Rubber solutions

Jha and Bhowmick [51] have reported the development and properties of thermoplastic elastomeric blends from poly(ethylene terephthalate) and ACM by solution-blending technique. For the preparation of the blend the two components, i.e., poly(ethylene terephthalate) and ACM, were dried first in vacuum oven. The ACM was dissolved in nitrobenzene solvent at room temperature with occasional stirring for about three days to obtain homogeneous solution. PET was dissolved in nitrobenzene at 160°C for 30 min and the rubber solution was then added to it with constant stirring. The mixture was stirred continuously at 160°C for about 30 min. The blend was then drip precipitated from cold petroleum ether with stirring. The ratio of the petroleum ether/nitrobenzene was kept at 7 1. The precipitated polymer was then filtered, washed with petroleum ether to remove nitrobenzene, and then dried at 100°C in vacuum. 

Violent reactions have occurred between ozone and many chemicals, a small selection being acetylene, alkenes, dialkyl zincs, benzene/rubber solution, bromine, carbon monoxide and ethylene, diethyl ether, hydrogen bromide, and nitrogen oxide. 

A method of manufacturing rubber articles by dipping a former of the shape required into a rubber solution or into compounded,... 

The saturation of the individual fibres of a textile with rubber. The rubber may be in the form of a rubber solution, a natural or synthetic latex. 

The time a rubber solution or dough will remain usable after the addition of the curatives. Potassium Hydroxide Number... 

A true solution consists of molecules or ions of a solid substance uniformly distributed throughout a liquid. A rubber solution is colloidal, i.e., intermediate between a true solution and a coarse suspension. Rubber solutions are used as adhesives and in the manufacture of rubber products by the dipping process. 

A solvent is a substance, usually liquid, in which another substance can be dissolved. Rubber solvents comprise coal-gas products, petroleum distillates, and various chlorinated solvents such as carbon tetrachloride and trichloroethylene. They are used in making rubber solutions for adhesives, doughs for spreading and in freshening uncured rubber surfaces prior to assembly with other components. 

The dipping process, as the name implies, involves the immersion of a former into either a latex, or a rubber solution, and then its slow withdrawal to leave a uniform deposit on the former. Subsequent processes involve, amongst others, drying the deposit, and curing it, if this is required. 

The method consist of passing dried fabric over a spreader roller to eliminate creases, then through a bath of the rubber solution/dough and then squeezing off excess material by passing the dipped fabric through a pair of squeeze rollers. 

Normally only used for further dilution of previously prepared rubber solutions to ensure uniformity. Often used after storage periods for such products as bonding agents to lift deposits from the bottom of delivery and storage drums and to re-establish full dispersion of all the components of the system. 

The continuous mass process is divided into 4 steps rubber solution in styrene monomer, polymerization, devolatilization and compounding. In 1970 N. Platzer (40) drew up a survey of the state of the art. Polymerization is divided into prepolymerization and main polymerization for both steps reactor designs other than the tower reactors shown in Figure 2 have been proposed. Main polymerization is taken to a conversion of 75 to 85% residual monomer and any solvent are separated under vacuum. The copolymer then passes to granulating equipment, frequently through one or more intermediate extruders in which colorant and other auxiliaries are added. 

A sample of the sieved particles was also devulcanized by the phenyllithium method (4). An oven-dried 200 mL beverage bottle was charged with 1 g of 18-60 mesh particles and 40 mL of dry benzene. The bottle was capped with a 1-hole cap (extracted neoprene liner) and 10 mL of 2 M phenyllithium added. The mixture was shaken for 6.5 h at room temperature, then 1.5 mL of methanol added. Finally, 4 mL of methyl iodide was injected. At thi point the mixture comprised a rubber solution and a suspension of salts. An aliquot of the solution was taken for gpc analysis. 

Toy balloons were introduced by Thomas Hancock in 1825 as a do-it-yourself kit that consisted of a rubber solution and a syringe. Vulcanized toy balloons were initially manufactured by J.G. Ingram of London in 1847. The vulcanizing caused the balloons to be nontacky and not susceptible to becoming excessively tacky on hot days. Montgomery Ward had balloons in their catalog by 1889. 

G. Gee, Thermodynamics of rubber solutions and gels, in Advances in Colloid Science, Vol. 2, Interscience, New York (1946). 

Eq. (18). Their experiment provided an opportunity only to fit three of the four unknown constants, namely Dg, c2, and Tg. Tg in the solution was found to be depressed below that known for the rubber. An examination of the concentration dependence of oil diffusion in the same rubber host confirmed the applicability ofEq. (17) below vdil < 0.9 and permitted a measurement ofthe fractional free volume of one or both components of the oil-rubber solution. 

Conductive Rubber, The history of conductive rubber dates back to 1882, when graphite was proposed as a conductor in rubber. Since that time considerable work has been done by various investigators in developing conducting rubber, both natural synthetic. The electricall resistivity of such rubbers may be as low as 100 ohm-cm. A recent technique of incorporating the black (acetylene black) into a rubber solution or cement has been shown to produce rubbers of very high conductivity, having resistivities as low as 1 ohm-cm (Ref 2)... 

The formation of a w/o emulsion with the rubber solution as the oil phase depended, like the production of w/o emulsions with low molecular weight oils, to a large extent on the process conditions. It cannot be ruled out, therefore, that a few of the products which were examined as emulsifying agents during these investigations and which were discarded as ineffective, would have yielded positive results if they had been tested under different conditions. 

To produce w/o emulsions the aqueous phase had to be added to the rubber solution. The reverse order of addition yielded o/w emulsions at a phase volume ratio w o of 1 1 it was impossible to change an o/w emulsion into a w/o emulsion even when good w/o emulsifiers, which displayed only a moderate tendency to produce o/w emulsions, were used. The tendency to form w/o emulsions and the stability of these emulsions increased with the following factors (the tendency to form o/w emulsions decreased) ... 

Thomas Hancock (1786-1865) and Charles Macintosh (1766-1845) a chemist dissolved natural rubber in naphtha obtained by the fractional distillation of coal tar. They, then dipped ordinary cloth in this rubber solution to produce waterproof cloth for making coats. This waterproof coat came to be known as Mackintosh . 

As dimerization competes with polymerization, dimer formation very slightly reduces polymer yield. The toxicity and the smell of VCH are much more relevant. VCH is removed from the rubber solution together with residual monomer and solvent prior to the isolation of the rubber from the polymer solution. As VCH has a higher boiling point than BD and hexane an efficient stripping process has to be used in order to reduce VCH contents to environmentally friendly levels. 

Examples Polycarbonate — chlorobenzene, dichloromethane LLDPE — hexane/cyclohexane SBR-rubber solutions—hexane/cyclohexane... 

Figure 10.3 Solvent and temperature progression when degassing a rubber solution (experimental values)...

Reactivities of Amines in Homogeneous Systems (14, 17). The decrease in the tensile properties of the vulcanized rubber during aging may be attributed to the degradation of the rubber molecule by oxidation. This may be supported by the experimental result in the oxidation of rubber solution. 

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