Synthesis of Biodegradable Polylactic Acid Polymer By Using Lactic Acid Monomer (original) (raw)
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Degradation Behaviors of Different Blends of Polylactic Acid Buried in Soil
Energy Procedia, 2013
Polylactic acid (PLA), as the biodegradable polymer becomes more attention as a green material for industrial applications. Lipase-catalysed polymerization with Lecitase Ultra and Lipozyme TL IM were applied to synthesize PLA to decrease the chemical-catalysts utilization which having toxicity interferes in products. PLA products were characterized by end group/HPLC analyses for M n /M n n w determination. The results indicated that low molecular weight PLA could be successfully produced from commercial lactic acid by using the commercial lipases. With using Lipozyme TL IM as biocatalyst, obtainable M n and M w of PLA were 7,933 Da and 194 Da, respectively. For Lecitase Ultra used as biocatalyst obtainable M n and M w of PLA were 8,330 Da and 216 Da, respectively. Subsequently, the resulting PLA products from this method were prepared as PLA films blended with commercial PLA beads varying the blending ratios by casting on glass plate. Their degradable behaviors were studied under controlled soil burial laboratory conditions. The characteristics of PLA blend films were analyzed using visual observations, measuring weight loss, DSC and FTIR analysis. The results observed that the different blends ratios of PLA films showed more flexible than pure PLA film. Besides, the different blends of PLA films were disintegrated in soil within the short burial time.
Biodegradability of Poly (lactic acid), Preparation and Characterization of PLA/Gum Arabic Blends
Journal of Polymers and The Environment, 2008
In this study, the biodegradation of PLA films using microorganisms from Lake Bogoria (Kenya) were investigated. The biodegradation tests done using certain strains of thermophilic bacteria showed faster biodegradation rates and demonstrated temperature dependency. The biodegradation of the PLA films was studied using Gel Permeation Chromatography (GPC) and light microscopy. The biodegradation of PLA was demonstrated by decrease in molecular weight. The preparation and characterization of PLA/Gum Arabic blends were also investigated using DSC, TGA, TMA and NMR. In summary, the results obtained in this research show that PLA films undergo fast biodegradation using thermophiles isolated from Lake Bogoria. The PLA/GA blends studies show it is possible to prepare films of varying hydrophobic–hydrophilic properties for various applications.
The present study involves synthesis of polylactic acid (PLA) using purified lactic acid from fermented broth of Jackal jujube (Zizyphus oenophlia). A polyphenolic compound, humic acid (HA) of biological origin was incorporated to the PLA in order to reinforce the PLA chain without compromising its biodegradability and biocompatibility. Under optimized conditions of polymerization, modified L-PLA yield improved up to 93%. The molecular weight was found to be 6.4×105. Different physicochemical properties of the polymer were explored for its further application in different fields. Incorporation of intermolecular bond between PLA and HA was confirmed by FT-IR spectroscopy technique. Addition of HA not only reduced the crystallinity of PLA, but also had increased flexibility and elasticity to much greater extent. The results showed that, apart from enhancing the physicochemical properties of PLA, the process also had reduced the production cost of the polymer, while mitigating the demands of environmental protection agencies.
Journal of Engineering and Technological Sciences, 2015
Production of biodegradable polylactic acid (PLA) from biomassbased lactic acid is widely studied for substituting petro-based plastics or polymers. This study investigated PLA production from commercial lactic acid in a batch reactor by applying a direct melt polycondensation method with two kinds of catalyst, γ-aluminium(III) oxide (γ-Al 2 O 3) or zinc oxide (ZnO), in reduced pressure. The molecular weight of the synthesized PLA was determined by capillary viscometry and its structural properties were analyzed by functional group analysis using FT-IR. The yields of polymer production with respect to the theoretical conversion were 47% for γ-Al 2 O 3 and 35% for ZnO. However, the PLA from ZnO had a higher molecular weight (150,600 g/mol) than that from γ-Al 2 O 3 (81,400 g/mol). The IR spectra of the synthesized PLA from both catalysts using polycondensation show the same behavior of absorption peaks at wave numbers from 4,500 cm-1 to 500 cm-1 , whereas the PLA produced by two other polymerization methods-polycondensation and ring opening polymerizationshowed a significant difference in % transmittance intensity pattern as well as peak area absorption at a wave number of 3,500 cm-1 as-OH vibration peak and at 1,750 cm-1 as-C=O carbonyl vibrational peak.
Review on Characterization of Various Poly Lactic Acid based Biodegradable Composites
Juniper Online Journal Material Science , 2018
Composites materials are the material made up of two or more materials with different physical and chemical properties but the individual components remain separate and distinct in final product. Composites have become so vital due to their high effective stiffness and strength, availability, low cost, specific strength, better dimensional stability and mechanical properties, eco-friendly and biodegradable as compared to plastics and fibers. Among all the property now a day’s researchers concern is more on the biodegradable properties due to strict environmental rules and regulations. However always the non-biodegradable composites have more strength and stability, researchers adding various additives, blending fibres and resins which are biodegradable to bring the strength and stability on par with non-biodegradable composites. The biodegradable poly lactic acid composites has satisfactory thermal stability and mechanical rigidity. It can be reused and recycled. The rate of Biodegradability of PLA biodegradable composite is assessed in natural conditions. The main aim of this paper is to study the effect of various Resins, Fabrics and Additives on PLA biodegradable composite based on mechanical tests, DSC test, and to identify the best suitable material for various application.
Journal of Polymers and the Environment, 2020
Polylactic acid polymer (PLA) produced from renewable resources can be recycled at the end of life to constituent monomer, optically pure lactic acid (LA), by a combination of chemical and biological processes. Efficient application of this closed loop of LA-PLA plastics-LA can minimize accumulation of plastics waste that pollute land and oceans. Temperaturedependent hydrolysis of PLA in water to LA follows apparent first order decay kinetics after a short lag. A modified Gompertz equation can explain the overall hydrolysis process. Alkali increased the rate of hydrolysis of PLA and reduced the length of lag period compared to water alone. The stoichiometry of base added to LA released was 1.0. The highest lactic acid yield was 0.95 g g −1 of PLA. d-LA in the syrup obtained after hydrolysis of PLA-plastics was removed using an engineered Escherichia coli to produce a l-LA syrup with an optical purity ≥ 99%. These results show that thermochemical hydrolysis of PLA-based plastics to LA with optimum amount of base followed by bio-based purification to l-LA is an effective method of recycling PLA-plastics for reuse.
Synthesis of Polylactic Acid (PLA) by Polycondensation Method
International Journal of Engineering and Management Sciences, 2020
The Polylactic acid (PLA) is compostable and natural renewable sourced plastic type. Its mechanical properties quite similar to the PET, therefore the PLA is a good alternative for strongly ruled food industrial application. The PLA only has one critical attribute – the relatively low glass transition temperature. According to the relevant literature the glass transition of PLA is in the range of 40-70°C. In light of this fact, this material can be used only in that segments of food industrial field where the packaging process temperature are under of the lower limit of Tg range. The actual Tg of a material is highly depends on the molar mass and material structure, therefore the molar mass and the structure of material should be designed according to the future requirements of application and procedures.
Materials
Composite materials are emerging as a vital entity for the sustainable development of both humans and the environment. Polylactic acid (PLA) has been recognized as a potential polymer candidate with attractive characteristics for applications in both the engineering and medical sectors. Hence, the present article throws lights on the essential physical and mechanical properties of PLA that can be beneficial for the development of composites, biocomposites, films, porous gels, and so on. The article discusses various processes that can be utilized in the fabrication of PLA-based composites. In a later section, we have a detailed discourse on the various composites and nanocomposites-based PLA along with the properties’ comparisons, discussing our investigation on the effects of various fibers, fillers, and nanofillers on the mechanical, thermal, and wear properties of PLA. Lastly, the various applications in which PLA is used extensively are discussed in detail.
Degradation kinetics study of Poly lactic acid(PLA) based biodegradable green composites
Materials Today: Proceedings, 2020
The aim of the present study is to understand the effect of concentration of reinforcement and plasticizer on specific properties of the polymer matrix, by fabricating Poly lactic acid (PLA) based bio-composite. The bio-composite was prepared by solution casting method with PLA as the matrix, chloroform as the solvent, polyethylene glycol (PEG) as the plasticizer as well as compatibilizer, and microcrystalline cellulose (MCC) as the reinforcement. The degradation kinetics of PLA based composites was determined using the Coats-Redfern equation over a range of 1-5 wt % of MCC. Fabricated PLA based composites were evaluated for thermal stability, and morphology.
Now a days, polylactic acid (PLA) and its derivatives are receiving significant attention due to its versatile applications. The present study provides a deep insight on major structural and functional properties of novel PLA-HA polymer synthesized by incorporating humic acid (HA) in PLA. Topographical features of both pure and modified PLA have been studied using SEM and AFM to analyze their comparative surface microstructures. Incorporation of HA was found to enhance slightly the thermal stability profile of the polymer. However, reduction of Tg, Tm and degree of crystallinity has also been noticed, which in turn resulted in enhanced ductility and higher elongation at break. Moreover, improvement in radical scavenging properties, total available phenolics (0.075 μmole GAE/g film) and water absorption capacity (90.65%) has been observed which essentially suggested introduction as well as enhancement of several utility features, originally absent in pure PLA. The study thus predicts multifaceted applications of PLA-HA polymer, from industrial packaging to fabrication of biomedical devices depending on its superior characteristics as compared to pure PLA.