Volume 9, Issue 5

Pyrolysis technologies are a staple in plastic chemical recycling because of the robustness to contamination and existing infrastructure. Pyrolysis is already considered to be a reasonably mature technology with numerous pilot plants operating to pyrolyze plastic waste into fuels and chemicals. This chapter will describe the pyrolysis process and important process parameters, the types of plastics that are suitable for pyrolysis recycling, the mechanism of pyrolytic degradation of various plastics, the products derived from different plastics, companies that have successfully scaled pyrolysis recycling, and recent innovations in the technology.

In the past few decades, there has been increased interest in the use of natural fibers as reinforcement in bioplastic polymer composites because it is biodegradable. This is a result of the drawbacks of biodegradable polymer-based materials, which are brittle, intractable, and poorly water-sensitive. Natural fibers are chosen because they may be obtained organically, can be collected safely, and can be less expensive. In this work, cinnamon essential oil (CEO)/sugar palm nanocellulose/starch biopolymer composites were casted to investigate the morphological, water barrier and biodegradable properties. From the research, it shows water absorption increased regarding the plasticizer concentration. Besides, water vapor permeability (WVP) and solubility of the different concentration plasticizer used in the biopolymer shows an increasing trend due to high water content. All films degrade completely after the 12th day indicating the biodegradability of the film. Furthermore, seal strength for the lower concentrations of plasticizer shows the higher strength, while GS4.5 cannot be sealed due to high water contents. The images show the compatible films with slightly yellowish and transparent films. The variation of plasticizers did not affect the antibacterial activity of CEO inside the film forming solution. Overall, cinnamon essential oil (CEO)/sugar palm nanocellulose/starch biopolymer composites are good potential to enhance their suitability for food packaging applications.

Pollution is one of the most pressing issues of modern times. Effluent in the world is escalating due to the exponential growth in the industrial and agricultural sectors. The effluents contain heavy metals, pesticides, and inorganic substances ultimately leading to the deterioration of the ecosystem. Even though there are numerous wastewater treatment methods like adsorption, membrane separation, ion exchange, and physical, mechanical, and chemical treatments. They are expensive and have the risk of second-hand pollution. Biopolymers are alternate and superior to synthetic polymers due to their environmentally friendly approach and high efficiency in treating wastewater. The most prominent plant-based biopolymers for the treatment of pollutants are cellulose, starch, carrageenan, alginate, xylan, inulin, pectin, and tragacanth. These have their advantages and disadvantages in bioremediation. The mechanism of pollution removal has adsorption, flocculation, bridge formation, and electrostatic patches. They are biodegradable as they are natural in origin. They have proved to remove toxic pollutants like chitosan, pullulan, polyhydroxy alkonates and butyrates, dextran, starch and cellulose, polyvinyl alcohol and polycaprolactone, gelatin, collagen and wheat gluten, alginate, heparin, and pectin to name a few. Biopolymers are also sourced from diverse sources like agricultural wastes and well-known sources like plants, animals, and microbes. Biopolymer and its composites are utilized as coagulants and flocculants. They are cellulose graft polyacrylamide, anionic sodium carboxymethylcellulose, guar gum graft polyacrylamide, pectin polyacrylamide, starch, and tannin. Nanotechnology has led to the development of elite nanohybrid bio-adsorbents to actively remove pollutants. These nano adsorbents have been targeting pollutants like azo dyes, bovine serum albumin, cationic dyes, parabens, and methylene blue among others. Biopolymer composites are also widely used for diverse applications primarily due to their enhanced mechanical and thermal properties. Biopolymers from natural and synthetic sources can be modified and used as per the requirement.

With the urgent need to curb plastic pollution, research and development in biodegradable plastic have received a great deal of attention. Starch film is the most promising alternative to conventional petroleum-based plastic. It is biodegradable, affordable, and non-toxic to human health and the environment. Over the last decade, much attention has been paid to cellulose nanofiller-reinforcement to the starch-based polymer to produce nanocomposites. While the use of oat as nano-reinforcement is quite well known, there is still limited studies that investigate the use of nanocellulose for oat starch nanocomposite films reinforcement. There is an ample of possibility in improving the properties of oat starch films, and therefore utilizing nanocellulose reinforcement should be further investigated.

Miniaturization brings along significant advantages in the development, optimization, and implementation of chemical, biochemical, and related fields processes and assays. Given the reduced footprint, miniaturization allows a significant reduction in volumes to be processed while providing conditions for several conditions to be evaluated simultaneously. Accordingly, work can be performed timely in a space efficient manner, with significant costs savings. Microfluidics is the pinnacle of miniaturization, where the previous advantageous aspects are taken to the limit, with the added features of operation under well-defined and highly efficient mass and heat transfer environment. Additionally, microfluidic environment fosters process integration, monitoring, and control in a single framework. The present chapter aims to provide an overview of diverse applications of miniaturized devices, fabrication methods, and key issues in fluid dynamics that characterize a microfluidic environment.

Interest in nanocellulose has lately increased as a result of its benefits, such as renewable, biodegradable, high mechanical strength and valuable economically. In this regard, nanocellulose has been frequently employed as reinforcement for the enhancement of mechanical, thermal and biodegradation qualities of nanocomposite materials, such as thermoplastic starch. An overview of the use of pea starch that has been reinforced with nanocellulose for packaging and storage applications is given in this chapter. In comparison to standard sources of starch like maize, wheat and potatoes, it is consequently seen as a comparatively affordable source of starch. These composite polysaccharides (pea thermoplastic starch/nanocellulose) have the potential to replace traditional packaging composed of polymers derived from petroleum.

The visible deterioration of environmental health, as witnessed for a few decades now, has been the subject of debate and research for a long time. In the desperation to remove the pollutants from the available natural resources, countless physical, chemical, and biological methods have been introduced. However, they hold a few drawbacks and tend to alter the nature of the resources. To avoid intentional alteration, physical and biological methods are put-together to develop biopolymer-based membranes that would help the crisis and sort out the preferences. The technique includes trapping industrial carbon dioxide and other gases, drinking water treatment, wastewater treatment, desalination, reclamation, and reuse. Membrane technology is still a hot topic for new openings. Biocompatibility, biodegradability, and cost-effectivity of biopolymers are the greatest assets for developing technology. The efficacy of biopolymer-based membranes is covered in this chapter and their techniques in helping the environment.

Saponins are surface active glycosides which occur in plants as one of the secondary products of primary metabolism. Saponins have been reported to demonstrate antimicrobial, antioxidant and other biological activities. This study was designed to characterize the crude saponins extracted from stem bark of Parinari curatellifolia and to study the antibacterial and antioxidant activities. The saponin was extracted using standard protocol and was subjected to physicochemical characterization. Foaming and haemolysis tests as wells as determination of foaming index were conducted to confirm the presence of saponins. The solubility of the crude saponins was tested in various organic solvents at room temperature. The nature of the aglycone moiety was identified using Salkowski’s and Liebermann–Burchard’s tests. The glycone moiety was identified using Fehling’s test. Fluorescence test was conducted using UV light at 254 and 366 nm. The TLC separation profile was determined in suitable solvent system. The saponin was subjected to UV and FTIR finger printings using standard methods. Silver nanoparticles were synthesized and characterized using standard method. The saponins were evaluated for antioxidant and antibacterial activities using standard procedures. The foaming index was found to be 1666.6. The crude saponin showed different degrees of solubility in the solvents tested and was found to be highly soluble in methanol, ethanol and DMSO. Generally, the saponins were found to be insoluble in non-polar solvents. The aglycone moiety was found to be triterpenoidal in nature and the glycone was found to be a reducing sugar. The crude saponin produced fluorescence at 254 nm which indicated the presence of some chromophores. The TLC showed the presence of some metabolites with varying R f values. The UV analysis revealed two absorption peaks at 480 nm and 580 nm. The FTIR finger printing showed absorptions characteristic of some functional groups at different frequencies. The crude saponin and silver nanoparticles demonstrated free radical activity against DPPH free radical with IC 50 of 5.878 mg/mL and IC 50 0.2477 mg/mL, respectively while the H 2 O 2 radical had IC 50 of 5.750 mg/mL. The saponin inhibited the growth of Staphylococcus aureus with zone diameter of inhibition between 2 and 3 mm. The saponins are triterpenoidal in nature and demonstrated antioxidant and antibacterial activity.

“Itaconimide” is the members of imide (–CO–NH–CO–) family with reactive exocyclic double bond and it is easily obtained from the renewable resource i.e. D-glucose. The polymerization of various N -arylitaconimide (NAI) monomers with methyl methacrylate (MMA) have been reported to improve the glass transition temperature ( T g ) and thermal stability of poly(methyl methacrylate) (PMMA). In literature, these studies have been done mostly using conventional free radical polymerization methods, which restricts the architecture of copolymers to “random” only. The block copolymers of NAI and MMA are an important due to the combination of glassy PMMA and thermally stable poly(NAI), which offers its applications for higher temperature service. The architectural control of polymers in provisions of its topology, composition, and various functionalities is possibly obtained using reversible-deactivation radical polymerizations (RDRPs). In RDRPs, the concentration of free radical is controlled in such a way that the termination reactions are minimized (normally in range of 1–10 mol%), and not allowed to obstruct with the desired architecture. However, this is possible by achieving (or by establishing) a rapid dynamic equilibrium between propagating radical and dormant species (i.e. R–X). Among all RDRPs, the atom transfer radical polymerization (ATRP) is very popular and adaptable method for the synthesis of polymers with specifically controlled architecture. Two different architectures of NAI and MMA copolymers are reported using ATRP process. The effect of various pedant groups on the rate constants of propagation ( k p ) and thermal properties NAI and MMA copolymers is studied. The poly(NAI- ran -MMA)- b -poly(MMA) are stable up to 200 °C and degraded in three steps. Whereas, the poly(NAI- ran -MMA)- b -poly(NAI) are stable up to 330 °C and degraded in two steps. The density functional theory methods are used for calculation of equilibrium constants ( K ATRP ) for the ATRP process for the series of laboratory synthesized alkyl halides. A good agreement was observed between the experimentally determined and theoretically calculated K ATRP values. The mechanistic studies are carried for poly(NAI- ran -MMA) copolymer system using statistical model discrimination method along with 1 H decoupled 13 C NMR spectroscopy. For studying the mechanism of copolymerization of NAI and MMA via ATRP methods, “trimer model or penultimate model” will be more accurate than “dimer model or terminal model”.

Adansonia digitata is used in folk medicine as antipyretic, analgesic and as an antioxidant. The aim of the research was to study the physicochemical, antioxidant and acute toxicity profiles of the oil extracted from the seed nuts. Standard methods were used to ascertain the physicochemical parameters, antioxidant properties and the oral acute toxicity. The moisture content (MC), total ash (TA), acid insoluble ash (AIA), alcohol soluble extractive (ASE) and the water-soluble extractive (WSE) were: 4 %, 4 %, 0.33 %, 22 % and 20.67 % respectively. The oil yielded 15.29 %. The GC-MS revealed some fatty acids/esters. The oil was soluble in varieties organic solvents including petroleum ether, benzene, chloroform and others. Steroids were detected in the oil through qualitative phytochemical screening. The saponification value (SV) of 30.86 mgKOH/g, acid value (AV) of 140.25 mgKOH/g, Ester value (EV) of 109.39 mgKOH/g, iodine value (IV) of 104.05 gI 2 /100 g and specific gravity (SG) of 0.92 were obtained. The oil was safe up to a dose of 5000 mg/kg per body weight via the oral route at one dose level. The DPPH free radical scavenging activity of the oil showed the highest inhibition (92.3 %) at 3.30 mg/mL and the least inhibition of 86.6 % at 0.12 mg/mL. Therefore, this research has revealed that Adansonia digitata oil contain phytochemicals with free radical scavenging properties and the oil is not toxic.