Polymer densities: "You know your're a plastics engineer if..."

...you know the specific density of most polymers without having to look it up."

Still, having a repository of 318 polymers with their specific density at hand can help you in certain material selection decisions.

Enjoy the table and thanks for reading!

Thanks to Scientific Polymer Products for the data.

Greetings, Herwig

P.S. New to my blog - check out the start here section.

  

Chemical Name	Density (g/cc)
Poly(4-methyl-1-pentene)	0,83
Poly(1-pentene)	0,85
Ethylene/propylene/diene terpolymer-50% ethylene/4% diene	0,86
Ethylene/propylene copolymer-60% ethylene	0,86
Poly(1-butene)	0,86
Poly(1-hexene)	0,86
Poly(1-octadecene)	0,86
Polypropylene, atactic	0,866
Polymethylhexadecylsiloxane	0,88
Polymethyltetradecylsiloxane	0,88
Ethylene/butylene copolymer, dihydroxy terminated	0,88
Ethylene/butylene copolymer, monohydroxyl terminated	0,88
Poly(vinyl n-decyl ether)	0,883
Polymethyloctadecylsiloxane	0,886
Poly(1,4-pentadiene)	0,89
Poly(methyl n-tetradecyl siloxane)	0,89
Poly(methyl n-octadecylsiloxane)	0,89
Poly(vinyl n-dodecyl ether)	0,892
Poly(1,4-butadiene)	0,892
Polypropylene, isotactic	0,9
Polybutadiene, cis	0,9
Polybutadiene, cis & trans-36% trans	0,9
Poly(vinyl 2-ethylhexyl ether)	0,904
Polyisoprene	0,906
Polybutadiene, dicarboxy terminated	0,907
Poly(1,2-butadiene)	0,909
Polymethylhexylsiloxane	0,91
Styrene/ethylene-butylene, ABA block copolymer-29% styrene	0,91
Polydimethylsilane	0,91
Polybutadiene oligomer, acrylated	0,91
Polymethyloctylsiloxane	0,91
Poly(methyl n-octylsiloxane)	0,91
Styrene/butadiene copolymer-5% styrene	0,91
Poly(methyl n-hexylsiloxane)	0,91
Poly(vinyl n-octyl ether)	0,914
Poly(1-butene), isotactic	0,915
Styrene/isoprene, ABA block copolymer-14% styrene	0,92
Polyisobutylene	0,92
Poly(isobutylene-co-isoprene)-2.2% isoprene	0,92
Polyethylene, low density	0,92
Poly(vinyl sec-butyl ether)	0,92
Poly(vinyl isopropyl ether)	0,924
Poly(butadiene-co-acrylonitrile), dicarboxy terminated-10% acrylonitrile	0,924
Ethylene/vinyl acetate copolymer-18% vinyl acetate	0,925
Poly(vinyl n-hexyl ether)	0,925
Poly(vinyl n-butyl ether)	0,927
Ethylene/vinyl acetate copolymer-9% vinyl acetate	0,928
Poly(lauryl methacrylate)	0,929
Poly(dodecyl methacrylate)	0,929
Poly(isobutylene-co-isoprene), brominated-1,5% isoprene, 2.1% bromine	0,93
Polyethylene, oxidized	0,93
Ethylene/acrylic acid copolymer-5% acrylic acid	0,93
Ethylene/ethyl acrylate copolymer-18% ethyl acrylate	0,93
Polybutadiene, phenyl terminated	0,93
Poly(vinyl isobutyl ether)	0,93
Ethylene/vinyl acetate copolymer-14% vinyl acetate	0,932
Styrene/butadiene copolymer-23% styrene	0,935
Poly(butadiene-co-acrylonitrile), amine terminated-10% acrylonitrile	0,938
Styrene/butadiene, ABA block copolymer	0,94
Polydimethylsiloxane, ethoxy terminated	0,94
Ethylene/vinyl acetate copolymer-25% vinyl acetate	0,948
Polyethylene, high density	0,95
Ethylene/methacrylic acid ionomer, sodium ion	0,95
Poly(p-t-butyl styrene)	0,95
Poly(vinyl ethyl ether)	0,95
Poly(vinyl cyclohexane)	0,95
Ethylene/methacrylic acid ionomer, zinc ion	0,95
Ethylene/vinyl acetate copolymer-28% vinyl acetate	0,951
Ethylene/vinyl acetate copolymer-33% vinyl acetate	0,952
Poly(butadiene-co-acrylonitrile), dicarboxy terminated-18% acrylonitrile	0,955
N-Vinylpyrrolidone/vinyl acetate copolymer-30% N-vinyl pyrrolidone	0,955
Poly(butadiene-co-acrylonitrile), amine terminated-16.5% acrylonitrile	0,956
Poly(butadiene-co-acrylonitrile), dicarboxy terminated-21.5% acrylonitrile	0,958
Polyisoprene, trans	0,96
Poly(butadiene-co-acrylonitrile), dicarboxy terminated-26% acrylonitrile	0,96
Poly(methyl vinyl ether/maleic acid), monobutyl ester	0,962
Styrene/butadiene copolymer-45% styrene	0,965
Octadecene-1-maleic anhydride copolymer-20% maleic anhydride	0,97
Acrylonitrile/butadiene copolymer-22% acrylonitrile	0,97
Acrylonitrile/butadiene copolymer-21% acrylonitrile	0,97
Acrylonitrile/butadiene copolymer-29% acrylonitrile	0,97
Polydimethylsiloxane	0,97
Poly(n-octyl methacrylate)	0,971
Poly(tetramethylene ether) glycol	0,979
Ethylene/vinyl acetate copolymer-40% vinyl acetate	0,98
Ethylene/vinyl acetate copolymer-45% vinyl acetate	0,98
Polydimethylsiloxane, dihydroxy terminated	0,98
Polydimethylsiloxane, dimethylamine terminated	0,98
Polydimethylsiloxane, acetoxy terminated	0,98
Poly(propylene oxide), monoamine terminated	0,98
Acrylonitrile/butadiene copolymer-33% acrylonitrile	0,98
Poly(vinyl n-butyl sulfide)	0,98
Poly(vinylmethylsiloxane)	0,98
Polyoxytetramethylene	0,98
Poly(butadiene-co-acrylonitrile), vinyl terminated-16% acrylonitrile	0,985
Acrylonitrile/butadiene copolymer-38% acrylonitrile	0,99
Acrylonitrile/butadiene copolymer-27% acrylonitrile	0,99
Acrylonitrile/butadiene copolymer-45% acrylonitrile	0,99
Ethylene/vinyl acetate copolymer-50% vinyl acetate	0,99
Acrylonitrile/butadiene copolymer-31% acrylonitrile	0,99
Acrylonitrile/butadiene copolymer-44% acrylonitrile	0,99
Polymethylhydrosiloxane	0,99
Poly(1,2,2-trimethylpropyl methacrylate)	0,991
Poly(neopentyl methacrylate)	0,993
Poly(propylene oxide), diamine terminated	0,9964
Poly(propylene oxide), diurea terminated	0,9989
Poly(vinyl stearate)	1
Polydimethylsiloxane, chlorine terminated	1
Acrylonitrile/butadiene copolymer-43% acrylonitrile	1
Acrylonitrile/butadiene copolymer-51% acrylonitrile	1
Acrylonitrile/butadiene copolymer-41% acrylonitrile	1
Poly(propylene oxide)	1
Poly(t-butyl acrylate)	1
Poly(3,3-dimethylbutyl methacrylate)	1,001
Poly(propylene oxide), triamine terminated	1,003
Poly(propylene glycol)	1,005
Poly(1,3-dimethylbutyl methacrylate)	1,005
Poly(n-hexyl methacrylate)	1,007
Poly(dimethylsiloxane-co-ethylene oxide), AB block-25% dimethylsiloxane	1,007
Nylon 12 [Poly(lauryllactam)]	1,01
Poly(1-methylpentyl methacrylate)	1,013
Poly(1,4-butylene adipate)	1,019
Poly(vinyl propionate)	1,02
Poly(t-butyl methacrylate)	1,022
Poly(o-methyl styrene)	1,027
Poly(1-methylbutyl methacrylate)	1,03
Poly(isopentyl methacrylate)	1,032
Poly(n,n-dimethyl-3,5-dimethylene piperidinium chloride)	1,033
Poly(isopropyl methacrylate)	1,033
Poly(4-methylstyrene), monocarboxy terminated	1,04
Poly(4-methylstyrene)	1,04
Nylon 11 [Poly(undecanoamide)]	1,04
Poly(2-ethylbutyl methacrylate)	1,04
Poly(vinyl n-pentyl ether)	1,041
Poly(isobutyl methacrylate)	1,045
Poly(dimethysiloxane-co-diphenylsiloxane)-80% dimethylsiloxane	1,05
Polystyrene, monomethacrylate terminated	1,05
Polystyrene, monohydroxy terminated	1,05
Poly(vinyl methyl ether)	1,05
Polystyrene, 90% syndiotactic	1,05
Polystyrene	1,05
Poly(5-phenyl-1-pentene)	1,05
Poly(sec-butyl methacrylate)	1,052
Poly(n-butyl methacrylate)	1,055
Polyethyleneimine, epichlorohydrin modified	1,055
Polydiethoxysiloxane	1,06
Ethylene/vinyl acetate copolymer-70% vinyl acetate	1,06
Poly(2,6-dimethyl-p-phenylene oxide)	1,06
Poly(isobutyl acrylate)	1,06
Poly(isobornyl methacrylate)	1,06
Polyphenylene oxide	1,06
Poly(dimethylsiloxane-co-ethylene oxide), AB block-18% dimethylsiloxane	1,066
Poly(dimethylamine-co-epichlorohydrin), quaternized	1,07
Nylon 6/12 [Poly(hexamethylene dodecanediamide)]	1,07
Poly(diethylene triamine-co-adipic acid)	1,07
Polyethyleneimine	1,07
Poly(caprolatone)diol	1,07
Poly(caprolatone)triol	1,073
Poly(alpha-methylstyrene)	1,075
Nylon 6/9 [Poly(hexamethylene nonanediamide)]	1,08
Poly(ethylene oxide), diamine terminated	1,08
Poly(isopropyl acrylate)	1,08
Polyethyleneimine, 80% ethoxylated	1,08
Poly(n-propyl methacrylate)	1,08
Styrene/acrylonitrile copolymer-25% acrylonitrile	1,08
Nylon 6/10 [Poly(hexamethylene sebacamide)]	1,08
Nylon 6/6 [Poly(hexamethylene adipamide)]	1,08
Styrene/allyl alcohol copolymer-6% hydroxyl	1,083
Poly(vinyl butyral)-11% hydroxyl content	1,083
Poly(vinyl butyral)	1,083
Poly[2,2-propane bis[4-(2,6-dimethylphenyl)]carbonate]	1,083
Poly(ethylene sebacate)	1,085
Poly(n-butyl acrylate)	1,087
Butyl methacrylate/isobutyl methacrylate copolymer-50/50 copolymer	1,09
Poly(methyl m-chlorophenylethylsiloxane)	1,09
Poly(alpha,alpha-dimethylpropiolactone)	1,097
Poly(ethylene glycol mono-methyl ether)	1,097
Polystyrene sulfonic acid	1,1
Polyethylene, chlorinated-25% chlorine	1,1
Polysulfone, anionic	1,1
Polymethacrylonitrile	1,1
Poly(cyclohexyl methacrylate)	1,1
Poly(methyl m-chlorophenylsiloxane)	1,1
Poly(vinyl butyral)-19% hydroxyl content	1,1
Poly(ethyl methacrylate)	1,11
Polymethylphenylsiloxane	1,11
Poly(methylphenylsiloxane)	1,11
Poly(acryloxypropylmethylsilane)	1,11
Poly(p-cyclohexylphenyl methacrylate)	1,115
Vinyl alcohol/vinyl butyral copolymer-80% vinyl butyral	1,12
Nylon 6(3)T [Poly(trimethyl hexamethylene terephthalamide)]	1,12
Poly(vinyl methyl ketone)	1,12
Nylon 6 [Poly(caprolactam)]	1,12
Poly(ethyl acrylate)	1,12
Poly(2,2,2′-trimethylhexamethylene terephthalamide)	1,12
Poly(1-phenylethyl methacrylate)	1,129
Poly(2-ethyl-2-oxazoline)	1,14
Ethyl cellulose	1,14
Poly(2,6-diphenyl-1,4-phenylene oxide)	1,14
Polycaprolactone	1,143
Poly(1,2-diphenylethyl methacrylate)	1,147
Poly(t-butylaminoethyl methacrylate)	1,15
Poly(2-hydroxyethyl methacrylate)	1,15
Poly(styrene oxide)	1,15
Polyethylene, chlorinated-36% chlorine	1,16
Poly(diphenylmethyl methacrylate)	1,168
Poly(ethylene succinate)	1,175
Poly(benzyl methacrylate)	1,179
Styrene/maleic anhydride copolymer-75% styrene	1,18
Phenoxy resin	1,18
Poly(vinyl methyl sulfide)	1,18
Poly(methacrylic acid), sodium salt	1,18
Poly(ethylene adipate)	1,183
Poly(ethylene azelate)	1,183
Polyacrylonitrile	1,184
Poly(vinyl acetate)	1,19
Poly(1,4-cyclohexylidene dimethylene terephthalate)	1,196
Polydiphenoxyphosphazene	1,2
Poly(methyl methacrylate)	1,2
Poly(n-vinyl carbazole)	1,2
Polycarbonate	1,2
Bisphenol A polycarbonate	1,2
Poly[1,1-(1-phenylethane) bis(4-phenyl)carbonate]	1,2
Poly(ethylene glycol)	1,207
Poly(methylene-co-guanidine), hydrochloride	1,21
Poly(ethylene-co-chlorotrifluoroethylene)	1,21
Poly(phenyl methacrylate)	1,21
Poly(ethylene oxide)	1,21
Polyethylene, chlorinated-42% chlorine	1,22
Poly(methyl acrylate)	1,22
Polyimidazoline, quaternized	1,22
Polychloroprene	1,23
Cellulose propionate	1,23
Poly(vinyl formal)	1,23
Poly(methylene[polyphenyl isocyanate)]	1,24
Polysulfone	1,24
Poly[4,4′-isopropylidene diphenoxy di(4-phenylene)sulfone]	1,24
Poly(sec-butyl alpha-chloroacrylate)	1,24
Poly[methane bis(4-phenyl)carbonate]	1,24
Poly(n-butyl alpha-chloroacrylate)	1,24
Polyethylene, chlorinated-48% chlorine	1,25
Zein, purified	1,25
Polyoxymethylene	1,25
Poly(N-vinyl pyrrolidone)	1,25
Poly(cyclohexyl a-chloroacrylate)	1,25
Poly(diallyl isophthalate)	1,256
Cellulose acetate butyrate	1,26
Poly(diallyl phthalate)	1,267
Poly(tetramethylene isophthalate)	1,268
Poly[1-(o-chlorophenyl)ethyl methacrylate]	1,269
Polysulfide rubber	1,27
Styrene/maleic anhydride copolymer-50% styrene	1,27
Poly(isopropyl a-chloroacrylate)	1,27
Polyethylene, chlorosulfonated	1,28
Poly(vinyl alcohol)	1,29
Poly(n-propyl a-chloroacrylate)	1,3
Poly(methyl y-trifluoropropylsiloxane)	1,3
Poly[2,2′-(m-phenylene)-5,5′-bibenzimidazole]	1,3
Polyacrylamide	1,302
Poly(methyl alpha-cyanoacrylate)	1,304
Polybutadiene terephthalate	1,31
Cellulose acetate	1,31
Cellulose triacetate	1,31
Poly(2-chloroethyl methacrylate)	1,32
Poly(m-trifluoromethylstyrene)	1,32
Vinyl chloride/vinyl acetate copolymer-81% vinyl chloride	1,33
Poly(ethylene-2,6-naphthalenedicarboxylate)	1,33
Poly(ethylene phthalate)	1,338
Poly(ethylene isophthalate)	1,34
Poly(2,2,2-trifluoro-1-methylethyl methacrylate)	1,34
Vinyl chloride/vinyl acetate copolymer, carboxylated	1,35
Poly[thio bis(4-phenyl)carbonate]	1,355
Polyepichlorohydrin	1,36
Vinyl chloride/vinyl acetate copolymer-90% vinyl chloride	1,36
Poly(phenylene sulfide)	1,36
Poly(B-propiolactone)	1,36
Vinyl chloride/vinyl acetate copolymer-88% vinyl chloride	1,37
Methyl vinyl ether/maleic anhydride copolymer-50/50 copolymer	1,37
Poly(p-phenylene ether-sulphone)	1,37
Poly(3-chloropropylene oxide)	1,37
Poly(vinyl fluoride)	1,38
Poly(ethylene terephthalate)	1,385
Hydroxyethyl cellulose	1,39
Hydroxypropyl methyl cellulose	1,39
Vinyl chloride/vinyl acetate/vinyl alcohol terpolymer-91% vinyl chloride, 3% vinyl acetate	1,39
Poly(vinyl chloride), carboxylated	1,39
Methyl cellulose	1,39
Poly(ethyl a-chloroacrylate)	1,39
Polyimide	1,4
Poly(vinyl chloride)	1,4
Poly(acrylic acid)	1,41
Vinylidene chloride/vinyl chloride copolymer-5% vinyl chloride	1,41
Poly[2,2-propane bis[4-(2,6-dichlorophenyl)]carbonate]	1,415
Polyacetal	1,42
Poly[N,N’-(p,p’-oxydiphenylene)pyromellitimide]	1,42
Poly(4-fluoro-2-trifluoromethylstyrene)	1,43
Poly(p-hydroxy benzoate)	1,44
Poly(p-oxybenzoate)	1,44
Melamine cellulose	1.45-1.52
Poly(vinyl chloroacetate)	1,45
Melamine formaldehyde	1,48
Poly(3,3,3-trifluoroethylene)	1,58
Alginic acid, sodium salt (algin)	1,59
Cellulose nitrate	1,6
Poly(glycolic acid)	1,6
Polyisoprene, chlorinated	1,63
Vinylidene chloride/acrylonitrile copolymer-20% acrylonitrile	1,65
Poly(vinylidene chloride)	1,66
Poly(vinylidene fluoride)	1,76
Poly(hexafluoropropylene oxide)	1,91
Polychlorotrifluoroethylene	1,92
Poly[2,2-propane bis(4-(2,6-dibromophenyl)]carbonate]	1,953
Nafion 117, hydrogen ion form	1,98
Poly[2,2-hexafluoropropane bis[4-(2,6-dibromophenyl) carbonate]	1,987
Melamine	2
Phenolic resins	2
Poly(tetrafluoroethylene)	2
Poly(2,4,6-tribromostyrene)	2,1
Poly[tetrafluoroethylene-co-perfluoro(alkyl vinyl ether)]	2,15
Source: http://scientificpolymer.com/density-of-polymers-by-density/

Plastics Part Design: 10 “Holy” Design Rules For Injection Moulded Products I Design Guidelines For Injection Molded Parts I DFM

In today’s post I would like to give you 10 design rules which can be used as a checklist or little helper when finishing up your part design for injection moulded products and considering Design for Manufacturing (DFM).

Let’s start by listing all the 10 at once and then present detail information for each rule [1, 2, 3]:

1. Wall thickness as thin as possible
2. Continuous wall thickness to prevent accumulation of mass
3. Corners and edges with radius
4. Ribs designed for moulding: 40-60% of wall thickness for ribs
5. Avoid plane and even surfaces
6. Use draft angels http://upmold.com/draft-angle-chart/
7. Avoid undercut sections
8. No more accurate machining as necessary
9. Check for possibilities of function integration
10. Past performance of design can be guarantee of future results

1. Wall thickness as thin as possible: wall thickness has influence on the following factors:

• The allover part mass and therefore the material costs
• Cycle time
• Surface quality, warpage and shrinkage cavities
• Flow length
• Tolerances
• Stiffness build-up (use ribs)
• Orientation of molecules and additives such as glass fibers
   

Furthermore, designers seek for thin wall thicknesses since the latter enlarges the cooling time to the square (cooling time = wall thickness^2/ thermal conductivity). It has also the side benefit of saving material costs. Tolerances play an important role in terms of shrinkage and warpage. They are defined for plastic parts in several standards. One standard used in central Europe is DIN 16901. Here, you can find tolerances <1% for normal injection moulding, <0.6% for technical moulding and <0.3 for precision moulding. For achieving your production tolerances, the absolute value of your shrinkage is not as important as the shrinkage spread/deviation resulting through the process over time. Increasing the tolerances will not lead to a better part, it will most probably lead to a lower overall yield.

2. Continuous wall thickness to prevent accumulation of mass:

Different wall thickness influences mainly:

• Creation of porosity
• Sink marks
• Internal stresses (crystallization, shrinkage, polymerization) and warpage
  

When designing parts, it is important to consider that thick areas will take longer to cool down, especially when these are located far from the injection location and connected over thin wall areas. As a result, full freezing of the part does not happen in the packing phase and porosity and sink marks will be present in the final part. In the figure below, an example of how to connect the so called “eyes” to the main part.



3. Corners and edges with radius

In case you have a wall thicknesses change (thicker to thinner; thinner to thicker) or have corners, it is necessary to apply a radius for lowering the stresses.

The graph below shows the optimal radii as a function of wall thickness.

4. Ribs designed for moulding: 40-60% of wall thickness for ribs

There are several ways to increase the overall stiffness of your part:

• Increase the wall thickness: the cross sec­tional moment of inertia I = b*h^3/ 12 shows that increasing the wall thickness will increase the stiffness of your part to the power of three. It is more effective than changing the material. However, cooling time will increase significantly too. Therefore, the optimum needs to be found.
• Material selection: changing to a material with high modulus.
• Beads: usually with a factor of 1.8 times more effective than a rib in the same dimensions.
• Ribs: they are just getting effective when they are 5-10 times higher than the wall thickness and should be made with a thickness of 40-60% of the original wall. Injection moulding location and filling direction (molecular orientation) affects how ribs will perform in a later stage.

5. Avoid plane and even surfaces

The moulding of plane and even surfaces is one of the most challenging processes since the part tends to have sink marks and buckles. The reason for that can be a heterogeneous cooling process after moulding, or shrinkage due to variable wall thickness. Ineffective deployment of the holding pressure may also lead to buckling. It is difficult to replicate buckling since it is an unstable phenomenon.

6. Use draft angels

The cooled down polymer melt shrinks onto the mould cores which will be the inside of the final part. Draft angels are needed for the removal of the frozen part form the mould cores. A guidance on draft angels can be found below.

7. Avoid undercut sections

In nowadays injection tools is difficult to avoid undercut sections due to increased parts complexity. Polymers can withstand a forced ejection as long as the resulting stresses are within the yield stress of the polymers. As such the part can recover the deformation. Other ways of solving undercuts associated issues are:

• Movable sliders or collapsible cores
• Melting cores
• Utilization of split clamping design and subsequent laser weld of the resulting parts after moulding

For avoiding undercuts, creative design solutions are available. One of them is to use snap-fits.

8. No more accurate machining as necessary

When tolerances are set to high, quality will not automatically increase. Most of the times the opposite is the case: total yield of parts decreases. Therefore, parts need to have only the necessary tolerance to still fulfill their function.

9. Check for possibilities of function integration

Function integration for having off-tool parts are challenging for part designers and tool makers, since overall tool costs will increase. However, it allows keeping a competitive edge in high wage countries. Well known examples for function integration are:

• Metallic inserts like screw sockets and plugs
• Hinge joints: off-tool monkey
• Detachable screw joints
• Multi-component moulding
• Film hinges

10. Past performance of design can be guarantee of future results

On the stock market you get always the advice that past performance is not an indication for future performance. In case of plastics design this is not the case. Looking back at successful launched plastic products you can learn from them. Incorporation of proven design helps launch your part solution in a faster way.

Thanks for reading/watching and #findoutaboutplastics

Greetings

Herwig Juster

Interested in my monthly blog posts – then subscribe here and receive my high performance polymers knowledge matrix.

New to my Find Out About Plastics Blog - check out the start here section

🎤My Polymer Expert Talks Podcast

📹My YouTube channel

📚 My Polymer Material Selection book 

My personal website

My dedicated site for Polymer Material Selection

Literature:

[1] Keuerleber and Eyerer: Konstruieren und Gestalten mit Kuntstoffen, 2007

[2] Eric Larson – Thermoplastic Material Selection

[3] http://upmold.com/draft-angle-chart/