Universum: технические науки

2.2.3.Cross-linked or network polymers: 
Here the 
monomers are bound together to form a three-dimen-
sional network, the monomers are bound together with 
strong covalent bonds, because it consists of bi-function 
and tri-function in nature between the various polymer 
chains, which can be either linear or non-linear[2, 3]. 
2.3. Based on molecular forces. 
2.3.1.Elastomers
: These materials are materials 
that combine the plasticity and elastic properties. It is 
processed on traditional plastic equipment, for example 
BUNA-S AND BUNA-N
.
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2
]
2.3.2.Thermoplastic polymers:
Plastic polymers 
that change their shape by heat and return to their solid 
state at normal temperature. It is filled with Polyethylene 
and polypropylene, which is used in catheters and oth-
ers[2]. 
2.3.3.Thermosetting :
Also, polymers affected by heat 
change from shape to liquid, and when the temperature 
decreases, it returns to normal. The main physical dif-
ference between it and thermoplastics is that thermo-
plastics can be melted in a liquid, but they are always 
solid and do not return to the liquid state. Examples in-
clude polyurethane, silicone and phenolic [2]. 
2.3.4.Fibers:
This class of polymers appears as 
strings and is easily woven, linked with a hydrogen bond 
or bipolar reaction. It has strong bonds between its mol-
ecules giving it a less elastic trait and high tensile 
strength, for example nylon-66[2]. 
2.4. Based on mode of polymerization. 
2.4.1.Addition polymers:
These polymers that is 
the result of binding monomers such as alkene to one 
another or in addition to cationic root media. Such as 
polystyrene, polyethylene and polyacrylates[2]. 
2.4.2.Condensation 
polymers:
Condensation 
polymerization is a reaction that joins two functional 
groups, such as the alcohol group and the mostly car-
boxyl group, resulting in a portion of water. Such as pol-
yester, polyamide, polysiloxane[2].