“…Figure 3a shows a comparative FTIR spectrum study of BNNTs, nPCL and nPCL/BNNTs. BNNTs have characteristics bands which are a strong asymmetric band centered at 1380 cm −1 , which corresponds to the bond B-N stretch, along with a less intense band at 790 cm −1 attributed to B-N-B bond [26]. The main absorption bands in the infrared for nPCL are 2949 cm -1 and 2865 cm -1 associated with asymmetrical and symmetrical stretching of CH 2 , respectively, 1727 cm -1 associated with the stretching of the carbonyl, 1293 cm -1 to CO and CC stretching in the crystalline phase, 1240 cm -1 associated with the COC asymmetric stretching and 1170 cm -1 associated with the COC symmetrical stretching [27,28].The presence of the band at 790 cm -1 in the nPCL/BNNTs indicates again the presence of BNNT in the nPCL.…”