Polyethylene (PVC) Thermal Stability Tester

Evaluating Polymer Durability with the Polyethylene (PVC) Thermal Stability Tester

Introduction
Polyvinyl chloride (PVC) and polyethylene materials must withstand thermal stress during processing and end‑use. The Polyethylene (PVC) Thermal Stability Tester from Changsha Friend Experimental Analysis Instrument Co., Ltd. assesses heat‑ageing resistance by measuring color change, HCl evolution, and molecular‑weight alteration under accelerated conditions.

Testing Principle
Polymer specimens (3 g) in open test tubes are placed in a thermostatted oil bath at 180 °C for defined times (0–6 hours). At intervals, tubes are removed and cooled; the evolved HCl gas is absorbed in a titration solution to quantify dehydrochlorination rate. Simultaneously, specimens’ color is measured using a tristimulus colorimeter, and molecular‑weight distribution is analyzed by GPC if desired.

Technical Design Features

• Precision Oil Bath: Maintains 180 °C ± 0.5 °C with magnetic stirring to ensure uniform heat transfer.

• HCl Collection Module: Gas outlet funnels HCl into an automated titration cell, recording acid number in real time.

• Colorimeter Integration: Mounted atop each test tube for immediate color-difference (ΔE) measurement post‑ageing.

• Time‑Sequenced Sampling: Software schedules tube removal and HCl titration, reducing manual timing errors.

Industry Applications

• PVC Compounders: Screen stabilizer packages for extrusion and injection molding processes.

• Polyethylene Film Producers: Evaluate antioxidant performance under high‑temperature sterilization.

• Additive Manufacturers: Compare phenolic or phosphite antioxidants for optimum thermal protection.

• Quality Control: Verify batch consistency and predict service‑life performance.

Best Practices

1. Specimen Preparation: Mold or extrude uniform test bars (4 mm × 10 mm) to minimize thickness variation.

2. Bath Cleanliness: Replace oil periodically to remove degraded compounds that can affect heat transfer.

3. Titration Validation: Conduct blank runs and use standardized HCl solutions for calibration.

4. Color Measurement: Standardize illuminant and geometry settings to ensure comparable ΔE results.