Plastics are one of the essential materials due to their low cost and properties. Plastics are used almost everywhere including food packaging, home appliance, agriculture, automobile, electrical insulators, medical instruments, etc. However, due to the low biodegradability of conventional plastics, they remain in the environment for a very long time and thus pose a serious threat to our environment. Getting rid of these plastics is very difficult. The burning of plastics produces harmful chemicals that negatively impact the environment (e.g., global warming) and human health. Plastic management via recycling is an incomplete measure to address the environmental impacts of plastic. Therefore, there is a demand for developing alternative plastic materials that will be more environmentally friendly. Bioplastics have attracted much attention as a potential replacement for conventional plastics. This chapter will focus on the development, properties, and applications of various bioplastics. The biodegradability of the bioplastics will also be discussed.
TopIntroduction
Plastics are ubiquitous in our society. It is estimated that 407 million tons of plastic were produced in 2018. (Sushmitha et al., 2016) Only 7% of this is recycled, and the rest is dumped into ocean and landfills. Conventional plastics degrade very slowly, (DiGregorio, 2009) and remain in the environment for a very long time. Thus, these plastics pose a serious threat to
Figure 1. Various bio-based and biodegradable plastics
freshwater, natural terrestrial, and marine ecosystems. Bioplastic has attracted much attention as a potential replacement for conventional plastics. The increased interest is due to several advantages of bioplastic over conventional plastics. One advantage is their biodegradability. For example, bioplastic such as polyhydroxyalkanoate (PHA) has been shown to be completely biodegradable. (Eubeler et al., 2010) Other advantages include their adaptability to the human body, reduced reliance on fossil fuel, etc. Bioplastics can be bio-based and made from biomass and renewable resources such as corn starch, potato starch, rice straw, vegetable oil and fat, etc. However, all bio-based plastics are not biodegradable (Figure 1) such as bio-based-polyethylene (Bio-PE), bio-based-polypropylene (Bio-PP), etc. The rate of biodegradation depends on the bioplastics. Thus, bio-based and biodegradable plastics include polylactic acid (PLA), (Auras et al., 2004) PHA, (Liu et al., 2010) cellulose, (Privas et al., 2013) starch, etc. (Mostafa et al., 2014) It is worth mentioning that starch, cellulose, etc. are not plastics in their native form. However, they can be converted to plastic through innovative fermentation and polymer technology. Moreover, some protein-rich sources such as soy, (Alvarez-Castillo et al., 2018) wheat, (Jerez et al., 2005) pea (Perez-Puyana et al., 2016) have also been used for making bioplastic materials and films. Several bioplastic materials such as PHA, cellulose, starch, etc., have been used in food packaging. Bioplastics also have great potential application in the textile industry. However, there are some challenges to the growth of the bioplastic market. These include interference with food sources and high production costs. The issue with interference with food sources can be addressed by using non-food resources. Also, different biological alternatives such as bioplastic production from microalgae consortia has been reported. (López Rocha et al., 2020) Much research is being done to optimize the production and make bioplastic economically viable. This chapter will focus on the development, properties, and applications of various bioplastics. The biodegradability of the bioplastics will also be discussed.