I have a copolymer if epoxy and rubber reinforced with Sic. I want a standard FTIR figure in transmittance mode.
Applications of FTIR on Epoxy Resins –
Identification, Monitoring the Curing
Process, Phase Separation and Water Uptake
María González González, Juan Carlos Cabanelas and Juan Baselga
University Carlos III of Madrid
Spain
1. Introduction
Epoxy resins are a family of thermosetting materials widely used as adhesives, coatings and
matrices in polymer composites because of the low viscosity of the formulations, good
insulating properties of the final material even at high temperatures and good chemical and
thermal resistance (May, 1988). Epoxy thermosets can be described as 3D polymer networks
formed by the chemical reaction between monomers (“curing”). This 3D covalent network
structure determines the properties of thermosetting polymers: unlike thermoplastics, this
kind of polymers does not melt, and once the network has been formed the material cannot
be reprocessed. Maybe one of the main advantages of epoxy thermosets is that the starting
monomers have low viscosity so that complex geometries can be easily shaped and fixed
after curing the monomers. Thus the formation of the network via chemical reaction is a key
aspect in this kind of materials.
Epoxy formulations usually include more than one component, although there are different
crosslinking mechanisms involving either chemical reaction between one single type of
monomer (homopolymerization) or two kinds of monomers with different functional
groups. In both cases, a common constituent is always found: the epoxy monomer. The
main feature of the epoxy monomer is the oxirane functional group, which is a three
member ring formed between two carbon atoms and an oxygen, as shown in Figure 1. This
atomic arrangement shows enhanced reactivity when compared with common ethers
because of its high strain. Due to the different electronegativity of carbon and oxygen, the
carbon atoms of the ring are electrophilic. Thus epoxies can undergo ring opening reactions
towards nucleophiles. The polarity of the oxirane ring makes possible detection by IR
spectroscopy.
There are mainly two families of epoxies: the glycidyl epoxies and non-glycidyl epoxies
(also called aliphatic or cycloaliphatic epoxy resins). The absence of aromatic rings in
aliphatic epoxies makes them UV resistant and suitable for outdoor applications and also
reduces viscosity. The most common epoxy monomers of each family are diglycidylether of
bisphenol A (known as DGEBA) and 3,4-Epoxycyclohexyl-3’4’-epoxycyclohexane
carboxylate (ECC) respectively and their structures are given in Figure 2 (a, b).
Cycloaliphatic resins are usually found in the form of pure chemicals with a definite
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Infrared Spectroscopy – Materials Science, Engineering and Technology
262
Fig. 1. Oxirane ring
Fig. 2. Chemical structures of common epoxy resins: a) 2,2-Bis[4-(glycidy
Dear researcher
It will be appreciated if you have a specific figure of epoxy / polysufide reinforced with Sic.
Thanks in advance
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