ABS Resins

Chemical properties

white to off-white powder

Chemical properties

As has already been mentioned, the range of possible ABS polymers is very large since both the ratio of the three monomers and the manner in which they are assembled in the final product can be varied considerably. Thus commercial ABS polymers are available with appreciable differences in properties, but they are generally characterized by high impact strengths and softening points as high as, or higher than, straight polystyrene.
The ABS polymers prepared by grafting contain varying amounts of ungrafted polybutadiene (which has a low glass transition temperature) and therefore have good low-temperature impact strength. Also, the ABS polymers prepared by grafting are superior to those obtained by blending in that moulded specimens commonly have a better surface appearance. In recent years, special grades of ABS polymers have been produced in which a fourth monomer is present. For example, heat-resistant grades contain a-methylstyrene and transparent grades incorporate methyl methacrylate.
ABS polymers can be injection moulded and extruded and have been used in a great variety of applications which require toughness, rigidity and good appearance, e.g. automobile fascia panels and radiator grilles, household appliances, business machines, telephones and pipe and pipe fittings.

The Uses of ABS Resins

Typical Applications Include:

• Semi-con: HDD Components; Wafer Handling; Jigs;Casings; & Connectors
• Industiral: Converying;Metering; and Sensing applications

Production Methods

acrylonitrile-butadiene-styrene resins are commonly referred to as ABS resins. These materials are thermoplastic resins that are produced by grafting styrene and acrylonitrile onto a diene-rubber backbone. The usually preferred substrate is polybutadiene because of its low glasstransition temperature (just above ?80 °C). Where ABS resin is prepared by suspension or mass polymerization methods, stereospecific diene rubber made by solution polymerization is the preferred diene. Otherwise the diene used normally is a high-gel or cross-linked latex made by a “hot-emulsion” process.

Preparation

Two basic processes are used commercially to prepare ABS polymers, namely blending and grafting. These processes give rise to materials which are rather different to each other. Of the two processes, grafting is now the more important.
(a) Blending
The products obtained by this method are mechanical blends of styreneacrylonitrile copolymers and acrylonitrile-butadiene rubbers. The preferred method of preparation is by blending latices of the two copolymers and coagulating the mixture. A wide range of products is possible, depending on the composition of each copolymer and the relative amounts of each employed. A typical blend would consist of the following (solids):
70 parts of styrene-acrylonitrile copolymer (70: 30)
40 parts of acrylonitrile-butadiene rubber (35: 65)
It has been found that non-cross-linked acrylonitrile-butadiene rubbers are compatible with styrene-acrylonitrile copolymers and the mixtures show little improvement in impact strength and have low softening points. However, if the rubber is sufficiently cross-linked so as to be not completely soluble in the copolymer then the mixtures have high impact strengths and high softening points. A convenient method of preparing a suitably crosslinked acrylonitrile-butadiene rubber is to take an emulsion polymerization to high conversion; alternatively, a small amount of divinylbenzene can be added to the emulsion recipe. After the two latices have been mixed, coagulation is brought about by the addition of either an acid or a salt. The resulting crumb is washed, filtered, dried, extruded and chopped into granules.
An alternative method of preparing a blend of the two copolymers is by mixing the solids on a two-roll mill. In this case, a non-cross-linked acrylonitrile-butadiene rubber may be used as starting material. The rubber is firstly cross-linked by milling with a peroxide and then the styrene-acrylonitrile copolymer is added.
The physical nature of these blends does not appear to be the same as that of rubber-modified polystyrenes. When this type of ABS polymer is treated with a solvent such as methyl ethyl ketone the sample swells and only partially breaks up; this indicates that rubber networks permeate the styreneacrylonitrile copolymer matrix. When rubber-modified polystyrenes are treated with a solvent such as toluene, complete disintegration into fine particles occurs.
(b) Grafting
In this method of preparing ABS polymers, acrylonitrile and styrene are polymerized in the presence of a polybutadiene latex. A wide range of products is possible, depending on the relative quantities of reactants.
The reaction is carried out at about 50°C. The solid product is then isolated from the latex.
ABS polymers prepared in this way consist of a continuous matrix of styrene-acrylonitrile copolymer, dispersed particles of polybutadiene and a boundary layer of poly butadiene grafted with acrylonitrile and styrene.

General Description

3DXTech^? ABS is made in the USA using 100% virgin resin and colorants - precision extruded onto 1kg reels (2.2 lbs.). The filament is then vacuum-sealed with desiccant to protect it from moisture.

Advantages

ABS Resins is a strong and durable polymer. It is a chemically resistant resin. It gets easily attacked by polar solvents. It offers greater impact properties and slightly higher heat distortion temperature than HIPS.
It has a low melting temperature making it suitable for processing by 3D printing on an FDM machine.
ABS shows excellent mechanical properties. It is hard and tough in nature and thus delivers good impact strength. It offers a high degree of surface quality. Apart from these characteristics, Acrylonitrile Butadiene Styrene exhibits good electrical insulating properties.
It is an ideal material of choice for various structural applications. This is because of its several physical properties such as:
High rigidity, good weldability, and insulating properties; Good impact resistance, even at low temperatures; Good abrasion and strain resistance; High dimensional stability (Mechanically strong and stable over time); High surface brightness and excellent surface aspect