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Surface Modification of LDPE Layers Using Low Temperature Plasma For Enabling Adhesion Measurements

Jonsson Larsson, Fredrik LU (2015) KTE720 20151
Centre for Analysis and Synthesis
Popular Abstract
For the juice package to protect and keep your juice fresh it is important that the different layers in the packaging material sticks very well together. The ability for two things to stick together is called adhesion. For the people that create juice packages, this is important to measure so that the packages don’t leak. This measurement has turned out to be very tricky, but this study has shown that there might be a new method making the measurement of the adhesion possible, with the help of using plasma and ordinary super glue.

How come that the juice in the package doesn’t wet and destroys the carton material and leaks out on the table? For this not to happen, the carton is covered by a really thin plastic layer, keeping the juice... (More)
For the juice package to protect and keep your juice fresh it is important that the different layers in the packaging material sticks very well together. The ability for two things to stick together is called adhesion. For the people that create juice packages, this is important to measure so that the packages don’t leak. This measurement has turned out to be very tricky, but this study has shown that there might be a new method making the measurement of the adhesion possible, with the help of using plasma and ordinary super glue.

How come that the juice in the package doesn’t wet and destroys the carton material and leaks out on the table? For this not to happen, the carton is covered by a really thin plastic layer, keeping the juice away from the carton. Sometimes there is a need for packages to have an extra layer between the carton and the inside plastic layer. This layer is made out of aluminum, and it is used to make sure that no sun light or air gets through the package material and makes the juice go bad.

What all these carton packages has in common is that they should protect and keep the food that they contain fresh. For this to be possible, it is important that the different layers in the packaging material sticks together. The phenomenon how well two material sticks together is called adhesion. When you are using tape to stick a piece of paper to the wall, it is the adhesion between the glue on the tape and the wall that does this. Adhesion could be created in many different ways. It could be created when two materials come in close contact and the surfaces hook onto each other, but it could also be that the molecules on the surfaces attracts each other, similar to the way to magnet acts when they are close to each other.

For companies producing packages and packaging material it is important to be able to measure the adhesion between the used material layers. This is to make sure that they don’t come off when they are filled with milk or juice, transported to the supermarket, and then finally used by you. To be able to measure this adhesion between the layers the material could be put into a machine that pulls the two layers apart. This has turned out be a real challenge because the plastic layer in the material won’t stick to any glue used.
The aim of this project was get a metal stud to stick to the plastic layer with the help of an ordinary super glue. The material would then be put into a machine that would pull the two layers apart. For this to be possible, the adhesion between the plastic layer and the glue had to be improved.

To increase the ability for the glue to stick to the plastic surface, the plastic material was treated with a very reactive gas, called plasma. This treatment was performed inside of a microwave oven where the gas was generated. This method helped to change the molecules on the surface of the plastic layer, making it attracting the glue in a similar way two magnets attracts each other.
In an experiment where different layers were pulled apart, it was shown that the plasma-treated and glued samples were able to hold on to each other five times stronger than before.
When the plasma-treated samples were further analyzed it turned out to be the lack of adhesion between the aluminum and the glue now limiting this new way of measuring adhesion.

It also turned out that the super glue used unfortunately wandered through the thin plastic layer and affected the adhesion between the aluminum foil and the plastic layer, making the new pull test not useful. That is why a new glue must be found that does not wander through the plastic. In the future it would be interesting to look at the possibilities to increase the adhesion between aluminum foil and the glue, suggestible with a similar plasma treatment. (Less)
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author
Jonsson Larsson, Fredrik LU
supervisor
organization
course
KTE720 20151
year
type
H2 - Master's Degree (Two Years)
subject
keywords
polymerteknologi, polymer technology
language
English
id
8168689
date added to LUP
2015-11-18 15:23:49
date last changed
2015-11-18 15:23:49
@misc{8168689,
  author       = {Jonsson Larsson, Fredrik},
  keyword      = {polymerteknologi,polymer technology},
  language     = {eng},
  note         = {Student Paper},
  title        = {Surface Modification of LDPE Layers Using Low Temperature Plasma For Enabling Adhesion Measurements},
  year         = {2015},
}