Oluschinski: Created page with "{{Language_sel|LANG=ger|ARTIKEL=Adhäsive Energiefreisetzungsrate}} {{PSM_Infobox}} Adhesive energy release rate (Author: Prof. Dr. Michael Nase) FORCETOC ==General== To characterize the peel behaviour of plastic or metal films, as well as metal-plastic composites, the T-peel test based on ASTM D 1876 “Standard Test Method for Peel Resistance of Ad..."

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Created page with "{{Language_sel|LANG=ger|ARTIKEL=Adhäsive Energiefreisetzungsrate}} {{PSM_Infobox}} Adhesive energy release rate (Author: Prof. Dr. Michael Nase) __FORCETOC__ ==General== To characterize the peel behaviour of plastic or metal films, as well as metal-plastic composites, the T-peel test based on ASTM D 1876 “Standard Test Method for Peel Resistance of Ad..."

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{{Language_sel|LANG=ger|ARTIKEL=Adhäsive Energiefreisetzungsrate}}
{{PSM_Infobox}}
Adhesive energy release rate (Author: Prof. Dr. Michael Nase)
__FORCETOC__

==General==

To characterize the [[Peel Behaviour – Modelling|peel behaviour]] of [[Plastics|plastic]] or metal films, as well as metal-plastic composites, the [[T-Peel Test|T-peel test]] based on ASTM D 1876 “Standard Test Method for Peel Resistance of Adhesives (T-Peel Test)” and the [[Fixed-arm Peel Test|fixed-arm peel test]] based on the ESIS TC4 standard proposal “Peel Testing of Flexible Laminates” are available.

The methods of [[Fracture Mechanics#Linear-elastic fracture mechanics|linear-elastic fracture mechanics]] are used for the material-specific description of the [[Peeling Process|peel process]], which make it possible to derive [[Material Parameter|parameters]] with a high information content, such as the [[Energy Release Rate|energy release rate]]. Such parameters can then be advantageously used to evaluate the application behaviour of film systems.

==Evaluation of the peel behaviour of sealed films using fracture mechanics parameters==

The adhesive energy release rate ''G''aIc reflects only the amount of energy required to separate two sealed films (see: [[Sealed Seam|sealed seam]]) and is applicable to elastic-plastic material behaviour.

The adhesive energy release rate ''G''aIc is calculated according to '''Eq. (1)'''.

{|
|-
|width="20px"|
|width="500px" | <math> G_{aIc} = \frac {U_a} { W L} = \frac {E_G-E_{d,P}-E_{d,S}}{W L}</math>
|(1)
|}

with
{|
|-
|''U''a
|width="15px" |
|direct adhesion energy 
|-
|''E''G
|
|total peel energy 
|-
|''E''d,P
|
|deformation energy of the peel arm 
|-
|''E''d,S
|
|deformation energy of the peeled seal seam 
|-
|''W''
|
|width of the seal seam 
|-
|''L''
|
|length of the [[Sealed Seam|sealed seam]]
|}

The total peel energy ''E''G corresponds to the area under the [[Peel Force – Fracture Path Diagram|peel force–fracture path diagram]] (also known as the peel curve; see '''Fig. 1'''). The deformation energy of the peel arms ''E''d,P is the energy absorbed by the peel test specimen in the run-up to the actual [[Peeling Process|peel process]]. In the [[Peel Force – Fracture Path Diagram|peel force–fracture path diagram]], the start of the peel process is marked by a change in the rise of the peel curve at ''l''d,P, so that the deformation energy of the peel arm ''E''d,P corresponds to the area under the peel curve up to ''l''d,P. It is assumed that all [[Deformation|deformations]] that occur after ''l''d,P as a result of the increase in force are absorbed by the peeled seal and no longer by the peel arm, since the peeled [[Sealed Seam|seal]] has a greater tendency to deform than the peel arm.

[[File:Adhesive ERR Fig-1.jpg]]
{|
|- valign="top"
|width="50px"|'''Fig. 1''':
|width="600px" |Representation of the ideal peel curve, i.e., without deformation of the seal seam (dotted curve) compared to the actual peel curve (continuous curve); ''l''d,P – start of the [[Peeling Process|peel process]]; ''l''B – fracture path; ''l''B,i – fracture path in the ideal peel test; ''E''d,P – deformation energy of the peel arms; ''E''d,S – deformation energy of the peeled [[Sealed Seam|seal seam]] and ''E''G,i – ideal total peel energy with permitted deformation of the peel arm
|}

The deformation energy of the peeled [[Sealed Seam|seal seam]] ''E''d,S is thus calculated by subtracting the ideal total peel energy ''E''G,i, i.e. the total peel energy in the presence of an ideal seal seam with infinite [[Elastic Modulus|modulus of elasticity]] (dotted peel curve), from the total peel energy ''E''G according to '''Eq. (2)'''. It is assumed that the peel arm can also absorb [[Deformation|deformations]] in the presence of an ideal [[Sealed Seam|seal seam]].

{|
|-
|width="20px"|
|width="500px" | <math> E_{d,S} = E_G\, -\, E_{G,i}</math>
|(2)
|}

It is assumed that the deformation energy of the peeled seal seam ''E''d,S is not influenced by the deformation energy of the peel arms ''E''d,P, so that the two deformation processes, the deformation of the peel arms and the deformation of the seal seam, occur sequentially. The exact numerical value of the ideal total peel energy ''E''G,i cannot be calculated, but the deformation energy of the peeled seal ''E''d,S can be approximated using '''Eq. (3)'''.

{|
|width="20px"|
|width="500px" | <math> E_{d,S} = E_G - E_{G,i}\approx (l_B-l_{B,i})F_{peel}</math>
|(3)
|}

with
{|
|-
|''l''B
|width="15px" |
| fracture path in the real peel test 
|-
|''l''B,i
|
|fracture path in the ideal peel test, i.e., without deformation of the peeled seal seam
|}

The fracture path in the ideal [[Peel Test|peel test]] is calculated for the [[T-Peel Test|T-peel test]] according to '''Eq. (4)''' and for the fixed-arm peel test according to '''Eq. (5)'''.

{|
|-
|width="20px"|
|width="500px" | <math> l_{B,i} = l_{d,P}\, +\, 2 W</math>
|(4)
|}

mit
{|
|-
|ld,P
|width="15px" |
|start of the [[Peeling Process|peeling process]]
|}

{|
|-
|width="20px" |
|width="500px" | <math> l_{B,i} = l_{d,P}\, +\, (W-W \cos \theta)</math>
|(5)
|}

with
{|
|-
|<math>\theta</math>
|width="15px" |
|[[Peel Angle|peel angle]]
|}

==Application example for a PE-LD/iPB-1 peel system==

The adhesive energy release rate in the low-density polyethylene peel system blended with isotactic polybutene-1 ([[Plastics – Symbols and Abbreviated Terms|abbreviation]]: PE-LD/iPB-1) is significantly influenced by the blend composition. As a result of the [[T-Peel Test|T-peel test]], '''Fig. 2''' shows the adhesive energy release rate as a function of the iPB-1 content. The adhesive energy release rate decreases exponentially with increasing iPB-1 content. This dependence is used as a basis for the targeted adjustment of the PE-LD/iPB-1 peel system using fracture mechanical values (see: [[Fracture Mechanical Testing|fracture mechanical testing]]).

[[File:Adhesive ERR Fig-2.jpg|400px]]
{|
|- valign="top"
|width="50px"|'''Fig. 2''':
|width="600px" |Influence of the mass content of iPB-1 on the adhesive energy release rate
|}

==See also==

* [[Peel Properties of Peel Systems|Peel properties of peel systems]]
* [[Fixed-arm Peel Test|Fixed-arm peel test]]
* [[T-Peel Test|T-peel test]]
* [[Peel Behaviour – Modelling|Peel behaviour – modelling]]

==References==

* Kinloch, A. J., Lau, C. C, [[Williams, James Gordon|Williams, J. G.]]: The Peeling of Flexible Laminates. Intern. J. of Fracture 66 (1994) 45–70 DOI: [https://doi.org/10.1007/BF00012635 https://doi.org/10.1007/BF00012635]
* Nase, M., Langer, B., Müller, C., [[Grellmann,_Wolfgang|Grellmann, W.]]: Bruchmechanische Kennwertermittlung im T-Peeltest und im Fixed-Arm Peeltest. In: Frenz, H., [https://www.researchgate.net/profile/Wolfgang-Grellmann Grellmann, W.] (Eds.): 26. Tagung Werkstoffprüfung „Herausforderung neuer Werkstoffe an die Forschung und Werkstoffprüfung“, Berlin (2008) Proceedings pp. 223–228, ISBN 978-3-00-026399-6 (see [[AMK-Library]] under A 10) [https://www.polymerservice-merseburg.de/fileadmin/inhalte/psm/veroeffentlichungen/Bruchmechanische_Kennwertermittlung_im_T_Peelttest_WP2008.pdf Download als pdf]
* Nase, M., Langer, B., Baumann, H. J., [https://de.wikipedia.org/wiki/Wolfgang_Grellmann Grellmann, W.]: Fracture Mechanics on Polyethylene/Polybutene-1 Peel Films. Polymer Testing 27 (2008) 1017–1025 DOI: [https://doi.org/10.1016/j.polymertesting.2008.09.002 https://doi.org/10.1016/j.polymertesting.2008.09.002]
* Nase, M.: Charakterisierung von polymeren Peelsystemen durch Anwendung neuartiger Methoden der experimentellen Bruchmechanik. Habilitation, Otto-von Guericke-Universität Magdeburg, Shaker Publishing (2022) (ISBN 978-3-8440-8635-5; see [[AMK-Library]] under B 2-3), [https://www.polymerservice-merseburg.de/fileadmin/inhalte/psm/veroeffentlichungen/Nase_Habilitation_Inhaltsverzeichnis.pdf|Content as pdf]

[[Category:Film Testing]]
[[Category:Peel Test]]
[[Category:Guest Contributions]]

Adhesive Energy Release Rate - Revision history