14
1
phenolic resins and epoxy resins have this property. Similarly,
there is a need for carbon fibres with high thermal stability.
Pitch- or rayon-based carbon fibres have high thermal stability.
High charring content of resin causes high residual carbon
mass in the composite; therefore, the number of cycles for
saturating the composite with phenolic resin for densification
of the matrix is reduced. This makes the process time short.
Nose cones of hypersonic rockets and reentry vehicles are
made out of CCC.
Polymeric composites are the most popular among all the composites. They use glass fibres, carbon fibres, Kevlar fibres, polyolefin
fibres, natural fibres, etc. as reinforcements and a host of polymers
(such as epoxy resin, polyester resin, polyamides, polyimides, polypropylene, etc.) as a matrix. Reinforced thermoplastics are the most
rapidly growing class of composites. In this class, the focus is on
improving the properties of the resin to allow these materials to
perform well in new applications where conventional materials
were used previously. Polymeric composites have versatility in
terms of hybrid construction, wherein different types of reinforcements in the composite result in a range of properties that cater to
the different needs of end-use applications. Today, polymer matrix
composites find applications in every walk of life (such as aerospace, automotives, locomotives, marine, sports goods, household
appliances, construction, oil and gas, electronics, etc.).
It is evident from this discussion that the two key components
of an advanced polymeric composite are resin matrix and reinforcement. The types of resin matrices are thermosetting and thermoplastic matrices. Thermosetting matrices are epoxy resin, unsaturated
polyester resin, phenolic resin, vinyl ester resin, polyimide resin,
etc. They are solidified after the application of heat and are not
deformable after curing as they form a 3-D cross-link structure. The
most widely used resin matrix for advanced composites is thermosetting epoxy resin. Other thermosetting resins, such as bismaleimides and polyimides, are finding increasing applications in
high-temperature environments. Thermoplastic matrices may be
semi-crystalline, crystalline, or amorphous in morphology. In the
former type, the semi-crystalline or crystalline morphology may be
significantly influenced by the reinforcement, which may or may
not act as nucleating agent. Today, the use of thermoplastic resins is
comparatively much less than that of thermosetting resins in
advanced composites. However, inherent toughness and potential
recycling capabilities of thermoplastics have increased industry’s
interest in these resins. Some of the major thermoplastic resins
which are being evaluated for advanced polymer composites
include polyamide-imides (PAl), polyether ether ketone (PEEK),
polyetherimides (PEI), polyether sulfones (PES), and polyphenylene sulphides (PPS).
Fillers show reinforcement characteristics depending upon the
aspect ratio of the filler and the interphase interaction. In many
cases, the treatment of fillers with coupling agents results into a
chemical bonding between the filler and the polymer matrix. This
Chapter 1 · Introduction
1
phenolic resins and epoxy resins have this property. Similarly,
there is a need for carbon fibres with high thermal stability.
Pitch- or rayon-based carbon fibres have high thermal stability.
High charring content of resin causes high residual carbon
mass in the composite; therefore, the number of cycles for
saturating the composite with phenolic resin for densification
of the matrix is reduced. This makes the process time short.
Nose cones of hypersonic rockets and reentry vehicles are
made out of CCC.
Polymeric composites are the most popular among all the composites. They use glass fibres, carbon fibres, Kevlar fibres, polyolefin
fibres, natural fibres, etc. as reinforcements and a host of polymers
(such as epoxy resin, polyester resin, polyamides, polyimides, polypropylene, etc.) as a matrix. Reinforced thermoplastics are the most
rapidly growing class of composites. In this class, the focus is on
improving the properties of the resin to allow these materials to
perform well in new applications where conventional materials
were used previously. Polymeric composites have versatility in
terms of hybrid construction, wherein different types of reinforcements in the composite result in a range of properties that cater to
the different needs of end-use applications. Today, polymer matrix
composites find applications in every walk of life (such as aerospace, automotives, locomotives, marine, sports goods, household
appliances, construction, oil and gas, electronics, etc.).
It is evident from this discussion that the two key components
of an advanced polymeric composite are resin matrix and reinforcement. The types of resin matrices are thermosetting and thermoplastic matrices. Thermosetting matrices are epoxy resin, unsaturated
polyester resin, phenolic resin, vinyl ester resin, polyimide resin,
etc. They are solidified after the application of heat and are not
deformable after curing as they form a 3-D cross-link structure. The
most widely used resin matrix for advanced composites is thermosetting epoxy resin. Other thermosetting resins, such as bismaleimides and polyimides, are finding increasing applications in
high-temperature environments. Thermoplastic matrices may be
semi-crystalline, crystalline, or amorphous in morphology. In the
former type, the semi-crystalline or crystalline morphology may be
significantly influenced by the reinforcement, which may or may
not act as nucleating agent. Today, the use of thermoplastic resins is
comparatively much less than that of thermosetting resins in
advanced composites. However, inherent toughness and potential
recycling capabilities of thermoplastics have increased industry’s
interest in these resins. Some of the major thermoplastic resins
which are being evaluated for advanced polymer composites
include polyamide-imides (PAl), polyether ether ketone (PEEK),
polyetherimides (PEI), polyether sulfones (PES), and polyphenylene sulphides (PPS).
Fillers show reinforcement characteristics depending upon the
aspect ratio of the filler and the interphase interaction. In many
cases, the treatment of fillers with coupling agents results into a
chemical bonding between the filler and the polymer matrix. This
Chapter 1 · Introduction