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They differ in their properties according to their chemical composition (homo-or copolyester, contained hydroxy fatty acids). They are UV stable, in contrast to other bioplastics from polymers such as polylactic acid, partial ca. temperatures up to 180 °C, and show a low permeation of water.
Good oxygen permeability. Good ultra-violet resistance but poor resistance to acids and bases. Soluble in chloroform and other chlorinated hydrocarbons. [10] Biocompatible and hence is suitable for medical applications. Melting point 175 °C., and glass transition temperature 2 °C. Tensile strength 40 MPa, close to that of polypropylene.
Step-growth polymers increase in molecular weight at a very slow rate at lower conversions and reach moderately high molecular weights only at very high conversion (i.e., >95%). Solid state polymerization to afford polyamides (e.g., nylons) is an example of step-growth polymerization.
Therefore, the molecular structure of a simple monosaccharide can be written as H(CHOH) n (C=O)(CHOH) m H, where n + 1 + m = x; so that its elemental formula is C x H 2x O x. By convention, the carbon atoms are numbered from 1 to x along the backbone, starting from the end that is closest to the C=O group.
This polymer is made up of fructose, a monosaccharide sugar, connected by 2,6 beta glycosidic linkages. Levan can have both branched and linear structures of relatively low molecular weight. [2] Branched levan forms a very small, sphere-like structure [3] with basal chains 9 units long. The 2,1 branching allows methyl ethers to form and create ...
The multiple hydroxyl groups on the glucose from one chain form hydrogen bonds with oxygen atoms on the same or on a neighbour chain, holding the chains firmly together side-by-side and forming microfibrils with high tensile strength. This confers tensile strength in cell walls where cellulose microfibrils are meshed into a polysaccharide matrix.
Glycoproteins have distinct Oligosaccharide structures which have significant effects on many of their properties, [11] affecting critical functions such as antigenicity, solubility, and resistance to proteases. Glycoproteins are relevant as cell-surface receptors, cell-adhesion molecules, immunoglobulins, and tumor antigens. [12]
In polymer science, the polymer chain or simply backbone of a polymer is the main chain of a polymer. Polymers are often classified according to the elements in the main chains. The character of the backbone, i.e. its flexibility, determines the properties of the polymer (such as the glass transition temperature).