Differential scanning calorimetry (DSC) measures the difference in the heat required to increase or maintain the temperature of a sample and reference, giving the difference in energy required as heat flow or heat flux. Chemical reactions and many physical transitions (for example, melting or crystallization) will be exothermic or endothermic. Such transitions will show as either peaks or troughs when heat flow is plotted against temperature (for dynamic experiments over a range of temperatures) or time (for isothermal studies), as more or less heat will be required to maintain sample temperature. DSC can be adapted so that the sample and reference cells are irradiated with a light-source split by a bifurcated light guide, allowing accurate monitoring of exothermic photo-polymerization reactions, which will have a negative heat flow. Integration of the curve can be used to calculate the enthalpy of polymerization and related to overall conversion of monomer vinyl groups.1 DSC can also be
used to monitor the acid-base neutralization component of the setting in glass-ionomer cements (which will also be exothermic), with the time taken for the heat flow to return to the baseline being a measure of the total time for the cement to fully set.2 It should be noted that
the polymerization and ionic setting reactions will occur concurrently, and will be indistinguishable by DSC.
3.2.2 Photo-Rheology
Rheology is the study of deformation of a material upon the application of a force, with the type of deformation depending on the state of material the force acts on. For example, a liquid would be expected to flow when a force is applied with the energy dissipated as heat, displaying viscous properties, whereas many solids will deform before regaining their shape
present and discuss measurements relating to such properties, some treatment of the theory of viscoelastic behaviour and oscillatory rheology measurements is necessary.
Stress and Strain
Anresulting force. A diagram for this deformation, called simple shear, is shown in one plate moves a distance d
dimensionless and usually expressed as a percentage. The velocity of the plate the shear rate can be written as d(d
this deformation on the material, alternatively it can be thought of as the material exerting a force on the moving plate. Total force will depend on the area of the plate in contact with the sample (A), and is
Figure
Viscosity and moduli
The viscosity of a liquid can be defined as the ratio of relation (
strain
Equation
present and discuss measurements relating to such properties, some treatment of the theory of viscoelastic behaviour and oscillatory rheology measurements is necessary.
Stress and Strain
n oscillatingresulting force. A diagram for this deformation, called simple shear, is shown in one plate moves a distance d
dimensionless and usually expressed as a percentage. The velocity of the plate the shear rate can be written as d(d
this deformation on the material, alternatively it can be thought of as the material exerting a force on the moving plate. Total force will depend on the area of the plate in contact with the sample (A), and is
Figure
Viscosity and moduli
The viscosity of a liquid can be defined as the ratio of relation (
strain
Equation
present and discuss measurements relating to such properties, some treatment of the theory of viscoelastic behaviour and oscillatory rheology measurements is necessary.
Stress and Strain
oscillatingresulting force. A diagram for this deformation, called simple shear, is shown in one plate moves a distance d
dimensionless and usually expressed as a percentage. The velocity of the plate the shear rate can be written as d(d
this deformation on the material, alternatively it can be thought of as the material exerting a force on the moving plate. Total force will depend on the area of the plate in contact with the sample (A), and is
Figure 3.1
Viscosity and moduli
The viscosity of a liquid can be defined as the ratio of relation (
strain (Equation
Equation
present and discuss measurements relating to such properties, some treatment of the theory of viscoelastic behaviour and oscillatory rheology measurements is necessary.
Stress and Strain
oscillatingresulting force. A diagram for this deformation, called simple shear, is shown in one plate moves a distance d
dimensionless and usually expressed as a percentage. The velocity of the plate the shear rate can be written as d(d
this deformation on the material, alternatively it can be thought of as the material exerting a force on the moving plate. Total force will depend on the area of the plate in contact with the sample (A), and is
1: Diagram of simple shear flow between two parallel plates.
Viscosity and moduli
The viscosity of a liquid can be defined as the ratio of relation (Equation
Equation
Equation 3.1: Newton's relation, where
present and discuss measurements relating to such properties, some treatment of the theory of viscoelastic behaviour and oscillatory rheology measurements is necessary.
Stress and Strain
oscillatingresulting force. A diagram for this deformation, called simple shear, is shown in one plate moves a distance d
dimensionless and usually expressed as a percentage. The velocity of the plate the shear rate can be written as d(d
this deformation on the material, alternatively it can be thought of as the material exerting a force on the moving plate. Total force will depend on the area of the plate in contact with the sample (A), and is
: Diagram of simple shear flow between two parallel plates.
Viscosity and moduli
The viscosity of a liquid can be defined as the ratio of Equation
Equation
: Newton's relation, where
present and discuss measurements relating to such properties, some treatment of the theory of viscoelastic behaviour and oscillatory rheology measurements is necessary.
Stress and Strain
oscillating rotational rheometer will subject the sample to a displacement and measure the resulting force. A diagram for this deformation, called simple shear, is shown in
one plate moves a distance d
dimensionless and usually expressed as a percentage. The velocity of the plate the shear rate can be written as d(d
this deformation on the material, alternatively it can be thought of as the material exerting a force on the moving plate. Total force will depend on the area of the plate in contact with the sample (A), and is
: Diagram of simple shear flow between two parallel plates.
Viscosity and moduli
The viscosity of a liquid can be defined as the ratio of Equation
Equation 3
: Newton's relation, where
present and discuss measurements relating to such properties, some treatment of the theory of viscoelastic behaviour and oscillatory rheology measurements is necessary.
Stress and Strain
rotational rheometer will subject the sample to a displacement and measure the resulting force. A diagram for this deformation, called simple shear, is shown in
one plate moves a distance d
dimensionless and usually expressed as a percentage. The velocity of the plate the shear rate can be written as d(d
this deformation on the material, alternatively it can be thought of as the material exerting a force on the moving plate. Total force will depend on the area of the plate in contact with the sample (A), and isthus considered as force per unit area, or stress, σ.
: Diagram of simple shear flow between two parallel plates.
Viscosity and moduli
The viscosity of a liquid can be defined as the ratio of Equation 3
3.2):
: Newton's relation, where
present and discuss measurements relating to such properties, some treatment of the theory of viscoelastic behaviour and oscillatory rheology measurements is necessary.
Stress and Strain
rotational rheometer will subject the sample to a displacement and measure the resulting force. A diagram for this deformation, called simple shear, is shown in
one plate moves a distance d
dimensionless and usually expressed as a percentage. The velocity of the plate the shear rate can be written as d(d
this deformation on the material, alternatively it can be thought of as the material exerting a force on the moving plate. Total force will depend on the area of the plate in contact with the
thus considered as force per unit area, or stress, σ.
: Diagram of simple shear flow between two parallel plates.
Viscosity and moduli
The viscosity of a liquid can be defined as the ratio of
3.1) and, similarly, the modulus of a solid is defined as ):
: Newton's relation, where
present and discuss measurements relating to such properties, some treatment of the theory of viscoelastic behaviour and oscillatory rheology measurements is necessary.
rotational rheometer will subject the sample to a displacement and measure the resulting force. A diagram for this deformation, called simple shear, is shown in
one plate moves a distance d
dimensionless and usually expressed as a percentage. The velocity of the plate the shear rate can be written as d(d
this deformation on the material, alternatively it can be thought of as the material exerting a force on the moving plate. Total force will depend on the area of the plate in contact with the
thus considered as force per unit area, or stress, σ.
: Diagram of simple shear flow between two parallel plates.
Viscosity and moduli
The viscosity of a liquid can be defined as the ratio of
) and, similarly, the modulus of a solid is defined as
: Newton's relation, where
present and discuss measurements relating to such properties, some treatment of the theory of viscoelastic behaviour and oscillatory rheology measurements is necessary.
rotational rheometer will subject the sample to a displacement and measure the resulting force. A diagram for this deformation, called simple shear, is shown in
one plate moves a distance d
dimensionless and usually expressed as a percentage. The velocity of the plate the shear rate can be written as d(d
this deformation on the material, alternatively it can be thought of as the material exerting a force on the moving plate. Total force will depend on the area of the plate in contact with the
thus considered as force per unit area, or stress, σ.
: Diagram of simple shear flow between two parallel plates.
The viscosity of a liquid can be defined as the ratio of
) and, similarly, the modulus of a solid is defined as
: Newton's relation, where
present and discuss measurements relating to such properties, some treatment of the theory of viscoelastic behaviour and oscillatory rheology measurements is necessary.
rotational rheometer will subject the sample to a displacement and measure the resulting force. A diagram for this deformation, called simple shear, is shown in
one plate moves a distance dx, the sample has been subjected to a strain, γ = d
dimensionless and usually expressed as a percentage. The velocity of the plate the shear rate can be written as d(d
this deformation on the material, alternatively it can be thought of as the material exerting a force on the moving plate. Total force will depend on the area of the plate in contact with the
thus considered as force per unit area, or stress, σ.
: Diagram of simple shear flow between two parallel plates.
The viscosity of a liquid can be defined as the ratio of
) and, similarly, the modulus of a solid is defined as
: Newton's relation, where
present and discuss measurements relating to such properties, some treatment of the theory of viscoelastic behaviour and oscillatory rheology measurements is necessary.
rotational rheometer will subject the sample to a displacement and measure the resulting force. A diagram for this deformation, called simple shear, is shown in
, the sample has been subjected to a strain, γ = d
dimensionless and usually expressed as a percentage. The velocity of the plate the shear rate can be written as d(d
this deformation on the material, alternatively it can be thought of as the material exerting a force on the moving plate. Total force will depend on the area of the plate in contact with the
thus considered as force per unit area, or stress, σ.
: Diagram of simple shear flow between two parallel plates.
The viscosity of a liquid can be defined as the ratio of
) and, similarly, the modulus of a solid is defined as
: Newton's relation, whereη
present and discuss measurements relating to such properties, some treatment of the theory of viscoelastic behaviour and oscillatory rheology measurements is necessary.
rotational rheometer will subject the sample to a displacement and measure the resulting force. A diagram for this deformation, called simple shear, is shown in
, the sample has been subjected to a strain, γ = d
dimensionless and usually expressed as a percentage. The velocity of the plate the shear rate can be written as d(dx/d
this deformation on the material, alternatively it can be thought of as the material exerting a force on the moving plate. Total force will depend on the area of the plate in contact with the
thus considered as force per unit area, or stress, σ.
: Diagram of simple shear flow between two parallel plates.
The viscosity of a liquid can be defined as the ratio of
) and, similarly, the modulus of a solid is defined as
= viscosity.
present and discuss measurements relating to such properties, some treatment of the theory of viscoelastic behaviour and oscillatory rheology measurements is necessary.
rotational rheometer will subject the sample to a displacement and measure the resulting force. A diagram for this deformation, called simple shear, is shown in
, the sample has been subjected to a strain, γ = d
dimensionless and usually expressed as a percentage. The velocity of the plate /dy)/d
this deformation on the material, alternatively it can be thought of as the material exerting a force on the moving plate. Total force will depend on the area of the plate in contact with the
thus considered as force per unit area, or stress, σ.
: Diagram of simple shear flow between two parallel plates.
The viscosity of a liquid can be defined as the ratio of
) and, similarly, the modulus of a solid is defined as
= viscosity.
present and discuss measurements relating to such properties, some treatment of the theory of viscoelastic behaviour and oscillatory rheology measurements is necessary.
rotational rheometer will subject the sample to a displacement and measure the resulting force. A diagram for this deformation, called simple shear, is shown in
, the sample has been subjected to a strain, γ = d
dimensionless and usually expressed as a percentage. The velocity of the plate )/dt
this deformation on the material, alternatively it can be thought of as the material exerting a force on the moving plate. Total force will depend on the area of the plate in contact with the
thus considered as force per unit area, or stress, σ.
: Diagram of simple shear flow between two parallel plates.
The viscosity of a liquid can be defined as the ratio of
) and, similarly, the modulus of a solid is defined as
= viscosity.
present and discuss measurements relating to such properties, some treatment of the theory of viscoelastic behaviour and oscillatory rheology measurements is necessary.
rotational rheometer will subject the sample to a displacement and measure the resulting force. A diagram for this deformation, called simple shear, is shown in
, the sample has been subjected to a strain, γ = d
dimensionless and usually expressed as a percentage. The velocity of the plate t=γ
this deformation on the material, alternatively it can be thought of as the material exerting a force on the moving plate. Total force will depend on the area of the plate in contact with the
thus considered as force per unit area, or stress, σ.
: Diagram of simple shear flow between two parallel plates.
The viscosity of a liquid can be defined as the ratio of
) and, similarly, the modulus of a solid is defined as
= viscosity.
present and discuss measurements relating to such properties, some treatment of the theory of viscoelastic behaviour and oscillatory rheology measurements is necessary.
rotational rheometer will subject the sample to a displacement and measure the resulting force. A diagram for this deformation, called simple shear, is shown in
, the sample has been subjected to a strain, γ = d
dimensionless and usually expressed as a percentage. The velocity of the plate
γ. Whil
this deformation on the material, alternatively it can be thought of as the material exerting a force on the moving plate. Total force will depend on the area of the plate in contact with the
thus considered as force per unit area, or stress, σ.
: Diagram of simple shear flow between two parallel plates.
The viscosity of a liquid can be defined as the ratio of
) and, similarly, the modulus of a solid is defined as
present and discuss measurements relating to such properties, some treatment of the theory of viscoelastic behaviour and oscillatory rheology measurements is necessary.
rotational rheometer will subject the sample to a displacement and measure the resulting force. A diagram for this deformation, called simple shear, is shown in
, the sample has been subjected to a strain, γ = d
dimensionless and usually expressed as a percentage. The velocity of the plate . Whil
this deformation on the material, alternatively it can be thought of as the material exerting a force on the moving plate. Total force will depend on the area of the plate in contact with the
thus considered as force per unit area, or stress, σ.
: Diagram of simple shear flow between two parallel plates.
The viscosity of a liquid can be defined as the ratio of
) and, similarly, the modulus of a solid is defined as
present and discuss measurements relating to such properties, some treatment of the theory of viscoelastic behaviour and oscillatory rheology measurements is necessary.
rotational rheometer will subject the sample to a displacement and measure the resulting force. A diagram for this deformation, called simple shear, is shown in
, the sample has been subjected to a strain, γ = d
dimensionless and usually expressed as a percentage. The velocity of the plate
. While it takes the exertion of a force to affect this deformation on the material, alternatively it can be thought of as the material exerting a force on the moving plate. Total force will depend on the area of the plate in contact with the