Buyers comparing ABS with ordinary plastic are usually comparing a purpose-built engineering terpolymer against commodity resins such as polyethylene, polypropylene, polyvinyl chloride and polystyrene. The two groups are not interchangeable in most applications, and the gap is explained by composition first and performance second. ABS is built from three monomers that are polymerised together, so it combines stiffness, toughness and surface quality in one material, while a commodity resin is built from a single monomer and is optimised for one or two dominant properties at a low price per kilogram.
What Ordinary Plastic Means in Procurement
Ordinary or commodity plastic is a collective term rather than a single material. It covers the high volume polymers produced from simple monomers: polyethylene in low density and high density forms, polypropylene, polyvinyl chloride, polystyrene and polyethylene terephthalate. Each of these has a comparatively simple, well understood structure, a mature global supply base and a price that tracks the monomer and energy markets closely. Their properties differ widely among themselves, so the term describes an economic class of material, not a fixed set of specifications.
Composition and Structure: Terpolymer Against Single Monomer Polymers
ABS is a terpolymer of acrylonitrile, butadiene and styrene. In commercial grades, a styrene-acrylonitrile copolymer forms the continuous matrix while polybutadiene rubber is dispersed through it as grafted rubber particles. Typical composition ranges are roughly 15 to 35 percent acrylonitrile, 5 to 30 percent butadiene and 40 to 60 percent styrene, and the ratio of the three monomers is the main lever used by producers to trade flow, gloss and impact strength against each other.
Acrylonitrile: contributes chemical resistance, rigidity and heat resistance
Butadiene: supplies rubbery toughness and low temperature impact strength
Styrene: gives easy processing, gloss and dimensional stability
Structure: ABS is amorphous, whereas polyethylene and polypropylene are semi-crystalline
Relevant material standards: ISO 2580 for ABS moulding and extrusion materials, ISO 1872 for polyethylene, ISO 19069 for polypropylene, ISO 1622 for polystyrene and ISO 1163 for unplasticised PVC
Mechanical and Thermal Performance Comparison
| Property | ABS | Commodity resins, typical |
|---|---|---|
| Structure | Amorphous terpolymer with rubber phase | Single monomer, often semi-crystalline |
| Density | 1.04 to 1.06 g/cm3 | 0.90 to 0.96 g/cm3 for PE and PP; higher for PVC and PET |
| Notched impact strength | High; commonly two to three times commodity PS or PVC | Low for PS; moderate for PP; high for HDPE but with lower stiffness |
| Tensile strength | About 40 to 50 MPa | About 20 to 35 MPa for PE and PP |
| Heat deflection temperature at 1.82 MPa | About 80 to 95 °C | About 45 to 60 °C for PE; about 55 to 70 °C for PP |
| Long term service temperature | Commonly quoted at 60 to 80 °C | Lower for PE; PP can approach similar levels |
| Moulding shrinkage | About 0.4 to 0.7 percent | Up to 1.5 to 2.5 percent for crystalline PE and PP |
| Surface finish | High gloss, easy to decorate, plate and paint | Lower gloss, waxy feel for polyolefins |
Mechanical testing for both families follows the same international methods, which makes comparison straightforward: ISO 527 for tensile properties, ISO 179 and ISO 180 for Charpy and Izod impact, ISO 75 for heat deflection temperature, ISO 306 for Vicat softening, ISO 1183 for density and ISO 1133 for melt flow rate.
Chemical Resistance, Weathering and Flammability
ABS performs well against dilute acids, alkalis, alcohols and mineral oils, but it is attacked by ketones, esters, aromatics and chlorinated solvents; acetone or dichloromethane will dissolve or stress crack a moulded part. Polyethylene and polypropylene are notably more resistant to solvents and to most acids and bases, and PVC also resists acids well, so chemical exposure often favours a commodity resin even where ABS would win on toughness. Weathering behaves in the opposite way: the butadiene phase in ABS contains unsaturated bonds that degrade under ultraviolet light, so outdoor grades need UV stabilisers or a protective cap layer, while stabilised polyolefins are more forgiving outdoors. On flammability, standard ABS grades typically achieve a horizontal burn rating, and flame retardant ABS compounds are available for enclosures that must meet stricter vertical burn requirements.
Processing, Tooling and Cost Considerations
Drying: ABS picks up moisture and must be dried before moulding, typically in a dehumidifying dryer, while polyolefins usually need no drying
Processing window: ABS is normally injection moulded in roughly the 200 to 250 °C range, with good flow and low warpage thanks to its amorphous structure
Shrinkage and tooling: low, uniform shrinkage in ABS allows tight tolerances and complex parts, whereas crystalline polyolefins need generous shrinkage allowances
Secondary operations: ABS accepts solvent welding, electroplating, hot stamping and painting readily; polyolefins generally need surface pre-treatment
Cost: ABS sits well above commodity polyolefins per kilogram, because three monomers, a rubber grafting stage and a multi-step compounding route are involved
When to Choose ABS and When to Choose a Commodity Resin
ABS is the better answer when a part must survive impact, hold tolerance, look good and accept decoration: automotive interior trim such as dashboard components and door panels, appliance housings, power tool bodies, computer and phone casings, keyboards, printer shells, pipe fittings and durable toys. A commodity resin is the better answer for high volume, cost sensitive items where one property dominates: packaging film and bags, blow moulded bottles, pipes and profiles, insulation, disposable containers, caps and closures, and general household articles. ABS is also recyclable by regrinding, but repeated thermal history degrades the butadiene phase, so regrind ratios are normally capped and monitored; flame retardant, plating and painted grades need separate collection streams.
FAQ: ABS and Commodity Plastics
Q: What exactly does ABS stand for?
Acrylonitrile butadiene styrene, a terpolymer in which a styrene-acrylonitrile matrix is toughened by dispersed polybutadiene rubber particles.
Q: Is ABS stronger than ordinary plastic?
Compared with polystyrene it is far tougher, and it is typically two to three times better in impact than the grades of commodity plastic it usually replaces, while also offering better gloss and dimensional stability.
Q: Why can ABS be dissolved by solvents that PE resists?
ABS is amorphous and polar, so ketones, esters and chlorinated solvents penetrate it easily, whereas semi-crystalline, non-polar polyolefins resist those solvents.
Q: Can ABS be used outdoors?
Only with UV stabilised grades or a protective coating, because the unsaturated butadiene phase degrades under sunlight and causes chalking and colour shift.
Q: Which material is cheaper per kilogram?
Commodity polyethylene and polypropylene are cheaper, since ABS requires three monomers as well as rubber grafting and compounding steps.
Q: Does ABS require drying before moulding?
Yes. ABS absorbs atmospheric moisture, so it is dried before injection moulding to prevent silver streaks and loss of impact strength, while polyolefins usually do not need drying.