Hygroscopic materials and drying

An introduction to hygroscopic materials

[@yteg0210]

Thank you for your teachings. I truly believe in every variable towards discovery. I hope the world enjoys these discoveries as much as I enjoyed writing them.

[@theboz1419]

At work we have started to use PHA plastic. Lots of issues with its hygroscopability. Our dryer hopper is set at 60c and it takes about 3 hours for non dried material to reach our process. Along with a PHA colorant at 1.5% that is not dried. That non dried material. I believe is causing most of our issues. This is also in out facility where our process water is at 70c, causing very high humidity around the 10 machines. Let's just say PHA extrusion has been hell for us and our customers. My biggest issue is making the owners of the company believe water is the cause of most of the problems.

[@vadakkesubramanyam1243]

Sir, can you please let me know how to keep hygroscopic materials dry even if exposed to air. Particularly Tri sodium phosphate.

[@josephelmurr1402]

Thank you for the excellent content. I was wondering if you can advise on hygroscopic material that expands when wet and shrinks when dry without losing its structural properties? Also, how do you quantify the response rate i.e. how quickly the hygroscopic material retains water? Which material reacts the fastest?

[@PLE_LU]

Sorry, I don't think anyone at our department can answer that. We have people working with things like catalysts, carbon capture, pretreatment and fermentation of biomass, waste water treatment, city planning in connection with design of waste water and flood water infrastructure, membrane processes, purification of biopharmaceuticals using chromatographic systems, optimisation and controlling e.g. chromatographic systems, various analysis using syncothron facilities (e.g. Max IV) and similar. We used to have a full time professor who specialised in drying processes, but he has retired and only works part time with us nowadays.

[@yteg0210]

🪵 wood expands and shrinks into more density without losing it's structural properties, but gains more integrity. To quantify these reactions, time lapsed frame rates are taken place. A sponge 🧽 should react the fastest.

[@mchap6118]

Is this for real? Watering your pianos? I've never heard of this in my life.

[@PLE_LU]

Yes, definitely, and they have been around for quite a number of years, but I don't know how common they are in different parts of the world. (Different climates, different needs. With temperatures below 0°C outside, indoor air tends to become really dry and that is not good for wooden instruments) Next time you visit a church, concert hall or similar check if you see a small tell-tale LED and the plastic tube used for watering. In the system I have and the systems I have seen in churches in Lund, a red light means it is on, a blinking yellow light that it is time to water and a steady yellow light that you should have watered it a long time ago) Once you know where to look they are pretty visible. A piano or a grand piano with a climate control system (or, for that matter, placed in a room with climate control) hold their tuning for longer. A similar thing, but much much simpler in design (and I don't know how well they worked) were the tubelike things (1980s?) you could hang into a cello to try to keep the moisture level more constant. I haven't seen them in a long while, which may be because they didn't work as intended (but I'm only guessing now, I'm not a cello player)

[@evazhang3232]

Good day, Professor: I have some questions concerning the property of hygroscopics. I found some contradictions between hygroscopic and less or nonhygroscopicity for the same substance. later on, I realized they are in a different form. one is in crystalline form but another is in powder form. Please forgive me for the potentially confusing terms. for the same substance, for example, D-mannitol. when does it have the property of hygroscopicity and when does it have the property of nonhygroscopicity? Thank you!!!

[@PLE_LU]

This video is about the very basics of hygroscopic materials and simplifies in that it divides materials into two distinct categories: hygroscopic materials and non-hygroscopic materials. In reality, the line between the two categories is blurred. As usual, reality is more complex than our models of reality

[@evazhang3232]

@@PLE_LU Thank you so much for the reply. Do you have any recommendation websites or public resources that can find info on the properties of hygroscopic of certain substances? like chemical property info in general. I have found sits that list detail info for melting point boling point, but not its hygroscopic info. does hygroscopic is a general property of a substance? or its a phenonmenon will change according to varies condition?

[@PLE_LU]

Sorry, I have no good further reading hints apart from that there is information sprinkled in various standard chemical engineering text books. Just to mention one thing, if you have substances that different form of crystals with varying amount of crystal water, you can get behaviour that definitely isn't covered in this video. You can also compare with pF curves for soil, i.e. how much negative pressure you need to apply to suck water out of soil at varying moisture levels. Soil also typically has a moisture threshold under which the structure changes turning it hydrofobic (which you might experience if you forget to water your indoor plants for too long.

[@evazhang3232]

@@PLE_LU THANK YOU!!!

[@SadicTaylor-rx3kt]

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