Study on performance mechanism of pour point depressants with differential scanning calorimeter and X-ray diffraction methods⋆

Synthesis of methacrylate copolymers and their effects as pour point depressants for lubricant oil

“…9,[19][20][21][22] This prevented the crystals from forming a network and a gel-like structure. Therefore, the pour point of the base oil decreased when the polymethacrylate polymers were added as PPDs.…”

Synthesis and evaluation of alkyl acrylate-vinyl acetate-maleic anhydride terpolymers as cold flow improvers for diesel fuel

“…Many experimental and theoretical studies have been performed to reveal the pour point depressant mechanism and many hypothetical mechanism theories have been formed, in which adsorption, co-crystallization, nucleation, and improved wax solubility are the most widely accepted viewpoints [14][15][16][17][18][19]. Co-crystallization theory is that the nonpolar part of PPD molecules co-crystallizes with wax molecules at wax appearance temperature, while the polar part hinders the wax crystals further growth; Adsorption theory is that wax molecules first crystallize, then PPD molecules adsorb on the surface of the wax crystal particles and change the surface properties by the effect of polar groups; Nucleation theory is opposite to adsorption theory, it considers that PPD molecules first crystallize and become the nuclei of wax growth; Improved wax solubility theory is that PPDs can improve the solubility of wax in the oil, so that they can reduce the amount of wax precipitation.…”

“…Co-crystallization theory is that the nonpolar part of PPD molecules co-crystallizes with wax molecules at wax appearance temperature, while the polar part hinders the wax crystals further growth; Adsorption theory is that wax molecules first crystallize, then PPD molecules adsorb on the surface of the wax crystal particles and change the surface properties by the effect of polar groups; Nucleation theory is opposite to adsorption theory, it considers that PPD molecules first crystallize and become the nuclei of wax growth; Improved wax solubility theory is that PPDs can improve the solubility of wax in the oil, so that they can reduce the amount of wax precipitation. These theories are different and they are still disputed by researchers [16,20]. To completely understand the mechanisms, further studies are necessary.…”

Fatty Acid Alkyl Esters as Feedstocks for the Enzymatic Synthesis of Alkyl Methacrylates and Polystyrene‐co‐alkyl Methacrylates for use as Cold Flow Improvers in Diesel Fuels

“…The high wax crude oils are characterized by high pour point, high viscosity, high gel strength, and abundant wax deposits. Several techniques such as the wintering process [4], blending process [5,6], and additive addition [7] have been used to minimize the problems caused by wax deposition in diesel fuel. Among them, a few polymers having long alkyl side chains, socalled ''comb-like'' polymers, are known to decrease the rate of wax formation.…”