bullet proof wood

[Phil Pascoe]

An extract from an article in today's Times -

A technique for crushing wood to a fifth of its natural thickness has resulted in a material strong enough to hold up skyscrapers and tough enough to stop a speeding bullet.

Scientists say that the “densified” wood has superior properties to steel and metal alloys. It is also light and cheap enough to be forged into a form of body armour.

Its most important use, however, is likely to be in building the cities of the future. Wood has obvious virtues for construction: it does not cost much, does not weigh much and does not do much damage to the environment compared with other materials.

Wooden skyscrapers have begun to spring up, including an 18-storey dormitory in Vancouver, Canada, a planned high-rise that would be the tallest building in Stockholm, and a 300m tower proposed as an addition to the Barbican complex in central London.

Yet wood’s usefulness to architects is limited by its structure, which is riddled with pores that compromise its strength. Researchers led by Jianwei Song at the University of Maryland made it three times denser but 12 times stronger by getting rid of the holes.

The first step involves treating the wood with caustic soda and sodium sulphite, much as a paper manufacturer might. This banishes much of the lignin and hemicelluloses that make up a lot of its bulk. The wooden blocks are then compressed at 100C, flattening their pores and raising their density from 0.43g per cubic centimetre to 1.3.
...

I've cut it short as it is undoubtedly copyright, but more info. can probably found easily enough.

 

[Droogs]

cool. exactly what 's needed for a shed then

 

[CHJ]

Its most important use, however, is likely to be in building the cities of the future. Wood has obvious virtues for construction: it does not cost much, does not weigh much and does not do much damage to the environment compared with other materials.

Wooden skyscrapers have begun to spring up, including an 18-storey dormitory in Vancouver, Canada, a planned high-rise that would be the tallest building in Stockholm, and a 300m tower proposed as an addition to the Barbican complex in central London.

Fire control should be interesting.

 

[monkeybiter]

Need to bung some hot pine in the vice and fire up the blow torch. What could go wrong?

 

[stuartpaul]

Fire control should be interesting.

Easy peasy, - bung in/coat with loads of chemicals and away you go!

I'm just wondering what forces are involved in 'condensing' wood to a fifth of it's thickness :shock: :shock: Some interesting furniture designs possible with thin, strong timber!

 

[monkeybiter]

And what about long term movement, slow moisture absorption etc. It could slowly explode.

 

[Brandlin]

Fire control should be interesting.

The full article published in nature today is an interesting read. The process involves boiling the wood in a sodium hydroxide sodium sulfite solution then compressing it as just 100 C, no pressure listed. This crushes all of the voids, lignum and other irregularities out of the wood and leaves you with much more densely packed cellulose fibres. A bit like carbon nano-tubes. That would also mean that whilst incredibly strong and dense those properties would still be dependent on the direction of the fibres (grain) and would make the material fairly flexible.

The article does state that although full testing is not complete that initial experiments show that the material is "not prone" to moisture absorption or rot like normal construction timber.

Fire control my well be much easier than current wood or steal buildings. By creating a much denser material its going to be significantly harder to burn - depending on what chemicals are left in it from the forming process(?). Talk to a few people about the characteristics of wood and steal frames in a house fire and you will find that a steal structure can be a bigger hazard than a wooden one - especially something like oak post and beam which are dense large section timbers. (My Musings - not from the article).

I am however imagining the Axminster "Dense" range of mega machines necessary to cut the stuff.

And why has no one made an "I've got dense wood" Joke yet?

 

[Tasky]

I'm just wondering what forces are involved in 'condensing' wood to a fifth of it's thickness :shock: :shock:

Oh, I expect the price of antique laundry mangles on eBay will go up soon... followed by the product launch of a Rob Cosman™ Wood Condensor™!!

 

[Garno]

And why has no one made an "I've got dense wood" Joke yet?

I think we all have but are unwilling to post due to the "banning stick" :shock:

 

[MikeG.]

Fire control should be interesting.

The full article published in nature today is an interesting read. The process involves boiling the wood in a sodium hydroxide sodium sulfite solution then compressing it as just 100 C, no pressure listed. This crushes all of the voids, lignum and other irregularities out of the wood and leaves you with much more densely packed cellulose fibres. A bit like carbon nano-tubes. That would also mean that whilst incredibly strong and dense those properties would still be dependent on the direction of the fibres (grain) and would make the material fairly flexible.

The article does state that although full testing is not complete that initial experiments show that the material is "not prone" to moisture absorption or rot like normal construction timber.

Fire control my well be much easier than current wood or steal buildings. By creating a much denser material its going to be significantly harder to burn - depending on what chemicals are left in it from the forming process(?). Talk to a few people about the characteristics of wood and steal frames in a house fire and you will find that a steal structure can be a bigger hazard than a wooden one - especially something like oak post and beam which are dense large section timbers. (My Musings - not from the article)......

Steel, not steal.

Correct. Timber buildings perform significantly better in fire than steel buildings.

 

[thick_mike]

Fire control should be interesting.

The full article published in nature today is an interesting read. The process involves boiling the wood in a sodium hydroxide sodium sulfite solution then compressing it as just 100 C, no pressure listed. This crushes all of the voids, lignum and other irregularities out of the wood and leaves you with much more densely packed cellulose fibres. A bit like carbon nano-tubes. That would also mean that whilst incredibly strong and dense those properties would still be dependent on the direction of the fibres (grain) and would make the material fairly flexible.

The article does state that although full testing is not complete that initial experiments show that the material is "not prone" to moisture absorption or rot like normal construction timber.

Fire control my well be much easier than current wood or steal buildings. By creating a much denser material its going to be significantly harder to burn - depending on what chemicals are left in it from the forming process(?). Talk to a few people about the characteristics of wood and steal frames in a house fire and you will find that a steal structure can be a bigger hazard than a wooden one - especially something like oak post and beam which are dense large section timbers. (My Musings - not from the article).

I am however imagining the Axminster "Dense" range of mega machines necessary to cut the stuff.

And why has no one made an "I've got dense wood" Joke yet?

Wasn’t there something a while ago about producing transparent wood using NaOH?

 

[Brandlin]

yes. the same research team i believe?

 

[SammyQ]

Steel, not steal.

Seconded MikeG. I'm glad to see I'm not the only one for whom 'typos' cause either wincing or wry amusement as juxtaposition of topic and the malapropism are ironic...

Sam