Why do rubber & plastic surfaces change colour?

Rubber and plastic surfaces may be altered by cracking, developing chalky or dusty surfaces, or becoming sticky. Colour changes may be caused by reactions that change the molecules of the polymers that constitute plastics and rubbers, or by changes in dyes or pigments that accompany general deterioration.

Does photodegraded rubber increase carbonyl index?

The result and trend observed are in good agreement with the spectroscopic characterization of the rubber, where photodegraded samples recorded a higher increase in the relative amount of -OH and C–O–C groups, as well as a good increase in carbonyl index.

Does outdoor photo treatment affect the degradation of PDA-compounded rubber?

PDA-compounded rubber that was subjected to outdoor photo treatment experienced more severe degradation compared to the thermally treated PDA-compounded rubber, evidenced by more significant increase in surface hydrophilicity and lower decompostion temperature.

Why is the photodegradation of rubber a progressive reaction?

Furthermore, the photodegradation of the rubber is a progressive reaction, with the rate of degradation expected to remain high during the entire process due to the formation of the carbonyl group which is known to strongly absorb radiation in the UV region [ 37, 38, 39 ].

What causes rubber & plastic to deteriorate?

The primary agents that cause rubber and plastics to deteriorate are radiation, high humidity, high temperature, oxygen and pollutant gases, and stress and other direct physical forces. However, not all rubber and plastics are attacked to the same extent by each agent. Exposure to ultraviolet (UV) radiation is damaging.

How does spectroscopic analysis affect the chemical structure of rubber?

Spectroscopic analysis was used to quantify changes in the chemical structure of the rubber, including the formation of carbonyl, hydroxyl, and ether linkages. The changes in the surface hydrophilicity, crystallinity, and thermal properties of the rubber throughout the degradation process were evaluated as well.