ABS (Acrylonitrile Butadiene Styrene co-polymer) is an engineering plastics material which is often used in medical devices applications. The reason resides in its relevant properties like processability, impact resistance, surface appearance or dimensional stability among others. For medical applications, specific ISO10993 biocompatible grades are also available, fulfilling with regulatory compliance while maintaining all advantages of ABS properties, like sterilisation and good chemical resistance.
Most plastics normally derive from petroleum as many other materials, like rubbers, synthetic fibres, resins, paints, coatings, adhesives, dyes, detergents, pesticides etc.. Petroleum is a non-renewable fossil resource that was formed over millions of years through the decomposition of prehistoric plants and animals under high temperature and pressure conditions. From the environmental sustainability perspective, the extraction and use of fossil oils is a relevant cause of global warming (due to the related CO2 emissions) and depletion of fossil reserves.
The good news is that plastics do not need to be necessarily produced starting from petroleum, because nowadays biocircular feedstocks and chemical recycled feedstocks are already proven alternatives. Most important, the recycling technologies that promote the use of such feedstocks are being progressively scaled up. This means, it is possible to continue relying on plastics properties advantages while moving away from fossil raw materials and heading towards sustainable alternatives. The mass balance approach enables this transition, preserving the already existing polymers supply chains while pushing the shift. In this article we will discuss how this is possible mentioning the specific case of ABS plastics. In fact, leading ABS manufacturers are already implementing the two types of sustainable feedstocks previously mentioned.
The petrochemical cracker is a pivotal point for many plastics supply chains. This is an effective stage where the substitutions from fossil-to-bio-circular and from fossil-to-chemical-recycled feedstocks can take place. Crackers are generally designed to process naphtha, which is normally obtained by refining and pretreating crude fossil oil. Nowadays, also bio-circular oils and pyrolisis oils (from chemical recycled waste) can be efficiently refined through methods like hydrotreating and fractional distillation. Once pre-treated, these sustainable oils can be used to feed the cracker, substituting fossil with sustainable naphtha (e.g. bio-naphtha). This input raw material for the cracker is a blend of saturated hydrocarbon chains, containing between 5 and 12 carbon atoms (C5–C12). Such chains need to be broken down by the cracker into smaller and often unsaturated hydrocarbons, producing primary basic molecules that are used in huge quantities in multiple supply chain industries. Approximately 90% of all worldwide plastics production is based on this reduced group of basic molecules. These are: olefins (e.g. ethylene, propylene, butadiene) and aromatics (benzene, toluene, xylene). As consequence, the choice of the cracker as input point of sustainable feedstocks offers huge economy of scales. Hundreds of millions of tons of volumes are produced, feeding different key polymers supply chains.
Let’s consider the cracking process for the The good news is that plastics do not need to be necessarily produced starting from petroleum, because nowadays biocircular feedstocks and chemical recycled feedstocks are already proven alternatives. Most important, the recycling technologies that promote the use of such feedstocks are being progressively scaled up. This means, it is possible to continue relying on plastics properties advantages while moving away from fossil raw materials and heading towards sustainable alternatives. The mass balance approach enables this transition, preserving the already existing polymers supply chains while pushing the shift. In this article we will discuss how this is possible mentioning the specific case of ABS plastics. In fact, leading ABS manufacturers are already implementing the two types of sustainable feedstocks previously mentioned. The petrochemical cracker is a pivotal point for many plastics supply chains. This is an effective stage where the substitutions from fossil-to-bio-circular and from fossil-tospecific supply chain of ABS material. The primary basic output molecules of interest for ABS coming from the cracker are: ethylene, propylene, butadiene and benzene.
The molecules ethylene and benzene are needed to produce ethylbenzene and in a second step styrene, which is one of the three ABS input monomers for the polymerisation process. Butadiene, second input monomer, is needed to polymerise into polybutadiene (the rubber phase contained in ABS, which provides impact resistance properties). Propylene reacts with ammonia (this one obtained from natural gas) to produce acrylonitrile, the third ABS input monomer, and to polymerise with styrene into SAN. SAN (Styrene-Acrylonitrile co-polymer) is the matrix phase of ABS, which provides chemical resistance and stiffness properties to the material. Polybutadiene, chemically grafted with Styrene and Acrylonitrile is already an ABS polymer, with high rubber content. This phase is dispersed in the SAN matrix, completing the ABS polymer formulation.
