Self Healing Plastic

One of the problems with plastic is that it is very difficult to repair once damaged. When there is a hole in your plastic bucket you cannot generally mend it. But researchers in Spain have developed the world’s first self healing plastic.

Cutting the self healing plastic

Cutting the self healing plastic

Researchers at the CIDETEC Centre for Electrochemical Technologies in San Sebastian, Spain have developed a plastic that once broken can heal itself. All the user has to do is put the pieces together and leave it at room temperature for a couple of hours, and the material kind of re-molds itself. The repair is said to be 97% perfect within a couple of hours, and perfect 2 days later, and a Youtube video demonstrating the strength of the repair is really quite incredible.

Plastics are made up of polymers, a long chain of molecules that are connected through chemical bonds. Natural polymers are everywhere. In nature, many polymers heal themselves when broken or sliced. Think of your skin when you have a small cut — as the two sides of the cut bind back together, you’re witnessing a self-healing polymer in action.

Synthetic polymers are just as common. Scientists started creating nylon and synthetic rubber to make up for the shortage of silk and rubber during World War II. PVC, polyester and many forms of plastic soon followed.

Putting the pieces together

Putting the pieces together

The Spanish have developed the first human-made self-healing polymer to function without a catalyst, they report in the Sept. 13 issue of the journal Materials Horizon. There are in fact other self healing plastics, but they require a catalyst to start the process (ultra violet light for example). Readers might know about self scratch repair paint, as advertised on TV. This paint is made from prawn shells, a fine example of a natural self healing material that uses the sun as catalyst.

The article states that “The idea behind this is to reconnect the chemical crosslinks which are broken when a material fractures, restoring the integrity of the material. This is expected to provide polymers with enhanced lifetime and resistance to fatigue”.

Testing the repair

Testing the repair

The researchers say this breakthrough will allow them to create stronger sealants, paints, adhesives and more. This could eventually lead to self-repairing pipes, bicycle tires and toys, among a million other possibilities.

Sounds great to me, and the less plastic we throw away the better.

A Miracle Material?

Plastic and its use on mass causes many problems as we all know. It is not biodegradable, made from oil, difficult to recycle and can be found almost everywhere floating in the sea or buried on land. What we need is something to replace it.

Over the last year researchers at the MMC in Paris have been working on a new material. What they have developed is something that might change the future of manufacturing.

See this short article for a more complete description.

Their material is called a vitrimer, it is organic, strong, lightweight and looks to bridge the gap between thermoplastics and thermoset products.

Will vitrimer replace plastic?

Could this be the future of manufacturing?

What this actually means to you and me is a material that is solid but workable across a wide temperature range, so doesn’t melt like plastic, break like glass, can be shaped after production (unlike plastic or other polymers) and easily recycled.

The material can be sculptured without the need for extreme heat, so can be liquefied and moulded and then bent once finished. This makes it an incredibly versatile substance for use in electronics, car manufacturing and many different fields of engineering.

Advantages include the possibility of not using moulds for large structures that produce shapes that cannot be adjusted. If necessary the form required can be made in-situ and manipulated to fit, something that is not possible with steel for example.

The constitution of the materials determines its rigidity, so you can make it like thick rubber with flexibility at room temperature or much more rigid, but it is not brittle and so will not snap.

Given the many problems associated with plastics and the weight issues of using steel, this material looks to offer the promise of a more versatile, easily recyclable, reusable and less polluting alternative, and certain sectors of the scientific community are calling it a wonder material.

One to watch I would say.

Second Hand Technology Finds

If you walk round Cambridge in Massachusetts in June, you find the streets filled with discarded belongings. The students are leaving Harvard, MIT, Boston University and all the others institutions and as they leave they abandon the things they cannot take with them by the side of the road. Many stacks of things have a little note or post it attached saying ‘take me’ or ‘free, working’, and it is very much part of the culture to take things.

On my final few days in Cambridge last week I walked the streets with my kids from one park to another, and I collected some interesting things, including some very interesting and expensive pieces of second hand technology.

A common sight on Cambridge Streets

I collected a pair of M Audio AV40 studio speakers, fully functioning and beautiful to listen to. List price $229.99. A few scratches on the top of one but obviously only had light domestic use. Into the back of the bike trailer they went and onward on our hunt.

Further down the road I picked up a large 27 inch LCD computer screen, again lightly used and well looked after. At least $200 if you buy it new, as its previous owner had done probably 9 months before.

I was fortunate enough to pass a young student as she emptied her office into a box on the street, so I collected 6 Moleskin divided folders ($26 each), 200 blank DVD’s and cases, about 60 blank CD’s and 2 nice moleskin notebooks. Into the trailer, the kids can walk.

Last year I saw bags of cables, modems and power units, and as I moved from Europe I took what I needed.

On this trip I also saw a 32inch flat screen TV but I couldn’t carry it, and a standard size LCD TV too but with no remote control. I left that where it was too and will explain why.

The thing about TV’s and monitors is that you have to pay $25 for the city services to pick them up, so many are abandoned. If you pick one up and it doesn’t work you have to pay to dispose of it, or leave it outside again for someone else to do the same. Either way not a great result. I also saw at least 10 old cathode TV’s, only one with the label to demonstrate that it had been paid for.

This started me thinking about the effect that a moving student population must have on the technology market and by extension the development of new products. Practically every student has a laptop, smart-phone, TV and high speed internet at home and these things are all paid for when they move to their university of choice. Producers must see a massive peak in September, and an associated rise in profits.

So this leads to the question of what happens to all of this stuff when they move on. In many cases they take it, but some cannot be transported and is left, either by the side of the road, dumped or left in the house.

As we all know the dumping of technology is extremely damaging, recycling a must but also ethically dubious, so how about something like the Cambridge model?

The model is also used here for cans and bottles. If you buy a beer in a bottle or can, the can or bottle has a value. If you take it back to the shop they recycle it and give you 10c back. I have seen the same model with plastic bottles in Scandinavia. The result of this scheme is that a business has grown up around collecting empty bottles etc from the bins, students in the case of Scandinavia and homeless people here.

Well, for however much you might not like the idea of going through somebody’s recycling bin for returnables, it looks like an extremely efficient form of recycling to me, and revenue for those people that really need it. And although I don’t do bottles you should see my well stocked office and hear my stereo at home!

Waste less!