NBR samples with known contents of acrilonitrile (AN) were prepared at IAE laboratories as reference samples for producing an analytical curve to determine the content of AN and NBR, using new methods of transmission (pyrolysis) and UATR/FT-IR techniques. The chosen FT-IR analytical band for AN was 2237 cm-1 for transmission (pyrolysis) and UATR technique. The reference band chosen in transmission pyrolysis technique was 1455 cm-1. Values of A2237/A1455 relative absorbance (transmission pyrolysis technique) and of A2237 (UATR technique) vs. the AN contents data were used to elaborate analytical curves with good linear correlations (R = 0.995 e R = 0.989) - transmission pyrolysis technique) and R = 0.996 (UATR technique), which allows one to determine contents of AN in NBR samples of similar composition. Even though the techniques showed similar accuracy, the time required for the analysis is smaller with the UATR technique, especially if the time for extraction for applying the transmission pyrolysis technique is also considered.
Acrilonitrile; butadiene-acrilonitrile copolymer; FT-IR; transmission pyrolysis; UATR
