Design and synthesis of a packaging polymer enhancing the sensitivity of fiber grating pressure sensor

Abstract A packaging polymer (PP-1) that can enhance the sensitivity of fiber Bragg grating (FBG) pressure sensor was designed and synthesized from hydroxyl terminated polypropylene oxide oligomers, toluene diisocyanate (TDI), 1,4-butandiol as chain extender, catalyzer, foam agent and foam stabilizer. The testing results show that the Young’s modulus, Poisson’s ratio of the packaging polymer are 9.0 × 10 6  N m −2 and 0.49, respectively. The static pressure sensitivity of fiber optical Bragg gratings packaged by PP-1 was discussed. The theoretical pressure sensitivity of FBG packaged with the polymer cylinder is −1.73 × 10 −3  MPa −1 , which is 896 times of that of the bare FBG (−1.93 × 10 −6  MPa −1 ). And its measured pressure sensitivity is −1.10 × 10 −3  MPa −1 , which is 558 times of that of the bare FBG.