| Glue 2 | |
|
On
the inside of this quaternary structure are many glycine and alanine
amino acids (among other amino acids) and on the outside are several
hydroxyproline acids, of which their locations and structure give collagen
its properties and shape. One
such property that lends itself to the properties of glue is that collagen
is elastic, due to the coils and cross-link hydrogen bonds that make
up its structure. When
collagen is boiled in water, the coils separate in the solution, as
the hydrogen bonds are denatured and the bonds are broken, where water
has attracted the protein to pull apart. As the solution cools and water evaporates, the collagen's
hydrogen bonds try to reform where they were once broken, however they
are unable to align in their original positions. This new
formation of collagen is the extracted glue, also known as impure extracted
gelatin, of which its hydrogen bonds can interact with the adherends,
and its new formation also has polar and ionizable sections to help
with further attractions with the adherends.
|
Note: Adding a filler to hide glue, such as calcium carbonate (CaCO3) will make the glue more resistant to water, however it also decreases the glues tensile strength (the amount of force needed to pull the adhesive completely apart). Calcium carbonate is a good moisture barrier, as it fills the space between the glue’s molecules, however, since it does not add to the attractions in the adhesive process, it makes the glue less effective as a strong adhesive. Calcium carbonate also makes the glue less flexible as it fills the spaces.
|
