Silicone vs. Neoprene: Material Differences and Comparisons

Silicone rubbers are created by the cross-linking of siloxane (silicone-oxygen short chains). Being essentially mineral in nature makes them quite different from the largely organically sourced natural and synthetic rubbers. They are extremely resistant to chemical reactions and high temperatures (in some cases handling more than 300°C). Silicone rubbers can also be moderately strong, though oftentimes they tear easily. Silicone is available in hydrolysis-catalyzed or mutually reactive two-part chemistries. They are resilient and highly elastic materials, offering a wide range of hardnesses from Shore A 30 near-gels to Shore A 90+ firm rubbers.

Neoprene is a highly resilient and stable synthetic rubber first developed in response to rubber shortages during the First World War. It is manufactured in sheets, as partially vulcanized bulk material for molding, and in the form of closed-cell and open-cell foams. Another common form is latex. Neoprene latex comes from colloidal suspensions of partially vulcanized 𝛂-chloroprene that finds use in coatings (paints, dips, etc.). This form is transformed into fully vulcanized µ-chloroprene by heating.

This article will differentiate silicone vs neoprene in terms of applications, properties, recyclability, and costs.

What is Silicone?

Silicone rubbers are synthetic elastomers that are based on siloxanes. Siloxanes are organosilicon compounds (“–Si–O–Si–O–” backbones) with side “R” chains attached to the silicon atoms. The chemical formula is R2SiO, where R is either a hydrogen atom or an organic radical functional group. Polymerized siloxanes are called silicones or silicone rubbers. The most common form of silicone rubber is polydimethylsiloxane (PDMS). Manufacturers can synthesize a wide variety of siloxanes and polysiloxanes, making silicone rubbers an extensive family with a wide spectrum of property variations.

One differentiator among silicone rubbers is the method by which the cross-linking occurs:

1. A platinum-catalyzed cure (or the addition-catalyzed system) catalyzes the reaction between a hydride-siloxane and a vinyl-functional siloxane with the help of a platinum complex trigger. This cross-links the two polymers using an ethyl group attached between them.
2. The condensation cure systems can have single- or dual-component chemistries. In the single-component type, hydrolysis leaves a hydroxyl or silanol group which condenses with a hydrolyzable complex built into the R-component polymer, curing the elastomer. Two-component systems use a range of organic catalysts to create the cross-links, releasing some byproducts as they do so. Many such silicones release acetic acid as they cure. Others release an alkaline residue and some are neutral. Learn more in our guide on Silicone Rubber.

What is Neoprene?

Neoprene was originally a DuPont™ product name, but today it is used generically. These are synthetic rubbers manufactured through the polymerization of chloroprene. They are chemically known as polychloroprene or, alternatively, as 𝛂- and µ-chloroprene to denote partial and complete vulcanization status. The IUPAC (International Union of Pure and Applied Chemistry) name is 2-chlorobuta-1,3-diene. Figure 1 is an example of neoprene fabric: