A basic question: what's the difference between resin and plastic
Qing Xiaoliang
questions: what's resin and what's plastic? Is PE plastic or resin?
And what's the fundamental characteristic of rubber or plastic? Is the
crystalline state the criterion to determine whether a polymer is
plastic or rubber, or some other criterions, such as modulus, tensile
strength, Tg etc.
The elucidation is welcome. Thanks!!!
Pat March
Rolf Wissmann
materials based on macromolecules, like "Polyamide", opposed to
"metal" like Magnesium, for example, whereas "resin" is used to
refer to a specific, commercial grade of a plastic, like Ultramid*A3K,
or (Magnesium) AZ91.
There are basically 3 types of plastics:
rubbers, thermoplastics and thermosets
They differ in the degree of crosslinking, from none to little to a lot,
in terms of their mechanical properties, from elatic to plastic to rigid
and in terms of their typical enduse temperature range (ETR) relative
to their softening temperature (ST), from ETR>ST for rubbers to
ETR<ST for thermoplastics.
A 4th group of plastics are thermoplastic elastomers, which are thermoplastic
materials with elastomeric, i.e. rubbery-like, properties.
"Qing Xiaoliang" <gemi...@eyou.com> schrieb im Newsbeitrag news:1314acf8.01112...@posting.google.com...
Rolf Wissmann
the degree of crosslinking for rubbers, thermoplastics, thermosets
goes from little, none, to a lot ....
"Rolf Wissmann" <RolfWi...@t-online.de> schrieb im Newsbeitrag news:9u7rrt$5ea$03$1...@news.t-online.com...
John Spevacek
"Pat March" <insi...@worldnet.att.net> wrote in message
news:3C074E23...@worldnet.att.net...
> The two terms are loosely used interchangeably. Not very precise!
Unfortunately this is correct.
Based on all of my vast, extensive years of experience (all 12 of them!), it
seems like plastic is a broader term than resin. i.e., all resins are
plastics, but not all plastics are resins. I can think of a couple of
contexts that I have noticed over the years: 1) unprocessed beads are often
called resins, but after processing they are plastic (for example,
polypropylene resin vs. polypropylene film), and 2) reactive components
(polyesters, polyamides, ...) are more commonly called resins and not
plastics.
John
Qing Xiaoliang
>
Thanks for your explanation, but your post aroused me more
quesitons, as followed:
> There are basically 3 types of plastics:
> rubbers, thermoplastics and thermosets
>
> They differ in the degree of crosslinking, from none to little to a lot,
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
well, what do you call crosslinked rubber? Is is
belong to any catelogue of plastics?
> in terms of their mechanical properties, from elatic to plastic to rigid
> and in terms of their typical enduse temperature range (ETR) relative
~~~~~~ Is "endure" correct? sorry for
my ignorance about ETR, can you explain it further?
> to their softening temperature (ST), from ETR>ST for rubbers to
> ETR<ST for thermoplastics.
>
> A 4th group of plastics are thermoplastic elastomers, which are
~~~~~~~~~~~~~~~~~~~~~~~ I heard of
this, can you give me some examples?
Rolf Wissmann
Polymers
Plastics
Rubbers Thermoplastics Thermosets
resin A ...
resin B ...
By "ETR" I mean "Enduse Temperature Range" and wanted to express, that rubbers are mostly used above their softening temperature, which is below zero °C, to take advantage of their reversible elasticity, whereas thermoplastics are "always" used at enduse temperatures below their softening temperature (glass transition temperature for amorphous or melting point for semi-crystalline thermoplastics).
Examples for thermoplastic elastomers are Ionomers, like Surlyn* from DuPont, or thermoplastic ether ester elastomers (TEEE) like Arnitel* from DSM or others. See http://www.psrc.usm.edu/macrog/exp/rubber/sepisode/tpe.htm.
Hope this makes it clearer ...
"Qing Xiaoliang" <gemi...@eyou.com> schrieb im Newsbeitrag news:1314acf8.0111...@posting.google.com...
> "Rolf Wissmann" <RolfWi...@t-online.de> wrote in message news:<9u7rrt$5ea$03$1...@news.t-online.com>...
>
> > Thanks for your explanation, but your post aroused me more
> > quesitons, as followed:
> > There are basically 3 types of plastics:
> > rubbers, thermoplastics and thermosets
> >
> > They differ in the degree of crosslinking, from none to little to a lot,
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > ~~~~~~ Well, what do you call crosslinked rubber? Is is
> > belong to any catelogue of plastics?
>
> > in terms of their mechanical properties, from elatic to plastic to rigid
> > and in terms of their typical enduse temperature range (ETR) relative
> ~~~~~~ Is "endure" correct? sorry for
> my ignorance about ETR, can you explain it further?
>
> > to their softening temperature (ST), from ETR>ST for rubbers to
> > ETR<ST for thermoplastics.
> >
> > A 4th group of plastics are thermoplastic elastomers, which are
Larry Effler
interchangeably. You can refer to polyethylene both as a plastic and as a
resin. So, let's discuss the terms rubber and plastic.
A rubber or elastomer is typically an amorphous or nearly amorphous
polymer that is used at temperatures above its glass transition
temperature. In most cases the glass transition temperature is well below
room temperature. Since this means the material is subject to flow it is
typically of high molecular weight and is crosslinked after it has been
shaped into its final form. Examples of rubbers or elastomers are:
natural rubber, polyisoprene, polychloroprene, nitrile rubber, chlorinated
polyethylene (most commercial grades), etc.
A plastic is a polymer that is used at temperatures below its softening
point. In the case of essentially amorphous polymers, the use temperature
would be below the glass transition temperature. Examples of amorphous
plastics are polystyrene, polycarbonate, polyvinylchloride, poly(methyl
methacrylate), etc. For semi-crystalline polymers, the use temperature is
below the melting point. Examples of semi-crystalline plastics are
polyethylene, polypropylene, polyamides (nylons), etc.
Interestingly, it is the amorphous polymers that are "crystal" clear,
while semi-crystalline polymers tend to form opaque or translucent solids
due to the different refractive indices along their crystalline axes.
Larry Effler
Qing Xiaoliang
put all your advice in this map:
| (Tg for amorphous and
|softening point Tm for
semi-crystalline)
================================================================>Temperature
|
plastic <-----|----->rubber
\ /
(ETR for plastic) \ / (ETR for rubber)
\ /
Room temperature
and one more quesion: is there any material can be converted from
plastic into rubber?
and to Rolf Wissmann:
what does the blank refer to in your graph:
" Polymers
(blank) Plastics (blank)
John Spevacek
[snip]
By "ETR" I mean "Enduse Temperature Range" and wanted to express, that
rubbers are mostly used above their softening temperature, which is below
zero °C, to take advantage of their reversible elasticity, whereas
thermoplastics are "always" used at enduse temperatures below their
softening temperature (glass transition temperature for amorphous or melting
point for semi-crystalline thermoplastics).
I think Rolf means "END USE Temperature range".
Sorry to be so picky about this, but given that the original poster appears
not to have English as a native language, it might help clarify the issues
further.
John
--
"There will come a time when you believe everything is finished. That will
be the beginning." Louis L'Amour
The opinions expressed here are those of the author and may not be
representative of my employer.
Larry Effler
Qing Xiaoliang wrote:
> well, now the thing becomes clearer to me. As a summarization, I wanna
> put all your advice in this map:
> | (Tg for amorphous and
> |softening point Tm for
> semi-crystalline)
> ================================================================>Temperature
> |
> plastic <-----|----->rubber
> \ /
> (ETR for plastic) \ / (ETR for rubber)
> \ /
> Room temperature
>
> and one more quesion: is there any material can be converted from
> plastic into rubber? - Well yes and no. All plastics become rubbery above
> their melting point. However, you can do things to make plastics rubbery.
> The classic example is to add plasicizer to PVC. The plasticizer solvates the
> PVC chains and effective lowers the Tg to below room temperature. Viola!
> You've turn a hard plastic material into a flexible rubbery material. This
> can be done to a less extent to other amorphous polymers such as polystyrene,
> but doesn't work all that well with highly crystalline polymers.
> You can turn polyethylene into a rubbery material by chemically adding chain
> defects to the PE backbone. This is basically what is done with EPR, EPDM,
> chlorinated and chlorosulfonated polyethylene.
Rolf Wissmann
P o l y m e r s
/ Plastics \
/ | \
Rubbers Thermoplastics Thermosets
|
resin A ...
resin B ...
On a RELATIVE basis your "summary map" looks ok: Rubbers are mostly used above their softening point, whereas thermoplastics are used below their Tg or Tm. However, the softening point for rubbers is mostly far below room temperature, whereas Tg or Tm for most thermoplastics is far above room temperature.
"Larry Effler" <ljef...@ix.netcom.com> schrieb im Newsbeitrag news:3C0C39AB...@ix.netcom.com...
Joe Petipas
and a plastic is the ability of the resin to undergo a chemical
reaction. So epoxies, urethanes and melamines would be resins because
they must undergo a reaction in order to become a plastic. However
plastic pellets or powders like polyethylenes, ABS or vinyl may be
referred to as resins but it is a misnomer because they don't undergo
a chemical reaction they just get heated and molded into a different
physical form of the same plastic.
gemi...@eyou.com (Qing Xiaoliang) wrote in message news:<1314acf8.01112...@posting.google.com>...