Polymers biomass

Most analysis methods for the determination of carbohydrates in biomass incorporate a two-stage acid hydrolysis to separate individual polymers and hydrolyze them to simple compounds that can be readily analyzed by chromatographic or spectroscopic techniques. The first stage subjects the biomass sample to a concentrated acid that disrupts the noncova-lent interactions between biomass polymers. A second, more dilute stage follows, which is optimized for complete polymer hydrolysis and minimized degradation of monomeric sugars. Failure to remove nonstructural materials may result in incomplete hydrolysis of... 

As one looks back over the last few decades it is possible to see trends emerging in the ionic liquids that are used and the main foci of interest. Early chloroaluminate systems with potential electrochemical applications gave way to ionic liquids with more air stable anions, with interest moving on to chemicals synthesis and catalysis. Then came new systems with specific properties to use as Task Specific Ionic Liquids (see Chapter 3), or for dissolving biomass polymers (Chapter 10), or as engineering fluids of various types. A small number of papers have now appeared on mixtures of ionic liquids. The exciting thing about ionic liquids is that as each development has occurred it has been in addition to the previous activities and not a replacement for these. 

Yokohara, T., Okamoto, K. and Yamaguchi, M. (2010) Effect of the shape of dispersed particles on the thermal and mechanical properties of biomass polymer blends composed of poly(L-lactide) and poly(butylene succinate). Journal of Applied Polymer Science, 117 (4), 2226-2232. 

As shown in Figure 7.4, there are three general paths for converting biomass polymers (solid phase) to small-molecule fuels (liquid phase) (1) solid gas liquid (S G L), (2) solid liquid (S L), and (3) solid -> gas and liquid liquid (S GL L). The reactions in path 3 are equivalent to the combined reactions from paths 1 and 2. In the following sections, we review specific biomass conversion methods that fall in the categories of path 1 and path 2. 

Concentrated sulfuric acid has been used to dissolve and hydrolyse native cellulose (see Figure 7.6). The concentrated acid can disrupt hydrogen bonding between the cellulose chains and thus decrystallize the eellulose. Then, water is added to rapidly hydrolyse cellulose into glucose. The diluted sulfuric acid is re-concentrated for the next eyele of decrystallization and hydrolysis steps. The final produets inelude a mixture of C5 and C6 sugars. The hydrolysis proeess is generally more complex than pyrolysis or liquefaction. However, hydrolysis enables selective decomposition of the biomass polymers and thus provides access to useful platform chemicals that are unavailable from pyrolysis or liquefaction techniques. 

Designing effective, low-cost, robust, and sustainable catalysts for converting biomass polymers into liquid fuels remains a major challenge and opportunity area for applications of biomass in renewable energy. 

The selection of an appropriate polymer matrix for nanocomposites is especially crucial in terms of the design and development of medical implants and products. Biodegradable polymer matrices can be either of natural or synthetic origin. As shown in Fig. 21.24. Natural, biobased polymers can be dived into three groups directty produced by genetically modified organisms, synthesized from biobased monomers or directly from biomass. Polymers synthesized from biobased monomers are often regarded as synthetic [36,39,40]. 

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