THE DEGRADABILITY OF NATURAL RUBBER

( TOY BALLOONS )



A bibliographical review of the scientific literature showing the degradability of toy balloons, which are made of natural rubber, due to the effects of bacteria, light, air, and weathering.




Prepared by:

D. K. Burchette

for:

The Environmental Committee of the
National Association of Balloon Artists


May 22, 1990

Reference 1. Brace Golding, Ph. D.; Polymers and Resins; van Nostrand Publishing; New York; 1959; Page 162:

"(Natural) Rubber is extremely sensitive to decomposition by the action of oxygen, particularly in the presence of light."

Reference 2. W. J. Roff and J. R. Scott; Fibers, Films, Plastics and Rubbers; Butterworths; London; 1971:

"The relatively high protein content of natural rubber (2-3.5%) renders it liable to attack by micro-organisms, even when vulcanized... Vulcanized rubbers deteriorate with passage of time due to oxidation and chain scission in the molecular network." Pg. 313.

"The chemically unsaturated structure of natural rubber renders it liable to oxidation, with consequent deterioration... This occurs in all forms of the material on long keeping in air, and is aggravated by sunlight." Pg. 327.

Reference 3. C. M. Blow; Rubber Technology and Manufacture; Butterworths; London; 1971; Pg. 36:

"Familiar to all is the liability of rubber to perish, to harden and crack or soften to a sticky residue. Natural rubber is particularly sensitive to this respect..."

Reference 4. Anthony Davis; Weathering of Polymers; Applied Science Publishers; London; 1983; Pg. 240:

"The inherent reactivity of the unsaturated groups in diene rubbers (natural rubber) makes them particularly prone to oxidative degradation. Thus in the presence of air... light can cause rapid deterioration. It has also been known for many years that diene rubber (natural rubber) is subject to attack by ozone even at the low concentrations found outdoors."

Reference 5. C. C. Davis; The Chemistry and Technology of Rubbers; ACS Monograph Series; Reinhold; New York; 1937; Pg. 819:

"The gradual perishing of soft vulcanized rubber is universally recognized. This deterioration eventually causes vulcanized rubber compounds to become hard, brittle, or soft and sticky and easily torn... Oxidation and the action of light are important factors in hastening the deterioration."

Reference 6. Harry L. Fisher; Chemistry of Natural and Synthetic Rubbers; Reinhold; New York; 1957; Pg. 49:

"Deterioration of natural rubber... is caused chiefly by action of oxygen and ozone. Light tends to activate these reactions, but oxygen and ozone attack these rubbers even in the dark"

Reference 7. P. K. Freakley, A. R. Payne; Theory and Practice of Engineering With Rubber; Applied Science Publishers LTD; London; 1978; Pg. 12:

"(Natural) Rubber, like many other organic materials is liable to undergo changes with time. The main cause is oxidation by atmospheric oxygen, which may be aggravated by light..."

Reference 8. R. D. Deanin Ph. D.; Polymer Structure, Properties, and Applications; Cahners Books; Boston; 1972;

"The unsaturated double bond in natural rubber.., causes sensitivity to oxygen and ozone (especially when stretched), and this sensitivity is increased by light producing rather poor aging properties."

Reference 9. The Language of Rubber; E. I. DuPont de Nemours & Co.; Wilmington, Delaware; 1957; Pg. 42:

"Exposure of (natural) rubber compositions to weathering and sunlight accelerates the rate at which their physical properties deteriorate... much more rapid in the presence of sunlight. The primary effects noted are attributable to ozone attack and oxidation."