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Biopolymers-Based Nanocomposites: Functions and Applications
Published in Shiji Mathew, E.K. Radhakrishnan, Nano-Innovations in Food Packaging, 2023
Alka Yadav, Gauravi Agarkar, Luiza Helena Da Silva Martins, Mahendra Rai
Synthetic polymers are manmade macromolecules made up of numerous repeating monomer units (Maitz, 2015). Examples of synthetic polymers include polyamides (nylon), PVC, PE, PS, synthetic rubber, and teflon (Goudoulas, 2012; Mohan et al., 2016). Synthetic polymers are usually synthesized using petroleum and are made up of carbon–carbon bonds as backbone (Mohan et al., 2016). Synthetic polymers possess high mechanical, thermal, and elastic properties that make them efficient for a number of applications (Maitz et al., 2015; Mohan et al., 2016). A wide range of industries like automobile, textile, packaging, and paper depend on synthetic polymers (Bibi et al., 2019). Synthetic polymers are generally classified based on their response to heat. Thermoplastic polymers get softened by heating and could be transformed into desired shapes whereas thermosetting polymers remain intact at high temperature and pressure conditions (Maitz et al., 2015).
Recent Advancements in Microbial Degradation of Xenobiotics by Using Proteomics Approaches
Published in Vineet Kumar, Vinod Kumar Garg, Sunil Kumar, Jayanta Kumar Biswas, Omics for Environmental Engineering and Microbiology Systems, 2023
Neha Sharma, Smriti Shukla, Kartikeya Shukla, Ajit Varma, Vineet Kumar, Menaka Devi Salam, Arti Mishra
Plastics are artificially synthesized long-chain polymeric molecules. It consists of a variety of semi-synthetic, synthetic, organic, and inorganic compounds (Saminathan et al. 2014). Synthetic polymers are derived from petroleum oil. Various examples of synthetic polymers are polyethylene, nylons, polyvinyl chloride, and polystyrene. These are used in wrapping materials, garments, etc. These compounds are mostly accumulative in nature because of their insoluble nature (Jha et al. 2015). They pollute the aquatic bodies because of their toxic nature. These non-biodegradable plastics impose a serious threat to the environment by accumulating in large amounts because of improper waste management and uncontrolled disposal. Thus, they become a serious threat to our planet (USEPA 2005; Sharma and Dhingra 2016; Krueger et al. 2015) even though burying in landfill, incineration, and recycling are some of the plastic waste disposal methods.
Polyhexahydrotriazines: Synthesis and Thermal Studies
Published in Didier Rouxel, Sabu Thomas, Nandakumar Kalarikkal, Sajith T. Abdulrahman, Advanced Polymeric Materials, 2022
Nitish Paul Tharakan, J. Dhanalakshmi, C. T. Vijayakumar
A polymer is a large molecule or macromolecule, composed of many repeated subunits. Because of their broad range of properties, both synthetic and natural polymers play an essential and ubiquitous role in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as deoxyribonucleic acid and proteins that are fundamental to biological structure and function. Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. Their consequently large molecular mass relative to small molecule compounds produces unique physical properties, including toughness, viscoelasticity, and a tendency to form glasses and semicrystalline structures rather than crystals [1].
Effect of neem gum on water sorption, biodegradability and mechanical properties of thermoplastic corn starch-based packaging films
Published in Indian Chemical Engineer, 2022
M. Anubha, R. Saranya, C. Chandrasatheesh, J. Jayapriya
Starch is a very appealing cost-effective base for new biodegradable polymers because of its wide availability, ease of handling and ready castability into thermoplastic films (non-brittle) with the aid of plasticisers, such as water and poly-alcohols [7,8]. Typically, strong hydrogen bonds bind the starch chains, thereby rendering the starch granules insoluble in cold water. However, during transformation to form thermoplastic starch (TPS), the crystalline structure breaks, and the hydroxyl groups react with water molecules, thus making the starch particles partially soluble [9]. This hydrophilic nature of TPS imparts low water stability and high sensitivity to moisture, which hinder the efficacy of starch-based materials in packaging. Even though plasticising can improve the mechanical properties of starch polymers, they are still no match to the desirable properties of petroleum plastics. Therefore, a vast majority of studies on TPS involve the incorporation of different synthetic polymers such as Poly (vinyl alcohol), polyethylene, polyhydroxy butyrate in the matrix. However, most synthetic polymers are non-biodegradable in nature. To overcome this drawback, other ingredients, such as sugars and gums can be incorporated into thermoplastic starch-based films [10–12].
Ecotoxicological perspectives of microplastic pollution in amphibians
Published in Journal of Toxicology and Environmental Health, Part B, 2022
Mario A. Burgos-Aceves, Caterina Faggio, Miguel Betancourt-Lozano, Donají J. González-Mille, César A. Ilizaliturri-Hernández
Plastics are the most widely used synthetic polymer materials worldwide due to their versatility, adaptability, and multiple uses (Mathieu-Denoncourt et al. 2015). By 2020, a global plastics production of 367 million tonnes was estimated (Statista 2021). If the current trend in plastics demand continues, world production of 1.1 billion tonnes is projected by 2050. (Geyer 2020; United Nations Environment Programme 2021). Up to 40-60% of plastics produced ends up in landfills or is released into the natural environment (UNEP 2018; Bennett and Alexandridis 2021). Plastic leakage to the environment usually occurs during use and disposal, with large volumes lost due to littering and lack of environmentally sound waste management practices (United Nations Environment Programme 2021). Plastic debris mainly derives from industrial, agricultural, commercial, and municipal post-consumer plastic waste (Geyer 2020). Various chemicals, collectively known as additives or plasticizers, are added to the base plastic to provide desirable characteristics (https://www.plasticizers.org/plasticizers/), with bisphenol A (BPA) and ortho-phthalates among the most important ones (Mathieu-Denoncourt et al. 2015). Many of the additives are suspected to be endocrine-disrupting chemicals (EDCs), exhibiting carcinogenic actions (Calaf et al. 2020; Mathieu-Denoncourt et al. 2015), alterations in immune responses (Burgos-Aceves, Abo-Al-Ela, and Faggio 2021a, 2021b; Kimber 2017; Kimber and Dearman 2010), or associated with metabolic and cardiovascular disorders (Biemann, Blüher, and Isermann 2021; Jaimes et al. 2019; Tuculina et al. 2022). Once these contaminants reach the environment, plastics might degrade or break down into smaller pieces and eventually become microplastics (MPs); defined as plastic particles smaller than 5 mm (GESAMP 2015).
Biodegradable textile polymers: a review of current scenario and future opportunities
Published in Environmental Technology Reviews, 2023
Textile products are mostly composed of fibres that are made up of natural or synthetic polymers. Both these categories of fibres have different issues related to their biodegradation. Natural fibres are organically renewable and biodegradable, and their PCTW should not linger in the biosphere for a long time. Nonetheless, their biodegradability is often affected by the presence of synthetic dyes, finishes, and other treatments that these textiles receive during their manufacturing process for improved functionality and performance. Also, their degradation in natural soil and compost under biotic and abiotic conditions varies by their structure, morphology, time of exposure to soil medium, moisture, temperature, and pH [8,9]. On the other hand, synthetic fibres of petrochemical origin dominate the current global textile fibre market, producing around 113 million tons of fibres annually [10] (Figure 2). They play a necessary role in the textile industry due to their high performance and functionality, which many natural fibres lack. Polyethylene terephthalate (PET) also called polyester shares 54% of the textile market, while, cotton and other plant-based fibres make 22% and 6% respectively of the total market share, which ultimately also generates end-of-life TW in those proportions [10]. In general, synthetic polymers are resistant to biodegradation because of their high crystallinity and strength, which contributes to the accumulation of overall (macro and micro) plastic waste [11]. A large number of textiles used in the apparel industry are often blends of two or more synthetic polymers and/or natural and synthetic polymers making it difficult to recycle them as their degradation and recycling pathways vary chiefly. Thus, due to a lack of economically and structurally viable recycling options, most of the PCTW ends up in landfills.