Synthesis of Poly(ether carbonate)-Based Polyurethane for Biodegradable–Recyclable Pressure Sensors

Abstract

Developing biodegradable and recyclable pressure sensors is quite important to broaden their application fields and reduce adverse environmental impact. However, the relevant research in this area is still limited. In this work, a biodegradable and recyclable pressure sensor was proposed by employing biodegradable polyurethanes. The poly(ether carbonate) diol (PEC) with 40% biodegradable groups (carbonate groups) was polymerized with isophorone diisocyanate and butane-1,4-diol to produce a biodegradable PEC-based polyurethane (BPPU) (M n = 5.89 × 10 4 g/mol). Structural analysis of the products was conducted by 1 H NMR and FTIR spectroscopy. The DSC results indicated that the glass-transition temperature of BPPU was −24 °C. In particular, the obtained BPPU showed an excellent biodegradation rate in the soil compared to previously reported polyurethanes, with 72.88% degradation in 103 days. BPPU working as the substrate of a pressure sensor presented high sensitivity (S = 41.29 kPa −1 ), a wide response range (0.62−62.5 kPa), and good durability (6250 cycles). The sensor displayed not only the capability to detect signals of human breathing, joint movements, and writing but also the recyclability of silver interdigital electrodes. At present, the synthesized BPPU shows broad application prospects in flexible sensors with promising low-temperature resistance, biodegradability, and flexibility.

The Horizons of Medical Mineralogy: Structure-Bioactivity Relationship and Biomedical Applications of Halloysite Nanoclay

“…160 A conductive flexible sponge sensor prepared by coating polyurethane (PU) sponge with polypyrrole (PPy)-modified HNTs effectively detected walking, facial expressions, and gestures. 161 PDA-modified HNTs embedded in a PVA matrix combined with Fe 3+ were used to prepare 3D printable materials with a 3-fold increase in electrical conductivity and a 20-fold increase in mechanical stiffness. This material showed potential in the development of human motion-sensing wearable devices (Figure 9g).…”

A Brief Review on Flexible Electronics for IoT: Solutions for Sustainability and New Perspectives for Designers

“…1.49 at 0 to 60% strain; 2.71 at 60-100% strain >1000 [196] Graphite powder and cellulose fibers from waste printing papers 27 1000 [197] Pressure Pressure range and/or sensitivity Polylactic acid piezoelectric film (DS-PLA) 0.03-62 kPa 1.08 million at a pressure of 4.3 kPa [178] Starch, porous carbon 0-250 kPa >1000 [194] Poly(ether carbonate)-based Polyurethane 0.62-62.5 kPa 6250 [198] PPy, paper 4.8 kPa −1 at < 5.5 kPa, 1.7 kPa −1 at 5.5-40 kPa 3D [176] Polyaniline, silk fibroin, poly (lactic-co-glycolic acid), K-carrageenan 165.3 kPa, 2.54 kPa −1 >2000 [183] PDA-CCFN 0 to 50 kPa 1000, by repeatedly loading and unloading a pressure of 20 kPa [185] AgCNT@textile-PDMS 0.02 kPa −1 and 0.004 kPa −1 As can be seen from Table 7, starch has been largely used as a sensing layer for flexible sensing [177,182], and [182] is an extensive review on starch applications; in [178] a sensor based on biodegradable flexible polylactic acid piezoelectric film which achieves significant longitudinal compressive and transverse tensile sensitivities and thus can act either as a pressure sensor or as a tensile sensor is described; a humidity sensor made of a thin film of electrically conductive protein nanowires is presented in [180]. In [176] an interesting solution for implementing an all-organic and all-paper pressure sensor is investigated.…”

Biodegradable Polyurethane Pressure-Sensitive Adhesives Using Biobased Polyols with Distinct Intrinsic Properties

“…Polyurethanes (PUs) are synthesized by the addition of polyisocyanates and polyols. The block structure and different types of polyols lead to versatile properties of PUs and various applications such as coatings, elastomers, and adhesives. , With a suitable formula, PUs are also applied as PSAs. ,, The typical PUs are nonbiodegradable, while recent research on biodegradable PUs has been developed quickly in both academia and industry with the incorporation of biodegradable polyols in the structure of PUs. − Thus, it is promising to apply biodegradable polyols in the synthesis of PUs to produce a type of biodegradable PSA.…”