By Yebo Li, Xiaolan Luo, Shengjun Hu
This short outlines the latest advances within the construction of polyols and polyurethanes from renewable assets, quite often vegetable oils, lignocellulosic biomass, starch, and protein. the common methods for the creation of polyols from all the above pointed out feedstocks are brought and the homes of the consequent polyols and polyurethanes also are discussed.
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Extra resources for Bio-based Polyols and Polyurethanes
Cai C, Dai H, Chen R, Su C, Xu X, Zhang S, Yang L (2008) Studies on the kinetics of in situ epoxidation of vegetable oils. Eur J Lipid Sci Tech 110:341–346 18. Vlček T, Petrović ZS (2006) Optimization of the chemoenzymatic epoxidation of soybean oil. J Am Oil Chem Soc 83:247–252 19. Miao S, Zhang S, Su Z, Wang P (2010) A novel vegetable oil-lactate hybrid monomer for synthesis of high-Tg polyurethanes. J Polym Sci Pol Chem 48:243–250 20. Rüsch gen Klaas M, Warwel S (1999) Complete and partial epoxidation of plant oils by lipase-catalyzed perhydrolysis.
Ozonolysis-derived polyols typically have low molecular weights due to loss of part of the fatty acid chains that result from double bond cleavages . 2 Vegetable Oil-Based Polyols and Polyurethanes 27 reported to have varied properties, such as hydroxyl numbers from 152 to 260 mg KOH/g and acid numbers from 2 to 52 mg KOH/g [58–60]. The high acid numbers are attributed to carboxylic acids, which form during ozonation processes and cannot be reduced to alcohols under subsequent hydrogenation conditions [58–60].
Castor oil can be converted to polyols with higher molecular weights and lower hydroxyl numbers by ethoxylation (alkoxylation with ethylene oxide) or propoxylation (alkoxylation with propylene oxide) . Due to the incorporation of long polyether chains from castor oil, high quality flexible PUs such as foam mattresses can be produced. 7 shows a schematic synthetic route for castor oil-based polyols via ethoxylation. In addition to these two modiﬁcation methods, mixing castor oil with petrochemical-derived polyols is also an effective way to obtain fast reaction rates with isocyanates and to ﬁne-tune product properties in the PU production process.