Thermal Resistant Polylactic Acid Packaging

A biodegradable packaging material with improved durability and barrier properties, comprising a paper substrate coated with a composition of polyhydroxyalkanoate (PHA) and two or more types of polylactic acid (PLA) with different melting indices. The PHA provides thermal stability and the PLA enhances barrier properties, while the combination of both enables the material to meet both industrial and household composting standards.

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Biaxially stretched film comprising polylactic acid with a tear strength of 50-100 N/mm, enabling both punching processability and heat resistance. The film is suitable for applications such as protective films for electronic devices, where it provides a balance of mechanical strength, thermal stability, and ease of processing.

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Recyclable packaging film with improved properties like heat resistance and durability compared to all-polyethylene films, while still allowing recycling. The film has an oriented base layer with a polar polymer layer and a stabilizing polyolefin layer. The stabilizing polyolefin improves dimensional stability during converting processes. The polar polymer layer provides heat resistance and appearance. The stabilizing polyolefin allows recycling compatibility. The base film has a converting strain of 0-0.75% at 75°C.

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Degradable plastic bottle for pesticide applications that can store pesticides for long periods without degradation issues. The bottle is made by blowing molding a composite resin mixture containing specific degradable polymers. The mixture includes polylactic acid (PLA), polybutylene adipate terephthalate (PBAT), polymethyl ethylene carbonate (PEC), polyglycolic acid (PGA), and calcium carbonate (CaCO3). The composite resin mixture allows improved mechanical properties, crystallinity, and barrier performance compared to using PLA alone. The bottle can degrade in composting conditions and has controlled degradation properties.

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A resin composition comprising a polylactic acid polymer and a β-methyl-δ-valerolactone polymer, which improves the tensile elongation at break of polylactic acid while suppressing a decrease in glass transition temperature.

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Biodegradable container made from a biodegradable resin composition that uses a specific type of biodegradable polymer called polyhydroxyalkanoate (PHA) with a high content of 4-hydroxybutyrate (4-HB) units. The composition has a melt flow index of 1.0 g/10 minutes or more when measured at 165°C. The container made from this composition has improved properties like impact resistance, chemical resistance, and water resistance compared to other biodegradable containers. It also has a compressive strength of 5 kgf/cm2 or more. The biodegradable container can be prepared by molding the biodegradable resin composition.

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Laminated article with improved oil resistance and crack resistance for packaging materials and containers made from biodegradable materials. The laminated article has a substrate layer like paper and a sealant layer containing a biodegradable polyhydroxyalkanoate (PHA) resin. The PHA resin has specific melting behavior: a highest melting peak at 130°C or higher and total crystalline melting enthalpy from 20 to 65 J/g. This PHA resin composition provides both good oil resistance and crack resistance in the sealant layer. The laminated article can be formed by extrusion lamination or thermal lamination processes.

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A biodegradable resin with enhanced flexibility, comprising a poly(lactic acid-b-3-hydroxypropionic acid) block co-polymer with a crystalline layer thickness of 1.0 nm to 14.0 nm, a molecular weight of 50,000 g/mol to 500,000 g/mol, and a composition of 10% to 30% poly(3-hydroxypropionic acid) and 70% to 90% polylactic acid. The resin exhibits a Young's modulus of 0.1 GPa to 5.0 GPa and can be used in various molded articles, including packaging materials.

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Biodegradable resin composition comprising a blend of polylactic acid (PLA) and polyhydroxyalkanoate (PHA) resins, wherein the PHA resin comprises a combination of 3-hydroxyhexanoate (3HH) and 4-hydroxybutyrate (4HB) repeating units, enabling the production of biodegradable films with improved mechanical properties, stretchability, and biodegradability.

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A biodegradable foam sheet for food containers that combines high thermal resistance, insulation, and anti-staining properties. The foam sheet is made from a polylactic acid (PLA) composition with a crystallinity of 40-60% and a melt viscosity of 100-500 Pa·s. The PLA composition contains a chain extender with two or more epoxy groups per molecule and has a bulk density of 0.063-0.250 g/cm3. The foam sheet is produced using a high-temperature extrusion process and has a surface roughness of 0.5-2.0 μm.

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This research paper aims to enhance the fatigue resistance of polylactic acid (PLA) in Material Extrusion (ME) by incorporating natural reinforcement, focusing on rotational bending fatigue. The study investigates the fatigue behavior of PLA in ME, using various natural fibers such as cellulose, coffee, and flax as potential reinforcements. It explores the optimization of printing parameters to address challenges like warping and shrinkage, which can affect dimensional accuracy and fatigue performance, particularly under the rotational bending conditions analyzed. Cellulose emerges as the most promising natural fiber reinforcement for PLA in ME, exhibiting superior resistance to warping and shrinkage. It also demonstrates minimal geometrical deviations, enabling the production of components with tighter dimensional tolerances. Additionally, the study highlights the significant influence of natural fiber reinforcement on the dimensional deviations and rotational fatigue behavior of printed components. The fatigue resistance of PLA was significantly improved with natural fiber reinforc... Read More

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A biodegradable plastic composition with improved processability and mechanical properties, comprising a blend of polylactic acid (PLA) and suberin or suberin-based compounds extracted from plant sources, such as cork and potato periderm. The composition exhibits enhanced plasticity and biodegradability compared to conventional PLA-based bioplastics, making it suitable for various applications including disposable products, packaging, and agricultural materials.

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Polylactic acid (PLA) is a biodegradable thermoplastic made from lactic acid monomers obtained through fermented glucose in crops like wheat and corn. PLA has numerous applications, including industrial packaging, biomedical equipment, and membranes, due to its low toxicity, biodegradability, and recycling potential. However, little is known about the short-term aging effects of particulate reinforced PLA composites in complex environments. This study investigates the chemical endurance of various PLA composites before and after exposure to different chemicals and hygrothermal conditions. The results reveal that the fabrication processing method greatly affects the degradation rate. The PLA/Carbon Fiber Powder (CFP) samples had the highest chemical resistance towards degradation in 1% HNO followed by 2% NaOH with a maximum mass increase of 2.8% and 3.9% respectively. The PLA/CFP samples showed lowest chemical resistance under a combination of water and aging temperature, with an average maximum weight gain of 9.64% throughout the three CFP loadings. Continuous test for 15wt% CFP sam... Read More

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Hydrolysis-stabilized polyester compositions comprising a monomeric carbodiimide of formula (I) with improved hydrolysis protection in PET and PLA, particularly for high-temperature processing applications. The carbodiimide stabilizer is characterized by a specific molecular structure and NCN content, enabling effective moisture binding and long-term stability in polyester materials.

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To enrich the properties of polylactic acid (PLA)-based composite films and improve the base degradability, in this study, a certain amount of poly(propylene carbonate) (PPC) was added to PLA-based composite films, and PLA/PPC-based composite films were prepared by melt blending and hot-press molding. The effects of the introduction of PPC on the composite films were analyzed through in-depth studies on mechanical properties, water vapor and oxygen transmission rates, thermal analysis, compost degradability, and bacterial inhibition properties of the composite films. When the introduction ratio coefficient of PPC was 30%, the tensile strength of the composite film increased by 19.68%, the water vapor transmission coefficient decreased by 14.43%, and the oxygen transmission coefficient decreased by 18.31% compared to that of the composite film without PPC, the cold crystallization temperature of the composite film increased gradually from 96.9 C to 104.8 C, and PPC improved the crystallization ability of composite film. The degradation rate of the composite film with PPC increased s... Read More

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A biodegradable resin composition for extrusion coating that exhibits excellent mechanical properties, including thermal bonding strength and processability, even at low temperatures. The composition comprises 5-95% by weight of polyhydroxyalkanoate (PHA) resin, with a melt flow index of 5-60 g/10 min and a weight average molecular weight of 30,000-1,200,000 g/mol. The PHA resin contains 0.1-50% by weight of 4-hydroxybutanoate (4-HB) repeating units, which enables the composition to maintain its mechanical properties during processing at temperatures below 260°C.

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A biodegradable triblock copolymer of polybutylene succinate (PBS) and polylactic acid (PLA) that enhances the mechanical and barrier properties of PBS-based bioplastics. The copolymer, PLLA-b-PBS-b-PLLA, is synthesized through a cost-effective and reproducible method using a PBS macroinitiator. The copolymer is characterized by a PBS block with a molecular weight of 1500-40,000 g/mol and a PLLA block with a molecular weight of 4000-200,000 g/mol. The copolymer is used as an additive in PBS-based bioplastics to improve their mechanical strength, thermal stability, and barrier properties against gases and water vapor.

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Biodegradable packaging materials that can be used for food preparation and storage. The materials consist of a continuous polylactic acid matrix with discrete polycaprolactone domains. The polycaprolactone domains can be present as separate components within the polylactic acid matrix, providing a controlled release of the material's biodegradability properties. This composition enables the creation of biodegradable packaging that can be used both as containers for food preparation and as containers for food storage.

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A biodegradable foamed sheet comprising a polylactic acid (PLA) and a filler, wherein the sheet exhibits a compressive stress of 0.2 MPa or less when the cushioning coefficient is 10 or less, and a puncture strength of 2 N or more when the sheet thickness is 2 mm. The PLA is foamed using a kneading process that employs a compressible fluid to achieve uniform dispersion of the filler, resulting in a sheet with enhanced cushioning and strength properties.

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This study examines the tribological characteristics of polymer-composites produced by fused deposition modeling (FDM), with a particular emphasis on composite materials where polylactic acid (PLA) is used as matrix material and Al metal powder is used as a reinforced material. The study's objectives are to compare the wear resistance capacities of PLA and PLA-Al-based composite materials prepared by three dimensional (3D) printing process. The samples were manufactured by the FDM-based manufacturing process. It has revealed that the PLA-Al composite had significantly better wear resistance than PLA. The PLA-Al sample has exhibited the lowest wear rate (501 m), whereas the PLA sample has exhibited a comparatively higher wear rate of (1,188 m). These findings have major implications for the automobile sector, oil and gas industry, and marine applications that require materials with excellent wear resistance.

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Polylactic Acid (PLA) is a biodegradable and bioactive polyester derived from renewable sources such as corn and sugar cane. Because PLA is eco-friendly, researchers have recently tried to make PLA replace other polymers that cause greenhouse gases and other pollution. However, for many industries, PLA has limitations of unsatisfactory toughness, heat resistance, etc. In this case, it is necessary to invest in the modification of PLA, which can offer PLA desired traits to adapt to different situations. This review focuses on the recent modifications that successfully improve PLA to fit the aims, as well as the advantages and disadvantages of each method that is used for modification. There is no doubt that these methods provide a path to expand the use of PLA in different fields, such as packaging, medicine, agriculture, and textiles. The paper concludes by emphasizing the need for continued research and technological development to fully release PLA's potential in promoting a sustainable and eco-friendly future.

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Polylactic acid (PLA) is widely known for its biocompatibility, biodegradability, and high transparency. However, it still has varied limitations such as flammability, UV sensitivity, and poor oxygen barrier properties. To address these issues, a bio-based compound, hexasubstituted cyclotriphosphazene (HVP), was synthesized by using vanillin and hexachlorocyclotriphosphazene to enhance the overall performance of PLA. The resulting PLA/HVP composites demonstrated improved mechanical strength and UV resistance. Specifically, PLA/3HVP, with a 3 wt% HVP loading, achieved a UL-94 V-0 rating and a high limiting oxygen index of 26.5 %. Cone calorimeter tests revealed that PLA/3HVP possessed a significantly longer ignition time and a lower peak heat release rate compared to pure PLA. These burning testing results indicated the enhanced fire resistance. Additionally, the oxygen transmission rate of PLA/3HVP was reduced by 81.1 % compared to pure PLA. When used as food packaging, the weight loss of mangoes covered with PLA/3HVP film was 2.2 % after 7 days, compared to 2.5 % with pure PLA film,... Read More

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Abstract Polylactic acid (PLA), derived from renewable resources, has the advantages of rigidity, thermoplasticity, biocompatibility, and biodegradability, and is widely used in many fields such as packaging, agriculture, and biomedicine. The excellent processability properties allow for melt processing treatments such as extrusion, injection molding, blow molding, and thermoforming in the preparation of PLAbased materials. However, the low toughness and poor thermal stability of PLA limit its practical applications. Compared with pure PLA, conditions such as processing technology, filler, and crystallinity affect the mechanical properties of PLAbased materials, including tensile strength, Young's modulus, and elongation at break. This review systematically summarizes various technical parameters for melt processing of PLAbased materials and further discusses the mechanical properties of PLA homopolymers, fillerreinforced PLAbased composites, PLAbased multiphase composites, and reactive composite strategies for PLAbased composites.

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Polylactic acid (PLA) possesses characteristics such as biodegradability, ease of processing, and environmental friendliness, making it an ideal alternative to petroleum-based polymers. However, PLA has drawbacks such as susceptibility to hydrolysis and sensitivity to ultraviolet (UV) light, limiting its application in certain areas. In this study, poly(carbazole diimide) (PCDI) and the epoxy chain extender Joncryl ADR4468 (CE) were employed as a synergistic anti-hydrolysis agent for PLA, and tannic acid (TA) was used as a UV-resistant agent. A melt-blending process was employed to prepare PLA composite materials with enhanced resistance to both hydrolysis and UV radiation. The results indicate that the addition of PCDI-TA-CE significantly improved the performance of PLA. After 8 h of hydrolysis at 80 C, the tensile strength of PLA increased from 38.31 MPa for pure PLA to 77.69 MPa with the incorporation of PCDI-TA-CE. The elongation at break increased from 0.6% to 1.5%, and the Ultraviolet Protection Factor (UPF) value elevated from 3.19 for pure PLA to 503.46.This demonstrates tha... Read More

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The deterioration of polylactic acid packaging materials due to moisture and insulation failure is a significant factor. Enhancing the long-term stability of polylactic acid in hot and humid environments is crucial for electronic components to adapt to complex working conditions and high power density. In this study, we prepared a hydroxy-terminated polydimethylsiloxane modified fluorinated graphene and utilized self-assembly to construct a micro-nano structure hydrophobic surface on the polylactic acid material. This approach effectively enhances the surface hydrophobicity and moisture resistance of polylactic acid. Moreover, the introduction of hydroxy-terminated polydimethylsiloxane modified fluorinated graphene filler enables the creation of an "arch bridge" energy band structure within polylactic acid, facilitating carrier migration regulation. By employing this method, we achieve a synergistic improvement in the moisture resistance and insulation performance of polylactic acid.

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In this paper thermo-mechanical behavior of 4D printed Polylactic Acid (PLA) was investigated, focusing on its response to varying strain rates and temperatures below the glass transition temperature. Dynamic mechanical analysis and uniaxial tensile tests confirmed PLA's dependency on strain rate, showcasing its sensitivity to external stimuli. Stress-strain curves exhibited typical thermoplastic behavior, with yield stresses varying with strain rates, underscoring PLA's responsiveness to different deformation speeds. Clear strain rate dependence was observed, particularly at quasi-static rates, with temperature and strain rate fluctuations significantly influencing PLA's mechanical properties, including yield stress and deformation behavior. Isothermal compression tests demonstrated predictable stress-strain curves with distinct yield points, while adiabatic tests reveal additional complexities such as heat accumulation leading to further softening. Thermal imaging revealed temperature increase during deformation, highlighting the material's therm... Read More

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The integrity of a package must be maintained by a material that can be heat sealed, particularly in medical, food, and pharmaceutical packaging applications. Obtaining an appropriate heat seal in packaging is crucial since, compared to package failure, heat seal failure is a more common reason for product degradation. Material selection and packaging methods should be evaluated carefully to choose the proper material that can effectively function under proper conditions. Hermetic seal property ensures the effectiveness of barrier layers in preventing oxygen permeation, loss of odor, and transmission of water vapor. Polylactic acid (PLA) is one of the biodegradable polymers with the greatest potential for heat sealing and thermal processing. To establish manufacturing protocols, verify seal effectiveness, and ensure product integrity, it is essential to consider the effects of controlling process parameters during package design. Therefore, to undercover the role of PLA structure on its properties, the factors impacting its heat-sealing feature are elaborated on in this chapter. More... Read More

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A variety of industries, including automotive, agriculture, and packaging, are drawn to polylactic acid (PLA) because of its excellent mechanical properties, processability, and biocompatibility. The food packaging industry is becoming increasingly interested in replacing traditional polymers with biopolymers. This is why PLA has significant potential for use in different types of food packaging such as films, sheets, containers, and bottles. However, the high gas permeability and poor moisture barrier properties of PLA have hindered its application in this area. For example, the poor gas and moisture barrier properties make it suitable only for packaging products with a short shelf life and highbreathing foods. The permeability problem of PLA can be overcome by several strategies, including polymer blending, additives like nucleating agents and plasticizers, and using a barrier coating in films and other products. For a better understanding of PLA's structure- property relationships, the barrier properties and the basic parameters affecting its permeability are discussed in this cha... Read More

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Heat-resistant nonwoven web for packaging applications that can withstand high temperatures like boiling water without degrading. The web is made by melt-bonding a mixture of levorotatory and dextrorotatory polylactic acid (PLA) polymers instead of using pure PLA. This creates a stereocomplex between the two forms of PLA that has improved thermal and mechanical properties compared to pure PLA. The web can be produced by melt-bonding methods like spun bonding or melt blowing. The mixed PLA stereocomplex fibers are assembled into a web structure with an inner layer of fibers made from the mixed PLA and an outer layer of pure PLA fibers. This provides insulation for the inner mixed PLA layer during sealing. The mixed PLA inner layer can have lower melting point fibers to soften for sealing.

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Polylactic acid (PLA), derived from renewable resources, has good biodegradability and mechanical properties. However, poor water vapor and oxygen barrier properties limit its wide application in packaging. In this work, we designed and then synthesized a series of PLA, including C16-PLLAx-b-PDLAy block polymers and C16-PDLAy-b-PLLAx block polymers by a two-step-controlled ring-opening polymerization reaction of L-lactide or D-lactide. The synthetic routes, chemical and aggregate structures, thermal and tensile properties, and barrier performances of the synthesized PLA samples were investigated. The synthesized block-structured PLA contained only crystallites of the stereocomplex form and was thermally stable at almost the same level as homopolymerized PLA of comparable molecular weight, and its melting point increased by more than 40 C. The block PLA films showed an increased tensile strength and elongation at break with increasing molecular weight and exhibited brittle fracture as homopolymerized PLA did. In barrier performance tests, the block PLA films outperformed the homopoly... Read More

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Polylactic acid (PLA) has intrigued widespread attention as a biodegradable and environmentally friendly polymer, and recent research has revealed that the use of porous PLA in heat sinks for thermal management materials offers promising development potential. However, the heat transfer performance is closely related to its structure theoretically, whether it is virgin, and how the pore structure affects its heat transfer. Therefore, a novel approach is proposed to address this issue by preparing porous PLA through 3D printing at low complexity and cost, the combustion performance is employed to evaluate the heat transfer indirectly, and the higher burning speed represents higher efficient heat transfer. A new framework is developed to investigate combustion performance and three series of PLA with different pore structures in pore shape, size, and interval are studied by combining experimental tests, respectively. It demonstrates that adjusting the pore structure of PLA significantly alters its combustion performance, evidenced by significant variations in flame growth index, which ... Read More

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Abstract The post-processing treatment of isostatic compression with different temperatures is improved with the interlayer bonding of the polylactic acid (PLA) parts. This bonding enhanced the tensile strength, percentage of strain, and elastic modulus of post-processed PLA samples through the tensile test. Here, the tensile strength is improved by about 127 % compared to untreated PLA due to interlayer bonding and the compressive force with 140 C. Compression and flexural tests are utilized to examine the post-processed parts compression and flexural strength. It significantly improves the compressive and flexural strength of the post-processed parts, increasing to about 55 % and 64.5 % compared with the untreated PLA parts. Additive manufacturing of PLA parts is significantly progressed in the 3D printing of biodegradable and eco-friendly components through a layer-by-layer deposition.

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The goal of this study is to provide first-hand knowledge to the industrial community on the mechanical properties of structurally graded materials (polylactic acid/ceramic-reinforced polylactic acid) wall fabricated through fused filament fabrication. Structurally graded materials are inhomogeneous materials that consist of two or more materials to produce a final structure with distinctive material properties. Because of their specific gradient, structurally graded materials are commonly used in various applications such as aerospace, medicine, optoelectronics, biotechnology, etc. These applications have certain requirements and significant properties such as thermo-mechanical resistance and chemical stability. Filaments of polylactic acid were deposited over ceramic-reinforced polylactic acid to fabricate structurally graded material walls. Coupon studies revealed that structurally graded materials exhibited mechanical properties (tensile strength: 19.1 0.3 MPa, flexural strength: 100.1 0.23 MPa, compressive strength: 64.6 2.35 MPa, impact energy: 1.32 0.038 J, and hardnes... Read More

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Plastic materials have revolutionized modern life, particularly in the domain of food packaging, owing to their versatility, lightweight nature, and ease of processing. However, the environmental ramifications of non-degradable plastics have raised concerns. Polylactic acid (PLA), derived from renewable sources, represents a sustainable alternative due to its biodegradability and exceptional barrier, mechanical, and safety properties. Nevertheless, the high UV transmittance of PLA limits its use for photosensitive food and pharmaceutical packaging, where UV radiation can lead to nutritional loss and spoilage. Various methods have been explored to enhance the UV-blocking capabilities of PLA, including the integration of inorganic nanoparticles and surface coatings. Despite advancements, these approaches often compromise the inherent transparency of PLA. Incorporating large conjugated groups can maintain transparency but introduces additional challenges. This paper reviews modification methods to enhance PLAs UV-barrier properties and anticipates its expanded utility in food and drug ... Read More

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To improve the toughness and heat resistance of polylactic acid (PLA), polybutylene succinate (PBS) was sufficiently blended with PLA as the base matrix, and the glass fiber (GF) that was modified with 3-aminopropyltriethoxysilane (KF-GF) was added as the reinforcement. The results demonstrated a noteworthy boost in both mechanical and heat resistance properties when employing KH-GF, in comparison to pristine GF. When the content of KH-GF reached 20%, the tensile, flexural, and IZOD impact strength of the composites were 65.53 MPa, 83.43 MPa, and 7.45 kJ/m2, respectively, which were improved by 123%, 107%, and 189% compared to the base matrix, respectively. This enhancement was primarily attributed to the stronger interfacial adhesion between KH-GF and the PLA/PBS matrix. Furthermore, the Vicat softening temperature of the composites reached 128.7 C, which was a result of increased crystallinity. In summary, the incorporation of KH-GF into PLA/PBS composites resulted in notable enhancements in their mechanical properties, crystallinity, and thermal characteristics. The high performa... Read More

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In this study, polylactic acid PLA was melt blended with bis(2-(2-butoxyethoxy)ethyl) adipate, tributyl citrate and/or sorbitan monooleate.The thermo-mechanical analysis of plasticized PLA highlighted an improvement in its behavior.Thus, the plasticization of PLA with the tested esters favored the lowering of its vitrification temperature and the bending resistance of the tested materials at room temperature varied in an area of interest for all the tested plasticizers.No significant difference was noted between the maximum flexural strengths and the elongation at deformation recorded at 25C and those at 4C for the three recipes.Also, the weight loss of PLA recipes in contact with water decreases in the presence of hydrophobic plasticizers.

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Nowadays, polylactic acid (PLA) has been one of the most important packaging materials in daily life. PLA is eco-friendly because it can be made from renewable resources and is degradable, but it also has a drawback that is lack of toughening. In this review, papers about 3 main methods that could help improve the toughening of the PLA have been collected. They are blending, copolymerization and composition. Blending is a physical method to make the materials uniformly to improve the properties of the material. Copolymerization is the reaction of polymerizing various compounds into one substance under certain conditions. Composition is the termination of reaction by combining two growing free radicals to form a saturated macromolecule. This work will give some exact examples to improve the toughening of the PLA. It is expected that there will be better research methods and materials that are able to improve the toughness of PLA in the future.

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This study aims to present the authors' recent research investigating the mechanical and thermo-mechanical properties of commercial polylactic acid (PLA) polymer. Samples were manufactured by 3D printing of fused filament fabrication (FFF) and tests were performed according to ASTM International standards for polymers D638, D695 and D790. All test samples were made using the same printing process parameters. The static mechanical tests consisted of tensile and flexural loadings at various temperature ranges, from room temperature to elevated temperature (25C, 40C and 50C, respectively). For ensuring that the additively manufactured products can resist severities of real-life applications, thermal stability under mechanical load tests (HDT - heat deflection temperature) were carried out. The temperature influence on the mechanical and thermomechanical properties was determined and presented, and a synthesis of the characteristics was made in accordance with the applications of products based on the studied material.

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Abstract Polylactic acid (PLA) is a thermoplastic polyester that has received widespread attention for its environmentally friendly origin and excellent performance, and its potential to address the current problems of severe white pollution and scarcity of petroleum resources. This article focuses on the synthesis, modification, degradation and application of PLA. The main focus is on the modification of PLA with different environmentally friendly materials (natural organic materials, biodegradable polymers, inorganic minerals) in blends for defects such as the brittleness of PLA. In addition, the applications of PLA composites in the fields of construction, medical, packaging and oil and water separation are also introduced, which hopefully will provide some help to the promotion of PLA.

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Thermal and physico-mechanical properties of polyhydroxyalkanoates of Rhodococcus erythropolis Au-1, Pseudomonas sp. PS-17, Azotobacter vinelandii N-15 and polyhydroxybutyrate/polylactide mixtures were identified. Modifying polyhydroxybutyrate with polylactide improves physical and mechanical characteristics such as heat resistance, rigidity, and brittleness. An increase in the content of polylactide in mixtures leads to a decrease in the thermal stability of the samples and an increase in relative elongation. Polyhydroxybutyrate/ polylactide mixtures are recommended as packaging materials for food, agricultural, and pharmaceutical products.

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Polylactic acid is a thermoplastic polymer material known for its excellent biocompatibility, although it suffers from subpar rheological and mechanical properties. In this study, an investigation was carried out to assess how low filling degree, low melting point tinlead alloy powder affects the mechanical and rheological properties of the PLA matrix during the injection molding process. The results of the study indicated that SnPb alloy powder could effectively enhance the melt flow of PLA during processing and serve as a solid filler after molding, resulting in a significant improvement of the material's mechanical properties.

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Abstract In this paper, the research findings about the impact of polydopamine and tannic acid coatings on specific thermal properties of polylactide are discussed. The influence of deposited coatings on the resistance to oxidation, heat resistance, and the temperatures of phase transitions was determined. Therefore, the oxidation induction temperature, thermogravimetry, and differential scanning calorimetry studies were carried out. To gain a deeper understanding of the findings, mass measurements for the samples before and after the deposition process were conducted, as well as scanning electron microscopy studies. Studies have shown that the application of coatings can improve the resistance of polylactide against oxidative and thermal degradation. However, these coatings have minimal impact on the intensity and temperature of phase transformations. The polylactide showed increased thermal resistance when coated with polydopamine, whereas tannic acid coating was found to be more effective in increasing oxidation resistance. The differences observed were likely caused by variations... Read More

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Polylactic acid (PLA) has attracted much attention because of its good biocompatibility, biodegradability, and mechanical properties. However, the slow crystallization rate of PLA during molding leads to its poor heat resistance, which limit its diffusion for many industrial applications. In this review, the relationship between PLA crystallization and its molecular structure and processing conditions is summarized. From the perspective of the regulation of PLA crystallization by organic nucleating agents, the research progress of organic micromolecule (e.g., esters, amides, and hydrazides), organic salt, supramolecular, and macromolecule nucleating agents on the crystallization behavior of PLA is mainly introduced. The nucleation mechanism of PLA is expounded by organic nucleating agents, and the effect of the interaction force between organic nucleating agents and PLA molecular chains on the crystallization behavior of PLA is analyzed. The effects of the crystallization behavior of PLA on its mechanical properties and heat resistance are discussed. It will provide a theoretical ref... Read More

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Abstract Among the interesting thermal properties of polymeric materials is questionable their ability to transfer heat. The last decades have shown a significant expansion of manufacturing parts from polymeric materials using 3D printing processes. It is known that these processes allow changing the values of some input factors in the 3D printing workflow, which also leads to a change in the way the polymer material is arranged in part and, therefore, to a change in the capacity of the polymer material to transmit heat. To better understand how the variation of some input factors in the 3D printing process can change the way heat is transferred in test samples of polylactic acid (PLA) manufactured by 3D printing, a relatively simple device is designed whereby one of the surfaces of the test sample comes into contact with an aluminum alloy part heated using electrical resistance. Recording images using an infrared video camera helped to complete the information on how heat is transmitted through the test sample.

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Polylactic acid (PLA) is a popular 3D printing material with a high decomposition rate and is used in various environmentally friendly applications such as biomedical and food-grade packaging. This work is focused on studying the properties of 3D-printed PLA samples irradiated with gamma radiation at the dosages of 5, 10, and 15 KGy using cobalt-60 gamma irradiation and is examined for the mechanical and thermal properties. The layer thickness of 0.4 mm and a rectilinear infill pattern with a 100% density is used. Mechanical properties such as tensile, flexural, and Izod impact properties are studied. Dynamic mechanic analysis (DMA), differential scanning calorimetry (DSC), dilatometer, and thermal conductivity are used to study thermal stability. The effect of gamma irradiation on these mechanical and thermal properties is studied, and these studies show that gamma irradiation affects the mechanical and thermal properties of PLA.

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Polylactic acid (PLA) is recognized as a promising alternative to traditional petroleum-based plastics due to its excellent biodegradability and well-balanced mechanical properties. Nevertheless, the disadvantages of PLA such as flammability in fire, susceptibility to UV light attack, and slow natural degradation rate limit its application and recovery in high-security areas. In this work, a spherical chitosan-based additive DMPC-Al with mirror-symmetric internal structure was assembled by layer-by-layer electrostatic reactions, resulting in PLA characterized excellent comprehensive performances. When 7 wt% DMPC-Al was added into PLA, the LOI value of the composite PLA/7DMPC-Al was increased to 29.6%, and UL-94 reached V-0 grade without any molten droplets. The peak heat release rate and total heat release rate were reduced by 13.5% and 16.2%, respectively, and the carbon layer was highly self-expanding. In addition, the UPF of PLA/7DMPC-Al was increased to 34.45 from 0.45 of pure PLA, blocking most of the UV light attacks and extending the service life of PLA. Surprisingly, DMPC-Al ... Read More

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Abstract Prototype development nowadays can rarely be imagined without 3D printing. In the fastmoving electronics industry, 3D printing is a good way to react quickly to changing developments, for example, when it comes to heat sinks made of thermally conductive material. 3D printing of thermally conducting plastics, which are also electrically insulating, is an ideal candidate for the rapid generation of heat sink. Nevertheless, 3D printing also shows some drawbacks in regard to properties of the printed parts, as porosities or layer adhesion, emerging from layer deposition in the process. Therefore, the aim of this work was to investigate the influence of the orientation of fillers on the thermal conductivity of filled polylactic acid (PLA). PLA was filled with amounts of 1545 wt.% of boron nitride and aluminum granules and printed into heat sinks in two different orientations to investigate this influence on the thermal conductivity. The printed heat sinks were then placed on a heated aluminum block and the thermal transport was examined with an infrared camera. It could be show... Read More

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The semi-rigidity of the polylactic acid (PLA) molecular chain makes it brittle, poor impact resistance and barrier properties, which severely limits its practical applications. In this paper, a bio-based reactive plasticizer epoxy soybean oil (ESO) was used to improve the mechanical and barrier properties of maleic anhydride grafted polylactic acid (MAPLA) by the chemical reaction between the epoxy and anhydride group. Firstly, the optimum curing conditions were 93.5 C, 100 C, and 110.8 C for 2 h. The effects of different mass fractions of ESO on the properties of MAPLA-ESO (ME) films were systematically investigated. It was found that when the content of ESO was 10 wt%, the tensile properties of the resulting ME films were the best, with a tensile strength of 35.2 MPa. And it had an elongation at break of 20.0 % and toughness of 5.4 MJ/m3, which increased to 690 % and 675 %, respectively, compared with pure MAPLA films. The chemically crosslinked ME films also displayed excellent water resistance, well degradation, low migration properties, and better performance than that of co... Read More

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Polylactic acid (PLA) is a kind of biopolymer made from non-conventional resources. It is biodegradable and has high mechanical properties. However, its use as the packaging material in the food-packaging sector is limited due to its brittleness and porosity. Therefore, to reduce the brittleness and improve the barrier properties, the compression-molded PLA/ESO films were surface treated with N2 plasma. Water vapour permeability, migration and differential scanning calorimetry tests have been carried out to assess the surface barrier performance and thermal properties of the manufactured films. The surface-treated PLA/ESO showed better barrier properties than pure PLA and PLA/ESO. The water vapor transfer rate of surface-treated PLA/ESO was 3.35 % lower than the PLA/ESO. The improvement in barrier properties, as well as the reduction in glass transition temperature, could increase the potential of the material for packaging.

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Due to their high sensitivity to temperature and humidity, the applications of polylactic acid (PLA) products are limited. The stereo-complexation (SC) formed by poly(L-lactic acid) (PLLA) and its enantiomer poly(D-lactic acid) (PDLA) can effectively improve the heat resistance and hydrolysis resistance of PLA products. In this work, the blended melt-spinning process of PLLA/PDLA was carried out using a polyester fiber production line to obtain PLA fiber with a complete SC structure. The effects of high-temperature tension heat-setting on the crystalline structure, thermal properties, mechanical properties, and hydrolysis resistance were discussed. The results indicated that when the tension heat-setting temperature reached 190 C, the fiber achieved an almost complete SC structure, and its melting point was 222.5 C. An accelerated hydrolysis experiment in a 95 C water bath proved that the SC crystallites had better hydrolysis resistance than homocrystallization (HC). The monofilament strength retention rate of SC-190 fiber reached as high as 78.5% after hydrolysis for 24 h, which ... Read More

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