Poly Lactic Acid Sheets Research Articles

Polyethylene glycol enhanced antibacterial activity of EDTA and ethyl maltol blended PLA against Staphylococcus aureus for biodegradable active packaging

Poly (lactic acid) (PLA) has limited promise as a bio-based antimicrobial packaging material due to its lack of plasticization, which limits antimicrobial agent release and antimicrobial efficiency. PLA were plasticized with polyethylene glycol (PEG) and blended with ethyl maltol or ethylenediaminetetraacetic acid (EDTA) as antibacterial agents by melt extrusion. The effects of combining PEG, EDTA, and ethyl maltol on sheet properties and antibacterial activity were investigated. Incorporation of ethyl maltol created a dense and smooth homogeneous surface, while EDTA addition caused large pores in the PLA sheet microstructure impacting swelling degree, water solubility and surface hydrophilicity. Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) showed that both ethyl maltol and EDTA addition modified the amorphous and crystalline phases of plasticized PLA. FTIR results suggested interaction between the functional groups of PLA chains, PEG, ethyl maltol or EDTA which affected the glass transition temperature (Tg), degree of crystallinity, and thermal stability of PLA. Adding PEG into PLA-EDTA enhanced antibacterial activity against Gram-positive Staphylococcus aureus (reduction of 1.35 log CFU/mL from the initial inoculum). The higher water solubility of sheets corresponded to a suitable release rate and sufficient amounts of antimicrobial compounds against Staphylococcus aureus. In vitro antifungal testing, PLA-PEG-EDTA sheets did not exhibit a clear zone of inhibition but delayed Penicillium sp. spore formation until day 5 of incubation. PEG plasticized PLA sheets functionalized with ethyl maltol and EDTA showed potential as active biomaterials against food-borne pathogen bacteria Staphylococcus aureus.

Fabrication of hollow microneedles with jagged edges mimicking mosquitoes’ needles using a thermal nanoimprinting method and a mold combining soft and hard materials

In the aim of realizing minimally invasive needles, a hollow microneedle mimicking a mosquito’s proboscis was developed by a thermal nanoimprinting method using the polylactic acid (PLA) of a biodegradable thermoplastic. A mold was proposed and developed, which consisted of a soft polydimethylsiloxane (PDMS) body and a hard acrylic center pillar for creating the hole. Note that, if a mold is made of a single PDMS, the pillar cannot withstand the imprint pressure and tilts. By imprinting the mold against a PLA sheet, a hollow structure with a high aspect ratio of five (i.e., outer/inner diameter: 200/100 μm; height: 1,000 μm) with a sharp tip and jagged edge was successfully achieved.

Effect of Polybutylene Succinate Additive in Polylactic Acid Blend Fibers via a Melt-Blown Process.

This work aimed to study the influence of the polybutylene succinate (PBS) content on the physical, thermal, mechanical, and chemical properties of the obtained polylactic acid (PLA)/PBS composite fibers. PLA/PBS blend fibers were prepared by a simple melt-blown process capable of yielding nanofibers. Morphological analysis revealed that the fiber size was irregular and discontinuous in length. Including PBS affected the fiber size distribution, and the fibers had a smoother surface with increased amounts of added PBS. Differential scanning calorimetry analysis (DSC) revealed that the crystallization temperature of the PLA sheet (105.8 °C) was decreased with increasing PBS addition levels down to 91.7 °C at 10 wt.% PBS. This suggests that the addition of PBS may affect PLA crystallization, which is consistent with the X-ray diffraction analysis that revealed that the crystallinity of PLA (19.2%) was increased with increasing PBS addition up to 28.1% at 10 wt% PBS. Moreover, adding PBS increased the tensile properties while the % elongation at break was significantly decreased.

Fabrication of Biomaterial-Based Triboelectric Nanogenerators: Study of the Relationship between Output Performance and Strain in Dielectric Materials

A triboelectric nanogenerator (TENG) collects thriftless mechanical energy from the surrounding environment and transforms it into electrical energy. This work demonstrated a feasible method for metallizing the polylactic acid (PLA) surface, which was subsequently used as a biomaterial-based TENG electrode material. We demonstrated that microcellular holes and hydrophilic groups (−C-OH and −COOH) were introduced on an alkali-treated PLA sheet surface, subsequently used to absorb Pd2+ by means of covalent bonds, which could serve as catalytic centers for the reduction of Ni2+. Of note, the Ni-layer deposition mechanism represents a typical island-like growth pattern. To be precise, a Ni-coated PLA sheet was fabricated successfully and used as a TENG electrode material. The device had excellent performances, with a maximum output voltage of about 5.1 V, obtained from 6% strain (the corresponding stress is 32.4 kPa) on the PDMS layer. Furthermore, it revealed that under a stress of 0.14–32.4 kPa and strain of 1.3–6%, a linear regression relation existed between the output voltage and the dielectric material strain, and it was found that the density of electrostatic charge formed on the TENG material surface is 4.1 × 106 C/m2. Additionally, the as-fabricated TENG equipment was attached to various positions of the human body and lab to demonstrate the electrical energy obtained from the mechanical movement. It was also used for real-time demonstrations as a self-powered body-tracking device application which may be beneficial in tracking human position counters during self-powered and emergency exercise movements.

Design and fabrication of a biodegradable face shield by using cleaner technologies for the protection of direct splash and airborne pathogens during the COVID-19 pandemic

Due to global supply chain disruptions and high demand for personal protective equipment (PPE), the rapidly expanding COVID-19 crisis left millions of front-line fighters unprotected. The disposal of PPE in the environment caused significant environmental pollution. Hence, indigenous initiatives have been taken to fabricate antiviral and biodegradable face shields with the help of neoteric and cleaner technologies. This paper describes a novel endeavor to design, manufacture, and performance analysis of a face shield made by plastic injection molding and LASER Cutting. Because of the requirement of permanent wear, the face shield's ergonomic design is considered low weight and easy head fixation, alongside high production ability. Here, face shield frames are made with lightweight, biodegradable plastic called Poly Lactic Acid (PLA), whereas an optical grade PLA sheet is used as the visor for better clarity. Visors PLA Sheet is coated with Nano-Silver disinfectant spray to incorporate antiviral properties to the Faceshield. Partially circumferential adjustable elastic straps are used for comfortable head fixation. To evaluate the product, clinical fit tests along with statistical survey were conducted, and the feedback from the end-users on comfort (41% Excellent, 30% Good, 26% Average and 3% Poor), clear view (33% Excellent, 38% Good, 24% Average, and 5% Poor), design features (43% Excellent, 35% Good, and 22% Average), simplicity of installation and disassembly (29% Excellent, 33% Good, and 38% Average), and ease of wearing/removing (45% Excellent, 40% Good, and 15%Average) are encouraging.

Green and Integrated Wearable Electrochemical Sensor for Chloride Detection in Sweat.

Wearable sensors for sweat biomarkers can provide facile analyte capability and monitoring for several diseases. In this work, a green wearable sensor for sweat absorption and chloride sensing is presented. In order to produce a sustainable device, polylactic acid (PLA) was used for both the substrate and the sweat absorption pad fabrication. The sensor material for chloride detection consisted of silver-based reference, working, and counter electrodes obtained from upcycled compact discs. The PLA substrates were prepared by thermal bonding of PLA sheets obtained via a flat die extruder, prototyped in single functional layers via CO2 laser cutting, and bonded via hot-press. The effect of cold plasma treatment on the transparency and bonding strength of PLA sheets was investigated. The PLA membrane, to act as a sweat absorption pad, was directly deposited onto the membrane holder layer by means of an electrolyte-assisted electrospinning technique. The membrane adhesion capacity was investigated by indentation tests in both dry and wet modes. The integrated device made of PLA and silver-based electrodes was used to quantify chloride ions. The calibration tests revealed that the proposed sensor platform could quantify chloride ions in a sensitive and reproducible way. The chloride ions were also quantified in a real sweat sample collected from a healthy volunteer. Therefore, we demonstrated the feasibility of a green and integrated sweat sensor that can be applied directly on human skin to quantify chloride ions.

PLA wear layer based luxury vinyl tiles - Construction and characterization for adhesion strength and wear vs PVC

Polylactic acid (PLA) bio-renewable green polymer films were studied for their use as a drop-in alternate to polyvinyl chloride (PVC) films as the top surface wear layer wear layer for luxury vinyl tiles (LVT). The wear layer is to be adhesively bonded under heat and pressure to an underlying composite layer comprising a thin ∼0.08 mm oily print layer (PL) bonded onto a relatively thick ∼2.5 mm ethyl vinyl acetate (EVA) backing layer (BL). The relative effects of PLA sheet thickness and surface adhesion properties under heat and pressure over time were studied for their influence on key metrics pertaining to tensile strength, elongation at failure, peel strength, wear layer abrasion, and LVT thickness reduction (correlated to print design distortion). Studies were complemented with differential scanning calorimetry (DSC) and PLA surface pretreatments involving Corona plasma discharge, silicone layer coating, and surface roughening. Optimal processing parameters resulted in distortion-free PLA-LVTs (in sizes ranging from 0.1 m × 0.1 m to 0.3 m × 0.3 m) with adhesion peel strengths 1.5–2.1 N/mm (9–12 pli), and wear layer abrasion resistance >2000–4000 taber cycles. This was achieved using 300–500 μm thick crystalline PLA films compressed onto PL-BL composite layers, with platens heated between a narrow range of 90.5–93 °C, under 1 MPa compression, and applied for ∼5–10 min. The onset of unacceptable distortion (>0.2 mm thickness reduction) occurs at/beyond ∼ 95 °C which correlates with onset of melting of the PL coupled with accelerated plastic deformation for the already melting EVA base layer. Effects of PLA wear layer surface pre-treatment reveal that silicone layer did not lead to noticeable changes in peel strength when using a single PLA wear layer. However, close to 100% increase peel strength was noted for PLA-LVTs using a double lap layer of non-silicone coated PLA films. Corona plasma discharge and surface roughened PLA wear layer surprisingly resulted in a significant (∼90%) degradation of peel strength. Related analyses on competing effects and/or influences of above-mentioned key parameters are discussed.

Wetting of Superhydrophobic Polylactic Acid Micropillared Patterns.

Superhydrophobic (SH) polylactic acid (PLA) surfaces were previously produced by various methods and used especially in biomedical applications and oil/water separation processes after 2008. However, the wettability of SH-PLA patterns containing micropillars has not been investigated before. In this study, PLA patterns having regular microstructured pillars with 12 different pillar diameters and pillar-to-pillar distances were prepared by hot pressing pre-flattened PLA sheets onto preformed polydimethylsiloxane (PDMS) soft molds having micro-sized pits. PDMS templates were previously prepared by photolithography using SU-8 molds. Apparent, advancing, and receding water contact angle measurements were carried out on the PLA patterns containing micropillars, and the morphology of the patterns was examined by optical and SEM microscopy. The largest contact angle obtained without the surface modification of the pure PLA pattern was 139°. Then, PLA micropatterns were hydrophobized using three types of silanes via chemical vapor deposition method, and SH-PLA patterns were obtained having θs of up to 167°. It was found that the highest θ values could be obtained when PLA pattern samples were coated with a silane containing a fluorine atom in its chemical structure. Washing and service life stability tests were also performed on the coated pattern samples and all of the silane coatings on the PLA patterns were found to be resistant over a 6 month period.

69 Early Post-operative Mobilization After Treatment of Burn Wounds with Autologous Skin Cell Suspension

IntroductionEarly mobilization has become popular in the literature and the benefits in critically ill patients are well-documented. However, early mobilization in burn care is undefined. Clinical practice guidelines regarding post-operative mobilization (POM) of patients with burn injury, especially after autografting, are limited, resulting in significant practice variance among burn centers. Furthermore, data on mobilization after treatment with autologous skin cell suspension (ASCS), is even more limited, and wider practice variation exists. We hypothesize early POM is safe and does not compromise healing or lead to graft loss.MethodsA retrospective chart review was performed to examine mobility interventions utilized for patients, with mixed partial and full thickness burns, who received ASCS with polylactic acid sheet, with or without meshed splint-thickness skin grafting (STSG), over 6 months. Data included demographics, operative procedure, dressing, post-operative restrictions, POM date by burn therapy, and presence of graft loss ( >25% of grafted area with need for regrafting). The data was analyzed to corelate POM day and graft success. Initially, the authors utilized manufacturer splinting guidelines before becoming more judicious with aggressive early mobilization. Patients at risk of noncompliance and graft sheer were splinted.ResultsFifteen patients were included in the study. In those patients, 25 body areas were grafted with 17 areas receiving ASCS with polylactic acid sheet and 8 areas additionally receiving STSG. On post-operative day (POD) 0, four areas were splinted and no range of motion (ROM) was performed at the joint. The authors splinted 3 out of 4 patients (75%) due to initial manufacturer splinting guidelines. The 4th patient was splinted due to compliance concerns. For the other 21 areas, active ROM, functional mobility and performance of activities of daily living with functional movement was allowed on POD 0. A burn therapist actively treated 64% of patients on POD 0-1 and 100% of patients were treated by POD 2. Minimal patchy graft loss (median 1.5%) was noted in 6 grafted areas including 1 area which crossed a knee despite immobilization. No graft loss was related to POM and was attributed to factors including infection or wound conversion and, by definition, no significant graft loss was found.ConclusionsWhile the sample size is limited, this study suggests early POM of ASCS is safe and does not lead to graft loss. Considerations for mobilization techniques, such as ROM and functional mobility, should include joint involvement, presence of STSG with ASCS overspray, and other patient factors such as health literacy and compliance. Additional prospective studies should be dedicated to the examination of POM to develop clinical practice guidelines which can be widely utilized across burn therapy.

Effect of Tool Rotational Speed and Traverse Speed on Friction Stir Welding of 3D-Printed Polylactic Acid Material

Joining of polymers are usually carried out using adhesives that has a deteriorating quality at elevated working conditions thus limiting its application areas. Friction stir welding (FSW) is a growing solid-state welding technology, with applications including the welding of lightweight materials. FSW was recently introduced for joining thermoplastics materials and found successful. This study attempts in employing FSW to join polylactic acid (PLA)-based 3D printed engineering components and assess the effect of FSW process parameters (tool rotational speed and traverse speed) on the weld property. The present work uses the FSW process to butt weld 5 mm thick 3D printed PLA sheets with taper cylindrical profiled tool. For the experimentation, three different combinations of feed rates and pin rotational speeds are considered. Based on joint efficiency evaluation, it is found that tool rotational speed of 1400 rpm combined with 10 mm/min transverse speed produces the weld with high joint efficiency of 40%.

Improvement in the Performance of the Polylactic Acid Composites by Using Deep Eutectic Solvent Treated Pulp Fiber

As the most favorable alternative to petroleum-based polymers, polylactic acid (PLA) which is the most promising degradable polymer has attracted increasing attention. However, the addition of cellulose to improve its strength often results in a reduction in its toughness. In this work, microscale cellulose is first prepared from pulp fibers by using a deep eutectic solvent, and then is used as the reinforcement of PLA. A microcrystalline cellulose (MCC)/PLA sheet with uniform texture is obtained by the solution mixing, melt blending, hot-pressing and cold-pressing process. The effects of MCC on the crystallization, thermal stability and mechanical properties of the PLA matrix were studied. Upon the addition of 1% cellulose fiber, the tensile strength of MCC/PLA composite sheet increased by 27%, and the elongation at break did not shown an evident decrease. The strength enhancement mechanism was elucidated using scanning electron microscopy, differential scanning calorimetry, and dynamic thermomechanical analysis. The energy dissipation during the deformation process and the compatibility of AMCC and rougher surface of MCC play important role in the strength enhancement. Additionally, UV spectroscopy showed that the composite material absorbed some ultraviolet light. Our results show that the combined use of a deep eutectic solvent and solution mixing is an effective approach for improving the strength of PLA while maintaining its toughness.

Biodegradable cellular polylactic acid ferroelectrets with strong longitudinal and transverse piezoelectricity

Polymers with electrically charged internal air cavities (ferroelectrets) reveal a pronounced piezoelectric response and are regarded as soft electroactive multi-functional materials. This work presents preliminary results on the preparation and piezoelectric effect of ferroelectrets based on the polylactic acid (PLA) polymer. A distinctive feature of the manufactured films is that they are biodegradable. After a microstructure modification of carbon dioxide (CO2) foamed PLA sheets by hot-pressing treatment and corona polarization, these cellular films reveal large piezoelectric d33 and d31 responses in both quasi-static and dynamic modes. For freshly charged films, the maximum quasi-static piezoelectric coefficients are about 600 pC/N (d33) and 44 pC/N (d31) for a relatively thick film of 360 μm and a nominal porosity of about 60%. During the first 20 days after polarization, the piezoelectric activity decreases by half compared to the primary value, but then remains almost unchanged for a long time. Due to an already established inherent biocompatibility of PLA polymers, these eco-friendly ferroelectrets can be potentially used in various biological applications such as biosensors and microenergy harvesters embedded in tissue and artificial muscles.

Twice Stretched Fabrication of Polylactic Acid Microneedle Arrays Using Drawing Lithography

A biodegradable poly-lactic acid (PLA) microneedle array composed of needles with a maximum length of 3 mm and an aspect ratio of up to approximately 18 was fabricated by drawing lithography. In the proposed fabrication method, the melted polymer is stretched twice. The approximate length is set in the first stretch, and the tip is sharpened in the second stretch. In the first stretch, by changing the thickness of the PLA sheet, PLA pillars with various lengths are fabricated. By defining the initial length of the needle, it is possible to set a wide range of aspect ratios and lengths. In the second stretch, it is possible to control the final aspect ratio and length of the needle, as well as the shape of its tip by changing the temperature and stretch speed of the PLA pillars. Finally, it was confirmed that the needle can pierce the surface of artificial skin and porcine skin.

Thermoforming behavior of 3D-printed PLA sheets

Abstract Fused deposition modeling is one of the most well-known additive manufacturing methods. It might be considered the easiest way to produce particle reinforced composites or unreinforced sheets which are biodegradable and used in the packaging industry as well as for custom products. In this study, polylactic acid (PLA) sheets were produced by 3D printing and thermoformed using a lab-scale thermoforming machine. This article aims to determine the deformation behavior of 3d printed PLA sheets during thermoforming. In addition to experimental work, finite element analysis was performed to investigate the prediction capabilities of Mooney-Rivlin and Ogden models for PLA sheets. In addition, the initial thickness of the sheet was optimized using FEA and a python script to obtain final uniform thickness distribution. Thanks to 3D printing’s capability for printing sheets of variable thickness, sheets of variable thickness were printed to verify the material models. As a result, based on the thickness distribution obtained from the experimental study, Mooney-Rivlin and Odgen material models were found to be inadequate for representing the actual deformation behavior of PLA sheets.

Thermoforming behavior of 3D-printed PLA sheets

Abstract Fused deposition modeling is one of the most well-known additive manufacturing methods. It might be considered the easiest way to produce particle reinforced composites or unreinforced sheets which are biodegradable and used in the packaging industry as well as for custom products. In this study, polylactic acid (PLA) sheets were produced by 3D printing and thermoformed using a lab-scale thermoforming machine. This article aims to determine the deformation behavior of 3d printed PLA sheets during thermoforming. In addition to experimental work, finite element analysis was performed to investigate the prediction capabilities of Mooney-Rivlin and Ogden models for PLA sheets. In addition, the initial thickness of the sheet was optimized using FEA and a python script to obtain final uniform thickness distribution. Thanks to 3D printing’s capability for printing sheets of variable thickness, sheets of variable thickness were printed to verify the material models. As a result, based on the thickness distribution obtained from the experimental study, Mooney-Rivlin and Odgen material models were found to be inadequate for representing the actual deformation behavior of PLA sheets.

Fabrication of Microneedle from Stretched Biodegradable Polymer Sheet by 3D Laser Machining

Polylactic acid (PLA) microneedles have been usually fabricated by injection molding. Herein, we consider microneedles that mimic the maxillae of mosquito proboscises, which have sharp tips with jagged harpoon-like protrusions. In case of such microneedles, filling the melting PLA resin up to the tip of the mold trough without burrs is challenging. To address this issue, we have proposed a new microneedle fabrication method in this paper. In this method, the needle with the desired shape was obtained from a PLA sheet by femtosecond laser machining. The needle was turned by 90°, and its tip further cut obliquely with the laser for three-dimensional (3D) sharpening. Tensile and buckling tests were conducted by using a test piece cut out from the PLA sheet. It was experimentally established that the strength and Young’s modulus along the sheet’s stretch direction are higher than those along its perpendicular direction. The 3D sharpened PLA microneedle successfully penetrated an artificial skin made of polydimethylsiloxane. A pair of microneedles were alternately vibrated against each other, mimicking the motion of mosquito two maxillae. With this alternate vibration, the resistance force during insertion was found to be lower compared to that without vibration.

Experimental investigation of friction stir welding of PLA

Friction stir welding (FSW) is a solid-state welding technology which is frequently used for welding of thermoplastic and metallic alloys in the automobile and aerospace industries. Polylactic acid (PLA) is a biodegradable thermoplastic polymer. PLA can replace petroleum-based polymer in many applications if the FSW process can be used for welding of PLA-based engineering components. In the present study, FSW process was carried out to join PLA sheets to investigate the influence of input parameters such as tool speed and transverse speed on the tensile strength of the welded specimens using different pin profiles. The tool speeds of 700, 1400, and 2000 rpm and traverse speeds of 20, 30, and 40 mm/min were selected to perform the welding. The pin profiles such as cylindrical, threaded, and conical pins of the tool were used to study their effect on the joint strength and efficiency. Visual inspection of the welded specimens was carried out to find the defects in welding. The temperature that is induced during welding and the load-displacement behavior of the welded specimens were also studied to understand the welding behavior of biodegradable PLA.

Fabrication of microneedle using poly lactic acid sheets by thermal nanoimprint

A biodegradable PLA (poly-lactic acid) microneedle having high aspect ratio of over 10, e.g., 100 μm in diameter and 1,000 μm (1 mm) in length, was successfully fabricated using thermal nanoimprint method first in the world. First, optimal conditions for fabricating a conical shape, which is assuming a microneedle tip, were preliminarily investigated. Both in vacuum and under atmospheric pressure, pressure of 20 MPa and temperature of 160 °C were necessary. Next, fabrication of a long microneedle was investigated. As compared to the conical shape, higher pressure of 25 MPa and higher temperature of 166 °C were required. By adjusting the releasing temperature around 98 °C, fabrication of a long microneedle having a smooth surface and no deformation, e.g., no bending, was successfully achieved. It was confirmed that the needle surely can puncture the skin and blood vessel of a mouse.

Hydroxylated Natural Rubber Effect on Crystallinity and Mechanical Properties of PLA

This work focuses on the effect of functionality of hydroxylated natural rubber (HNR) and its loading on crystallinity and mechanical properties of polylactic acid (PLA). HNR with hydroxyl groups of 9.09% by mole was prepared from natural rubber latex via epoxidation reaction and then the epoxy rings were cleavaged to produce the hydroxyl groups by using heating at the temperature of 70 °C. HNR4 with the hydroxyl groups of 15.25% by mole was prepared from ONR4 latex with M̅n of 3.94 × 103 g/mol and M̅w of 5.06 × 103 g/mol. PLA was then blended with the obtained HNR or HNR4 with different weight ratios of PLA:HNR = 70:30 and 60:40. It was found that hydroxylated natural rubber increased the crystallinity of molded PLA sheet from 7.54% to 18.20% for molded PLA:HNR = 70:30 sheet, to 25.16% for molded PLA:HNR = 60:40 sheet and to 24.38% for molded PLA:HNR4 = 70:30 sheet. Morphological analyses revealed the appearance of co-continuous phase in the molded PLA:HNR4 = 70:30 clearer than the molded PLA:HNR = 60:40 and molded PLA:HNR = 70:30 sheets. As a result, it clarified that the higher functionality of hydroxyl groups based on lowering the molecular-weight enhanced the compatibility between PLA and HNR. On the other hand, the mechanical properties of PLA:HNR4 = 70:30 were found to be the highest tensile strength (14.46 MPa), elongation at break (13.62%) and modulus (4.10 MPa) though PLA:HNR = 60:40 gave the highest impact strength of 163.98 J/m. This was believed that the hydroxylated natural rubber enhanced the crystallinity and impact strength of PLA through the interface interaction and/or chemical bonds between hydroxyl groups of HNR and carboxyl terminal groups of PLA.

Poly(lactic) acid (PLA) and starch bilayer films, containing cinnamaldehyde, obtained by compression moulding

Bilayer films from thermoplastic starch and cast amorphous PLA were obtained by compression moulding, incorporating or not cinnamaldehyde in the PLA layer. Films were characterized as to their microstructure and barrier, tensile and optical properties, as well as thermal behaviour, X-ray diffraction pattern and FTIR spectra. Bilayers using semicrystalline PLA, instead of starch, were also analysed for comparison purposes. Despite the lower ratio of cast PLA sheet in the bilayer assembly (about 1/3 of the film thickness), a great improvement in tensile and water vapour barrier properties was achieved with respect to the net starch films, the films maintaining high transparency and oxygen permeability as low as starch films. When cinnamaldehyde was included in the cast PLA sheet, films became thinner due to the losses of the volatile active during processing, but the improvement in barrier properties was maintained, with lower mechanical resistance. Thermal analyses revealed diffusion of cinnamaldehyde or low molecular weight compounds from cast PLA layer to the adhered sheets (starch or semicrystalline PLA) which contributed to plasticizing the amorphous regions and affected crystallization pattern of PLA, as also revealed by the X-ray diffraction patterns. The obtained results offer an interesting option to obtain high barrier-highly resistant active films from thermoplastic starch and amorphous PLA, including cinnamaldehyde as active compound.