Acrylonitrile-C8H8,Butadiene-C4H6, Styrene-C3H3N (ABS) is a thermoplastic this is derived by the combination of three different monomer, as seen above. Each monomer component, however, contains different properties and sources and hence, contributes to the polymer in different ways.
Acrylonitrile is manufactured from propylene and ammonia. Butadiene is a by-product generated from the production ethylene via steam crackers and Styrene is made from the dehydrogenation of ethylbenzene.
To create this terpolymer, it undergoes an emulsification process where the three monomer products are combined to form one product or a patent process known as continuous mass polymerization.
In ABS, the propylene and ammonia components from the acrylonitrile monomer, contributes to the chemical resistance and heat stability of ABS while butadiene and styrene contributes to toughness and impact strength and rigidity, processability and glossy finish, respectively. In its natural form, ABS is an opaque material that is beige or tan in colour. Because of its opaqueness, it can be easily coloured with pigments or dyes.
Some key features of ABS which makes this thermoplastic suitable for LEGOs are its hardness, toughness, rigidity, durability, strength and good chemical and impact resistance.
It is also has very good resistance to diluted acids and alkalis, moderate resistance to aliphatic hydrocarbons, however, it has a poor resistance to aromatic hydrocarbons, halogenated hydrocarbons and alcohols.
RENEWABILITY / END-OF-LIFE CONCERNS
ABS plastics can be recycled like any other plastic, by taking its waste and converting it into various new objects. Recycling of ABS is essential, especially in the 3D printing business, where a lot of waste plastics are generated. One possibility is to reuse discarded 3D prints to create more 3D printing filaments, that is, making ABS plastic from other sources of ABS.
While recyclability of ABS plastics is a great advantage, it is not found to be very environmentally friendly as it cannot be degraded and cannot be renewed.
The production of ABS plastics is one thing, however, the destruction or end of life of these same plastics and its resulting effects is another. Even though, ABS plastics are known for their high heat resistance, on contact with extremely high temperatures, the probability of combustion is very likely. The occurrence of this, causes the organic materials in ABS to be broken down, producing toxic substances such as carbon monoxide and hydrogen cyanide. Therefore, the use of ABS in the food industry is recommended to be limited as it can causes these toxic components to be leached into foods. In addition, lengthy exposure to sunlight can cause damage to ABS materials.
Pyrolysis (decomposition by high temperatures) of plastics in little to no oxygen, allows for the breakdown of long polymer chains into smaller ones, producing a petroleum-like oil.