Biocomposites from Renewable Resources

Keywords

Calcium alginate • Silane treatment • Blend with polyvinyl alcohol • Blend • Polyvinyl alcohol • Weight loss

Calcium alginate has also been studied as potential reinforcement for polypropyl­ene composites [10Kha]. Calcium alginate fibers with a diameter of 30 ± 10 pm were silane treated and added (10 %) into PP that was pre-pressed into sheets. Layers of alginate fibers were placed between PP sheets, and the sandwich structure was compression molded into composites at 180 °C. Some of the properties of the PP composites containing alginate fibers with and without the silane treatment are given in Table 72.1. As seen from the table, the addition of the alginate fibers had increased the strength, more than doubled the modulus and decreased the elonga­tion by several magnitudes. Bending properties also showed similar increase with the addition of the alginates. Weight loss ranging from 0.5 to 2.2 % was observed when the samples were buried in soil from 2 to 16 weeks. In a similar approach, calcium alginate fibers (120 MPa strength, 4.3 GPa modulus, and 75 % elongation) were mixed with poly(vinyl alcohol) and compression molded into composites [11Dey]. Some of the properties of the alginate reinforced PVA composites are given in Table 72.2. As seen from the table, incorporation of the alginate fibers leads to increase in strength from 10 to 16 MPa and also increase in modulus, but the elongation decreases drastically. Bending properties of the composites doubled. Degradation tests showed that the composites had lost about 50 % of their strength after being buried in soil for 2 months [11Dey].

References

[10Kha] Khan, A., Huq, T., Saha, M., Khan, R. A., Khan, M. A., Gafur, M. A.: J. Compos. Mater. 44(24), 2875 (2010)

Dey, K., Khan, R. A., Chowdhury, A. M.S.: Polym. Plast. Eng. Technol. 50, 698 (2011)

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