Time temperature superposition-时温等效原理-国外教学PPT

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Part 1: Step 1
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Importance of time-temperature superposition
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What is time-temperature superposition ?
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Time-temperature superposition is a tool to determine material properties over broad range of times and temperatures by shifting data. Material properties should be temperature dependent such as creep compliance, relaxation modulus, loss and storage moduli, viscosity etc. A material to which this technique is applicable are said to be ‘thermorheologically simple’. This terminology was introduced by Schwarzl and Staverman.
Part 1: Step 1
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Importance of time-temperature superposition
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What is the importance of time-temperature superposition ?
Any instrument, due to its mechanical limitations can usually give data over a limited range of time or frequency at a particular temperature, and this is inadequate to determine viscoelastic properties at very large time scale or at very low frequency. Therefore, in order to probe the viscoelastic properties of the material at extreme time scales, time temperature superposition principle is needed.
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A+B
T = 110o C
Conversion = 70%
C
Time of reaction = 2 hrs
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More than two hour s
A+B
T = 60o C
Conversion = 70%
C
Time of reaction = ???
Less than two hours
Prior viewing: Creep and stress relaxation Future viewing: Linear viscoelastic superposition Course Name: Polymeric Materials Level(UG/PG): PG
Author: Manish Gupta, MTech student, IIT Madras Mentor: Dr. Abhijit P. Deshpande
Part 1: step 1,2 and 3:
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Action As shown in animation Description of the action 1. 2. Picture should appear one after another as shown in the slides. Maroon call out ( in slide 1) should appear in sync with the sentence highlighted in red in audio narration para 3. Green call out ( in slide 1) should appear in sync with the sentence highlighted in pink in para 3. In slide 2, both yellow and pink item should appear in sync with sentence highlighted in green in audio narration para 5. In slide 2, green box should appear when narrator is narrating the sentence of para 7 highlighted in blue. Audio Narration 1. To understand the principle of time temperature superposition, let me start with a chemical reaction as an analogy. Consider a chemical reaction between A and B which gives C as a product. Let us assume that this reaction is taking place at one hundred and ten degree Celsius for two hours, and conversion is seventy percent. If I ask you to achieve the same conversion, with the reaction temperature of sixty degree Celsius, then naturally you will have to wait for longer time. Time require to complete the reaction will definitely be more than two hours. Similarly, when reaction is carried out at temperature higher than one hundred and ten degree Celsius, time of reaction decreases. It means that the same conversion can be obtain at different combinations of temperature and time of reaction. If the desired conversion is


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Definitions and Keywords
1. Time-temperature superposition: Time-temperature superposition is a tool to determine the material properties over broad range of times and temperatures‫‏‬by shifting data.
2. Shift factor: It is the factor by which data need to be shifted. 3. Storage modulus (G’): It describes the elastic or energy storage behavior of the material. 4. Relaxation modulus (E): It is defined as the ratio of stress (a function of time) to constant strain.
A+B
T = 150o C
Conversion = 70%
C
Time of reaction = ???
Part 1: Step 1
Baidu Nhomakorabea
Slide 2
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Importance of time-temperature superposition
1.1 Temperature = 110o C
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A+B
C
Conversion = 70% Time of reaction = 2 hrs
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If the desired conversion is 80%, then this conversion can be obtained either by
Temperature
or Time of reaction = 2 hrs
Temperature = 110o C
Time of reaction
A+B
C
Conversion = 70% Time of reaction = 2 hrs
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Temperature
Time of reaction = 2 hrs or Temperature = 110o C Time of reaction
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Part 1: Step 1
Slide 1
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Importance of time-temperature superposition
Analogously, polymer behavior obtained at a particular combination of time (or frequency) and temperature, can also be obtained at some other combinations of time ( or frequency) and temperature. And, the technique used for this purpose is known as time-temperature superposition.
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Time temperature superposition
2 G(t,T) vs. t
T TS
G(at t,To) vs. at t
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Where,
G t T To at is modulus is time is temperature is reference temperature is horizontal shift factor
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Learning objectives

After interacting with this Learning Object, the learner will be able to:

Appreciate the concept of time temperature superposition principle. Calculate shift factor. Predict material properties at extremely low and high time scales.
Time-temperature superposition
Time-temperature superposition is a tool to determine the material properties over broad range of times and temperatures‫‏‬by shifting data.
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Master Layout
This animation consists of three parts: Part 1: Importance of time-temperature superposition (TTS) Part 2: Time-temperature superposition in frequency domain Part 3: Time-temperature superposition in time domain Part 4: Calculation of shift factor 1.1 Temperature = 110o C