The Effects of Additives on the Biodegradation of Polycaprolactone Composites

Because environmental pollution caused by plastic waste is a major problem investigations concerning biodegradable packaging are important and required. In this study, the biodegradation of PCL composite films with organic (glycerol monooleate and oleic acid) and inorganic additives (organo nano clay) was investigated to understand which additive and the amount of additive was more effective for biodegradation. The relationship between the degree of crystallinity and the effect of additives on the biodegradability of polycaprolactone (PCL) was examined. PCL composite films were prepared using organo nano clay (0.1–0.4–1–3 wt%) and oleic acid (1–3–5 wt%) or GMO (1–3–5 wt%). The 35 films prepared with PCL (P), clay (C), oleic acid (O), or glycerol monooleate (G) are coded as P_C#wt%_O (or G)#wt%. The composite films, P_C0.4_O5 contains 0.4 wt% clay and 5 wt% oleic acid and the P_C3_G1 contains 3 wt% clay and 1 wt% glycerol monooleate. The biodegradation of PCL films in simulated soil was studied for 36 months. The films were periodically removed from the simulated soil and film thicknesses, weight losses, visual changes, crystal structures, and a functional group analyses were performed. PCL composite films are separated into three groups, depending on degradation time, (1) films that degraded before 8 months (fast degradation), (2) films that degraded around 24 months (similar to neat PCL), and (3) films that take longer to degrade (slow degradation). The films in the first group are PCL films with 1 and 3 wt% clay additive and they begin to biodegrade at the 5th month. However, a composite film of PCL with only 0.4 wt% clay and 5 wt% GMO addition has the shortest degradation time and degraded in 5 months. The films in the last group are; P_G3, P_G5, P_C0.1, P_C0.1_O1, and P_C0.1_O5 and they took around 30 months for biodegradation. It was observed that increasing the organo nanoclay additive increases the biodegradability by disrupting the crystal structure and causing a defective crystal formation. The addition of GMO with organo nano clay also accelerates biodegradation. The addition of organo nano clay in an amount as small as 0.1 wt% acts as the nucleating agent, increases the degree of crystallinity of the PCL composites, and slows the biodegradation period by increasing the time.     

PLA and Organoclays Nanocomposites: Degradation Process and Evaluation of ecotoxicity Using Allium cepa as Test Organism

In this study, nanocomposites of PLA and organoclays Cloisite 20A and Cloisite 30B were prepared by the melt intercalation method and the obtained samples were characterized by transmission electron microscopy (TEM). Since composting is an important proposal to the final disposal of biopolymers, the influence of clays on the hydrolytic degradation process of PLA was evaluated by visual analysis and monitoring of molecular weight after periods of 15 and 30 days of degradation in compost. After degradation of the materials in composting environment, the evaluation of cytotoxic, genotoxic and mutagenic effects of compost aqueous extract was carried out using a bioassay with Allium cepa as test organism. The TEM micrographs permitted the observation of different levels of dispersion, including exfoliated regions. In the evaluation of hydrolytic degradation it was noted that the presence of organoclays can decrease the rate of degradation possibly due to the barrier effect of clay layers and/or the higher degree of crystallinity in the nanocomposite samples. Nevertheless, even in the case of nanocomposites, the molecular weight reduction was significant, indicating that the composting process is favorable to the chain scission of PLA in studied materials. In the analysis performed by the bioassay using A. cepa as test organism, it was found that after degradation of the PLA and its nanocomposites the aqueous extract of compost samples induced a decreasing in the mitotic index and an increasing in the induction of chromosomal abnormalities. These results were statistically significant in relation to the negative control (distilled water). By comparing the results obtained for the nanocomposites in relative to pure polymer, there were no statistically significant differences. The types of the observed chromosomal aberrations indicated a possible genotoxic effect of the materials, which may be related to an aneugenic action of PLA degradation products.     

Biodegradation of Polylactide and Gelatinized Starch Blend Films Under Controlled Soil Burial Conditions

The biodegradability of polylactide (PLA) and gelatinized starches (GS) blend films in the presence of compatibilizer was investigated under controlled soil burial conditions. Various contents (0–40 wt%) of corn and tapioca starches were added as fillers; whereas, different amounts of methylenediphenyl diisocyanate (MDI) (0–2.5 wt%) and 10 wt% based on PLA content of polyethylene glycol 400 (PEG400) were used as a compatibilizer and a plasticizer, respectively. The biodegradation process was followed by measuring changes in the physical appearance, weight loss, morphological studies, and tensile properties of the blend films. The results showed that the presence of small amount of MDI significantly increased the tensile properties of the blends compared with the uncompatibilized blends. This is attributed to an improvement of the interfacial interaction between PLA and GS phases, as evidenced by the morphological results. For soil burial testing, PLA/GS films with lower levels (1.25 wt%) of MDI had less degradation; in contrast, at high level of MDI, their changes of physical appearance and weight loss tended to increase. These effects are in agreement with their water absorption results. Furthermore, biodegradation rates of the films were enhanced with increasing starch contents, while mechanical performances were decreased.     

Study of Thermo-Mechanical and Morphological Behaviour of Biodegradable PLA/PBAT/Layered Silicate Blend Nanocomposites

Poly (lactic acid) (PLA) and poly (butylene adipate-co-terephthalate) (PBAT) blend nanocomposites were prepared using melt blending technique followed by compression moulding. The blend nanocomposites were prepared with a variation of PBAT loading along with maleic anhydride and benzoyl peroxide ranging from 5 to 20 wt% along with two different commercially available nanoclays cloisite 93A and cloisite 30B (C30B) at 3 wt% loading. The maleic anhydride and benzoyl peroxide were used during the melt blending of the blend nanocomposites as a compatibilizer and as an accelerator respectively. Maleic anhydride used to enhance the compatibility of the PLA/PBAT blend and as well as the uniform adhesion of the nanoclays with them. The properties and characterizations of PLA matrix and the PLA/PBAT blend nanocomposites have been studied. The tensile strength, % elongation and impact strength increased with the preparation of PLA/PBAT blend nanocomposites as compared with PLA matrix. PLA/PBAT/C30B blend nanocomposites exhibited optimum tensile strength at 15 wt% of PBAT loading. Differential scanning calorimetry and thermogravimetric analysis also showed improved thermal properties as compared with virgin PLA. The wide angle X-ray diffraction studies indicated an increase in d-spacing in PLA/PBAT/C30B blend nanocomposite thus revealing intercalated morphology.     

Biodegradable Blends with Potential Use in Packaging: A Comparison of PLA/Chitosan and PLA/Cellulose Acetate Films

Poly(lactic acid) (PLA) is a biodegradable polymer that exhibits high elastic modulus, high mechanical strength, and feasible processability. However, high cost and fragility hinder the application of PLA in food packaging. Therefore, this study aimed to develop flexible PLA/acetate and PLA/chitosan films with improved thermal and mechanical properties without the addition of a plasticizer and additive to yield extruder compositions with melt temperatures above those of acetate and chitosan. PLA blends with 10, 20, and 30 wt% of chitosan or cellulose acetate were processed in a twin-screw extruder, and grain pellets were then pressed to form films. PLA/acetate films showed an increase of 30 °C in initial degradation temperature and an increase of 3.9 % in elongation at break. On the other hand, PLA/chitosan films showed improvements in mechanical properties as an increase of 4.7 % in elongation at break. PLA/chitosan film which presented the greatest increase in elongation at break proved to be the best candidate for application in packaging.     

Mechanical Recycling of PLA Filled with a High Level of Cellulose Fibres

Composites consisting of 30 vol% PLA and 70 vol% cellulose fibres were prepared with compression moulding. In the first part of the study, the recyclability of this composite material was investigated by grinding the material and using the recyclate obtained as a filler for PLA. Thus, the recyclate was compounded with PLA in loadings ranging from 20 to 50 wt%. The composites obtained were characterised by tensile tests, Charpy impact tests, DMTA, and SEM. Tests showed that the recyclate had a relatively good reinforcing effect. Stress at break increased from about 50 to 77 MPa and the modulus increased from 3.6 to 8.5 GPa. In the second part of the study, the ability to mechanically recycle the composites obtained was evaluated by repeated processing. Composite with two loadings of the recyclate (20 wt% and 50 %) was injection moulded repeatedly, six times. Tests showed that the composite material with 20 wt% recyclate could withstand six cycles relatively well, while the composite with the higher load degraded much more quickly. For the composites with 50 wt% recyclate, signs of polymer degradation could be seen already after reprocessing the composite once.     

Effect of Hexadecyl Lactate as Plasticizer on the Properties of Poly(<Emphasis Type="SmallCaps">l</Emphasis>-lactide) Films for Food Packaging Applications

In this study, poly(l-lactide) (PLA) films were fabricated by melt processing and the plasticizing effect of hexadecyl lactate (HL) (0, 5, 7.5, 10, and 12.5 wt% on PLA were investigated by scanning electron microscopy (SEM), differential scanning calorimetry, thermogravimetric analysis, tensile, transparency, and water vapor permeability tests. The SEM analysis revealed that PLA with 10 wt% HL appeared uniform with extra small bumps, confirmed the interaction between PLA and HL. The thermal analysis revealed a glass transition temperature of 57.4 °C for neat PLA film, but the addition of HL elicited a decrease in the temperature of the peak (43.8 °C). The incorporation of plasticizer into PLA resulted in the increase of elongation at break, as well as the decrease of tensile strength and tensile modulus. Even though a decrease in transparency was recorded, the PLA/HL blend films appeared transparent by visually observation. The water vapor permeability of PLA/HL blend films increased with the increase of HL. The PLA/HL blend films could effectively extend the shelf-life of fresh-cut pears as the commercial low density polyethylene films. The results indicated that the properties of PLA films can be modified with the addition of HL and PLA/HL blend films could serve as an alternative as food packaging materials to reduce environmental problems associated with synthetic packaging films.     

Mechanical Properties and Isothermal Crystallization Behaviour of Poly(lactide)/Poly(methyl methacrylate)/α-Cellulose Composites

Polylactide (PLA)/polymethylmethacrylate (PMMA)/α-cellulose composites were fabricated using a twin-screw extruder. During fabrication, α-cellulose short fibres were incorporated for improving the toughness of the brittle PLA and a chain extender was used for reducing PLA hydrolysis. Highly transparent PLA and PMMA were blended to obtain miscible and transparent blends. For evaluating the performance of the PLA/PMMA/α-cellulose composites, a series of measurements, including tensile and Izod impact tests, light transmission and haze measurements, thermomechanical analysis, and determination of isothermal crystallisation behaviour, was conducted. Adding the chain extender considerably reduced the occurrence of hydrolytic degradation. Both the chain extender and α-cellulose short fibres increased the elongation at break and Izod impact strength of the composites. Compared with the neat PLA, including 1.0 wt% α-cellulose short fibres increased the elongation at break and Izod impact strength of the composite PLA by approximately 211 and 219 %, respectively. According to the observed mechanical performance, the optimal blending ratios for PLA and PMMA were between 90:10 and 80:20. The total light transmittance of the composites was as high as 91 %, indicating that the PLA/PMMA blend was highly miscible. The haze value of the PLA/PMMA/α-cellulose composites was lower than 32 %. Incorporating cellulose short fibres increased the number of crystallisation sites and crystallinity of the PLA/PMMA/α-cellulose composites while reducing the spherulite dimensions.     

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)/Organomodified Montmorillonite Nanocomposites for Potential Food Packaging Applications

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) is a versatile, biobased and biodegradable copolymer from the family of polyhydroxyalkanoates. This study aims to further ameliorate its properties in order to enhance its applicability for food packaging purposes through preparation of organomodified montmorillonite clay (OMMT) nanocomposites. Nanocomposites based on pure PHBHHx as well as commercial PHBHHx granulate, after a previous dry-mixing with OMMT in concentrations of 1, 3, 5 and 10 wt%, were prepared using melt blending and compression molding. Investigation of the samples showed well dispersed nanofiller and highly intercalated nanocomposites, resulting in a continuous decrease in gas permeability, lowering O₂, CO₂ and water vapor permeability with about 5–7 % and approximately 40 % at OMMT concentration of 1 and 10 wt%, respectively. Besides gas permeability, other properties were affected as well. Thermal stability of the samples increased gradually up to 5 wt% nanofiller, but was reduced at 10 wt%. In order to investigate the effects of OMMT and molecular weights on PHBHHx crystallization, nanocomposites were also produced by solvent-casting and compared to those obtained by melt-blending. Crystallization was retarded, because of severe lowering of molecular weight due to processing-induced chain scission, catalyzed by OMMT moisture. However, this reduction was counteracted for a large part by using commercial PHBHHx granulate, which has shown better crystallization properties. The samples were rendered increasingly more brittle, displaying higher Young’s modulus and severely reduced elongation at break. From this study it appeared that, upon viewing all affected properties as a whole, the sample based on commercial PHBHHx and containing 3 wt% OMMT shows most promise for possible applications, however further research must be performed in order to exploit their fullest potential.     

Stiff Biodegradable Polylactide Composites with Ultrafine Cellulose Filler

Polylactide (PLA) composites with 10–30 wt% of commercial fine grain filler of native cellulose were prepared by melt-mixing, and examined. The composite films had esthetic appearance, glossy surface, creamy color and density close to that of neat PLA. Good dispersion of the filler in PLA matrix was achieved. The composites were stiffer than neat PLA; in the glassy region the storage modulus increased by approx. 30 %. The tensile strength of the composite materials in the temperature range from 25 to 45 °C was similar to that of neat PLA. No marked decrease in molar mass of PLA in the composites occurred during processing in comparison to neat PLA. Moreover, thermogravimetry experiments demonstrated good thermal stability of the composites; 5 % weight loss occurred well above 300 °C.     

Fabrication and Characterization of PLA/PHBV-Chitin Nanocomposites and Their Foams

This paper examines the effect of biobased chitin nanowhisker fillers on the thermal, rheological, physical, mechanical and morphological properties of biobased polylactic acid (PLA) and PLA/polyhydroxybutyrate-co-valerate (PHBV) blended nanocomposites as well as the physical, mechanical and morphological properties of porous PLA and PLA/PHBV nanocomposite foams. Solid nanocomposites of PLA, PLA/PHBV and chitin nanowhiskers were manufactured through melt blending while porous nanocomposites foams were fabricated through a batch foaming process with the aid of CO₂ as blowing agent. It was found that by incorporating small quantities of chitin nanowhiskers (<2 wt%) the mechanical properties of solid specimens are improved while strength and expandability of the foam can be significantly improved, yielding a homogenously distributed cell morphology with average cell size of 1.5 μm.     

Polyhydroxybutyrate-Based Nanocomposites with Cellulose Nanocrystals and Bacterial Cellulose

Polyhydroxybutyrate (PHB) films nanoreinforced with hydrolyzed cellulose nanocrystals (CNC) and bacterial cellulose (BC) were prepared by solvent casting. The influence of different cellulose nanoparticles content (2, 4 and 6 wt% of CNC and 2 wt% of BC) on the PHB properties was studied. CNC nanocomposites presented good dispersion of the nanocrystals, improving transparency, mechanical and barrier properties of the PHB films. On the other hand, reduced thermal stability and mechanical properties were yielded by BC addition due to the intrinsic lower degradation temperature and higher length of the BC nanofibrils compared to CNC. Nanocomposites performance variation is mainly caused by the marked difference in nanoparticles structure. It was demonstrated that PHB–CNC films exhibited higher performance enhancement without detrimental effect of the pristine PHB properties.     

Thermocatalytic Degradation of High Density Polyethylene into Liquid Product

Thermocatalytic degradation of high density polyethylene (HDPE) was carried out using acid activated fire clay catalyst in a semi batch reactor. Thermal pyrolysis was performed in the temperature range of 420–500 °C. The liquid and gaseous yields were increased with increase in temperature. The liquid yield was obtained 30.1 wt% with thermal pyrolysis at temperature of 450 °C, which increased to 41.4 wt% with catalytic pyrolysis using acid activated fire clay catalyst at 10 wt% of catalyst loading. The composition of liquid products obtained by thermal and catalytic pyrolysis was analyzed by gas chromatography-mass spectrometry and compounds identified for catalytic pyrolysis were mainly paraffins and olefins with carbon number range of C₆–C₁₈. The boiling point was found in the range of commercial fuels (gasoline, diesel) and the calorific value was calculated to be 42 MJ/kg.     

Processing Stability and Biodegradation of Polylactic Acid (PLA) Composites Reinforced with Cotton Linters or Maple Hardwood Fibres

Polylactic acid (PLA) composites comprising up to 25 wt% cotton linter (CL) or up to 50 % maple wood fibre (WF) were prepared by compounding and injection moulding. A reduction of crystallinity in the PLA matrix was observed as a result of the thermal processing method. These PLACL and PLAWF composites provided excellent improvements in both stiffness (with increases in tensile and flexural modulus) and toughness (increases in notched impact strength) properties over the neat PLA resin, while the tensile and flexural strengths of the composites were generally unchanged, while the strain at break values were reduced in comparison to the neat PLA. DMA results indicated incorporating these fibres caused the mechanical loss factor (tan δ) to decrease, suggesting better damping capabilities were achieved with the composites. SEM analysis of the impact fractured surfaces of the PLACL composites showed debonding-cavitation at the matrix-fibre interface while the PLAWF composites showed good wetting along its matrix-fibre interface. The composting of these composites up to 90 days showed that the degradation onset time was increased when increasing the fibre loadings, but the maximum degree of degradation and the maximum daily rates of degradation were decreased compared to neat PLA. On a weight basis of fibre loading, the PLACL composites had a quicker onset of biodegradation, a higher maximum daily rate of biodegradation and, overall, a higher degree of biodegradation at 90 days than the PLAWF composites, possibly due to the quicker thermal hydrolysis observed in the PLA matrix of the PLACL composites during processing and composting.     

Novel Tough Crystalline Blends of Polylactide with Ethylene Glycol Derivative of POSS

Blending of polylactide (PLA) with low stereoregularity and polyhedral oligomeric silsesquioxane grafted with arms of poly(ethylene glycol) methyl ether, acting as a plasticizer, allowed us previously to obtain a novel stable elastomeric-like material. The present contribution focuses on the properties of semi-crystalline PLA plasticized with this compound. Melt blends of PLA with 5–15 wt% of the plasticizer, were compression molded, quenched and annealed, which enabled cold-crystallization. The glass transition temperature of the blends and their drawability depended on their crystallinity and plasticizer content. The best ductility was reached at the plasticizer content of 15 wt%; the achieved strain at break was 6.5 (650%) and 1.3 (130%), for the quenched and annealed material, respectively. The latter value exceeded 20 times the strain at break of neat crystalline PLA. The tensile toughness of the annealed 15 wt% blend was 12 times larger than that of crystalline PLA. Moreover, annealing of 15 wt% blend improved its yield strength by 40%. Despite the two peaks of the loss modulus, indicating the two glass transitions in this blend, no heterogeneities were found by scanning electron microscopy, indicating that the plasticizer enriched phase formed instead of distinct inclusions of the plasticizer.     

Fabrication of Admicelled Natural Rubber by Polycaprolactone for Toughening Poly(lactic acid)

Natural rubber (NR) with polycaprolactone (PCL) core–shell (NR-ad-PCL), synthesized by admicellar polymerization, was acted as an impact modifier for poly(lactic acid) (PLA). PLA and NR-ad-PCL were melt-blended using a co-rotating twin screw extruder. The morphology of PLA/NR-ad-PCL blends showed good adhesion as smooth boundary around rubber particles and PLA matrix. Only 5 wt% of rubber phase, NR-ad-PCL was more effective than NR to enhance toughness and mechanical properties of PLA. The contents of the NR-ad-PCL were varied from 5, 10, 15 and 20 wt%. From thermal results, the incorporation of the NR-ad-PCL decreased the glass transition temperature and slightly increased degree of crystallinity of PLA. Mechanical properties of the PLA/NR-ad-PCL blends were investigated by dynamic mechanical analyser, pendulum impact tester and universal testing machine for tension and flexural properties. The increasing NR-ad-PCL contents led to decreasing Young’s and storage moduli but increasing loss modulus. Impact strength and elongation at break of the PLA/NR-ad-PCL blends increased with increasing NR-ad-PCL content up to 15 wt% where the maximum impact strength was about three times higher than that of pure PLA and the elongation at break increased to 79%.     

The Effect of Gamma and Electron Beam Irradiation on the Biodegradability of PLA Films

Biodegradation of poly(lactic) acid (PLA) has been studied extensively, but there is only limited knowledge about the effect of irradiation sterilization on its biodegradability. The aim of this work was to examine the aerobic biodegradation of gamma and electron beam irradiated PLA films along with the effects of aging (3, 6, and 9 months of storage) using a direct measurement respirometric system. Commercial PLA film was exposed to a simulated aerobic compost environment, and its mineralization was 96 % at day 85. Gamma and electron beam irradiation affected the biodegradation of the post-irradiated PLA film. Aging irradiated PLA had some potential to increase the biodegradation rate, as the average value of mineralization after 9 months of storage was higher than for the non-irradiated PLA. Comparison of the effect of storage time on the biodegradability of PLA showed a significant increase in biodegradation of the gamma irradiated PLA after 3 months (70 %) and 9 months of storage (130 %). Similarly, there was a significant difference in the biodegradation of electron beam irradiated PLA between 3 months (68 %) and 9 months of storage (120 %). Due to the priming effect, the percent mineralization of gamma irradiated and E-beam irradiated PLA after 9 months of storage was greater than 100 %. Both non-irradiated and irradiated PLA films can be considered biodegradable plastics since they showed mineralization percentage larger than 90 % of that of the positive control at the end of the test period.     

Green Composites of Poly (Lactic Acid) and Sugarcane Bagasse Residues from Bio-refinery Processes

Twin-screw extrusion was used to prepare the composites consisting of PLA and three types of sugarcane bagasse residues (up to 30 wt%) derived from different steps of a biorefinery process. Each residue had different composition, particle size and surface reactivity due to chemical and biological (enzyme, microbes) treatments that the biomass was subjected to. The effects of different residue characteristics on properties, crystallization behaviors and morphologies of PLA composites were investigated. Besides, a small amount (2 wt%) of coupling agent, Desmodur^® VKS 20 (DVKS), was used to improve the interfacial bonding between PLA and bagasse residues. The results indicated that in the presence of 2 % DVKS, PLA composite with pretreated residue exhibited the maximum strength properties (98.94 % tensile strength and 93.91 % flexural strength of neat PLA), while PLA composite with fermentation residue exhibited the minimum strength properties (88.98 % tensile strength and 81.91 % flexural strength of neat PLA).     

Grafting of Glycidyl Methacrylate onto Poly(lactide) and Properties of PLA/Starch Blends Compatibilized by the Grafted Copolymer

Poly(lactide)-graft-glycidyl methacrylate (PLA-g-GMA) copolymer was prepared by grafting GMA onto PLA in a batch mixer using benzoyl peroxide as an initiator. The graft content was determined with the ¹H-NMR spectroscopy by calculating the relative area of the characteristic peaks of PLA and GMA. The result shows that the graft content increases from 1.8 to 11.0 wt% as the GMA concentration in the feed varies from 5 to 20 wt%. The PLA/starch blends were prepared by the PLA-g-GMA copolymer as a compatibilizer, and the structure and properties of PLA/starch blends with or without the PLA-g-GMA copolymer were characterized by SEM, DSC, tensile test and medium resistance test. The result shows that the PLA/starch blends without the PLA-g-GMA copolymer show a poor interfacial adhesion and the starch granules are clearly observed, nevertheless the starch granules are better dispersed and covered by PLA when the PLA-g-GMA copolymer as a compatibilizer. The mechanical properties of the PLA/starch blends with the PLA-g-GMA copolymer are obviously improved, such as tensile strength at break increasing from 18.6 ± 3.8 MPa to 29.3 ± 5.8 MPa, tensile modulus from 510 ± 62 MPa to 901 ± 62 MPa and elongation at break from 1.8 ± 0.4 % to 3.4 ± 0.6 %, respectively, for without the PLA-g-GMA copolymer. In addition, the medium resistance of PLA/starch blends with the PLA-g-GMA copolymer was much better than PLA/starch blends.     

Study on the Effect of Dicumyl Peroxide on Structure and Properties of Poly(Lactic Acid)/Natural Rubber Blend

In attempt to enhance the compatibility of NR in PLA matrix, and furthermore to enhance mechanical properties of PLA, PLA/NR blends with strong interaction were prepared in Haake internal mixer, using dicumyl peroxide (DCP) as cross-linker. The effects of dicumyl peroxide on morphology, thermal properties, mechanical properties and rheological properties of PLA and PLA/NR blends were studied. The results indicated that dicumyl peroxide could increase the compatibility of poly(lactic acid) and natural rubber. With small amount of dicumyl peroxide, the effect on NR toughening PLA was enhanced and the tensile toughness of PLA/NR blends was improved. When the DCP content was up to 0.2 wt%, the PLA/NR blend reached the maximum elongation at break (26.21 %) which was 2.5 times of that of neat PLA (the elongation at break of neat PLA was 10.7 %). Meanwhile, with introducing 2 wt% DCP into PLA/NR blend, the maximum Charpy impact strength (7.36 kJ/m²) could be achieved which was 1.8 times of that of neat PLA (4.18 kJ/m²). Moreover, adding adequate amount of DCP could improve the processing properties of blends: the viscosity of PLA/NR blend decreased significantly and the lowest viscosity of the blends could be achieved when the DCP content was 0.5 wt%.