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Can Dimethicone 350 be heated?
I’m finally getting the opportunity to use dimethicone after being restricted by certain people from including it in my formulas. I am going to go with 350 as that seems to be a pretty standard type for my purposes (body butter).
I don’t have any experience with dimethicone, can it be heated with the oil phase up to 85 or should it be added during cool down?
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16 Replies
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Have at it. Not volatile.
As this grasshopper was taught….your silicones are the most difficult ingredient to emulsify (with typical emulsifiers you are using), so you want them in the process…..as early as possible. (Oil phase of course.)
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Thank you! A “chemist blog” I sub to has D350 in the cool down phase. It seemed weird to me - you may have saved my batch (though I likely lost some panthenol and Allantoin). I’m kind of irritated - second time in a week I’ve received inaccurate info from her. Abundant gratitude!
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Got it, i can’t wait.
Are there any tricks for getting it to emulsify other than putting it in the heated oil phase and if needed, adding more emulsifier?
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GeorgeBenson said:Got it, i can’t wait.
Are there any tricks for getting it to emulsify other than putting it in the heated oil phase and if needed, adding more emulsifier?
Not aware of any tricks. Some emulsifiers do a better job with silicone than others…but assuming the use rate you will use….probably not going to be an issue.
In my deo….where I am in that 8-10% range of ‘cones’, I have to pay a little more attention (mainly D5).
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When you say D5 what are you referring to exactly? I’ve heard you mention it before but I see many different results when i search it on the ol’ prospector…
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GeorgeBenson said:When you say D5 what are you referring to exactly? I’ve heard you mention it before but I see many different results when i search it on the ol’ prospector…
Cyclomethicone / cyclopentasiloxane. D5 is just quicker to write/type.
(D5), contains five repeating units of silicon (Si) and oxygen (O) atoms in a closed (cyclic) loop.
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Yes, you can heat it. You can also heat lower viscosity dimethicone (down to 5)
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Dimethicone comes in various sizes, based on how many Si-O units it has.
D5 is as Graillotion described. D350 has 350 repeating units and is therefore much bigger. It does not evaporate quickly (if at all) when heated to normal process temperatures.
More Si-O units means bigger molecules, which trends with greater viscosity, higher boiling points and thicker aesthetics.
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great, i appreciate the info.
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RobboAU said:Dimethicone comes in various sizes, based on how many Si-O units it has.
D5 is as Graillotion described. D350 has 350 repeating units and is therefore much bigger. It does not evaporate quickly (if at all) when heated to normal process temperatures.
More Si-O units means bigger molecules, which trends with greater viscosity, higher boiling points and thicker aesthetics.
The 350 in Dimethicone 350 is referred to its (kinematic) viscosity -which is 350 cSt- and not to the number of repeating units. If you asume 350 repeating units, then your dimethicone 350 would have a molecular weight close to 27k g/mol, which is way higher than the value you can find from different suppliers, which is no higher than 300 g/mol.
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350 cSt dimethicone has a molecular weight in the range of 13’000-15’000 g/mol depending on the manufacturer (some sources say half that number). What I found is, that 27 kDa corresponds to 1000 cSt dimethicone… it’s a mess…300 g/mol is slightly above the molecular weight of the tetramer which has a viscosity of ~1.5 cSt.Viscosity of polymers usually varies greatyl because they aren’t pure but blends of different chain lengths. Dimeticones are sometimes also branched and not exclusively linear, contain additional siloxane moieties, or may be endcapped etc. which all affects viscosity.Bottom line is, dimethicone 350 contains approximately 200 monomers and dimethicone chain length doesn’t have a linear correlation with viscosity. If memory serves me right, dimeticones above ~6 cSt aren’t volatile and can be added to the hot phase without any losses. -
Pharma said:350 cSt dimethicone has a molecular weight in the range of 13’000-15’000 g/mol depending on the manufacturer (some sources say half that number). What I found is, that 27 kDa corresponds to 1000 cSt dimethicone… it’s a mess…300 g/mol is slightly above the molecular weight of the tetramer which has a viscosity of ~1.5 cSt.Viscosity of polymers usually varies greatyl because they aren’t pure but blends of different chain lengths. Dimeticones are sometimes also branched and not exclusively linear, contain additional siloxane moieties, or may be endcapped etc. which all affects viscosity.Bottom line is, dimethicone 350 contains approximately 200 monomers and dimethicone chain length doesn’t have a linear correlation with viscosity. If memory serves me right, dimeticones above ~6 cSt aren’t volatile and can be added to the hot phase without any losses.
Yes…. 5 and 6…is the dividing line.
(Hence why they sell both….with such similar cSt.) -
Good lordketchito said:
RobboAU said:Dimethicone comes in various sizes, based on how many Si-O units it has.D5 is as Graillotion described. D350 has 350 repeating units and is therefore much bigger. It does not evaporate quickly (if at all) when heated to normal process temperatures.
More Si-O units means bigger molecules, which trends with greater viscosity, higher boiling points and thicker aesthetics.
The 350 in Dimethicone 350 is referred to its (kinematic) viscosity -which is 350 cSt- and not to the number of repeating units. If you asume 350 repeating units, then your dimethicone 350 would have a molecular weight close to 27k g/mol, which is way higher than the value you can find from different suppliers, which is no higher than 300 g/mol.
Wow, I’m just about to start a formulation with 350 too!
I wonder if my fragrance supplier can tailor a hot baked humble pie fragrance for me
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@RobboAU I don’t think I made a disrespectful reply to your comment, and I didn’t know one can’t make a mistake without being mocked, but well, you always meet different types of people.
My comment was correct, except for the molecular weight of the Dimethicone 350 (wrong source of information, my bet). And as @Pharma mentioned, there’s no linear correlation between a polymer’s viscosity and its molecular weight -# of repeating units, if we were to talk ideally about linear molecules- (there’s a relationship, of course, but not linear).
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ketchito said:@RobboAU I don’t think I made a disrespectful reply to your comment, and I didn’t know one can’t make a mistake without being mocked, but well, you always meet different types of people.
My comment was correct, except for the molecular weight of the Dimethicone 350 (wrong source of information, my bet). And as @Pharma mentioned, there’s no linear correlation between a polymer’s viscosity and its molecular weight -# of repeating units, if we were to talk ideally about linear molecules- (there’s a relationship, of course, but not linear).
You weren’t disrespectful at all, I had completely misunderstood the 350 due to assuming it had the same meaning as the numbers in D4-6 cyclomethicones.
The formulation I’m working on wanted a thicker aesthetic and a silicone after-feel, for which I was turning to 350 on mistaken logic. I’d rather find out now than weeks later!
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@RobboAU Then I misunderstood your comments, my apologies. Anyway, I’m glad it was all helpful at the end
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