The cold crystallization behavior of poly (L-lactide) (PLLA) blend films modified by small amount of acrylic rubber particles (ACR) have been investigated by in situ Fourier-transform infrared (FTIR) spectroscopy. During the isothermal cold crystallization, the crystallization rate of PLLA is greatly improved with addition of only 1 wt % ACR. However, for PLLA with 8 wt % ACR, the crystallization rate is slower than that of neat PLLA. The relative crystallinity of PLLA with the addition of 15 wt % ACR is obviously higher than that of the neat PLLA. For the PLLA blend film with 3 % ACR, the relative crystallinity reaches a maximum. It was found that the addition of ACR particles below 5% accelerated the cold crystallization nucleation process and made the cold-crystallization rate of PLLA/ACR be quicker than that of neat PLLA. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013