Embrittlement of polycarbonate

In this paper we discuss (1) small main-chain motions and their effect on the flow processes, (2) the embrittlement of polycarbonate, (3) the formation of microvoids from sample preparation and their effect on the brittleness of polymer glasses, and (4) the modification of the degree of brittleness of polymer glasses at the filler interface in polymer composites. 

Polybutadiene-PMMA (80 20) core-shell particles of 0.18 pm diameter have been shown to reduce the rate of embrittlement of polycarbonate degraded by physical ageing just below the glass transition temperature [132]. The unmodified polycarbonate became brittle (as assessed by 80% of specimens showing brittle fracture) after 5 h at 135 °C in air, whereas a blend containing 10 wt% of the core-shell particles withstood these conditions for 800 h before embrittlement. By using more thermally stable particles with a poly(n-butyl acrylate) core, embrittlement was further delayed to times greater than 4500 h,... 

The UV technology alluded to above holds out the promise of even more superior labels. In this process, ultraviolet cured inks are used as the printing medium. These are cured by exposure to industrial type UV mercury vapor lamps in either a non-inert system (air environment) or in an inert (oxygen-free) system. The result is excellent adhesion to vinyls, polyesters, polycarbonates, butyrates and acetates and a cured elongation of between 20 and 40% to avoid embrittlement of the substrate. Initial testing has exhibited little sign of degradation and excellent chemical resistance after three years of exterior exposure. Such UV labels as well as other techniques should be considered whenever use demands extended label performance. 

Loss of plasticiser over time leads to embrittlement and component failure, adversely affecting adjacent plastic components, notably those made of polystyrene, ABS or polycarbonate. 

Polycarbonate is characterized by stability to mineral and organic acids. It is also stable in the presence of water. However, if a part—exposed to a hot water or moist high-temperature environment—is loaded in tension, crazing may be encountered. Embrittlement on long exposure also results. For these reasons a top temperature... 

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