Abstract: Octyl-grafted amphiphilic alginate derivative (OAAD) was prepared by hydrophobical modification of sodium alginate (SA) and octyl amine.Then SA/polyvinyl alcohol (PVA) fibers and OAAD/PVA fibers were fabricated by electrostatic-spinning method.Performance of OAAD,the electrospinning solution and the electrospinning fibers were characterized by means of Fourier transform infrared spectroscopy (FTIR),¹H nuclear magnetic resonance (¹HNMR),surface tensiometer,fluorescence spectrum,electrical conductivity,scanning electron microscopy and contact angle measurement.Experimental results showed that octyl amine groups have successfully grafted to the sodium alginate molecular chains.The surface tension of modified alginate is lower than SA and the critical aggregation mass concentration is reduced to 0.60 g·L^-1,which improves the hydrophobicity of SA.Comparing water solubility and hydrophobic properties of SA/PVA electrospinning fibers with that of OAAD/PVA electrospinning fibers,it shows that the dissolution time of modified alginate electrospun fibers completely dissolved in the water rise from 5 h to 48 h,while their contact angle increase from 31° to 57°,which indicates that in comparison with SA/PVA electrospinning fibers,the water-resistant and hydrophobic properties of OAAD/PVA electrospinning fibers have been improved.

Key words: sodium alginate, hydrophobical modification, octyl-grafted amphiphilic alginate derivative, electrostatic spinning, electrospinning fiber