The poly(L-lactic acid) (PLA) nanofibrous Mat was produced by electrospinning. The PLA nanofibers were thermally bonded at 180 degrees C for different periods of time. The PLA nanofibers were physically welded by thermal treatment without severe structural modification, although their diameters increased due to slight melting of fiber surface. Both tensile strength and elongation at break of the bonded PLA nanofibrous mat were considerably improved, compared to the as-spun mat. Particularly, the increase in elongation at break may be attributed to shrinkage of mat during thermal treatment. (c) 2005 Elsevier B.V. All rights reserved.