Rubber plants

Originally from China, Rhus vernicefera has been under cultivation in Japan since the sixth century AD. The latex is collected in the same way as the rubber plant Hevea brasiliensis. The product is known as urushiol, which consists mostly of dihydric phenols of structures (Fig. 6) and is used as lacquers. 

Figure 12-2 Scale Model used in the construction of an ethylene-propylene synthetic rubber plant. The completed plant is partially shown in the background. The model is built to a scale of 3/8 inch to 1 foot. After construction was completed, it was used to train technicians. Courtesy of Uniroyal.

A genus of trees yielding a good type of natural rubber, of little commercial importance nowadays. The Ficus elastica is the well-known ornamental rubber plant. 

He knew more about rubber than anything else. A synthetic-rubber factory had much in common with him civilized, neat, more reminiscent of perfected nature than of Man. A rubber plant had to be absolutely clean a speck of dust mingling with the liquid rubber could mean a blowout on the highway some day. To plan a rubber factory, you did not begin with materials you put your finger to the wind, because the wind had to blow in the right direction to take off the carbide dust so that it "would not be thrown in your neighbor s face."... 

The judges of the court listened as the soldiers had, as if waiting for a twig to crackle. Somehow the fortunes of war had placed this picture of a spotless industrial installation in a horrible setting, beside a river (not the calm Hudson or the turbulent Rhine) that ran red with a dye no chemist could synthesize. There sprawled the buna-rubber plant, and three kilometers away was a concentra-... 

All I m saying is that we can use a simpler method of proof from now on, one that would reflect back on the proof that s already in. It s hard to take the rearmament up the line. It s not so hard with some of the things that happened at Auschwitz. For example, Farben built its buna-rubber plant near Auschwitz and put the engineer Duerrfeld in charge. And then we show that Duerrfeld s boss, Ambros, knew that concentration-camp inmates were being used at the plant, and he reported this to Ter Meer and the other members of the technical committee. But these technical-committee members were also members of the board. In this way we can show not only what kind of men these defendants are, but also begin to show responsibility all the way up to the top."... 

Buetefisch then looked over the Auschwitz site. Plans for the buna-rubber plant were ready. "So the power plants, the roads and waterways and individual buildings that had originally been planned for rubber had to be planned again — to have one power plant only, one waterworks, one pipe bridge, and one waterway and this project bad to be pushed very quickly so that one could catch up with the others."... 

Q. And within the framework of this Four Year Plan, you took the initiative in forcing foreign workers to produce in the rubber plants ... 

The official on Goering s staff who so irresponsibly pushes matters concerning the construction of rubber plants is Dr. Krauch. I felt that for once I.G. should put a stop to this, since it was in the interests neither of the Reich nor of I.G. 

Whereas, at the beginning of the thirties, polystyrene had been the driving force in the styrene monomer and polystyrene fields, this development was soon reversed. Under Germany s efforts to become self-sufficient there was a much bigger demand for styrene monomer for the manufacture of synthetic rubber than for polystyrene. As early as 1938 approximately 2500 t of styrene monomer was produced in Ludwigshafen for the newly commissioned rubber plants. When the Allies were cut off from their Asian rubber plantations in the Second World War, the U.S.A. followed suit with large styrene monomer capacities for the manufacture of rubber. Thus there were big capacities for styrene monomer available by 1945 for other uses. 

Edgar, A. T., Manual of Rubber Planting (Malaya), Watney and Powell,... 

Rubber Plant Field Station, Turrialba, Costa Rica (1945). 

Organic toxic pollutants found at emulsion crumb rubber plants come from the raw materials, impurities in the raw materials, and additives to noncontact cooling water. BOD, COD, and TSS levels may also reach high loadings. 

General Molding, Extruding, and Fabricating Rubber Plants... 

There are 13 solution crumb rubber plants in the United States. Twelve of these plants discharge treated wastewater to surface streams the other plant discharges its treated wastewater into a neighboring oil refinery s noncontact cooling water system. 

Tables 18 and 19 show pollutant removal efficiencies at two selected solution crumb rubber plants.

Table 16 Toxic Pollutant Removal Efficiency at Emulsion Crumb Rubber Plant 000012, Verification Data (Treatment Technology Activated Sludge, Discharge Point Surface Stream)...

Table 18 Toxic Pollutant Removal Efficiency at Solution Crumb Rubber Plant 000005...

Five workers at an Ohio rubber plant became ill with symptoms, including yellow discoloration of the hands, blue discoloration of the lips and nail beds, headache, nausea, chest pain, dizziness, confusion, and difficulty in concentrating one worker suffered a seizure." Medical examinations showed that blood methemoglobin levels ranged from 3.8% to 41.2%. Effects were attributed to dermal exposure to an adhesive containing 1% by weightp-DNB. After replacement of the adhesive, symptoms disappeared and methemoglobin levels were within normal limits. 

Lloyd, F. E. "Guayule ( Parthenium argentatum Gray) A rubber-plant of the Chihuahuan Desert". Carnegie Institute of Washington, 1911, 213 pp. 

Example 4 In pineapple fields where the intercrop of the rubber plant and sweet potato were used, it was observed that these fields were less weedy than the pineapple-rubber intercrop fields. It was also noted that in the pineapple-sweet potato Intercrop fields, there were more sweet potatoes harvested. Whether the sweet potatoes produced the allelochemicals to suppress the gaseous weeds in the pineapple fields or the pineapples produced the allelochemicals to stimulate the growth of the sweet potatoes or the rubber plants produced the allelochemicals to suppress the weeds has yet to be studied. 

Latex originally meant the sap of the rubber plant and is a dispersion of particulate rubber. Emulsion polymerization produces a similar dispersion of synthetic rubber or polymers and was rapidly developed to obtain a substitute for natural rubber during World War II. Therefore the product of emulsion polymerization was first called polymer latex, but is now known simply as latex. Sometimes the product of emulsion polymerization is called polymer emulsion. But this terminology is incorrect for latices of solid polymer particles, because emulsion indicates liquid-in-liquid dispersion (1). 

Sally follows you into your high-ceilinged office crammed with books and electrical equipment. Lying scattered between the sofa and chairs are three oscilloscopes, a tall Indian rubber plant, and a Rubik s cube. A small blackboard hangs on the wall. The bulletproof, floor-to-ceiling windows give the appearance of a room more spacious than it really is. Sally eyes the electrical hardware. What s all this ... 

TWAg measurements in Canadian nitrile rubber plants averaged 2 ppm [4.4 mg/m ]... 

Mortality associated with acrylonitrile exposure was evaluated as part of a study of 15 643 male workers in a rubber plant in the United States (Akron, Ohio) (Delzell Monson, 1982). Included in the analysis were 327 workers who were employed for at least two years in the plant between 1 January 1940 and 1 July 1971, and who had worked in two departments where acrylonitrile was used, i.e., 81 worked only in the nitrile rubber manufacturing operation where exposures to 1,3-butadiene (see this volume), styrene (lARC, 1994a) and vinylpyridine also occurred and 218 only in the department where the latex was coagulated and dried. [No information on levels of exposure to acrylonitrile was provided ] Mortality among these workers was assessed through 1 July 1978 and compared with age- and calendar-time-specific rates for white men in the United States. SMRs were 0.8 ( = 74 95% CI, 0.7-1.0) for all causes of death, 1.2 ( = 22 95% CI, 0.8-1.9) for all cancers combined, 1.5 ( = 9 95% CI, 0.7-2.9) for lung cancer, 4.0 ( = 2 95% CI, 0.5-14.5) for urinary bladder cancer and 2.3 ( = 4 95% CI, 0.6-5.8) for cancers of the lymphatic and haematopoietic system. SMRs for lung cancer by duration of employment were [1.0] (4 observed, 3.8 expected) [95% CI, 0.3-2.7] for < 5 years, and [3.3] (5 observed, 1.5 expected) [95% CI, 1.1-7.8] for 5-14 years. No case was observed with duration > 15 years. 

Table 10. Eight-hour time-weighted average personal exposures to butadiene in synthetic rubber plants in the European Union (1984-93)...

Occupational exposure to 1,3-butadiene occurs in the production of monomeric 1,3-butadiene and of 1,3-butadiene-based polymers and 1,3-butadiene-derived products. The mean full-shift, time-weighted average exposure levels measured for workers in these industries have usually been below 10 ppm [22 mg/m- ], although that level may be exceeded during some short-term activities. Recent data from monomer extraction and styrene-butadiene rubber plants showed lower average concentrations (< 5 ppm [< 11 mg/m ]). 1,3-Butadiene is not usually found at detectable levels in workplace air during manufacture of finished rubber and plastic products. 

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