Liquid sulfur-dicyclopentadiene (DCP) solutions at 140°Cundergo bulk copolymerization where the melt viscosity and surface tension of the solutions increase with time. A general melt viscosity equation: η = ηo exp(aX b t), at constant temperature, has been developed, where η is the viscosity at time t for an S8-DCP feed composition of DCP mole fraction X; and ηo (in viscosity units), a (in time -1 ), and b (a dimensionless number, + ve for X < 0.5 and -ve for X > 0.5) are empirical constants. The structure of the sulfurated products has been analyzed by NMR. Sulfur noncrystallizable copolymeric compositions have been obtained as shown by thermal analysis (DSC). Dodecyl polysulfide is a viscosity suppressor and a plasticizer for the S8-DCP system.
S ulfur is a readily available, high-purity and low-cost material (I). In
in the western world 34.2 and 30.6 million tons of all forms of sulfur were produced and consumed, respectively (2). Fike (I) has pointed out some potential applicaitons of this material.Sulfur is used directly in sulfur-additive solutions which are used as coatings (3,4,5,6). Dicyclopentadiene is a potentially cheap material that can form copolymers with liquid sulfur. The patent literature reports applications of the sulfur-dicyclopentadiene system in sprayable coatings, rubber vulcanizates, etc. However, very little has been written on the chemistry, characterization, and properties of this system.
Chemistry of the Sulfur-Die y dopent adiene ReactionBicyclo (2.2.1) heptene (norbornene), I, is a strained olefin. Dicyclo pentadiene (DCP), II, is a substituted norbornene, and it has two stereo
SynopsisThe base-catalyzed sulfur-1,2-ethanedithiol reactions appear to follow pseudo first-order kinetics as determined by TGA. The activation energy has been determined to be 26.1 kcal/mol with either cyclo-octameric or catenapolymeric sulfur.
Liquid sulfur–olefinic reactions at 140°C forming crosslinked polysulfide polymers have been investigated. A systematic approach to the characterization and some structure–property studies on these new polymeric materials has been presented. The olefinic systems of interest are endo‐and exo‐dicyclopentadiene and an oligomeric alkenyl polysulfide. Equimolar S8–olefinic system copolymers are amorphous and they show no tendency for sulfur crystallization. A correlation has been drawn between chemical structure and glass transition temperature of the copolymers and terpolymers. Mechanical properties and, in particular, chemical stress relaxation of the crosslinked polysulfide polymers have been investigated.
The reaction of thiols with sulfur in the temperature range 130-160°C to form polysulfides, RS,R/ArS,Ar, where x is the rank of sulfur, has been investigated in some detail.lS2 A free radical mechanism has been proposed for the reaction. It also has been reported that the reaction is base catalyzed.' In the presence of an amine catalyst, the reaction has been reported to occur even at ambient temperature.3 Diethyl amine has been found to be a very effective catalyst in the present study over a temperature range 20-50°C.The base-catalyzed reaction of 2 mole of dodecyl thiol with 3 g atom of sulfur, 2CHpCH-CH2-SH
Standardized botanical formulations have often yielded promising results in the treatment of debilitating joint pains such as those encountered in Osteoarthritis (OA) and Rheumatoid Arthritis (RA). We report a novel formulation of essentials oils made from the Generally Recognized as Safe (GRAS) family of plants widely used in Ayurveda namely Kattrna (CC‐Cymbopogon citratus) (3.0%), Sati (Hedychium spicatum) (1.0%) and Tumuru (ZA‐ Zanthoxylum alatum) oil (1.0%) along with Menthol (M‐ Mentha arvensis) (1.3%) in a non‐greasy cream base which can provide relief against joint pains arising out of arthritis. The formulation was designed as a topical cream for applying around the affected joint. Its purity was confirmed through HPLC and GC‐MS analysis by comparing with identifiable marker components. The formulation patented as HerboJoint was able to substantially bring down the levels of inflammatory cytokines TNF‐α, IL‐6 and IL‐1β in a Type II collagen induced mouse arthritis model. In human clinical trials, the formulation significantly decreased joint pain, joint swelling and joint stiffness arising out of Osteoarthritis and Rheumatoid Arthritis by 2.2, 2.7 and 3.6 times respectively and provided relief to about 90% of patients selected randomly. The corresponding TNF‐α levels in the sera of patients also decreased substantially thus indicating that the formulation was effective in management of both OA and RA. The present invention based on synergistic action of Essential Oils and Menthol is believed to provide a significant relief to these extremely painful and potentially incurable medical conditions.
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