Natural Rubber Lining

The use of natural rubber lining is discussed by Saxman (1965), and the chemical resistance of synthetic rubbers by Evans (1963). 

Residual Life of Natural Rubber Lining in a Phosphoric Acid Storage Tank... 

The materials handled in the bins were 20% solids by weight, flow of 2.9 tons of water per hour and 47 gallons/minute of pulp. The size of the material was 100 to plus 325 BSS mesh. Maximum acid concentration was 20% hydrochloric acid. The temperature in the system was 60°C. A 6 mm thick natural rubber lining of shore hardness 50°A was used to protect the equipment against the abrasive environment as well as the corrosion effects of hydrochloric acid. 

Reversion - The softening of vulcanized rubber when it is heated too long or exposed to elevated temperatures. It is a deterioration in physical properties, (extreme reversion may result in tackiness.) This most commonly affects natural rubber linings. 

When there is a relative motion between the corroding liquid and the metal or rubber surface the rate of attack of the damage to the surface is increased. The process is called sweating off with the corrosion product thus exposing the base surface again to corrosion. Otherwise the corrosion product (as a newly formed protective layer) would have prevented or slowed down further corrosion, just as in the case of hypochlorous acid solution on natural rubber lining, where the protective corrosion products exhibit very low cohesion and as such prone to be wiped off by the liquid unlike wet chlorine or hydrochloric acid which form a strong layer of corrosion product well adhered to the rubber surface. 

In the South African mining industry most processes for recovering precious metals, coal, minerals and diamonds are wet methods, involving the suspension of solids in water [1], In the control of such wet abrasive conditions in the pumping of fine particles size slurries, particle size separation in cyclones and in floatation cells, the choice of soft natural rubber lining is the most cost effective. 

This is red lead monoxide, used as in inorganic accelerator for the curing of soft natural rubber lining in an autoclave. High temperature curing leads to blooming of lead film, which is the chemical resistance layer, but impairs bonding with metal. 

Typical applications for soft natural rubber linings include chemical storage tanks to handle phosphoric acid (37%), hydrofluosiUcic acid, alum, chlorides and sulfates of ammonia, cadmium, iron phosphoras and sodium, inorganic salts in gen-... 

Multiply natural rubber linings consist of three layers of rubber soft natural rubber/ hard natural rubber/soft natural rubber. The advantages of these linings are ... 

Hard natural rubber linings have the advantages of ... 

Biolized materials have been used in our cardiac prostheses since 1969. The first application utilized glutaraldehyde treated bovine aortic valves in a Dacron fabric pump termed a "partially biolized heart". Since thick pseudoneointima (PNI) formation and calcification was observed, the Dacron covered surface was replaced with natural tissue material (9). This original totally biolized heart was a sac-type with a flexing element of natural rubber lined on the blood side with aldehyde treated bovine pericardium. The outside case of the device was made from polyurethane. Early in 1973, a calf implanted with this artificial heart lived for a then-remarkable seventeen days (10). Termination of the experiment was caused by a crack in the flexing sac. A passive implant of this device in the aorta did not show any thrombus formation during 5.5 years implantation. 

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