SYNTHESIS AND CHARACTERIZATION OF GRAFT COPOLYMERS FROM NATURAL FIBERS
Titel:
SYNTHESIS AND CHARACTERIZATION OF GRAFT COPOLYMERS FROM NATURAL FIBERS
Auteur:
Mtz, Ana M. Mendoza Heinze, Thomas
Verschenen in:
International journal of polymeric materials
Paginering:
Jaargang 51 (2002) nr. 7 pagina's 661-674
Jaar:
2002-07
Inhoud:
The work presented shows that it is possible to graft styrene onto cellulose from Agave lechuguilla and fourcroydes by a simple mechanical disintegration and extraction, the later one studied for the first time. The graft yield can be controlled by the reaction conditions. There is a strong influence of the concentration of aqueous NaOH, which is used as an activation agent, on the graft yield, too. A treatment of the starting material with 12% aqueous NaOH give the best results. For both fibers the mechanically most stable fibers were obtained under the following reaction condition: 0.40 g fiber, 0.25 mol L -1 styrene, 0.025 mol L -1 ceric ammonium nitrate, and 0.25 mol L -1 HNO 3 at a reaction of 4 h at 50°C. Although a higher percentage of grafting may be realized, e.g., by increasing the reaction time to 6 h, the mechanical properties can not be further improved. The highest values of maximum load at all were 1400 g for grafted AL fiber and 1100 g for grafted AF fiber synthesized using reaction conditions. The characterization of the grafted products by means of FTIR, SEM, DRX and 13 C NMR indicates the presence of the styrene grafts. The DSC and TGA investigations show that grafting makes the materials from Agave lechuguilla and fourcroydes thermally more stable. Preliminan, investigations on the biodegradation with microorganism from General Electric Industries show that after 21 days 60% of grafted Al have been degraded compared to 70% in case of unmodifed sample.
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