Measurement of aging effects of ABS polymers

Abstract

ABS (acrylonitrile‐butadiene‐styrene) plastics are one of the most common two‐phase commercial polymer systems. They consist of a continuous rigid phase (styrene‐acrylonitrile co‐polymer) in which the elastomer phase (polybutadiene grafted with styrene and acrylonitrile) is finely dispersed in the form of spherical particles. Because of their properties and relatively low cost compared to other engineering thermoplastics, ABS resins are now being used increasingly in fields of application involving severe aging. The polybutadiene content, however, poses a problem in relation to ABS aging resistance, since it is a prime site for degradative attack at double bonds and tertiary carbon atoms. The present paper presents a concise account of the methods used in our labortory for measuring ABS aging. As an example, ABS degradation during processing and during natural and artificial light aging are discussed in more detail.

Influence of temperature and shear rate on the rheology and processability of reprocessed ABS in injection molding process

“…This has been simulated by repeated injection molding, two injection molding cycles have been carried out. Two injection molding cycles have been considered because in industrial applications the materials usually are not reprocessed more than twice due to its mechanical degradation as Casale et al (1975) and Eguiazabal and Nazabal (1990) suggested. The polymer was dried in an air oven before each processing cycle to minimize degradation reactions caused by moisture.…”

“…In another study, Casale et al (1975) evaluated the effects of reprocessing conditions on mechanical properties by varying temperatures and dwell times. In this case material was ground and remolded five times.…”

Solid Freeform Fabrication Proceedings

“…(4) due to the exponential nature of t". The second factor is related to the degradation of ABS by molecular chain breaking, oxidation, and butadiene particle coelescence at the high temperatures used during FD extrusion (Casale et al, 1975;Kelleher, 1966). This temperature related degradation is being confirmed via comparison of the molecular weights and microstructures (i.e., the butadiene particle size distribution) of the bulk ABS with extruded FD-ABS.…”

Influence of flame retardant additives on the processing characteristics and physical properties of ABS

“…Therefore care must be taken during extruder compounding not to leave the ABS in the barrel for excessive periods of time otherwise the polymer could become discoloured [20]. In extreme cases where excessive degradation occurs, brittleness, 'pockets' of degraded polymer or even smoke and fume emission can occur.…”

“…Grafted SAN on the surface of the polybutadiene particles forms a compatible link between the particles and the matrix. By varying the amount of the components, the manner by which they are combined and the size and number of elastomer particles, ABS resins can be manufactured to a wide specification range [20]. This range includes low to high impact, low gloss, glass reinforced, fire retarded, high heat and plating grades to name a few.…”