The result depends on the PC:ABS formulation, additives or reinforcement, the grade, test conditions, and whether you measure pellets or a moulded part. Datasheets for unfilled commercial grades alone span roughly 1.10 to 1.15 g/cm³.
This article defines density, explains the range and what moves it, shows how it is specified and measured, and clarifies what density can and cannot tell you about performance.
Key Takeaways
- Density is mass per unit volume; always quote units, test temperature and grade name.
- PC:ABS ratio, flame retardants, glass or mineral fillers and pigments all shift the value.
- A datasheet figure is typical, not an acceptance limit; rely on the TDS and certificate of analysis.
- Density helps weight calculations but does not establish impact, heat or flow performance.
What PC/ABS Density Represents and Its Operating Range
Density is mass divided by volume. Plastics are usually reported in g/cm³ or kg/m³, where 1 g/cm³ = 1000 kg/m³.
Specific gravity (relative density) is a different quantity. It is a unitless ratio of the material's density to that of water, both at 23 °C. Since water is 0.9975 g/cm³ at 23 °C, density in g/cm³ equals SG × 0.9975.
PC/ABS is a two-component alloy, so its density is a derived characteristic of the specific product, not a constant shared by every grade.
Factors That Influence PC/ABS Density in Real-World Operation
Blend ratio. More PC pushes density up, since PC is denser than ABS. But the blend is not a simple average. Composition analysis often follows the Orzan et al. approach, weighting by reciprocal mass fractions (1/ρ = wPC/ρPC + wABS/ρABS). Partial miscibility can still cause small deviations. Take the final value from the grade's datasheet.
Additives and fillers:
- Flame-retardant packages raise density; grade examples sit around 1.18 to 1.19 g/cm³
- Glass fibre raises it further: a 10% glass-filled grade lists 1.22 g/cm³
- Pigments can shift guide values, per Covestro's datasheet notes
- Recycled content varies by feedstock; measured PC/ABS recyclate batches ranged from 1.117 to 1.141 g/cm³
No universal correction per percent of additive exists, so use data for the exact grade.
Moulded part versus pellet. Moisture, voids, thermal history and specimen preparation all move a measured value. ISO 1183-1 notes that density often depends on how the specimen was prepared. PC/ABS also absorbs moisture; Bayblend T65 XF lists 0.2% equilibrium uptake at 23 °C / 50% RH.
PC/ABS Density Range
Datasheets for unfilled grades at 23 °C or similar reference conditions show:
| Grade | Density (g/cm³) | Density (kg/m³) |
|---|---|---|
| Bayblend T45 PG | 1.10 | 1100 |
| Trinseo PULSE A35-105 | 1.12 | 1120 |
| Bayblend T65 XF | 1.13 | 1130 |
| Bayblend T85 XF | 1.14 | 1140 |
| CYCOLOY C1200HF | 1.15 | 1150 |
That 1.10 to 1.15 g/cm³ window is a sample of five grades, not a universal limit. Test methods (ISO 1183 or ASTM D792) and conditioning differ between sheets.
For context, ABS (CYCOLAC MG47) lists 1.04 g/cm³ and unfilled PC (Makrolon 2405) lists 1.20 g/cm³. Flame-retardant PC/ABS grades sit around 1.18 to 1.19, and the 10% glass-filled grade at 1.22.
Keep three ideas distinct: a typical value is the supplier's nominal figure, a tolerance is the expected spread, and an acceptance boundary is a contractual limit. Density is usually a characteristic window, not a safe operating range like temperature or pressure.
Key Technical Properties of PC/ABS Density
Density is one property in a linked system. A higher or lower number is not automatically better.
Stability and Variability
Repeatability depends on lot-to-lot formulation, recycled content, additive dispersion, moisture and processing history. Compare like with like: same grade, specimen type and conditioning.
A density shift can point to a formulation or production difference. Investigate it alongside composition, visual quality, mechanical data and batch documentation before drawing conclusions.
Relationship to Part Weight and Material Use
Mass equals density × volume. A hypothetical example, using Bayblend T65 XF (1.13 g/cm³):
- Assume a CAD volume of 200 cm³ (illustrative only)
- Mass = 1.13 × 200 = 226 g per part
- For 10,000 parts: about 2,260 kg of resin, before sprues, runners and scrap
CAD volume is not the whole story. Wall thickness, ribs, inserts, voids and actual moulded geometry change finished-part weight, so weigh real shots during trials.
Coupling with Adjacent Material Properties
Changing the blend ratio or adding reinforcement alters density together with impact, heat resistance, stiffness, flow, shrinkage and finish. Same-manufacturer SABIC grades show how density alone misleads:
| Grade | Density (g/cm³) | Notched Izod, 23 °C | Vicat B50 |
|---|---|---|---|
| CYCOLAC MG47 (ABS) | 1.04 | 22 kJ/m² | 98 °C |
| CYCOLOY C1200HF (PC/ABS) | 1.15 | 49 kJ/m² | 130 °C |
| LEXAN 141R (PC) | 1.20* | 70 kJ/m² | 141 °C |
*PC density uses Makrolon 2405 (Covestro); confirm the LEXAN 141R figure on the current datasheet. Treat the table as named-grade comparisons, not family-wide rankings. Choose on impact, heat, cost, flow and finish for the application.
How PC/ABS Density Is Specified, Measured, and Validated
Density serves two roles: a datasheet property for selection, and a quality-control check. Either way it is only meaningful under a defined method and specimen condition.
Specification and Documentation
On a TDS, look for:
- Exact grade name and whether it is filled or reinforced
- Density value, units and test temperature
- Conditioning and test standard
- Whether the figure is typical, nominal or lot-tested
TDS values are indicative. SABIC's CS9610 datasheet states its information is for material selection, not a specification. When density is critical, also request the certificate of analysis (which reports actual results and methods), lot identification, formulation-change notices and retained samples.
Measurement and Verification Methods
- ASTM D792: displacement in water (Method A) or other liquids (Method B)
- ISO 1183-1: immersion, liquid pycnometer or titration
- ISO 1183-2: density-gradient column
- ISO 1183-3: gas pycnometer, for specimens without closed pores
D792 calls for at least 40 hours of conditioning at 23 ± 2 °C and 50 ± 10% RH, smooth surfaces, no grease, and removal of trapped air bubbles. Temperature control, moisture, instrument resolution and operator technique all affect accuracy. A controlled lab result is not the same as a quick shop-floor estimate.
Validation and Scale-Up
- Confirm the grade and read its TDS
- Measure a representative sample using the specified method
- Compare against the COA and stated tolerance
- Investigate deviations
- Recheck after moulding if part weight or quality is affected
For manufacturers qualifying or scaling specialty polymer supply, Distil's R&D team runs application-specific trials, and its partner network and production visibility help manage scale-up. This supports evaluating material fit; it is not an accredited density-testing service.
Implications of Operating Outside the Expected Range and Common Misinterpretations
An unexpected density result changes calculated weight and material use. It may also signal the wrong grade, additive or reinforcement variation, inconsistent blending, moisture, voids, or a testing error. Run a root-cause check before rejecting a batch.
Common mistakes:
- Treating one published value as universal
- Assuming higher density means higher strength
- Averaging PC and ABS densities to predict the blend
- Confusing density with specific gravity, or with finished-part mass
Review density alongside impact, tensile, flexural, heat-deflection, melt-flow, shrinkage, chemical-resistance, and flame requirements before you approve a material or supplier.
Conclusion
PC/ABS density is grade-dependent, governed by blend composition, additives, processing and measurement conditions. There is no single number for every alloy.
Reliable decisions need a sourced TDS and COA, consistent measurement, and density values read alongside the properties that drive application performance.
Frequently Asked Questions
What is the density of PC plastic?
Unfilled polycarbonate such as Makrolon 2405 lists about 1.20 g/cm³ (1200 kg/m³) at 23 °C by ISO 1183-1. Pure PC is denser than PC/ABS.
What is the typical density of PC/ABS?
Standard unfilled grades typically range from 1.10 to 1.15 g/cm³. Exact values vary with PC:ABS ratio, additives, reinforcement and supplier grade.
Does the PC:ABS ratio change the density of PC/ABS?
Yes. More PC generally raises density, but the relationship is not a simple average. Check the specific grade's TDS.
How does PC/ABS density compare with ABS and polycarbonate?
Sample grades show ABS near 1.04, PC/ABS at 1.10 to 1.15 and PC near 1.20 g/cm³. Fillers, flame retardants and test methods shift these figures.
How is PC/ABS density measured?
Standards include ASTM D792 and ISO 1183 (parts 1 to 3). Conditioning, temperature, immersion method and void control affect the result.
Which plastic is better, ABS or PC?
Neither universally. ABS offers easier processing, good finish and lower cost; PC offers higher impact and heat performance. PC/ABS balances the trade-offs.
