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Biodiesel is a fuel that can be originated from different raw materials. However, even a good quality biodiesel has its properties strongly dependent upon its fatty acid profile. For instance, samples with a high content of saturated fatty acids may present poor cold flow properties, meaning that they tend to solidify under low temperatures. In this work, we propose to synthesize polymer additives and apply them as cold flow improvers for palm methyl esters (biodiesel) and their blends with petrodiesel. The synthetic additives were evaluated at different concentrations to assess their effect on the pour point (PP) of the resulting neat or blended biofuel. By using 1000 ppm of poly(dodecyl acrylate‐co‐tetradecyl methacrylate), it was possible to decrease the PP of B5 (5 vol.% biodiesel + 95 vol.% diesel) and B20 (20 vol.% biodiesel + 80 vol.% diesel) to −35 °C and −14 °C, respectively, which allowed the use of these blends in regions where their flow properties would eventually be prohibitive. However, the performance of the additive on the neat fuel (B100) was negligible.

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a b s t r a c tThe hydrocolloid extracted from Caesalpinia ferrea var. ferrea seeds purified by membrane filtration was denominated GMPF (14% yield) and contained 75% total carbohydrate and 9% protein, and the mannose to galactose (Man:Gal) ratio was around to 2.1:1.0. The periodate oxidation, methylation and 1D/2D NMR spectra results indicated galactomannan (GM) with a (1 → 4)-linked ␤-d-mannopyranose backbone, partially substituted at O-6 with single-unit ␣-d-galactopyranose side-chains. The splitting of three 13 C signals in the regions of the 4-O-Manp units revealed that the ␣-d-Galp units were irregularly (54%) distributed at the main chain. By rheology, GPC-coupled to multi-detectors, static and dynamic light scattering it was observed that the GM in nitrite solution presented an intrinsic viscosity of 860 mL/g, a polydispersity of 1.55, and a structural parameter (R g /R h ) of 1.77, showing a random coil and flexible conformation, which was confirmed by the Mark-Houwink constant˛(0.63). The results suggest that GMPF can be a new source of GM.

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