er & loss tan of some plastics in low freq., Req: high f

[mamali]

dear all,
here is a usefull info about plastics electrical parameters in low freq.
does anybody know same data in high freq?
specially, I am looking for PVC: It seems it has a er=3.2, and loss tan of .001; but some people told me it has a more loss on high frequencies;

yours,
Mat





polymer dielectric dielectric dissipation
constant strength factor
50Hz / 1Mhz (Kv/cm) 50Hz / 1Mhz (x10^-3)
-------- ----------- ----------- -----------
LDPE 2.29 / 2.28 370 .15 / .08
HDPE 2.35 / 2.34 -- .24 / .20
PP 2.27 / 2.25 240 .40 / .50
PVC-plasticized 4-8 / 4-5 270 80 / 120
PS 2.5 / 2.5 200-300 .1-.4/.05-.4
ABS 2.4-5/2.4-3.8 ~400 3-8 / 2-15
PMMA 3.3-3.9/2.2-3.2 140 40-60/4-40
POM 3.7 / 3.7 400 5 / 5
PTFE 2.1 / 2.1 480 .2 / .2
PCTFE 2.3-2.8/2.3-2.5 550 1 / 20
PA-6 3.8 / 3.4 400 10 / 30
PA-66 8 / 4 600 140 / 80
PC 3.0 / 2.9 380 .7 / 10
PET 4.0 / 4.0 420 2 / 20
PI 3.5 / 3.4 560 2 / 5
PUR-linear 5.8 / 4.0 >300 120 / 70
PUR-thermoset 3.6 / 3.4 240 50 / 50
PUR-thermoplas 6.6 / 5.6 300 30 / 60
CAB 3.7 / 3.5 400 6 / 21
Silicone 3.6 200 5-13 / 7


Another comparison:

polymer Dielectric constant / Dissipation Factor (x10^-3)

100 Hz 1000 Hz 1 Mhz 10 Mhz

ABS 2.8/5 2.8/6 2.8/8 2.8/7
PMMA 3.6/62 3.2/58 3.1/40 2.9/33
PC 3.1/1 3.1/1.3 3.1/7 3.1/11
PE 2.3/.1 2.3/.1 2.3/.1 2.3/.1
PA-6 4.2/31 3.8/24 3.8/31 4.0/20



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comments:

chemical name abreviation aka notes
------------- ----------- --- ------
polyethylene PE polythene-British!

CH2-CH2 monomer

HDPE High density PE
LDPE Low density PE

polypropylene PP replace one H in PE
by CH3

polyvinyl chloride PVC replace one H in PE
by one Cl atom

polyvinylidene chloride CPVC PVDC replace two H in PE
by two Cl

polystyrene PS replace H in PE by
a benzene ring

polyvinyl flouride PVF replace H in PE by
F atom

polyvinylidene flouride PVDF Kynar repace two H in PE
by two F atoms
*wire wrap insul.

polymethyl methacrylate PMMA Plexiglas
Lucite
Perspex (British)

polytetraflouroethylene PTFE Teflon replace all H in PE
by F atoms

polychlorotrifloroethylene PCTFE Kel-F replace 3 H in PE
with F one with Cl

polyamide 6 PA 6 Nylon 6

polyamide 66 PA 66 Nylon 66

polyamide-imide PAI Torlon

polyurethane PUR

polycarbonate PC Lexan

Polyacetal POM Delrin

polyethlene terephthalate PET Mylar co-polymer of PE

cellulose actetate butyrate CAB Butyrate

cellulose nitrate CN "Laquer" *typical constituent
laquers

acrylonitrile-butadiene-styrene ABS Cycopac ter-polymer of
polystyrene
* warning Jim Oliver says
this name may apply to
may many diff materials

polyimide PI Kapton

polyvinyl formal ? Formvar wire coating

 

[sergio mariotti]

Re: er & loss tan of some plastics in low freq., Req: hi

1) the dissipative loss due to dielectric rise linearly vs. frequency. I'ts the natural law for a dielectric with constant tanδ vs freq.
("rise linearly" means that the loss expressed in dB rise linearly)

2) the "slang" name used to call dielectrics, in some cases it isn't exaustive. Often some plastic are loaded with lossy materials and the name don't change.
I know that exists some "loaded teflon" composed by a large amount of PTFE and a small amount of "other" unknown materials. This may have an important role on tanδ

3) Generally, the εr and tanδ are constant vs freq. This is due to some consideration related to the iteraction wave to matter, too long to explain here.
So, why some one reports different εr at different freq.? Because εr depend largely on the measurement method.

The 1Mhz measurement method is closer to the µwave method than the 60 Hz measurement method.

 

[xxargs]

Re: er & loss tan of some plastics in low freq., Req: hi

dear all,
here is a usefull info about plastics electrical parameters in low freq.
does anybody know same data in high freq?
specially, I am looking for PVC: It seems it has a er=3.2, and loss tan of .001; but some people told me it has a more loss on high frequencies;

yours,
Mat


If i not remember really wrong - temperature is important if material
change phase form, ie. going from crystalin to clear form (light smokie
transparence for plastics in crystallin form, fully clear in amorf form in
higher, close to melting temperatur)

teflon is very much crystallin plastic (white colour) and polyeten i no
crystallic plastic (full clear) for example.

I have weak remember is PCV-cable not good in high temperatur
enviroment (> 80 degree Celcius) - is electric parameter change
to much compare to normal room temperatur...

xxargs

 

[mamali]

Re: er & loss tan of some plastics in low freq., Req: hi

tnx all,
well, would you please tell me more about PVC if you know? we want to use it as a shield on our antenna on a rocket which goes to about 100km above the earth surface. the shield has a distance of about 15mm from the antenna; i want to know if the electrical behaviour of PVC change to much with temprature; becouse if it is so, it will be a great problem; so, i suppose that PVC sheet has er=4 and loss tan of .001; is it rue? and how much it changes with tempreture.

tnx again for comments,
Mat