Investigation of structure and mechanical properties of toughened poly(l‐lactide)/thermoplastic poly(ester urethane) blends

In this study, poly(l ‐lactide) (PLA) is melt‐blended with thermoplastic polyurethane (TPU) to modify the brittleness of PLA. An aliphatic ester‐based TPU was selected in order to have an ester sensitivity for degradation and an inherent biocompatibility. Using this compatible TPU, there was no need to apply problematic compatibilizers, so the main positive properties of PLA such as biocompatibility and degradability were not challenged. The detected microstructure of PLA/TPU blends showed that when the TPU content was lower than 25 wt %, the structure appeared as sea‐islands, but when the TPU content was increased, the morphology was converted to a cocontinuous microstructure. A higher interfacial surface area in the blend with 25 wt % TPU (PLA25) resulted in a higher toughness and abrasion resistance. The various analyses confirmed interactions and successful coupling of two phases and confirmed that melt‐blending of PLA with the aliphatic ester‐based TPU is a convenient, cost‐effective, and efficient method to conquer the brittleness of PLA. The prepared blends are general‐purpose plastics, but PLA25 showed an optimum mechanical strength, toughness, and biocompatibility suitable for a wide range of applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43104.     

Structure and properties of PP/POE/HDPE blends

This work was aimed to counteract the effect of ethylene‐α‐olefin copolymers (POE) by reinforcing the polypropylene (PP)/POE blends with high density polyethylene (HDPE) particles and, thus, achieved a balance between toughness and strength for the PP/POE/HDPE blends. The results showed that addition of HDPE resulted in an increasing wide stress plateau and more ductile fracture behavior. With the increase of HDPE content, the elongation at break of the blends increased rapidly without obvious decrease of yield strength and Young's modulus, and the notched izod impact strength of the blends can reach as high as 63 kJ/m² at 20 wt % HDPE loading. The storage modulus of PP blends increased and the glass transition temperature of each component of the blends shifted close to each other when HDPE was added. The crystallization of HDPE phase led to an increase of the total crystallinity of the blend. With increasing HDPE content, the dispersed POE particle size was obviously decreased, and the interparticle distance was effectively reduced and the blend rearranged into much more and obvious core‐shell structure. The fracture surface also changed from irregular striation to the regularly distant striations, displaying much obvious character of tough fracture. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Improvement in toughness and crystallization of poly(L‐lactic acid) by melt blending with poly(epichlorohydrin‐co‐ethylene oxide)

Melt blending of poly(lactic acid) (PLA) and poly(epichlorohydrin‐co‐ethylene oxide) copolymers (ECO) was performed to improve the toughness and crystallization of PLA. Thermal and scanning electron microscopy analysis indicated that PLA and ECO were not thermodynamically miscible but compatible to some extent. The addition of a small amount of ECO accelerated the crystallization rate and increased the final crystallinity of PLA in the blends. Significant enhancement in toughness and flexibility of PLA were achieved by the incorporation of the ECO elastomer. When 20 wt% ECO added, the impact strength increased from 5 kJ/m² of neat PLA to 63.9 kJ/m², and the elongation at break increased from 5% to above 160%. The failure mode changed from brittle fracture of neat PLA to ductile fracture of the blend. Rheological measurement showed that the melt elasticity and viscosity of the blend increased with the concentration of ECO. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers.     

Morphology and properties of the biosourced poly(lactic acid)/poly(ethylene oxide‐b‐amide‐12) blends

Biosourced poly(lactic acid) (PLA) blends with different content of poly(ethylene oxide‐b‐amide‐12) (PEBA) were prepared by melt compounding. The miscibility, phase structure, crystallization behavior, mechanical properties, and toughening mechanism were investigated. The blend was an immiscible system with the PEBA domains evenly dispersed in the PLA matrix. The PEBA component suppressed the nonisothermal melt crystallization of PLA. With the addition of PEBA, marked improvement in toughness of PLA was achieved. The maximum for elongation at break and impact strength of the blend reached the level of 346% and 60.5 kJ/m², respectively. The phase morphology evolution in the PLA/PEBA blends after tensile and impact tests was investigated, and the corresponding toughening mechanism was discussed. It was found that the PLA matrix demonstrates obvious shear yielding in the blend during the tensile and impact tests, which induced energy dissipation and therefore lead to improvement in toughness of the PLA/PEBA blends. POLYM. COMPOS., 2013. © 2012 Society of Plastics Engineers     

Blends of polylactic acid with thermoplastic copolyester elastomer: Effect of functionalized terpolymer type on reactive toughening

This study is an attempt to explore the effectiveness of thermoplastic copolyester elastomer (TPCE) as a toughening agent for improving the impact strength of PLA. Biobased Hytrel^® thermoplastic copolyester of polyether glycol and polybutylene terephthalate was selected as the TPCE of choice for this study. Blends of PLA/Hytrel at varying weight ratios were prepared using extrusion followed by injection molding technique. Optimal synergies of two polymers were found in the PLA/Hytrel (70/30) blend, showing impact strength of 234 J/m, a sixfold increase compared to neat PLA. In order to obtain further enhancement in toughness, different functionalized terpolymers were added to accomplish reactive compatibilization. A series of functionalized terpolymers, ethylene methyle acrylate‐glycidyl methacrylate (EMA‐GMA), ethylene butyl acrylate‐glycidyl methacrylate (EBA‐GMA), ethylene methyl acrylate‐maleic anhydride (EMA‐MaH), and ethylene butyl acrylate‐maleic anhydride (EBA‐MaH) were selected. Comparing PLA ternary blends with different terpolymers, GMA containing terpolymers showed better impact toughness compared to MaH terpolymer blends. Unique fracture surface morphology showing debonding cavitation and massive shear yielding in the ternary blends containing EMA‐GMA resulted in super toughened blends. Highest zero shear viscosity and storage modulus was also observed for ternary blends with EMA‐GMA. Under the processing conditions and blend ratio investigated, EMA‐GMA showed better efficiency in improving the toughness of the PLA blends. POLYM. ENG. SCI., 58:280–290, 2018. © 2017 Society of Plastics Engineers     

Super‐Tough and Highly‐Ductile Poly(l‐lactic acid)/Thermoplastic Polyurethane/Epoxide‐Containing Ethylene Copolymer Blends Prepared by Reactive Blending

Ethylene‐methyl acrylate‐glycidyl methacrylate copolymer (E‐MA‐GMA) is employed to improve the impact toughness of poly(l ‐lactic acid) (PLLA)/thermoplastic polyurethane (TPU) blends by reactive melt‐blending. The reaction and miscibility between the components are confirmed by Fourier transform infrared spectroscopy, dynamic mechanical analysis, and differential scanning calorimetry. A super‐tough PLLA/TPU/E‐MA‐GMA multiphase blend (75/10/15) exhibits a significantly improved impact strength of 77.77 kJ m^?2, which is more than 17 times higher than that of PLLA/TPU (90/10) blend. A co‐continuous‐like TPU phase structure involving E‐MA‐GMA phase at the etched cryo‐fractured surface and the high‐orientated matrix deformation at the impact‐fractured surface are observed by scanning electron microscopy. The high‐orientated matrix deformation induced by the co‐continuous TPU phase structure is responsible for the super toughness of PLLA/TPU/E‐MA‐GMA blends.     

Influence of the morphology and viscoelasticity on the thermomechanical properties of poly(lactic acid)/thermoplastic polyurethane blends compatibilized with ethylene-ester copolymer

Viscoelastic, interfacial properties, and morphological data were employed to predict the thermal and mechanical properties of compatibilized poly(lactic acid) (PLA)/thermoplastic polyurethane (TPU) blends. The combination of interfacial thickness measured by contact angle and entanglement density determined by dynamical mechanical analysis analyze data was employed to evaluate the mechanical behavior of PLA/TPU blends with and without ethylene-butyl acrylate-glycidyl methacrylate (EBG) compatibilization agent. The PLA/TPU blend (70/30 wt %) was prepared in a Haake internal mixer at 190 °C and compatibilized with different contents of EBG. The evaluation of the interfacial properties revealed an increase in the interfacial layer thickness of the PLA/TPU blend with EBG. The scanning electronic microscopy images showed a drastic reduction in the size of the dispersed phase by increasing the compatibilizer agent EBG content in the blend. The compatibilization of the PLA/TPU blends improved both the Izod impact strength and yield stress by 38 and 33%, respectively, in comparison with neat PLA/TPU blend. The addition of EBG into PLA/TPU blends significantly increased the entanglement density and the PLA toughening but resulted in a decrease of PLA deformation at break. The PLA and TPU glass transitions were affected by the EBG, suggesting that the PLA and TPU domains were partially miscible. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48926.     

TPU/PLA nanocomposites with improved mechanical and shape memory properties fabricated via phase morphology control and incorporation of multi-walled carbon nanotubes nanofillers

Shape memory polymer nanocomposites based on thermoplastic polyurethane (TPU)/polylactic acid (PLA) blends filled with pristine multi-walled carbon nanotubes (MWCNTs) and modified MWCNTs─COOH were fabricated by direct melt blending technique and investigated for its morphology, mechanical, thermal, electrical, and shape memory properties. Morphological characterizations by using transmission electron microscope (TEM) and field emission scanning electron microscope (FESEM) revealed better dispersion of MWCNTs─COOH in the polymer blend, which is attributed to the improved interfacial interactions between the polymer blends and MWCNTs-COOH. Loading of the MWCNTs-COOH in the TPU/PLA blends resulted in the significant improvements in the mechanical properties such as tensile strength and elastic modulus and these effects are more pronounced on increasing the MWCNTs─COOH loading amount, when compared to the pristine MWCNTs filled system. Thermal analysis showed that the glass transition temperature of the blends increases slightly with increasing loading of both pristine and modified MWCNTs in the system. The resistance of nanocomposites decreased from 2 × 10¹² Ω to 3.2 × 10¹⁰ Ω after adding 3% MWCNTs─COOH. The shape memory performance tests showed that the enhancement of shape recovery by 252% could be achieved at 3% MWCNTs loading, when compared to that of TPU/PLA blends.     

High performance polylactic acid/thermoplastic polyurethane blends with in-situ fibrillated morphology

As an environment-friendly polyester, polylactic acid (PLA) shows great potential market value. While it still faces some obstacles in large-scale practical application due to its brittleness. In this work, a novel strategy to improve the toughness of polylactic acid is developed. By adjusting processing temperature during the melt-blending process, thermoplastic polyurethane/poly (D-lactic) acid/poly (L-lactic) acid (TPU/PDLA/PLLA) ternary blends with different morphology are obtained. The experimental results show that the TPU in ternary blends formed a fibrillated micro-morphology, and the interfacial compatibility between the components is improved when the processing temperature is adjusted to 200°C. Under the synergistic action of in-situ fibrillated TPU and stereocomplex (SC) crystals, the toughness of the ternary blends is improved significantly without sacrificing its own tensile strength. The maximum value of tensile strength, elongation at break, and fracture work of ternary blends are 61.9 MPa, 23.5%, and 1038.9 kJ/m³, respectively. In addition, the melt strength of ternary blends was significantly improved, which is a benefit to their processing application.     

Poly(lactic acid)–thermoplastic poly(ether)urethane composites synergistically reinforced and toughened with short carbon fibers for three‐dimensional printing

In this study, we prepared short‐carbon‐fiber (CF)‐reinforced poly(lactic acid) (PLA)–thermoplastic polyurethane (TPU) blends by melt blending. The effects of the initial fiber length and content on the morphologies and thermal, rheological, and mechanical properties of the composites were systematically investigated. We found that the mechanical properties of the composites were almost unaffected by the fiber initial length. However, with increasing fiber content, the stiffness and toughness values of the blends were both enhanced because of the formation of a TPU‐mediated CF network. With the incorporation of 20 wt % CFs into the PLA–TPU blends, the tensile strength was increased by 70.7%, the flexural modulus was increased by 184%, and the impact strength was increased by 50.4%. Compared with that of the neat PLA, the impact strength of the CF‐reinforced composites increased up to 1.92 times. For the performance in three‐dimensional printing, excellent mechanical properties and a good‐quality appearance were simultaneously obtained when we printed the composites with a thin layer thickness. Our results provide insight into the relationship among the CFs, phase structure, and performance, as we achieved a good stiffness–toughness balance in the PLA–TPU–CF ternary composites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46483.     

Morphology,mechanical, and rheological properties of poly(lactic acid)/ethylene acrylic acid copolymer blends processing via vane extruder

This work aimed to study, for the first time, the melt blending of poly(lactic acid) (PLA) and ethylene acrylic acid (EAA) copolymer by a novel vane extruder to toughen PLA. The phase morphologies, mechanical, and rheological properties of the PLA/EAA blends of three weight ratios (90/10, 80/20, and 70/30) were investigated. The results showed that the addition of EAA improves the toughness of PLA at the expense of the tensile strength to a certain degree and leads the transition from brittle fracture of PLA into ductile fracture. The 80/20 (w/w) PLA/EAA blend presents the maximum elongation at break (13.93%) and impact strength (3.18 kJ/m²), which is 2.2 and 1.2 times as large as those of PLA, respectively. The 90/10 and 80/20 PLA/EAA blends exhibit droplet‐matrix morphologies with number average radii of 0.30–0.73 μm, whereas the 70/30 PLA/EAA blend presents an elongated co‐continuous structure with large radius (2.61 μm) of EAA phase and there exists PLA droplets in EAA phase. These three blends with different phase morphologies display different characteristic linear viscoelastic properties in the low frequency region, which were investigated in terms of their complex viscosity, storage modulus, loss tangent, and Cole‐Cole plots. Specially, the 80/20 PLA/EAA blend presents two circular arcs on its Cole‐Cole plot. So, the longest relaxation time of the 80/20 blend was obtained from its complex viscosity imaginary part plot, and the interfacial tension between PLA and EAA, which is 4.4 mN/m, was calculated using the Palierne model. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40146.     

Scrutinizing the influence of peroxide crosslinking of dynamically vulcanized EVA/TPU blends with special reference to cable sheathing applications

A novel thermoplastic vulcanizate (TPV) based on the blends of ethylene vinyl acetate/thermoplastic polyurethane (EVA/TPU) at various blend ratios has been developed via dynamic vulcanization at 180 °C using di‐(2‐tert‐butyl peroxy isopropyl) benzene (DTBPIB) peroxide as the cross‐linking agent. Modification of the EVA/TPU blends via dynamic crosslinking significantly improves the tensile strength and modulus of the system and the improvement is more significant for EVA/TPU 50/50 and 60/40 blends. AFM study shows that crosslinked EVA particles are dispersed in the continuous TPU matrix and the dispersed EVA domain sizes are relatively smaller in EVA/TPU 50/50 and 60/40 blends leading to good mechanical properties. FTIR spectroscopy has been used to characterize the specific chemical changes occurring due to dynamic vulcanization. This TPV has excellent retention of physico‐mechanical properties even after reprocessing twice and the blends also have very good thermal resistance as indicated by aging study. The samples were found to exhibit remarkable improvement in oil resistance property as compared to their uncrosslinked counterpart. The creep behavior of the blends significantly improves after dynamic crosslinking and blends with higher TPU content show better creep resistance. Volume resistivity of all the peroxide vulcanized blends is in the range of 10¹³ ohm cm, which is suitable for cable sheathing application. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43706.     

Improvement in toughness and crystallization of poly(L‐lactic acid) by melt blending with ethylene/methyl acrylate/glycidyl methacrylate terpolymer

Melt blending of poly(lactic acid) (PLA) and ethylene/methyl acrylate/glycidyl methacrylate terpolymer (EGA) containing relatively high‐concentration epoxide groups (8 wt%) was performed to improve the toughness and crystallization of PLA. The results of nonisothermal and isothermal crystallization investigation showed that the addition of EGA accelerated the crystallization rate and increased the final crystallinity of PLA in the blends. Significant enhancement in toughness and flexibility of PLA were achieved by the incorporation of the EGA elastomer. When 20 wt% EGA added, the impact strength increased from 3.0 kJ m^?2 of neat PLA to 59.8 kJ m^?2 and the elongation at break increased from 4.9 to 232.0%. The failure mode changed from brittle fracture of neat PLA to ductile fracture of the blend. POLYM. ENG. SCI., 53:2498–2508, 2013. © 2013 Society of Plastics Engineers     

异氰酸酯对聚乳酸/热塑性聚氨酯共混物性能的影响

以4,4^′-二苯基甲烷二异氰酸酯（MDI）为反应增容剂，采用熔融共混法制备了不同MDI含量的聚乳酸/热塑性聚氨酯（PLA/TPU）共混物，采用傅里叶变换红外光谱仪（FTIR）、万能试验机、冲击试验机、扫描电子显微镜（SEM）、差示扫描量热仪（DSC）和旋转流变仪对共混物力学性能、微观形态、热性能和流变性能进行了研究。结果表明：MDI可以有效改善共混物的力学性能，当MDI质量分数为1%时，共混物力学性能最佳，缺口冲击强度为40.0kJ/m²，断裂伸长率为214.1%，与未加MDI的共混物相比，分别增加了4.3倍和5.8倍，拉伸强度稍有下降（47.6MPa）；SEM表明，MDI的加入提高了共混物的相容性，加入MDI后，共混物的断面由海-岛结构变为核-壳包覆结构，相界面作用力增强；DSC测试表明，共混物的玻璃化转变温度、冷结晶温度和熔融温度随着MDI含量的增加而升高；流变测试表明，MDI质量分数的增加，共混物呈现更显著的剪切变稀行为，推测共混反应机理为：MDI质量分数的增加，体系内依次发生PLA的扩链、支化和TPU的交联。     

环氧化杜仲胶增韧改性聚乳酸的性能

采用熔融共混法将环氧化杜仲胶(EEUG)用于聚乳酸(PLA)的增韧改性,制备了具有良好韧性的全生物基PLA/EEUG共混物,考察了EEUG用量对共混物的热性能、动态力学性能、力学性能及微观形貌等的影响.结果表明,PLA/EEUG共混物为典型的两相不相容体系.EEUG的加入限制了PLA分子链的运动,导致PLA的结晶度下降...     

Interfacial reaction and its influence on phase morphology and impact properties of modified‐polyacetal/thermoplastic polyurethane blends

The cationic polymerization of 1,3,5‐trioxane, 1,3‐dioxolane and a small amount of 2‐hydroxyacetic acid (HAA) was carried out, and the resulting modified‐polyacetal (POM) was blended with thermoplastic polyurethane (TPU) in melt. The results of ¹H NMR analysis indicated that HAA was almost incorporated in the modified‐POM, and that the resulting carboxyl end‐group and hydroxyl end‐group in the modified‐POM reacted with TPU during the melt blending. There were many boundary layers between the cavities and matrix in the modified‐POM/TPU (82/18 by weight) blend that was etched with tetrahydrofuran (THF), and the diameter of the cavities became ～0.3–1 μm long when the blending time reached 10 min. The results of scanning electron microscopic (SEM) observation and dynamic mechanical analysis (DMA) indicated that the modified‐POM/TPU blend had a good compatibility because of the interfacial reaction between the modified‐POM and TPU phase in the blend. The modified‐POM/TPU blend exhibited higher Charpy impact strength when compared with a normal‐POM/TPU blend; the toughness of the modified‐POM/TPU blend attributed to the good compatibility between the two phases. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4375–4382, 2006     

Biodegradable poly(lactic acid)/poly(butylene succinate)/wood flour composites: Physical and morphological properties

This work sought to improve the toughness and thermal stability of poly(lactic acid) (PLA) by incorporating poly(butylene succinate) (PBS) and wood flour (WF). The PLA/PBS blends showed a PBS‐dose‐dependent increase in the impact strength, elongation at break, degree of crystallinity, and thermal stability compared to the PLA, but the tensile strength, Young's modulus, and flexural strength were all decreased with increasing PBS content. Based on the optimum impact strength and elongation at break, the 70/30 (w/w) PLA/PBS blend was selected for preparing composites with five loadings of WF (5–30 phr). The impact strength, tensile strength, flexural strength, and thermal stability of the PLA/PBS/WF composites decreased with increasing WF content, and the degree of crystallinity was slightly increased compared to the 70/30 (w/w) PLA/PBS blend. Based on differential scanning calorimetry, the inclusion of PBS and WF into PLA did not significantly change the glass transition and melting temperatures of PLA in the PLA/PBS blends and PLA/PBS/WF composites. From the observed cold crystallization temperature of PLA in the samples, it was evident that the degree of crystallinity of PLA in all the blends and composites was higher than that of PLA. The PLA/PBS blend and PLA/PBS/WF composite degraded faster than PLA during three months in natural soil, which was due to the fast degradation rate of PBS. POLYM. COMPOS., 38:2841–2851, 2017. © 2016 Society of Plastics Engineers     

Toughening of recycled polystyrene used for TV backset

The recycled polystyrene (rPS) was toughened with ethylene‐octylene copolymer thermoplastic elastomer (POE) and high‐density polyethylene (HDPE) with various melt flow index (MFI), compatibilized by styrene‐butadiene‐styrene copolymer (SBS) to enhance the toughness of rPS for use as TV backset. The rPS/POE binary blends exhibited an increased impact strength with 5–10 wt % POE content followed by a decrease with the POE content up to 20 wt %, which could be due to poor compatibility between POE and rPS. For rPS/POE/SBS ternary blends with 20 wt % of POE content, the impact strength increased dramatically and a sharp brittle‐ductile transition was observed as the SBS content was around 3–5 wt %. Rheological study indicated a possible formation of network structure by adding of SBS, which could be a new mechanism for rPS toughening. In rPS/POE/HDPE/SBS (70/20/5/5) quaternary blends, a fibril‐like structure was observed as the molecular weight of HDPE was higher (with lower MFI). The presence of HDPE fibers in the blends could not enhance the network structure, but could stop the crack propagation during fracture process, resulting in a further increase of the toughness. The prepared quaternary blend showed an impact strength of 9.3 kJ/m² and a tensile strength of 25 MPa, which can be well used for TV backset to substitute HIPS because this system is economical and environmental friendly. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

A comparative study on different rubbery modifiers: Effect on morphologies,mechanical, and thermal properties of PLA blends

To improve the impact toughness of poly(lactic acid) (PLA), four kinds of rubbery modifiers, including ground tyre rubber (GTR), styrene‐butadiene‐styrene block copolymer (SBS), ethylene‐α‐octene copolymer (EOC) and glycidyl methacrylate grafted EOC (mEOC), were introduced for fabricating the PLA blends. The morphological structures, mechanical properties, thermal stability and thermal decomposition kinetics of pristine PLA and the blends were investigated. Results showed that representative droplet‐matrix structures were observed in the PLA blends, of which the PLA/SBS blend presented the smallest domains while PLA/EOC case had the largest elastomeric particle size. Accordingly, the highest impact toughness and elongation at break were achieved by PLA/SBS blend, whereas the tensile strength and elastic modulus for the blends were all lower than that of pristine PLA. Though the incorporation of rubbery modifiers barely altered the peak temperature of melting, the degrees of crystallinity for blends were declined sharply. The results of thermo gravimetric analysis indicated thermal degradation process of PLA phase was accelerated by rubbery modifiers and evidenced by the relative higher mass conversion at peak temperature. The reaction order of PLA phase for blends calculated by Carrasco method exhibited similar values when compared with control sample. However, the values of activation energy were rather lower than that of pure PLA. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43340.     

Mechanical,thermal, and biodegradability properties of PLA/modified starch blends

Three different kinds of modified starch (MS) were prepared as fillers to assess the compatibility between them and poly(lactic acid) (PLA) resin. The blends were prepared by incorporating 15 wt% of the MS into PLA using a twin‐screw extruder. Through morphology analysis, it can be seen that the dispersion state of MS granules was greatly different. Investigations of thermal behavior indicated that the addition of MS decreased thermal properties which found expression in the decrease of melting temperature and vicat softening temperature (VST). But thermal stability of PLA/maleic anhydride grafted starch (MA‐g‐ST) was slightly higher than those of other blends. PLA/MA‐g‐ST blend exhibited the highest notched impact strength, elongation at break, and tensile strength, which means MA‐g‐ST was suitable as a filler improving the toughness of PLA. It was also proved that biodegradability rate of blends increased dramatically and reached up to 1.80, 1.89, 1.44 g day⁻¹ after 60 days, respectively. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers