**1. Introduction**

Globally, poor solid waste management remains an issue of concern in an environment due to inadequate policies, legislation, and public enlightenment on waste disposal [1]. The policies of the government on the environment are merely by mouth with poor implementation. The enlightenment programs remain poor with lack of needed coverage, intensity, and continuity so as to change the attitude toward the management of the waste disposal to the environment. However, the poor activities of government agencies for a safe environment may be attributed to improper funds, inadequate facilities and human resources, low technology know how, and taxation system [2]. Integrated solid waste management, 3R (i.e., reduce, reuse, and recycle) principles have contributed to minimization of waste in the environment. Successful means of solid waste management required an integration of technical, economic, and sociocultural involvement. The generation and disposal of plastic waste in environment have been undesirable activities that posed serious threat to humans' existence due to large quantities, low biodegradability, and its significant effect on economic growth [3]. In Japan, the waste quantities increased from 46 million tons in 2001 to 65 million tons in 2010 and are expected to have 0.7 kg/capita/day production in 2050 [4] and range from 0.44 to 0.66 kg/capita/day production in Nigeria [5]. The increase in solid waste generation in which plastics are included, in the urban area, is dependent on the increase in migration from rural to urban area, rate of consumption and standard of living, lifestyle, population density, and climatic changes [5, 6] (see **Table 1**).


#### **Table 1.**

*Solid waste generated [4, 5].*


#### **Table 2.**

*Recycling and generation of thermoplastics [11].*

In the USA, about 30 million tons of plastic wastes were produced in 2009 and only about 7% was recycled. Plastic wastes end up in landfills, beaches, rivers, and oceans, thereby causing environmental problems [7]. In the UK, about 5 billion of plastic wastes are generated every year [8]. In some developed countries like Japan, plastic waste is found to be the third major municipal and industrial waste [4] but second in developing countries like Nigeria [9, 10]. Based on production and utilization of plastics in Japan, about 90% of the plastics are thermoplastics (a type of plastic that undergoes a reversible chemical reaction for its curing and melting at high temperature) used for containers and packaging materials (films, sheets, bottles), daily necessities, household appliances, and automobiles as presented in **Table 2** and **Figure 1** [10, 11]. About 60–70% of thermoplastics are polyolefins, while PET, PS, and PVC make other compositions [12]. In Europe and developing countries, the incineration and landfill techniques used for management of plastics waste covered about 74%, despite advanced effect. Plastics are less expensive, weight saving, durable articles which can readily be molded into a variety of products and found useful in a wide range of applications [13], but its production and usage caused several environmental problems through disposal [14, 15]. Moreover, durability of thermoplastics is a consequence for disposal and accumulation in landfills.

Plastic recycling refers to a process of achieving useful products from waste plastics after its reprocessing or re-melting. Recycling is one of the most important actions currently available that provides a solution on environmental and ecological

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follows the pattern of **Figure 2**.

*Thermoplastic recycling process chart.*

*Thermoplastic Recycling: Properties, Modifications, and Applications*

threats posed by reduce oil usage, carbon dioxide emissions, and the quantities of waste requiring disposal [14, 16]. Despite plastic recycling remaining to be the best means of minimizing plastic waste, its quality is influenced by polymer cross-contamination, additives, non-polymer impurities, and degradation [17]. Recycling of thermoplastics posed many benefits such as provision of raw materials for manufacturing industry, reduced environmental threat to humans since it is non-biodegradable, minimized incineration and landfill issues, less energy consumption for sustenance, and it serving as a source of income and providing job opportunity [18]. However, economic factors that influenced the viability of thermoplastic recycling include the price, cost of recycling compared with forms of required disposal, suitability for specific applications, lack of information about the availability of recycled plastics, and quantity and quality of supply recycled thermoplastics compared with virgin thermoplastics [17, 18]. Thermoplastic recycling

*DOI: http://dx.doi.org/10.5772/intechopen.81614*

*Existing, recycled, and new entrants of plastic wastes [10].*

**Figure 1.**

**Figure 2.**

### *Thermoplastic Recycling: Properties, Modifications, and Applications DOI: http://dx.doi.org/10.5772/intechopen.81614*

*Thermosoftening Plastics*

In the USA, about 30 million tons of plastic wastes were produced in 2009 and only about 7% was recycled. Plastic wastes end up in landfills, beaches, rivers, and oceans, thereby causing environmental problems [7]. In the UK, about 5 billion of plastic wastes are generated every year [8]. In some developed countries like Japan, plastic waste is found to be the third major municipal and industrial waste [4] but second in developing countries like Nigeria [9, 10]. Based on production and utilization of plastics in Japan, about 90% of the plastics are thermoplastics (a type of plastic that undergoes a reversible chemical reaction for its curing and melting at high temperature) used for containers and packaging materials (films, sheets, bottles), daily necessities, household appliances, and automobiles as presented in **Table 2** and **Figure 1** [10, 11]. About 60–70% of thermoplastics are polyolefins, while PET, PS, and PVC make other compositions [12]. In Europe and developing countries, the incineration and landfill techniques used for management of plastics waste covered about 74%, despite advanced effect. Plastics are less expensive, weight saving, durable articles which can readily be molded into a variety of products and found useful in a wide range of applications [13], but its production and usage caused several environmental problems through disposal [14, 15]. Moreover, durability of thermoplastics is a consequence for disposal and

**Plastics Japan (%)**

Total 100 100

 Polyethylene 24.1 Polypropylene 23.1 Polyvinyl chloride 15.2 Polystyrene 7.0 5 PET 4.0 6 ABS 3.5 Others 13.3

**S/N Waste material Percentage (%)**

 Paper and cardboard 34 4 Organics 32 78 Plastics 17 9 Metals 6 4 Glass 5 3 Inorganic 4 1 Special waste 2 1

**Japan (%) Nigeria (%)**

Plastic recycling refers to a process of achieving useful products from waste plastics after its reprocessing or re-melting. Recycling is one of the most important actions currently available that provides a solution on environmental and ecological

**54**

**Table 2.**

**Table 1.**

*Solid waste generated [4, 5].*

*Recycling and generation of thermoplastics [11].*

accumulation in landfills.

**Figure 1.** *Existing, recycled, and new entrants of plastic wastes [10].*

**Figure 2.** *Thermoplastic recycling process chart.*

threats posed by reduce oil usage, carbon dioxide emissions, and the quantities of waste requiring disposal [14, 16]. Despite plastic recycling remaining to be the best means of minimizing plastic waste, its quality is influenced by polymer cross-contamination, additives, non-polymer impurities, and degradation [17]. Recycling of thermoplastics posed many benefits such as provision of raw materials for manufacturing industry, reduced environmental threat to humans since it is non-biodegradable, minimized incineration and landfill issues, less energy consumption for sustenance, and it serving as a source of income and providing job opportunity [18]. However, economic factors that influenced the viability of thermoplastic recycling include the price, cost of recycling compared with forms of required disposal, suitability for specific applications, lack of information about the availability of recycled plastics, and quantity and quality of supply recycled thermoplastics compared with virgin thermoplastics [17, 18]. Thermoplastic recycling follows the pattern of **Figure 2**.

#### *Thermosoftening Plastics*

Waste polymer recycling can be carried out by four approaches in accordance with ISO 15270, namely:


This chapter focuses on modifications of thermoplastic materials (HDPE, LDPE, PVC, PET, and PP) and mechanical recycling for enhanced properties, performance, and quality of the products for sustainable applications.
