Stabilizing poly(vinyl chloride) using its blends with poly(methyl methacarylate): pyrolysis GC/MS studies.

Area of Science:

• Polymer Science
• Materials Chemistry
• Chemical Engineering

Background:

• Poly(vinyl chloride) (PVC) is a widely used polymer, but its thermal degradation releases hazardous byproducts like hydrogen chloride (HCl).
• Understanding polymer blend behavior is crucial for developing safer and more stable materials.

Purpose of the Study:

• To investigate the thermal degradation behavior of poly(vinyl chloride) (PVC) and poly(methyl methacrylate) (PMMA) blends.
• To quantify the suppression of harmful pyrolysis products in PVC/PMMA blends.
• To elucidate the stabilization mechanism of PMMA on PVC during thermal decomposition.

Main Methods:

• Solution blending was used to prepare PVC/PMMA binary blends of varying compositions.
• Thermogravimetric analysis (TGA) and pyrolysis studies were conducted on the blends.
• Volatile pyrolysis products were separated and analyzed using gas chromatography-mass spectrometry (GC/MS).

Main Results:

• The presence of PMMA significantly suppressed harmful PVC pyrolysis products, including HCl and aromatic hydrocarbons.
• The most substantial stabilization effect on PVC was observed at 10 wt.% PMMA content.
• An increased amount of cross-linked residue was retained above 500 °C in the presence of PMMA.

Conclusions:

• PMMA acts as an effective stabilizer for PVC during thermal degradation.
• The stabilization mechanism involves the interaction of PMMA-derived radicals with PVC chains, hindering unzipping via a reversible blocking mechanism.
• PVC/PMMA blends offer a promising route to reduce the environmental impact of PVC thermal decomposition.