ResearchSpace :: Browsing by Author "Muniyasamy, Sudhakar"

Browsing by Author "Muniyasamy, Sudhakar"

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Algae infused enhancement of PBAT stiffness: Investigating the influence of algae content on mechanical and thermal properties
(2024) Letwaba, J; Motloung, Mpho P; Muniyasamy, Sudhakar; Mavhungu, L; Mbaya, R; Okpuwhara, R
This study investigates the impact of algae loading on the properties of PBAT/algae bio-composites produced through a melt extrusion process. The integration of algae as a filler demonstrated a reinforcing effect on the PBAT matrix,leading to an increase in modulus with higher algae loading. Concurrently, the tensile strength and maximum tensile strain of PBAT decreased with an increase in algae content. The thermal stability of PBAT was affected by adding algae, resulting in bio-composites exhibiting an intermediate behavior compared with their neat precursors. The optimal formulation is achieved with 20 wt.% of algae incorporated into the PBAT matrix. The produced PBAT/algae bio-composites, demonstrated versatile applications across a wide range of products.
Benchmarking bioplastics: A natural step towards a sustainable future
(Springer, 2020-08) Bhagwat, G; Gray, K; Wilson, SP; Muniyasamy, Sudhakar; Vincent, SGT; Bush, R; Palanisam, T
The ubiquitous presence of plastic litter and its tending fate as marine debris have given rise to a strong anti-waste global movement which implicitly endorses bioplastics as a promising substitute. With ‘corporate social responsibility’ growing evermore popular as a business promotional tool, companies and businesses are continually making claims about their products being “green”, “environmentally friendly”, “biodegradable”, or “100% compostable”. Imprudent use of these words creates a false sense of assurance at the consumer end about them being responsible towards the environment by choosing these products. The policies surrounding bioplastics regulation are neither stringent not enforceable at both national and international stage which indirectly allow these “safe words” to be used as an easy plug to validate the supposed corporate social responsibility. Similar to conventional plastics, unregulated and mismanaged bioplastics could potentially create another environmental mayhem. Therefore, it is a crucial time to harness the power of law to set applicable standards with a high threshold for the classification of “bioplastics”, which companies can aspire to, and customers can trust. In this review, we analyse the multifarious international bioplastics standards, critically assess the potential shortcomings and highlight how the intersection of law with science and technology is crucial towards the reform of bioplastics regulation.
Bio-synthesis of silver nanoparticles using agroforestry residue and their catalytic degradation for sustainable waste management
(Springer Verlag, 2017-07) Anand, K; Kaviyarasu, K; Muniyasamy, Sudhakar; Roopan, SM; Gengan, RM; Chuturgoon, AA
The sustainable synthesis of nanoparticles provides an eco-friendly and interesting approach in the domain of clean synthesis and nanobiotechnology. The in vitro synthesis of silver nanoparticles from the aqueous extract of an indigenous South African plant: Ekebergia capensis is reported in this paper. The rapid fabrication of Ag NPs were observed by visual colour and was confirmed using UV spectroscopy; the emergence of a yellow–brownish colour confirmed the yield of silver nanoparticles. Also, a time course study on the effect of concentration of AgNO3 was undertaken. The synthesized Ag NPs was characterized by TEM, XRD, and DLS whilst, FTIR and GC–MS provided information on the functional groups adhered to the surface of the Ag NPs. The XRD peak of synthesized Ag NPs showed their crystalline structure. DLS and TEM studies revealed spherical or near spherically shaped Ag NPs of particle size 20–120 nm. Furthermore, the catalytic performance of Ag NPs in the degradation of Allura red (AR) and Congo red (CR) were characterised by UV spectrophotometry. The Silver nanoparticles were observed to have excellent catalytic properties on the degradation of AR and CR which is confirmed by the dyes mineralized in λmax values. The catalytic process involved the electrons relay effect and is attributed with time.
Biobased Biodegradable Polybutylene Succinate Polymers and Composites: Synthesis, Structure Properties and Applications—A Review
(2025) Makgwane, Peter R; Muniyasamy, Sudhakar; Hlekelele, Lerato; Swanepoel, Andri; Sypu, Venkata S; Mdlalose, Lindani M; Naidoo, Saloshee; Cele, Zamani; Maity, Arjun; Balogun, Mohammed O; Botlhoko, OJ
The materialization of polybutylene succinate (PBS) belongs to the family of polyesters which are degradable and biodegradable, their biodegradability properties have attracted enormous interest for product development towards different polymer-based applications. Besides its biodegradability, PBS can be derived from petroleum and biobased monomers. At the same time, the latter is the driving factor for its growing interest in bioplastics for fully green and sustainable biobased-derived polymer products. The processes and techniques presented herein, are based on the production of biobased succinic acid monomer to PBS. However, the counterpart biobased monomer 1,4-butanediol (1,4-BDO) production has not been commercially demonstrated. This review discusses the progress in state-of-the-art developments in the synthesis strategies of PBS, its copolymers, and composites with the view to improve molecular weight, thermal, and mechanical properties. It further analyzes the different strategies to synthesize modified PBS polymer composites from organic and inorganic nanofillers to enhance their chemical, thermal, stability and mechanical structural properties. Importantly, the review highlights the progress in the applications of PBS copolymers and composites with tailored structure-designed properties for specific sectors such as packaging films, biomedical and drug release, fire retardants, and agricultural products. The structure-functional performance characteristics of these developments in the PBS, copolymers, and composites are highlighted to provide baseline insights for future developments in engineering the specific applications, and structural interface PBS composites with enhanced structure-functional performance properties.
Biobased biodegradable polymers for ecological applications: A move towards manufacturing sustainable biodegradable plastic products
(Wiley, 2019-03) Muniyasamy, Sudhakar; Mohanrasu, K; Gada, Abongile; Mokhena, Teboho C; Mtibe, A; Boobalan, T; Paul, V; Arun, A
In recent years, the emerging environmental concern for traditional plastic materials has posed a challenge to academia and industries to come up with an alternative eco-friendly material. This is because the post-consumer plastic items are non-biodegradable when disposed in natural environments such as landfill and marine sites. However, these plastics accumulate in these natural environments and create serious pollution that persists to cause environmental damage for decades. In order to address these issues, an innovative global circular economic concept in manufacturing new sustainable green products is currently underway to develop sustainable bioplastic products that will have economic, environment and social benefits. In this chapter the development of biopolymers directly extracted from biomass, monomer production from fermentation and microbial synthesis of biopolymer and their current.
Biodegradability of biobased polymeric materials in natural environments: Structures and Chemistry
(Scrivener Publishing LLC, 2017-03) Muniyasamy, Sudhakar; John, Maya J
The development of biobased polymer materials from renewable resources meets the concept of sustainability, offering the potential of renewability, biodegradation, and a path away from the problems associated with plastic derived from nonrenewable sources. As the biomaterials interest grows, the ecological impact of these postconsumer polymer products, when they enter into waste streams (landfill, compost, marine water, and sewage), does not contribute negatively toward the environment. The ultimate fate of biodegradable polymeric materials is focused on their conversion by microorganisms into final elemental products such as carbon dioxide, water, and new microbial biomass (i.e., mineralization). In this chapter, the necessary conditions for biodegradability of polymers, as well as the involved physical, chemical, and biological mechanisms, are reviewed. Various analytical techniques and standard test methods for evaluating the potential biodegradability and its toxicity level of polymeric materials in different environments are discussed in accordance with international standards and regulations.
Biodegradable behaviour of waste wool and their recycled polyster preforms in aqueous and soil conditions
(2021-01) Muniyasamy, Sudhakar; Patnaik, Asis
Present study deals with the biodegradable behavior of individual components and their preforms of nonwoven biocomposites developed from waste wool fibers including coring wool (CW), dorper wool (DW) and recycled polyester fibers (RPET). A respirometric technique was employed to estimate the production of CO2 during the biodegradation experiments under soil and aqueous media conditions. Functional groups of test samples before and after biodegradation were analyzed using Fourier transform infrared spectroscopy (FTIR). Leaching chemicals such as formaldehyde (hydrolyzed) and Chromium VI (Cr VI) was also measured. The CO2 emission in wool fibers CW and DW indicated 90% and 60% biodegradation in soil burial and aqueous media conditions respectively, for 100 days incubation. RPET fibers, 20% and 10% biodegradation in soil burial and aqueous media conditions was measured respectively while the preforms of waste wool and RPET reflected 30% and 25% biodegradation in soil burial and aqueous media conditions, respectively. The degradation of end functional groups such as carbonyl (keto and ester), aldehyde and hydroxyl were also confirmed by FTIR. The DW and CW wool fibers showed higher Cr(VI) concentration as compared to the RPET. The released formaldehyde results showed higher concentration for RPET preforms as compared to waste wool preforms. These results suggest that waste wool preforms are extremely environment friendly as compared to RPET preforms. Thus, waste wool preforms it can be potentially utilized for preparing biocomposite materials and associated biobased products.
Biodiesel production from Ulva linza, Ulva tubulosa, Ulva fasciata, Ulva rigida, Ulva reticulate by using Mn2ZnO4 heterogenous nanocatalysts
(Elsevier, 2019-11) Sivaprakasha, G; Kohanrasua, M; Ananthia, V; Jothibasu, M; Duc Nguyend, D; Ravindran, B; Chang, SW; Nguyen-Tri, P; Tran, N; Muniyasamy, Sudhakar
Seaweeds are found abundance in most seashores. They contain relatively high lipid contents and are exhibiting medicinal properties. The present work focused on the use of seaweed species Ulva linza, U. tubulosa, U. fasciata, U. rigida, and U. reticulate to synthesize Mn2ZnO4 composite nanoparticles. The later was utilized for biodiesel production and its antibacterial potential was also assessed. Heterogeneous mixed metal oxides are suitable catalysts for biodiesel production due to ease of separation, reusability and environmental friendliness. The employment of multi-resistant organisms (MROS) is of major importance in modern medicines. Thus there is an extreme need for potential antibacterial alternatives such as metal oxides. Mn2ZnO4 nanoparticles were synthesized by using a co-precipitation method. The crystalline behavior and morphological characterizations were carried out through XRD, FE-SEM, Raman Spectra and FT-IR respectively. The particle size was found to be 42 nm. Fatty Acid Methyl Ester (FAME) produced from Ulva species was analyzed by gas chromatography and physical parameters were also determined. The yields were as follows: U. linza 72.3%, U. tubulosa 72%, U. fasciata 70.6%, U. rigida 70.4%, and U. reticulate 71.5%. The antibacterial potential of synthesized Mn2ZnO4 nanoparticles after transesterification, showed strong antibacterial activity against both gram positive and gram negative bacteria and were found to be comparable to commercially available antibiotics. To assess their antibacterial efficiency, the minimum inhibition concentration was measured. The used catalysts exhibit high efficient catalytic activity on degrading methylene blue under UV irradiation.
Bioelectricity generation by natural microflora of septic tank wastewater (STWW) and biodegradation of persistent petrogenic pollutants by basidiomycetes fungi: An integrated microbial fuel cell system
(2021-01) Thulasinathan, B; Jayabalan, T; Sethupathi, M; Kim, W; Muniyasamy, Sudhakar; Sengottuvelan, N; Nainamohamed, S; Ponnuchamy, K; Alagarsamy, A
The microbial fuel cell is a unique advantageous technology for the scientific community with the simultaneous generation of green energy along with bioelectroremediation of persistent hazardous materials. In this work, a novel approach of integrated system with bioelectricity generation from septic tank wastewater by native microflora in the anode chamber, while Psathyrella candolleana with higher ligninolytic enzyme activity was employed at cathode chamber for the biodegradation of polycyclic aromatic hydrocarbons (PAHs). Six MFC systems designated as MFC1, MFC2, MFC3, MFC4, MFC5, and MFC6 were experimented with different conditions. MFC1 system using natural microflora of STWW (100%) at anode chamber and K3[Fe(CN)6] as cathode buffer showed a power density and current density of 110 ± 10 mW/m2 and 90 ± 10 mA/m2 respectively. In the other five MFC systems 100% STWW was used at the anode and basidiomycetes fungi in the presence or absence of individual PAHs (naphthalene, acenaphthene, fluorene, and anthracene) at the cathode. MFC2, MFC3, MFC4, MFC5, and MFC6 had showed power density of 132 ± 17 mW/m2, 138 ± 20 mW/m2, 139 ± 25 mW/m2, and 147 ± 10 mW/m2 respectively. MFC2, MFC3, MFC4, MFC5, and MFC6 had showed current density of 497 ± 17 mA/m2, 519 ± 10 mA/m2, 522 ± 21 mA/m2 and 525 ± 20 mA/m2 respectively. In all the MFC systems, the electrochemical activity of anode biofilm was evaluated by cyclic voltammetry analysis and biofilms on all the MFC systems electrode surface were visualized by confocal laser scanning microscope. Biodegradation of PAHs during MFC experimentations in the cathode chamber was estimated by UV-Vis spectrophotometer. Overall, MFC6 system achieved maximum power density production of 525 ± 20 mA/m2 with 77% of chemical oxygen demand removal and 54% of coulombic efficiency at the anode chamber and higher anthracene biodegradation (62 ± 1.13%) at the cathode chamber by the selected Psathyrella candolleana at 14th day. The present natural microflora - basidiomycetes fungal coupled MFC system offers excellent opening towards the simultaneous generation of green electricity and PAHs bioelectroremediation.
Bioplastics: From the landfill to the market
(Nova Publishers, 2018-03) Muniyasamy, Sudhakar; Ofosu, Osei; Linganiso, LZ; Motaung, TE
The present chapter is focused on the development of environmentally friendly materials (biodegradable plastics) from recycled petroleum based plastics. Petroleum based plastics are collected from the landfill sites, washes, separated and subjected to a cutter for size reduction. After this, a hot melt extrusion is used to mix them with additives extracted from agricultural residues such as sugarcane bagasse or maize stalk to induce biodegradation. Environmentally biodegradable materials are promising green materials as they degrade at landfill in less than a year. However, it is necessary to address the enviornmental biodegradability of environmentally friendly materials in order to meet various commercial and environmental needs for their sustainable growth. In this chapter, we discussed recycling of petroleum based plastics from the landfill sites and conversion to environmentally friendly plastics. Applications of sustainable materials are also discussed.
Design of 3D printable boehmite alumina/thermally exfoliated reduced graphene oxide-based polymeric nanocomposites with high dielectric constant, mechanical and thermomechanical performance
(2024-09) Botlhoko, Orebotse J; Makwakwa, Dimakatso M; Muniyasamy, Sudhakar
In this study, melt-blending was employed to blend 80 wt% poly(lactic acid) and 20 wt% poly(ε-caprolactone) (80 %PLA/20 %PCL) with boehmite alumina-thermally exfoliated reduced graphene oxide (BA-TERGO) as nanofillers. Herein, we present a novel synergy effect of BA/TERGO particles on improving the dielectric constant while maintaining dielectric loss at lower magnitudes. Also, improving the thermomechanical properties of tough PLA/PCL nanocomposite through the incorporation of a dual-filer system strategy. Consequently, remarkable increase in dielectric constant was achieved for BA-TERGO/blend nanocomposite. In particular, the blend exhibited dielectric constant of about 2.91, while the BA-TERGO/blend nanocomposite exhibited dielectric constant of about 4.93 at a frequency of 2.0 ×106 Hz and a temperature of 190 ºC. On the other hand, tensile modulus of the BA-TERGO/blend nanocomposite increased from 1908.5 MPa to 2505.2 MPa and the tensile strength increased from 70.48 MPa to 96.3 MPa when compared to that of the neat blend. BA-blend and BA-TERGO/blend nanocomposites provided the improved storage modulus and thermal stability. This finding renders PLA-based biodegradable materials suitable for tough 3D printable material with potential for integrated circuits applications.
Development of sustainable biobased polymer and bio-nanocomposite materials using nanocellulose obtained from agricultural biomass
(Routledge, 2020-07) Mtibe, Asanda; Muniyasamy, Sudhakar; Motaung, TE; Godfrey, Linda K; Görgens, JF; Roman, H
Biobased polymer and bio-nanocomposites have provided significant improvement in material science, moving towards the development of green materials to replace petro-based materials. The present study investigated the value-added utilisation of agriculturalbiomass residues derived from sugar cane bagasse and maize stalks for the development of biobased polymer and bio-nanocomposite materials for specific applications. In this study, extraction of cellulose and nanocellulose of environmentally friendly polymeric materials and their composite peoducts were studied. The study showed that the incorporation of nanocellulose into biopolymer matrix could produce bio-nanocomposites for specific uses in various applications, mainly in the biomedical and green packaging sectors.
Evaluation of mechanical properties of calotropis giganteastem fiber-rein forced composite material
(2016-12) Aruna, M; Muniyasamy, Sudhakar
The awareness in natural fiber reinforced composite materials is rapidly growing both in terms of industrial applications and fundamental research. Natural fibers have recently become attractive to researchers, engineers and scientists as an alternative reinforcement for fiber reinforced polymer (FRP) composites. Owing to their availability, low cost, good mechanical properties, high specific strength, non-abrasive, eco-friendly and bio-degradability characteristics, they are exploited as a replacement for the conventional fiber, such as aramid and carbon. Several chemical modifications are employed to improve the interfacial matrix-fiber bonding resulting in the enhancement of mechanical properties of the composites. Calotropisgigenteais a species of calotropis, native to Cambodia, Indonesia, Malaysia, Philippines, Thailand, Sri Lanka, India, China, Pakistan, Nepal, and tropical Africa. Itsfiber was extracted manually from the plant’s stem and treated chemically. The samples have been prepared by varying the fiber percentages and epoxy resin. Hybrid Composites are fabricated using raw calotropisgigenteastem fiber/glass with varying fiber weight percent 5:0 to 5:3 weight by using hand layup method. The fabricated specimens were cut as rectangular pieces according to the ASTM standards for conducting all tests. The purpose of this paper is to assess the tensile strength, impact strength, density and hardness of hybrid calotropisgigantea stem fiber reinforced composites. Results illustrates that the use of less than 12 gm glass fiber in this composite increases tensile strength, impact, density and hardness.
Melt-extruded high-density polyethylene/pineapple leaf waste fiber composites for plastic product applications
(2024) Khumalo, MV; Sethupathi, M; Skosana, SJ; Muniyasamy, Sudhakar
This study examines the impact of Pineapple Leaf Fiber (PALF) loading on the properties of High-Density Polyethylene (HDPE)/PALF composites successfully produced through a melt extrusion process. The melt-extruded HDPE/PALF composites were characterized by their thermal and mechanical properties and their morphologies. Subsequently, adding 5% maleic anhydride (MA) to the HDPE/PALF composite formulation led to significant improvements in the mechanical strength properties. Moreover, adding 10 wt.% PALF and 5% MA to the composites improves the crystallinity (10.38%) and Young’s modulus (17.30%) properties and affects the thermal stability. The optimal formulation is achieved with 10 wt.% PALF filler incorporated into the HDPE composite. This study highlights the promising potential of HDPE/PALF composites for plastic product applications.
Optimization of media components and culture conditions for polyhydroxyalkanoates production by Bacillus megaterium
(2020-07) Mohanrasu, K; Guru Raj Rao, R; Dinesh, GH; Zhang, K; Siva Prakash, G; Song, D; Muniyasamy, Sudhakar; Pugazhendhi, A; Jeyakanthan, A; Arun, A
Polyhydroxybutyrate (PHB) accumulating Bacillus megaterium was isolated from marine water. To increase the PHB productivity by Bacillus megaterium, steps were taken to evaluate the effects of carbon sources (arabinose, glucose, glycerol, lactose, lactic acid, mannitol, sodium acetate, starch and sucrose at a level of 20 g/L), nitrogen sources (ammonium chloride, ammonium sulphate, glycine, potassium nitrate, protease peptone and urea at a level of 2 g/L) and different pH. A maximum yield of 2.74 g/L of PHB was achieved for glucose as the carbon source and ammonium sulphate as the nitrogen source at pH 7. The optimized conditions were further used for batch fermentation throughout 72 h. Significantly maximum PHB of 5.61 g/L was obtained in a laboratory scale bioreactor at 64 h. The extracted polymer was compared with the authentic PHB and was confirmed to be PHB using FTIR, 1H NMR, DSC and TGA analysis, respectively.
Recent developments of pineapple leaf fiber (PALF) utilization in the polymer composites—A review
(2024-08) Sethupathi, M; Khumalo, MV; Skosana, SJ; Muniyasamy, Sudhakar
Plant fibers’ wide availability and accessibility are the main causes of the growing interest in sustainable technologies. The two primary factors to consider while concentrating on composite materials are their low weight and highly specific features, as well as their environmental friendliness. Pineapple leaf fiber (PALF) stands out among natural fibers due to its rich cellulose content, cost-effectiveness, eco-friendliness, and good fiber strength. This review provides an intensive assessment of the surface treatment, extraction, characterization, modifications and progress, mechanical properties, and potential applications of PALF-based polymer composites. Classification of natural fibers, synthetic fibers, chemical composition, micro cellulose, nanocellulose, and cellulose-based polymer composite applications have been extensively reviewed and reported. Besides, the reviewed PALF can be extracted into natural fiber cellulose and lignin can be used as reinforcement for the development of polymer biocomposites with desirable properties. Furthermore, this review article is keen to study the biodegradation of natural fibers, lignocellulosic biopolymers, and biocomposites in soil and ocean environments. Through an evaluation of the existing literature, this review provides a detailed summary of PALF-based polymer composite material as suitable for various industrial applications, including energy generation, storage, conversion, and mulching films.
Recycling of plastics and composites materials and degradation technologies for bioplastics and biocomposites
(Woodhead Publishing, 2021-01) Muniyasamy, Sudhakar; Dada, OS; Nayak, R; Patnaik, A
Plastic becomes a necessity for our day-to-day life, since it has been widely used in all major sectors including the textile industry. However, the tackling of these recalcitrant plastic-based products wastes is becoming the most challenging part around the world contributing severe environmental pollution and greenhouse gas emission. Currently, the paradigm shifts from the use of conventional oil-based plastics to biobased plastics from renewable sources as a solution to environmental pollution and reduces carbon footprint. Biobased materials provide as a green alternative through the recycling of plastic wastes along with biogenic capitals that are available within our ecosystems across the globe. In this chapter, the biodegradation propensities, biodegradation technologies, and mechanisms of bioplastics and biocomposites were highlighted. Diverse certification systems to ensure environmental safety and sustainability of bioplastic and biocomposites in our environment were also presented. This chapter presents the potential and opportunities for manufacturing biobased plastics and biocomposites to offer considerable benefits in the circular economy concept and high environmental significance to replace conventional plastics.
Synthetic, natural derived lipid nanoparticles and polymeric nanoparticles drug delivery applications
(Springer, 2020-01) Mohanrasu, K; Siva Prakash, G; Boobalan, T; Ananthi, V; Dinesh, GH; Anand, K; Muniyasamy, Sudhakar; Chuturgoon, A; Arun, A; Krishnan, A; Chuturgoon, A
In modern therapeutic field, the delivery to the desired site is a crucial bottleneck that needs to be addressed for efficacy and potency of the administrated drug. The recent advancements in the field of nanotechnology has enabled researchers to deliver the drug and other diagnostic agents without unfavourabel effect in huma. Though drug delivery system (DDS) is highly advanatageous, the clinical success rate depends on the appropriate carrier molecules which precisely recognise the target site for the release of drug and its biocompatibility. To overcome this concern both synthetic and naturally derived liip-based nano carriers are the preeminent option as it is biocompatible, non-toxic, enhances the bioavailabity of poorly absorbed drugs, drug release modulation flexibility, improved drug loading capacity and stability.
The effect of mechanical recycling on the thermal, mechanical, and chemical properties of Poly (Butylene Adipate-Co-Terephthalate) (PBAT), Poly (Butylene Succinate) (PBS), Poly (Lactic Acid) (PLA), PBAT-PBS blend and PBAT-TPS biocomposite
(2024-01) Nomadolo, Elizabeth N; Mtibe, Asanda; Ofosu, Osei; Mekoa, Caroline V; Letwaba, Lesetja J; Muniyasamy, Sudhakar
Mechanical recycling of plastics is regarded as the best option to minimize plastic waste pollution in the environment as it is well established and ofers valorisation of plastics; however, there is limited research on the mechanical recyclability of biopolymers. This work aimed to evaluate the efect of multiple reprocessing on the mechanical, thermal, physical, chemical, and morphological properties of poly (butylene adipate-co-terephthalate) (PBAT), poly (butylene succinate) (PBS), poly (lactic acid) (PLA), PBAT-PBS blend, and PBAT-thermoplastic starch (TPS) composite. Low-density polyethylene (LDPE), a conventional non-biodegradable plastic, was also reprocessed for comparison studies. The biopolymers were extruded seven times in a twin-screw extruder and injection moulded into test specimens. Their properties were investigated at each extrusion cycle. Tensile, impact strength, and melt fow index (MFI) results of neat PBAT and PBAT-TPS were stable with slight changes throughout the seven reprocessing cycles and were comparable to LDPE. The properties of PBS, PLA, and PBAT-PBS blend, on the other hand, started to decrease after the second melt extrusion cycle. In addition, diferential scanning calorimetry (DSC), thermogravimetry (TGA), and dynamic mechanical analysis (DMA) results showed that LDPE, PBAT, and PBAT-TPS exhibited better thermal and mechanical stability as compared to PBS, PLA, and PBAT-PBS blend. The FTIR spectroscopy results showed that the characteristic peaks of C=O and C–O around 1710 cm-1 and 1046–1100 cm-1 for PBS, PLA, and PBAT-PBS decreased due to multiple thermal processing, while those of PBAT and PBAT-TPS were unafected. Scanning electron microscopy (SEM) micrographs of the fractured cross-sectional surface of PBS, PLA, and PBAT-PBS tensile specimens clearly evidenced the degradation of the biopolymers by severely fractured morphology as a result multiple reprocessing cycle. The results demonstrate that the fully biodegradable PBAT and PBAT-TPS can be mechanically recycled for at least seven cycles, and therefore, the service life of biodegradable polymers can be extended, and it is comparable with petroleum-based plastic.
Thermal-chemical and biodegradation behaviour of alginic acid treated flax fibres/ poly(hydroxybutyrate-co-valerate) PHBV green composites in compost medium
(Elsevier, 2019-11) Muniyasamy, Sudhakar; Ofosu, Osei; Thulasinathan, B; Rajan, AST; Ramu, SM; Soorangkattan, S; Muthuramalingam, JB; Alagarsamy, A
In this study, thermal-chemical and biodegradation behaviour of green composites based on flax fibres untreated and treated with alginic acid treated, and poly hydroxybutyrate-co-valerate (PHBV) were studied under composting conditions. The biodegradability of PHBV composites and neat PHBV were assayed by monitoring CO2 production from polymeric carbon under controlled aerobic composting conditions as per ASTM D5338 standard. During the biodegradation process, PHBV composites thermal-chemical and morphology properties were characterized by thermogravimetric analysis (TGA), fourier transform infra-red (FT-IR) and scanning electron microscopy (SEM) techniques. The ultimate biodegradation (mineralization) study results showed alginic acid treated flax/PHBV composites has higher rate of degradation than untreated flax/PHBV composite and neat PHBV. TGA analysis indicated that an increased t-onset temperature for alginic acid treated flax fibres/PHBV composites which was mainly due to the influence of 2% sodium alginate treated with flax fibres. FTIR results showed the increased degradation of PHBV composites was due to the hydrolytic chain scission mechanisms influenced by presence of alginic acid and flax fibres as compared to neat PHBV matrix. Morphological SEM analysis showed PHBV composites biodegradation were readily attacked by fungus but rather PHBV degradation by bacteria. This study found that the incorporation of flax fibres into PHBV matrix provides a benefit to the green composites with enhanced biodegradability.

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