Techniques to Improve Crystallization in 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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A biodegradable composite comprising a biodegradable polymer and bio-crystals, wherein the bio-crystals are in a concentration of between 1 wt % to 50 wt % of the biodegradable polymer. The composite exhibits improved mechanical properties compared to the polymer alone, including enhanced tensile stress, modulus, and toughness. The bio-crystals can be amino acids, such as L-tyrosine, and are dispersed homogeneously within the polymer matrix. The composite is suitable for various applications, including packaging materials, films, foams, hydrogels, and aerogels.

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Film comprising a poly(3-hydroxyalkanoate) resin and a polylactic acid-based resin, where the polylactic acid-based resin has a melting point peak below 170°C. The film is produced by blending the poly(3-hydroxyalkanoate) and polylactic acid-based resins in a specific ratio, with the polylactic acid-based resin exhibiting a melting point below 170°C. The film can be stretched to achieve high strength and resistance to deformation without compromising its integrity.

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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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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 with enhanced thermal resistance, insulation, and strength, comprising a polylactic acid (PLA) resin composition with a high D- or L-lactic acid content (98 mol% or greater) and a mean volume diameter of sheet silicate grains (10-200 μm). The PLA resin composition has a high melt viscosity, achieved through reactive extrusion with a chain extender, and is processed at a temperature range of 200-240°C. The foam sheet exhibits excellent thermoformability and can be used to produce molded products with improved thermal resistance.

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A biodegradable foam sheet made from a polylactic acid (PLA) resin composition that exhibits excellent moldability, biodegradability, strength, thermal insulation properties, and thermal resistance. The PLA resin composition comprises a high-optical-purity PLA resin with a weight-average molecular weight of 180,000 to 320,000 and a terminal hydroxyl group content of 0.3 to 1.4. The composition also includes an epoxy group-containing compound with an epoxy equivalent of 170 to 350. The foam sheet has a cold crystallization enthalpy of 20 J/g or greater and a recrystallization enthalpy of 20 J/g or greater.

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Polylactic acid (PLA) has inherent drawbacks, such as its amorphous structure, which affect its mechanical and barrier properties. The use of nanofibrillated cellulose (NFC) mixed with PLA for the production of composites has been chosen as a solution to the above problems. A PLA/NFC composite was produced by solution casting. Before use, the cellulose was modified using a silane coupling agent. The composite films were investigated via X-ray diffraction, as well as by mechanical, physical, thermal analyses and by differential scanning calorimeter. The crystallinity was four times that of pure PLA and the water vapor transmission rate decreased by 76.9% with the incorporation of 10 wt% of NFC. The tensile strength of PLA/NFC blend films increased by 98.8% with the incorporation of 5 wt% of NFC. The study demonstrates that the addition of NFC improved the properties of PLA. This provides a solid foundation for the enhancement of the performance of PLA products.

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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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A polylactide resin composition with improved crystallinity, comprising a polylactide resin, a first nucleating agent, and a second nucleating agent, wherein the composition is heat-treated at 25-120°C for 1-30 minutes to enhance crystallization. The first nucleating agent is a bio-based organic compound, such as uracil or orotic acid, while the second nucleating agent is a conventional inorganic compound, such as talc or mica. The heat treatment step enables the synergistic effect of the two nucleating agents to achieve higher crystallinity and improved thermal properties.

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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 biobased, biodegradable, non-toxic polymer widely considered for replacing traditional petroleum-based polymer materials. Being a semi-crystalline material, PLA has great potential in many fields, such as medical implants, drug delivery systems, etc. However, the slow crystallization rate of PLA limited the application and efficient fabrication of highly crystallized PLA products. This review paper investigated and summarized the influence of formulation, compounding, and processing on PLA's crystallization behaviors and mechanical performances. The paper reviewed the literature from different studies regarding the impact of these factors on critical crystallization parameters, such as the degree of crystallinity, crystallization rate, crystalline morphology, and mechanical properties, such as tensile strength, modulus, elongation, and impact resistance. Understanding the impact of the factors on crystallization and mechanical properties is critical for PLA processing technology innovations to meet the requirements of various applications of PLA.

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Polylactide (PLA) resin composition with improved crystallinity and reduced glass transition temperature, achieved by combining a first nucleating agent that enhances high molecular weight chain mobility and a second nucleating agent that lowers the glass transition temperature of the amorphous region.

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The toughening modification of polylactic acid (PLA), one of the most promising sustainable plastics, usually comes at the expense of other characteristic properties, such as mechanical strength, transparency, and environmental friendliness. In this work, a polyurethane copolymer elastomer (PCLA-PLA-U) containing three different blocks, i.e., PLA, copolymer synthesized from random copolymerization of -caprolactone and lactide (PCLA), and polyurethane (PU), with different functions has been designed and synthesized. The elastomer's compatibility with the matrix is enhanced by the addition of PLA blocks, therefore effectively regulating the size and dispersion of the toughening phases. PCLA blocks, as the main components, endow the PU copolymer with good transparency and a refractive index matching with PLA matrix. Meanwhile, the physical cross-linked network constructed based on PU blocks endows the toughening phase with an excellent ability to induce matrix elastic deformation, thereby significantly improving the toughness of PLA. When the addition of PCLA-PLA-U is low (<5%), the mo... Read More

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A polylactic acid (PLA) resin composition for producing biodegradable foamed PLA products, comprising a PLA resin with a melt viscosity of 2,000 to 40,000 Pa·s at 190°C and a molecular weight distribution with a region of Mw ≤ 1,000 of ≤ 10% and a region of Mw ≥ 500,000 of ≥ 20%. The composition enables the production of foamed PLA products with improved mechanical properties, thermal stability, and biodegradability.

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A biodegradable foamed polylactic acid (PLA) sheet with improved properties for packaging and cushioning applications. The sheet is manufactured through a novel process involving melting, kneading, and expansion of PLA resin in the presence of a compressive fluid, followed by purging and expansion. The resulting sheet exhibits a low bulk density, controlled melt viscosity, and reduced crystallinity, enabling enhanced flexibility, cushioning performance, and wrapping followability. The sheet can be used as a raw material for various molded products, offering a sustainable alternative to traditional packaging materials.

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Blends of polylactic acid (PLA) with amorphous polyhydroxyalkanoate (aPHA) are less brittle than neat PLA, thus enabling their use as biodegradable packaging. This work investigated the impact of recycling on the properties of neat PLA and PLA/aPHA blends with 90 and 75 wt. % PLA. After the materials were subjected to five heat histories in a single-screw extruder, the mechanical, rheological, and thermal properties were measured. All recycled compounds with 100% PLA and 75% PLA had similar decomposition behavior, whereas the decomposition temperatures for the blends with 90% PLA decreased with each additional heat cycle. The glass transition and melting temperatures were not impacted by reprocessing, but the crystallinity increased with more heat cycles. The complex viscosity of the reprocessed PLA and PLA/aPHA blends was much lower than for the neat PLA and increasing the number of heat cycles produced smaller reductions in the complex viscosity of 100% PLA and the blend with 90% PLA; no change in complex viscosity was observed for blends with 75% PLA exposed to 2 to 5 heat cycles.... Read More

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Polylactide (PLA) resin composition with improved crystallinity, comprising a first nucleating agent and a second nucleating agent, wherein the second nucleating agent is a bio-based organic compound having a molecular weight of 1000-5000 Da, and the first nucleating agent is selected from the group consisting of uracil, OA1, and OA3. The composition exhibits enhanced crystallization rate and crystallinity degree compared to conventional PLA resins.

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A method for preparing polylactic acid (PLA) polymer with high molecular weight and excellent color characteristics through ring-opening polymerization of lactide using a combination of specific catalysts. The method employs a tin-based catalyst and a phosphinite-based cocatalyst to achieve high molecular weight PLA with improved color stability, overcoming limitations of conventional methods that compromise molecular weight for color quality.

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Polylactic acid (PLA) has garnered significant attention due to its advantages of excellent biodegradability, biocompatibility, and renewable raw materials. This article begins by briefly introducing the research progress in the synthesis and modification of PLA, as well as its specific applications such as medical sutures and textiles, and the pros and cons of PLA itself. It then provides a detailed overview of the direct polymerization methods of PLA, including melt condensation and solution polymerization, and ring-opening polymerization methods such as cationic, anionic, and coordination. The process mechanisms, advantages, and disadvantages of each method are discussed, along with their suitability for practical industrial production and current limitations. Several specific modification methods of PLA are also discussed, such as low-temperature plasma modification and blending modification, highlighting the advantages, disadvantages, and specific research examples. These modifications aim to improve the deficiencies of PLA in areas such as mechanical strength or biological acti... Read More

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Crystallization of poly(l-lactic acid) (PLLA) at temperatures lower and higher than about 100120 C leads to the formation of - and -crystals, respectively. Related to the formation of different crystal polymorphs after crystallization at different temperatures, the small-angle X-ray scattering (SAXS) patterns only show a long-period maximum after crystallization at high temperatures, when -crystals are present. Reason for the absence of a long-period peak after low-temperature crystallization is insufficient density contrast between the formed -crystals and the amorphous phase but not the absence of lamellar stacks and long-range periodicity. This conclusion is based on the observation of a long period after the transformation of -crystals of rather low density into -crystals of higher density, by thermal treatment, while keeping the semicrystalline morphology quasi-unchanged. Long-range periodicity and formation of lamellae in PLLA containing -crystals are ultimately proven by atomic force microscopy, despite a long period is not detected by SAXS.

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A method for improving the melt strength of polylactic acid (PLA) by incorporating small amounts of hydroxy-acid co-monomers with opposite alpha-carbon chirality through ring-opening polymerization. The co-monomers, such as diethylglycolide, are incorporated in amounts of 0.2-10 mol% into the PLA polymer chain, resulting in significant improvements in melt strength, extensional viscosity, and zero-shear viscosity. The resulting copolymers exhibit enhanced melt properties, enabling the production of high-performance PLA materials suitable for various applications, including injection stretch blow molding and extrusion blow molding.

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Polylactic acid (PLA) is a versatile and sustainable polymer used in various applications. This research explores the use of orotic acid (OA) and ethylene bis-stearamide (EBS) as nucleating agents to enhance the quiescent crystallization of PLA within the temperature range of 80 C to 140 C. Different blends were produced via melt processing before analyzing via DSC, XRD, and SEM. Our results show that both nucleating agents significantly accelerated the crystallization process and reduced the incubation time and the crystallization half-time. The most promising results were obtained with 1% EBS at 110 C, achieving the fastest crystallization. The XRD analysis showed that at 80 C, the disordered phase predominated, while more stable phases formed at 110 C and 140 C. Combining the 1% nucleating agent and 110 C promotes densely packed crystalline lamellae. The nucleated PLA exhibited a well-organized spherulitic morphology in agreement with the Avrami modeling of DSC data. Higher nucleating agent concentrations yielded smaller, more evenly distributed crystalline domains. Uti... Read More

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In order to prepare polylactic acid (PLA) foam material with excellent performance by utilizing nitrogen (N 2 ), the crystallization behavior of PLA under N 2 has been studied.

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Abstract This study investigates the effects of molecular weight and crystallinity of polylactic acid (PLA) on the morphology and crystallization behavior of polyhydroxybutyrate (PHB)/PLA blends. Utilizing a solution casting method, we discovered that the molecular characteristics of PLA significantly influence the thermal and structural properties of the blends. The lower molecular weight and amorphous PLA notably broadened the temperature range for PHB's banded spherulite formation, indicating enhanced miscibility. In contrast, semicrystalline PLA variants produced smaller spherulites within large PHB matrices. The high molecular weight PLA had an unusual, relatively low melting point which led to a competition between the molecular weight effect and the supercooling effect regarding the isothermal crystallization kinetics. The blend morphology was observed in thin films in which the usual crystal formation of PHB was severely hindered in the presence of crystalline PLA but could form thin lamellae when the PLA was amorphous. At ultrathin thickness, where crystallization is imposs... Read More

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<title>Abstract</title> To improve the melt strength and crystallisation property of polylactic acid (PLA) for achieving a good foaming performance at high temperatures, linear poly(l-lactide) (PLLA) was mixed with an epoxy chain extender to obtain branched PLLA (bPLLA), which was then blended with poly(d-lactide) (PDLA) to prepare a bPLLA/PDLA blend. The bPLLA/PDLA blend produced stereocomplex (SC) crystals, which increased the melt strength and viscosity of the blend. The synergistic effect of the SC crystals and the branched structure endowed bPLLA/PDLA with high melt strength and processability. In contrast, the nucleation effect of the SC crystals on bPLLA reduced the cell size, resulting in excellent microcellular foamability at the melting temperature. The formation of SC crystals in the blending process increased the crystallinity and enhanced the cell structure. As a result, the compressive strength of bPLLA/PDLA is increased from 0.44 MPa to 0.72 MPa. At 150C, the dimensional deformation rate decreased from 42.5913.13%, whereas the heat resistance increased by &gt; 300%. ... Read More

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A method for producing temperature-resistant PLA cutlery, forks, and spoons that overcomes the limitations of conventional PLA products. The method involves injection molding PLA pellets into a partially crystallized embryo, followed by a controlled pressure and temperature treatment using supercritical carbon dioxide to induce complete crystallization. This process eliminates the need for hot-drying tunnels or water immersion, enabling the production of PLA cutlery with improved strength, temperature resistance, and reduced density. The resulting products exhibit enhanced performance characteristics, including a 65°C temperature resistance and 5-30% reduced density compared to conventional PLA cutlery.

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As semi-crystalline polyester (lactic acid) (PLA) is combined with other reinforcing materials, challenges such as phase separation, environmental pollution, and manufacturing difficulties could hinder the benefits of PLA, including complete biodegradability and strong mechanical properties. In the present investigation, melt blending is utilized to establish a mixture of low- and high-molecular-weight polylactic acids (LPLA and HPLA). The crystallinity, rheology, and mechanical properties of the combination were analyzed using rotational rheometry, differential scanning calorimetry, X-ray diffraction, polarized optical microscopy, scanning electron microscopy, and universal testing equipment. The results demonstrate compatibility between LPLA and HPLA. Moreover, an increase in LPLA concentration leads to a decrease in the crystallization rate, spherulite size, fractional crystallinity, and XRD peak intensity during isothermal crystallization. LPLA acts as a diluent during isothermal crystallization, whereas HPLA functions as a nucleating agent in the non-isothermal crystallization p... Read More

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A biodegradable block copolymer comprising a polylactic acid block and a polyester block, wherein the polyester block is derived from an aliphatic diol with 4 or more carbon atoms and a branched alkyl group, and has a number average molecular weight of 30,000 to 200,000. The block copolymer exhibits excellent biodegradability, hydrolysis resistance, and tensile properties.

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A biodegradable block copolymer comprising a polylactic acid (PLA) block and a polyester block derived from an aliphatic diol with a branched alkyl group and an aliphatic dicarboxylic acid, wherein the polyester block has a number average molecular weight of over 10,000. The copolymer exhibits excellent biodegradability, hydrolysis resistance, and handling properties.

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Composite material for manufacturing barrier layers with improved barrier properties for packaging applications. The composite contains Polyhydroxyalkanoate, polylactic acid, modified layered silicate, polyalkylene carbonate, and an auxiliary agent. The composite is extruded or injection molded into barrier layers for packaging materials like films and boxes. The composite's barrier properties can reduce fluid penetration compared to pure Polyhydroxyalkanoate. The modified layered silicate and polyalkylene carbonate improve barrier properties.

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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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The isothermal crystallization of a poly(l-lactic acid) (PLLA)/poly(d-lactic acid) (PDLA) (50/50) blend, neat PLLA, and neat PDLA, was studied at different crystallization temperatures (110 C, 150 C, 170 and 180 C) for different durations (1-300 min) by means of differential scanning calorimetry (DSC), polarized optical microscope (POM) observations, and time-resolved wide-angle X-ray diffraction (WAXD). The effects of both the isothermal crystallization temperature and the duration of the isothermal crystallization were investigated for the blend specimens fully crystallized at these crystallization temperatures. The formation of homopolymer crystallites (HC) was confirmed at the isothermal crystallization temperature of 170 C, which was previously considered too high for its formation, after 70 min had elapsed from the temperature stabilization. Moreover, the melting temperature of the formed HC was found to be significantly high (Tm = 187.5 C) compared to the one obtained during the nonisothermal DSC measurement of the same specimen of the PLLA/PDLA (50/50) blend, as well as ... Read More

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Poly (lactic acid) (PLA) has gained attention due to its mechanical performance, optical transparency, renewability, biocompatibility and biodegradability in recent past. The slow crystallization kinetics, poor thermal stability, brittleness and process complexity limit its practical applications. Hence, crystallization behavior of PLA was studied enormously in past to improve its performance. Here, in particular, crystallization behavior of poly ( l -lactic acid) (PLLA) and its different forms (in blends, in composites, and after adding nucleating agents, etc.) are described.

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A processed molded article with both high transparency and heat resistance, comprising polylactic acid with a crystal size of 40 nm or less, and a crystal nucleating agent at an amount of 0.5 mass % or less. The polylactic acid contains an L-lactic acid unit at an amount of 99.0 mol % or more or a D-lactic acid unit at an amount of 99.0 mol % or more. The article is produced by impregnating a molded article containing the polylactic acid with carbon dioxide.

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Custom product packaging made from molded bead foam articles formed from polylactic acid (PLA) that can be customized by cutting, heating, boiling, and thermoforming the PLA foam. The PLA foam can be machined, joined, enhanced, and formed in ways superior to or impossible in comparable EPS foam. This allows customization of foam packaging for specific products without waste. The PLA foam can be cut to fit, joined without adhesive by heating surfaces, improved by boiling, and thermoformed. This enables tailored foam packaging for unique products without wasteful cutting or discarding.

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A polylactic acid (PLA) resin composition for producing a foam sheet with improved surface properties, heat insulation, and environmental hygiene. The composition comprises PLA, inorganic particles with a modified surface, and a chain extender, and is processed using a twin-screw extruder at a temperature below the PLA melting point in the presence of a compressible fluid. The foam sheet is produced by vaporizing the compressible fluid from the composition, resulting in a product suitable for food containers and other applications.

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Abstract Polylactic acid (PLA) is a biodegradable polyester, but its low crystallization rate and excessive embrittlement limit its application. Decanedioic acid 1,10bis (2benzoylhydrazide) (TMC300) as an effective nucleating agent of PLA will induce PLA epitaxial crystallization and improve the crystallization rate of PLA. This article studied the promoting behavior of TMC300 with different contents in composite systems on PLA crystallization. The results showed that with the increase of TMC300 content, the crystallinity can be significantly increased, up to 22 times, and t 1/2 significantly decreases. Meanwhile, with the addition of TMC300, the typical spherical crystal morphology of PLA gradually became attached to TMC300 fibrous crystal morphology. In terms of mechanical properties, the tensile strength reached its maximum at 0.5 wt% of TMC300 content, increasing from 60.60 MPa (PLA) to 74.59 MPa (0.5TMC300), an increase of 23.09%. At this time, due to the reduction in spherical crystal size, the elongation at break also increased significantly. However, the thermal sta... Read More

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Polylactic acid (PLA) is one of the most promising biopolymers. PLA shows its versatility in biomedical, additive manufacturing, packaging, and many more applications. Its tailorable properties, biocompatibility, and good processibility have attracted researchers. Over the years, the manufacturing of PLA on an industrial scale has grown considerably. Different researchers have reported various methods for PLA synthesize. Ring-opening polymerization (ROP) is a widely used synthesize and commercial manufacturing method. But ROP is quite an expensive method, so it limits the application of PLA in many products. One of the most unexplored methods for PLA synthesize is azeotropic dehydrative polycondensation or solution polymerization. In this study, all methods are compiled and compared on various aspects.

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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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Biodegradable packaging materials with enhanced gas barrier properties that replace traditional petroleum-based polymers. The materials incorporate biocarbon-based fillers in combination with conventional biodegradable polymers, achieving superior oxygen and water barrier performance. The biocarbon fillers, derived from renewable biomass sources, provide enhanced oxygen barrier properties compared to conventional oxygen scavengers, while maintaining high water barrier performance. The materials exhibit excellent gas barrier properties, making them suitable for applications requiring high oxygen and water barrier performance, such as food packaging and pharmaceutical applications.

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A process for polymerizing lactide into polylactic acid (PLA) that reduces off-spec product, transition time, and Meso-lactide loss. The process involves a two-stage reactor configuration, where the first stage comprises one or more Continuous Stirred Tank Reactors (CSTRs) and the second stage comprises one or more Plug Flow Reactors (PFRs). The D/Meso-lactide feed is introduced after the first reactor stage, allowing for faster grade changes and reduced off-spec product. This configuration also enables the efficient utilization of Meso-lactide, which is typically generated during lactide production.

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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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Tailoring the properties of polylactic acid (PLA) by blending with poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a practical methodology to improve the foaming behavior of PLA. PHBV is biodegradable, nontoxic, biocompatible, and made naturally by bacteria. This study investigates the influence of PLA/PHBV blends on the sorption behavior, crystallization behavior, dynamic mechanical properties, and autoclave foaming. It was shown by atomic force microscopy-infrared (AFM-IR) and dynamic mechanical thermal analysis (DMTA) measurements that PHBV and PLA are immiscible. The results from differential scanning calorimetry (DSC), DMTA, and AFM-IR have been correlated to the foaming behavior of PLA at different PHBV contents (1040%). With increasing PHBV content in the blend, the foam density slightly increased and smaller cell size and an increased foam cell nucleation rate were found. Additionally, the foaming behavior was correlated with thermograms of the foamed samples. Finally, the study showed that PHBV can improve the foam morphology of PLA-based foams.

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A multilayer structure for packaging applications, comprising at least three layers: a base layer of polylactide (PLA), a tie layer of poly(lactide-co-glycolide) (PLGA) with more than 30 mol % lactide, and a barrier layer of PLGA with at most 30 mol % lactide or polyglycolide (PGA). The structure exhibits improved barrier properties, particularly oxygen gas barrier properties, and enhanced lamination properties compared to conventional biopolymer-based multilayer structures.

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A biodegradable film based on polylactides (PLA) and a method for its production by reactive coextrusion. The film, with or without an adhesive layer, is suitable for hot lamination of various materials and production of disposable products. The film's composition includes a combination of amorphous and semi-crystalline PLA layers, with optional addition of thermoplastic copolyamide and epoxy styrene-acrylate copolymer. The reactive coextrusion process enables the formation of branched polymers with improved properties.

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Biodegradable polymer composition comprising a melt blend of poly(3-hydroxypropionate) and poly(lactic acid), where the poly(3-hydroxypropionate) provides nucleation sites that accelerate crystallization of the poly(lactic acid) while maintaining industrial compostability.

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Polylactic acid (PLA) is one of the most promising bioplastic representatives that finds application in many different areas, e.g., as single-use products in the packaging industry, in the form of mulch film for agriculture, or in medical devices. For the development of new areas, especially in terms of long-term applications and the production of recyclable products, the material properties controlled by processing must be known. The state of the art is investigations at the global scale (integral values) without consideration of local structure inhomogeneities and their influence on the material properties. In this work, morphological, thermal, and mechanical properties of injection-molded PLA tensile bars are investigated at different length scales (global and local) as a function of processing parameters. In addition to the processing parameters, such as melt temperature, mold temperature, and cooling time in the mold, the influence of the D-isomer content on the crystallization behavior and the resulting material properties are investigated. The material was found to form crysta... Read More

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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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