A new kind of nanohybrid poly(tetradecyl methyl-acrylate)-graphene oxide as pour point depressant to evaluate the cold flow properties and exhaust gas emissions of diesel fuels

•The PMA14-GO nanohybrid PPDs exhibited better cold flow properties.•Diesel fuel treated with 0.2wt% PMA14-6GO exhibited the best depression on CFPP, while 0.2wt% PMA14-9GO showed the best depression effect on SP.•PMA14-GO nanohybrid PPDs could effective improve the low-temperature viscosity of diesel fuels.•PMA14-GO nanohybrid PPDs effectively modified the crystal morphology and crystallization behavior of diesel fuels.•The exhaust gas emissions of PMA14-GO nanohybrid PPDs on diesel fuels were reported. In this paper, a new kind of nanohybrid poly(tetradecyl methyl-acrylate)-graphene oxide (PMA14-GO) as pour point depressant (PPD) was prepared from graphene oxide, using matrix via in situ free radical polymerization. The effect of PMA14-GO (i.e., PMA14-3GO, PMA14-6GO and PMA14-9GO) PPDs on the cold flow properties and exhaust gas emissions of diesel fuels were studied. Results indicated that PMA14-GO PPDs exhibited a better effect on cold filter plugging point (CFPP) and solidifying point (SP) than that of PMA14. Among them, PMA14-6GO and PMA14-9GO were the most suitable candidates for improving CFPP and SP. Specifically, upon addition of 0.2wt% PMA14-6GO could reduce the CFPP of diesel by 14°C, and 0.2wt% PMA14-9GO reduced the SP of diesel by 19°C. Moreover, PMA14-GO PPDs could effectively lower the low-temperature. Other fuel properties were also determined and compared with the ASTM D975. Given the heterogeneous nucleation mechanism, uniform and tiny particle-shaped crystals were observed by polarizing optical microscopy and differential scanning calorimetry. In addition, burning diesel fuel with PMA14-GO PPDs effectively reduced HC and CO emissions, whereas NO and CO2 emissions increased with the increased engine speed at full load.