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Reply
| | | From: Manu (Original Message) | Sent: 6/18/2004 12:27 PM |
Hello All, I just joined this group. I am a high school student and I am supposed to complete an assignment on Thermo and Thermosetting plastics. I have been all over the Net searching for some information. I am specifically looking for the chemical properties of these categories of plastics and how they are manufactured. I will be needing some guidance as to the chemical equations representing the manufacturing processes involved. Could you please guide me through this. I have only a few days left until my deadline. Thanks. |
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Reply
| | From:  jimfee | Sent: 6/18/2004 12:31 PM |
Manu,
Steve is great! He helped me out w/a bio question. He will help u when he
receives ur message. Hang in there!!!
Jimfee
>From: "Manu" <[email protected]>
>Reply-To: "Chemistry Corner" <[email protected]>
>To: "Chemistry Corner" <[email protected]>
>Subject: Thermo and Thermosetting Plastics
>Date: Fri, 18 Jun 2004 04:27:43 -0700
>
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Reply
| | | From: ·Steve· | Sent: 6/19/2004 12:48 AM |
Hey, thanks Jimfee, I'll do my best! 
Hi Manu, and welome to CC! At least for your topic, there are plenty of Internet sites to explore. Here are a few that looked useful to me - this was a quick keyword search and I didn't have time to examine very many of them carefully.
The U. Michigan site is good if you need reaction examples that you can cut and paste into your report. Also, Richard Pendarvis has a popular organic links page, with links to polymer sites at http://fn1.tfn.net/~pendarr/polymers.html that also have graphics of polymer-forming reactions.
Hope this helps!
Steve
Quick review of terms -
Thermoplastics are the type of polymers we usually mean when we say "plastic". They become soft and viscous when heated and thus can be molded into all sorts of common items - toys, plastic bags, soft drink bottles, beads, telephone sets, etc. The polymer chains have little or no crosslinking. This allows the polymer chains to be able to slip past each other when the plastic is melted. The shape is retained when the polymer is cooled.
In contrast, thermoset plastics or thermosetting resins consist of highly crosslinked polymer chains. Because of this crosslinking, very hard, insoluble solids result that cannot be remelted once the crosslinks are in place. They can be molded when they are first prepared, but once they are cooled, they harden irreversibly and cannot be remelted. The first thermoset resin was Bakelite, back in 1907. It is made by the reaction of phenol and formaldehyde. When this mixture is heated, water is eliminated and many cross-links form, resulting in a rock-like mass. (See http://tooldoc.wncc.nevada.edu/bakelite.htm for a graphic of the reaction.) Epoxy resins or epoxy glues consist of two components that must be mixed just before use. One component is a liquid "prepolymer" which is actually a polymer without any crosslinks yet. The second component is a "curing agent" that reacts with the prepolymer causing cross-linking to occur. The monomers that the prepolymer component are made of are bisphenol A and epichlorohydrin. The second component is often an amine (a base) that catalyzes the cross-linking reaction. |
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Reply
| | | From: jimfee | Sent: 6/19/2004 6:54 AM |
StEvE,
I just love u! U r the greatest. I knew if any1 could help Manu, it would
be my Steve. Thanks bunches.
Jimfee
PS: I hope when I am taking Chem this Fall that u will be there w/me @
school (SMILE).
>From: "·Steve·" <[email protected]>
>Reply-To: "Chemistry Corner" <[email protected]>
>To: "Chemistry Corner" <[email protected]>
>Subject: Re: Thermo and Thermosetting Plastics
>Date: Fri, 18 Jun 2004 16:48:14 -0700
>
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Reply
| | | From: ·Steve· | Sent: 6/19/2004 7:29 AM |
If you are looking for reactions, you can also get some more from the PowerPoint slides at the Brooks/Cole web site for the organic textbook by Brown and Foote (under Online Problems on the left menu). Some of the slides are less useful; for example, the slide showing the Bakelite-forming reaction looks corrupted, at least on my computer, and a slide showing the crosslinking reaction of an epoxy resin prepolymer is not given. Nevertheless, you may find some of the slides showing polymer formation useful for your report. If you have access to a computer with PowerPoint installed, you can open the file in PowerPoint and copy and paste the graphics as needed. The file is fairly large, 874 K, and would not open when I was looking at polymer sites earlier. I imagine there are numerous other PP slide shows about polymers on the web, but I did not see any others just yet. Steve |
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Reply
| | | From: Manu | Sent: 6/19/2004 12:02 PM |
Hello Steve,
Nice to hear from you. I have gone through all the material
that you have directed me to. Found it very helpful. I haven't faced such a
situation ever, at least with respect to this assignment. I'm glad to be a
part of CC and look forward to being a part of the club. Right now, I have
to take care of the report. Thanks.
>From: "·Steve·" <[email protected]>
>Reply-To: "Chemistry Corner" <[email protected]>
>To: "Chemistry Corner" <[email protected]>
>Subject: Re: Thermo and Thermosetting Plastics
>Date: Fri, 18 Jun 2004 16:48:14 -0700
>
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Reply
| | | From: ·Steve· | Sent: 6/19/2004 6:32 PM |
OK Manu, good luck on the report! Steve |
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Reply
| | | From: Manu | Sent: 6/20/2004 5:27 AM |
Thank you Steve,
I've only got one question. If I was to write the
report at a high school level and had a section focussing on the Manufacture
of Thermo and Thermosets, what would I include? There seem to be so many
equations here, its making my head spin. The link to Michigan State
University was very helpful, so helpful it became a confusion factore. There
are details of so many processes, I'm not sure what to put in. And this
report is supposed to focus only on the chemistry, so physical properties
such as optical rarity etc. become unnecesarries. Could you help me out? And
there's one more thing. This is going to be a very small report. I need to
fit in Preparation, Propoerties and Uses into around 30 pages. What plastics
should I focus on? I hate to be bothering you. But I find nobody else able
to help. Thanks!
Manu
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Reply
| | | From: jimfee | Sent: 6/20/2004 6:21 AM |
Manu,
I told u that Steve would assist u in this report. I am glad that u r
finding the necessary info that u need. He will be there 4 u. Just give
him time.
Jimfee
>From: "Manu" <[email protected]>
>Reply-To: "Chemistry Corner" <[email protected]>
>To: [email protected]
>Subject: Re: Thermo and Thermosetting Plastics
>Date: Sat, 19 Jun 2004 21:27:25 -0700
>
_________________________________________________________________
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Reply
| | | From: jimfee | Sent: 6/20/2004 6:21 AM |
Plz let us know what u make on this report, okay.
Jimfee
>From: "Manu" <[email protected]>
>Reply-To: "Chemistry Corner" <[email protected]>
>To: [email protected]
>Subject: Re: Thermo and Thermosetting Plastics
>Date: Sat, 19 Jun 2004 21:27:25 -0700
>
_________________________________________________________________
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Reply
| | | From: ·Steve· | Sent: 6/20/2004 9:37 AM |
Hi Manu, yes, I think the difficulty with such a broad subject is narrowing it down sufficiently in order to keep your report to a managable length. Thirty typewritten pages is quite a lot of room, however!
If your report is to be introductory to some degree, then some basic properties and uses of plastics seen natural to include. If the emphasis is on the actual reactions involved in synthesizing various types of plastics, this will be much more difficult, because the reaction details would be a subject beyond most general chemistry textbooks and most Internet sites. Even organic textbooks typically devote only one chapter to polymers and reactions are discussed rather generally. But I am assuming that the requirements for your report are not so reaction-specific.
Here is a suggested general outline, with a couple more links worth looking at. Altogether, these sources have a lot of information in them, so you probably do not need to search extensively for more unless you need something specific. BTW, what kind of references do you have from your school, besides your chemistry textbook? Is the report intended to rely on Internet sources primarily?
The last section, Plastics and the Environment, may be unnecessary for your report, but it seemed like a nice way to conclude it.
Steve
III. Preparation of selected plastics
Here you can give the reactions for the preparation of a few types
A. Thermoplastics (select from PETE, HDPE/LDPE, PVC, PP, PS, or other)
B. Thermosetting plastic (Bakelite, U. Michigan cross-linking reaction)
IV. Manufacturing methods
(See the Encarta article starting on p. 1, bottom) |
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Reply
| | | From: jimfee | Sent: 6/20/2004 11:37 AM |
Steve,
U r so great!!! U r my "Chem" hero (SMILE). I am so glad 2 be apart of
this group.
Jimfee
>From: "·Steve·" <[email protected]>
>Reply-To: "Chemistry Corner" <[email protected]>
>To: "Chemistry Corner" <[email protected]>
>Subject: Re: Thermo and Thermosetting Plastics
>Date: Sun, 20 Jun 2004 01:37:55 -0700
>
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