Influence of comb type terpolymers of methyl benzyl acrylate-co-hexadecene-maleic anhydride with tetradecyl pendant on cold flow properties of diesel fuel

Abstract

The poor cold flow properties (CFPs) are the main factors that hinder the utilization and popularization of diesel fuel. Cold flow improvers (CFIs) are usually add to diesel fuel to compensate for liquidity problems at low temperatures. In this study, monomers with different functional groups were used to synthesize methyl benzyl acrylate-co-hexadecene-maleic anhydride (MB-HD-MA) terpolymers with different mole ratios through free radical polymerization, and then the terpolymers were modified with tetradecanol to obtain comb type terpolymers (MB-HD-MA-C14). The structure of MB-HD-MA and MB-HD-MA-C14 were characterized by Fourier transform infrared spectroscopy (FTIR) and Nuclear Magnetic Resonance Hydrogen spectra (1 H NMR). Adding CFIs to diesel fuel effectively improved the CFPs, 1000 ppm MB-HD-MA-C14 (3:1:4) presented the best depression effects on cold filter plugging point (CFPP) and solid point (SP) by 12 °C and 21 °C, respectively. The results showed that the non-polar and polar components in CFIs exert synergistic effect at an optimal ratio to improve CFPs with greater efficiency. Moreover, rheology analysis and polarizing optical microscopy showed that MB-HD-MA-C14 (3:1:4) can improve the rheological properties by reducing dynamic viscosity and improve the crystallization behavior of wax crystals at low temperature by decreasing the size and modifying the morphology of the wax crystals.