Trees of South Africa – canopy tour

During a recent visit to South Africa part of my trip took in the Tsitsikamma Canopy Tour – zip lining through the canopy of trees along ten high suspension wires, one up to sixty meters long…

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Many of the platforms are built around giant Outeniqua Yellowwood trees that are up to 700 years old! Standing within the crown of these giants and looking down at the lush forest floor thirty meters below was an experience of a lifetime.

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We learnt a lot about the flora and fauna that live in the forest during the tour. Having made artworks inspired by one of the oldest trees in Trinity College Dublin (The Oregon Maple, now sadly fallen). One important fact that we learnt as we zipped along was that the reason that it was feasible to attach platforms and cables to these trees without damaging them was that their root structure was so shallow allowing the trees to be flexible and resilient to the many visitors who chose to see the trees from this height.

Tsitsikamma canopy tour

Bioplastic test: Day 3


On the third day of testing I decided to embed various types of fabrics into further test using the 2ml glycerol agar recipe.

To date I had been using the green coloured agarose so I decided to see what the material would work by using the clear agarose. It would also give me an opportunity to add some yellow food colouring to the mix. I decided that because the 4ml was interesting but too sticky I would also try to do a selection of samples using a 3ml glycerol agar recipe.

Again I added and stretched different types of fabric to the petri dishes.  See images below of the different tests undertaken.  Image directly below tests using the 2ml glycerol recipe. Image below that using the 3ml glycerol recipe. 

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20180524_103342Image above of clear bioplastic with embedded fabric samples.

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Above image of clear (left dish) and yellow food dyed (right dish) bioplastic.

Image above 2ml glycerol bioplastic sample brushed onto cotton netting.

Image above 2ml glycerol bioplastic sample  brushed onto cotton netting.  Artist stretching fabric to check capacity to stretch.  2ml glycerol sample quite brittle.  

Samples above 3ml glycerol sample, which was much more robust.  

Bioplastic testing: Day 2

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After drying the bioplastic tests overnight it was clear that the starch based one was really interesting and much more transparent than I was able to create on my own at home during last year’s experiments. I still felt though that I would have a problem trying to get in onto my fabrics in a controlled way. (see image above – starch bioplastic is the clear/ white material in the lower petri dish.  The top dish contains the (green coloured) agar bioplastic.)

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So we decided that we should focus our attention solely on the algae based bioplastics. The samples that we had created the day before had a lovely translucency; like looking through the see through coloured plastic sweet wrappers (see image above). Unfortunately the agarose mix without the glycerol was very fine and delicate after drying out. It was brittle, prone to tearing easily and very hard to scrape off the bottom of the Petri dish. So our final experiment yesterday was to test what would happen if we added glycerol to the algarose mix. To heighten the effect Conor decided to add 4ml of glycerol to the mix.

After drying in the oven at 65degrees from 12 until 6pm and being left on the bench overnight both algae samples were dry. However as earlier stated the algarose without the glycerol was deemed unsuitable as a material for this project. The sample with added glycerol was much more interesting and when pulled slightly had a little give or stretch in the material. It was however a little sticky to the touch though.

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So on day two of our sampling programe Conor decided to work with the algarose recipe and by adding 1, 2 and 4ml of glycerol test to see which if any had more workable properties.

So we made up 3 sample batches. Before I poured the solubulised liquid into the Petri dishes I added small strips of different types of fabric to the bottom of the Petri dish. The fabric samples were a nylon fixed gauze used in screen printing, a nylon lycra.  (see image below – left hand petri dish)

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It was decided before continuing any further testing of the bioplastic with the various sculptural fabrics that it was best to see which if the recipes would work best.

Two other tests were undertaken as well on this day.

To simulate the way the fabric would be working in a sculpture lycra mesh netting was stretched over the petri dish and held in place by an elastic band. The warm (4ml glycerol) liquid painted onto the stretched fabric and set pretty quickly. As I was hoping to eventually layer up the material onto the fabric we decided to test this out by painting a second layer on top of the first. (see image above – right hand petri dish)

Finally as we had talked about the lack of flexibility with the normal algarose mix Conor suggested that if we could add bubbles to the liquid mix before it set the bubbles would create a cushion and matrix inside the material that could allow it to flex better. He suggested working with Alka selzer could give us the effect we were looking for.

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So Conor crushed some of the tablet and put it on the Petri dish and pouring the slightly cooled down liquid algarose without the glycerol onto the powder. See image for result. He did something similar when he carefully added the remaining crushed tablet to the beaker of plain algarose over the sink. As he expected it bubbled and frothed up. Both samples were put into the oven to dry.

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Results from bioplastic testing: day 2:

Tests with basic agar bioplastic recipe with 1ml glycerol – too brittle and inflexible

Tests with agar bioplastic recipe with 2ml glycerol – a little bit of give

Tests with agar biopastic recipe with 4ml glycerol – stretchy but a bit sticky

Trees of South Africa – recent visit

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Storms River, Tsitsikamma National Wildlife Park, South Africa

During a recent visit to South Africa I was taken by the incredible trees that surrounded me during my walk to the Storms River suspension bridge, part of the wonderful Tsitsikamma Wildlife Park.

Having learnt a little “tree knowledge’ from TCD tree specialist David Hackett during the 2017 College Trinity Trees I was delighted to see some similar tree species to those that I had learnt about.

A black Ironwood – a blackish gum exudes from bark wounds. Image below.

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A real Yellowwood. Image below

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A Turkeyberry tree – with branches sporting incredibly large spikes standing sentry on the tree. Image below.

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A enormously tall tree that to my limited training seem to be a birch tree.  PHOTO-2018-08-02-13-07-33

And my favorite unidentified tree, who’s roots and branches seemed to defy gravity and have a life of their own. See Image below.

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Bioplastic testing – Day one

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Conor Buckley started our bioplastic journey to develop an art material for use in the Trinity Trees Project by explaining about the cellular make up of the different base materials we would be using. This was a great help for me to understand how the material would act and react depending on what you added to it.

We stared by talking about how one would make a starch based bioplastic.

Starch bioplastic: the recipe:

9.95grams of corn starch

60ml distilled water

5ml Acetic acid (vinegar) 5% solution

5ml glycerol (a light sensitive animal fat)

Cornstarch is a complex carbohydrate called a polysaccharide. It has a polymer chain with branches. When we add vinegar to the starch and water solution it cleaves the branches from the polymer chain separating them into whats called an amalose mix i.e. the starch and vinegar solubalise in water. When you add glycerol (the plasticiser), which is like an oil, it allows the chains to slide over each other. The stiffness or flexibility of the final product depends on the amount of glycerol we add to it. The more glycerol the more plasticised it becomes.

Starch bioplastic: the method:

Add water and corn starch to a graduated beaker. Add vinegar to create amalose. Add glycerol to plasticise. Put the beaker with all the ingredients over the heat and gradually increase the temperature from 100 to 140 and up to 160 degrees over about 10-15 minutes all the time stirring the mixture.

When the mixture changes from opaque to clear it is the time to scoop it out and spread it out on the chosen dish to dry. In our case we used petri dishes. Then the dish was placed in an oven set at 65 degrees to dry. For this starch how you dry it is important. If you leave it on bench to dry over a long period of time the top layer will dry faster and form a skin. Drying in the oven in @65 would allow for the material to dry more evenly.

Conor and I were delighted with the result, which was much more opaque than the samples I had created the year before. As most of last years samples ended up white in colour when I tried to add colour I ended up with varying shades of pastel colours. I had also tried many different ways of adding colour to this bioplastic. But now thanks to Conor’s knowledge I realise that what I thought was a good idea, adding acrylic (plastic based) paint to the mix, was in fact reacting with the cellular chains and making the material more brittle.

On the down side this and last years cornstarch bioplastics were very thick, lumpy and hard to spread evenly. If I were to use it to cover elements of my sculptures we would have to spread it when it was at its most liquid form when it was really hot and sticky As it looses heat quite quickly cools and becomes more unworkable it would be a tall order to use it as a material. A really fantastic matieral but unfortunately not one that I could use.

Two handy pieces of information that Conor imparted to me that I thought useful to share are:

1. When you are trying to optimise the mechanical properties of a material change one thing at a time. You don’t change the base amount of starch, water and vinegar components only the glycerol.

2. If you want to colour a bioplastic materials it is best to use three drops of food colouring and only after all the ingredients have been solubalised. If you add the colour earlier you might not be able to see the point at which the material changes from opaque to clear indicating that it is ready to use.

The second type of bioplastic we said we would explore was an Agar based one. 

Agar is a generic term for seaweed and alginate is a made by processing a type of seaweed. The algae base material that we are using is called agarose. This is a thermoreversable material i.e. it melts in water when you heat it up, sets when cool and can be reheated to liquid form again. It is important to note that the more times one heats and cools the material the weaker the material becomes. Conor explained what happens when the agarose is heated up in water. As it is made of nano scale helical shaped chains, they unravel when heated and straighten out and then return to the helical shape when they cool down.

In our initial experiment we just used the pure agarose.

Agar bioplastic: recipe 1:

agarose

1.5 grams agar

50 ml of water

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Agar bioplastic: recipe 2: agarose and glycerol version

1.5 grams agar

50ml of distilled water

4ml of glycerol

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Agar bioplastic: the method:

Measure out the 1.5 grams of agarose. Boil distilled water. Add agarose. Stir continuously over heat for 10-15 minutes until all the agarose strands have disappeared. Pour solubalised agrose into petri dish and leave to set. If glycerol is to be added do this after the agar has solubalised and before pouring into the petri dish.

Interestingly after describing what I was looking for from a bioplastic Conor suggested that by using a paint brush when this material was hot we could paint the bioplastic onto the fabric, which would then set and dry over time.

I also wondered if this material would be flexible enough to be able to move with the fabrics i use or would it be too brittle and tear. Conor decided to try and add some gylcerol to the mixture to act like a plastisier. He decided to start off with 2ml of glycerol, which we added to the solubalised mix. We planned to leave it over night to dry to see how that would look and work.

Another really interesting idea that Conor suggested on this first day is that he wanted to try adding bubbles to the mix. By adding bubbles to the recipe without glycerol he hoped to add an extra element of flexibility. So I was asked to bring in some alka selser for our next batch of experiments.

Sister tree felled today

I am saddened to say but due to safety concerns the second sister Oregon Maple tree was felled in Trinity College Dublin today.  Many tree specialists and contractors were on hand in a six hour mammoth task of felling the second tree. It was an eventful day full of much sadness, reverence and surprises.

I will post more photographs documenting the process over the coming days.