Sustainable Triblock Copolymers as Tunable and Degradable Pressure Sensitive Adhesives

Abstract

Pressure sensitive adhesives (PSAs) are widely used in a variety of applications (e.g., sticky note and packing tape). As for most commercial polymer products, current PSA materials are primarily derived from fossil resources and not readily degradable; this has negative environmental consequences. The design of new PSA materials from sustainable resources that possess competitive adhesion properties and degradability is attractive for addressing sustainability concerns. In this work, we prepared a new aliphatic polyester with a long alkyl substituent, poly(pentadecyl caprolactone) (PPDCL), from cashewnut shell liquid derived lactones by ring opening transesterification polymerization in a controlled fashion. The PPDCL was used as the central block in a symmetric triblock copolymer with poly(lactide) end blocks. A series of ABA triblock copolymers were blended with a renewable tackifier to produce sustainable PSA materials. The resultant PSAs showed competitive adhesion properties with many common commercial adhesives. In addition, the ABA triblock copolymers hydrolytically degraded at 50 °C under acidic conditions suggesting they could be attractive as sustainable and degradable PSA materials.

A Morphable Ionic Electrode Based on Thermogel for Non‐Invasive Hairy Plant Electrophysiology

“…EPC_TGS has the second lowest viscosity (≈220 mPa s at 5 °C) and the highest tanδ (≈18 at 5 °C) among all gels/solutions, suggesting high sol fluidity and chain mobility when applied on plants, beneficial for filling surface roughness and thus enhancing conformability and interfacial adhesion. [30,31] We then confirmed the surface activity of EPC polymers through surface tension and contact angle measurements. For instance, only 0.1% w/v EPC added can reduce the surface tension of a saline droplet in air from 71 to 49 mN m −1 (Figure S7, Supporting Information).…”

“…EPC_TGS has the second lowest viscosity (≈220 mPa s at 5 °C) and the highest tanδ (≈18 at 5 °C) among all gels/solutions, suggesting high sol fluidity and chain mobility when applied on plants, beneficial for filling surface roughness and thus enhancing conformability and interfacial adhesion. [ 30,31 ]…”

An Underwater Long‐Term Strong Adhesive Based on Boronic Esters with Enhanced Hydrolytic Stability

“…[ 4 ] Depending on the dissociation mechanism, adhesives comprising supramolecular interactions (hydrogen bonds, [ 5 ] electrostatic interactions, [ 6 ] metal‐ligand coordination [ 7 ] ) exhibit pronounced time‐ or pH‐ dependent behavior, which will gradually lose their original adhesion strengths with sustained loading. [ 8 ] Therefore, strong adhesives based on dynamic covalent networks (e.g., disulfides, [ 9 ] transesterification reactions, [ 10 ] and BO bonds [ 11 ] ) have been developed to adapt to different surfaces with long‐term stability. [ 12 ]…”

“…interactions (hydrogen bonds, [5] electrostatic interactions, [6] metal-ligand coordination [7] ) exhibit pronounced time-or pH-dependent behavior, which will gradually lose their original adhesion strengths with sustained loading. [8] Therefore, strong adhesives based on dynamic covalent networks (e.g., disulfides, [9] transesterification reactions, [10] and BO bonds [11] ) have been developed to adapt to different surfaces with long-term stability. [12] Boron compounds containing BO bonds are very important in chemistry and materials science due to their unique properties.…”

Biosourced All-Acrylic ABA Block Copolymers with Lactic Acid-Based Soft Phase

“…Lactic acid is one of the top value added biomass derived platform chemicals, given its ready availability from sugars through fermentation and its facile conversion into a number of important derivatives [18][19][20]. Among them, polylactide (PLA), most commonly synthesized by the ring-opening polymerization of the cyclic dimer of lactic acid, is a good alternative replacement for the traditional petroleum-sourced polystyrene glassy end-blocks in ABA TPEs, due to their high modulus characteristics [21]. The potential of alkyl lactate esters, e.g., methyl, ethyl and butyl, goes beyond their well-recognized use as eco-friendly solvents [22], as their secondary alcohol offers a simple access to monovinyl derivatives prone to polymerization by radical mechanisms [23][24][25][26].…”