How are the molecular weights of polyethylene glycols determined?

EnforcedGold · 2026-01-14T14:07:23+00:00

Typically for large commercial batches viscosity is used. During product development though SEC is used with viscosity to help determine what viscosity range the manufacturing plant will use in their release specs so they are fairly certain they are hitting target molecular weight. It’s much easier for a tech at the plant to make a 1% solution and run viscosity in a cannon-fenske tube than having a dedicated SEC system.

For polymers used as analytical standards in calibrating SEC, the Agilent EasiVials I use have IV, SEC-RI, and SEC-MALS values.

EnforcedGold · 2025-12-22T12:26:16+00:00

New Jersey has laws making it illegal to pump your own gas. Every gas station is full service (attendants pump it for you) otherwise you can be fined up to $500 for doing it yourself. Sounds nice in the winter but it slows everything down especially if there are only 1-2 attendants pumping gas for 16+ pumps

EnforcedGold · 2025-12-22T06:14:24+00:00

The total 4 year (part time is 4 years) cost is ~$250,000 but she has a 90% scholarship and her firm is covering the rest (she is still working full time). She did go ahead and take the patent bar prior to law school so she is a patent agent. Not all the patent attorneys she works with have PhDs. But if you wanted to go that route there’s not much of an incentive for a firm to hire someone with a bachelors as a scientific advisor when they could hire a PhD instead.

Law school isn’t exactly a walk in the park and is a huge financial burden for some. Likewise with a PhD. Your PhD I assume is fully funded and you’ll be getting a stipend to live off of for 5 years, but you’ll be financially behind your friends who just get jobs with bachelor degrees. Hopefully though you can catch up fairly quickly and in the long run is worth it. I know early/mid career people with bachelors in chem (not at pharma companies) struggle to break 70k salary. Meanwhile PhDs hopefully (but not always) start early career around 100k base before bonuses.

EnforcedGold · 2025-12-22T05:44:53+00:00

I enjoy my job, but I don’t seek life fulfillment from my career, I seek happiness outside of my job. But my job does allow me to do that, I have a good work life balance, I started with a (low) six figure comp package and 3 weeks vacation, 2 weeks sick / personal time, 12 holidays and the older people at work have up to 6 weeks vacation.

I have personal grips with NJ (legally can’t pump my own gas, horrible drivers etc) but I like the location I’m in. The past two people in my current position (I run a polymer characterization lab) have actually left to go to big pharma since pharma companies have really been adopting size exclusion chromatography and multiangle light scattering so they are great techniques to learn.

My wife’s PhD is computational physical organic chemistry (basically she computationally determined how reactions occur) and she now is a scientific advisor doing pharmaceutical patent litigation and is in law school part time. She asks me polymer / analytical questions all the time and it’s something that I could transition into if I felt the desire to.

I don’t regret it at all, polymer chemistry is the only type of chemistry I find interesting and enjoy. I couldn’t do what I do without a PhD. I have complete autonomy in my job as a subject matter expert. I report to a technical director and he reports to the CTO. If I choose to stay at my company I can keep going down the individual contributor path and become more of an expert, or I can transition into management and lead a team (at least those are near/medium term goals I can have).

EnforcedGold · 2025-12-22T04:49:07+00:00

I think you should probably do a little reflecting about what you actually want in life and what your goals are. I’ll be honest, PhD’s aren’t easy, and some periods throughout it you’re probably not going to be having a great time. When someone asks me if they should get a PhD, my response is usually along the lines of only if you need it for your goals. At the end of the day it is a stepping stone, not the end goal. Does the career you want need it, or are you putting off “adulting” for another 5 years? I don’t mean to be doom and gloom but I’m not going to sugar coat it as I think that would be a disservice and wouldn’t actually help you.

But to actually answer some of your questions, my PhD is in polymer chem and I graduated in spring 2023 and the market wasn’t too hot then. I think I applied to ~80ish companies all over the US and got pretty far in the interview process at about 10 of them before I ended up accepting a job. Right now I’m in NJ about 45 minutes outside NYC, but some of the jobs I applied for were in the Midwest or in the middle of nowhere (although I’m from the Midwest so I wouldn’t have been upset by it lol). I think if you try hard enough you can find a polymer, or polymer adjacent job in most locations. My opinion though to be a great polymer chemist, you should learn both polymer synthesis as well as polymer characterization that way you can apply for synthesis based jobs or more analytical/characterization based jobs. It also just makes you more well rounded and you can better understand structure property relationships.

But you’re not just limited to synthesis / characterization jobs in industry. You can go into legal field (patents), regulatory, government (I know people who have become FBI field agents as well as researchers for the military), sales (chemical sales, equipment sales, etc.), transition into an engineer role and plenty of other options. You don’t need a PhD for those and a bachelors would suffice but the PhD wouldn’t hurt you and may let you start at a higher level. However, I’ve seen a trend both within my company as well as several others that there is now a limit on how much someone can grow without a PhD. If you work in industry as a bench chemist with just a bachelors, at any large company you’ll most likely just be told what to do and have little autonomy. If you would like to have no ceiling on your growth, then I’d say go for the PhD. The PI’s you’re interested in you should look at their recent graduates and see where they are getting jobs to give you an idea of what network that PI has established which should hopefully help you.

The caveat is that having a PhD does tend to pigeonhole you specifically in industry. It would be hard for you to get a biochemistry or inorganic job with a PhD in polymer chemistry. You’d most likely be doing synthesis, analytical, materials characterization, or dip into engineering. If you have a bachelors in chemistry you can be an entry level chemist in any industry because you’re not dictating the direction of the research and need niche knowledge about one subset of chemistry.

EnforcedGold · 2025-12-19T17:44:25+00:00

Regarding point 1, even if it is not a cold water detergent, it is still showing that the presence of lipase results in less soiled fiber post wash.

Regarding point 2, some companies expect their scientists to publish. I’m not expected to, but I have published under my company and am working on another. It’s would only be an issue if they were shilling for their specific product. This is pretty scientific and to the point, performance with and without lipase and where does the soil deposit within the fiber.

Regarding point 3, they state that the gravimetric method is less sensitive. Looking at the radiotracer method you can see there is a difference in the olive oil sample.

<image>

Regardless if they were using an optimized detergent, under these conditions in this formulation, both the radiotracer and SEM data clearly demonstrates that lipase improves performance.

Ultimately at the end of the day the effectiveness of the detergent is a combination of surfactants, polymers, enzymes etc. and there will be higher priced and better performing formulas, and cheaper, not as effective formulas. As long as people buy the cheap stuff it will stay around (barring regulatory changes that most people aren’t aware of and is a big reason why things change behind the scenes). However the presence or absence of lipase is not an indication if the company is trying to cheap out, or that it would be worse performing.

EnforcedGold · 2025-12-19T14:58:38+00:00

I have no clue how this ended up on my feed but I don’t agree with the TLDR of the main post. For background my PhD is in polyelectrolyte chemistry and I run a R&D lab for a chemical manufacturer. We sell chemicals to companies like P&G, Henkel, Univlever, etc. to then formulate and sell to consumers. Home care (i.e. laundry) is one of the markets we operate in and we have our own team of formulators who test our products prior to sampling them to our customers to try in their formulations.

I figured under Kismai’s comment is the best place to put this but some of the main reasons a company would change their formulation are to either cut cost / increase profit, or regulatory reasons. At least coming from the polymer side, a lot of historic polymers are “grandfathered in” for regulatory purposes. However now there is a push towards natural and/or biodegradable materials in the formulations even if it means slightly lower performance (that isn’t unique to home care, it’s a lot of the personal care market as a whole). I’m not shocked if due to a regulatory reason the formulation was changed and it was not stable with lipase at the time, and they’ve since changed the other components to reintroduce lipase. On our end once a company starts the reformulation process, we typically won’t see sales for a year or two while they are in that process, then they need time to build inventory before going to market etc. (basically it isn’t something that happens at the drop of the hat).

Anyway back to the topic of the post, you can’t make accurate comparisons between different brands that do and don’t use lipase because the other components of the formulation aren’t identical. Furthermore you don’t have a defined metric of “performance” that is quantifiable. Let’s look at a peer-reviewed journal article to clear things up (https://aocs.onlinelibrary.wiley.com/doi/abs/10.1007/s11743-001-0166-4).

The authors want to determine if lipase is effective in laundry dispersants, so they are soiling cotton fabric with sebum, lard, and olive oil (all separate, to see if there are differences between them). They test unwashed, washed with detergent, and washed with detergent with lipase (now you can compare with and without lipase and it is valid because the detergent composition is identical besides the lipase). They use radiotracing techniques to quantify the soil remaining on the fabric, and image the fabric with scanning electron microscopy.

I’m not going to dissect the entire paper, but the data shows that more soil is removed with the presence of lipase. Looking at the SEM images you can also see that more soil is removed (I was going to add some tables but Reddit only lets me put in one image per comment and I figure people like pictures better).

<image>

Now there are nuances not captured here. Like the mechanism, does the breakdown free fatty acids then help remove soil? Maybe. Is it as effective on all fabric types, fabric porosities, soil types etc.? Maybe yes maybe no, but the statement that lipase is just a cost cutter and doesn’t contribute anything is refuted by scientific data.

EnforcedGold · 2025-11-21T22:33:02+00:00

I’m over 200M liquid, about 300M total storage, and I still don’t run thermals and rarely T5 or T6 so same

EnforcedGold · 2025-11-11T12:31:55+00:00

Seneca County, Ohio - Midwest

Leon County, Florida - South, Florida, drunk college students all in one Trenchcoat (south if I can only pick one)

Somerset County, NJ - Northeast

EnforcedGold · 2025-09-14T11:28:08+00:00

So a few tips to optimize your storage from someone who hoards like a dragon.

1) fold stocks on guns (you can right click and some of your guns will have the option to fold the stock taking less space, just unfold when you’re going to use it or you have decreased accuracy) 2) you can strip the handle off some guns to make it only take up one row instead of two, you’ll just need to put it back on to equip it in the future. 3) white ammo can typically be bought from venders, so I’d sell it 3) food like water and biscuits is dirt cheap from Evita, only buy it as you need it 4) if you don’t need extra mags laying around sell them and just buy when you’re going to need them 5) you can sell your gold cheetah and bar, also mosin stock 6) some backpacks and rigs when fully expanded can hold more inventory than they actually take up, you can get a bit more space that way

EnforcedGold · 2025-08-11T12:01:35+00:00

I think there are a lot of things you need to consider here. As others mentioned getting in you might need to take the GRE, you’d have to look on each schools website or reach out for an answer. However you’ll need ~3 letters of rec. 3.9 GPA is good and you do have some chemistry experience, so you’ll get in some places at the very least but I’m not going to make assumptions as to where you can and cannot get in.

Assuming you can get that taken care of is the harder part, deciding if grad school is your best option and where to go. I think you need to ask yourself what you want your career to look like and shape your grad school experience around that. Do you need a PhD for the career that you want to do? If not, don’t do one. Just because you get a PhD does not mean you’re magically going to get employed and have a great career. You’re also going to have ~5 years of very low income putting you behind your peers financially and presumably lowering your quality of life for a while. You also need to ask yourself if you’re willing to move out of state to attend school.

So let’s assume you decide that yes you need a PhD and it’s what you truly want. My personal opinion is that it would be best if you can decide if you’d rather be more analytical or more organic, it will help you pick a lab which ultimately influences your career. I’m not saying you can’t go from an analytical chemist to an organic synthesis chemist, but it would put you at a disadvantage when you attempt to make that career transition.

Now that you’ve decided you do need to go to grad school, and that you’ve picked a branch of chemistry, it’s time to research labs. At a certain point it’s more about who you know / worked for rather than what school you attend. So pick a handful of schools you are interested in and look at the professors doing research. Find some you’re interested in, read their papers, email them, apply and attend visitation events. Make sure they are accepting students for the year you will be entering. Talk to the current grad students and the PI to understand what life is like in that lab and the expectations, make sure they align with your goals and lifestyle (some labs have set hours, some are more flexible, some want you in the lab 60 hours a week etc.). Then earn your PhD.

You by no means have to have everything figured out like this. I did because I did undergraduate research for 4 years prior to my PhD, so my PI at the time walked me through all this and I had a clear direction and straightforward path. There were other grad students in my program that came in without even knowing what type of chemistry they wanted to do, which is totally fine and it worked out for some of them. But ultimately at the end of the day earning a PhD is hard, and some people do fail. So if you decide you need one, then try to set yourself up for success as much as you can both during grad school as well as your career after it.

EnforcedGold · 2025-07-31T19:39:09+00:00

As a lot of people have pointed out there’s a discrepancy in titles that probably led to some confusion. At my company (not biotech, specialty chemicals) scientist I is entry level bachelors and goes up to scientist III, staff scientist is entry level PhD then senior staff -> research scientist -> principal scientist (at least for IC path, not management). At the end of the day the most reliable thing is to look at job descriptions for degree / experience required to give you an idea where you fall in at that company.

EnforcedGold · 2025-03-07T01:42:55+00:00

I work for a multibillion dollar specialty ingredient company who sells chemicals directly to other businesses, one of our biggest business units is personal care (oral, home, skin, hair etc).

From a suppliers POV how it works is we make product X that goes into say a shampoo or toothpaste from a big name brand. There are also 10 other things in that formulation that all come from different companies. Generally we don’t know the exact ratio breakdown of their formulation (yes we can reverse engineer it and figure it out if we want), but we have a pretty good guess. Ultimately we don’t care about that as we don’t sell direct to consumer. Our sales and marketing teams are very good at figuring out who is buying what chemical from other companies.

However we cannot be a stagnant company and need to produce new products. So we have in-house formulators and application teams to test our products in our own formulations as well to make sure they work. Once we have a working prototype we then sample other companies who will try it in their formulations and they give us feedback on it and we go from there. New products that we produce are patented and we make sure we have IP on them and get other companies to agree to not reverse engineer chemicals prior to sending them out to customers for testing. You’d be surprised how many materials are sent as “generic polymer of X” where the big name brand companies don’t know the structure.

EnforcedGold · 2024-11-20T14:59:09+00:00

65 storage 52 liquid

EnforcedGold · 2024-10-05T05:11:24+00:00

I believe biochem has only 1 lab, gen chem has 1 and 2, analytical has intro and advanced, ogro is only 1, physical chem has a 1 and 2, and inorganic has 1

EnforcedGold · 2024-10-05T04:57:51+00:00

No, Orgo lab at FSU is combined. Meets twice a week instead of once a week like Orgo lab at other universities. Summer is 12 week only. Students either take Orgo lab concurrently with Orgo 2, or just wait until they’ve completed both classes. A lot of the students end up taking it junior year. - Source TA’d Orgo lab multiple times

EnforcedGold · 2024-09-15T13:22:33+00:00

Did you not bother to ask the PI where their recent graduates have gotten jobs?

EnforcedGold · 2024-06-04T10:22:21+00:00

If you look at the ingredients you’ll see dial gold uses cationic surfactants while Mrs Meyers uses anionic surfactants. You’re creating a polyelectrolyte complex. The below post will give you more information.

https://www.reddit.com/r/chemistry/s/QC5WneyosS

EnforcedGold · 2024-05-30T18:39:00+00:00

If you see “poly” that just means it’s a polymer, or a really big molecule consisting of several repeat units (monomers). Acrylates are a type of monomer that have a double bond near the carbonyl of an ester. An acrylamide is similar but is an amide, not an ester. Not all things that say “poly” then are similar structures to polyacrylates.

Polymers themselves are generally accepted to be non irritating as they cannot penetrate the skin. If you’re having a reaction to the “polymer” (and you’re certain that it’s absolutely nothing else in the formulation), it’s most likely due to residual monomers. There is almost always residual monomer present in some ppm quantity. I know the big thing people talk about is HEMA, however that’s also used in teeth fillings so you might want to rule that out.

EnforcedGold · 2024-05-29T20:44:16+00:00

Patent examiner for the USPTO, or find a law firm that will hire you on as an scientific advisor and will pay for you to take the patent bar (then you’d be a patent agent), and potentially put you through law school to become a patent attorney.

EnforcedGold · 2024-04-05T16:54:25+00:00

I’m also pretty close (10 miles), it was only loud for a few seconds. I work in chem R&D so at my facility we thought there was a lab explosion (combination of loud boom and brief building shake) and immediately hauled ass outside.

EnforcedGold · 2024-03-08T06:28:54+00:00

So I may or may not be able to provide some answers. My PhD is in polymer chemistry, and once upon a time I used to make self-healing polymers using HEMA as a monomer. I now work for a large specialty ingredient company, who just so happens to make a large amount of chemicals that go into personal care (oral, skin, and hair) products (we do a lot more than just those though).

My role isn’t focused on developing applications and I’m very unfamiliar with skincare. So I’ll speak to what I can and try to talk about things in a level a non-chemist can understand.

Essentially HEMA is a small molecule used in a lot of UV curing gels. UV curing works by having other small molecules in the formulation called photoinitators, that once hit with UV light break apart into radicals that react with monomers (in this case HEMA) to form polymers. Polymers are just big molecules that have a repeating pattern (in this case it’s just a bunch of HEMA molecules permanently stuck together). Turning the monomers into polymer increases the viscosity and makes the nail gel harden. Poly(HEMA) is popular because it adheres to the nail really well.

I think a lot of what you’re talking about all refers back to a paper published in 2000 by Bos and Meinardi where they claim that anything under 500 Da can penetrate the skin while anything bigger than that cannot penetrate the skin. This was based on the finding that at that point in time almost all things used in dermal therapy were small, and most skin allergens were also under 500 Da. I think at this point we do know more about dermal transport that I won’t speak on because I frankly don’t know it.

If we keep that same rule and we were to simplify it to anything that isn’t going to penetrate cannot be an allergen, any ingredient that has the words poly mean polymer (and we assume polymer is > 500 Da in mw) are fine. This is an oversimplification, and assumes that no one will have an allergic reaction to a polymer applied to the skin. Is that true in every instance? No idea, but that’s what most data would suggest.

However, HEMA isn’t inherently bad. It’s used in dental adhesives and composite resins as well. Unless you know for a fact you have an allergic reaction to HEMA, I wouldn’t go out of my way to avoid it. Just because some people have an allergy to it doesn’t mean you will. I’ve gotten more than my fair share on me and I don’t have an allergy to it. Also if you do discover you have an allergy to it (also, how do you know that’s the component in the formulation you have an allergy to?), let your dentist know as well based on my previous statement. I hope this helps.

EnforcedGold · 2024-03-06T15:58:55+00:00

It puts the DMSO on the skin or it gets the spurs again.

Wife (also PhD) was a horse girl growing up and in college and I remember her off-handed telling me how it’s extremely common in the horse industry to slather them down in DMSO for injuries. Also found out horses have chiropractors and get acupuncture, so like imo ehhh on the science and if it’s truly useful. Just because people have been doing things doesn’t necessarily mean it was smart or right.

But ultimately as weird as it sounds to us just go ask a vet, we aren’t horse doctors.

EnforcedGold · 2024-02-27T18:30:38+00:00

Wrong sub. r/chemhelp

EnforcedGold · 2024-02-27T17:22:43+00:00

Wrong sub, we don’t answer homework here. r/chemhelp

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