Physical properties of alginate-based materials

The modulus of calcium alginate materials is directly proportional to the level of cross-linking in the systena. Microscopical work has shown that structural differences can be seen on alginate gels by varying the type of the metal ion used in gel formation. The modulus is also dependent on the type of divalent metal used, and increases with increasing affinity of the polyuronate for the divalent metal  

The stiffness of the molecular chain of alginates has been compared with other polysaccharides by Smidsrod et al Alginates are found to be stiffer than the similar polymers like carboxymethylcellulose (Brucker et al and Smidsrod et al ). The stiffness is also dependent upon polymer composition and L-guluronic acid rich alginates posses a more rigid chain conformation than D-mannuronic acid rich alginates. The molecular stiffness of the three types of alginate blocks in solution decreases in the order  

Alkali resistant alginates (beryllium and chromium) have few ionic bonds but considerable coordinate links, which are more stable. These links decrease extensibility but increase tenacity of the fibers. 

Chamberlain et al. found that there is a relationship between metal content and tensile strength and that a 10% metal content gave the highest fiber strength. Moussavi reviewed the physical properties of alginate produced by other workers and the results are summarized in Table 3.3. 

Type of alginate Tenacity (cN tex h Extension at break (%) Density (g cm ) Reference 

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