40-year study finds silicone sealants outperform alternatives in long-term weathering

Miami, FL – A 40-year outdoor study conducted in Miami found that silicone sealants maintained strong performance over decades of exposure, outperforming polyurethane and acrylic alternatives across nearly every category examined, according to Momentive.

The study, highlighted by Momentive as part of its “Part of the Solution” series, examined the long-term durability of silicone sealants used in construction. Researchers conducted the testing at the Atlas Weathering Test Site in Miami, Florida, where panels of glass and painted aluminum were mounted outdoors at a 45-degree angle facing south to simulate real-world exposure.

Researchers evaluated the materials for adhesion, flexibility, resilience, toughness and hardness. The silicone products were compared with polyurethane and acrylic sealants, as well as silicone products from five other manufacturers.

Momentive said silicone sealants consistently outperformed polyurethane and acrylic counterparts in nearly every category. Acetoxy silicone demonstrated particularly strong durability, maintaining surface condition and achieving 100% elastic recovery even after decades of outdoor exposure.

The study also examined alkoxy silicone, which cures by releasing neutral methanol. Momentive said the material was compatible with a broader range of surfaces and materials. Although its performance declined slightly during its fourth decade of exposure, it retained strong flexibility and resilience and continued to outperform polyurethane and acrylic alternatives over the long term.

The findings highlight the importance of balancing adhesion with flexibility in construction sealants. According to Momentive, maintaining a strong adhesive bond while allowing a sealant to accommodate structural movement is critical to long-term weatherproofing.

Momentive said its SilPruf weatherseal sealant is designed around those requirements. The 100% silicone paste cures into a durable seal capable of handling high joint movement and prolonged weather exposure.

The company said its silicone sealants have been used on buildings around the world, including the Mira Tower in San Francisco, Central Park Tower in New York, the School of the Art Institute of Chicago, the Shanghai World Financial Center and Pudong International Airport in Shanghai.

Momentive said the combination of long-term durability, strong adhesion, lower volatile organic compound emissions and performance under demanding conditions can help support more resilient and efficient building projects.

The company described the findings as evidence of the long-term performance of silicone-based building sealants and said its silicone technologies are intended to be “Part of the Solution” for construction projects worldwide.