Strengthened, Recyclable, Weldable, and Conducting-Controllable Biobased Rubber Film with a Continuous Water-Soluble Framework Network

Abstract

At present, recycling of rubbers is the main method to achieve their sustainable development. However, it is a challenge to recycle rubbers without retaining pristine reinforcing-fillers. Herein, we report fully biobased rubber films prepared by mixing epoxidized natural rubber (ENR) latex and carboxymethyl chitosan (CMCS) solution. CMCS was regenerated and selectively located in the interstitial space between the ENR latex particles during the film-forming process, forming a CMCS framework network in the films. The special CMCS network with hydrogen bonding interactions with ENR endowed rubber films with improved mechanical properties. At the same time, the self-sticky characteristic of ENR with the assistance of chain diffusion and reversible hydrogen bonding interactions made the cut films to be welded. Because the water-soluble CMCS is a continuous phase, the ENR could be perfectly recycled by soaking films in water to remove the CMCS. Furthermore, the CMCS framework running through the whole films provided a wonderful 3D network for conducting. The ENR/CMCS films could turn into conductive films when the moisture content was higher than 1 wt %. The conductivity of the ENR/CMCS films could be tailored conveniently by controlling the moisture content or changing the concentration of the electrolyte in the absorbed water. Thus, we provide a convenient approach to prepare strengthened, recyclable, weldable, and conductive biobased rubber films that can find applications in humidity sensors.

Strengthened, Self-Healing, and Conductive ENR-Based Composites Based on Multiple Hydrogen Bonding Interactions

“…Finally, the swollen samples were dried to constant weight in the fume hood. The swelling ratio of the composites in toluene can be obtained using eq : …”

Polymer‐assisted fully recyclable flexible sensors

“…Regardless of recycling conditions, a growing number of recyclable polymers including thermoplastic polymers and crosslinked polymers with reversible bonds can be plausibly extended as assistant materials in electronic manufacture. [13][14][15][16][17] However, most sensing materials typically composed of solid semiconductors are poorly recyclable because they can be hardly reconfigured. It has been proposed that fully recyclable electronic sensors might be fabricated by means of blending sensing materials within recyclable polymers.…”

“…Both the sensing material and assistant matrix have to accord with the feature of easy recyclability. Regardless of recycling conditions, a growing number of recyclable polymers including thermoplastic polymers and crosslinked polymers with reversible bonds can be plausibly extended as assistant materials in electronic manufacture 13‐17 . However, most sensing materials typically composed of solid semiconductors are poorly recyclable because they can be hardly reconfigured.…”

Structure and Performance of Carboxylic Styrene Butadiene Rubber/Citric Acid Composite Films

“…Recently, many efforts have been focused on using natural polymers not only to reinforce rubbers but also to endow them with new functional applications, such as self-healing, − shape memory, conducting, − and so on. Xu et al fabricated strengthened rubber films by adding carboxymethyl chitosan (CMCS) into carboxylic styrene butadiene rubber (XSBR).…”

“…Ramírez-Hernández et al prepared banana starch/NR films, which could be biologically degraded after 60 days. Nie et al fabricated a continuous framework network of CMCs, which endowed epoxidized NR (ENR) with better mechanical properties and conductive ability when the moisture content was higher than 1%. Loykulnant et al prepared antibacterial NR composites with chitosan.…”