Wet Tensile Strength

[angie07]

Hello:

 

I am trying to determine the wet tensile strength for tissue fibers in units of pounds per ton. All I know is that a wet-strength resin is added to the tissue fibers and is present in an amount of at least 0.1 dry weight percent.

 

Is there enough information to do this conversion? Or what other information would be required?

 

Thanks in advance.

[studiot]

Hello:

 

I am trying to determine the wet tensile strength for tissue fibers in units of pounds per ton. All I know is that a wet-strength resin is added to the tissue fibers and is present in an amount of at least 0.1 dry weight percent.

 

Is there enough information to do this conversion? Or what other information would be required?

 

Thanks in advance.

 

Well yes quite a lot more is required to even formulate your question properly.

 

Firstly the strength of the tissue and the strength of the fibres themselves are different things. Which do you want?

Edited January 14, 2015 by studiot

[DrP]

Do you have a tensiometer or are you planning to due some sort of crude snap back tests?

 

I'd vary the resin loading from 0 to 0.2% in 0.01% increments and plot tensile strength vs resin loading. The graph should give you some good information. What is it you are trying to find out exactly?

[angie07]

Thanks for your replies.

 

I am trying to find out the wet strength of cellulose tissue based on the limited information provided, if possible.

 

I am not a scientist and do not plan on doing any testing. However, it is important for a work-related assignment to know if such a calculation is possible based only on knowing the dry weight percent of wetting agent resin. My opponent has argued that simply doing the calculation (0.001*2000) will reveal wet strength of the tissue and I am doubtful.

 

 

 

 

[studiot]

Well your colleague is having a joke at your expense.

 

"pounds per ton" is not a measure of strength.

 

Strength could be measured (calculated) in pounds weight or tons weight under for a standard size and shape of sample.

 

You might like to think about the strength of rope or fishing line which can be specified in pounds, meaning the force required to break that rope or line.

Edited January 14, 2015 by studiot

[DrP]

Yea - How long is a piece of string? I think you'd need to do some actual measurements of the tensile strength of the tissue with a tensiometer. Simply trying to work out the strength of the tissue based on knowing that it is a cellulose fibre is not practical.... for example... how thick is the tissue? Tissue thickness will be in direct correlation to tensile strength. There will also be other factors effecting this such as how wet? Completely saturated or just dampened? See? If you have some base starting values that you actually know, then you will be able to work out/extrapolate for other situations and polymer loading... but you need something to start with, like actual tensile values of the paper with and without resin would be a start.

 

Good luck - let us know how you get on.

I wanted to try testing the tensile strength of an adhesive we make a few years back - the QC has always just been a simple 'stick together then try to break it' test. I thought I could do some formulation tweaks to improve the adhesive strength (and make the product cheaper if poss) if I could get actual values for the strength of the joints made with slightly differing formulations. I did not want to buy a brand new modern tensiometer.... I got a very old second hand one for a couple of hundred quid. It was for paper really, but I thought I could stick lolly pop sticks together with a measured amount of glue and break the joint in the machine to get a reading... it was a good idea, but the machine was SO old (antique really lol) it had a spring back mechanism and a dial to read off the values... as it was my glue was too tough to break in the machine (The sticks tore before the glue) so it did not work, but only cost me peanuts compared to the thousands it would have cost for a new machine..... Long story short... my mates were quite impressed and a little envious that I was 'testing the strength of joints' all week at work. ;-)

[studiot]

 

DrP

I wanted to try testing the tensile strength of an adhesive we make a few years back

 

In general it is the shear strength, not the tensile strength that is important with adhesives.

[DrP]

Thanks - yea, sorry I think you are right stud.... it was probably that which I was measuring (or trying to) as the lolly pop sticks were glued together and then pulled apart so that they would slip over each other... it did not matter too much as I just wanted something reproducible that would allow me to compare different but similar samples. I think the machine was originally used for paper strength tests, so was no where near spec for my joint strength tests. If it wasn't such an antique (and if I actually owned it - lol) I would offer to send it to the OP to do some tests with - it should be much better for tissue then sticks... closer to what it was spec'd for. Alas, it is so old I am not sure it would be of use to anyone who wasn't the most patient of folks... I recon you'd have to do dozens of tests and ignore half of them and average out the rest due to the inconsistency of the machine.