Reversibly Cross-linkable Bottlebrush Polymers as Pressure-Sensitive Adhesives

Abstract

Dynamically cross-linkable bottlebrush polymer adhesives were synthesized by the grafting-from strategy through a combination of ring-opening metathesis polymerization (ROMP) and photoiniferter polymerization. A norbornene-containing trithiocarbonate was first polymerized by ROMP to form the bottlebrush polymer backbone; this was followed by blue-light-mediated photoiniferter polymerization of butyl acrylate initiated by the poly(trithiocarbonate) to form the bottlebrush polymer. This strategy afforded well-defined bottlebrush polymers with molar masses in excess of 11 000 kg/mol. For un-cross-linked bottlebrush polymers, 180° peel tests revealed a cohesive failure mode and showed similar peel strengths (∼30 g/mm) regardless of the backbone polymer degree of polymerization (DP). The bottlebrush polymers were then treated with butylamine to remove the trithiocarbonate, liberating thiols on each side-chain terminus. In the presence of oxygen, these thiols readily cross-linked via disulfide bond formation. The cross-linked bottlebrush polymers with a backbone DP of 400 showed a greater than sixfold improvement in peel strength, whereas those with a backbone DP of 100 exhibited a twofold enhancement compared with un-cross-linked samples along with a change to adhesive failure. Triphenylphosphine readily reduced the disulfide bonds, effectively removing all cross-links in the bottlebrush network and allowing for recasting of the adhesive, which showed similar adhesive and rheological properties to the original un-cross-linked samples.

Life Cycle Assessment and Techno-Economic Analysis of Pressure Sensitive Bio-Adhesive Production

“…It is recommended to include operating parameters in the future analysis to explore how operating condition changes may impact the economics. In addition, since PSA can also be prepared from other polymerization process such as photoiniferter polymerization, which has the ability to maintain the radical at a low concentration and ambient temperature [51], future TEA and LCA research could also focused on exploring the most sustainable polymerization process in PSA production. glycerol price, acrylic acid price, 3-chloro-2-butanone price, and catalyst price were among the top most sensitive factors.…”

Grubbs’ and Schrock’s Catalysts, Ring Opening Metathesis Polymerization and Molecular Brushes—Synthesis, Characterization, Properties and Applications

“…Exceptionally large bottlebrush nanoparticles were considered for production of hybrid materials for many important applications by Watkins and his team [70,71]. Matson and his team investigated the adhesive properties of P n BA bottlebrushes, which were reversibly cross-linked [168].…”

Robust and recoverable dual cross‐linking networks in pressure‐sensitive adhesives

“…Pressure-sensitive adhesives (PSAs) are viscoelastic materials that are designed to adhere to various substrates by a light external force and easily removed after use. [1][2][3] They have been used in a wide range of applications, such as adhesive tapes, labels, sticky notes, display products, and medical products because of their ease of use and relatively low-cost strategy for controlling the bonding process. [4][5][6] It is well documented that PSAs require the balance of both adhesion (characterized by tack and peel) and cohesion (characterized by shear resistance) for the enhancement of their performance.…”

“…Pressure‐sensitive adhesives (PSAs) are viscoelastic materials that are designed to adhere to various substrates by a light external force and easily removed after use 1–3 . They have been used in a wide range of applications, such as adhesive tapes, labels, sticky notes, display products, and medical products because of their ease of use and relatively low‐cost strategy for controlling the bonding process 4–6 .…”