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Lernmaterialien für Polymer Materials an der Hochschule Aalen

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TESTE DEIN WISSEN

Name the individual steps of ‘proper waste management’. In which three groups is the content of the ‘yellow bag’ in Germany devided up for further processing?

Lösung anzeigen
TESTE DEIN WISSEN

- proper waste management:

--> collection --> pre-treatment, sorting, cleaning, after-treatment --> Recovery: material and energy recovery --> recycling

- yellow bag: metals are sorted out --> PE extraction --> PP extraction --> energy extraction 

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TESTE DEIN WISSEN

What are the consequences of ‘improper plastic waste management’?

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TESTE DEIN WISSEN

- GHG emission

- pollution

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TESTE DEIN WISSEN

Describe in brief words the term “marine litter”, the problems which are caused by it and mention at least five measures how to overcome/minimize the problem.

Lösung anzeigen
TESTE DEIN WISSEN

- marine litter --> pollution in the sea

- recycling

- less consumption

- landfill (Deponie)

- energy extraction

- substitution of most common products with biodegratables (Bio. Abbaubarkeit)

Lösung ausblenden
TESTE DEIN WISSEN

Thermosets start decomposing (Zersetzung) at TD; what comes prior to TD when the material is being heated up, TG or TM ?

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TESTE DEIN WISSEN

- TG knapp vor TD

- TM existiert nicht

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TESTE DEIN WISSEN

Chemical Bonds 

The length of different C – C – bonds are: 0.135 nm; 0.140 nm and 0.120 nm 

The bond energies are: 528, 402 and 427 (in kJ/mol) 

Please assign these figures to the C-C single, double and triple bond? 

Why is the bond energy of C-F (460 kJ/mol) higher than the bond energy of C-Cl (280 kJ/mol)?  

Keeping in mind that the C-O – bond has a bond energy of 295 kJ/mol, please explain why PTFE is not able to undergo an ageing process by oxidization.

Lösung anzeigen
TESTE DEIN WISSEN

 

Bond energy [kJ/mol]

Bond length [nm]

C-C

402

0,140

C=C

427

0,135

C≡C

528

0,120










- C-F has a shorter bond length, therefore a higher bond energy compared to C-Cl

- Flouropolymers can not age by oxidization, because the bond energy of C-F (460 kJ/mol) is much higher than the bond energy of C-O (295 kJ/mol)

Lösung ausblenden
TESTE DEIN WISSEN

By using PPs of different molecular weight (MW = molecular weight, MFR = Melt flow ratio), please describe the influence of MW onto: Mechanical performance of the finished parts: Tensile impact strength and strain at failure

Lösung anzeigen
TESTE DEIN WISSEN

Hohes Molekulargewicht -> Mehr Verschlaufungen und Valenzbindungen -> Höhere Zugfestigkeit 

Hohes MW ->Mehr amorphe Regionen -> Amorphe Bereiche verbessern Zähigkeit -> Höhere Kerbschlagzähigkeit

Lösung ausblenden
TESTE DEIN WISSEN

PTFE is a semi-crystalline polymer material which consists of appr. 1/3 amorphous regions and 2/3 crystalline regions after having gone through the sintering process. Describe the different ways how the degree of crystallinity of a sintered PTFE product can be influenced. What is the contribution (Beitrag) of the polymer manufacturer to it?

Lösung anzeigen
TESTE DEIN WISSEN

They choose of emulsion or suspension PTFE:


emulsion PTFE

  • higher amorphous content
  • better for use in flex-fatigue applications due to more free volumes in the polymer


suspension PTFE

  • higher crystalline content
  • better barrier properties

good for low permeation applications

Lösung ausblenden
TESTE DEIN WISSEN

PTFE is a semi-crystalline polymer material which consists of appr. 1/3 amorphous regions and 2/3 crystalline regions after having gone through the sintering process. Describe the different ways how the degree of crystallinity of a sintered PTFE product can be influenced. What is the contribution (Beitrag) of the processor to it?


Lösung anzeigen
TESTE DEIN WISSEN

mainly cooling speed:

 

slow cooling speed

  • higher cryst content 
  • better barrier properties

fast cooling speed

  • high amorphous content 

               good flex fatigue properties

Lösung ausblenden
TESTE DEIN WISSEN

Please characterize the amorphous state of polymer materials by mentioning of at least five characteristic properties of it.

Lösung anzeigen
TESTE DEIN WISSEN

- translucent 

- sehr niedeige Schwindung beim Abkühlen

- Keine Änderung des Brechungsindex (alles amorph)

- Keine Diffuse Streuung von Licht (bei einer Wellenlänge von 0,4 - 0,7 mm)

- Keine Gleichmäßige Anordnung der Orientierung (Hohe Entropie)

Lösung ausblenden
TESTE DEIN WISSEN

In order to describe the overall energy status of a material or phase, the Gibbs-Helmholtz Equation is used:  ΔG = ΔH – T •ΔS.  This equation is also applicable to semi-

crystalline polymers. The state of equilibrium is always the state characterized by the lowest value for the Free Gibb’s Enthalpy, G. 

Please explain, what stands behind H, T, S, U , p and V and how they contribute to G. Under energy considerations, please explain how the structure of the polymer must look like, that the formation of crystallites is very likely. Which kind of bonds drives the formation of crystallites forward? 

Lösung anzeigen
TESTE DEIN WISSEN

-H = Enthalpy              --> bonding energy

-T = Temperature

-S = Entropy                --> all kinetic energy of moving particles

-U = Internal energy    --> chemical bonding energy

-p = pressure

-V = Volume change


- low cooling speed --> hight T -->low ΔG 

- side chains prohibit the formation of cryst

- regular spaced substituents

Lösung ausblenden
TESTE DEIN WISSEN

.) Flow-induced nucleation may form another kind of semi-crystalline polymer. How is it called, what are its benefits for the polymer properties and how looks the structure like? How do we have to set the processing parameters to support flow-induced crystallization? How can we delete this polymer structure again?

Lösung anzeigen
TESTE DEIN WISSEN

Shish-Kebab Struktur

Überstruktur 

-stark erhöhte mechanische Kennwerte

-geringe Kriechneigung in Extrusionsrichtung

-hohe Wärmeformbeständigkeit

-hohe mechanische Festigkeit 

-low melt temperature + high pressure 

-high viscosity, high shear 

-elongation + orientation of polymer

-destroyable by re-melting


Lösung ausblenden
TESTE DEIN WISSEN

Considering the service temperature range (STR) of polymer materials, please define the position of TG and TM for semi-crystalline polymers and amorphous polymers.

Lösung anzeigen
TESTE DEIN WISSEN

Amorphous - Service Temperature range under Tg (Melting at TG)

Semi-Chry. - Service Temp. Range up to TM

Lösung ausblenden
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Q:

Name the individual steps of ‘proper waste management’. In which three groups is the content of the ‘yellow bag’ in Germany devided up for further processing?

A:

- proper waste management:

--> collection --> pre-treatment, sorting, cleaning, after-treatment --> Recovery: material and energy recovery --> recycling

- yellow bag: metals are sorted out --> PE extraction --> PP extraction --> energy extraction 

Q:

What are the consequences of ‘improper plastic waste management’?

A:

- GHG emission

- pollution

Q:

Describe in brief words the term “marine litter”, the problems which are caused by it and mention at least five measures how to overcome/minimize the problem.

A:

- marine litter --> pollution in the sea

- recycling

- less consumption

- landfill (Deponie)

- energy extraction

- substitution of most common products with biodegratables (Bio. Abbaubarkeit)

Q:

Thermosets start decomposing (Zersetzung) at TD; what comes prior to TD when the material is being heated up, TG or TM ?

A:

- TG knapp vor TD

- TM existiert nicht

Q:

Chemical Bonds 

The length of different C – C – bonds are: 0.135 nm; 0.140 nm and 0.120 nm 

The bond energies are: 528, 402 and 427 (in kJ/mol) 

Please assign these figures to the C-C single, double and triple bond? 

Why is the bond energy of C-F (460 kJ/mol) higher than the bond energy of C-Cl (280 kJ/mol)?  

Keeping in mind that the C-O – bond has a bond energy of 295 kJ/mol, please explain why PTFE is not able to undergo an ageing process by oxidization.

A:

 

Bond energy [kJ/mol]

Bond length [nm]

C-C

402

0,140

C=C

427

0,135

C≡C

528

0,120










- C-F has a shorter bond length, therefore a higher bond energy compared to C-Cl

- Flouropolymers can not age by oxidization, because the bond energy of C-F (460 kJ/mol) is much higher than the bond energy of C-O (295 kJ/mol)

Mehr Karteikarten anzeigen
Q:

By using PPs of different molecular weight (MW = molecular weight, MFR = Melt flow ratio), please describe the influence of MW onto: Mechanical performance of the finished parts: Tensile impact strength and strain at failure

A:

Hohes Molekulargewicht -> Mehr Verschlaufungen und Valenzbindungen -> Höhere Zugfestigkeit 

Hohes MW ->Mehr amorphe Regionen -> Amorphe Bereiche verbessern Zähigkeit -> Höhere Kerbschlagzähigkeit

Q:

PTFE is a semi-crystalline polymer material which consists of appr. 1/3 amorphous regions and 2/3 crystalline regions after having gone through the sintering process. Describe the different ways how the degree of crystallinity of a sintered PTFE product can be influenced. What is the contribution (Beitrag) of the polymer manufacturer to it?

A:

They choose of emulsion or suspension PTFE:


emulsion PTFE

  • higher amorphous content
  • better for use in flex-fatigue applications due to more free volumes in the polymer


suspension PTFE

  • higher crystalline content
  • better barrier properties

good for low permeation applications

Q:

PTFE is a semi-crystalline polymer material which consists of appr. 1/3 amorphous regions and 2/3 crystalline regions after having gone through the sintering process. Describe the different ways how the degree of crystallinity of a sintered PTFE product can be influenced. What is the contribution (Beitrag) of the processor to it?


A:

mainly cooling speed:

 

slow cooling speed

  • higher cryst content 
  • better barrier properties

fast cooling speed

  • high amorphous content 

               good flex fatigue properties

Q:

Please characterize the amorphous state of polymer materials by mentioning of at least five characteristic properties of it.

A:

- translucent 

- sehr niedeige Schwindung beim Abkühlen

- Keine Änderung des Brechungsindex (alles amorph)

- Keine Diffuse Streuung von Licht (bei einer Wellenlänge von 0,4 - 0,7 mm)

- Keine Gleichmäßige Anordnung der Orientierung (Hohe Entropie)

Q:

In order to describe the overall energy status of a material or phase, the Gibbs-Helmholtz Equation is used:  ΔG = ΔH – T •ΔS.  This equation is also applicable to semi-

crystalline polymers. The state of equilibrium is always the state characterized by the lowest value for the Free Gibb’s Enthalpy, G. 

Please explain, what stands behind H, T, S, U , p and V and how they contribute to G. Under energy considerations, please explain how the structure of the polymer must look like, that the formation of crystallites is very likely. Which kind of bonds drives the formation of crystallites forward? 

A:

-H = Enthalpy              --> bonding energy

-T = Temperature

-S = Entropy                --> all kinetic energy of moving particles

-U = Internal energy    --> chemical bonding energy

-p = pressure

-V = Volume change


- low cooling speed --> hight T -->low ΔG 

- side chains prohibit the formation of cryst

- regular spaced substituents

Q:

.) Flow-induced nucleation may form another kind of semi-crystalline polymer. How is it called, what are its benefits for the polymer properties and how looks the structure like? How do we have to set the processing parameters to support flow-induced crystallization? How can we delete this polymer structure again?

A:

Shish-Kebab Struktur

Überstruktur 

-stark erhöhte mechanische Kennwerte

-geringe Kriechneigung in Extrusionsrichtung

-hohe Wärmeformbeständigkeit

-hohe mechanische Festigkeit 

-low melt temperature + high pressure 

-high viscosity, high shear 

-elongation + orientation of polymer

-destroyable by re-melting


Q:

Considering the service temperature range (STR) of polymer materials, please define the position of TG and TM for semi-crystalline polymers and amorphous polymers.

A:

Amorphous - Service Temperature range under Tg (Melting at TG)

Semi-Chry. - Service Temp. Range up to TM

Polymer Materials

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