Composite plastics from waste

I regularly find incredible surprises through social media. People doing great work, sharing, helping out.

One such surprise was Cibele Oliveira, from the University of Sao Paulo in Brazil. She got in touch in response to my scoop.it magazine, alerting me to work she has done on the manufacture of composite plastics using a mix of plastic and organic materials. Composite plastics are not particularly new.

The work that Cibele drew my attention to was the production of these composite plastics using a mix of plastics sorted from Municipal Solid Waste and bagasse. A paper presenting her work is contained in a book containing prize winning research into sustainable cities (pdf - go to page 166).

Since the work is published in Portugese, I did a rough and ready translation using Google Translate so that I could get a sense of what the work was about. Of course, any poor writing is entirely my fault, and I invite readers to offer corrections where necessary.

The thrust of the work is that composite materials were able to be manufactured from a blend of waste plastic and bagasse, without affecting too many of the mechanical strength properties. However, the rigidity and thermal stability are considerably affected, a thermal anti-oxidant would need to be used if the recycling composites were to be used in applications where thermal stability is important.

Bagasse reinforced composite plastics, in the proportion of 5%, 10%, 15%, 20% and 25% bagasse 

It is important work, and has many echos of the work being done by Waste for Life, a group that describes itself as:

Waste for Life is a loosely joined network of scientists, engineers, educators, architects, artists, designers, and cooperatives working together to develop poverty-reducing solutions to specific environmental problems. We use scientific knowledge and low-threshold/high-impact technologies to add value to resources that are commonly considered harmful or without worth, but are often the source of livelihood for society’s poorest members. Our twin goals are to reduce the damaging environmental impact of non-recycled plastic waste products and to promote self-sufficiency and economic security for at-risk populations who depend upon waste to survive.

We, ourselves, are not interested in profit, but are keen to disseminate a technology that upgrades waste plastic and natural fibers into composite materials for use in domestic products and building materials.

This is all really interesting work. To be able to take plastics of no value in MSW and make it into useful products, whilst at the same time assisting to resolve poverty, is an impressive undertaking. It is pure entrepreneurship, with very limited safety net in the event that it fails.

So thanks Cibele, and thanks to the contacts at Waste for Life who I've dealt with in the past.

Recycling of mattress fabric

A former post, "How do you recycle a mattress?", described the mattress dismantling process and identifies that steel and foam is recycled. Mattress fabric is not, generally.

I've been doing some research on how to recycle this fabric. That research has indicated that the fabric is generally a polyester blend, often blended with cotton. Which led me to ask if polyester fibre is recycled.

It turns out it is, and that is reasonably high profile for companies like Patagonia (working with with the Teijin ECO CIRCLE system from Japan). There is also Repreve in the US. Both processes take post-consumer fabric and reprocess it back into polyester fibre for remanufacture.

Teijin's Eco Circle Polyester Recycling process. Source: Teijin.

These processes chemically decompose the polyester and convert it into new polyester raw material. They work for clean polyester. I think. I'd love to know if they (or other) can also work for polyester blends.

In asking the question of networks, I was contacted by Nextek and advised:

We have recently finished a project in Europe where we have successfully recycled dyed polyester fibre, stripped out dyes and volatile and also upgraded the IV of the polyester resin for closed loop recycling back into fibre applications.

It will be interesting see what comes of it, and the answer may be the subject of a future post.

In the interim, it is good to know how much work is being done to recycle polyester. This has classically been described as recycling PET bottles back into clothes, and to be honest, I could never really reconcile this. Think about how many PET bottles are discarded and contrast that with the amount of clothing made with PET - I can't imagine they are in the same game.

But taking polyester fabric and reforming polyester fabric seems much more sane. It matches life cycle, it looks to close a loop reasonably tightly. Repreve has a great summary of what their process saves in the manufacturing process. To a non-polyester expert, this all seems pretty impressive.

A summary of how the Repreve process conserves natural resources. Source: Repreve

Perhaps asking the question of what can be done with mattress polyester blends can nudge the industry into finding solutions (if they don't already exist). 

That, in turn, could could find a path for a whole heap of additional resources to be returned to the manufacturing process rather than landfilled. And, done locally, it enables every city of reasonable size to have its own polyester resource that can be used to build in all sorts of fabrics.

The world of waste without us

Reading (again) the book "The World Without Us" by Alan Weisman, I'm reminded that we leave some very long-lived legacies.

One is obvious. High strength radioactive waste will be around for a long, long time. It is pretty unlikely to be able to be contained in a world without us, and so it will cause radioactive hotspots that last a long, long time. That is bad enough, but kind of obvious.

The thing that struck me was that plastics are also very long lived. There are (currently) no bacteria that are able to decompose most plastics, and so they will be around a long time. Weisman dedicates a chapter to this discussion (Polymers are forever), including a discussion of the Great Pacfic Garbage Patch. A startling fact reported is that, of the 1 billion tonnes of plastic produced in the 50 years, every bit remains in the environment (except for a small amount that's been incinerated).

It's not like, paper, which largely decomposes. Except when it is deep in landfill, when it can also be very long lived. Work done by William Rathje (who, I have just learned in researching this post, die just four months ago) found readable newspapers from the 1930s in current landfills. Incidentally, Rathje termed his work "garbology".

So we are here blithely using some of the most long-lived material in the world for such transient applications as single use packaging. This is why we are seeing such an explosion of community groups trying to reduce plastic use, seeing things like Two Hands Project, Plastic Free July and many others. These messages get real resonance, indicating that people care. They are important, as they try to reduce plastic creation.

Another avenue, perhaps a secondary mechanism, is to remove plastic once it's created and collected. One avenue that tickles my fancy is a small scale plastic-oil convertor. Pointed out by my good cyber-friend Ken, the "Blest Machine" converts plastic (except for PET) back into its constituent oil. For every kilogram of plastics, about a litre of oil is produced which can be further refined to diesel etc. The units are pretty expensive, but a great first step.

Blest Machine - plastic to oil conversion

The Blest website has more information, but it strikes me as a pretty cool idea for creating fuel where plastic is abundant. Thanks Ken!

I remember first reading The World Without Us and seeing plastic in a whole new light. What just another product, a bit challenging in terms of waste operations, became one of the most extraordinarily insane materials in use.

The world of waste without us...some pretty nasty radioactive hotspots and a general smear of plastic throughout the environment, including within animals as the plastics get smaller and smaller.

Plastics on water, source Green Team RSMAS