Non-biodegradable Polymers Research Articles

An Experimental and Numerical Investigation into the Durability of Fibre/Polymer Composites with Synthetic and Natural Fibres.

Progress in engineering research has shifted the interest from traditional monolithic materials to modern materials such as fibre reinforced composites (FRC). This paradigm shift can be attributed to the unique mechanical characteristics of FRCs such as high strength to weight ratio, good flexural strength, and fracture toughness. At present, synthetic composites dominate the automotive, aerospace, sporting, and construction industries despite serious drawbacks such as costly raw materials, high manufacturing costs, non-recyclability, toxicity, and non-biodegradability. To address these issues, naturally occurring plant fibres (such as jute, hemp, sisal) are being increasingly researched as potential reinforcements for biodegradable or non-biodegradable polymer matrices to produce environmentally friendly composites. In this study, sisal fibres were selected owing to their low production costs, sustainability, recyclability, and biodegradability. The hydrothermal ageing and mechanical characteristics of sisal fibre-reinforced epoxy (SFRE) composites were determined and compared with glass fibre-reinforced epoxy (GFRE) synthetic composites. Moreover, a first-of-its-kind numerical model have been developed to study the hydrothermal ageing and mechanical characteristics of SFRE, along with GFRE, using ANSYS software. Moreover, microstructural analysis of flexural tested GFRE and SFRE samples were carried out to identify the microstructural properties of the composites. Both experimental and numerical results exhibited an influence of short- or long-term hydrothermal treatment on the flexural properties of glass and sisal fibre-based composites. In the case of GFRE, the moisture uptake and fibre-matrix de-bonding existed, but it is less severe as compared to the SFRE composites. It was found that the dosage of sisal fibres largely determines the ultimate mechanical performance of the composite. Nonetheless, the experimental and numerical flexural strengths of SFRE were comparable to GFRE composites. This exhibited that the SFRE composites possess the potentiality as a sustainable material for advanced applications.

Strategies of Recovery and Organic Recycling Used in Textile Waste Management.

Post-consumer bio-based textile wastes are any type of garment or household article made from manufactured bio-based textiles that the owner no longer needs and decides to discard. According to the hierarchy of waste management, post-consumer textile waste should be organically recycled. However, there is still a problem with the implementation of selective collection of textile waste followed by sorting, which would prepare the waste for organic recycling. A technically achievable strategy for sorted textile waste materials consisting of only one type of fiber material, multi-material textiles are a problem for recycling purposes. Waste textiles are composed of different materials, including natural as well as synthetic non-cellulosic fibers, making bioprocessing difficult. Various strategies for recovery of valuable polymers or monomers from textile waste, including concentrated and dilute acid hydrolysis, ionic liquids as well as enzymatic hydrolysis, have been discussed. One possible process for fiber recycling is fiber recovery. Fiber reclamation is extraction of fibers from textile waste and their reuse. To ensure that organic recycling is effective and that the degradation products of textile waste do not limit the quality and quantity of organic recycling products, bio-based textile waste should be biodegradable and compostable. Although waste textiles comprising a synthetic polymers fractions are considered a threat to the environment. However, their biodegradable part has great potential for production of biological products (e.g., ethanol and biogas, enzyme synthesis). A bio-based textile waste management system should promote the development and application of novel recycling techniques, such as further development of biochemical recycling processes and the textile waste should be preceded by recovery of non-biodegradable polymers to avoid contaminating the bioproducts with nano and microplastics.

Influence of pandemic waste face mask on rheological, physical and chemical properties of bitumen

Recently, COVID-19 has appeared as an international pandemic, leading to serious risks for humans. Using face masks is one of the most common measures in a wide-ranging prevention program that could control the COVID-19 dissemination. Face masks are typically composed of non-biodegradable and non-renewable polymers based on petroleum, which are harmful to nature and lead to health problems. In the present study, disposable face masks, the use of which has increased due to the Covid-19 pandemic throughout the world and which cause environmental pollution, were divided into very small pieces and utilized as a modifier in the bitumen binder. Therefore, this study aimed to provide a solution to such a significant environmental problem. Five different ratios of waste mask and the single ratio of styrene–butadienestyrene (SBS) were added to the pure binder and the rheological, physical, and chemical properties of the modified binders were compared. The result showed that adding a waste mask and SBS to the pure bitumen caused increases in binders’ softening point and viscosity and reductions in the penetration value. Waste mask modifications were able to better maintain its elastic properties both at low stress and high-stress levels with increasing temperature. 3% SBS was the binder most affected by temperature rise. As a result, it has been determined that binders containing more than 2% waste mask have better performance characteristics than binders containing 3% SBS in terms of physical and rheological properties.

Multilayer biodegradable films with a degradation initiation function triggered by weakly alkaline seawater

A non-biodegradable polymer (cellulose triacetate; CTA) was coated on the surface of a biodegradable polymer film (poly(3-hydroxybutylate-co-3-hydroxyhexanoate); PHBH), and the multilayer coated films were characterized using microscopy and spectroscopic techniques. The enzymatic degradability of the CTA-coated PHBH films was compared with that of non-coated PHBH films in the presence of an enzyme mixture (cellulase and PHB depolymerase). Non-coated PHBH films were effectively degraded; however, the CTA-coated films were only slightly degraded, indicating that the CTA coating could suppress PHBH biodegradation during use. Surface-deacetylated coated films (with a degree of substitution of 1.3) could be degraded by the same enzyme mixture, indicating that the deacetylation of CTA in an alkaline environment can trigger the degradation of PHBH. Furthermore, degradation tests in seawater demonstrated that CTA was deacetylated under weakly alkaline seawater conditions, and the degradation of cellulose acetate on the surface exposed the PHBH underneath, thereby allowing PHBH degradation. Overall, the results suggest that CTA coatings can effectively serve to initiate the biodegradation of PHBH when released into the ocean.

Effect of Melt Jet Spinning Process on Poly(lactic acid) Disposable Nonwoven Fabric Production

In the light of marine microplastic pollution and mounting environmental degradation, this research proposes biodegradable poly(lactic acid) (PLA) nonwoven fabric produced by novel melt jet spinning technology under various process conditions. In the study, the die temperature was varied at 210, 230, and 250 °C and the die-to-collector distance was varied between 30, 60, 90, and 120 cm. The performance metrics included fiber diameter, fiber crystallinity, fabric weight, air permeability, and contact angle. The results revealed that the optimal die temperature was 250 °C. At 250 °C, the fibers were of fine size with high crystallinity, independent of collector distances. Specifically, the die-to-collector distance, given the optimal die temperature, had negligible effect on the fiber diameter and crystallinity. On the other hand, the collector distance played a role in the nonwoven fabric characteristics. The collector distance was positively correlated with the elongation at break and air permeability but inversely correlated with the fabric density and tensile strength. The fabric contact angles were found to be in the range of 124–130 °, indicating the hydrophobicity of PLA nonwoven fabric. Essentially, the novelty of this research lies in the use of biodegradable PLA polymers, as opposed to conventional petroleum-based non-biodegradable polymers; and melt jet spinning technology to realize fine microfibers (1–10 µm).

Face Masks to Combat Coronavirus (COVID-19)-Processing, Roles, Requirements, Efficacy, Risk and Sustainability.

Increasingly prevalent respiratory infectious diseases (e.g., COVID-19) have posed severe threats to public health. Viruses including coronavirus, influenza, and so on can cause respiratory infections. A pandemic may potentially emerge owing to the worldwide spread of the virus through persistent human-to-human transmission. However, transmission pathways may vary; respiratory droplets or airborne virus-carrying particles can have a key role in transmitting infections to humans. In conjunction with social distancing, hand cleanliness, and other preventative measures, the use of face masks is considered to be another scientific approach to combat ubiquitous coronavirus. Different types of face masks are produced using a range of materials (e.g., polypropylene, polyacrylonitrile, polycarbonate, polyurethane, polystyrene, polyester and polyethylene) and manufacturing techniques (woven, knitted, and non-woven) that provide different levels of protection to the users. However, the efficacy and proper disposal/management of the used face masks, particularly the ones made of non-biodegradable polymers, pose great environmental concerns. This review compiles the recent advancements of face masks, covering their requirements, materials and techniques used, efficacy, challenges, risks, and sustainability towards further enhancement of the quality and performance of face masks.

Electrospun Nanofibers Revisited: An Update on the Emerging Applications in Nanomedicine.

Electrospinning (ES) has become a straightforward and customizable drug delivery technique for fabricating drug-loaded nanofibers (NFs) using various biodegradable and non-biodegradable polymers. One of NF’s pros is to provide a controlled drug release through managing the NF structure by changing the spinneret type and nature of the used polymer. Electrospun NFs are employed as implants in several applications including, cancer therapy, microbial infections, and regenerative medicine. These implants facilitate a unique local delivery of chemotherapy because of their high loading capability, wide surface area, and cost-effectiveness. Multi-drug combination, magnetic, thermal, and gene therapies are promising strategies for improving chemotherapeutic efficiency. In addition, implants are recognized as an effective antimicrobial drug delivery system overriding drawbacks of traditional antibiotic administration routes such as their bioavailability and dosage levels. Recently, a sophisticated strategy has emerged for wound healing by producing biomimetic nanofibrous materials with clinically relevant properties and desirable loading capability with regenerative agents. Electrospun NFs have proposed unique solutions, including pelvic organ prolapse treatment, viable alternatives to surgical operations, and dental tissue regeneration. Conventional ES setups include difficult-assembled mega-sized equipment producing bulky matrices with inadequate stability and storage. Lately, there has become an increasing need for portable ES devices using completely available off-shelf materials to yield highly-efficient NFs for dressing wounds and rapid hemostasis. This review covers recent updates on electrospun NFs in nanomedicine applications. ES of biopolymers and drugs is discussed regarding their current scope and future outlook.

Measurement of microplastic settling velocities and implications for residence times in thermally stratified lakes

AbstractMicroplastics residence times in lakes are currently poorly understood. In this work, settling experiments with pristine and biofilm‐colonized microplastic particles were combined with model calculations to evaluate settling velocities, particle distributions, and residence times in the epilimnion, metalimnion, and hypolimnion of a hypothetical stratified lake broadly based on Upper Lake Constance. Settling velocities of various biodegradable and nonbiodegradable polymers of various shapes, sizes, and biofilm colonization were measured in a settling column. The settling velocities ranged between ~ 0.30 and ~ 50 mm s−1. Particle sizes and polymer densities were identified as primary controls on settling rates. Microplastic particles that had been exposed to a lake environment for up to 30 weeks were colonized by a range of biofilms and associated extracellular polymeric substances; surprisingly, however, the settling velocity did not vary significantly between pristine and colonized microplastic particles. Simulated microplastic residence times in the model lake varied over a wide range of time scales (10−1 to 105 d) and depended mainly on the size of the particles and depth of the lake layer. Long residence times on the order of 105 d (for 1‐μm microplastic particles) imply that for small microplastic particles there is a high probability that they will be taken up at some stage by lake organisms. As the lake retention time (~ 4.5 years) is considerably shorter than the residence time of small microplastics, negligible quantities of these microplastic particles should be found in the lake sediment unless some other process increases their settling velocity.

A Review of Nonbiodegradable and Biodegradable Composites for Food Packaging Application

The dependency on nonbiodegradable-based food packaging, increase in population growth, and persistent environmental problems are some of the driving forces in considering the development of biodegradable food packaging. This effort of green packaging has the potential to solve issues on plastic wastes through the combination of biodegradable composite-based food packaging with plant extracts, nanomaterials, or other types of polymer. Modified biodegradable materials have provided numerous alternatives for producing green packaging with mechanical strength, thermal stability, and barrier performance that are comparable to the conventional food packaging. To the best of our knowledge, the performance of nonbiodegradable and biodegradable composites as food packaging in terms of the above properties has not yet been reviewed. In this context, the capability of biodegradable polymers to substitute the nonbiodegradable polymers was emphasized to enhance the packaging biodegradation while retaining the mechanical strength, thermal stability, barrier properties, and antioxidant and antimicrobial or antibacterial activity. These are the ultimate goal in the food industry. This review will impart useful information on the properties of food packaging developed from different polymers and future outlook toward the development of green food packaging.

Can polymer-degrading microorganisms solve the bottleneck of plastics’ environmental challenges?

Increasing world population and industrial activities have enhanced anthropogenic pollution, plastic pollution being especially alarming. So, plastics should be recycled and/or make them biodegradable. Chemical and physical remediating methods are usually energy consuming and costly. In addition, they are not ecofriendly and usually produce toxic byproducts. Bioremediation is a proper option as it is cost-efficient and environmentally friendly. Plastic production and consumption are increasing daily, and, as a consequence, more microorganisms are exposed to these nonbiodegradable polymers. Therefore, investigating new efficient microorganisms and increasing the knowledge about their biology can pave the way for efficient and feasible plastic bioremediation processes. In this sense, omics, systems biology and bioinformatics are three important fields to analyze the biodegradation pathways in microorganisms. Based on the above-mentioned technologies, researchers can engineer microorganisms with specific desired properties to make bioremediation more efficient.

Specific labelling of phagosome-derived vesicles in macrophages with a membrane dye delivered with microfabricated microparticles

Phagocytosis performed by a macrophage involves complex membrane trafficking and reorganization among various membranous cellular structures including phagosomes and vesicles derived from the phagosomes known as phagosome-derived vesicles. The present work reports on development of a technique that allows to specifically label the phagosome-derived vesicles in macrophages with a membrane dye. The technique is based on the use of microfabricated microparticles that are made of a thermosensitive nonbiodegradable polymer poly(N-isopropylacrylamide) (PNIPAM) or its derivative and contain a membrane dye 1,1′-dialkyl-3,3,3′,3′-tetramethylindodicarbocyanine (DiI). The microparticles can be phagocytosed by RAW264.7 macrophages into their phagosomes, resulting in formation of intracellular DiI-positive vesicles derived from the phagosomes. The DiI-positive vesicles are motile and acidic; can be stained by fluorescently labelled dextran added in the culture medium; and can accumulate around new phagosomes, indicating that they possess properties of lysosomes. This technique is also applicable to another membrane dye 3,3′-dioctadecyloxacarbocyanine (DiO) and holds great potential to be useful for advancing our understanding of phagocytosis. Statement of significancePhagocytosis performed by macrophages is a cellular process of great importance to various applications of biomaterials such as drug delivery and medical implantation. This work reports on a technique for characterizing phagocytosis based on the use of poly(N-isopropylacrylamide), which is a major biomaterial with numerous applications. This technique is the first of its kind and has generated an original finding about phagocytosis. In addition to drug delivery and medical implantation, phagocytosis plays critical roles in diseases, injuries and vaccination. This work could thus attract immediate and widespread interests in the field of biomaterials science and engineering.

Emerging uses of PLA-PEG copolymer in cancer drug delivery.

Traditional therapies need high systematic dosages that not only destroys cancerous cells but also healthy cells. To overcome this problem recent advancement in nanotechnology specifically in nanomaterials has been extensively done for various biological applications, such as targeted drug delivery. Nanotechnology, as a frontier science, has the potential to break down all the obstacles to be more effective and secure drug delivery system. It is possible to develop nanopolymer based drug carrier that can target drugs with extreme accuracy. Polymers can advance drug delivery technologies by allowing controlled release of therapeutic drugs in stable amounts over long duration of time. For controlled drug delivery, biodegradable synthetic polymers have various benefits over non-biodegradable polymers. Biodegradable polymer either are less toxic or non-toxic. Polylactic Acid (PLA) is one of the most remarkable amphipathic polymers which make it one of the most suitable materials for polymeric micelles. Amphiphilic nanomaterial, such as Polyethylene Glycol (PEG), is one of the most promising carrier for tumor targeting. PLA-PEG as a copolymer has been generally utilized as drug delivery system for the various types of cancer. Chemotherapeutic drugs are stacked into PLA-PEG copolymer and as a result their duration time delays, hence medications arrive at specific tumor site.

Nonpolar Graphene Quantum Dot-Based Hydrophobic Coating from Microwave-Assisted Treatment of Styrofoam Waste

Graphene quantum dots (GQDs), one of the most promising nanoforms of carbon, have shown exceptional physiochemical properties owing to their strong three-dimensional quantum confinement. By altering the band gap or edge functionalization in GQDs, the properties can be tuned to meet challenging demands of modern computational and quantum devices. GQDs have primarily been synthesized at the lab scale so far, by both top-down and bottom-up approaches, using various natural or synthetic carbon-rich precursors. Only a few milligrams of the precursor is typically used in the synthesis, and it also involves hazardous acids, bases, or other catalysts, which impose additional time, labor, and cost for their removal. GQDs made hitherto are also functionalized with polar moieties due to the use of acids or bases in the synthesis, resulting in insolubility of GQDs in nonpolar solvents. Herein, an acid/base-free, microwave-assisted pyrolytic process is developed where GQDs of controlled size without any polar functionalities are synthesized using Styrofoam waste as the precursor. The structure of GQDs is confirmed by transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and other spectroscopic analysis, and it is found to be single layered with an average size of 5.5 ± 1.5 nm. A maximum yield of 15% is obtained by optimizing the pyrolysis temperature and exposure time of the precursor, and GQDs are found to be highly soluble in nonpolar solvents, including toluene and cyclohexane. The obtained GQDs were used as a promising agent to provide durable hydrophobicity and excellent self-cleaning property when coated on cotton fabric. The use of nonbiodegradable polymer waste such as Styrofoam to generate nonpolar GQDs of controlled dimensions provided a complete solution to not only curb deleterious effects of polymeric waste but also enable production of high value-added products for vast applications.

Risk for the release of an enormous amount of nanoplastics and microplastics from partially biodegradable polymer blends

Non-biodegradable polymers are released as microplastics into the environments during the biodegradation of partially biodegradable polymer blends.

Polybutylene succinate, a potential bio-degradable polymer: synthesis, copolymerization and bio-degradation

Biodegradable polymers are advantageous over non-biodegradable polymers in terms of degradation. Fabrication of bio-based polymers to mimic petroleum-based polymers, is believed to be an effective way to overcome the white pollution.

Lactic Acid-Sustainable Raw Material for Biodegradable Hot Melt Adhesive: Review

Currently, due to scarcity of hydrocarbon resources and the extensive use of water based, solvent based and hot melt adhesives in wood bonding in furniture industries and packaging industries that demand recyclability, compostability and bio-degradability, recently attention has been concentrated to making these formulations completely bio-based, sustainable and biodegradable. Biodegradable hot melt adhesives (HMAs) prepared from natural sources have a potential for use in furniture and packaging industries because of an increase in awareness of environmental issues, the replacement of conventional petroleum-derived hydrocarbon raw materials by renewable, biodegradable and sustainable materials has developed. In terms of environmental issues, such as climate crisis due to an increase of carbon dioxide emission, attempts have been made to produce HMAs using non-hydrocarbon resins, such as polylactic acid (PLA)-based resins, containing no petroleum as a raw material. Polylactic acid was prepared by self-condensation reactions of lactic acid or by lactide ring opening polymerisation, and used for packaging materials, sanitary pads, diapers etc., especially adhesives owing to its excellent processability and the excellent mechanical properties of its HMAs products. Therefore, recently the use of PLA materials as a substitute for non-biodegradable hydrocarbon-based polymers can be considered to be environmentally favourable. Here, we discussed the various uses of PLA as a sustainable and bio-degradable and sustainable hot melt adhesive.

Fabrication of biodegradable facemask layer using polylactic acid: Effect of flowrate on fiber forming properties

The research on biodegradable polymers for facemask applications is on full swing to reduce the environmental impacts caused due to the nonbiodegradable petroleum-based polymers. Polylactic acid (PLA) is one of the most famous biodegradable polymers, hence fabricating facemask using polylactic acid through electrospinning could provide an effective solution. Among various parameters of electrospinning, flow rate plays a significant role in fiber forming properties of electrospun nanofiber. In this study, the influence of varying flow rate on fiber forming properties were investigated in order to determine the optimum parameters to fabricate uniform PLA nanofibers. The nanofibers produced were characterized for fiber diameter, thickness and surface morphology and were compared with the commercial facemask. It was found that the flow rate of 1.5 mL/h provides uniform fiber diameter, thickness and surface morphology which can provide better protection similar to that of a commercial facemask.

Value-added products from waste plastics using dissolution technique

Non-biodegradable plastics polymers, such as low-density polyethylene (LDPE), polystyrene (PS), and polyvinyl chloride (PVC) are non-biodegradable and release toxic gases into the environment on combustion and after long use. This study includes the screening of a series of organic solvents for solubility parameters of LDPE and PS. The karanja biodiesel is also used as one of the solvents for the dissolution of plastics. In order to decide the best solvent to be used for the dissolution of plastic polymer, rate of dissolution, safety aspect, and cost of the solvent were considered. The solubility factor of LDPE and PS is found to be much closed to acetone, chlorobenzene, and karanja biodiesel. Out of them, karanja biodiesel is considered due to its environment friendly behavior. The output of the study is with three value-added products as high heating value fuel, good composite for low-density cement, and an oil-adsorbent. The dissolution products obtained are chemically analyzed using FTIR and GC–MS techniques to elucidate their composition. The BET and TGA techniques are used for physical analysis, viz., the porosity and thermal stability of the products respectively. The findings of dissolution methods in this article are compared with the conventional pyrolysis techniques for these plastics treatment.

Comparative polymer biodegradation efficiency of an isolated Acinetobacter sp. with Bravibacillus sp. and E. coli by resting cells

At a concentration of 4 g/L, an enteric polymer is utilized to target drug release in the small intestine and causes considerable toxicity in cells. Our ecology and ecosystem are also harmed by their non-biodegradable qualities. We isolated and identified polymer-degrading bacteria from industrial effluent in this work. The isolated strain's morphological, biochemical, and antibiotic sensitivities were also examined. The isolated strain was found to be gram-negative, round-shaped, and non-motile in morphological tests, while biochemical tests revealed it to be negative in starch agar and TSI but positive in methyl red, mannitol salt, Simmon citrate, urea agar, and catalase test. The isolated strain was highly resistant to ciprofloxacin and vancomycin. The isolated bacterium was identified as Acinetobacter sp. by 16S rRNA sequencing. Additionally, Acinetobacter sp. strains of Escherichia coli and Brevibacillus sp. were used separately to observe the degradation of five synthesized non-biodegradable polymers (maleic acid propane-1,2 diol glycerol co-polyester, maleic acid phthalic acid propane-1,2 diol glycerol co-polyester, maleic acid phthalic acid butan-1,4 diol glycerol co-polyester, phthalic acid succinic acid propane-1,2 diol glycerol co-polyester, and phthalic acid succinic acid buten-1,4 diol glycerol co-polyester. The capacity of all three strains to degrade the above-mentioned polymers was greater than 75%. E. coli, for example, had a rapid disintegration rate but was responsible for human gastrointestinal and urinary tract infections. As a result, our isolated Acinetobacter sp. can be employed to degrade synthetic polymers.

Synthesis and Characterization of Banana and Pineapple Reinforced Hybrid Polymer Composite for Reducing Environmental Pollution.

Nonbiodegradable polymers constitute major pollution and their usage cannot be ignored due to their properties. Hybrid polymer composite research has increased in recent times due to improved characteristics and biodegradable nature. The effect of different stacking sequences containing pineapple/banana/basalt fiber has been studied in the present work to reduce the usage of synthetic fibers without compromising on properties. Hybrid composites were manufactured using the hand layup method and were assessed for mechanical and morphological characteristics. The results showed that several properties improved by keeping the pineapple layer in the skin layer. The adhesion between the matrix and the fiber played a vital role in determining the properties of the composites manufactured. Morphological studies have concluded that the proper bonding between the matrix and the fiber has enhanced several properties.