Viscoelastic,thermal and environmental characteristics of poly(lactic acid), linear low-density polyethylene and low-density polyethylene ternary blends and composites

Poly(lactic acid) (PLA)/(linear low-density polyethylene (LLDPE)–low-density polyethylene (LDPE)) PLA/(LLDPE-LDPE) ternary blends were prepared and characterized as function of the PLA content. (50/50) PLA/(LLDPE–LDPE) blend was also compatibilized using maleic anhydride grafted low-density polyethylene (PE-g-MA) incorporated with a concentration of 5 wt.%. PLA/(LLDPE–LDPE) blend composites have been prepared by dispersing 5 wt.% of an organophilic montmorillonite (Org-MMT), added according to two different mixing methods. These materials were subjected to several investigations such as X-rays diffraction (XRD), dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry, and environmental tests. In the PLA glassy region, DMTA results showed that the storage modulus of PLA/(LLDPE–LDPE) blends decreases upon decreasing the PLA content. When PE-g-MA and Org-MMT were added, PLA exhibited a noticeable increase in the storage modulus across the glass transition region due the interface reinforcement and the enhancement of the blends stiffness. The decrease in the magnitude of the PLA tan δ peak was attributed to the decrease in the molecular mobility that could result from the increase in the interfacial resistance. XRD analysis showed that the method of dispersion of the nanoclay controls the final structural properties of the composites. (50/50) PLA/(LLDPE-LDPE) blend and composites revealed a satisfactory aptitude to biodegradation.     

Poly(lactic acid)–thermoplastic starch–cotton composites: Starch-compatibilizing effects and composite biodegradability

Poly(lactic acid) (PLA) is a biodegradable, brittle, and high-cost polymer, which can be applied over structural components and green packaging. In this study, we reinforced PLA with natural cotton (10 wt %) and thermoplastic starch (TPS; 3 wt %) to obtain a biodegradable and lower cost composite. TPS was incorporated in three distinct ways: it was blended, coated, and blended and coated. In this study, we investigated the compatibilization of TPS in the improvement of matrix-reinforcement adhesion and increase in the tensile behavior without a compromise in biodegradation. The samples were investigated with thermal analysis, dynamic mechanical thermal analysis, tensile testing, scanning electron microscopy, confocal laser scanning microscopy, and hydrolytic degradation. The results show that the coupling effect was more pronounced in the PLA_TPS–cotton_TPS (hybrid system with PLA and cotton) hybrid system. This formulation presented a higher glass-transition temperature, thermal stability, storage modulus, wettability, and ductility. The TPS addition improved the adhesion between the matrix and starched cotton fiber and retarded abiotic biodegradation. These properties will allow for green applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47490.     

Morphology and properties tuning of PLA/cellulose nanocrystals bio-nanocomposites by means of reactive functionalization and blending with PVAc

A novel method for the preparation of PLA bio-nanocomposites containing cellulose nanocrystals (CNCs) is reported. In order to enhance interfacial adhesion and dispersion of nanocrystals into PLA matrix, functionalization of PLA and CNCs by radical grafting of glycidyl methacrylate (GMA) and pre-dispersion of CNCs in poly (vinyl acetate) (PVAc) emulsion were applied. Morphologies, thermal and mechanical properties of nanocomposites for CNCs content of 1–6 wt.% were examined. Addition of functionalized components (PLA-GMA, CNC-GMA) and/or PVAc dispersed CNCs both improved the phase distribution of nanofiller and tensile properties, compared to the binary PLA/CNC nanocomposites. Thermal analyses demonstrated that glass transition, melting temperature and crystallinity of PLA were affected by the PVAc amount. Nanocomposites with PVAc dispersed CNCs exhibited higher thermal resistance than other composites. The filler effectiveness (CFE) was evaluated for all samples on the basis of storage modulus values: CNC-GMA and PVAc dispersed CNCs (3 wt. %) resulted the most effective fillers.     

Influence of montmorillonite layered silicate on plasticized poly(l-lactide) blown films

Plasticized poly(l-lactide) (PLA) montmorillonite layered silicate (MLS) nanocomposites were compounded and blown-film processed using a co-rotating twin screw extruder. PLA was mixed with 10 wt% acetyltriethyl citrate ester plasticizer and 5 wt% of an organically modified montmorillonite at various screw speeds. Wide-angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM) determined that the compounded pellets and the blown film PLA/MLS nanocomposites were intercalated. The effect of processing screw speeds on the barrier, thermal, mechanical, and biodegradation properties of the nanocomposites were analyzed and compared to the neat polymer. Nanocomposite films show a 48% improvement in oxygen barrier and a 50% improvement in water vapor barrier in comparison to the neat PLA. The thermogravimetric analysis (TGA) showed an overall 9 °C increase in the decomposition temperature for all of the nanocomposites. Differential scanning calorimetry (DSC) has determined that the glass transition, cold crystallization and melting point temperatures were not significantly influenced by the presence of MLS. Mechanical properties of the nanocomposites showed that the Young's modulus increased by 20% and the ultimate elongation of the nanocomposites were not sacrificed in comparison to the neat samples. Biodegradation rates in soil were slightly greater for the PLA/MLS nanocomposite than the pure PLA. However, none of the PLA pure and nanocomposites achieved significant biodegradation levels after 180 days.     

Quaternary ammonium‐functionalized polymers in biodegradable matrices: Physicochemical properties,morphology, and biodegradability

Quaternary ammonium‐functionalized polymers (QAFPs) based on branched structures of poly(lactic acid) (PLA) and polycaprolactone (PCL) were blended with neat matrices of PLA and PCL to improve their processability in the melt phase at 160 °C. Different formulations were prepared by varying the proportions of the components of the blends (0, 10, 20, 50, and 60 wt % of QAFP). The rheological behavior of each component and their blends was studied at 160 °C and dynamic mechanical analyses were carried out. The thermal properties of the matrices were also investigated by thermogravimetric analyses and differential scanning calorimetry; they were found to be affected by the presence of QAFPs within them. All the studied blends had a dispersed morphology, highlighted by scanning electron microscopy. The water contact angle of the blends was studied and showed that the hydrophilicity of the surfaces of the blends increased by increasing their QAFP content. The biodegradability of both the components and the blends was investigated: a decrease of the biodegradation kinetics was observed due to the presence of the quaternary ammonium groups, but the materials remain biodegradable. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45261.     

Viscoelastic,thermo-mechanical and environmental properties of composites based on polypropylene/poly(lactic acid) blend and copper modified nanoclay

Poly(lactic acid) (PLA)/polypropylene (PP) blends composites were prepared by incorporating 3 wt.% of copper modified montmorillonite (MMT-Cu²⁺), obtained using cation exchange in a CuSO₄ solution, and 10 wt.% of polypropylene-graft-maleic anhydride (PP-g-MA) as a compatibilizer then varying the PLA content until 50 wt.%. These materials were subjected to several investigations such as X-rays diffraction, dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and tensile and environmental tests. The DMTA analysis showed that the glassy PLA high stiffness and the PP crystalline phase compensate the decrease in the storage modulus occurring during the PP and PLA glass transitions, respectively. The variations of tan δ revealed no changes on the PP and PLA phases glass transitions temperatures which indicate the immiscibility of the two polymers, as supported by DSC analysis. Blends composites SEM micrographs stated the immiscibility of the system resulting in the poor adhesion of the PLA droplets to the PP matrix. Also, the blends composites exhibited intermediate tensile properties between those of PP and PLA. The incorporation of MMT-Cu²⁺ to the (50/50) PP/PLA blend accentuated its aptitude to water absorption and ensured an efficient antimicrobial activity over a satisfactorily long period of around six months.     

PLA/PPC/OMMT纳米复合材料的结构与性能研究

采用双螺杆挤出机制备了聚乳酸（PLA）/聚碳酸亚丙酯（PPC）共混物和PLA/PPC/有机改性蒙脱土（OMMT）纳米复合材料,采用偏光显微镜、差示扫描量热仪和力学性能试验机等对共混物和纳米复合材料的相态结构、熔融与结晶行为和力学性能等进行了研究。结果表明,在PPC含量低于30 %时,随着PPC含量的增加,PLA/PPC和PLA/PPC/OMMT体系中PLA的玻璃化转变温度（Tg）均降低,在PPC含量为50 %时出现了明显的相分离;随着PPC含量的增加,PLA/PPC的冲击强度增大;OMMT的含量小于1.5 %时,PLA/PPC/OMMT体系的结晶度、拉伸强度、断裂伸长率和冲击强度均随OMMT含量的增加而增大。     

Great enhancement of mechanical features in PLA based composites containing aligned few layer graphene (FLG), the effect of FLG loading,size, and dispersion on mechanical and thermal properties

Four series of polylactide (PLA) based composite films containing horizontally aligned few layer graphene (FLG) flakes of high aspect ratio and adsorbed albumin are prepared. The mechanical and thermal properties varies with percentage, dispersion degree and size of FLG flakes. Great improvement up to 290% and 360% of tensile modulus and strength respectively were obtained for the composite containing high lateral size of FLG at 0.17% wt, and up to 60% and 80% for the composite with very well dispersed 0.02% wt FLG. The composites of PLA and PEG-PLLA containing very well dispersed FLG flakes at 0.07% wt are ductile showing enhancement of elongation at break up to respectively 80% and 88%. Relatively high electrical conductivity, 5 × 10⁻³ S/cm, is measured for PLA film charged with 3% of FLG.     

Effect of organically modified montmorillonite (OMMT) on biodegradation of PS:PLA and PS:PLA:OMMT using Phanerochaete chrysosporium

The environmental issues of synthetic polymers have been resolved using biodegradation under controlled conditions. The degradation study of polymeric composites of (a) polystyrene (PS) and poly(lactic acid) (PLA) (PS:PLA), and (b) PS:PLA filled with organically modified montmorillonite (OMMT) (PS:PLA:OMMT) was carried out using Phanerochaete chrysosporium . PLA was synthesized using l ‐lactic acid under controlled ultrasound cavitation technique, dried and added to a solution of PS. Surface of montmorillonite (MMT) was modified using column chromatographic technique to improve d‐spacing up to 31.5 Å. The sheets of PS:PLA and PS:PLA:OMMT were subjected to degradation study in minimal medium using P. chrysosporium micro‐organism under controlled conditions up to 28 days. The growth of micro‐organism and fractures inside the polymer matrix before and after degradation was observed using scanning electron microscope. Change in extracellular protein content, biomass production, and % degradation with respect to time of incubated samples have been also studied. It was found that the PS:PLA:OMMT (at 5 phr OMMT content) and PS:PLA (at 30% PLA) composites show an increment in degradation. The presence of OMMT leads to faster degradation of PS:PLA:OMMT nanocomposites, which decreases in mechanical property by 30% of PLA and 5 wt% of OMMT content. POLYM. COMPOS., 38:1292–1301, 2017. © 2015 Society of Plastics Engineers     

3D printed polylactide-based zirconia-toughened alumina composites: fabrication,mechanical, and in vitro evaluation

Fused deposition modeling (FDM) has been a commonly used technique in the fabrication of geometrically complex biodegradable scaffolds for bone tissue engineering. Generally, either individual polylactide (PLA) or its combination with calcium phosphates or bioglass has been employed to design scaffolds through the principles of FDM. In this study, FDM protocol has been employed to design 3D printed PLA/zirconia-toughened alumina (ZTA). A series of PLA/ZTA combinations have been attempted to determine the feasibility of the resultant in filament extrusion and their subsequent capacity to obtain a stable 3D printed component. A maximum of 80 wt.% PLA and 20 wt.% ZTA has been determined as an optimum combination to yield a stable 3D structure beyond which an enhanced ZTA content in the PLA matrix yielded a fragile filament that lacked effectiveness in 3D printing. 5 and 10 wt.% of ZTA addition in the PLA matrix produced a better 3D design that reasonably displayed good mechanical properties. Depending on the ceramic content, a homogeneous dispersion of the constituent elements representative of ZTA has been determined throughout the PLA matrix. Simulation studies through finite element analysis (FEA) exhibited good corroboration with the test results obtained from the mechanical studies.     

Semi-interpenetrating polymer networks composed of poly(l-lactide) and diisocyanate-bridged 4-arm star-shaped ɛ-caprolactone oligomers

Semi-interpenetrating polymer networks (semi-IPNs) were prepared by reactions of methylenediphenyl 4,4’-diisocyanate (MDI) and hydroxy-terminated 4-arm star-shaped ε-caprolactone oligomers (H4CLO_n's) with the degrees of polymerization per one arm, n = 3, 5 and 10 in the presence of poly(l-lactide) (PLA). Morphologies, thermal and mechanical properties of the MDI-bridged H4CLO_n (MH4CLO_n)/PLA semi-IPNs were evaluated by comparing with those of poly(?-caprolactone) (PCL)/PLA blends. Two tan δ peaks related to MH4CLO_n and PLA were observed in a dynamic mechanical curve of the semi-IPN. Although all the semi-IPNs and blends had micro-phase separated morphologies, the phase-separated droplets of MH4CLO₅/PLA 50/50 were much finer than those of PCL/PLA 50/50. Differential scanning calorimetry (DSC) analyses revealed that MH4CLO₃ and MH4CLO₅ are substantially amorphous, while MH4CLO₁₀ is semi-crystalline, and that cold crystallization of the PLA component of MH4CLO_n/PLA is more strongly disturbed for the semi-IPN with a smaller n value and more MH4CLO_n content. Tensile modulus, toughness and elongation at break of MH4CLO₅/PLA 50/50 semi-IPN were much higher than those of PCL/PLA 50/50 blend.     

Degradability Enhancement of Poly(Lactic Acid) by Stearate-Zn(3)Al LDH Nanolayers

Recent environmental problems and societal concerns associated with the disposal of petroleum based plastics throughout the world have triggered renewed efforts to develop new biodegradable products compatible with our environment. This article describes the preparation, characterization and biodegradation study of poly(lactic acid)/layered double hydroxide (PLA/LDH) nanocomposites from PLA and stearate-Zn₃Al LDH. A solution casting method was used to prepare PLA/stearate-Zn₃Al LDH nanocomposites. The anionic clay Zn₃Al LDH was firstly prepared by co-precipitation method from a nitrate salt solution at pH 7.0 and then modified by stearate anions through an ion exchange reaction. This modification increased the basal spacing of the synthetic clay from 8.83 Å to 40.10 Å. The morphology and properties of the prepared PLA/stearate-Zn₃Al LDH nanocomposites were studied by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), thermogravimetric analysis (TGA), tensile tests as well as biodegradation studies. From the XRD analysis and TEM observation, the stearate-Zn₃Al LDH lost its ordered stacking-structure and was greatly exfoliated in the PLA matrix. Tensile test results of PLA/stearate-Zn₃Al LDH nanocomposites showed that the presence of around 1.0–3.0 wt % of the stearate-Zn₃Al LDH in the PLA drastically improved its elongation at break. The biodegradation studies demonstrated a significant biodegradation rate improvement of PLA in the presence of stearate-Zn₃Al LDH nanolayers. This effect can be caused by the catalytic role of the stearate groups in the biodegradation mechanism leading to much faster disintegration of nanocomposites than pure PLA.     

Enhancing the PLA Crystallization Rate and Mechanical Properties by Melt Blending with Poly(styrene-butadiene-styrene) Copolymer

Poly(styrene-butadiene-styrene) (SBS) copolymer was used to enhance the crystallization ability and mechanical properties of poly(L-lactic acid) (PLA) through melt mixing. The thermogravimetric analysis and Fourier transform infrared results revealed the n–π interaction between PLA and SBS. Differential scanning calorimetry and X-ray diffraction analysis indicated that the crystallization ability of the PLA improved substantially. The PLA crystallized completely during the cooling process when the SBS content in the blend was above 20 wt.%. The elongation at break and the impact resistance were significantly improved compared with that of neat PLA when the SBS content was above 50 wt.%.     

Effects of hetero-armed star-shaped PCL-PLA polymers with POSS core on thermal,mechanical, and morphological properties of PLA

In this study, AB type-heteroarm star-shaped poly(ε-caprolactone)-poly(lactic acid) (PCL-PLA) polymers with polyhedral oligomeric silsesquioxane (POSS) core ((PCL)₄-POSS-(PLA)₄, coded as SPLA) were synthesized successfully by using ring opening polymerization and click chemistry techniques together. The synthesized polymers were compounded with commercial PLA at different blending ratios (PLA/SPLA = 100/0, 95/5, 90/10, and 80/20% wt). The effects of heteroarm SPLA polymers having different arm lengths (n = 10, 20, 30, and 50) on morphological, mechanical, and thermal behaviors of PLA were investigated. It is determined that SPLA polymers with four PLA and four PCL arms on its structure enhanced mechanical properties of PLA. The tensile modulus decreased, and lowest modulus values were observed with blends prepared at 80/20 ratio. Elongation at break values increased in all blends, maximum increment was observed with 1,4-phenylene diisocyanate (PDI) containing SPLA20 blends prepared at 90/10 ratio. This result showed that SPLA20 had optimum chain length for chain extension reactions of between PLA chains. Besides, a trade compatibilizer PDI was utilized to enhance the intercompatibility of binary polymer blends.     

Oxidized multiwalled carbon nanotubes as effective reinforcement and thermal stability agents of poly(lactic acid) ligaments

In this study, nanocomposites of poly(lactic acid) (PLA) containing 0.5, 1, and 2.5 wt % oxidized multiwalled carbon nanotubes (MWCNT–COOHs) were prepared by the solved evaporation method. From transmission electron microscopy and scanning electron microscopy micrographs, we observed that the MWCNT–COOHs were well dispersed in the PLA matrix and, additionally, there was increased adhesion between PLA and the nanotubes. As a result, all of the studied nanocomposites exhibited higher mechanical properties than neat PLA; this indicated that the MWCNT–COOHs acted as efficient reinforcing agents, whereas in the nonoxidized multiwalled carbon nanotubes, the mechanical properties were reduced. Nanotubes can act as nucleating agents and, thereby, affect the thermal properties of PLA and, especially, the crystallization rate, which is faster than that of neat PLA. From the thermogravimetric data, we observed that the PLA/MWCNT–COOH nanocomposites presented relatively better thermostability than PLA; this was also verified from the calculation of activation energy. On the contrary, the addition of MWCNT–COOH had a negative effect on the enzymatic hydrolysis rate of PLA. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Study of silane treatment on poly‐lactic acid(PLA)/sepiolite nanocomposite thin films

Poly‐lactic acid (PLA) nanocomposite film was prepared with untreated and silane treated sepiolite through solution casting method. Sepiolite is found to be promising nano inorganic filler used to prepare biodegradable PLA nanocomposite films. The effect of sepiolite loading on the thermal, mechanical, gas permeability, and water vapor permeability (WVP) properties of the films was investigated. X‐ray diffraction analysis revealed the crystallinity index and well dispersed sepiolite in PLA/sepiolite thin films. By modifying sepiolite, depending on the nanoclay content, the mechanical properties of films were enhanced. PLA/sepiolite films exhibited improved gas barrier and WVP properties compared to neat PLA. The scanning electron microscope results demonstrated that there is a good interface interaction between sepiolite and PLA. The surface treatment of sepiolite increased the adhesion of the PLA matrix to the sepiolite nanoclay which yielded better mechanical properties of the films as compared to pure PLA. It was observed after 1.5% wt sepiolite, nano‐filler tended to agglomerate, therefore mechanical and barrier properties of films decreased. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41428.     

Effects of molten poly(3-hydroxybutyrate) on crystalline morphology in stereocomplex of poly(L-lactic acid) with poly(D-lactic acid)

Effects of poly(3-hydroxybutyrate) (PHB) on crystalline morphology of stereocomplexing capacity of poly(L- and D-lactic acid) (PLLA and PDLA) were studied by differential scanning calorimetry (DSC), polarizing-light optical microscopy (POM), atomic-force microscopy (AFM) and wide-angle X-ray diffraction (WAXD). When crystallized at high T_c (130 °C or above), morphology transition of stereocomplexed PLA (sc-PLA) occurs from original well-rounded Maltese-cross spherulites to dendritic form in blends of high PHB contents (50 wt.% or higher), where PHB acts as an amorphous species. Microscopy characterizations show that morphology of sc-PLA in PHB/sc-PLA blends crystallized at T_c = 170 °C no longer retain original complexed Maltese-cross well-rounded spherulites; instead, the spherulites are disintegrated and restructured into two types of dendrites: (1) edge-on feather-like dendrites (early growth) and (2) flat-on wedge-like crystal plates (later growth) by growing along different directions and exhibiting different optical brightness. The concentration and/or distribution of amorphous PHB at the crystal growth front, corresponding to variation of the slopes of spherulitic growth rates, is a factor resulting in alteration and restructuring of the sc-PLA spherulites in the blends. Despite of spherulite disintegration, WAXD result shows that these two PHB-induced dendrites still retain the original unit cells of complexes, and thus these two new dendrites are sc-PLA.     

Wood flour/polylactide biocomposites toughened with polyhydroxyalkanoates

Polylactide (PLA)‐based wood–plastic composites (WPCs) were successfully manufactured by extrusion blending followed by injection molding. The effects of polyhydroxyanoates (PHAs) on the mechanical and thermal properties and the morphologies of the PLA‐based WPCs were investigated with mechanical testing, thermal analysis, and scanning electronic microscopy (SEM). The inclusion of PHAs in the PLA‐based WPCs produced an increase in the impact resistance and a decrease in the tensile strength. The brittle–ductile transition of the impact strength for the PLA‐based WPCs toughened with PHAs was confirmed when the wood flour content was between 15 and 35 wt %. SEM images showed that the fracture surfaces of the PLA‐based WPCs toughened with PHAs were rougher than that of their nontoughened counterparts. The ternary PLA‐based WPCs exhibited ductile fracture during mechanical testing. Differential scanning calorimetry (DSC) showed that addition of PHAs into the composites caused deviations of the cold crystallization temperature and melting temperature of PLA. Thermogravimetric analysis indicated that the PHAs reduced the thermal stability of the PLA‐based WPCs. PHAs can be a green toughening agent for PLA‐based WPCs. The specific properties evidenced by the biocomposites may hint at their potential application, for example, in the automotive industry and civil engineering. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

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

Acetyl tri‐n‐butyl citrate (ATBC) and poly(ethyleneglycol)s (PEGs) with different molecular weights (from 400 to 10000) were used in this study to plasticize poly(L‐lactic acid) (PLA). The thermal and mechanical properties of the plasticized polymer are reported. Both ATBC and PEG are effective in lowering the glass transition (T_g) of PLA up to a given concentration, where the plasticizer reaches its solubility limit in the polymer (50 wt % in the case of ATBC; 15–30 wt %, depending on molecular weight, in the case of PEG). The range of applicability of PEGs as PLA plasticizers is given in terms of PEG molecular weight and concentration. The mechanical properties of plasticized PLA change with increasing plasticizer concentration. In all PLA/plasticizer systems investigated, when the blend T_g approaches room temperature, a stepwise change in the mechanical properties of the system is observed. The elongation at break drastically increases, whereas tensile strength and modulus decrease. This behavior occurs at a plasticizer concentration that depends on the T_g‐depressing efficiency of the plasticizer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1731–1738, 2003     

Production and investigation of structure and properties of polyethylene–polylactide composites

Under conditions of shear deformations, low-density polyethylene (LDPE) and polylactide (PLA) composites are obtained in rotor disperser. The production of these composites allows one to use polymers derived from natural raw and to reduce the cost of the materials on their base. The addition of rigid PLA leads to increase in elastic modulus from 200 for LDPE to 1190 for LDPE–PLA (50:50 wt %) composites and in tensile strength from 13.3 for LDPE to 17.8 for LDPE–PLA. By differential scanning calorimetry method, it is shown that LDPE and PLA are incompatible. Using X-ray diffraction analysis, it is found that degree of crystallinity of composites decreases from 46.1 at 50:50 wt % to 36.9 at 80:20 wt % component ratios with the rise in LDPE content. Tests on fungus resistance show that the composites containing 50 wt % PLA are more resistant than the composites containing 30 wt % PLA. First by gel-permeation chromatography method, it is shown that composite degradation after exposure in soil is accompanied by the PLA chain scission and depolymerization with formation of monomers and dimers (M _w of PLA decreases from 118,860 to 80,100). The obtained composites can be applied as packaging materials. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47598.