SAN is similar in use to
polystyrene. Like polystyrene itself, it is transparent and brittle. The copolymer has a
glass transition temperature greater than 100 °C owing to the
acrylonitrile units in the chain, thus making the material resistant to boiling water. It is structurally related to
ABS plastic, where
polybutadiene is copolymerised with SAN to give a much tougher material. The rubber chains form separate phases which are 10-20 micrometers in diameter. When the product is stressed,
crazing from the particles helps to increase the strength of the polymer. The method of
rubber toughening has been used to strengthen other polymers such as
PMMA and
nylon. Uses include food containers, water bottles, kitchenware, e.g., blenders and mixers, healthcare materials, cosmetic jars, computer products, packaging material, household equipment e.g., shower trays,
battery cases and
plastic optical fibers. ==References==