Abstract: An article intended to be degraded when exposed to the environment is made from a brittle resinous or synthetic resin material incorporating moisture swellable particles as a filler, whereby exposure of the article to water induces fragmentation. In particular, hydrodegradable "clay pigeons" for shot-gun shooting may be made from a mixture of pitch, powdered limestone or chalk and dry potato starch. Exposure of such a "clay pigeon" or fragments thereof, to water causes swelling of the starch particles and consequent fragmentation of material into, eventually, a fine sludge which is ultimately absorbed into the ground.

Abstract: A degradable polymer composition is disclosed which comprises a blend of a normally stable chemically saturated polymer, such as polyethylene, a less stable chemically unsaturated polymer or copolymer, such as a styrene/butadiene block copolymer, or natural rubber, an antioxidant active over a limited period and a latent pro-oxidant, such as an organic salt of a transition metal, e.g. cobalt naphthenate. The presence together of the anti-oxidant and the pro-oxidant give rise to a period of induction before a sharp loss of physical strength occurs, whereby the period of induction can be exploited as the effective working life of the polymer composition.

Abstract: A degradable polymer composition is disclosed which comprises a blend of a normally stable chemically saturated polymer, such as polyethylene, a less stable chemically unsaturated polymer or copolymer, such as a styrene/butadiene block copolymer, or natural rubber, an antioxidant active over a limited period and a latent pro-oxidant, such as an organic salt of a transition metal, e.g. cobalt naphthenate. The presence together of the anti-oxidant and the pro-oxidant give rise to a period of induction before a sharp loss of physical strength occurs, whereby the period of induction can be exploited as the effective working life of the polymer composition.