Who can help me ?
Using zeolite to remove moisture of polyurethane resins , it will ruin the structure and mechanical strength and resistance of the resin?
Tnaks you
Dear Rezvan, please share with us some details. What is the application? Do you want to absorb liquid water or air humidity? What is the relative humidity? What is the time of exposure? What do you want to prevent by adding zeolite? Plastification or the PUR matrix or hydrolytic damage? Do wet and dry conditions alternate or the humidity level is constant?
The reason I ask these questions is that zeolite behave as reservoir with finite volume, it becomes saturated and on heating it releases Water. The effect on mechanical properties deends on the particle size distribution, volume fraction of the filler and on surface treatment. The best thing is to make model systems and to measure the tensile properties vs. pure matrix.
Thanks for your answer dear gerhard,
Zeolite use to remove the moisture of air , which varies between 6% - 12% (percentage of zeolite on polyol). If I do not add zeolite, just add MDI , make polyurethane foams. zeolite put on dry polyol and then I mix well.
Now I want to know by adding zeolite, changing character mechanical resistence , or elasticity significantly,....
I'll keep in mind that I am using polyol and MDI PPG 1000 (various MDI), to receive a good quality of polyurethane resin, physical resistance and mechanical resistence.
I hope you could explain a little better.
Thanks a lot
Hello.... instead of Zeolite , i think you can set a simple apparatus that circulate nitrogen.
In polyurethane industry usually the component are kept dry and packged so that the moisture uptake is prevented. The opened cans are used within a short time. The addition of zeolite will surely change your properties, you can expect higher modulus and lower elongation at break. The strength change depends on the interfacal adhesion of the matrix and the filler.
Thank you, yes, I see that in fact the property of the resin is changed, but how much and how, I do not know!
Here is the area alps and humidity always there, but this depend a day increases too and one day less.
I think you need to treat two effects separately. First is the effect of water in polyol BEFEORE the reaction with the isocyanate. This reduces the stiochiometry and results in some foaming (CO2). This can be eliminated by thoroughly drying the polyol and the isocyanate components. This can be done by adding zeolite insofar as the adsorptive capacity of the zeolite is enough to bind the water, but there are other methods too. An independent problem is the water absorption AFTER the curing reaction. This will depend on the relative humidity of the ambient air. This cannot be eliminated by adding zeolite. It can be studied by exposing the samples to controlled humidity environments and to measure the water uptake and the changes in the mechanical properties. The effect of zeolite on the mechanical properties can be assessed by comparing the mechanical properties of zeolite filled and unfilled samples.
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