Tetradecyl methacrylate-N-methylolacrylamide Copolymer: A low concentration and high-efficiency pour point depressant for diesel

To obtain the pour point depressants (PPDs) of low concentration and high efficiency for diesel, three copolymers of tetradecyl methacrylate-co-cinnaamide (C14MC-CA), tetradecyl methacrylate-co-N-phenylacrylamide (C14MC-NPA) and tetradecyl methacrylate-co-N-methylolacrylamide (C14MC-NMA) with different molar ratios were prepared and characterized by Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1 H NMR), gel permeation chromatography (GPC). The effect of these copolymers on the low-temperature fluidity of diesel were investigated by the measurement of cold filter plugging point (CFPP) and solid point (SP). Results showed that all the three PPDs have obvious improvements on the low-temperature fluidity of diesel. Among that, C14MC-NMA presented a better impact in reducing the CFPP while C14MC-NPA and C14MC-CA exerted better depressive effect on the SP. Based on the double consideration of performance and economy, 750 ppm C14MC-NMA (9:1) possessed the optimal depressive effect for diesel, and the CFPP and SP were reduced by 11 °C and 24 °C, respectively. The depressive effects of C14MC-NMA (9:1) were compared with other PPDs in latest reports and it can achieve the same effects as other PPDs with less than half of the previous dosage. In addition, through differential scanning calorimetry, polarizing optical microscopy and viscosity–temperature curves, the mechanisms of the interaction between these PPDs and diesel were studied.