur, the use of S 8 as a reaction medium and comonomer in a process termed, inverse vulcanization, was developed to prepare chemically stable and processable sulfur copolymers. Furthermore, access to polymeric materials with a very high content of sulfur-sulfur (S-S) bonds enabled for the first time the creation of materials with useful (electro)chemical and optical properties which are reviewed for use in Li-S batteries, IR imaging technology and self-healing materials.

show abstract

Thermal analysis of polymers. VIII. Dilatometric and thermal optical behavior of sulfur

Cited by 21 publications

References 2 publications

Characterization of elemental sulfur in chalcopyrite leach residues using simultaneous thermal analysis

Characterization of elemental sulfur in chalcopyrite leach residues using simultaneous thermal analysis

Thermal behaviour of the monoclinic allotropesγ-sulfur andα-selenium and some structurally related sulfur-selenium compounds

Polymerizations with elemental sulfur: A novel route to high sulfur content polymers for sustainability, energy and defense

Contact Info

Product

Resources

About