PET threads were incorporated in the support layer of hollow fiber membrane in axial direction as a special reinforcement material for the purpose of improving the mechanical properties of PVDF hollow fiber membranes. it was found that the reinforcement threads had a limited effect on the separation-related properties of the membrane, such as porosity and pore size, but the tensile strength of the reinforced membrane was improved several folds. Also, the criterion of choosing reinforced fiber materials was suggested. (C) 2009 Elsevier B.V. All rights reserved.