Development and Characterization of Conductive Plastisol

Overview

Dip molded and cast PVC Plastisol industrial closures are often used to protect sensitive electrical components during manufacturing and shipping due to their inherent material flexibility, impact absorption, and low-cost manufacturing advantages. Plastisols and most plastic materials, however, inherently store electrical charges which can discharge into the electrical components, causing extensive damage.

Objectives

The overall goal of this project was to develop a material consisting of PVC plastisol and a conductive additive to garner a volume electrical resistivity of or below 1∙10⁵ Ω∙cm.

Approach

• Blends of PVC Plastisol and conductive additives were fabricated in by-weight contents between 0.5 and 10%
• Initial resistivity testing was done on samples to determine viable additives
• Resistivity testing showed carbon nanotubes to be the only additive with potential from initial candidates
• Focused on carbon nanotubes from this point forward, fabricated blends between 0.5 and 7% by-weight carbon nanotube content
• Tested viscosity with a rotational rheometer to confirm viability for dip moulding (100 to 0.1 Pa*s)
• Resistivity tested carbon nanotube samples to find percolation threshold and verify hypothesis
• Samples also sent to carbon nanotube manufacturer for resistivity testing
• SEM imaging done to view additive dispersion and air bubbles

Outcomes

• Percolation found to be at 2% carbon nanotube content
• All resistivity tested blends deemed viable for processing
• Hypothesis met at 5% by-weight carbon nanotube content
• All blends between 1 and 5% are still applicable for anti-static use