Sulfur cements

W. C. McBee, T. A. Sullivan, and B. W. Jong, Modfied-Sulfur Cements for Use in Concretes, Flexible Pavings, Coatings, and Grouts, RI 8545, U.S. Bureau of Mines, Washington, D.C., 1981. 

Cyclopentadiene oligomers have been formed by vapor deposition of CPD on kaolin to afford a sorbant for removal of oil from water (71). They are also employed as coatings for controlling release rates of fertilizers (72). Thermal addition of sulfur to a mixture of DCPD and CPD oligomers has led to a number of beneficial appHcations such as waste water oil adsorbant powdery foams (73), plasticized backing for carpets and artificial turfs (74), and in modified sulfur cements for encapsulating low-level radioactive wastes (75). 

T0394 Idaho National Engineering Laboratory/Brookhaven National Laboratory, Modified Sulfur Cement Encapsulation T0410 Institute of Gas Technology, AGGCOM... 

T0394 Idaho National Engineering Laboratory/Brookhaven National Laboratory, Modified Sulfur Cement Encapsulation T0443 IT Corporation, In Situ Geochemical Eixation T0450 IT Corporation, Thermal Destruction Unit T0462 Klean Earth Environmental Company (KEECO, Inc.), KB-1... 

McKinney, P. V., Provisional Methods for Testing Sulfur Cements, ... 

Organic polysulfanes are also important constituents of polysulfide polymers of the Thiokol type, of vulcanized rubber, and of sulfur cement. In addition, there are a few special applications in the oil industry and in medicine. Sulfur-containing polymers have been extensively reviewed by Tobolsky and MacKnight in 1965 and by Duda and Penczek in 1987. ... 

The most important alkene in this context is DCPD or a mixture of di- and tricyclopentadienes. The addition of 5-10% by mass to elemental sulfur, followed by heating to 140 °C results in a complex mixture of polysulfanes and sulfur, which after cooling to 20 °C is no longer brittle but of extremely high mechanical strength (sulfur cement). When the liquid sulfur cement is mixed with suitable pre-heated mineral fillers and cooled to ambient temperature a very useful construction material is obtained (sulfur concrete). 

In contrast to Portland cement and conventional concrete, sulfur cement and sulfur concrete are resistant to aqueous acids and concentrated salt solutions. 

The polysulfanes formed on reaction of DCPD with liquid sulfur have been studied by extraction of sulfur cement and analysis by LC, H-NMR, MS, and other techniques.The initial products are trisulfane and pentasulfane derived from DCPD by addition of S3 or S5 units to the norbomenyl double bond. These monomers are believed to further react with elemental sulfur to form low-molecular mass polymers (CS2 soluble), and on further heating form an insoluble material. The cyclopentenyl unsaturation of DCPD is much less reactive and is still present in the CS2-soluble products. endo-T>CP D reacts more slowly with liquid sulfur at 140 °C than eco-DCPD, while the cyclic trisulfanes of endo- and gxo-DCPD react at almost the same rate with liquid sulfur at 140°C. The stmctures of DCPD-S3, DCPD-S5, and the hkely stmcture of the low-molecular mass polymer, are shown in Figure 8. 

Sulfur Cements Sulfur base cements are heated in a kettle similar to asphalts and joints poured hot, done in several steps to assure the joints are filled before cement cools below flowable temperature. Sulfur cements are plasticized using 0.6% olefin polysulfide (Thiokol ). Other plasticizers have been tried but none have proven as effective as the polysulfide. Sulfur cements are filled with either silica or carbon depending on exposure (carbon in the case of hydrofluoric... 

The chief uses of the polysulfide crude rubbers are in (1) rollers for applying ink, paint, and lacquer (2) hose to carry gasoline, solvents, and paint (3) putties for metal, glass, plastics, and wood (4) paper coatings for gadiets (5) plasticizer for sulfur cements (6) molded compounds in contact with fuels and (7) fabric coatings for diaphragms. 

The early sulfur cements were used to join clay sewer pipe, clay tile, cast iron pipe, paving brick, acid reaction vessels, and for similar applications. The composition of the materials varied but were mostly sulfur containing 1-10% of an organic polysulfide. Silica, carbon black, and wood rosin also were used frequently. However, the compositions varied considerably, and one promising material contained 60% air blown asphalt and 40% sulfur (49). 

Sulfur cements are resistant to attack from water, hydrochloric, nitric, hydrofluoric, sulfuric, phosphoric, and most organic acids. When tested as linings for storing acids at concentrations of 5-90% and at temperatures up to 90 °C, the sulfur coatings were unaflFected generally after several years of service. 

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