Multifaceted Evaluation of Plastics: Differences due to PC/ABS Resin Compounding Ratio

Significance of Multifaceted Evaluation of PC/ABS Blends

In industrial polymer processing, precise control of resin composition is critical to ensure desired mechanical, thermal, and aesthetic properties. Polycarbonate/acrylonitrile-butadiene-styrene (PC/ABS) blends combine the strength and heat resistance of PC with the processability of ABS, making them widely used in automotive interiors, electronics, and consumer goods. Accurate prediction and confirmation of compounding ratios after injection molding improves product quality and process efficiency.

Study Objectives and Overview

This study aimed to establish linear relationships between PC/ABS blend ratio and various material properties, to enable rapid prediction of composition in molded parts. Five PC/ABS ratios (0:100, 25:75, 50:50, 75:25, 100:0) were prepared by controlled kneading and injection molding. Multifaceted characterization techniques were applied to evaluate color, hardness, mechanical strength, thermal transitions, chemical composition, and microscopic phase distribution.

Applied Instrumentation

The following instruments were used:

• UV-2600i UV-VIS Spectrophotometer with integrating sphere
• DUH™-210 Dynamic Ultra Micro Hardness Tester
• AGX™-V Autograph Precision Universal Testing Machine with TRViewX extensometer
• DSC-60 Plus Differential Scanning Calorimeter
• IRTracer™-100 Fourier Transform Infrared Spectrophotometer with QATR™10 accessory
• SPM-Nanoa™ Scanning Probe Microscope/Atomic Force Microscope in Nano 3D Mapping Fast mode

Methodology

Test specimens were molded under standardized kneading and injection conditions for each PC/ABS ratio. Analyses included:

• Yellowness index from UV-VIS reflectance (380–780 nm)
• Microhardness via load-unload indentation (500 mN)
• Tensile properties: strength, elastic modulus, elongation
• Thermal transitions (Tg1 for ABS, Tg2 for PC) by DSC at 20 °C/min under nitrogen
• Chemical composition by FTIR peak intensity at 1770 cm⁻¹
• Surface phase mapping by AFM hardness imaging over 5 µm×5 µm fields

Main Results and Discussion

• Reflectance decreased and yellowness index increased linearly with ABS content, enabling color-based ratio estimation.
• Indentation hardness rose with PC content up to 75 %, but plateaued at 100 % PC, indicating non-linear factors in microhardness.
• Tensile strength and elongation increased proportionally with PC fraction; elastic modulus peaked at 50–75 % PC.
• DSC revealed two distinct glass transitions for ABS and PC; both Tg values shifted linearly with composition, supporting thermal prediction of blend ratio.
• FTIR peak intensity at 1770 cm⁻¹ correlated strongly with PC percentage, confirming chemical composition after molding.
• AFM hardness maps visualized phase distribution consistent with nominal ratios; PC domains appeared as lighter regions occupying the expected volume fraction.

Benefits and Practical Applications

Multifaceted evaluation enables:

• Rapid prediction of composition in finished parts by spectroscopy or mechanical testing.
• Reduction of quality control errors through orthogonal measurement criteria.
• Real-time process adjustments in injection molding to maintain target material properties.

Future Trends and Potential Uses

Emerging directions include:

• Integration of in-line spectroscopic and mechanical sensors for continuous monitoring.
• Advanced image analysis to link microscopic morphology with macroscopic performance.
• Machine learning models trained on multifaceted data for predictive process control.
• Extension of this approach to novel blends, nanocomposites, and sustainable polymer systems.

Conclusion

The combined use of UV-VIS, microhardness, tensile testing, DSC, FTIR, and AFM provides a robust framework to confirm and predict PC/ABS blend composition after molding. Multifaceted evaluation enhances quality assurance, streamlines process control, and supports the development of reliable polymer products.

References

Kawahara K, Yano F, Nishimura T, Hirade M, Ohta M. Multifaceted Evaluation of Plastics: Differences due to PC/ABS Resin Compounding Ratio. Shimadzu Application Note. First Edition: Oct. 2023.