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9
nologies, and processing parameters. There are two types of
approaches for sample preparation: bottom-up and top-down.
1. Bottom-Up Approach—In this approach, the sample is moulded
or fabricated directly into its final shape or configuration from
raw materials. For example, injection-moulded thermoplastic
composite samples are moulded in a matched die mould using
compression moulding technology or VARTM. These samples
have very high dimensional accuracies.
2. Top-Down Approach—In this approach, a composite test
laminate is fabricated using any of the processes mentioned in
7 Chaps. 5 and 6. These test laminates are further machined to
the dimension of the test samples per their standards. These
machining operations may vary from manual cutting by
hacksaw to milling, turning, honing, grinding, etc. The
secondary machining operations expose the machined surface
of the composite to the environment. These secondary operations—more often than not—are manual operations that
sometimes cause defects in the composite test sample. For
making samples for SEM and TEM where the morphology of a
fractured or desired bulk surface need to be studied, this is the
only suitable approach.
9.2 Characterisation
The characterization of any material is established based on its morphology or molecular structure. It’s charcterization is an intrinsic
property of the material. In the case of polymers, character is established based on the properties of polymeric molecules, interphase,
and physical form of reinforcement.
9.2.1 Thermal Characterization
Thermal analysis has a unique role in the characterization of polymeric composites. This is effectively used for measuring various
morphological and structural transitions in a polymeric composite
with respect to temperature. The most important structural transitions are the glass transition temperature, crystallization, melting
temperature, heat absorption, evolution, and degradation. Thermal
characterization may be carried out rapidly and reveals the very
basic nature of the polymeric composite [3–5].
1. Differential Scanning Calorimetry (DSC)—DSC provides both
quantitative and qualitative data on the material. This technique may be used under a wide variety of conditions, such as
different heating rates, different sample sizes, testing medium
(air or inert gas), and sensitivity. This is carried out as per
ASTM D3418 at a selected heating rate. In DSC, the sample
and reference materials are heated to the same temperature,
and their temperature is kept the same at any time. The peaks
in a DSC thermogram are generated due to thermodynamic
changes, releasing or absorbing heat measured in mcal. The
9.2 · Characterisation
9
nologies, and processing parameters. There are two types of
approaches for sample preparation: bottom-up and top-down.
1. Bottom-Up Approach—In this approach, the sample is moulded
or fabricated directly into its final shape or configuration from
raw materials. For example, injection-moulded thermoplastic
composite samples are moulded in a matched die mould using
compression moulding technology or VARTM. These samples
have very high dimensional accuracies.
2. Top-Down Approach—In this approach, a composite test
laminate is fabricated using any of the processes mentioned in
7 Chaps. 5 and 6. These test laminates are further machined to
the dimension of the test samples per their standards. These
machining operations may vary from manual cutting by
hacksaw to milling, turning, honing, grinding, etc. The
secondary machining operations expose the machined surface
of the composite to the environment. These secondary operations—more often than not—are manual operations that
sometimes cause defects in the composite test sample. For
making samples for SEM and TEM where the morphology of a
fractured or desired bulk surface need to be studied, this is the
only suitable approach.
9.2 Characterisation
The characterization of any material is established based on its morphology or molecular structure. It’s charcterization is an intrinsic
property of the material. In the case of polymers, character is established based on the properties of polymeric molecules, interphase,
and physical form of reinforcement.
9.2.1 Thermal Characterization
Thermal analysis has a unique role in the characterization of polymeric composites. This is effectively used for measuring various
morphological and structural transitions in a polymeric composite
with respect to temperature. The most important structural transitions are the glass transition temperature, crystallization, melting
temperature, heat absorption, evolution, and degradation. Thermal
characterization may be carried out rapidly and reveals the very
basic nature of the polymeric composite [3–5].
1. Differential Scanning Calorimetry (DSC)—DSC provides both
quantitative and qualitative data on the material. This technique may be used under a wide variety of conditions, such as
different heating rates, different sample sizes, testing medium
(air or inert gas), and sensitivity. This is carried out as per
ASTM D3418 at a selected heating rate. In DSC, the sample
and reference materials are heated to the same temperature,
and their temperature is kept the same at any time. The peaks
in a DSC thermogram are generated due to thermodynamic
changes, releasing or absorbing heat measured in mcal. The
9.2 · Characterisation