Glossary

Ball mill that both spins on its own axis and, simultaneously, rotates about another axis, giving faster grinding action than a conventional mill.

The method of heat sensitizing natural latex, using certain polypropylene glycols, developed in the 1950s by E.G. Cockbain at MRPRA.

Macromolecular material formed by the chemical combination of monomers having either the same or different chemical composition.

Chemical reaction in which the molecules of a monomer are linked together to form large molecules, whose molecular mass is a multiple of the original substances.

Synthetic rubber or resin prepared by the condensation of an organic isocyanate and a polyester or polyether. It has high abrasion resistance, high tear resistance and low hysteresis.

Form of NRL in which the particles possess a positive electrical charge. (In normal NRL the particles have a negative charge.)

Coagulation or destabilization of field latex through bacterial action. Some of the bacteria feed on carbohydrates of the latex and convert them into volatile fatty acids such as formic acid and acetic acid, while some others feed on the proteins of latex and decompose them. The resultant thickening of latex is known as pre-coagulation, premature coagulation, auto coagulation and spontaneous coagulation.

Measure of the degree to which a latex compound pre-vulcanizes (cross links) during storage.

Chemical or bactericidal activity which destroys or deactivates micro-organisms and enhances the colloidal stability of latex. Ammonia is the most popular preservative. Certain other chemicals used along with lower concentration of ammonia are called secondary preservatives.

Process of vulcanizing latex prior to making a product. The prevulcanization may be either partial or complete, with respect to the ultimate level of cure required for the product.

Latex produced by prevulcanization process.

Method of assessing the state of cure of a prevulcanized latex by measuring the relaxed modulus of a ring prepared from a dipped tube of the latex.

Value obtained from the PRM test, normally in units of Kg/cm2.