Polyols lignin-derived

Various types of lignin-derived polyurethane products and their precursors appeared to satisfy these constraints. This paper summarizes experimental efforts aimed at developing lignin-derived polyol, polyisocyanate, and polyurethane products. 

Lignin-PeAtund PoZyuA.ztka.nte. The manufacture of polyurethane foams, adhesives and coatings from lignin-derived polyes-ter-ether-polyols and various commercial diisocyanates has been accomplished and reported earlier (16,17,18). Foam properties... 

Figure 7. Infrared spectra of isocyanate formation of model Type C (R = CHS) (Spectrum A, azide and Spectrum B, isocyanate) and of capped lignin-derived polyol.

Economic Analysis (1975) of the Production of Lignin-Derived Polyols (After Clark (20))... 

Attempts to increase the lignin content in polyurethane products via either increased lignin contents of the polyols, or via the formulation of lignin-derived polyisocyanates, have so far largely failed. This is primarily attributed to lignin s limited solubility characteristics. 

LS is obtained as a by-product of sulfite pulping process. LS has not been used as a chemical component of common lignin-based polymers such as epoxy resins due to its ionic nature. LS is soluble in water and, at the same time, it is soluble in some kinds of solvent such as ethylene glycol, DEG, TEG, and PEG. [157]. LS-based PU foams can be prepared from LS-based polyols, LSD derived from DEG, LST from TEG, and LSP from PEG. The thermal and mechanical properties of rigid PU foams... 

Li.gru.n-VeAd.ved Potyi ocqanaXeA Efforts to increase the incorporation of lignin into polyurethane products have concentrated on transforming polymeric lignins into polyisocyanates useful for reacting with polyols. Two alternative reaction pathways have been explored with the three lignin-like model compounds shown in Figure 3. These models were vanillic acid or a derivative thereof (Model Type A) a derivative of tetralin di-carboxylic anhydride (Model Type B) and a derivative of a styrene-maleic anhydride copolymer (Model Type C). 

Propylene oxide is one of the top 50 chemicals. More than 4 million t/a are produced worldwide. It is reacted via polyetherpolyols to form polyurethanes and via propylene glycol to form polyesters 15). Obviously, the polyol and diol functionalities are used to form with diisocyanates derived from diamino compounds polyurethanes and with diacids polyesters, respectively. These functionalities are available from renewable feedstocks carbohydrates, oils and fats, proteins and lignins. 

All currently important industrial organic chemicals such as hydrocarbons, alcohols, polyols, ketones, acids, and phenol derivatives can be obtained by chemical processing of wood [106]. Plastics and synthetic fibres produced could be synthesized using the above chemicals from plant components. In order to develop both current and new polymers, eombining petrochemistry with wood chemistry has been considered. In this section, novel polymers synthesized using lignin degradation products are described [107, 108]. 

In this section, PU composites are designed using plant components in both matrix and filler, i.e. two types of lignin-polyol derived from KL and LS are used to prepare polyurethane matrix and wood powder as fillers [165, 166]. In order... 

Lignin polyols were prepared using KL or LS which was solved in DEG, TEG, or PEG. In order to control the reaction, polyols obtained from ML were also added. Figure 42 shows examples of PU composites derived from LSP/MLP, 50/50 mixture, filled with A1 (011)3. The mixing ratio of A1 (011)3 is shown as wt% in total polyol. The dark brown colour comes from colour of LS. 

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