Interfacial Micro-Damping in Mechanically Layered Polycarbonate and ABS

Civilizational assumption under test

Mechanical durability and fatigue resistance in polycarbonate/ABS systems are governed primarily by bulk blending ratios and chemical compatibilization, rather than by physical interface structure.

Why this assumption is load-bearing

Polycarbonate/ABS systems are widely used in automotive interiors, consumer electronics housings, safety equipment, and structural enclosures. Design decisions emphasize blend optimization for impact toughness and processability, with fatigue performance treated as a secondary bulk property.

If interface-driven mechanical dissipation is ignored, designers are constrained to chemistry-based solutions that increase cost, reduce recyclability, and complicate long-term durability prediction.

Edge of Practice experiment

Fabricate mechanically layered, unblended bilayer specimens consisting of polycarbonate bonded directly to acrylonitrile butadiene styrene. No chemical compatibilizers, adhesives, or fillers are permitted.

Bonding may be achieved by co-extrusion, thermal pressing, or controlled melt fusion sufficient to prevent immediate delamination under handling.

Hypothesis

The compliance mismatch between polycarbonate and ABS generates controlled interfacial micro-damping under cyclic mechanical loading. This interface dissipates mechanical energy, slowing fatigue crack initiation and propagation relative to either material alone.

Minimal test protocol

• Specimen: Laminated bilayer sheet (e.g., 1 mm PC + 1 mm ABS)
• Control samples: Monolithic PC and monolithic ABS sheets of equal thickness
• Mechanical loading: Cyclic three-point bend fatigue (≥10⁵ cycles at moderate amplitude)
• Duration: Continuous or intermittent cycling over one week
• Measurements: Crack initiation, crack propagation rate, interfacial integrity, and energy dissipation via DMA

Failure condition

The assumption fails if any of the following are observed:

• Visible interfacial delamination prior to fatigue failure
• Through-thickness crack propagation occurring in fewer cycles than either neat PC or neat ABS
• No measurable increase in mechanical energy dissipation relative to monolithic controls

What breaks if this assumption is false

Mechanical interface effects remain secondary to bulk composition, reinforcing reliance on chemical compatibilization and blend tuning for fatigue resistance.

What breaks if this assumption is true

A purely physical pathway for improving fatigue resistance through mechanical layering becomes viable, challenging blend-centric design paradigms and opening new approaches to durability without chemistry changes.

Status: Final · Immutable