Biodegradable plastic in automotive

Recently, plastic composites consumption in automotive industry has experienced a spectacular growth with many applications in interior, exterior and under-hood components.  Pressure in fuel-efficient and low-polluting vehicles increases use of engineering plastics to make lighter weight products (Bellmann 1999; Allred 2000)[ Marsh, 2003, Mann D., 1999]. Amount of plastic used in current average automobile increased triple compared to those in 1975, with 14% to total weight, approximately 145.2 kg per vehicle in 2005 (Fig. 1.1b). Consequently, plastic waste from end-of-life of vehicles (ELV) becomes increase faster. In Canada and United States, there are about 11 million of vehicles with 1.6 million tones of ELV plastic part were dump into a landfill each year [Duval, 2007; Mohanty]. While in UK, around 2 million of vehicles reach the end of their life each year (Bismarck 2006).

Percentage of plastic components in each vehicle part to Total Plastic used

Percentage of Material Relative to Total Weight [Source: http://www.research.bayer.com]

The environmental awareness of the society has risen to the point that plastic waste should be reduced protection of natural resources and reduction CO₂ emission. Plastics make up significant proportion of the volume of domestic and industrial waste (10 - 30%), which degrade very slowly and equally resistant to natural process [Arostegui et al, 2008; Kolybaba, 2003]. They contain chemical substances that could present a hazard for the environment and also need more energy to produce [Marsh, 2003; Rosa, 2001]. Accumulation of plastic residue makes difficulty of water and oxygen to circulate and delays living of organic matters that cause damage to the environment and all living creatures.

Conventional method used as plastic waste reduction was disposal in land fill sites. Nowadays, the focus is on the reuse and recycle of waste materials because of ecological concern and limited space of land filling [Yoshioka et al, 2008]. By 2015, European Commission (EC) through European Guideline 2005/53/EG obligates that vehicles should be constructed of 95% recyclable materials with 85% recoverable through reuse or mechanical recycling  (Ashori 2008).   Even that reuse of plastic product could be the most environment-friendly method; there should be further checking to make sure that the material meets the required quality. Several problems also faced in recycling, such as difficulty to recycle due to complex polymer structure, loss of some advantageous properties and requirement of sophisticated technology or greater energy (Bellmann 1999; Allred 2000; Ashori 2008); Yoshioka et al, 2008; Selke, 2002]. Surveys in Germany have shown that basically only around 40% of the plastics used in a vehicle are fit for mechanical recycling (Bellmann 1999). Recycling conventional plastic composites releases dust and hazardous gasses (CO2, NO_x and SO_x) into the atmosphere.

To overcome those problems, the automotive industry should seek more environmental friendly material to minimize the creation of plastic waste. An innovative solution to the disposal of ELV plastic parts can be the use of biodegradable plastic. They are environmental friendly, eliminate hazardous substances into the soil and in the other hand provide appropriate mechanical and physical properties (Bismarck 2006; Ashori 2008)[Environment Australia, 2002; Malinconico, 2008].  Some of them are made from renewable resources therefore reduce the emission of hydrocarbon.