As an engineering material, the quality and performance of PP Honeycomb must be evaluated through a series of standardized tests. Key tests include:
- Physical Property Tests:
- Density: Measured per standards (e.g., ISO 845) as mass per unit volume, a fundamental parameter.
- Moisture Content: Ensures material is dry, as moisture can affect bonding and processing.
- Mechanical Property Tests (Most Critical):
- Flatwise Compression: Tests core strength and modulus when compressed perpendicular to the panel plane (e.g., ASTM C365). Reflects the core’s ability to support skins and prevent them from approaching each other.
- Shear Properties: Includes in-plane shear (e.g., ASTM C273) and out-of-plane shear (edgewise shear, e.g., ASTM C393). Tests shear strength and shear modulus, core parameters for calculating sandwich panel stiffness.
- Flexural Test of Flat Sandwich Panels: Direct preparation of small sandwich specimens for three- or four-point bending tests (e.g., ASTM C393), directly evaluating the combined performance of core and skins.
- Thermal and Fire Performance Tests:
- Heat Deflection Temperature (HDT): Evaluates heat resistance.
- Flame Retardancy Tests: e.g., UL94 vertical burn, Limiting Oxygen Index (LOI), full EN45545 test suite (ignitability, flame spread, heat release, smoke density, toxicity).
- Environmental Durability Tests:
- Water Boil Test: Specimens are immersed in boiling water for a set time, then tested for mechanical property retention, evaluating resistance to hydrothermal aging.
- Salt Spray Test: Evaluates corrosion resistance (though PP itself is resistant, tests long-term effects).
- Thermal Cycling Test: Evaluates dimensional stability and fatigue resistance.
- Process-Related Tests:
- Surface Wettability: Assessed via contact angle measurement or simple adhesive droplet test, evaluating surface treatment (e.g., corona) effectiveness, crucial for bond quality.
- Resin Uptake: For wet processes, measures resin weight absorbed by a given core area, aiding process control.
When selecting suppliers, request standard test reports from authoritative third-party laboratories to ensure data reliability.
