NU 2020-153

INVENTORS
John Torkelson*
Mohammed Bin Rusayyis

ABSTRACT
Conventional permanently crosslinked polymer networks are used in an array of applications because of their excellent mechanical properties, high heat stability, and outstanding chemical resistance. Unfortunately, their lack of recyclability due to the presence of permanent cross-links results in major economic and sustainability losses. To overcome this issue, research has focused on reprocessable polymer networks which contain dynamic covalent bonds that are capable of dissociating or exchanging in response to external stimuli, rendering them malleable. However, very few studies have reported full crosslink density recovery after reprocessing and most of these studies were focused on step-growth polymer networks and no study has previously reported full cross-link density recovery of reprocessable networks prepared directly from only monomers via addition polymerization.  Northwestern researchers have developed a technology that offers a means to produce reprocessable polymer networks made from only monomers that can be prepared via addition polymerization and exhibit full cross-link density after recycling multiple times. The technology is based on the use of a novel bifunctional crosslinker containing dynamic dialkylamino disulfide linkages which can copolymerized with vinyl monomers via addition polymerization to produce reprocessable polymer networks. The resulting networks also exhibit excellent creep resistance at elevated temperatures which is major problem in reprocessing polymer networks.

APPLICATIONS  

• Automobile parts
• Insulation
• Medical devices
• Self-healing material

ADVANTAGES  

• Allows recyclability/reprocessability of cross-linked polymers (networks)
• Demonstrates full crosslink density recovery after recycling
• Provides a means to produce reprocessable addition-type polymer networks that are prepared only from monomers and still exhibit full crosslink density after recycling
• Offers a simple one-step synthesis method without requiring additional purification steps
• Exhibits excellent creep resistance at elevated temperature

IP STATUS
A US patent application has been filed.