Polyurethane lignin-derived

Elastomeric, lignin-derived polyurethanes can be produced from a three-component system, in which a polyether diol (like PEG) is used as soft segment, provided that the crosslink density is held at a low level and that the soft segment content is high enough to keep T below room temperature. 

Although most previous research on the use of lignin in structural polymers has dealt with its contribution to polyphenolics and polyurethanes (8), alternatives for crosslinking it with other polymer systems exist as well. These have been summarized recently (9). Among these alternatives are lignin derivatives with acrylate functionality. 

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... 

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. 

Rigid Polyurethane Foams Derived from Kraft Lignin... 

Polyurethane Foams Derived from Lignin- and Molasses Mixtures... 

Nakamura K, Morck R, Reimann A, Kringstad KP, Hatakeyama H (1991) Mechanical properties of solvolysis lignin derived polyurethanes. Polym Adv Technol 2 41-47... 

Nakamura, K., Morck, R., Reimann, A., Kringstad, K., and Hatakeyama, H., 1989, Compression Properties of Polyurethane Foam Derived from Kraft Lignin. In Wood Processing and Utilization (J. F. Kennedy, P. A. Williams and G. O. Phillips, eds.), Ellis Horwood, Chichester, pp. 175-180. 

Earlier work on chain extended HPLs has shown that these derivatives produce uniform (i.e., single phase) polymers with Tg varying in accordance with the Gordon-Taylor relationship (12). Polyurethanes from chain-extended HPLs were found to be rubber-like at room temperature with modulus declining as lignin content is reduced (8). Star-like structure determines functionality, Tg, viscosity, and several other properties that influence utility as polymer segment. 

J Nakano, Y Izuta, T Orita, H Hatakeyama, K Kobashigawa, K Teruya, S Hirose. Thermal and mechanical properties of polyurethanes derived from fractionated kraft lignin. Sen-I Gakkaishi 53 416 22, 1997. 

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). 

A variety of hydroxy-terminated unsaturated polyesters have been evaluated as intermediates in polyurethane foams.These intermediates include the ethoxylated or propoxylated derivatives of lignin-, sorbitol-pentaerythritol-MA condensation products. " MA has also been blended with poly(vinyl chloride) and diisocyanates to obtain cellular PVC materials. "- " ... 

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. 

In order to utilize PU foams for insulation materials, it is necessary to know the thermal conductivity of the sample. Thermal conductivity was measured by sandwiching the PU foam between two plates, whose temperature difference was pre-determined (in this case 27.7°C). Figure 29 shows the relationship between thermal conductivity and LSD content. Time maintained for the equilibration did not affect the results, when time exceeded 20 min. With increasing LSD content, thermal conductivity increased slightly. The above results were compared with commercial grade polyurethane and polystyrene foams. The results are shown in Table 3. The data suggests that the thermal conductivity of PU foams derived from lignin and molasses can be used as alternative materials derived from petroleum. The results indicate that PU foams derived from biopolymers can be used as insulation materials. 

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... 

Wood Panel Derived from Lignin-Based Polyurethane Composites... 

De Oliveira W, Glasser WG (1994) Multiphase materials with lignin 7 Blends of poly(vinyl chloride) with lignin-caprolactone copolymers. J Appl Polym Sd 51 563-571 Toffey A, Glasser WG (1997) Cure characterization of polyurethanes with Ugnin and cellulose derivatives. Holzforschung 51 71-78... 

Hatakeyama T, Izuta Y, Hirose S, Hatakeyama H (2002) Phase transitions of lignin-based polycaprolactones and their polyurethane derivatives. Polymer 43 177-1182 Hatakeyama H, Tanamachi N, Matsumura H, Hirose S, Hatakeyama T (2005) Biobased polyurethane composite foams with inorganic fillers studied by thermogravimetry. Thermochim Acta 431 155-160... 

Hatakeyama H, Nakayachi, Hatakeyama T (2005) Thermal and mechanical properties of polyurethane-based geocomposites derived from lignin and molasses. Comp Part A Appl Sci Manuf 36 698-704... 

This paper concerns the preparation and the thermomechanical properties of environmentally compatible polymers derived from saccharides and lignins at our laboratory. The above research results have been obtained over the last several years. The environmentally compatible polymers include polyurethane (PU) and poly(8-caprolactone) (PCL) derivatives. PU derivatives were prepared from saccharides and lignins. PCL derivatives were synthesized from lignins, saccharides, cellulose and cellulose acetate. The thermal properties of the above polymers were studied by differential scanning calorimetry (DSC), thermogravimetry (TG) and TG-Fourier transform-infrared spectrometry (FTIR). Mechanical properties were measured by mechanical testing. 

Figure 18. Schematic chemical structure of polyurethanes derived from lignin-grafted PCL.

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