Thermal and mechanical properties of plasticized poly(L-lactic acid)

Properties and Degradation of Novel Fully Biodegradable PLA/PHB Blends Filled with Keratin

The utilization of keratin waste in new materials formulations can prevent its environmental disposal problem. Here, novel composites based on biodegradable blends consisting of poly(lactic acid) (PLA) and poly(3-hydroxybutyrate) (PHB), and filled with hydrolyzed keratin with loading from 1 to 20 wt % were prepared and their properties were investigated. Mechanical and viscoelastic properties were characterized by tensile test, dynamic mechanical thermal analysis (DMTA) and rheology measurements. The addition of acetyltributyl citrate (ATBC) significantly affected the mechanical properties of the materials. It was found that the filled PLA/PHB/ATBC composite at the highest keratin loading exhibited similar shear moduli compared to the un-plasticized blend as a result of the much stronger interactions between the keratin and polymer matrix compared to composites with lower keratin content. The differences in dynamic moduli for PLA/PHB/ATBC blend filled with keratin depended extensively on the keratin content while loss the factor values progressively decreased with keratin loading. Softening interactions between the keratin and polymer matrix resulted in lower glass transitions temperature and reduced polymer chain mobility. The addition of keratin did not affect the extent of degradation of the PLA/PHB blend during melt blending. Fast hydrolysis at 60 °C was observed for composites with all keratin loadings. The developed keratin-based composites possess properties comparable to commonly used thermoplastics applicable for example as packaging materials.

Thermal and Structural Analysis of Epoxidized Jatropha Oil and Alkaline Treated Kenaf Fiber Reinforced Poly(Lactic Acid) Biocomposites

New environmentally friendly plasticized poly(lactic acid) (PLA) kenaf biocomposites were obtained through a melt blending process from a combination of epoxidized jatropha oil, a type of nonedible vegetable oil material, and renewable plasticizer. The main objective of this study is to investigate the effect of the incorporation of epoxidized jatropha oil (EJO) as a plasticizer and alkaline treatment of kenaf fiber on the thermal properties of PLA/Kenaf/EJO biocomposites. Kenaf fiber was treated with 6% sodium hydroxide (NaOH) solution for 4 h. The thermal properties of the biocomposites were analyzed using a differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It must be highlighted that the addition of EJO resulted in a decrease of glass transition temperature which aided PLA chain mobility in the blend as predicted. TGA demonstrated that the presence of treated kenaf fiber together with EJO in the blends reduced the rate of decomposition of PLA and enhanced the thermal stability of the blend. The treatment showed a rougher surface fiber in scanning electron microscopy (SEM) micrographs and had a greater mechanical locking with matrix, and this was further supported with Fourier-transform infrared spectroscopy (FTIR) analysis. Overall, the increasing content of EJO as a plasticizer has improved the thermal properties of PLA/Kenaf/EJO biocomposites.

Influence of Tea Tree Essential Oil and Poly(ethylene glycol) on Antibacterial and Physicochemical Properties of Polylactide-Based Films

The aim of the study was to establish the influence of poly(ethylene glycol) (PEG) on the properties of potential biodegradable packaging materials with antibacterial properties, based on polylactide (PLA) and tea tree essential oil (TTO). The obtained polymeric films consisted of PLA, a natural biocide, and tea tree essential oil (5–20 wt. %) was prepared with or without an addition of 5 wt. % PEG. The PLA-based materials have been tested, taking into account their morphology, and their thermal, mechanical and antibacterial properties against Staphylococcus aureus and Escherichia coli. It was established that the introduction of a plasticizer into the PLA–TTO systems leads to an increase in tensile strength, resistance to deformation, as well an increased thermal stability, in comparison to films modified using only TTO. The incorporation of 5 wt. % PEG in the PLA solution containing 5 wt. % TTO allowed us to obtain a material exhibiting a satisfactory antibacterial effect on both groups of representative bacteria. The presented results indicated a beneficial effect of PEG on the antibacterial and functional properties of materials with the addition of TTO.

Synergistic effects of sodium adipate/triethylene glycol on the plasticization and retrogradation of corn starch

Starch retrogradation resulted in bad performance and taste of starch products. In this study, the corn starch films modified by sodium adipate and triethylene glycol were prepared by solution casting. The retrogradation of modified starch films were studied by FT-IR, XRD, SEM, tension test and UV-Vis. The results showed that sodium adipate was more effective than triethylene glycol in inhibiting the short-term retrogradation of starch, and triethylene glycol was more effective than sodium adipate in inhibiting the long-term retrogradation of starch. However, the mixture of sodium adipate and triethylene glycol, especially 15% adipic acid and 10% triethylene glycol, showed synergistic effects on the short-term and long-term retrogradation of starch. The starch film with 15% adipic acid and 10% triethylene glycol had the highest elongation at break, the best transmittance, the lowest change rate of elongation at break, and the lowest moisture content among all the recipes.

Effect of Extrusion Screw Speed and Plasticizer Proportions on the Rheological, Thermal, Mechanical, Morphological and Superficial Properties of PLA

One of the critical processing parameters-the speed of the extrusion process for plasticized poly (lactic acid) (PLA)-was investigated in the presence of acetyl tributyl citrate (ATBC) as plasticizer. The mixtures were obtained by varying the content of plasticizer (ATBC, 10-30% by weight), using a twin screw extruder as a processing medium for which a temperature profile with peak was established that ended at 160 °C, two mixing zones and different screw rotation speeds (60 and 150 rpm). To evaluate the thermo-mechanical properties of the blend and hydrophilicity, the miscibility of the plasticizing and PLA matrix, Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), oscillatory rheological analysis, Dynamic Mechanical Analysis (DMA), mechanical analysis, as well as the contact angle were tested. The results derived from the oscillatory rheological analysis had a viscous behavior in the PLA samples with the presence of ATBC; the lower process speed promotes the transitions from viscous to elastic as well as higher values of loss modulus, storage modulus and complex viscosity, which means less loss of molecular weight and lower residual energy in the transition from the viscous state to the elastic state. The mechanical and thermal performance was optimized considering a greater capacity in the energy absorption and integration of the components.

Influence of Hydroxyapatite Surface Functionalization on Thermal and Biological Properties of Poly(l-Lactide)- and Poly(l-Lactide-co-Glycolide)-Based Composites

Novel biocomposites of poly(L-lactide) (PLLA) and poly(l-lactide-co-glycolide) (PLLGA) with 10 wt.% of surface-modified hydroxyapatite particles, designed for applications in bone tissue engineering, are presented in this paper. The surface of hydroxyapatite (HAP) was modified with polyethylene glycol by using l-lysine as a linker molecule. The modification strategy fulfilled two important goals: improvement of the adhesion between the HAP surface and PLLA and PLLGA matrices, and enhancement of the osteological bioactivity of the composites. The surface modifications of HAP were confirmed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), TGA, and elemental composition analysis. The influence of hydroxyapatite surface functionalization on the thermal and in vitro biological properties of PLLA- and PLLGA-based composites was investigated. Due to HAP modification with polyethylene glycol, the glass transition temperature of PLLA was reduced by about 24.5 °C, and melt and cold crystallization abilities were significantly improved. These achievements were scored based on respective shifting of onset of melt and cold crystallization temperatures and 1.6 times higher melt crystallization enthalpy compared with neat PLLA. The results showed that the surface-modified HAP particles were multifunctional and can act as nucleating agents, plasticizers, and bioactive moieties. Moreover, due to the presented surface modification of HAP, the crystallinity degree of PLLA and PLLGA and the polymorphic form of PLLA, the most important factors affecting mechanical properties and degradation behaviors, can be controlled.

Functional Polylactide Blend Films for Controlling Mesenchymal Stem Cell Behaviour

Polymer blending is a suitable physical modification method to create novel properties of different polymers. Blending polylactic acid (PLA) and polyethylene glycol (PEG) produces materials with a wide range of properties. This study was the first to investigate the effect of different isomeric forms of PLA and PEG with terminal amino groups to obtain biocompatible films for human mesenchymal stem cell cultivation. It has been shown by scanning electron microscopy that the surface topology changes to the greatest extent when using films obtained on the basis of poly(d,l-lactide) and PEG with high molecular weights (15,000 g/mol). In order to obtain thin films and rapid evaporation of the solvent, PEG is mixed with PLA and does not form a separate phase and is not further washed out during the incubation in water. The presence of PEG with terminal hydroxyl and amino groups in blend films after incubation in water was proven using Fourier transform infrared (FTIR) spectroscopy. Results of fluorescence microscopy demonstrated that blend films formed on PLA and polyethylene glycol diamine (PEG-NH2) are more suitable for cell spreading and focal contact formation compared to cells cultured on the surface of pure PLA films or films made from PLA and PEG.

Thermal and Morphological Properties of Poly(L-Lactic Acid)/Poly(D-Lactic Acid)-B-Polycaprolactone Diblock Copolymer Blends

Due to the brittle nature of poly(lactic acid) many attempts have been made to flexibilize this polyester for applications such as thin films and foils. However, due to complex phase behavior, many drawbacks for plasticizer and blend components are described. To overcome miscibility, post crystallization and migration issues a principle of click-chemistry was employed to change the molecular characteristics from external to internal plasticization by fixation of a plastisizing unit with help of a stereocomplex crystallization. Hydroxyl terminated polycaprolactone oligomers were used as a macroinitiator for the ring opening polymerization of d-lactide, resulting in blockcopolymers with plasticizing unit polycaprolactone and compatibilizing poly(d-lactic acid)-blocks. The generated block copolymers were blended with a poly(l-lactic acid)-matrix and formed so called stereocomplex crystals. In comparison to unbound polycaprolactone the polycaprolactone blocks show a lower migration tendency regarding a solution test in toluene. Besides that, trapping the plasticizing units via stereocomplex also improves the efficiency of the plasticizer. In comparison to polymer blends with the same amount of non-bonded polycaprolactone oligomers of the same molecular weight, block copolymers with poly(d-lactic acid) and polycaprolactone can shift the glass transition temperature to lower values. This effect can be explained by the modulated crystallization of the polycaprolactone-blocks trapped into the matrix, so that a higher effective amount can interact with the poly(l-lactic acid)-matrix.

Barrier Properties and Characterizations of Poly(lactic Acid)/ZnO Nanocomposites

This study aimed to reinforce the barrier performance (i.e., oxygen-gas and water-vapor permeability) of poly(lactic acid) (PLA)-based films. Acetyltributylcitrate and zinc oxide nanoparticle (nano-ZnO), serving as plasticizer and nanofiller, respectively, were blended into a PLA matrix through a solvent-volatilizing method. The structural, morphological, thermal, and mechanical performances were then studied. Scanning electron microscopic images showed a significant dispersion of nano-ZnO in PLA ternary systems with low nano-ZnO content. The interaction between PLA matrix and ZnO nanoparticles was further analyzed by Fourier-transform infrared spectroscopy. Wide-angle X-ray scattering spectroscopy demonstrated high compatibility between PLA matrix and ZnO nanoparticles. Mechanical property studies revealed good tensile strength and low flexibility. Differential scanning calorimetry curves proved that an amorphous structure mostly existed in PLA ternary systems. The improvements in barrier property and tensile strength indicated that the PLA/nano-ZnO composite films could be used for food packaging application.

Plasticizer Degradation by Marine Bacterial Isolates: A Proteogenomic and Metabolomic Characterization

Many commercial plasticizers are toxic endocrine-disrupting chemicals that are added to plastics during manufacturing and may leach out once they reach the environment. Traditional phthalic acid ester plasticizers (PAEs), such as dibutyl phthalate (DBP) and bis(2-ethyl hexyl) phthalate (DEHP), are now increasingly being replaced with more environmentally friendly alternatives, such as acetyl tributyl citrate (ATBC). While the metabolic pathways for PAE degradation have been established in the terrestrial environment, to our knowledge, the mechanisms for ATBC biodegradation have not been identified previously and plasticizer degradation in the marine environment remains underexplored. From marine plastic debris, we enriched and isolated microbes able to grow using a range of plasticizers and, for the first time, identified the pathways used by two phylogenetically distinct bacteria to degrade three different plasticizers (i.e., DBP, DEHP, and ATBC) via a comprehensive proteogenomic and metabolomic approach. This integrated multi-OMIC study also revealed the different mechanisms used for ester side-chain removal from the different plasticizers (esterases and enzymes involved in the β-oxidation pathway) as well as the molecular response to deal with toxic intermediates, that is, phthalate, and the lower biodegrading potential detected for ATBC than for PAE plasticizers. This study highlights the metabolic potential that exists in the biofilms that colonize plastics-the Plastisphere-to effectively biodegrade plastic additives and flags the inherent importance of microbes in reducing plastic toxicity in the environment.

Two-Way and Multiple-Way Shape Memory Polymers for Soft Robotics: An Overview

Shape memory polymers (SMPs) are smart materials capable of changing their shapes in a predefined manner under a proper applied stimulus and have gained considerable interest in several application fields. Particularly, two-way and multiple-way SMPs offer unique opportunities to realize untethered soft robots with programmable morphology and/or properties, repeatable actuation, and advanced multi-functionalities. This review presents the recent progress of soft robots based on two-way and multiple-way thermo-responsive SMPs. All the building blocks important for the design of such robots, i.e., the base materials, manufacturing processes, working mechanisms, and modeling and simulation tools, are covered. Moreover, examples of real-world applications of soft robots and related actuators, challenges, and future directions are discussed.

4D-printed hybrids with localized shape memory behaviour: Implementation in a functionally graded structure

4D-printed materials are an emerging field of research because the physical structure of these novel materials respond to environmental changes. 3D printing techniques have been employed to print a base material with shape memory properties. Geometrical deformations can be observed once an external stimulus triggers the shape memory effect (SME) integrated into the material. The plasticizing effect is a well-known phenomenon where the microscopic polymer chain movements have been altered and reflected in different shape memory behaviour. It has been suggested that a 4D material with localized actuation behaviour can be fabricated by utilizing functionally graded layers made from different degrees of plasticizing. This study demonstrated that a novel 4D material can be fabricated from material extraction continuous printing technique with different loadings of poly(ethylene glycol) (PEG) plasticize, achieving localized thermal recovery. The results indicate that a plasticized functional layer is an effective technique for creating next generation 4D materials.

Flat Die Extruded Biocompatible Poly(Lactic Acid) (PLA)/Poly(Butylene Succinate) (PBS) Based Films

Biodegradable polymers are promising materials for films and sheets used in many widely diffused applications like packaging, personal care products and sanitary products, where the synergy of high biocompatibility and reduced environmental impact can be particularly significant. Plasticized poly(lactic acid) (PLA)/poly(butylene succinate) (PBS) blend-based films, showing high cytocompatibility and improved flexibility than pure PLA, were prepared by laboratory extrusion and their processability was controlled by the use of a few percent of a commercial melt strength enhancer, based on acrylic copolymers and micro-calcium carbonate. The melt strength enhancer was also found effective in reducing the crystallinity of the films. The process was upscaled by producing flat die extruded films in which elongation at break and tear resistance were improved than pure PLA. The in vitro biocompatibility, investigated through the contact of flat die extruded films with cells, namely, keratinocytes and mesenchymal stromal cells, resulted improved with respect to low density polyethylene (LDPE). Moreover, the PLA-based materials were able to affect immunomodulatory behavior of cells and showed a slight indirect anti-microbial effect. These properties could be exploited in several applications, where the contact with skin and body is relevant.

Enhanced Humid Reliability of Organic Thermoelectrics via Crosslinking with Glycerol

Poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) has shown significant achievements in organic thermoelectrics (TEs) as an alternative for inorganic counterparts. However, PEDOT:PSS films have limited practical applications because their performance is sensitive to humidity. Crosslinking additives are utilized to improve the reliability of PEDOT:PSS film through enhancing hydrophobicity; among these, polyethylene glycol (PEG) is a widely-used additive. However, ether groups in PEG induce water molecules in the film through the hydrogen bond, which deteriorates the TE reliability. Here, we enhance the TE reliability of the PEDOT:PSS film using glycerol as an additive through the crosslinking reaction between the hydroxyl group in glycerol and the sulfonic acid in PEDOT:PSS. The TE reliability (1/Power factor (PF)) of PEG solution-treated PEDOT:PSS film (PEG solution-treated film) was 57% of its initial absolute value (0 h), after 288 h (two weeks) in a humid environment (95% relative humidity, 27 °C temperature). On the other hand, the glycerol solution-treated PEDOT:PSS film (glycerol solution-treated film) exhibited superior TE reliability and preserved 75% of its initial 1/PF. Furthermore, glycerol vapor treatment enabled the film to have stronger TE humid reliability, maintaining 82% of its initial 1/PF, with the same condition. This enhancement is attributed to the increased hydrophobicity and lower oxygen content of the glycerol vapor-treated PEDOT:PSS film (glycerol vapor-treated film), which provides little change in the chemical composition of PEDOT:PSS.

Bio-Inspired, Self-Toughening Polymers Enabled by Plasticizer-Releasing Microcapsules

A new concept for the design of self-toughening thermoplastic polymers is presented. The approach involves the incorporation of plasticizer-filled microcapsules (MCs) in an intrinsically rigid and brittle matrix polymer. The intriguing adaptability that this simple tactic enables is demonstrated with composites composed of a poly(lactic acid) (PLA) matrix and 5-20% w/w poly(urea-formaldehyde) (PUF) MCs that contained hexyl acetate as plasticizer. At low strain (<1.5%), the glassy PLA/MC composites remain rigid, although the intact MCs reduce the Young's modulus and tensile strength by up to 50%. While the neat PLA shows brittle failure at a strain of around 2.5%, the composites yield in this regime, because the MCs rupture and release their plasticizing cargo. This effect leads up to 25-fold increase of the elongation at break and 20-fold increase of the toughness vis-à-vis the neat PLA, while the impact on modulus and ultimate stress is much smaller. Ballistic impact tests show that the self-toughening mechanism also works at much higher strain rates than applied in tensile tests and the operating mechanism is corroborated through systematic thermomechanical studies that involved dynamic mechanical testing and thermal analysis.

Morphology and Properties of a New Biodegradable Material Prepared from Zein and Poly(butylene adipate-terephthalate) by Reactive Blending

In this study, zein, a renewable natural biopolymer from corn, was used to prepare a new biodegradable material with poly(butylene adipate-terephthalate) (PBAT) by reactive blending in the presence of poly(ethylene glycol diglycidyl ether) (PEGDGE). The effects of blending temperature and zein content on the morphology and mechanical and thermal properties of PBAT/zein blends with or without PEGDGE were investigated. Because of the high reactivity of the epoxy group in PEGDGE, the interfacial compatibility between zein and PBAT was improved greatly, and zein exhibited as a spheral phase with smaller size and finer dispersion in the PBAT matrix after the introduction of PEGDGE. Therefore, PEGDGE served as a plasticizer and reactive compatibilizer in the PBAT/zein blending system. Both the tensile strength and elongation at break of the blends with PEGDGE were improved greatly compared with those of the blends without PEGDGE but decreased gradually with the increase of zein content. These findings may provide a feasible way to utilize zein widely, and the new biodegradable blends with excellent stretchability could be used as packing materials in the future.

One step bulk modification of poly(L-lactic acid) composites with functional additives to improve mechanical and biological properties for cardiovascular implant applications

Poly(L-lactic acid) (PLLA) has been widely used as a promising biomaterial in biomedical applications due to its biodegradability and high mechanical strength. However, because of the inherent brittleness, low impact resistance, and weak thermal stability of PLLA, the modification process is usually required to utilize it for biomedical devices. Furthermore, acidic byproducts resulting from the hydrolysis of PLLA after implantation reduce the pH of the surrounding environment and cause inflammatory responses in the implanted area, leading to the failure of their clinical applications. To this end, here, we demonstrate a novel modification process for the PLLA composite with various functional additives, such as cis-aconitic anhydride (AA), triacetin (TA), isosorbide derivative (ISB), and/or Pluronic® F127 (F). The modified PLLA composite with TA and F (PLLA/TF) showed significantly improved elongation at break and Young's modulus and retained tensile strength. Moreover, incorporating magnesium hydroxide (MH) nanoparticles (PLLA/TFMH) significantly reduced acid-induced inflammation responses caused by the acidic degradation products of PLLA. Reduced plasma protein adsorption was observed in the PLLA/TFMH. These results suggest that the one step bulk modification of biodegradable PLLA using TA, F, and MH will have great potential in cardiovascular implant applications.

Thermal, Mechanical, and Rheological Properties of Biocomposites Made of Poly(lactic acid) and Potato Pulp Powder

The thermal, mechanical, and rheological properties of biocomposites of poly(lactic acid) (PLA) with potato pulp powder were investigated in order to (1) quantify how the addition of this filler modifies the structure of the polymeric material and (2) to obtain information on the possible miscibility and compatibility between PLA and the potato pulp. The potato pulp powder utilized is a residue of the processing for the production and extraction of starch. The study was conducted by analyzing the effect of the potato pulp concentration on the thermal, mechanical, and rheological properties of the biocomposites. The results showed that the potato pulp powder does not act as reinforcement but as filler for the PLA polymeric matrix. A progressive decrease in elastic modulus, tensile strength, and elongation at break was observed with increasing the potato pulp percentage. This moderate loss of mechanical properties, however, still meets the technical requirements indicated for the production of rigid packaging items. The incorporation of potato pulp powder to PLA offers the possibility to reduce the cost of the final products and promotes a circular economy approach for the valorization of agro-food waste biomass.

Eco-Friendly Approach and Potential Biodegradable Polymer Matrix for WPC Composite Materials in Outdoor Application

Blends based on high-density polyethylene (HDPE) and poly(lactic) acid (PLA) with different ratios of both polymers were produced: a blend with equal amounts of HDPE and PLA, hence 50 wt.% each, proved to be a useful compromise, allowing a high amount of bioderived charge without this being too detrimental for mechanical properties and considering its possibility to biodegradation behaviour in outdoor application. In this way, an optimal blend suitable for producing a composite with cellulosic fillers is proposed. In the selected polymer blend, wood flour (WF) was added as a natural filler in the proportion of 20, 30, and 40 wt.%, considering as 100 the weight of the polymer blend matrix. There are two compatibilizers to modify both HDPE-PLA blend and wood-flour/polymer interfaces, i.e., polyethylene-grafted maleic anhydride and a random copolymer of ethylene and glycidyl methacrylate. The most suitable percentage of compatibilizer for HDPE-PLA blends appears to be 3 wt.%, which was selected also for use with wood flour. In order to evaluate properties of blends and composites tensile tests, scanning electron microscopy, differential scanning calorimetry, thermogravimetric analyses, and infrared spectroscopy have been performed. Wood flour seems to affect heavy blend behaviour in process production of material suggesting that future studies are needed to reduce defectiveness.

Optimization of Thermoplastic Blend Matrix HDPE/PLA with Different Types and Levels of Coupling Agents

High-density polyethylene (HDPE) and poly(lactic) acid (PLA) blends with different ratios of both polymers, namely, 30:70, 50:50, and 70:30, were produced. Polyethylene-grafted maleic anhydride and a random copolymer of ethylene and glycidyl methacrylate were also considered as compatibilizers to modify HDPE/PLA optimal blends and were added in the amounts of 1, 3, and 5 wt.%. Different properties of the blends were evaluated by performing tensile tests and scanning electron microscopy to analyze blend and interfaces morphology. Moreover, thermomechanical analysis through differential scanning calorimetry, thermo-gravimetric analysis, and infrared spectroscopy were also performed. The blend containing equal amounts of HDPE and PLA seemed to present a good balance between amount of bio-derived charge and acceptable mechanical properties. This suggests that these blends have a good potential for the production of composites with lingo-cellulosic fillers.

Preparation of poly(L-lactide)/poly(ethylene glycol)/organo-modified montmorillonite nanocomposites via melt intercalation under continuous elongation flow

An innovative eccentric rotor extruder (ERE), which can generate continuous elongation flow, was used to prepare the poly(L-lactide) (PLLA)/poly(ethylene glycol) (PEG)/organo-modified montmorillonite (OMMT) nanocomposites. The morphology was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), and showed that the OMMT nanoparticles were uniformly dispersed in the matrix and mainly existed in intercalation mode. The influence of OMMT on the rheological behavior of plasticized PLLA was investigated by dynamic rheological measurements, showing greater improvement of rheological properties compared to that of PLLA/PEG blend. The crystallization behavior and crystalline structures were studied by differential scanning calorimetry (DSC) and XRD, respectively, and showed that the presence of OMMT further speeds up the crystallization rate of plasticized PLLA. However, the crystallization rate and crystallinity had a slight downward trend at high OMMT content because of the inhibition effect of the OMMT percolation network structure. Polarizing optical microscopy (POM) was further carried out and proved that the OMMT nanoparticles as a heterogeneous nucleating agent can increase the spherulite growth rate and nucleation density. The thermal stability was investigated by thermogravimetric analysis and indicated that the addition of OMMT at low concentration can improve the thermal stability of plasticized PLLA more effectively.