For previous reading, please refer to Plastics Materials (Part 5): In-depth Analysis of PP-LGF.
ABS (Acrylonitrile-Butadiene-Styrene copolymer) is one of the most widely used engineering plastics, hailed as a model of "engineering general-purpose plastics and general-purpose engineering plastics." It cleverly combines advantages of three monomers: acrylonitrile provides chemical resistance and surface hardness, butadiene provides toughness and impact resistance, and styrene provides rigidity, processability, and gloss.
With its comprehensive advantages of balanced rigidity and toughness, ease of processing, good surface quality, electroplating capability, easy painting, ABS occupies an irreplaceable position in home appliances, automobiles, electronics, toys, building materials, and other fields.

 

ABS = A (Acrylonitrile) + B (Butadiene) + S (Styrene), a terpolymer, is a typical two-phase structure:

 

Core characteristics of ABS: two-phase structure + balanced rigidity and toughness. Rubber particles are dispersed in SAN matrix. Upon impact, rubber particles induce crazing and shear bands, absorbing a large amount of energy, thereby significantly improving toughness.
Three-Phase Structure and Toughening Mechanism of ABS

 

ABS Toughening Mechanism: Under external force, stress concentration occurs around rubber particles → triggering numerous crazes and shear bands. Expansion of crazes and shear bands consumes a large amount of energy → significantly improving material toughness. Rubber particles simultaneously prevent crack propagation → avoiding brittle fracture.
Main Classifications of ABS

 

Selection Logic: Choose high heat resistance grade if heat resistance is insufficient, choose high impact resistance grade if impact resistance is insufficient, choose high flowability grade if molding is difficult, choose flame retardant grade if fire resistance is required.
ABS vs PP vs PC: How to Choose?

Mechanical properties of ABS can be adjusted over a wide range by changing proportions of three monomers and structure of rubber phase.
Comparison of Typical Properties of Different Types of ABS

Note: Above are typical ranges for materials of same grade. Specific values vary depending on rubber particle size, rubber content, molecular weight, and AN content.
Yield-to-tensile strength ratio analysis
Yield-to-tensile strength ratio (yield strength / tensile strength) of ABS has following characteristics: General grade: High yield-to-tensile strength ratio (~0.85~0.9), with some plastic deformation after yielding. High-impact grade: Low yield-to-tensile strength ratio (~0.75~0.85), strong plastic deformation capacity, and good toughness. High-heat-resistant grade: High yield-to-tensile strength ratio (~0.9~0.95), close to brittle fracture. Engineering conclusion: ABS is a "quasi-tough" material—it has a clear yield point and plastic deformation, but its elongation at break is not very high (10~50%). High-impact grade ABS has the best toughness, while high-heat-resistant grade ABS is more brittle.
Effect of Temperature on Performance
ABS properties are highly sensitive to temperature: Impact Strength: Decreases significantly with decreasing temperature; at -30℃, impact strength may only be 1/3 to 1/2 of that at room temperature. Stiffness: Decreases with increasing temperature; above 80℃, modulus decreases significantly. Dimensional Stability: Low heat distortion temperature (85~110℃), limited high-temperature load-bearing capacity.
Molding Process: Primarily Injection Molding
ABS has excellent processability and is one of the easiest engineering plastics to injection mold.

Other Molding Methods for ABS: Extrusion: Sheets, pipes, profiles. Blow Molding: Bottles, hollow products. Vacuum Molding: Refrigerator liners, suitcases. 3D Printing: Commonly used material in FDM. Electroplating: Preferred material for plastic electroplating.
Ranked by Performance Grade from General Purpose to High Heat Resistance
General Purpose Grade: GP22 is one of the most classic general purpose ABS grades. It has good flowability (MFR 22), is suitable for mass injection molding, and is "benchmark material" for ABS.
High Impact Resistance / Balanced Performance Grade: Magnum series is a bulk-process ABS from Dow Chemical (now Trinseo), known for its color stability, low volatility, and ease of processing. HR-527A is a heat-resistant ABS from Kingfa Science & Technology, offering balanced performance and widely used in automotive interiors.
High Rigidity / High Heat Resistance Grade: HH-106 is a representative of high heat-resistant ABS, with a Vicat softening temperature exceeding 106℃, 10-15℃ higher than general-purpose ABS, making it suitable for automotive interiors and electronic components requiring heat resistance.

ABS is one of the most widely used engineering plastics, penetrating almost all industries.
Automotive Applications

 

Trends in automotive ABS: low VOC, low odor, paint-free, scratch-resistant, and improved heat resistance. With increasing popularity of PC/ABS alloys, pure ABS has decreased in high-end models, but it is still widely used in mid-to-low-end models and non-critical components.
Home Appliance Applications

 

Electronic Appliance Applications

Other Applications

ABS simulation modeling is relatively simple, as it is an isotropic elasto-plastic material.
Five Commonly Used Constitutive Models

 

Three Key Points of ABS Simulation: Isotropy: ABS is an isotropic material (non-filled grade), so fiber orientation does not need to be considered, making modeling simple. Rate Dependence: Impact performance of ABS is sensitive to strain rate; collision simulations need to consider rate-dependent constitutive models. Temperature Sensitivity: Performance of ABS varies significantly with temperature; simulations in high-temperature environments must consider effect of temperature on modulus and strength.
ABS failure modes have unique characteristics, especially stress cracking and aging issues, which require special attention.
Stress Cracking

 

Problem: Under combined action of stress and chemical media, ABS products develop cracks or even fracture. This is one of the most typical failure modes of ABS.
Common Scenarios: Cracking after contact with chemicals such as alcohol, detergents, and lubricants; long-term cracking caused by assembly stress.
How to solve:

Impact Fracture
Problem: Fracture under impact load. ABS has good impact toughness, but it will still fail under low temperature or high impact energy.
Common Scenarios: Drop collision, low-temperature impact, stone impact.
How to solve:

Heat Deformation / High Temperature Failure
Problem: Deformation and strength reduction under high temperature conditions. ABS has relatively low heat resistance, with an HDT of only 85~110℃.
Common Scenarios: Car interior exposed to direct sunlight, high temperatures near headlight housings, heat generation from electronic components.
How to solve:

Development Trends
Low VOC/Low Odor ABS: Meets environmental protection requirements for automotive interiors, reducing volatile organic compounds. Paint-Free ABS: Special color powders and pearlescent effects replace painting, reducing costs and protecting environment. High Heat Resistance ABS: Heat resistance levels are continuously improving, some approaching PC/ABS levels. Flame Retardant ABS: Halogen-free flame retardant, high flow, high heat resistance and flame retardancy. Bio-Based ABS: Some raw materials are bio-based, making it more environmentally friendly. ABS Alloys: Alloying PC/ABS, ABS/PBT, ABS/PA, etc., expanding performance boundaries. 3D Printing ABS: Low warpage, high strength ABS specifically for 3D printing. Recycled ABS: Improved quality of recycled ABS, increased closed-loop recycling. Antibacterial ABS: Added antibacterial agents, used in medical and food contact fields.