kclo4
National Hazard
Posts: 916
Registered: 11-12-2004
Location:
Member Is Offline
Mood: No Mood
|
|
Keeping polypropylene sheets soft and flexible after autoclaving.
I am autoclaving thin bags/sheets of polypropylene, and after the process it loses some of its flexibility and becomes more ridgid. This is
undesirable, and I'd like to treat the polypropylene with an agent to make it more flexible. I'm not sure that this is possible, but it seems like
some type of wax or oil could possibly alter or inhibit the polypropylene from becoming ridgid and could be added to the plastic or the autoclave.
Any ideas or pointers?
I have tried researching it but I just do not have the language to find such a "softening agent"
Thanks.
|
|
|
Metacelsus
International Hazard
Posts: 2539
Registered: 26-12-2012
Location: Boston, MA
Member Is Offline
Mood: Double, double, toil and trouble
|
|
It would be called a plasticizer. It would probably have to be added to the bags during manufacturing.
|
|
|
CuReUS
National Hazard
Posts: 928
Registered: 9-9-2014
Member Is Offline
Mood: No Mood
|
|
diethylhexyl phthalate is used for softening vinyl gloves,so you could try that.
|
|
|
kclo4
National Hazard
Posts: 916
Registered: 11-12-2004
Location:
Member Is Offline
Mood: No Mood
|
|
Great. I'll look into some of these. What do you think causes polypropylene to become more brittle after the heat? I assume it's that it is
crystalizing or having it's polymer units become less stretched out and kind of fall into themselves?
|
|
|
DJF90
International Hazard
Posts: 2266
Registered: 15-12-2007
Location: At the bench
Member Is Offline
Mood: No Mood
|
|
Is it possible that you might be losing/degrading whatever plasticiser may be present during the autoclaving process?
|
|
|
UC235
National Hazard
Posts: 565
Registered: 28-12-2014
Member Is Offline
Mood: No Mood
|
|
Sounds like autoclaving them is allowing the plastic to release strain built into it during manufacturing or permitting it to recrystallize. Do you
experience shrinkage or just a change in flexibility? I'm not aware of any plasticizers that are compatible with polypropylene (and they would need to
be incorporated during manufacturing). It's properties are usually managed by modifying chain lengths and tacticity instead.
[Edited on 22-11-2016 by UC235]
|
|
|
kclo4
National Hazard
Posts: 916
Registered: 11-12-2004
Location:
Member Is Offline
Mood: No Mood
|
|
Suppose I should elaborate:
They are spawn bags for mushrooms production, from unicornbags.com.
They are very flexible pre-autoclave, but after the fact, folding them sometimes results in pin holes where they are folded. This lets in spores and
ruins the bag. I have to fold them since I sell them online and shipping would be impossible, along with fitting them into the autoclave.
I am not sure that they shrink, if anything they expand.
|
|
|
Cezium
Harmless
Posts: 39
Registered: 5-1-2015
Member Is Offline
Mood: No Mood
|
|
then don't autoclave. try to iradiate it, few tens kGy should be enough.
|
|
|
kingroobythefith
Harmless
Posts: 3
Registered: 26-2-2019
Member Is Offline
|
|
autoclaving polypropyline
while I don't know much about chemistry its possible the heat or pressure caused it to stick together on a small scale or possibly melt its also
possible the structure of the threads in the cloth changes under those condition
|
|
|
Ubya
International Hazard
Posts: 1247
Registered: 23-11-2017
Location: Rome-Italy
Member Is Offline
Mood: I'm a maddo scientisto!!!
|
|
Quote: Originally posted by kingroobythefith  | | while I don't know much about chemistry its possible the heat or pressure caused it to stick together on a small scale or possibly melt its also
possible the structure of the threads in the cloth changes under those condition |
kclo4 never mentioned problems with sticking or melting, and definitely he was not talking about cloth fibers...
you don't know much about chemistry, ok not a problem, but you should be able to read
---------------------------------------------------------------------
feel free to correct my grammar, or any mistakes i make
---------------------------------------------------------------------
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
