Scion Bioplastics

September 2010

Technologies being developed at Scion to convert biomass to processable bioplastics

Bioplastics are materials with similar properties to some oil-based plastics but derived from biological feedstocks, typically agricultural waste residues from plants (crops, forestry or food processing) or from bacterial processing of waste water and other waste streams. In some cases they are both biodegradable and renewable and therefore have a more environmentally favourable image and are more likely to be ultimately sustainable.

Scion has been working on bioplastics for about 10 years. Their overall aim is to support New Zealand manufacturers in introducing bioplastics into their products whether they be whole products, a product component, or part of the packaging. Almost all plastics in New Zealand are imported so any use of locally produced bioplastics, or of biobased additives or fillers that can go into plastics and be processed as a plastic, can reduce our reliance on imports. It can also reduce the carbon footprint of the product, company and the country, and makes the product more acceptable on increasingly discerning overseas markets.

Use of local resources to make bioplastics, or some of the chemical additives or functional fillers that go into them, is a real major opportunity for New Zealand. Feedstock surveys by Scion have identified biomasses that could be used as sources of new fillers, fibres or feedstocks for polymers that go into making bioplastic products. Forestry was one sector identified as a big source for non food-mile biomaterials, along with residues from food crops and food processing, the horticultural industry, kiwifruit and other fruit waste, and industrial wastewater. Scion has developed a series of technologies to treat and convert these diverse biomasses into plastically processable materials or useful additive ingredients.

Dr Martin Markotsis, Polymer Scientist/Chemist with Scion, says that they have been working on the incorporation of biomass residues, plant products or byproducts from agriculture and horticulture into bioplastic items. One small example that illustrates the concept well is the kiwifruit “spife”, a spoon-knife combination originally made of conventional plastic and sold with retail packs of fruit for use in cutting and scooping the fruit.

“Zespri and Scion collaborated with a NZ plastics processor to produce a prototype ‘bio-spife’ made from a corn-based bioplastic such as polylactic acid (PLA) as well as residual kiwifruit waste and other eco-friendly ingredients. It is both renewable and likely to be readily compostable, and so provides a unique selling point that can reduce carbon footprints and be marketed to eco-conscious consumers,” he says.

“Another area we are working on is taking bioplastics and conventional plastics and reinforcing them with wood fibres as an alternative non-renewable high energy consuming materials like glass fibre. That has been used in chair base mouldings, and we are working with furniture manufacturers on this. Our Life Cycle Assessment has also shown some favourable comparisons to non-renewable options ”

“Through our association with the Biopolymer Network Ltd – a collaboration between Scion, AgResearch and Plant & Food Research – our team at Scion has also developed the technology to turn imported PLA bioplastic into a foam to replace expanded polystyrene foam. PLA is a compostable plastic made from fermented corn, and we have produced different shapes and sizes of the foam material that can be used, for example, in bean bag fillers, insulation, and in moulded packaging.”

For its bioplastic work Scion has plastics processing facilities including compounding, extrusion, injection moulding, thermoforming, film and foam production, which are all small scale versions of industrial plastics processing equipment. This means they can pre-treat, mix and blend formulations, and so extrude bioplastic pellets of the type that the plastics industry uses, and mould bioplastic articles, films or sheets.

One of the first items the team produced was a bioplastic pot for growing plants in, and they are still working on improved variations on this theme for use in the forestry industry – using, for example, forest wastes to make bioplastic pots in which to grow more seedlings.

The Bio-peg is another item. It is a replacement for a metal or conventional plastic ground spike used in securing erosion control matting, says Martin.

“Normally contractors would have to note the location of every peg and go back and collect them maybe a month later when the job was finished. We were asked if we could develop something that would biodegrade readily and safely, and the result was a peg and washer that are bioplastic composites – mixes of bioplastic, wood fibres and other natural or benign fillers,” he says.

“There was quite a bit of development required by Scion because, for example, PLA, the most common commercially available bioplastic, is too brittle and can’t be hammered without breaking. So we worked on a tougher formulation with the idea that if these things were left in the ground they would break down and there would be no negative effects.”

Use of bioplastics is still very small, less than 1% of the total market, but it is growing rapidly, according to Dr Alan Fernyhough, Team Leader, Biopolymer and Green Chemical Technologies at Scion.

“Major companies like Wal-Mart and Toyota are all driving to put more bioplastics into their products or to be supplied by packaging that is bioplastic. So our aim is to overcome the inherent property failures in existing commercial bioplastics – for example lack of toughness, melt strength, tearability, heat resistance, flame retarding, barrier performance etc – and do that wherever possible using New Zealand resources,” says Alan.

“A recent report said that the ultimate potential is to substitute 90% of conventional plastics with bioplastics. That might be some way off, but according to global industry forecasts by 2020 there will probably be somewhere between 10 and 30% bioplastic use. That’s at least a tenfold growth from where we are now.”

Although bioplastics can be more expensive than oil derived plastics, their prices have come down enormously in the past five years and the most available one today is about 30% more than commodity oil-based plastic. Increased volume of production and integration with growing biofuels infrastructure will continue the downward price trend and help them become more competitive.

For New Zealand, use of bioplastics provides opportunities to reduce imports of plastics, export food products in packaging from renewable resources, and find new uses for forestry, agricultural wastes, and other renewable biobased residues or resources. However, to get the greatest advantages in terms of cost and environmental impacts we need to be making some bioplastics or at least some of the components locally, says Alan.

“Longer term there is potential to produce significant volumes of our bioplastics requirements here. Scion has research projects on integrated biofuels and bioplastics production with bioplastics coming out of the same plant as the biofuels, so it is going to happen. Other chemical and polymer products can also be made, such as ingredients for coatings, adhesives and other products,” he says.

“How far away it is depends on how ambitious the New Zealand manufacturers are. It is still new territory for a lot of people, but if you look at what is happening in the USA and elsewhere there is a strong trend towards integrated corn ethanol and bioplastic production, and I would say it is inevitable here – maybe within 10 years and hopefully a lot sooner.”