What additives are needed for PC and ABS compounding modification？

December 29, 2025 news

Solving the compatibility between PC and ABS compounding

PC and ABS are partially compatible polymers, and simple blending can easily lead to phase separation, resulting in a decrease in the mechanical properties (especially impact strength) of the alloy. Therefore, compatibilizers are almost indispensable core additives in all PC and ABS compounding formulations.

The modification of PC/ABS alloy is a systematic engineering process that requires the selection of appropriate additives based on the application requirements of the final product. Below, we will provide a detailed list of various additives commonly used in PC/ABS compounding modification and their functions.

1. Core essential additives

Compatibilizer

Function: Improve the interface bonding between PC and ABS, making the phase structure finer and more stable, thereby enhancing the comprehensive mechanical properties of the compound.

Maleic anhydride grafted polymer: the most common and effective type.

Common types:

  • SMA: maleic anhydride styrene copolymer, with significant effects.
  • ABS-g-MAH: grafting maleic anhydride onto ABS chains, with good compatibility with ABS.
  • SEBS-g-MAH: has a dual effect of increasing compatibility and toughening.
  • Acrylic copolymers, such as MBS and ASA, also have a certain degree of compatibilization effect.

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2. Additives for improving processing and stability

Antioxidant

Function: Both PC and ABS are prone to thermal oxidative degradation during high-temperature processing. PC will turn yellow, and its molecular weight will decrease. The butadiene segment in ABS is prone to oxidation.

Common types:

  • Main antioxidant (hindered phenols): such as IrgaNOx 1010, 1076, responsible for capturing free radicals.
  • Auxiliary antioxidants (phosphites), such as Irgafos 168, TNPP, are responsible for decomposing hydrogen peroxide. Usually used in combination with the main antioxidant.

Lubricants/Processing aids

Function: Reduce melt viscosity, improve flowability, prevent melt rupture, reduce adhesion to equipment, and assist in demolding.

Common types:

  • Internal lubricants: such as stearic acid, stearic acid esters (such as GMS), and stearic acid salts (such as calcium stearate). Limited compatibility with polymers, acting as a “ball bearing” internally.
  • External lubricants: such as polyethylene wax (PE wax), oxidized polyethylene wax (OPE wax), and brown coal wax. Migration to the surface of the polymer, forming a lubricating layer between the mold and the melt.
  • Efficient processing aids, such as acrylic polymers (usually core-shell structures), can significantly reduce melt viscosity and improve surface smoothness.

3. Additives for improving mechanical properties

Toughening agent

Function: Although ABS itself has a certain toughening effect on PC, for applications that require extremely high impact resistance (especially at low temperatures), additional toughening agents need to be added.

Common types:

  • MBS resin: It has good transparency and is a commonly used toughening agent for PC/ABS alloys, but its weather resistance is poor.
  • ACR: Acrylic rubber with good weather resistance.
  • Core shell structure elastomers, such as ABS, MBS, ACR, etc., belong to this category and are the most effective toughening methods for engineering plastics.

Enhancer

Function: Improve the rigidity, strength, and heat resistance of polymers.

Common types:

  • Fiberglass: The most commonly used material that greatly improves strength and rigidity, but can cause anisotropy, surface roughness, and equipment wear in the product.
  • Carbon fiber: In addition to reinforcement, it also endows the material with conductivity and electromagnetic shielding properties, resulting in higher costs.
  • Mineral fillers, such as talc powder and wollastonite, mainly improve rigidity and heat resistance, with relatively little effect on impact strength.

4. Additives endowed with special functions

Flame retardant

This is one of the most important application areas of PC/ABS compound, such as electronic and electrical casings.

Function: Make the material reach UL94 V-0, V-1, V-2, and other flame-retardant levels.

Common types:

  • Halogen flame retardants: such as brominated epoxy resins, brominated polycarbonate oligomers, etc. High efficiency, but it has an impact on compatibility and thermal stability, and there is high environmental pressure.
  • Phosphorus-based flame retardants: such as phosphate esters (TPP, RDP, BDP), inorganic phosphorus (red phosphorus). RDP and BDP are the most mainstream halogen-free flame retardants for PC/ABS, with good compatibility with PC and high flame retardant efficiency.
  • Synergistic agents, such as antimony trioxide, when used in combination with halogenated flame retardants, can significantly improve flame retardant efficiency.

Weathering agent/Light stabilizer

Function: To prevent yellowing and performance degradation of materials under ultraviolet irradiation. Butadiene in ABS is a weakness in weather resistance.

Common types:

  • UV absorbers: such as benzotriazoles (Tinuvin 329, 326) and triazines. It can strongly absorb ultraviolet rays and convert them into heat energy.
  • Hindered amine light stabilizers: such as Tinuvin 770, Chimassorb 944. Inhibiting the process of photooxidation by capturing free radicals. Usually used in combination with UVA.

Antistatic agent

Function: Reduce material surface resistance, prevent static electricity accumulation, and avoid dust adsorption or electric shock.

Common types:

  • Internal anti-static agents: such as glycerol monostearate and ethoxylated amines. Mixing during processing will slowly migrate to the surface to form a conductive layer. The effect is long-lasting but slow to take effect.
  • Permanent anti-static agents: such as polyether block amides, carbon nanotubes, graphene, etc. By forming a conductive network to resist static electricity, the effect is permanent, but the cost is high and may affect the mechanical properties.

Coloring agent

Function: Give the product various colors.

Common types:

  • Organic pigments: brightly colored.
  • Inorganic pigments: Strong covering power, good weather resistance, and migration resistance.
  • Masterbatch: The most commonly used form of coloring, composed of carrier resin, high-concentration pigments/dyes, and dispersants, is easy to process and disperse.

5. Typical application formula examples

Universal injection grade:

PC/ABS+compatibilizer+antioxidant+lubricant

High impact resistance level:

PC/ABS+compatibilizer+core shell toughening agent (such as MBS)+antioxidant+lubricant

Flame retardant grade (halogen-free):

PC/ABS+phosphorus-based flame retardant (RDP/BDP)+compatibilizer+antioxidant+flame retardant synergist (may be required)+PTFE (anti-drip agent)

Weather resistance level:

PC/ABS+compatibilizer+UV absorber+hindered amine light stabilizer+antioxidant

 

6. Extruder for PC and ABS compounding

  • A certain amount of torque is required. It is recommended to choose the MH series or the MU series.
  • The recommended diameter of the screw is between 35 and 52mm.
  • The variable-frequency twin-screw extruder, combined with a water tank cooling cutting machine, can accomplish this task.