A world first for University of Canterbury
Shusheng Pang
August 16, 2012
A University of Canterbury (UC) professor has produced a world first recycled plastic and sawdust composite building
material.
Shusheng Pang, director of UC’s wood technology research centre, has discovered a practical use for some of the 160,000
tonnes of unwanted plastic that goes to New Zealand dumps each year. The product would be suitable for decking, joinery
and panelling in a house or outdoor playgrounds as a substitute for chemically-treated wood.
``New Zealand uses at least 200,000 tonnes of plastics a year and only 35,440 tonnes are recovered with the rest ending
up in landfills. Wood in its original form swells when it gets wet and shrinks when it is dried,’’ Professor Pang said
today.
``If not properly designed and constructed, wood stability and durability can be a concern for wooden structures such as
leaky houses. Currently wood is chemically treated for building purposes if high durability is required.
``I have developed a build material combing recycled plastics and wood. This material, wood- plastic composite, is more
stable and durable than original wood and stronger than original plastics. The wood-plastic composite is processed
through mixing and hot pressing in mould. The final form of the product is either in a flat sheet or in complex moulded
forms.’’
Pang, who will deliver a free public lecture on the breakthrough at UC campus on August 29, is in discussion with
potential partners to build a plant for production of the wood-plastic products, probably based in Christchurch.
Plastics such as supermarket bags, milk bottles and other food containers as well as the sawdust of radiata pine will
end up as a strong recycled building material.
Although a wood-plastic product has been applied in North America and Europe before, this is new using recycled plastic
for building materials.
``As well as producing a better building product, it also helps the environment using recycled plastic which will reduce
the landfills. The wood-plastic composite remains stable when exposed to water and durable in intense UV exposure and
freezing-thaw conditions. It would make a great building material,’’ Pang said.
Living in chemical-free homes partly made from sawdust and recycled plastic was a giant step closer but it has taken him
and his UC research team five years to reach this stage.
``We want to bring our product to market so Kiwis can use alternative materials they use to build their homes. At the
same time, we've discovered a practical use for the plastic clogging up our landfills. It's very much a win-win
solution.’’
ends