Abstract
Scientific research and technological innovation have brought major progress to mankind. However, the scale of human activities is enormous and exceeds the capacity of the environment to cope with the resulting impacts. Large environmental problems are a consequence. In order to evaluate potential harmful effects of technologies and products, they
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have to be systematically assessed, referred to as ‘technology assessment’. It is crucial that new materials and technologies are evaluated before they have entered the market, allowing measures to be taken if adverse effects appear. For novel technologies, the focus should therefore be ‘ex-ante’ (i.e. future-oriented). This thesis evaluates two new technologies, i.e. nanotechnology and white biotechnology. More specifically, it examines polymer nanocomposites, polymer photovoltaics and three chemicals produced with white biotechnology, i.e. polytrimethylene terephthalate, polyhydroxyalkanoates and ethanol. These technologies have been evaluated using a methodology referred to as ‘life cycle engineering (LCE)’. LCE comprises an environmental and an economic assessment and takes into account the entire life cycle from cradle (i.e. raw materials extraction) to grave (i.e. waste management). Since for laboratory stage technologies industrial process data are often not readily available, this thesis has also contributed to assessing industrial data from laboratory data to represent large scale industrial practice. Twenty-three different nanocomposites have been studied based on thermoplastic and thermosetting polymer matrices and organophillic montmorillonite, silica, carbon nanotubes (singlewalled and multiwalled) and calcium carbonate as filler. It appeared that for seventeen nanocomposites the environmental impacts expressed per kilogram decreased with increasing filler content. The conclusion is drawn that reinforcing polymers with nanoobject can have environmental benefits. An economic assessment has been conducted for a polypropylene- organophillic montmorillonite nanocomposite for different applications. It appeared that at a maximum price of €5000/tonne there are economic advantages of this type of nanocomposite for all studied applications compared to conventional materials. A concern of this technology however are the nanoobjects. If they are released from the polymer matrix they can be very toxic to humans. Therefore, exposure should always be avoided. A desktop study in this thesis showed that there are possibly risks that nanoobjects are not safely removed when nanocomposites are incinerated in municipal solid waste incinerators. Further research is required. Polymer photovoltaics (PV) are a promising new type of renewable energy. It appeared that the environmental impacts per watt-peak compared to mc-silicon PV are considerably lower. The costs are approximately 20% higher. The main challenge of this technology, however, is to increase the lifetime of the solar cells. A risk assessment has been conducted for chemicals produced with white biotechnology compared to petrochemical production taking into account risks to human health. Our results showed that risks are lower for biobased production. However, there are considerable uncertainties. Further research is required. Regarding methodological issues, it appeared that realistic data representing industrial practice can be obtained by using the material indices developed by Ashby and by combining laboratory data for material and energy use with data of industrial equipment
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