PHYTOMASS CELL WALL MACROMOLECULES CHARACTERIZATION AFTER STEAM EXPLOSION AND

APPLICATIONS IN WOOD COMPOSITESRamunas Tupciauskas1, Janis Abolins2, Andris Veveris1, Brigita Neiberte1, Anrijs Verovkins1,

Marlei Scariot3, Enrique Ortega3, and Janis Gravitis1

1Lab. Biomass Eco-Efficient Conversion, the Latvian State Institute of Wood Chemistry, Dzerbenes Street 27, Riga, LV-1006 Riga, Latvia

2Institute of Atomic Physics and Spectroscopy of the University of LatviaRiga, LV-1586, Latvia, e-mail: jclover@latnet.lv

3Ecological Engineering Lab, Food Eng. Scool. State University of Campinas FEA, Unicamp Caixa Postal 6121 CEP 13083-862, Campinas, SP, Brazil

The steam explosion auto-hydrolysis (SEA) is a rather simple technology allowing to achieve decomposition and defragmentation of wood and other natural composites to nano-size particles that can be used as a source of man-made composites, chemicals, and fuels for combustion engines and fuel cells. Considerations referring to the SEA technology and applications of lignin extracted from steam-exploded wood biomass in hot-pressed composite boards and plywood are presented.

Fig, 1. Utilization of railway sleepers by clean charcoal process

The study has been made to design clusters of integrated bio-refineries for utilization of waste wood (Figs. 1, 2) and cell wall macromolecules. The design and modelling includes multiple analyses of macromolecules and quantitative indicators of sustainability.

Fig. 2. From technological wood chips to steam explosion auto-hydrolysis to self-binding materials to plywood binders.

Materials for hot-pressed board samples were studied by L&W Fibre Tester analyser, Mettler Toledo DSC822 differential scanning calorimeter and TGA/SDTA851 thermal gravimeter, and Perkin Elmer “Spectrum One” Furrier-transform infrared spectrometer. All lignins have been characterized by analytical methods using group content value.

Sample F1 F2 F3

Number of fibres 14502 20042 20014

Temperature at testing, ºC 40,5 40 39,3

Average length, µm 855 799 637

Average width, µm 30,9 26,4 29,6

Shape, % 84,8 85,9 86,3

Fines, % 10,2 11,6 29,9

Coarseness, µg/m 339 172 225

Aspect ratio 27,7 30,3 21,5

Table 1. Determined fibre parameters

Characterisation of grey alder woodThe methoxyl content is determined by classical Zeisel-Vieböck-Schwappach method based on quantitative reactions [Zakis G.F. Functional Analysis of Lignins and Their Derivatives. TAPPI Press: Atlanta, GA, 1994, 94 p.]:Lig-OCH3 + HI → Lig-OH + CH3ICH3I+ Br2 → CH3Br + IBrIBr + 2Br2 +3H2O → HIO3 + 5HBrHIO3 + 5HI → 3I2 + 3H2O3I2 + 6Na2S2O3 → 6NaI + 3Na2S4O6

Content of –OCH3 groups in lignin samples is calculated from an equivalent amount of iodine determined by titration with Na2S2O3.Phenol and carboxyl OH groups in lignin extracted from SE mass is determined by conductometric titration on a „Radiometer Analytical” CDM210 Conductivity Meter the measuring equipment accessories being provided by MeterLab.

Shape – the ratio of the perceptible to the actual fibre length. Fines – fibres less than 0,2 mm. Aspect

ratio – AS = average length/average width.

References Abolins J., Gravitis J., (2007), Biomass conversion to transportation fuels, combustibles, and nano-materials by steam explosion, Latvian J. Phys. and Techn. Sci., 4, 29-39. Abolins J., Tupciauskas R., Veveris A., Alksnis B., Gravitis J., (2008), Effects of Steam Exploded Lignin on Environmentally Benign Hot-Pressed Alder Boards. The 7th International Conference on Environmental Engineering. Selected Papers. D. Cygas D., K. D. Froehner K. D. (Eds.), Vilnius Gediminas Technical University Press „Technika”, Vol. 1, 1-7.

Conclusions Steam explosion auto-hydrolysis opens the way to self-binding board

composites. The functional group analysis correlates with conditions of sample

treatment

SampleOCH3 average,

%

Standart deviationSdev

Average ± 2 Sdev

Grey alder, raw chips 6.34 0.08 6.34 ± 0.16

SE mass, 1 min, dried 5.69 0.01 5.69 ± 0.02

SE mass, 1 min, water rinsed 6.27 0.13 6.27 ± 0.26

SE mass, 1 min, residue 3.08 0.14 3.08 ± 0.28

SE lignin, 1 min 16.19 0.07 16.19 ± 0.14

SE lignin, 2 min 15.43 0.04 15.43 ± 0.08

SE lignin, 3 min 14.80 0.03 14.80 ± 0.06

Table 2. Methoxyl analysis of grey alder (two independent procedures)

GroupAverage,

%Sdev ,

%Average ± 2 Sdev

SE 235 °C, 1 minute

OHphen 4.31 0.21 4.31 ± 0.42

OHCOOH 2.70 0.40 2.70 ± 0.80

OHtotal 7.01 0.53 7.01 ± 1.06

SE 235 °C, 2 minutes

OHphen 5.33 0.30 5.33 ± 0.60

OHCOOH 3.03 0.10 3.03 ± 0.20

OHtotal 8.37 0.40 8.37 ± 0.80

SE 235 °C, 3 minutes

OHphen 5.47 0.09 5.47 ± 0.18

OHCOOH 3.30 0.10 3.30 ± 0.20

OHtotal 8.77 0.14 8.77 ± 0.28

Table 3. Content of hydroxyl groups in lignin extracted from SE grey alder wood (three independent procedures)