Mechanical Properties for my project

[Mimmim]

Hello,
I've been researching about Mechanical Properties Testing for a while. All of the information I've found is that its use for testing polymer only. I have a substance that I have to run Mechanical Properties Testing, but it recommends that I have to make it as a film by using PLA first. So I wonder why I have to make it as a film before testing? What about if I run testing substance without making it as a film? Can I? Should I?

Thank you so much
Mim

[norman40]

Hi Mimmim,

There’s quite a number of mechanical properties tests and many of those are applied to substances other than polymers. A short listing is provided here:

https://en.wikipedia.org/wiki/Mechanical_Testing

The physical form of a material can affect the some mechanical properties. For example, a single layer of paper might have a low tear strength. A laminate made from several layers of the same paper would have a much higher tear strength. A mechanical test of a polymer film might make sense if you were comparing results with other films.

There are some Science Buddies projects aimed at exploring mechanical properties of materials. You might want to take a look at these as part of your research.

https://www.sciencebuddies.org/science- ... i-strength

https://www.sciencebuddies.org/science- ... s-stronger

https://www.sciencebuddies.org/science- ... ings-break

I hope this helps. Please post again if you have more questions.

A. Norman

[Mimmim]

I have 5 kind of plastic films(each kind have 3 set to make sure that each flim is very similar like thickness or the substance I put into mix well) to compare the properties. It said that I have to run mechanical properties testing 3 pieces for each kind of them. I think it's better if I test 3 set and each set I test 3 pieces (which means I have to test for 9 times each kind of plastic film) ,but I wonder can I test just a piece of film from each set?(which means I have to test 3 times) Is it okay? Or you have any suggestion?

Thank you so much

Moderator note: Hi Mimmim, I moved this post to be part of your original thread, so the expert who has been helping you can see your additional questions.

[norman40]

Hi Mimmim,

Repeated tests of your plastic films will give you an idea of the variability of your test results. You can use this information to help decide if any differences in test results among the types of films are due to random variation or to real differences in the films.

There is no standard number of repeat trials but three repetitions is the minimum. You can assess the results to see if all three trials were similar or if one result was very different from the others. One “stand out” result suggests that something went wrong with that test.

If I understand your post correctly you have three sets of each plastic film. Each set contains three films. My suggestion is to test all nine film pieces. That way you'll be able to assess the consistency of the film sets. And you can combine the results for the sets for comparisons of the different films.

The following links contain some background information on repeat trials and data analysis that you may find useful:

https://en.wikipedia.org/wiki/Replication_(statistics)

https://www.ndsu.edu/faculty/horsley/ExptSize.pdf

https://www.sciencebuddies.org/science- ... e-projects

https://www.sciencebuddies.org/science- ... l-to-noise


I hope this helps. Please post again if you have more questions.

A. Norman