# Utilization of Polymeric Materials toward Sustainable Biodiesel Industry: A Recent Review
## 4 Cold-Flow Improvers
### Polymeric CFIs for Blended Biodiesel/Diesel  
Despite the enhancement achieved by blending biodiesel with diesel fuel, using polymeric CFIs recorded better improvement. [PERSON] et al. [30] applied copolymers of C9-C22 \(\alpha\)-olefins on a blend of waste cooking oil biodiesel and diesel. 0.04 wt% of referred polymeric CFIs reduced 8 \({}^{\circ}\)C in CP and 7 \({}^{\circ}\)C in PP. Similarly, B20 of waste cooking oil biodiesel was subjected to 0.08 wt% of EVA copolymer. The results recorded reduction 8, 10, and 11 \({}^{\circ}\)C in CP, PP, and CFPP, respectively [103]. EVA copolymer was also applied on B50 of rapeseed biodiesel with 320 ppm as a concentration. However, the enhancement was remarkable in CFPP, at 17 \({}^{\circ}\)C [108]. B20 blending of coconut biodiesel gained improvement in cold-flow properties, specifically 3, 8, and 9 \({}^{\circ}\)C in CP, CFPP, and PP, respectively when 0.03 wt% of poly(methyl acrylate) was added to the blended fuel [109]. Lastly, poly(acrylic acid) and poly(tetradacyl methacrylate) were added to a B20 blend of palm oil biodiesel with a concentration of 0.1 wt%. The result recorded a 7 \({}^{\circ}\)C reduction in PP [29]. Table 8 summarizes the literature regarding the application of polymeric CFIs for blended biodiesel/diesel fuel.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Polymeric CFIs**} & \multirow{2}{*}{**Biodiesel**} & \multirow{2}{*}{**Concentration (wt%)**} & \multicolumn{2}{c}{**The Effect**} & \multirow{2}{*}{**Reference**} \\ \cline{3-3} \cline{5-6}  & & & **Property** & & **Reduced Value (\({}^{\circ}\)C)** \\ \hline \multirow{4}{*}{Ethylene/vinyl acetate copolymers} & \multirow{4}{*}{EVA} & Waste cooking oil & \multirow{2}{*}{0.02–0.08} & CFPP & 2 \\ \cline{3-3} \cline{5-6}  & & Soybean & 0.01 & PP & 2 \\ \cline{3-3} \cline{5-6}  & & Waste cooking oil & 0.02–0.08 & PP & 3 \\ \cline{3-3} \cline{5-6}  & & Canola & 1 & PP & 11 \\ \cline{3-3} \cline{5-6}  & Keroflux (BASF), ethylene/vinyl acetate/acrylate & Blended rapeseed and soybean oil & \multirow{2}{*}{0.3} & CP & 2 \\ \cline{3-3} \cline{5-6}  & Poly(dodecyl methacrylate) & & & CFPP & 9 \\ \hline \multirow{4}{*}{Polyacrylates and related copolymers} & Poly(heckadecyl methacrylate) & Canola & 1 & PP & \(-\)46 \({}^{*}\) \\ \cline{3-3} \cline{5-6}  & Poly(heckadecyl methacrylate) & Canola & 1 & PP & \(-\)20 \({}^{*}\) \\ \cline{3-3} \cline{5-6}  & polymethyl acrylate & Waste cooking oil & 0.02–0.08 & PP & 8 \\ \hline \multirow{4}{*}{Maleic anhydride copolymers} & Poly(MA-alt-1-octadecene) & Palm oil & 2 & PP & 6 \\ \cline{3-3} \cline{5-6}  & poly(MA-alt-1-octadecene) & Tobacco seed oil & 1 & CFPP & 7 \\ \cline{3-3} \cline{5-6}  & octadecyl vinyl ether & Canola & 1 & PP & 3 \\ \hline \hline \end{tabular} \({}^{*}\) These are the total values of PP.  
\end{table}
Table 7: _Cont._  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Polymeric CFIs**} & \multirow{2}{*}{**Biodiesel/Diesel Blend**} & \multirow{2}{*}{**Concentration (wt%)**} & \multicolumn{2}{c}{**Effect**} & \multirow{2}{*}{**Reference**} \\ \cline{3-3} \cline{5-6}  & & & **Property** & & **Reduced Value (\({}^{\circ}\)C)** \\ \hline Polyolefin (copolymers of C9–C22 \(\alpha\)-olefins) & Waste cooking oil/diesel & \multirow{2}{*}{0.04} & CP & 8 \\ \cline{3-3} \cline{5-6}  & & & PP & 7 \\ \hline \hline \end{tabular}
\end{table}
Table 8: Some polymeric CFIs for blended biodiesel/diesel.