Crosslinking of Biocatalytically Synthesized Organosilicone Copolymers for Flame Retardant Applications

Abstract

Crosslinking of polymers using crosslinking agents has been widely utilized to further improve the mechanical and thermal properties of the polymers. We have explored various aliphatic and aromatic dicarboxylic acids such as malonic acid, glutaric acid, isophthalic acid, terephthalic acid and terephthaloyl chloride as crosslinking agents to crosslink polydimethylsiloxane copolymer [poly{poly(dimethylsiloxane-1000)-propylamine-5-aminoisophthaloyl}] to improve its flame retardant properties. We have also used nanoclays [Cloisite 20A, 2C₁₈ MMT (dimethylditallowammonium-/ dimethyldioctadecylammonium-modified montmorillonite)] along with the crosslinker during crosslinking process to further reduce the flammability of the crosslinked polymers. Among all the crosslinkers investigated, isophthalic acid with the nanoclay was found to have the best performance for flame retardant applications. The present work provides a basis to further improve the performance of silicone-based polymers for the flame retardant applications.

Keywords:

• Novozyme-435
• Candida antarctica Lipase B
• organosilicone co-polymers
• flame retardant polymers
• crosslinked polymers
• nanoclay
• thermogravimetric analysis (TGA)
• pyrolysis-combustion flow calorimetry (PCFC)

Acknowledgment

We thank the University of Massachusetts, Lowell (USA) and the University of Delhi under the DU-DST Purse Grant for the financial support for this work. Authors thank Novozyme, Denmark for the enzyme Novozyme-435. Dr. Ravi Mosurkal thanks National Research Council for a senior research associateship at NSRDEC.