On the use of ball milling to develop poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate)‐graphene nanocomposites (II)—Mechanical,barrier, and electrical properties

In this work, poly (3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) nanocomposites containing functionalized graphene sheets (FGS) were prepared by means of high‐energy ball milling. The crystalline structure, oxygen barrier, mechanical and electrical properties, and biodegradability of the developed nanocomposites were analyzed and correlated with the amount of FGS incorporated and with their morphology, which was reported in a previous study. Addition of FGS into the PHBV matrix did not affect the crystal morphology of the material but led to somewhat enhanced crystallinity. The good dispersion and distribution of the nanofiller within the polymeric matrix, revealed in the first part of this study, was thought to be crucial for the mechanical reinforcing effect of FGS and also resulted in enhanced gas barrier properties at high relative humidity. Additionally, the conducting behavior of the nanocomposites, as interpreted by the percolation theory, displayed a very low percolation threshold set at ～0.3 vol % of FGS, while the materials exhibited an overall significantly enhanced conductivity. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42217.     

Preparation and properties of acrylonitrile–butadiene rubber–graphene nanocomposites

The graphene oxide (GO) was prepared by sonication‐induced exfoliation from graphite oxide, which was produced by oxidation from graphite flakes with a modified Hummer's method. The GO was then treated by hydrazine to obtain reduced graphene oxide (rGO). On the basis of the characterization results, the GO was successfully reduced to rGO. Acrylonitrile–butadiene rubber (NBR)–GO and NBR–rGO composites were prepared via a solution‐mixing method, and their various physical properties were investigated. The NBR–rGO nanocomposite demonstrated a higher curing efficiency and a change in torque compared to the gum and NBR–GO compounds. This agreed well with the crosslinking density measured by swelling. The results manifested in the high hardness (Shore A) and high tensile modulus of the NBR–rGO compounds. For instance, the tensile modulus at a 0.1‐phr rGO loading greatly increased above 83, 114, and 116% at strain levels of 50, 100, and 200%, respectively, compared to the 0.1‐phr GO loaded sample. The observed enhancement was highly attributed to a homogeneous dispersion of rGO within the NBR matrix; this was confirmed by scanning electron microscopy and transmission electron microscopy analysis. However, in view of the high ultimate tensile strength, the NBR–GO compounds exhibited an advantage; this was presumably due to strong hydrogen bonding or polar–polar interactions between the NBR and GO sheets. This interfacial interaction between GO and NBR was supported by the marginal increase in the glass‐transition temperatures of the NBR compounds containing fillers. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42457.     

Multilayer coextrusion of graphene polymer nanocomposites with enhanced structural organization and properties

A potential advantage of platelet‐like nanofillers as nanocomposite reinforcements is the possibility of achieving two‐dimensional (2D) stiffening through planar orientation of the platelets. Forced assembly by multilayer coextrusion, which enables the in‐plane orientation of platelet‐like fillers in alternating layers, was used in this work to produce poly(lactic acid) (PLA)/graphene multilayer films. These films exhibited a multilayer structure made of alternating layers of neat PLA and PLA containing graphite nanoplatelets (GNPs). Electron microscopy revealed information on the orientation of the individual GNPs. X‐ray diffraction results indicated that the thickness of the individual GNPs was reduced during the multilayer coextrusion process. A significant reinforcement of 120% at an overall GNP loading of 1 wt % in PLA was achieved. This high effective reinforcement was attributed to the high degree of planar alignment, improved dispersion and exfoliation and increased aspect ratio of the GNPs in the composite layers after multilayer coextrusion. Improved water vapor barrier properties were also achieved as a result of the highly organized 2D nanofillers in the multilayer films. These industrial scalable multilayer nanocomposite films open up possibilities for lightweight and strong packaging materials for food and industrial applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46041.     

Influence of rubber content on mechanical,thermal, and morphological behavior of natural rubber toughened poly(lactic acid)–multiwalled carbon nanotube nanocomposites

The effects of natural rubber (NR) on the mechanical, thermal, and morphological properties of multiwalled carbon nanotube (CNT) reinforced poly(lactic acid) (PLA) nanocomposites prepared by melt blending were investigated. A PLA/NR blend and PLA/CNT nanocomposites were also produced for comparison. The tensile strength and Young's modulus of PLA/CNT nanocomposites improved significantly, whereas the impact strength decreased compared to neat PLA. The incorporation of NR into PLA/CNT significantly improved the impact strength and elongation at break of the nanocomposites, which showed approximately 200% and 850% increases at 20 wt % NR, respectively. However, the tensile strength and Young's modulus of PLA/NR/CNT nanocomposites decreased compared to PLA/CNT nanocomposites. The morphology analysis showed the homogeneous dispersion of NR particles in PLA/NR/CNT nanocomposites, while CNTs preferentially reside in the NR phase rather than the PLA matrix. In addition, the incorporation of NR into PLA/CNT lowered the thermal stability and glass‐transition temperature of the nanocomposites. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44344.     

Assessment of ball milling methodology to develop polylactide‐bacterial cellulose nanocrystals nanocomposites

In this work, ball milling is evaluated as a methodology to develop polylactide (PLA)‐bacterial cellulose nanocrystals (BCNC) nanocomposites. This technique, widely used for clay‐based nanocomposites, is effective in breaking up to a very large extent the freeze‐dried nanocellulose aggregates, giving raise to transparent films similar to the neat PLA films. Incorporation of the nanofiller through this methodology enhances the polymer crystallinity index. An increase in the onset degradation temperature and a significant reinforcing effect in terms of an increase in the storage modulus and in the tan delta peak are also observed. Improved barrier to oxygen at high relative humidity (80%) is also noticed, reaching the best performance at the lowest BCNC loading (0.5 wt %). These improvements are related to the relatively good nanocellulose dispersion and distribution attained for low loadings of the nanofiller. Thus, the ball milling methodology appears as a feasible processing methodology for developing PLA‐BCNC nanocomposites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41605.     

The preparation,characterization, and properties of silver nanoparticle reinforced reduced graphene oxide–poly(amidoamine) nanocomposites

A simple approach was employed to synthesize silver nanoparticle (Ag NP) reinforced reduced graphene oxide–poly(amidoamine) (Ag‐r‐RGO–PAMAM) nanocomposites. The structural changes of the nanocomposites with the PAMAM and Ag NPs were confirmed by Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, X‐ray diffraction, Raman spectroscopy, and scanning electron microscopy. In addition, the performance was characterized with thermogravimetric and electrical conductivity instruments. The results indicate that the Ag NPs are well dispersed in fine size on the surface of the RGO–PAMAM composites, which results in an increase of at least 38% in thermostability and a certain enhancement in electrical conductivity. It is worth noting that the electrical conductivity of the nanocomposites was approximately 5.88 S cm^?1, which was higher than that of RGO–PAMAM, and increases with the rising content of silver nanoparticles. Meanwhile, the Ag‐r‐RGO–PAMAM nanocomposites still maintain a favorable dispersion in organic solvents. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45172.     

Fully bio‐based poly(ɛ‐capolactone)/poly(lactide) alternating multiblock supramolecular polymers: Synthesis,crystallization behavior,and properties

Supramolecular poly(?‐capolactone)/poly(lactide) alternating multiblock copolymers were prepared by UPy‐functionalized poly(lactide)‐b‐ poly(?‐capolactone)‐b‐ poly(lactide) copolymers. The prepared supramolecular polymers (SMPs) exhibit the characteristic properties of thermoplastic elastomers. The stereo multiblock SMPs (sc‐SMPs) were formed by blending UPy‐functionalized poly(l ‐lactide)‐b‐ PCL‐b‐ poly(l ‐lactide) (l ‐SMPs) and UPy‐functionalized poly(d ‐lactide)‐b‐ PCL‐b‐ poly(d ‐lactide) (d ‐SMPs) due to stereocomplexation of the PLLA and PDLA blocks. Sc‐SMPs with low content of d ‐SMPs (≤20%) are transparent, elastic solids, while those having high d ‐SMPs content are opaque, brittle solids. The effects of l ‐SMPs/d ‐SMPs mixing ratios on thermal, crystallization behaviors, crystal structure, mechanical and hydrophilic properties of sc‐SMPs were deeply investigated. The incorporation of UPy groups depresses the crystallization of polymer, and the stereocomplex formation accelerates the crystallization rate. The used initiator functionalized polyhedral oligomeric silsesquioxanes causes a different effect on the crystallization of PLA and PCL blocks. The tensile strength and elongation at break of l _d /d _d ‐SMPs (d represents the initiator diethylene glycol) are significantly larger than that of l _p /d _p ‐SMPs (p represents the initiator polyhedral oligomeric silsesquioxanes), and their heat resistance and hydrophilicity can be also modulated by the l ‐SMPs/d ‐SMPs mixing ratios and the different initiators. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45575.     

In situ polymerization of bio‐based thermosetting polyurethane/graphene oxide nanocomposites

Novel bio‐based polyurethane/graphene oxide (GO) nanocomposites have been successfully synthesized from biorenewable epoxidized soybean‐castor oil fatty acid‐based polyols with considerable improvement in mechanical and thermal properties. The GO was synthesized via a modified pressurized oxidation method, and was investigated using Raman spectra, AFM and XPS, respectively. The toughening mechanism of GO in the bio‐based polyurethane matrix was explored. The elongation at break and toughness of polyurethane were increased by 1.3 and 0.8 times with incorporation of 0.4 wt % GO, respectively. However, insignificant changes in both mechanical strength and modulus were observed by adding GO. The results from thermal analysis indicated that the GO acts as new secondary soft segments in the polyurethane which lead to a considerable decrease in the glass transition temperature and crosslink density. The SEM morphology of the fracture surface after tensile testing showed a considerable aggregation of graphene oxide at concentrations above 0.4 wt %. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41751.     

Comparison of covalent and noncovalent interactions of carbon nanotubes on the crystallization behavior and thermal properties of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate)

In this study, multiwalled carbon nanotubes (MWCNTs) were dispersed into a poly(3‐hydroxybutyrate‐co?3‐hydroxyvalerate) (PHBV) matrix, in which PHBV was either covalently attached to the nanotubes through an esterification reaction between the carboxylic groups of functionalized MWCNTs and the hydroxyl groups of PHBV with toluene diisocyanate as a coupling agent or physically mixed to result in only noncovalent interactions. The structure, crystallization behavior, and thermal properties of the resulting nanocomposites were studied. We found that the crystallization of PHBV grafted onto the MWCNTs (PHBV‐g‐MWCNTs) was markedly hindered and exhibited an exothermic peak caused by cold crystallization, whereas the nonisothermal crystallization of PHBV was enhanced because a heterogeneous nucleation effect appeared in the PHBV/MWCNTs. Moreover, the maximum decomposition temperature of the PHBV‐g‐MWCNTs was improved by about 14.4°C compared with that of the PHBV/MWCNTs and by about 23.7°C compared with that of the original PHBV. Furthermore, the PHBV‐g‐MWCNTs exhibited the wider melt‐processing window than the PHBV/MWCNTs and original PHBV. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4299–4307, 2013     

Influence of silanized low‐dimensional carbon nanofillers on mechanical,thermomechanical, and crystallization behaviors of poly(L‐lactic acid) composites—A comparative study

Composites were investigated regarding the comparison of multi‐walled carbon nanotubes (MWCNTs) with exfoliated graphene(EG) in poly(L‐lactic acid) (PLLA) and the effect of silane‐treated carbon nanofillers on properties of PLLA composites. Solution blending method was used to prepare PLLA composites at a filler content of 0.5 wt %. Fourier transform infrared spectroscopy and X‐ray photoelectron spectra results indicated the attachment of silane molecules on the surface of these nanofillers. It was found that the addition of these nanofillers greatly enhanced the mechanical, thermomechanical, and crystallization behaviors of PLLA due to the heterogeneous nucleation effect. Moreover, the silane‐treated fillers further enhanced the breaking elongation moderately (although the materials are still brittle), modulus and thermal property of the nanocomposites, without sacrificing the tensile strength, compared with the pristine nanocomposites. On the other hand, composites reinforced with MWCNTs and EG perform almost the same mechanical property. And EG outperformed MWCNTs in thermomechanical properties of composites when being used as the reinforcement of PLLA. Conversely, composites reinforced with MWCNTs showed better crystallization properties than those reinforced with EG. Interestingly, no significant changes were observed for the crystallization properties of PLLA composites when MWCNTs and EG had been treated by silane coupling agent. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1194‐1202, 2013     

Recent advances in bio‐sourced polymeric carbohydrate/nanotube composites

Nanotubes (NTs), especially carbon nanotubes (CNTs), have attracted much attention in recent years because of their large specific surface area, and their outstanding mechanical, thermal, and electrical properties. In this review we emphasize the development of fascinating properties of polymeric carbohydrate/CNT composites, particularly in terms of their mechanical and conductivity properties and potential applications. Many methods used to modify CNTs during preparation of polymeric carbohydrate/CNT composites are presented. Moreover, we also discuss the enhanced mechanical and electrical effectiveness when hybrid CNTs or halloysite nanotubes were incorporated into different carbohydrate polymer matrices. Finally, we give a future outlook for the development of polymeric carbohydrate/CNT composites as potential alternative materials for various applications including sensors, electroactive paper, electrodes, sorbents for environmental remediation, packaging film, specialty textile, and biomedical devices. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40359.     

Dynamic mechanical thermal analysis of biocomposites based on PLA and PHBV—A comparative study to PP counterparts

The primary objective of this study was the investigation of thermo‐mechanical behavior of cellulosic fiber reinforced polylactid (PLA) and poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) biopolymers. Both PLA and PHBV were processed with 30 wt % of cellulosic fibers; moreover, to improve the processability and mechanical performance, PHBV was previously blended with 30% by weight poly(butylene adipate‐co‐butylene terephthalate) (PBAT). Secondary target was the comparison of the obtained results to natural fiber reinforced polypropylene (PP) composites reinforced with exact the same fibers and processed by using identical techniques. For validation the thermo‐mechanical properties, a dynamic mechanical thermal analysis (DMTA) was applied. Storage modulus (E′), loss modulus (E″), and loss factor (tan δ) were determined. The DMTA results indicate decreased polymer chain motion with resulting improvement of stiffness expressed by the storage modulus. Finally, the effectiveness of fiber on the moduli was investigated. The C coefficient differs in dependence on fiber type, use of coupling agent, and the reference temperature in glassy state. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3175–3183, 2013     

Thermal,electrical, and dielectric properties of reduced graphene oxide–polyaniline nanotubes hybrid nanocomposites synthesized by in situ reduction and varying graphene oxide concentration

In this study, reduced graphene oxide (RGO) has been introduced as conductive filler within polyaniline (PAni) nanotubes (PAniNTs) by in situ chemical reduction method to enhance the properties of PAniNTs. The effect of varied concentration of in situ reduced GO on the structural, thermal, electrical, and dielectric properties of RGO–PAniNTs nanocomposites have been investigated by high resolution transmission electron microscope, X‐ray diffraction, Fourier transform infrared, thermogravimetric analysis, I–V characteristics, and impedance analyzer. The enhanced thermal stability of the nanocomposites has been analyzed from the derivative thermogravimetric curves in terms of onset and rapid decomposition temperature. The transport mechanisms have been studied by fitting the nonlinear I–V characteristics to the Kaiser model. The dielectric relaxation phenomena have been investigated by permittivity and modulus formalisms. Characteristic relaxation frequency of RGO–PAniNTs nanocomposites shifts toward higher frequency with increasing RGO concentration indicating a distribution in conductivity relaxation. The distribution of relaxation time has been studied by fitting the imaginary modulus spectra of the nanocomposites to Bergman modified KWW function. The ac conductivity spectra are fitted to the Jonscher's power law equation and enhanced conductivity value of 1.26 × 10⁻³ S cm⁻¹ is obtained for 40 wt % of RGO compared to 1.22 × 10⁻⁴ S cm⁻¹ for PAniNTs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45883.     

Sustainable biodegradable coffee grounds filler and its effect on the hydrophobicity,mechanical and thermal properties of biodegradable PBAT composites

Poly(butylene adipate‐co‐terephthalate) (PBAT) and coffee grounds (CG) wastes are biodegradable materials. The high cost of PBAT restricts its marketability; the lignocellulosic CG were used as a reinforcing agent for PBAT. Thus, the present work focuses mainly on the preparation and characterization of bio‐based PBAT composites filled with CG bio‐additives with affordable cost, and with potential use in a variety of eco‐friendly fields such as packaging, biomedical devices, and composting. The PBAT polymer was melt blended with various contents of CG powder using twin screw extrusion. The compatibility and dispersion state of investigated biocomposites in presence or absence of PEG as plasticizer were investigated by using scanning electron microscopy (SEM) and X‐ray diffraction (XRD). The effect of the addition of PEG on PBAT/CG was characterized by differential scanning calorimetry (DSC), tensile properties, contact angle measurements, and thermogravimetric analysis. The chemical interaction between hydroxyl groups of CG particles and PEG plasticizer was achieved by these techniques. A pyrolysis kinetic model was proposed to identify the kinetic parameters of the thermal degradation of PBAT and CG powder. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44498.     

Poly(glycerol–sebacate) bioelastomers—kinetics of step‐growth reactions using Fourier Transform (FT)‐Raman spectroscopy

Kinetic studies of the esterification of glycerol (G) and sebacic acid (SA) at three molar ratios (0.6, 0.8, 1.0) and at three temperatures (120, 130, 140°C) to form poly(glycerol–sebacate) were performed and assessed using FT‐Raman spectroscopy. The quantitative changes in the concentrations of carboxylic acid and ester groups within the forming bioelastomer were measured and the chemical rate constants (k) determined from the kinetic scheme were first‐order, with respect to sebacic acid concentration. Increasing the reaction temperature by 20°C is noted to increase the chemical rate constant (k) by a factor of up to 4.5 and the total extent of conversion at early times for the molar ratios investigated. The activation energy (E_a) and the pre‐exponential factor (A₀) for these three stoichiometric ratios were calculated, which varied in accordance with the average functionality of the system. Under isothermal conditions, the chemical rate constant remained unchanged with an increase in the extent of the reaction (α) until a spontaneous transition resulted in the shift in the mechanism from kinetics to diffusion controlled. The Young's moduli of the PGS polymers were found to depend primarily on the average functionality of the system and the curing period. This investigation confirms the reaction mechanism for PGS polymer synthesis and shows the flexibility afforded to PGS properties and reaction times through varying the stoichiometric ratios of glycerol to sebacic acid. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effect of five saturated fatty acids on the properties of sweet‐potato‐starch‐based films

To fully explore the influences of saturated fatty acids (SFAs) on the properties of sweet‐potato‐starch (SPS)‐based films, five SFAs were chosen to add to SPS. The SPS‐based films were prepared by casting. The microstructure, mechanical, optical, water vapor barrier, and thermal properties of the films were investigated. The 2.0% (w/w, on the basis of starch) SFA significantly changed the SPS pasting characteristics in the peak viscosity, breakdown, and other feature point viscosity values as determined by a Rapid Visco Analyser. The amylose molecular weights decreased as measured by high‐performance size exclusion chromatography. A thermal study with differential scanning calorimetry suggested that the addition of SFA increased the onset temperature and peak temperature. Scanning electronic microscope (SEM) images showed a continuous and uniform structure in the films with SFA. The SPS–SFA composite films showed lower light transmission and elongation at break than the control. Compared with the control films, the addition of SFA increased the tensile strength and decreased the water vapor permeability of the films. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41380.     

Effectiveness of the preparation of maleic anhydride grafted poly (lactic acid) by reactive processing for poly (lactic acid)/carbon nanotubes nanocomposites

An effective strategy to increase the properties of poly (lactic acid) (PLA) is the addition of carbon nanotubes (CNT). In this work, aiming to improve the surface adhesion of PLA and CNT a new compatibilizer agent was prepared by reactive processing, PLA grafted maleic anhydride (PLA-g-MA) using benzoyl peroxide and maleic anhydride. The effectiveness of the PLA-g-MA as a compatibilizer agent was verified for PLA/PLA-g-MA/CNT nanocomposites. PLA and PLA-g-MA samples were characterized by Fourier transform infrared spectroscopy (FT-IR) to confirm the grafting reaction of maleic anhydride on PLA chains and by rheological analysis to prove the changes in the matrix PLA after the graphitization reaction. Thermal (differential scanning calorimetry and thermogravimetric analysis), mechanical tests (Izod impact strength and tensile test), and morphological characterization were used to verify the effect of the compatibilizer agent. The preparation of PLA-g-MA by reactive extrusion processing proved satisfactory and the nanocomposites presented good thermal and mechanical properties. The addition of the PLA-g-MA also contributed to the greater distribution of CNT and can be used as an alternative for the production of PLA/CNT nanocomposites.     

Nanocomposites of ethylene vinyl alcohol copolymer with thermally resistant cellulose nanowhiskers by melt compounding (I): Morphology and thermal properties

In this study, ethylene‐vinyl alcohol copolymer (EVOH) nanocomposites were prepared by melt compounding both plant cellulose nanowhiskers (CNW) and bacterial cellulose nanowhiskers (BCNW) as nanofillers. Electrospinning and a “dissolution precipitation” method were used as strategies for the incorporation of CNW in EVOH before melt compounding with the aim of enhancing the degree of dispersion of the nanocrystals when compared with direct melt‐mixing of the freeze‐dried product with the polymer. As revealed by morphological characterization, the proposed preincorporation methods led to a significant improvement in the dispersion of the nanofiller in the final nanocomposite films. Furthermore, it was possible to incorporate concentrations as high as 4 wt % BCNW without causing significant agglomeration of the nanofiller, whereas increasing the CNW concentration up to 3 wt % induced agglomeration. Finally, DSC studies indicated that the crystalline content was significantly reduced when the incorporation method led to a poor dispersion of the nanocrystals, whereas high‐nanofiller dispersion resulted in thermal properties similar to those of the neat EVOH. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Fabrication of mPEGylated graphene oxide/poly(2‐dimethyl aminoethyl methacrylate) nanohybrids and their primary application for small interfering RNA delivery

Graphene oxide (GO)‐based nanohybrids were designed for small interfering RNA (siRNA) delivery for their high water dispensability, good biocompatibility, easily tunable surface functionalization, and particular optical properties. In this study, novel nanohybrids based on GO were fabricated. Methoxypoly(ethylene glycol) (mPEG) was covalently conjugated to GO via amide bonds. Then, poly(2‐dimethyl aminoethyl methacrylate) (PDMAEMA), which was synthesized via reversible addition–fragmentation chain transfer polymerization (RAFT) with 2‐(dodecyl thiocarbonothioyl thio)‐2‐methyl propionic acid (DTM) as the RAFT agent, was attached onto GO via physical interaction between DTM and GO. Compared with Lipofectamine 2000, the novel mPEG–GO/PDMAEMA nanohybrids showed comparable gene transfection efficiency and a low cytotoxicity. Moreover, the mPEG–GO/PDMAEMA nanohybrids showed enhanced optical properties compared to the original GO because of the presence of mPEG and PDMAEMA. Our work encouraged further exploration of the novel nanovector for combined photothermal and siRNA delivery. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43303.     

Synergistic reinforcing of poly(lactic acid) by poly(butylene adipate-co-terephthalate) and alumina nanoparticles

Biodegradable poly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blends and PLA/PBAT/Al₂O₃ nanocomposites were fabricated via solution blending. The influence of PBAT and Al₂O₃ content on the thermal stability, flexural properties, impact strength, and morphology of both the PLA/PBAT blends and the PLA/PBAT/Al₂O₃ nanocomposites were investigated. The impact strength of the PLA/PBAT/Al₂O₃ nanocomposites containing 5 wt% PBAT increased from 4.3 to 5.2 kJ/m² when the Al₂O₃ content increased from 0 to 1 wt%. This represents a 62% increase compared to the impact strength of pristine PLA and a 20% increase compared to the impact strength of PLA/PBAT blends containing 5 wt% PBAT. Scanning electron microscopy imaging revealed that the Al₂O₃ nanoparticles in the PLA/PBAT/Al₂O₃ nanocomposites function as a compatibilizer to improve the interfacial interaction between the PBAT and the PLA matrix.