Modelling the Thermal Degradation and Stabilisation of PVC in a Torque Rheometer

Abstract

A novel method for simulating the torque and temperature curves from a torque rheometer thermal stability test on poly(vinyl chloride) (PVC) was developed. A mathematical model was proposed which combines the chemical kinetics involved in the thermal degradation and stabilisation process of PVC with heat transfer and viscosity relationships within the torque rheometer. The model coefficients were fitted to data obtained from previous experiments with a program written in the Python programming language using the Levenberg-Marquardt Algorithm (LMA) with multiple starts. The mathematical model fits the torque rheometer data successfully depending on the characteristics of the torque curve. The model fit is successful when the torque curve follows the expected behaviour. An unsuccessful model fit occurs when the torque curve deviates from the expected shape in a very specific way. In the degradation phase the torque curve increases to a local maximum, decreases to a local minimum and then increases again. The exact reason for the dip in torque is unknown.

Kinetics of poly(vinyl chloride) thermal and thermo‐mechanical degradation in the presence of epoxidized plasticizer. Induction effect

“…83, pg. 232) 39,40 . Similarly, the rate of degradation was reduced in the presence of acid scavenging ELO.…”

“…The time dependence of torque on masticating blades was used to monitor kinetics of plasticized PVC thermo- 39,40 Similarly, the rate of degradation was reduced in the presence of acid scavenging ELO. Thermomechanical stability of plasticized PVC was very sensitive to the amount of ELO in PVC formulation.…”

The Facile Strategy of Improving the Long-Term Stability of Highly Transparent Polyvinyl Chloride by Introducing Unsaturated Zn Oleate and Uracil Derivatives

“…The dynamic thermal stability of PVC measured by torque rheometer is a way to reflect the rheological properties of the polymer in actual processing [ 32 ]. Figure 9 shows the dynamic thermal stability of PVC with different amounts of ESBO.…”

Bean Dreg–Hydrocalumite Composite as a Highly Efficient Thermal Stabilizer for Poly(vinyl chloride)

“…However, the dynamic thermal stability time decreases to 2082 s with further increase of the Ca/Al molar ratio to 2.4:1. According to the literature, ,− the laminate structure, layer spacing, and intercalation ions could be adjusted by controlling the proportion of metal ions in the laminate of hydrotalcite-like materials so as to affect its performance as a PVC thermal stabilizer.…”