Effect of water on the oxygen barrier properties of poly(ethylene terephthalate) and polylactide films

The aim of this work was to study the variations in the oxygen diffusion, solubility, and permeability coefficients of polylactide (PLA) films at different temperatures (5, 23, and 40°C) and water activities (0–0.9). The results were compared with the oxygen diffusion, solubility, and permeability coefficients obtained for poly(ethylene terephthalate) (PET) films under the same experimental conditions. The water sorption isotherm for PLA films was also determined. Diffusion coefficients were determined with the half‐sorption time method. Also, a consistency test for continuous‐flow permeability experimental data was run to obtain the diffusion coefficient with the lowest experimental error and to confirm that oxygen underwent Fickian diffusion in the PLA films. The permeability coefficients were obtained from steady‐state permeability experiments. The results indicated that the PLA films absorbed very low amounts of water, and no significant variation of the absorbed water with the temperature was found. The oxygen permeability coefficients obtained for PLA films (2–12 × 10^?18 kg m/m² s Pa) were higher than those obtained for PET films (1–6 × 10^?19 kg m/m² s Pa) at different temperatures and water activities. Moreover, the permeability coefficients for PLA and PET films did not change significantly with changes in the water activity at temperatures lower than 23°C. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1790–1803, 2004     

Characterization of polymeric LB thin films for sensor applications

The Quartz Crystal Microbalance (QCM) system is utilized to investigate the relationship between mass uptake and associated swelling for Langmuir‐Blodgett (LB) organic thin films obtained from pyrene end‐capped polystyrene (PS). The study was carried out using three different molecular weights of polymeric chains. The changes in resonance frequency associated with mass changes can be attributed to the swelling behavior of polymeric thin films during vapor absorption. This swelling is due to the capturing of organic vapor molecules in the sensor environment. To quantify real‐time QCM data for swelling, early‐time Fick's law of diffusion was adopted to fit the results, and a good linear relationship was observed between the mass uptake and square root of the swelling time. The diffusion coefficients for swelling were thus obtained from the slopes of the fitting curves and was found to be correlation with the amount of organic vapor content in the cell. It was also observed that diffusion of the organic vapor into higher molecular weight polystyrene thin films are much faster than low molecular weight ones in sensor applications. Diffusion coefficients were found to be 0.2–3.0 × 10^?16, 5.0–13 × 10^?16, and 1.0–1.6 × 10^?15 cm²/s for PS1, PS2, and PS3 LB thin films, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Improvement of the photostabilization of PVC films in the presence of 2N‐salicylidene‐5‐(substituted)‐1,3, 4‐thiadiazole

The photostabilization of poly(vinyl chloride) (PVC) films by 2N‐salicylidene‐5‐(substituted)‐1,3,4‐thiadiazole compounds was investigated. The PVC films containing concentration of complexes 0.5% by weight were produced by the casting method from tetrahydrofuran (THF) solvent. The photostabilization activities of these compounds were determined by monitoring the carbonyl, polyene, and hydroxyl indices with irradiation time. The changes in viscosity average molecular weight of PVC with irradiation time were also tracked (using THF as a solvent). The quantum yield of the chain scission (ϕ_cs) of these complexes in PVC films was evaluated and found to range between 4.72 × 10⁻⁸ and 8.99 × 10⁻⁸. Results obtained showed that the rate of photostabilization of PVC in the presence of the additive followed the trend: According to the experimental results obtained, several mechanisms were suggested depending on the structure of the additive. Among them, UV absorption, peroxide decomposer, and radical scavenger for photostabilizer mechanisms were suggested. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Water sorption and water‐resistance properties of poly(vinyl alcohol)/clay nanocomposite films: Effects of chemical structure and morphology

A series of poly(vinyl alcohol)/sodium montmorillonite (PVA/NaMMT) nanocomposite films were prepared via a solution method, and their water sorption and water‐resistant properties were investigated as a function of clay content. The water sorption and water resistance properties were strongly dependent on the chemical structure and film morphology originating from the NaMMT content. The water diffusion coefficient and water uptake of the PVA/NaMMT nanocomposite films were obtained by best fits to a Fickian diffusion model. The diffusion coefficient and water uptake in the PVA/NaMMT nanocomposite films varied between 8.16 × 10⁻¹⁰ and 3.60 × 10⁻¹⁰ cm² s⁻¹ and 35.6 and 29.9 wt%, respectively. Both the diffusion coefficient and water uptake decreased as the content of NaMMT in pure PVA was increased. Additionally, the water resistance pressure (mm) of the PVA/NaMMT nanocomposite films increased with increasing NaMMT content. Contact angle analyses showed that the chemical affinity to water and the surface energy of the nanocomposite films decreased with increasing NaMMT content. Furthermore, the well‐dispersed and exfoliated structure in the nanocomposite films not only induced an increased tortuous path for water molecules to pass through, but also increased the molecular order. However, to enhance the water sorption properties and water resistance of hydrophilic PVA, further studies to increase the dispersion of clay particles and ensure desired morphological qualities such as crystallinity and molecular packing order in the PVA/clay nanocomposite films are required. POLYM. COMPOS., 36:660–667, 2015. © 2014 Society of Plastics Engineers     

Effect of multistratification and film depth on the visualized dynamic sorption behavior of perylene in cellulose acetate films by a confocal laser scanning microscope technique

The sorption behavior of a fluorescent reagent into a polymer film was visualized by confocal laser scanning microscopy (CLSM), and the effects of the additives, film types, and film depth on the diffusion coefficient (D) of the fluorescence reagent were examined. Perylene and cellulose acetate (CA) were used as a fluorescent reagent and a polymer material, respectively. Perylene dissolved in the additives triethylene glycol diacetate (TEGDA) and glycerol triacetate (GTA) was added to the CA film. Then, the evaluation of two types of CA films, a closed‐system cellulose acetate (CCA) sample and an open‐system cellulose acetate (OCA) sample, was conducted. At optimized CLSM conditions (with a scanning range at a 20‐μm depth from the CA film surface with 1‐μm intervals and a scanning speed of 1 fps), the sorption of perylene at the inner CA film was determined. The D values of perylene in the CA film were calculated pursuant to Fick's second law. Higher D values of perylene mixed with TEGDA versus those of perylene mixed with GTA were commonly obtained for the CCA sample (TEGDA: 8.9 × 10⁻¹⁵ m²/s > GTA: 1.7 × 10⁻¹⁵ m²/s) and the OCA sample (TEGDA: 11 × 10⁻¹⁵ m²/s > GTA: 3.3 × 10⁻¹⁵ m²/s) because of the higher chemical affinity of TEGDA with perylene than that of GTA. Perylene indicated a higher D value and was homogeneously distributed in the case of the OCA sample; we found that diffusivity and distribution of perylene in CA film were largely affected by the multistratification treatment. We also proved that the deeper the film depth was, the lower the diffusivity of perylene was, regardless of the types of additives and films. The factors considered for the film‐depth dependence of D were a gradual increase in the diffusion pathway for perylene caused by additive diffusion and the concentration dependence of the perylene D. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Permeability and partition coefficient of aqueous sodium chloride in soft contact lenses

Transport of physiologic saline through soft contact lenses is important to on‐eye behavior. Using a specially designed Stokes‐diaphragm cell, we measure aqueous NaCl permeabilities through commercial soft contact lenses at 35°C. The permeabilities increase exponentially with the water content of the lenses spanning a range from 10⁻⁷ to 10⁻⁵ cm²/s. Equilibrium partition coefficients are obtained by the back‐extraction of lenses initially immersed in 1M aqueous NaCl. Partition coefficients also increase with lens water content but over a smaller range, from 0.1 to 0.7. Because the partition coefficient values are smaller than the water content of the lenses, ideal theory is not followed. Donnan exclusion, bound water, and excluded volume are proposed explanations. The diffusion coefficients of aqueous NaCl through soft contact lenses increase with increasing lens water content following free‐volume theory. Aqueous NaCl diffusivities in the lower water‐content lenses are smaller than the diffusion coefficient of NaCl in water by factors up to 100 indicating very tortuous diffusion paths. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Permeability of ethanol solution through poly(lactic acid) film

The permeation properties of ethanol solution through poly(lactic acid) (PLA) films were investigated. The total flux of ethanol solution through PLA films was strongly depended on the flux of water. In addition, the diffusion coefficient of water was 1000 times higher than that of ethanol, and decreased with increasing feed concentration. After the permeation measurement, crystallization (X_C‐DSC = 1–2%) was observed. However, the crystallinity was not dependent on the feed concentration. On the other hand, the mole ratio of ethanol and water molecules in the PLA film strongly depended on the feed concentration. Based on the results, we concluded that the interaction with ethanol molecules caused the decrease in diffusion coefficient of water in PLA film. Thus, the permeation mechanism of the ethanol solution to the PLA film was investigated in detail. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42031.     

Water sorption behaviors of the BPDA‐based polyimide films depending upon the structural isomers of diamine

For the biphenyltetracarboxylic dianhydride (BPDA)‐based polyimide thin films, the water sorption behaviors were gravimetrically investigated by using a thin film diffusion analyzer. The water sorption behaviors of the polyimide thin films are quite different and strongly dependent upon the sort of polyimide. The diffusion coefficients of the polyimide thin films vary in the range of 1.6 × 10⁻¹⁰ to 12.4 × 10⁻¹⁰cm²/s and the water uptakes vary from 1.52 to 5.25 wt %. Both the diffusion coefficient and water uptake of the polyimide thin films are in the increasing order: BPDA‐pPDA < BPDA‐p,p′ODA < BPDA‐p,m′ODA < BPDA‐mPDA ∼ BPDA‐p,p′DDS < BPDA‐m,m′DDS. Specifically, the polyimide films with para‐oriented linkages in backbone structure showed relatively lower diffusion coefficient and water uptake than the corresponding polyimide films with meta‐oriented linkages because of the well‐developed crystalline structure and good intermolecular chain ordering. In addition, the polyimide thin films having higher chain order showed relatively lower diffusion coefficient and water uptake. The crystallinity and intermolecular chain ordering in the morphological structure are critical parameters in controlling the water sorption behaviors of the polyimide thin films. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2121–2127, 2001     

Biodegradable porous polylactic acid film as a separator for supercapacitors

A porous polylactic acid (PLA) film was investigated as a separator for supercapacitors (SCs) and compared with commercial separators, for example, NKK-MPF30AC and Celgard 2400. The porous PLA film was fabricated via a facile phase inversion method, and the cross-sectional scanning electron microscope images of the PLA separator film exhibited highly porous interconnected morphology for ion diffusion. The surface modification of separators was performed by radio frequency (RF) air plasma to improve wettability. The plasma modification enhanced the water uptake and swelling properties of the separators and decreased the water contact angles of PLA and Celgard 2400 films. The mechanical and dielectric properties of separators were also studied. The ionic conductivities of RF-PLA in 1 M H₂SO₄ and 1 M Na₂SO₄ were found to be 1.1 × 10⁻¹ S/cm and 0.6 × 10⁻² S/cm at room temperature, respectively. The electrochemical impedance spectroscopy of the RF-PLA SCs showed the lowest solution resistance and internal resistance.     

Characterization and electrical conductivity of poly(ethylene glycol)/polyacrylonitrile/multiwalled carbon nanotube composites

Poly(Lactic acid) (PLA)‐layered silicate nanocomposite films were prepared by solvent casting method. The films were irradiated with Co⁶⁰ radiation facility at dose of 30 kGy. The effect of γ irradiation on mechanical properties of the neat PLA and nanocomposites was evaluated by data obtained from tensile testing measurements. The tensile strength of the irradiated PLA films increased with addition of 1 wt % triallyl cyanurate indicating crosslink formation. Significant ductile behavior was observed in the PLA nanocomposites containing 4 pph of nanoclay. Incorporation of nanoclay particles in the PLA matrix stimulated crystal growth as it was studied by differential scanning calorimetry. The morphology of the nanocomposites characterized by transmission electron microscopy and X‐ray diffraction revealed an exfoliated morphology in the PLA nanocomposite films containing 4 pph of nanoclay. Only very small changes were observed in the chemical structure of the irradiated samples as it was investigated by Fourier transform infrared spectroscopy. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Nonlinear optical properties of poly‐ortho‐toluidine films implantated by N+ ions with different energy

This article reports experimental work on the effect of N⁺ ion implantation on third‐order nonlinear optical properties of POT films. Using K₂Cr₂O₇ as oxidizing agent, poly‐ortho‐toluidine (POT) was synthesized in 1 M hydrochloric. The POT films were prepared by spin‐coating method and then implantated by N⁺ ions (15–30 KeV) at a dose 1.9 × 10¹⁶ ions/cm². The films were characterized by FT‐IR spectroscopy, visible spectroscopy and SEM, their third‐order nonlinear optical susceptibility (χ⁽³⁾) were also examined by a degenerate four‐wave mixing (DFWM) system at 532nm. Compared to pristine POT films, the optical band gap obtained from visible spectra decreased from 3.58 to 3.48 eV when the energy was 30 KeV. Also, The χ⁽³⁾ value of implantated POT films increased from 3.31 × 10⁻¹⁰ esu to 4.04 × 10⁻⁹ esu when the implantated energy was 25 KeV. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Understanding the oxygen barrier property of highly transparent poly(lactic acid)/benzoxazine composite film by analyzing the UV-shielding performance

This work reports a new composite film from poly(lactic acid) (PLA) and benzoxazine (BOZ). Introduction of BOZ to PLA simultaneously improves the ultraviolet (UV)-shielding and oxygen barrier properties, which show strong dependence on the content of BOZ. The PLA film demonstrates almost no UV-shielding capacity, but the PLA/BOZ composite film can reach UV-shielding capacity of 98.3% at 350 nm. The corresponding average oxygen permeability coefficient of the composite film is as low as 1.168 × 10⁻¹⁸ m³ m m⁻² s⁻¹ Pa⁻¹, which is significantly lower than that of PLA (5.540 × 10⁻¹⁷ m³ m m⁻² s⁻¹ Pa⁻¹). Meanwhile, the composite film retains visible transparency ≥90.0% at 550 nm. The relationship and its implication between the oxygen barrier performance and UV-shielding capacity are discussed, which propose new guidelines for the development of high barrier PLA film. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47510.     

Characterization and determination of swelling and diffusion characteristics of poly(n‐vinyl‐2‐pyrrolidone) hydrogels in water

Hydrogels in the form of rods with varying crosslink densities and three‐dimensional network structures were prepared from Poly(N‐vinyl‐2‐pyrrolidone) (PVP)/water and PVP/water/persulfate systems by irradiation with γ rays at ambient temperature. Average molecular weights between crosslinks, percent swelling, swelling equilibrium values, diffusion/swelling characteristics (i.e., the structure of network constant, the type of diffusion, the initial swelling rate, swelling rate constant), and equilibrium water content were evaluated for both hydrogel systems. Water diffusion to the hydrogel is a non‐Fickian type diffusion and diffusion coefficients vary from 6.56 × 10⁻⁷ to 2.51 × 10⁻⁷cm²min⁻¹ for PVP and 6.09 × 10⁻⁷ to 2.14 × 10⁻⁷ cm²min⁻¹ for PVP/persulfate hydrogel systems. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 994–1000, 2000     

Optical percolation and oxygen diffusion in poly(divinylbenzene) doped poly(methyl methacrylate) latex flms

A simple fluorescence technique is proposed for the measurement of the diffusion coefficient of oxygen into poly(methyl methacrylate) (PMMA) latex‐poly(divinylbenzene) (PDVB) composite films. Percolation model was used by using photon transmission (PT) technique to interpret the distribution of PDVB particles in PMMA lattice. Optical results were interpreted according to site percolation theory. The optical percolation threshold value and critical exponent were calculated as, R_c = 0.03 and, β = 0.34, respectively. PT measurements were performed for eight different PDVB content (0, 1.5, 3, 5, 10, 20, 40, and 60) wt%. Pyrene (P) functionalized PDVB cross‐linked spherical microspheres with diameters of 2.5 μm were synthesized by using precipitation polymerization technique followed by click coupling reaction. The diameter of the PMMA particles prepared by emulsion polymerization was in the range of 0.5–0.7 μm. PMMA/PDVB composite films were then prepared by physically blending of PMMA latex with PDVB microspheres at various compositions. The steady‐state fluorescence method was used to monitor oxygen diffusion into these (0, 5, 10, 20, and 40 wt%) latex films. Diffusion coefficients, D, of oxygen were determined by the fluorescence quenching method by assuming Fickian transport and were found to be increased from 1.8 × 10⁻¹¹ to 36.6 × 10⁻¹¹ cm² s⁻¹ with increasing PDVB content. This increase in D values was explained with formation of microvoids in the film by using PT technique. POLYM. COMPOS., 2013. © 2012 Society of Plastics Engineers     

Preparation of oxygen gas barrier poly(ethylene terephthalate) films by deposition of silicon oxide films plasma‐polymerized from a mixture of tetramethoxysilane and oxygen

To prepare silicon oxide (SiOx)‐deposited poly(ethylene terephthalate) films with high oxygen gas barrier capability, SiOx deposition by plasma polymerization has been investigated from the viewpoint of chemical composition. Tetramethoxysilane (TMOS) is suitable as a starting material for the synthesis of the SiOx films. The SiOx deposition under self‐bias, where the etching action occurs around an electrode surface, is effective in eliminating carbonaceous compounds from the deposited SiOx films. There is no difference in the chemical composition between the SiOx films deposited under self‐bias and under no self‐bias. The SiOx films are composed of a main component of Si O Si networks and a minor component of carbonized carbons. The SiOx films deposited under no self‐bias from the TMOS/O₂ mixture show good oxygen gas barrier capability, but the SiOx films deposited under the self‐bias show poor capability. The minimum oxygen permeation rate for poly(ethylene terephthalate) films deposited SiOx film is 0.10 cm³ m⁻² day⁻¹ atm⁻¹, which corresponds to an oxygen permeability coefficient of 1.4 × 10⁻¹⁷ cm³‐cm cm⁻² s⁻¹ cm⁻¹ Hg for the SiOx film itself. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2091–2100, 1999     

Direct current electrical characterization of plasma polymerized pyrrole-N,N,3,5 tetramethylaniline bilayer thin films

The direct current conduction mechanism in plasma polymerized pyrrole-N,N,3,5 tetramethylaniline (PPPy-PPTMA) bilayer thin films has been discussed in this article. A parallel plate capacitively coupled glow discharge reactor was used to deposit PPPy, PPTMA, and PPPy-PPTMA thin films at room temperature onto glass substrates. The Fourier Transform Infrared analyses showed that the PPPy-PPTMA bilayer thin films contained the structural characteristics of both the PPPy and PPTMA. The current density-voltage characteristics of PPPy-PPTMA bilayer thin films of different deposition time-ratios indicated an increase in electrical conductivity as the proportion of PPTMA was increased in the bilayer films. It is also observed that the conductivity of the bilayer thin film is reduced compared with its component thin films. It is seen that in the low voltage region the current conduction obeys Ohm's law, while the charge transport phenomenon appears to be the space charge limited conduction in the higher voltage region. The mobility of the charges, the free charge carrier density, and the permittivity of the PPPy, PPTMA and PPPy-PPTMA bilayer thin films have been calculated. The permittivity for PPPy, PPTMA and PPPy-PPTMA bilayer thin films were found to be 1.07 × 10⁻¹⁰, 2.2 × 10⁻¹¹, and 1.26 × 10⁻¹⁰ C² N⁻¹ m⁻², respectively; the free charge carrier density were (3.56 ± 0.01) × 10²², 2 × 10²¹ and (5.19 ± 0.02) × 10²² m⁻³ respectively; and the mobility of the charges were found to be (4.4 ± 0.01) × 10⁻¹⁹, 1.3 × 10⁻¹³ and (2.1 ± 0.01) × 10⁻¹⁹ m² V⁻¹ s⁻¹ respectively. PACS: 72.80.Le, 73.21.Ac, 73.40.Rw, 73.50.Gr, 73.61.Ph. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Lipase‐catalysed synthesis of natural ethanol esters: effect of water removal on enzyme reutilisation

Lipase‐catalysed synthesis of ethanol esters using natural substrates is presented. Initial substrate concentrations, optimised through an experimental design, were 0.8 mol dm⁻³ lauric acid and 0.58 mol dm⁻³ ethanol, with an initial esterification rate (r₀) of 17.13 mmol dm⁻³ min⁻¹. Two different water removal systems were compared: a cooling exchanger in the reactor headspace and a vacuum‐based system. The best results were obtained with the second system. After six consecutive operations with the same enzyme, no loss of activity was observed. The yields obtained in all the runs were greater than 90%. Using the same approach three different natural esters (ethyl laureate, ethyl myristate and ethyl palmitate) were synthesised at 0.9 dm³ scale. Similar results were obtained in all three cases, with chemical yields always being greater than 90%. © 2000 Society of Chemical Industry     

Synthesis and properties of polyamides based on 5,5′‐bis[4‐(4‐aminophenoxy)phenyl]‐hexahydro‐4,7‐methanoindan

A new diamine 5,5′‐bis[4‐(4‐aminophenoxy)phenyl]‐hexahydro‐4,7‐methanoindan ( 3 ) was prepared through the nucleophilic displacement of 5,5′‐bis(4‐hydroxylphenyl)‐hexahydro‐4,7‐methanoindan ( 1 ) with p‐halonitrobenzene in the presence of K₂CO₃ in N,N‐dimethylformamide (DMF), followed by catalytic reduction with hydrazine and Pd/C in ethanol. A series of new polyamides were synthesized by the direct polycondensation of diamine 3 with various aromatic dicarboxylic acids. The polymers were obtained in quantitative yields with inherent viscosities of 0.76–1.02 dl g⁻¹. All the polymers were soluble in aprotic dipolar solvents such as N,N‐dimethylacetamide (DMAc) and N‐methyl‐2‐pyrrolidone (NMP), and could be solution cast into transparent, flexible and tough films. The glass transition temperatures of the polyamides were in the range 245–282 °C; their 10% weight loss temperatures were above 468 °C in nitrogen and above 465 °C in air. © 2000 Society of Chemical Industry     

Selective recognition of chloroacetic acids by imprinted polyaniline film

A novel conductive imprinted polyaniline (PAN) film is prepared by adding template during the PAN film preparation. Monochloroacetic acid (MCA) and trichloroacetic acid (TCA) were used as templates. The conductivity of imprinted PAN films was measured by the four‐point probe method. The conductivity changes of imprinted PAN films were compared to reference PAN reflecting the MCA and TCA specific sites on the surface of PAN films. The conductivities were linearly dependent on the template concentrations, and linear calibration curves were obtained in the range 1–30 and 1–40 ppm of the MCA and TCA, respectively. Excellent method reproducibility (standard deviation 0.04 S/cm⁻¹) was observed for the determination of 15 ppm MCA. The effect of various factors on preparation, properties, and recognition effects of the imprinted PAN films was investigated. The best electrical and mechanical properties were obtained with 7 × 10⁻⁴ mmol MCA as a template and doping agent. The measurements are carried out under room temperature, and the maximum conductivities are reached after about 10 and 20 min for reference and imprinted PAN film, respectively. Selectivity experiments were carried out with standard MCA, TCA, and five analogs (dichloro‐, dibromo‐, and monobromoacetic acid) in water. The results exhibited a good selectivity for the templates compared to structurally related compounds. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation,characterization, and biodegradability of renewable resource‐based composites from recycled polylactide bioplastic and sisal fibers

The biodegradability, morphology, and mechanical thermal properties of composite materials composed of polylactide (PLA) and sisal fibers (SFs) were evaluated. Composites containing acrylic acid‐grafted PLA (PLA‐g‐AA/SF) exhibited noticeably superior mechanical properties because of greater compatibility between the two components. The dispersion of SF in the PLA‐g‐AA matrix was highly homogeneous as a result of ester formation and the consequent creation of branched and crosslinked macromolecules between the carboxyl groups of PLA‐g‐AA and hydroxyl groups in SF. Furthermore, with a lower melt temperature, the PLA‐g‐AA/SF composite is more readily processed than PLA/SF. Both composites were buried in soil to assess biodegradability. Both the PLA and the PLA‐g‐AA/SF composite films were eventually completely degraded, and severe disruption of film structure was observed after 6–10 weeks of incubation. Although the degree of weight loss after burial indicated that both materials were biodegradable even with high levels of SF, the higher water resistance of PLA‐g‐AA/SF films indicates that they were more biodegradable than those made of PLA. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011