The smart fabric is a new material that began to develop in the 1990s, and on the basis of the nature and function of original material, it joined the features of intelligent perception. On the performance, intelligent fiber can sense the changes of heat, light, chemistry, mechanical, temperature, and electromagnetic, then react accordingly. For smart textiles, the sensor is the core part, now most commonly used micro/nano strain sensor are using silicon and zinc oxide and others inorganic as main material. But inorganic materials have limited deformation ability, once deformation occurs, the sensor will be strictly damaged. So, the development of flexible, high sensitivity, wide range of strain of the flexible intelligent fiber strain sensor has a very important application prospect. For the stretch-able sensor, the prepared conductive material must be placed on the substrate of the flexible polymer. In this paper, graphene is used as conductive material to construct an orderly conductive layer. Waterborne polyurethane was used as dispersant and adhesive, then strengthen the interface between the layer of conductive material and elastic fabric binding force, and finally prepare a kind of high sensitivity, wide strain range, stable performance and high elastic intelligent fibers.

Epoxy structural adhesive has good mechanical properties, especially high adhesion, low shrinkage rate, and high stability, widely used in steel plate reinforcement, crack repair, bridge splicing, and concrete bonding, etc. However, due to the high cross-linking density and high internal stress after curing, its shortcomings, such as brittleness, the poor performance of fatigue resistance and heat resistance, limit its application in special track engineering. In this work, two kinds of epoxy structural adhesives (EPA-1, EPA-2) with low viscosity and room temperature curing were synthesized by selecting different bisphenol A epoxy resin and active diluent as component A and modified amine curing agent as component B. The results showed that EPA-1 and EPA-2 presented significant toughness compared with the classic construction adhesive (AralditeXH160). The yield strengths of EPA-1 and EPA-2 were 4.88 MPa and 13.13 MPa, and the shear strengths were 11.93 MPa and 13.08 MPa, respectively, showing good adhesive properties. In addition, the viscosities of EPA-1 and EPA-2 were 127 mPa·s and 308 mPa·s, respectively, and their decomposition temperatures were all above ∼280 °C, which indicated that the self-made epoxy structural adhesives could be used for the repair of cracks in the vibration subway tunnel.