Abstract: In this paper, poly (vinyl alcohol) (PVA) was modified by amino terminated hyperbranched polymer (HBP-NH₂). Based on the function of HBP-NH₂ inducing in-situ regulation of the formation of nano silver, nano silver was assembled in the modified PVA, and the modified PVA/nano silver flexible stress film sensor was prepared. The paper studies the chemical constitution of PVA before and after modification, as well as the mechanical properties and tensile sensing properties of modified PVA/nano silver films. Results indicated that HBP-NH₂ can be grafted onto PVA macromolecular chain effectively with succinic anhydride as an intermediate. The elongation at break of modified PVA film reaches about 341%. Meanwhile, the cross-linking of HBP-NH₂ between molecules makes the modified PVA film have good tensile recovery and fatigue property. During the extensional deformation, the resistance value of the film changed significantly, and increased linearly with the increase of percentage elongation. The film has good cycle stability and can be used for flexible human motion m onitoring.

Key words: polyvinyl alcohol; amino terminated hyperbranched polymer; nano silver; stress sensor; motion monitoring