| Low-molecular-weight, monofunctional hindered phenol | 2,6-di-tert-butyl-4-methylphenol (BHT) | Donates hydrogen to peroxy radicals, interrupting the oxidative chain reaction. The resulting phenoxyl radical is relatively stable. | Selected plastics, elastomers, fuels, and lubricant formulations, subject to application-specific requirements. | Check volatility, migration, odor, color, regulatory status, and compatibility with the material and end use. | Where a simple, established antioxidant is suitable and migration or volatility can be managed. |
| Long-chain ester hindered phenol | Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate | Provides phenolic radical-scavenging activity; its long alkyl chain can influence compatibility and retention in polymer formulations. | Polyolefins and other polymer systems where a hydrophobic, polymer-compatible antioxidant is suitable. | Assess solubility, dispersion, migration, processing conditions, and any effects on clarity or surface appearance. | Where compatibility and retention in a nonpolar polymer are important formulation considerations. |
| Multifunctional, high-molecular-weight hindered phenol | Tetrakis[methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate)]methane | Multiple hindered phenolic groups scavenge radicals; the larger molecule is generally selected where lower volatility and persistence are desired. | Polyolefins, engineering plastics, and elastomer compounds, depending on formulation and processing needs. | Review dispersion, processing stability, thermal exposure, and compatibility; confirm performance with application-specific testing. | Where longer-term thermal or oxidative protection and low volatility are priorities. |
| Bis-phenolic hindered phenol | 2,2′-Methylenebis(6-tert-butyl-4-methylphenol) | Two hindered phenolic groups provide radical-scavenging sites that help slow oxidative degradation. | Selected rubber, plastics, and other industrial formulations, depending on compatibility and end-use requirements. | Check solubility, staining or discoloration risk, migration, and suitability for the specific polymer or elastomer. | Where a bis-phenolic structure fits the formulation and its color and compatibility profile is acceptable. |
| Hindered phenol used in a combined stabilizer system | A hindered phenol paired with a secondary antioxidant, such as a phosphite | The phenol scavenges radicals; a phosphite can help decompose hydroperoxides formed during oxidation. Their complementary roles may improve processing stability. | Polyolefins and other polymer systems exposed to melt processing or heat, where the full formulation is evaluated. | Consider processing temperature, moisture sensitivity of the secondary antioxidant, additive interactions, and regulatory requirements. | Where both radical control and hydroperoxide management are needed; validate the combination in the actual formulation. |