Why is plastic black?

[seriously disabled]

Plastic is almost everywhere ranging from plastic chairs, plastic wires, plastic pens, plastic loudspeakers etc etc. So many things are made of black plastic.

 

My question is: Why is plastic black? Is it because it contains carbon?

Edited August 7, 2009 by Uri

[CharonY]

Actually plastic polymers are normally not black unless dyed. Also, why should it be black due to the presence of carbon?

[seriously disabled]

Actually plastic polymers are normally not black unless dyed. Also, why should it be black due to the presence of carbon?

 

I don't know why, that's why I was asking. Most plastic is made from petroleum and is then heated in high-temperature furnaces and then it soldifies.

 

According to Wikipedia Petroleum is usually black or dark brown so I just thought plastic is black because it's made from petroleum.

Edited August 8, 2009 by Uri

[dr432]

maybe because charcoal is carbon and its black?

 

but i think the pure form of plastic is like milk gallons its clear

[iNow]

maybe because charcoal is carbon and its black?

 

No. As stated explicitly in post #2, the majority of dark plastics are dark because they were manufactured using dark dyes.

[dr432]

what i was responding to was:

 

why should it be black due to the presence of carbon?

 

and i think that like as charcoal (95% carbon), carbon is black so that's why i would think carbon powder is black.

and uri said its also black as petroleum although i think petroleum is really more hydrocarbon.

Edited August 8, 2009 by dr432
no reason.

[seriously disabled]

No. As stated explicitly in post #2, the majority of dark plastics are dark because they were manufactured using dark dyes.

 

And the minorty which are naturally dark, why are they naturally dark?

[John Cuthber]

"Most plastic is made from petroleum and is then heated in high-temperature furnaces and then it soldifies. "

It's a whole lot more complicated that that.

Almost all plastics are made from materials that are temselves made from fractions distilled from petroleum.

The distilled products are generally colourless and the compounds derived from them generally are too.

 

The only plastic I can think of that is "naturally" black is bakelite. but even in the case of bakelite the colour is due to degradation products- in principle the polymer could be made colourless.

[hermanntrude]

I made a plastic which was purple once. It was a star-polymer based on porphyrins. it's in "macromolecules"

[Cap'n Refsmmat]

and i think that like as charcoal (95% carbon), carbon is black so that's why i would think carbon powder is black.

and uri said its also black as petroleum although i think petroleum is really more hydrocarbon.

Diamonds are made of carbon.