Page 60 - Template Tesis UTM v2.0

proceeding sub-section will only describe two types of thermoset in details, which are

epoxy and polyester resin.

2.8.1.1 Epoxy

Epoxy resins are broadly used in the application of composite structures and
they offer some unique properties which unattainable with other thermoset matrices

such as high strength, excellent interfacial bonding to numerous substrates, chemical

resistance, low shrinkage and low toxicity. Hence, it is widely used in aerospace
application in the fabrication of vertical and horizonal stabilisers, wing and fuselage.

There are three main elements when dealing with thermoset system namely as base
resin, curatives and modifiers which unconditionally affecting the mechanical and

physical of the composite components. Amines, amine derivatives and anhydrides are
the most of chemical groups of curatives while rubbers, thermoplastics, diluents, flame

retardants, fillers, dyes and pigments are the main categories of modifiers used in

epoxy resin. The main advantages of epoxies are as follows;

• Inherent polar nature that confers excellent adhesion to a wide variety of fibres

• Relatively low cure shrinkage that makes dimensional accuracy of fabricated
structures easier to obtain

• No volatile by-products of the curing reaction to cause undesired bubble or

void formation
• Cross linked structure that confers excellent resistance to hostile environments,

both aqueous and non-aqueous.

2.8.1.2 Polyester

Polyester resins are widely used in different industries and consumer

applications. In this regard, the reaction of an organic acid with an alcohol lead to the

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