Degradation plastic surfaces

The effects of UV radiation on degradable plastics are usually confined to the exposed surface layers. Tlie general effect is one of embrittlement. Tensile strength may either increase or decrease, but the elongation upon breaking is always reduced. A loss of impact... 

The plastic surface, at the time of bonding, may be well suited to the adhesive process. However, after aging, undesirable surface conditions may present themselves at the interface, displace the adhesive, and result in bond failure. These weak boundary layers could come from the environment or from within the plastic substrate itself. Plasticizer migration and degradation of the interface through uv radiation are common examples of weak boundary layers that can develop with time at the interface. 

The degradation of surface appearance is generally connected with wear, but in the case of textiles it has also secondary effects like "fluffing" and "pilling". In plastics the surface appearance is mainly determined by scratching. Scratch hardness is the main parameter. In textiles the coefficient of friction is the main factor. 

Can degrade plastics by utiUsing raw materials as a food source, potentially causing surface staining (Figure 3), pitting and malodours. Plastic material can also provide... 

The presence of bubbles could be due to air alone or moisture, plastic surface agents or volatiles, degradation, or the use of contaminated regrind. With molds such as those used for injection, compression, casting, or reaction injection, air or moisture in the mold cavity will be the culprit. So... 

Corrosive wear is due to the gradual degradation of the plastic surface through oxidation and chain scission. The embrittled layer is removed quickly at the wear interface. Unlike metals, hydrolytically induced corrosive wear is not a problem in plastics. 

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