A different type of heat-flow calorimeter is developed to measure the energy of combustion. This calorimeter uses differential thermopile as the heat-flow sensor. The calorimeter and oxygen bomb have a special structure to ensure that the heat generated by combustion heat is slowly transferred to the thermopile, and the temperature of the outside interface of the thermopile is constant. The calorific coefficient is determined by chemical calibration, providing for the chemical calibration S =(64.806 ± 0.029) μV mW −1 , which means uncertainty is 0.05 % for calibration. The combustion enthalpies of anthracene and naphthalene are measured by using this calorimeter, and the results agree with the literature values or recommended values.
A simple and facile method to prepare fully biobased epoxy elastomers with a high toughness is still a big challenge. In this study, a series of fully biobased epoxy elastomers were prepared by curing different epoxidized plant oils with a biobased diamine Priamine 1074. The curing behavior and catalytic process of these biobased epoxy elastomers was systematically studied. The effects of the different numbers of epoxy groups of these epoxidized plant oils and the equivalent ratios of amine and epoxy groups on the performance (thermal stability, mechanical properties, etc.) of the epoxy elastomers were studied and discussed. Furthermore, the potential of these epoxy elastomers as wearable flexible sensors was explored. It is found that ring opening polymerization and ester aminolysis reaction between amine groups of diamines and ester groups of epoxidized plant oils simultaneously occurred during the curing process. The properties, (thermal stability, thermophysical and mechanical properties, etc.) of these epoxidized plant oils could be tailored by selecting epoxidized plant oils with different numbers of epoxy groups and controlling equivalent ratios of amine and epoxy groups. The maximum elongation at break of the epoxy elastomers could reach up to 338.58%. After spray coating with Ag nanowires, these epoxy resins demonstrated excellent detection of motion signals at various joints and other regions of the body. Combining with the results of not being cytotoxic to Caco-2 cells, the epoxy elastomers reported in this study are expected to be applied in the field of wearable flexible sensors.
With the rapid development of flexible electronics and the increasing deterioration of the natural environment, functional and environmentally friendly flexible strain sensors have become one of the frontier research hotspots. Here, we propose a novel strategy to synthesize a functional epoxy elastomer integrating self-healing capability and degradability for flexible stretchable strain sensors. A carboxyl-terminated epoxy prepolymer was first synthesized using carboxyl-terminated PEG (PEG-COOH), 2,2′-dithiodibenzoic acid (DTSA), and 1,4-butanediol diglycidyl ether (BDDE), and then crosslinked by epoxidized soybean oil (ESO) to yield an epoxy elastomer. The obtained elastomer exhibited not only high tensile stress (5.07 MPa), large stretchability (477%), and high healing efficiency (92.5%) but also superior degradability in alkaline aqueous solution. The elastomer-based stretchable strain sensor with microstructure showed high sensitivity (GF = 176.71) and was successfully applied for detecting human motions and recognizing objects with various shapes. Moreover, the healed sensor could restore stable sensing ability. The prepared functional epoxy elastomer is of great significance for the preparation of environmentally friendly and high-performance sensors and is promising for applications in the fields of healthcare monitoring, intelligent robots, and wearable electronics.
危险品化学品经营许可证（带存储）