The Ni(II) complexes [Ni(5-C5H3 R2)(X)(NHC)] 1a–f combined with MAO was tested in methylmethacrylate (MMA) polymerization. The complex 1f, bearing the bulky 2,6-diisopropenylphenyl substi.
Journal of the American Chemical SocietyDOI: 10.1021/jacs.0c13397
Sebastian M. Fica-Contreras, David J. Hoffman, Junkun Pan, Chungwen Liang, and Michael D. Fayer
https://ift.tt/3bA2O1G
Journal of the American Chemical SocietyDOI: 10.1021/jacs.0c11204
Tomoyuki Ikai, Satoshi Kawabata, Fumihiko Mamiya, Daisuke Taura, Naoki Ousaka, and Eiji Yashima
https://ift.tt/384S2yD
I have a question about removing mono methylether hydroquinone from methyl methacrylate. I always percolate the methy methacrylate through a short activated alumina column to remove the inhibitor, but my boss is not sure about it effectiveness, somebody knows the appropriate amount of alumina for each milliliter of methyl methacrylate to remove properly the inhibitor? Thank you.
Hi guys!
I work for a research histology laboratory and recently we've been having some serious trouble with our MMA. I have very little experience in plastics but have been tasked with troubleshooting this so I'm doing quite a bit of research and collaborating with peers. Our procedures have reportedly worked great in the past and have not changed for ages but a few variables have. Just curious if anyone else has experience or advice.
We are currently using MMA (stabilized with MEHQ), and dibutyl phthalate, with Perkadox 16 as a catalyst. In lieu of not destabilizing the MMA, we use more catalyst. Our samples are ~20cm³ on average, although some are considerably larger.
The problem: 1. Samples will not polymerize. 2. Samples take MONTHS to polymerize. 3. Samples form bubbles within the plastic therefore obstructing view of the tissue, requiring additional radiographs. Note: I have been told infiltration of the tissue itself is fine, stains well.
Procedure: 1. Dehydrate in ethanol, clear in xylene on processor (vacuum ON, room temperature). 2. Infiltrate in MMA (no vacuum, room temperature). 3. Infiltrate in MMA + catalyst (no vacuum, room temperature). 4. Embed in glass jars (no vacuum, 4 degrees C). 5. Cross your fingers and hope it polymerizes.
Possible variables: 1. Methyl methacrylate monomer was, reportedly, previously stored at room temperature. It is now stored at 4 degrees C and used cold, straight from the refrigerator. 2. Suppliers of reagents have changed over the years . 3. In the past, all solutions were reportedly degassed. 4. No desiccant currently used at any step.
Current hypotheses: 1. Polymerization slows or does not happen due to presence of oxygen in tissue/solution - needs degassed, 2. water contamination by condensation from storage in refrigerator and no desiccant used when allowing to polymerize in refrigerator.
Additional points of discussion: 1. What is the difference between hydroquinone and monomethyl ether hydroquinone (MEHQ) when used in MMA as a stabilizer? Current supplier's certificate of analysis tested at 15 ppm MEHQ. A possible lead specified using MMA stabilized with hydroquinone at 25 ppm. 2. Method development with benzoyl peroxide is also in the works but as of current, nothing has polymerized. 3. In need of ideas to label specimens within the plastic that won't bleed or melt.
I'm sorry for the poor formatting and the length but if anyone has anything to add, I'd greatly appreciate it.
Hello,
I am thinking of making a fish tank from MMA and I cannot seem to find whether or not it is safe for both fish, and myself. Namely, I cannot find much data on whether MMA "leeches" into water, or if it safe for potable water.
Can anyone point me answer this, or point me to a resource where I can find the answer? Googling, and the FDA website has left me a little hazy.
Many, many thanks!
Anyone have any suggestions? I'm looking for a basic introduction to the polymerization reactions applicable to all three - and some examples of industry uses and developmental history of the three as well. I could also use a general introduction to polymer chemistry, but with more detail than what would be found in an undergrad organic chemistry text book.
Thanks!
Hi guys!
I work for a research histology laboratory and recently we've been having some serious trouble with our MMA. I have very little experience in plastics but have been tasked with troubleshooting this so I'm doing quite a bit of research and collaborating with peers. Our procedures have reportedly worked great in the past and have not changed for ages but a few variables have. Just curious if anyone else has experience or advice.
We are currently using MMA (stabilized with MEHQ), and dibutyl phthalate, with Perkadox 16 as a catalyst. In lieu of not destabilizing the MMA, we use more catalyst. Our samples are ~20cm³ on average, although some are considerably larger.
The problem: 1. Samples will not polymerize. 2. Samples take MONTHS to polymerize. 3. Samples form bubbles within the plastic therefore obstructing view of the tissue, requiring additional radiographs. Note: I have been told infiltration of the tissue itself is fine, stains well.
Procedure: 1. Dehydrate in ethanol, clear in xylene on processor (vacuum ON, room temperature). 2. Infiltrate in MMA (no vacuum, room temperature). 3. Infiltrate in MMA + catalyst (no vacuum, room temperature). 4. Embed in glass jars (no vacuum, 4 degrees C). 5. Cross your fingers and hope it polymerizes.
Possible variables: 1. Methyl methacrylate monomer was, reportedly, previously stored at room temperature. It is now stored at 4 degrees C and used cold, straight from the refrigerator. 2. Suppliers of reagents have changed over the years . 3. In the past, all solutions were reportedly degassed. 4. No desiccant currently used at any step.
Current hypotheses: 1. Polymerization slows or does not happen due to presence of oxygen in tissue/solution - needs degassed, 2. water contamination by condensation from storage in refrigerator and no desiccant used when allowing to polymerize in refrigerator.
Additional points of discussion: 1. What is the difference between hydroquinone and monomethyl ether hydroquinone (MEHQ) when used in MMA as a stabilizer? Current supplier's certificate of analysis tested at 15 ppm MEHQ. A possible lead specified using MMA stabilized with hydroquinone at 25 ppm. 2. Method development with benzoyl peroxide is also in the works but as of current, nothing has polymerized. 3. In need of ideas to label specimens within the plastic that won't bleed or melt.
I'm sorry for the poor formatting and the length but if anyone has anything to add, I'd greatly appreciate it.
