Methylcyclohexyl methacrylate–methacrylate copolymers: an effective cold flow improver for the biodiesel blends.

The poor cold flow property is one of the main obstacle factors in affecting the utilization of high proportion biodiesel blends in engines. In this study, methylcyclohexyl methacrylate–methacrylate copolymers (MCHMA-R₁MC, R₁ = C₁₂, C₁₄, C₁₆, C₁₈) were synthesized at various molar ratios by radical polymerization, and their structures were analyzed and characterized by FTIR, GPC, and ¹H NMR. These resulting copolymers were used as the cold flow improvers for biodiesel/diesel blends in terms of cold filter plugging point (CFPP) and solid point (SP) measurement. Results showed that the CFPP and SP of B20 decreased to a varied extent after MCHMA-R₁MC treatment. When the monomer ratio of was 1:7, MCHMA-C₁₄MC (1:7) exhibited the greatest reduction on the CFPP and SP of B20 by 18 °C and 25 °C at 2000 ppm dosage. The effects of MCHMA-R₁MC copolymers on crystallization behavior and morphology were studied through polarizing optical microscope, differential scanning calorimetry and viscosity–temperature curves. The results indicated that MCHMA-C₁₄MC could effectively delay the aggregation of wax crystals and change their crystalline behavior by changing the crystal shapes and inhibiting the formation of large wax crystals and then lower the low-temperature viscosity of biodiesel blends; therefore, MCHMA-C₁₄MC has proven to be a high-effective cold flow improver for the biodiesel blends. [ABSTRACT FROM AUTHOR]