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The rapid evolution of 3D‐printing (3DP) technologies has generated scope of developing advanced feedstock materials with excellent comprehensive properties. Material extrusion (ME) is one such 3DP technique with extensive range of commercial applications especially in aerospace applications. Herein, the current research focusses on developing ME‐based filaments with excellent functional characteristics by using polylactic acid (PLA) as the base polymer. The hybrid combination of carbon nanotubes and zinc oxide is synthesized by constructing a core–shell nanoparticles (CNS) which is then added into PLA under different wt%. The characterization techniques, such as X‐ray diffraction, Fourier‐transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, etc., confirm the formation of CNS, which affirms to be an ideal reinforcement within PLA matrix. The mechanical properties of PLA are significantly enhanced with the tensile strength augmentation by 48.5% with only 0.2 wt% addition of CNS, while the thermogravimetric analysis results confirm the thermal stability enhancement for PLA/CNS composites. The fabricated PLA/CNS filaments display excellent flow characteristics as vindicated in rheological studies and ME‐printed prototypes exhibit refined output with exemplary finishing. The developed composite filaments can be harnessed as an advanced material in biomedical applications with exceptional properties. [ABSTRACT FROM AUTHOR]

Polyelectrolyte membrane (PEM) with improved proton conductivity and low methanol crossover are highly desirable for direct methanol fuel cells (DMFCs). Herein, the prime goal is to fabricate a ternary hybrid nanocomposite PEM by incorporating low-cost silane functionalized silica nanoparticles (AMPS) nanoparticles into the mixture of Nafion and PVDF-co-HFP, followed by sulfonation with chlorosulfonic acid which has not been reported by any earlier studies. Various physicochemical characterizations including FTIR, TGA, XRD, FESEM-EDS have been performed for the confirmation of formed sulfonated PVDF-co-HFP-AMPS-Nafion (SPAN) membranes. The initial studies including water/methanol uptake, swelling ratios, contact angle and improved ion exchange capacity (0.65 meq. g−1) confirms the hydrophilic and ion exchange properties of the SPAN membranes. The combination of highly hydrophobic partially fluorinated polymer along with hydrophilic AMPS and sulfonic acid moieties have resulted in significant improvement in proton conductivities (1.0 × 10–1 S.cm−1) and optimum methanol permeability values (8.79 × 10–7 cm2s−1) thereby exhibiting a better membrane selectivity value of 1.18 × 105 S.scm−3. Therefore, these unique SPAN membranes have the potentiality to be employed in methanol fuel cells. [ABSTRACT FROM AUTHOR]

The nanocomposite membranes consisting of polyvinylidene fluoride (PVDF) and graphene oxide (GO) are prepared via solution casting method and the membranes are subsequently sulfonated by chlorosulfonic acid. A series of physicochemical properties such as, thermogravimetric analysis (TGA), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) are carried out to investigate the thermal and structural properties of the prepared sulfonated PVDF GO (SPG) nanocomposite membranes. The preliminary studies including ion exchange capacity (IEC), water and methanol absorption are conducted for evaluating the feasibility of the SPG membranes to perform as a proton exchange membrane (PEM). The results are quite encouraging and acceptable for further investigations on membrane performance evaluation. The proton conductivity of the membrane has been remarkably improved after the sulfonation and found to be 0.075 S cm−1 at 25 °C which can be ascribed to the hydrophilic nature of incorporated graphene oxide nanoparticles as well as sulfonic groups attached to the PVDF chains which forms a suitable proton conduction channel and favors easy proton migration. Further, the blocking effect of GO provides an advantage for the methanol permeation rate thereby creating a torturous path and giving the methanol permeability value as 1.62 × 10–6 cm2s−1 which is 76.62% less than Nafion 117 membrane. Finally, the higher selectivity of the SPG membranes makes them more competitive than Nafion 117 membranes to employ as a PEM for DMFC. [ABSTRACT FROM AUTHOR]

In this review, we survey the state of the art on polymeric foams incorporating nano-scale fillers. Particular focus of the review is on foams from polyolefinic nanocomposite formulations incorporating a wide variety of fillers. The nano-scale additives can influence the foam structure and properties in two ways: Firstly, they can act as composite reinforcement to enhance the mechanical properties and functionality of the matrix polymer; and secondly, they can act as foaming-processing aids through modification of the rheological, thermal and crystallization properties of the matrix as well as serving as heterogeneous nucleation sites. Through a combination of these influences, and using advanced processing techniques it is possible to achieve nanocomposite foams that have higher cell density, and more uniform cell size or controlled cell-size distribution. Such controlled foam morphologies, in turn, can yield better specific mechanical properties resulting in more effective light-weighting solutions. Further, the nano-scale additives can impart additional desired functionality resulting in multi-functional foams. In this article, we provide an overview of the mechanical, thermal and a few other relevant functional properties – such as piezoelectric sensitivity, acoustics, and filtration efficiency – of foams prepared using nanocomposite formulations, along with the processing considerations for achieving high quality foams using such materials. [ABSTRACT FROM AUTHOR]

Proton conducting hydrophilic channels were created successfully in poly (ether ether ketone) (PEEK) by means of step by step modification followed by the optimization of sulfonation process (SPEEK70, DS=68.57%). Although highly sulfonated PEEK has excellent proton conductivity, it lacks in mechanical stability due to low swelling degree. Therefore, a potential method has been proposed in this work by integrating poly (sulfone) and nanosilica (SiO2) into SPEEK matrix. SPEEK 70 (S) was utilized to prepare blended nanocomposite membranes for further enhancement of hydrophilic channels. The blended nanocomposite membranes are, SPEEK/SiO2 as SNS, SPEEK blended with poly (sulfone) as SP, SPEEK blended with sulfonated poly (sulfone) as SSP and SPEEK blended with sulfonated poly (sulfone)/(SiO2) as SSPNS. All the prepared membranes were characterized and its performance was discussed in detail to identify the appropriate membrane for the better replacement of Nafion. Expected intermolecular interaction and its obstruction of free hydrophilic channels were confirmed with the gradual increase in proton conductivity from 0.0165 to 0.2557mS/cm. [ABSTRACT FROM AUTHOR]

The effect of Closite C93A nanoclay on the mechanical, thermal properties of diglycidyl ether bisphenol A (DGEBA) epoxy resin and epoxidized soybean oil (ESO) bioepoxy blend at various wt.% (10, 20, 30) cured with anhydride hardener (MHHPA) existence of 2-methylimidazole (2-MI) as an accelerator was investigated. The DGEBA/ESO blend systems optimized through the mechanical properties. The 20 wt.% DGEBA/ESO blend systems exhibited higher tensile and impact strength incorporation of 0.5–2.5 wt.% C93A nanoclay. The curing reaction of DGEBA blends and its nanocomposites with MHHPA, 2-MI was explored by non-isothermal differential scanning calorimetry (DSC). The thermal stability of DGEBA/20%ESO blend enhanced by loading of 2.5 wt.% C93A nanoclay which restrict the flexibility of chain and obstructed the decomposition process. The formation of exfoliated inside the clays in the DGEBA/ESO/2.5%C93A nanocomposites corroborated by X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis. [ABSTRACT FROM AUTHOR]

The effect of incorporation of silver nanoparticles (SNPs) in an organic–inorganic metal nanocomposite was investigated. A renewable resource‐based polyurethane (PU) was synthesized by an in situ polymerization method with a polyol: diisocyanate ratio of 1:1.2, an epoxy (glycidol) terminated polyurethane (PE) was prepared by a polyol: diisocyanate: glycidol ratio of 1:3:3, a hydroxy terminated poly (dimethyl siloxane) (HTPDMS) modified PE (PES) was synthesized by the incorporation of 10 wt.% of HTPDMS into the PE and a silver nanocomposite (SNC) was synthesized by the addition of 0.3 wt. % SNPs into the PES matrix. Fourier transform infrared spectroscopy analysis confirmed the existence of NHCOO, Si‐O‐Si and oxirane linkages. The structural analysis was carried by X‐ray diffraction analysis in order to verify the face centered cubic structure of SNPs. The differential scanning Calorimetry analysis and thermogravimetric analysis showed the improved thermal stability by the addition of thermally stable epoxy linkages, high energy siloxane linkages and SNPs. Thus an advanced composite material with desirable properties for industrial applications have been prepared in the current work. POLYM. COMPOS., 39:E2390–E2396, 2018. © 2017 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Abstract: Biobased polymer has taken tremendous attention in recent times. In the present study bio‐based polyurethane have been synthesized from the vegetable oil i.e., dehydrated castor oil, 1,4‐butanediol and isophorone diisocyanate in presence of a catalyst by solution polymerization method. Then polyurethane nanocomposites were synthesized using different amount of nanoclay (C30B) (1, 3 and 5 wt%). The synthesis of polyurethane and its nanocomposites were confirmed by FTIR and XRD analysis. The mechanical properties such as tensile strength (2.2–4.5 MPa), elongation at break (299%–435%) hardness (46–70) and abrasion resistance (351–201 mg/1,000 cycles) increased with the increase of nanoclay content. The initial thermal degradation temperature found to increase from (220 to 290°C) with the increase of nanoclay content in the nanocomposites. The nanoclay was interacted with the hard segment of the matrix polymer as reflected from the atomic force microscopy studies. Weathering study revealed that nanocomposites have higher weather resistance capacity than pristine polyurethane. It can be concluded that the prepared nanocomposites might be good outdoor topcoat materials. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide (rGO) was synthesized from graphite flakes utilizing improved Hummers method via graphene oxide (GO) precursor. The oxidation of graphite and subsequent reduction of GO were confirmed by using FTIR, XRD, Raman spectroscopy and TEM techniques. The nanocomposite adhesives were developed using GO and rGO with different loading of 0–1.0 wt%. The adhesive strength was studied by conducting lap shear test and it was noticed that, Ep-0.5 GO adhesive exhibited the highest strength among all adhesive formulations and showed ∼50% increment than pristine epoxy. Impact strength evidenced noticeable enhancement with decrease in notch depth from 2.54 to 0.5 mm for all adhesive systems clearly indicating brittle to ductile transition due to the declining stress concentration area. The fracture analysis of impact samples and extent of fillers dispersion were visualized by SEM. SEM micrographs evidenced clear surface contrast of samples based on variable notch depth. The electrical resistivity in Ep-rGO systems showed 93% decrease with 1 wt% rGO loading, while thermal conductivity of Ep-0.5 GO revealed 211% increment as compared to pristine epoxy. [ABSTRACT FROM AUTHOR]

Waterborne polyurethane coatings made from castor oil as polyol resource, replacing oil from fossil fuels are attracting lot of recognition during recent decades. In this review, castor oil and its modifications to synthesize various biobased waterborne polyurethane and their nanocomposite systems have been addressed. Various synthesis procedures for waterborne polyurethane dispersions and their applications as a coating material have been described. This review will be helpful to the green research community for selection of monomer and further development of biobased waterborne polyurethane utilizing advanced technology. [ABSTRACT FROM PUBLISHER]

The present study represents the synthesis of flexible polyurethane nanocomposite foam using Cloisite 30B nanoclays varying at 1, 2, and 3 wt%. The polyurethane nanocomposite foam formulated with 50:50 weight ratio of synthetic polyether polyol and renewable resource-based castor oil. The progress of isocyanate reaction and formation of bidentate urea through H-bonding in the polymeric matrix phase were confirmed from Fourier transform infrared analysis. The surface morphology of the nanocomposite foams was examined by scanning electron microscopy and X-ray diffraction analysis. Polyurethane nanocomposite foam displayed exfoliated structures at 3 wt% Cloisite 30B. The thermal and mechanical properties were also studied to report the impact of Cloisite 30B in biobased flexible polyurethane foam. Enhanced thermogravimetric outcome signified higher thermal stability of polyurethane nanocomposite foam as compared to polyurethane foam. Further, improvement of the soft segment glass transition temperature (Tg) confirmed the role of Cloisite 30B in the phase separation behavior between the hard segment and soft segment in nanocomposite foams. A significant enhancement in the mechanical strength with incorporation of a small amount of Cloisite 30B nanoclay to the flexible polyurethane foam allows it for various low cost applications. [ABSTRACT FROM AUTHOR]

Biobased polyurethane nanocomposite (PUNC) adhesive containing 3 wt% of organically modified montmorillonite (OMMT) nanoclay was prepared; wherein the reference material consisting of partially biobased aliphatic isocyanate derived from palm oil and soft segment derived from castor oil (CO) as well as transesterified castor oil (TECO). The TECO was confirmed using proton nuclear magnetic resonance (1HNMR) study. Further, the corresponding molecular weight (Mw) of CO and TECO was determined using GPC analysis. Afterwards, the formation of the chemical shift values of chemical functions such as ester, urethane linkages were detected by I3C-NMR spectroscopy. A non isothermal analysis of PUNC was studied using differential scanning calorimetry (DSC) at three different heating rates of 5, 7.5 and 10°C/min. The curing kinetics parameters such as activation energy () and least square values were calculated by employing Ozawa model which indicated the molecular mobility of the system under curing in the presence of montmorillonite. The result depicted that the Ozawa model was suitable to calculate the progression of conversion in PUNC adhesive with good accuracy. Further, the thermal stability of the unfilled PU and PUNC adhesive was studied by thermo gravimetric analysis (TGA) and corresponding decomposition energy values were determined using Coats and Redfern method. [ABSTRACT FROM AUTHOR]

The current research focuses on the degradation kinetics of fully bio-based hybrid bionanocomposites of poly(lactic acid) (PLA), utilizing banana fiber and nanoclay as reinforcing fillers. The bionanocomposites were prepared using melt blending technique followed by injection molding. The reinforcing effect of silane treated banana fiber (SiB) and Closite 30B (C30B) nanoclay on the thermal stability and fire retardancy of PLA has been studied. Isoconversional kinetic analysis using Friedman and Flynn-Wall-Ozawa method as well as analysis based on parameters at the maximum degradation rate (Kissinger method) were employed to understand the thermal degradation kinetics in the bionanocomposites. The results from thermogravimetric analysis (TGA) revealed that bionanocomposites have improved thermal stability. The UL-94 horizontal burning test and cone calorimetry have been used to screen the flammability performance of PLA and its biocomposites as well as bionanocomposites. The results revealed that the incorporation of SiB and C30B nanoclay improved fire retardancy. Further, the structural characterization has been carried out using FTIR. [ABSTRACT FROM AUTHOR]

The current study aims to investigate the influence of UV aging on the properties of green polyurethane (MBPU) and polyurethane/nanosilica composite (MBPU/NS) coatings synthesized from transesterified castor oil and palm oil isocyanate for an exposure period of 1250 h. Changes in the mechanical properties, structural features, morphological and coating properties have been monitored at every 250 h by scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and colorimetry etc. MBPU/NS with 2.5 wt% of NS has been considered to be the optimum composition for a comparative UV aging analysis against neat MBPU. FTIR and XPS analysis revealed changes in chemical structure of MBPU and MBPU/NS-2.5 composite with reduction in -NHCO, C-C, C=O group concentrations. SEM and AFM micrographs indicated increase in roughness parameter with appearance of blisters and cracks on the exposed surface. Mechanical test results showed that UV aging decreases the tensile strength and elongation at break due to chain scission. The yellowness index (ΔYI) follows a systematic increasing trend with increment in irradiation time which indicates photodegradation of polyurethane. However, MBPU/NS-2.5 exhibited lower photo-oxidative degradation which can be due to its high UV absorption ability. Graphical Abstract: [ABSTRACT FROM AUTHOR]

The current study details on the moisture absorption behavior and its effect on the hybrid bionanocomposites of polylactic acid (PLA). In order to improve the compatibility between PLA and fiber, silanization was performed on fiber as well as C30B nanoclay was used as the secondary reinforcing filler. Silanization was confirmed through Fourier transform infrared study. In addition, thermogravimetric analysis (TGA) of fiber proved that hydrophilicity of fiber could decrease after silane treatment. Bionanocomposites of PLA were prepared using melt blending technique followed by injection molding. Samples were immersed in distilled water for 30 days at room temperature to analyze the moisture absorption behavior and its kinetic parameter. The results from moisture study revealed that PLA/fiber/nanoclay bionanocomposites have higher moisture resistance than PLA/fiber biocomposites. Further, the changes in mechanical as well as thermal properties of PLA and its composites during moisture absorption have been carried out. With increase in percentage of moisture absorption, the mechanical strength and modulus of composites decreased significantly, however, the unnotched impact strength and elongation at break found to improve. TGA of PLA and its composites revealed that thermal stability of composites decreased after moisture absorption. The morphology of the composites was monitored during moisture absorption, and the result revealed that moisture absorption has severely damaged the matrix–fiber interface. [ABSTRACT FROM AUTHOR]

This research was accomplished to examine the mechanical, morphological and crystallization kinetics study of polyethylene/silver nanoparticles (Ag-NPs) nanocomposite films. In this research, low-density polyethylene (LDPE) nanocomposite films were prepared containing Ag-NPs using maleic-anhydride-grafted low-density polyethylene (LDPE-g-MAH) as a compatibilizer by the melt mixing process. From mechanical property evaluation, it is revealed that the LDPE/LDPE-g-MAH/Ag-NPs nanocomposite films showed decreased tensile strength as compared with virgin LDPE matrix. Thermal characteristics of the prepared virgin LDPE and its nanocomposite films were studied by differential scanning calorimetry (DSC). Comprehensive analysis of different kinetic models such as the Avrami and Mo model on non-isothermal crystallization kinetics was performed in order to correlate the rate of crystallization and its various kinetic parameters. Further, the macrokinetic equation as proposed by Malkin has been applied to describe the kinetics of crystallization in the light of the Avrami equation. Concerning virgin LDPE and Ag-NP-reinforced LDPE, the former shows primary crystallization, whereas the later exhibits both primary and secondary crystallization with varying Avrami exponents. Kinetic parameters are recognized, and confirm the influence of Ag-NPs on crystallization kinetics. X-ray diffraction spectroscopy and transmission electron microscopic analysis of the nanocomposite films were conducted to verify the dispersion of inorganic filler particles in the resulting hybrids. [ABSTRACT FROM AUTHOR]

Waterborne polyurethane dispersions (WPUDs) were synthesized successfully from castor oil-based polyol, isophorone diisocyanate and dimethylol propionic acid with NCO/OH ratio of 1.5. Different weight percentages of cloisite 30B (1, 2, and 3 wt%) were loaded with WPUDs to prepare nanocomposite films. Prepared prepolymer and nanocomposite films were characterized using FTIR, XRD, SEM, TEM, DSC, and TGA techniques, and coating properties, such as pencil hardness, abrasion resistance, impact resistance, and contact angle, were evaluated. The results obtained from different amounts of clay loading were compared with the pristine castor oil-based WPUDs. The FTIR spectra deconvolution technique was used to study the hydrogen bonding effect within the polymer with an increase in clay content. TGA analysis showed that the thermal stability of WPUDs increases with cloisite 30B (C30B) content. The surface morphology and hydrophilicity/hydrophobicity nature of the nanocomposite films were characterized using scanning electron microscopy and contact angle measurement. The results obtained from tensile tests indicated that the mechanical property of the dispersion system improved with C30B content. A high-performance castor oil-based nanocomposite coating with low volatile organic component can be targeted as an outcome of this work. [ABSTRACT FROM AUTHOR]

Titanium dioxide nanofiber (TNF) was synthesized from the anatase phase of titanium dioxide by the hydrothermal process. The synthesized TNF was reinforced with poly(trimethylene terephthalate)/poly(butylene adipate- co-terephthalate) blend to enhance the compatibility and improve the mechanical properties of the blend. The nanocomposite blends were prepared by using a twin-screw extrusion process with different percentages (2.5%, 5.0%, 7.5%, and 10%) of TNF. The synthesized TNF phase structure was investigated by X-ray diffraction, scanning electron microscopy, and Fourier-transform infrared characterization. Enhanced compatibility was observed between the nanofiber and the polymer matrix, which was further confirmed by X-ray diffraction and scanning electron microscopy analysis. The synthesized nanocomposites exhibited higher thermal stability and enhanced mechanical properties compared with the neat poly(trimethylene terephthalate)/poly(butylene adipate- co-terephthalate) matrix. J. VINYL ADDIT. TECHNOL., 22:529-538, 2016. © 2015 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Non-isothermal crystallization kinetics of virgin polypropylene (PP) and its nanocomposites have been evaluated using differential scanning calorimetric technique. The nanocomposites were prepared using melt intercalation method. It is observed that the crystallization peak temperature of nanocomposite is marginally higher than virgin PP at various cooling rates. The non-isothermal crystallization melt data were analysed using Avrami, Ozawa and Mos models. The half-time for crystallization decreased with incorporation of clay nanoparticles. The values of crystallization rate constant and cooling rate at unit crystallization time showed that the crystallization rate increased with the increasing of cooling rates for virgin PP and nanocomposite, but the crystallization rate of nanocomposite was faster than that of PP at a given cooling rate. The activation energy for non-isothermal crystallization of virgin polymer and nanocomposites based on Kissinger method has been determined to be 186 and 196 kJ mol−1, respectively. The polarized micrographs showed that the number of effective nuclei increased in the PP-clay nanocomposite, where the clay acts as a heterogeneous nucleating agent during the crystallization of the nanocomposite. [ABSTRACT FROM AUTHOR]

Unsaturated polyester (UP)-toughened epoxy nanocomposites were prepared, and their effective mechanical and thermal properties were studied. Two types of organo-modified montmorillonite (OMMT) clays were used to prepare the nanocomposites. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis showed the formation of exfoliated silicate layers in the UP-toughened epoxy matrix. Mechanical tests revealed that nanocomposites (containing 1 wt% OMMT clay) showed an increase in tensile strength to 13.8%, flexural strength to 10%, and impact strength to 4% compared with an UP-toughened epoxy blend. The effect of different heating rates on the curing behavior of UP-toughened epoxy nanocomposites was investigated using non-isothermal differential scanning calorimetry. The data were interpreted using the Kissinger and Flynn–Wall–Ozawa models to find the curing reaction parameter. The water uptake behavior for nanocomposites increased with the addition of OMMTs. Scanning electron microscopy micrographs indicated morphological changes in the impact fractured samples of UP-toughened epoxy nanocomposites. [ABSTRACT FROM AUTHOR]

In the present investigation, recycled polypropylene (rPP) used as a matrix was modified by incorporating nanofillers through melt blending technique to prepare a masterbatch of nanocomposites. Untreated sisal fibre and mercerised sisal fibres were further incorporated into the nanocomposites for the preparation of bionanocomposites. Bionanocomposites containing 40 wt% of UT fibre and 5 wt% of MA-g-PP revealed an increase in the tensile strength and modulus to the tune of 27% and 370%, respectively, compared to rPP. The flexural strength and modulus also increased to the tune of 129% and 269%, respectively, compared to rPP. Further, the surface treatment of the fibre slightly increased the mechanical properties and stiffness of bionanocomposites. Interfacial strength between fibre and matrix was also evaluated by using Turcsanyi and Sato–Furukawa models. Damage tolerance of rPP nanocomposites and its bionanocomposites was evaluated using single-edge-notch specimens. The notch length ‘a’ to width ‘W’ ratios,a/W, were chosen as 0.3, 0.45 and 0.6. The nanocomposites showed better damage tolerance as compared to the rPP matrix. The corrugated structure with increased fractured surface area was observed in scanning electron microscopy. Better dispersion of clay in the nanocomposites was observed in transmission electron microscopy. [ABSTRACT FROM PUBLISHER]

This study examined the dynamic mechanical properties of sisal fiber reinforced unsaturated polyester (UP) toughened epoxy nanocomposites. The chemical structures changes in Epoxy, UP and UP toughened epoxy (Epoxy/UP) systems were characterized by Proton Nuclear magnetic resonance (1HNMR) spectroscopy. The morphological alterations of the nanocomposites were analyzed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The untreated, chemically treated fibers, nanoclays, and the fiber reinforced Epoxy/UP nanocomposites were confirmed by FTIR spectrometer. The obtained mechanical results showed that alkali-silane treated fibers improve the tensile strength (96%) and flexural strength (60%) of the Epoxy/UP nanocomposite than that of Epoxy/UP blend due to the strong interfacial bonding between the sisal fiber and matrix. The fracture toughness ( KIC) and fracture energy ( GIC) of treated sisal fiber reinforced DGEBA/UP/C30B nanocomposites found to be higher than that of untreated sisal fiber nanocomposites. The dynamic mechanical analysis (DMA) reveals that the fiber reinforced Epoxy/UP nanocomposites contains 30 wt% treated fiber and 1 wt% nanoclays, exhibits the highest storage modulus and better glass transition temperature ( Tg) among the other kind of systems. The surface morphology of the fibers, fractured surface of the resins and composites were confirmed by scanning electron microscope (SEM). POLYM. COMPOS., 37:2832-2846, 2016. © 2015 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

This work reports on the influence of moisture absorption and accelerated weathering on the properties of graft copolymer compatibilized bionanocomposites of poly(lactic acid) (PLA). Moisture absorption tests were conducted for 30 days by immersing the samples in a distilled water bath at room temperature, and the amount of moisture absorbed in each time interval was measured. The rate of moisture uptake decreased by incorporation of C30B nanoclay and graft copolymer into fiber-reinforced PLA composites. Changes in the mechanical properties of composites in each time interval of moisture absorption were investigated using tensile and impact tests. Exposure to moisture caused significant drops in the mechanical properties. The morphological characterization of biocomposites during the aforementioned tests has been made using SEM, while bionanocomposites were analyzed by TEM. Further, this paper also reported the effect of accelerated weathering on the mechanical properties and the results are confirmed through SEM analysis. Biodegradation behaviors of PLA biocomposites and bionanocomposites have also been studied. [ABSTRACT FROM AUTHOR]

The nanocomposites were prepared using melt intercalation method and the effects of the processing conditions on silver nanoparticles dispersion were investigated by transmission electron microscopy. Non-isothermal crystallization kinetics of virgin polypropylene (PP) and its nanocomposites have been evaluated using differential scanning calorimetric technique. The non-isothermal crystallization melt data were analyzed using macro kinetics equation with the help of Avrami, Malkin, and Mo's models. The crystallization rate increased with the increasing of cooling rates for virgin PP and nanocomposite, but the crystallization of nanocomposite was faster than that of PP at a given cooling rate. The activation energy for non-isothermal crystallization of virgin polymer and nanocomposites based on Kissinger method has been determined to be 186 and 211 kJ/mol, respectively. Transmission electron microscopy analysis reveals balanced dispersion and presence of some silver nanoparticles aggregates, which act as a heterogeneous nucleating agent during the crystallization of the nanocomposite. [ABSTRACT FROM AUTHOR]

Poly(ethylene glycol) (PEG) was mixed at various weight percentage with biodegradable poly(lactic acid) (PLA) via direct melt compounding method. Nanocomposites of PLA/PEG, with two types of organoclay namely, cloisite 93A (C93A) and cloisite 30B (C30B) were also prepared by melt blending method. The crystallization behaviors of PLA/PEG and PLA/PEG/organoclay were studied using differential scanning calorimetry (DSC). The isothermal crystallization kinetics has been investigated using the Avrami’s equation. In PLA/PEG, the PLA crystallized first followed by crystallization of PEG during the cooling. The viscoelastic behavior of the PLA/PEG and PLA/PEG/organoclay were investigated by dynamic mechanical analysis where the nanocomposites showed higher magnitude of storage modulus. The plasticizing effect of PEG acts predominantly in the mechanical performance of PLA/PEG, which shows increased percentage elongation and impact strength in the blend. The sample with 20 wt% PEG showed optimum impact strength. Again, the nanocomposite with 3 wt% C30B exhibited better tensile strength and modulus than the sample with C93A. The characterization of fractured surface of the matrix polymer and the blend were compared through scanning electron microscopy. The rheological and compostability study of the system were further investigated. [ABSTRACT FROM AUTHOR]

The present study highlights the structure and property relationships of epoxidized castor oil (ECO) toughened Diglycidyl Ether of Bisphenol A (DGEBA) epoxy nanocomposites. Toughened epoxy systems have been prepared by an addition of 10-40wt% ECO to the DGEBA epoxy resin. Nanocomposites were prepared by mixing small amounts of Cloisite 30B (C30B) clay and 3-aminopropyltriethoxysilane to the DGEBA/ECO blends. The chemical structure of toughened systems was confirmed using proton nuclear magnetic resonance and fourier transform infrared spectroscopy. The triethylenetetraamine-cured DGEBA/ECO/C30B (8:2:0.1) nanocomposites exhibited tensile strength (50 MPa), tensile modulus (1.7 GPa), flexural strength (120 MPa), flexural modulus (3.02 GPa), and elongation (19%). The fracture toughness (critical intensity factor, KIC) and fracture energy (critical energy release rate, GIC) of DGEBA/ECO/C30B (8:2:0.1) system found to be higher than the other systems (2.5 MPa.m½ and 1.8 kJ/m2 for KIC and GIC, respectively). The thermal stability and heat of reaction of DGEBA/ECO blends increase with the addition of C30B clays that were analyzed using thermogravimetric analysis and differential scanning calorimetry. Rheological characterizations of uncured samples revealed a pronounced effect of the C30B clay on the DGEBA/ECO blend systems that exhibited a shear-thickening behavior. On the other hand, the dynamic mechanical properties also revealed that the addition of C30B clays to the DGEBA/ECO blend a significant enhancements in viscoelastic and cross linking density behavior. Scanning electron microscope analysis was used to study the fractured morphology of DGEBA, DGEBA/ECO, and its nanocomposite systems. [ABSTRACT FROM AUTHOR]

Castor oil-based epoxy monomer was prepared using a two-step approach: epoxidation of castor oil, followed by acrylation of epoxidized castor oil. A bio-based diglycidyl ether of bisphenol A (DGEBA) epoxy nanocomposites was prepared by the incorporation of organo-modified montmorillonite (OMMT) clay to the DGEBA/AECO system. The cured bio-based DGEBA epoxy nanocomposites at 0.80:0.2:0.001 g/g exhibited higher tensile strength (56 MPa), tensile modulus (1933 MPa), flexural strength (132 MPa), flexural modulus (2518 MPa), elongation (23.1 %), and impact strength (34 kJ/m2). The nanocomposites at 0.6:0.4:0.001 g/g can easily bend up to 360° without any damage; similarly, the 0.8:0.2:0.001 g/g system can bend up to 180°. Thermal behaviour of the bio-based epoxy systems was characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA). The obtained nanocomposites displayed a higher char yield (8.9 %) at 700 °C and glass transition temperature (108 °C) than the DGEBA/AECO systems. Further SEM analysis was used to study the morphological changes in the fractured surfaces of bio-based epoxy systems, which reveals that crack propagation decreases with addition of AECO to the DGEBA epoxy system. [ABSTRACT FROM AUTHOR]

A promising green biosensing material, nano-cerium oxide (CeO) decorated reduced graphene oxide (RGO) nanohybrid reinforced chitosan (CS) nanocomposite has been synthesized as a transducer phase for the effective immobilization of glucose oxidase (GOx) enzyme. CeO nanoparticles were grown on the RGO nanosheet by facile hydrothermal treatment. The effective growth of synthesized nano-CeO on the RGO was evident from X-ray diffraction, scanning electron microscopy and transmission electron microscopy and Raman analysis. Morphological studies confirmed the effective immobilization of GOx on the chitosan nanocomposites modified FTO electrode. The electrocatalytic response of the GOx/nano-CeO-RGO/CS/FTO bioelectrode was investigated using electrochemical impedance and cyclic voltammetry studies. The obtained results indicate that as compared with bare CeO nanoparticles and RGO, the nano-CeO/RGO nanohybrid shows significant electrochemical activity and provides an adequate microenvironment for effective enzyme immobilization due to the excellent synergism between the CeO nanoparticles and RGO nanosheet. Graphical Abstract: Scheme 1: Schematic diagram of graphene nanohybrid reinforced Chitosan nanocomposite modified biosensing matrix.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

In the current study, nano-clay was incorporated in toughened epoxy modified with epoxidized soybean oil (ESO) to improve the mechanical and thermal properties. Curing behavior was studied by Fourier Transform Infrared spectroscopy and Differential Scanning Calorimetry analysis to investigate the effect of ESO bioresin and nanoclay on cross-linking reaction. The increase in enthalpy of curing reaction and decrease in peak temperature of nanocomposite corroborated the catalytic effect of clay on the curing process. The thermal stability parameters like integral procedural decomposition temperature and decomposed activation energy were determined using Horowitz and Metzger equation. Dynamic mechanical analysis demonstrated the high storage modulus, improved crosslink density and good damping behavior of nanocomposite. Thermo mechanical analyzer was used to examine the coefficient of thermal expansion (CTE) of bio-based epoxy blend and nanocomposite in both glassy and rubbery region. The CTE value is decreased after addition of clay to the modified epoxy blend which confirmed the improved dimensional stability of the nanocomposite. TEM and X-ray diffraction analysis confirmed both intercalated and exfoliated clay platelet within the epoxy blend. [ABSTRACT FROM AUTHOR]

In this study, the bio-based epoxy nanocomposites were prepared from acrylated epoxidized castor oil toughened diglycidyl ether of bisphenol A epoxy network filled with sisal fibers and cloisite 30B clay. The chemical structure of acrylated epoxidized castor oil resin was confirmed by Fourier transform infrared and Proton nuclear magnetic resonance (1HNMR) spectroscope techniques. Mechanical and thermal properties of the sisal fiber reinforced acrylated epoxidized castor oil toughened diglycidyl ether of bisphenol A epoxy composites and nanocomposites were investigated. Mechanical tests revealed that bio-based epoxy nanocomposites (containing 80% diglycidyl ether of bisphenol A/20% acrylated epoxidized castor oil / 30% treated sisal fiber/ 1% cloisite 30B weight ratio) were found to be higher in tensile strentgh to 78%, flexural strentgh to 44% and impact strength to 20% than the 80% diglycidyl ether of bisphenol A/20% acrylated epoxidized castor oil matrix. Thermogravimetric analysis results showed that the thermal stability of diglycidyl ether of bisphenol A /acrylated epoxidized castor oil matrix increased with the incorporation of alkali-silane-treated sisal fiber and cloisite 30B nanoclay. The apparent activation energy was increased from 236 to 273 KJ/mol with the addition of 1% cloisite 30B clay and 30% alkali-silane-treated sisal fiber to the 80% diglycidyl ether of bisphenol A /20% acrylated epoxidized castor oil matrix. Scanning electron microscopy was performed to investigate the fracture behaviour at the fiber-matrix interface. [ABSTRACT FROM AUTHOR]

Shape-memory polyurethane (SMPU) having segmented structure, with 4,4-diphenylmethane diisocyanate as hard segment, poly caprolactone diol 4000 as soft segment, and 1,4-butane diol as chain extender was synthesized using two-step polymerization technique. This pure SMPU was blended with unmodified and modified multiwalled nanotubes (MWNTs), using twin screw extruder and melt spinning technique. X-Ray diffraction, differential scanning calorimetry, morphological analysis, and shape-memory behavior results for the SMPUs are presented in this study. An improvement in the thermal stability and degradation temperature of the SMPU was observed especially in the soft segments, upon 0.1% loading of MWNT. Slight decrease in crystallinity was recorded for MWNT/SMPU as compared to virgin SMPU. The recovery ratio of SMPU fiber increased to 90% with 0.1 wt% loading of MWNT, but the spinnability decreased due to reduced crystallinity and viscosity with an addition of nanotubes to the polyurethane matrix. [ABSTRACT FROM AUTHOR]

ABSTRACT A candid approach to thermal dehydroxylation was used for the modification of clay, to achieve improved thermal stability of a polymer nanocomposite. The modification of clay using alkyl ammonium salt has been found disadvantageous due to various aspects; hence the approach to dehydroxylation was an innovative step to overcome the difficulties in achieving a thermally stable polymer clay nanocomposite. Therefore, a detailed study of thermal stability of polymer clay nanocomposites has been carried out using isoconversional TGA methods of Flynn-Wall-Ozawa and Kissinger. Also, the reaction model involved in the decomposition process of polypropylene (PP) and its nanocomposites have been investigated. From the thermal kinetic analysis, it was clear that the thermal dehydroxylation method can be used as an effective approach for clay modification and the use of organic alkyl ammonium salt can be avoided. Furthermore, to predict the flame-retardant effectiveness of the thermally dehydroxylated clay, the cone calorimeter analysis was carried out. A comparison of the flame-retardant effectiveness of the organophillic clay and thermally dehydroxylated clay was presented. [ABSTRACT FROM AUTHOR]

Renewable resource-based epoxidized castor oil (ECO) was synthesized and used as a prime material to develop acrylated epoxidized castor oil (AECO) networks. AECO nanocomposites were prepared by the sol-gel method from organo-modified montmorillonite (OMMT) clay and silane. It was found that the AECO/1 wt.% OMMT system increased in tensile strength from 28 to 37 MPa and flexural strength from 54 to 63 MPa as compared with the AECO system. The non-isothermal cure kinetics of the bio-based systems was studied using differential scanning calorimetry. The activation energy of the AECO/OMMT system obtained from Kissinger and Flynn-Wall-Ozawa models is lower than that of AECO system. [ABSTRACT FROM AUTHOR]

A candid approach to analyze the performance characteristics of phenyl phosphonate-functionalized zirconium oxide and pure zirconium oxide (ZrO) fillers reinforced chitosan nanocomposites and their suitability as a potential biomaterial for the development of transducer surface in biosensing device has been investigated in this communication. Functionalization of ZrO has been carried out using sulfophenylphosphonate which was confirmed using Fourier transform infrared spectrographs. The electrostatic intercalation of chitosan with filler particles was monitored using electrochemical impedance analyzer which exhibits lowest bulk resistance which is highly effective for ionic switching. Incorporation of zirconium sulfophenylphosphonate (ZrSP) the ionic conductivity of the chitosan film attained a value of 1.2 × 10 S/cm as compared to the unmodified one which is a prefeasibility work for the fabrication of biosensing platform. Variation in performance characteristics has been evaluated through morphological and thermal characterization. TGA and DSC analysis reveal that the thermal stability and decomposition temperature of the nanocomposites were improved by the addition of reinforcing filler particles. XRD and SEM and TEM results support the above assumption. The continuous alignment of the proton transfer channels of the nanocomposites was thoroughly investigated by AFM analysis which revealed phase morphology for improved enzyme entrapment. Further, surface functionalized nanofillers result considerable increment of mechanical properties in terms of elastic modulus and tensile stress. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

This work is focused on the modification of montmorillonite by hexadecyl trimethyl ammonium bromide (HDTMA) as a surfactant by cation exchange reaction. HDTMA-modified layered silicate (HDTMA-MLS) was compounded with polylactide (PLA) by melt extrusion technique for making nanocomposites. These nanocomposites were subjected to morphological, rheological, thermal and mechanical analyses. Variations in mechanical properties, plasticity and thermal stability with the addition of modified nanoclays in PLA were investigated. The presence of HDTMA in clay minerals was confirmed by Fourier-transform infrared (FTIR) analysis that shows two absorption bands at 2927 cm−1 and 2860 cm−1 that corresponds to the asymmetric and symmetric stretching vibrations of C–CH2 of alkyl chain, respectively, and the band at about 1470 cm−1 was assigned to the vibration of trimethyl ammonium quaternary group C–N(CH3)3. Melt rheology of virgin PLA and nanocomposites performed by small amplitude oscillation shear measurement. Incorporation of HDTMA-MLS (1–7 wt%) into PLA matrix yields significant improvements in the elastic modulus (G′) of nanocomposites due to intercalation at high temperature. X-Ray diffraction (XRD) and transmission electron microscopy determined that PLA/HDTMA-MLS nanocomposites were intercalated. Nanocomposite prepared using 5 wt% HDTMA-MLS exhibited optimum mechanical performance with an increase in the tensile and flexural modulus and impact strength as compared to virgin PLA, which confirms intercalation morphology. Dynamic mechanical analysis study revealed an increase in the storage modulus (G′) confirming a strong interaction between the modified clays and PLA. Differential scanning calorimetry and thermogravimetric analysis showed improved thermal properties. Heat deflection temperature of the matrix also increases in the presence of nanoclays. [ABSTRACT FROM PUBLISHER]

Green nanocomposites of poly(lactic acid)/banana fibre/nanoclay were successfully prepared using melt-blending technique followed by injection moulding. Untreated and chemically modified banana fibres and organically modified nanoclay (Cloisite 30B) were used as reinforcing agent within the poly(lactic acid) matrix. The banana fibres were subjected to various chemical modifications such as mercerization, silane treatment, sodium lauryl sulphate treatment, permanganate treatment and combination of mercerization and silane treatment. The biocomposites and bionanocomposites were subjected to characterization tests i.e. mechanical properties, dynamic mechanical analysis, differential scanning calorimetry, thermogravimetric analysis, heat deflection temperature (HDT), morphological properties using scanning electron microscopy and transmission electron microscope and water-absorption studies to evaluate the effect of chemical modification of banana fibre and incorporation of nanoclay. Silane-treated fibre-reinforced poly(lactic acid) composites and its bionanocomposites displayed optimum tensile and flexural properties than that of virgin poly(lactic acid) resin, whereas the impact strength of composites showed a reverse order due to the brittle nature of matrix. Dynamic mechanical analysis result shows that the storage modulus of the bionanocomposites increases with respect to the virgin poly(lactic acid) and biocomposites. Differential scanning calorimetry results revealed that the glass transition was not significantly changed; however, the incorporation of both silane-treated fibre and C30B nanoclay enhanced the nucleation of poly(lactic acid) crystallites as well as increased the melting temperatures. The results of thermogravimetric analysis depicted that fibre modification and incorporation of nanoclay can improve the degradation temperature of the composites. Scanning electron micrographs demonstrated improper dispersion of untreated fibres and proper dispersion of treated fibres within the poly(lactic acid) matrix, thereby revealing the interfacial adhesion between the fibres and matrix. Additionally, the composites were subjected to water-absorption studies, which revealed that bionanocomposites exhibited better water resistance than biocomposites. [ABSTRACT FROM AUTHOR]

This research aims to study the effect of accelerated weathering conditions on the photodegradation characteristics for fibrillar silicate clay-filled Polypropylene (PP) nanocomposites in the presence of metallocene linear low density polyethylene (m-LLDPE). Silane-treated attapulgite (ATP) clay along with ethylene octene elastomer-grafted maleic anhydride (POE-g-MAH) was used to compatibilize both blend and nanocomposite system. The result showed that developed PP/m-LLDPE nanocomposites displayed good UV resistance with little change in retained stress-at-break and elongation-at-break values. Balanced loss of toughness values noted maintaining higher fracture toughness values for nanocomposites containing 5 phr ATP clay. Infrared analysis was used to detect progress of degradation followed by change in carbonyl index revealed predominated chain scission in late irradiation, while crosslinking was dominant for initial irradiation period. An increase in crystallinity during UV exposure (chemi-crystallization) was detected with exposure time for all compositions and virtually independent of initial structure of the polymer. The highest value of crystallization observed for PP and the lowest one for nanocomposites containing 5 phr of ATP clay revealed good oxidation stability. Surface morphology revealed induced degradation throughout cross-section of PP, while severity of the surface degradation was significantly reduced for developed nanocomposites. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

A candid approach to analyze the prospects of organic–inorganic nanocomposites as polyelectrolytes has been presented in this communication. Structurally modified aromatic sulfone polymer, polysulfone, was successfully prepared through modification with trimethyl silyl chlorosulfonate, which was confirmed from Fourier transform infrared spectrographs. Different classes of nanofillers like layered silicates and inorganic oxides were reinforced in the modified macromolecular system using solvent casting technique. A comparative study was performed to evaluate the effectiveness of filled polyelectrolyte membranes in a direct methanol fuel cell operated at 60°C with 1.0 M methanol feed. Atomic force micrographs revealed the phase morphology, responsible for this behaviour. The variation in ion transfer behavior as a function of structural modification and filler composition was also conducted. Furthermore, supportive information for these characterizations were derived from morphological (x-ray diffractometry), thermal (thermogravimetric analysis), and liquid uptake studies. [ABSTRACT FROM AUTHOR]

In this study, organically modified Na-MMT clay was used for the preparation of blend nanocomposites containing different ratios of polypropylene (PP) and ethylene propylene diene monomer (EPDM) elastomer in a twin screw extruder. Maleic-grafted PP (MAPP) was used as compatibilizer for making PP hydrophilic. Surface modification of Na-MMT was made by using amino propyl trimethoxy silane (APS) and trimethyl amine as coupling agent with surface grafting catalyst, respectively. A fracture mechanics approach has been adopted by mode I test and the effects of specimen geometry have been investigated. Increase in interlaminar fracture energy value, G, was observed as the crack propagated through the composite, i.e. a rising 'R-curve' for both blend and nanocomposites. Deep fracture studies were carried out at different temperatures (−60 °C to 60 °C) using Izod impact and SENT tests. Fracture energy, fracture stress and brittle ductile transition were determined from crack initiation and propagation process, which showed significant improvement in impact and fracture energy at positive temperature. The wide-angle X-ray diffraction (XRD) patterns showed increased d-spacing of clay layers, indicating enhanced compatibility between PP and clay with the addition of maleated polypropylene (MAPP). Morphology/impact property relationships and an explanation of the toughening mechanisms were made by comparing the impact properties with scanning electron micrographs (SEMs) of fracture surfaces. The transmission electron microscopy (TEM) photomicrographs illustrated the intercalated and partially exfoliated structures of the hybrids with clay, MAPP and elastomer. [ABSTRACT FROM AUTHOR]

Polylactic acid (PLA) nanocomposites were prepared using melt blending technique. Two different commercially available nanoclays, Cloisite 93A (C93A) and Cloisite 30B (C30B) at various wt%, have been used to prepare the nanocomposites. The mechanical properties of the nanocomposites have been studied to evaluate the effect of the nanoclay within the matrix polymer. Mechanical tests revealed an increase in the mechanical properties with the incorporation of organically modified nanoclays as compared with PLA matrix. PLA/C30B nanocomposites exhibited optimum tensile modulus at 3 wt% of clay loading. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) studies were also performed to evaluate the thermal behavior of the nanocomposites. Further, viscoelastic behavior in the nanocomposites has been investigated using dynamic mechanical analysis (DMA) to study the damping behavior of the materials. Also the morphological study was carried out through X-ray diffraction analysis, and a better exfoliation or dispersion of C30B clay with PLA matrix was observed. The interaction between the clays and PLA matrix has also been studied using transmission electron microscopy (TEM). [ABSTRACT FROM PUBLISHER]

Organically modified montmorillonite (OMMT) has been incorporated up to 7 wt% in poly(3-hydroxybutyrate) (PHB) by melt compounding in a twin screw extruder. PHB nanocomposites reinforced with C93A showed significant increase in tensile and flexural modulus and impact strength comparatively. Wide angle X-ray diffraction showed an increase in overall d-spacing indicating intercalated structure. The intercalation morphology was further supported by transmission electron microscope images indicating formation of intercalated structure in case of PHB/OMMT and a mixture of Intercalated/exfoliated structure in case of PHB/TMI-MMT nanocomposites. Thermogravimetric analyses indicate that the thermal stability of PHB/TMI-MMT nanocomposites is higher among all other nanocomposites under investigation and virgin PHB. Differential scanning calorimetry (DSC) analysis of PHB nanocomposites shows marginal increase in glass transition temperature and decrease in crystallization temperature compared to virgin PHB. The isothermal crystallization kinetics of PHB/C93A nanocomposites was investigated by DSC in the temperature range of 100-120°C and the development of relative crystallinity with the crystallization time was analyzed by Avrami equation. POLYM. COMPOS., 35:999-1012, 2014. © 2013 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

A new approach of oxidation of carbon nanotubes has been used to oxidize the CNTs. A comparative aspect of the mechanical oxidation and acid oxidation process has been established. FTIR analysis and titration method have shown the higher feasibility of the mechanical oxidation method to oxidize the CNTs. Comparatively less damage to the CNTs has been observed in case of mechanically oxidized as compared to acid oxidized CNTs. The mechanical properties of the nanocomposites reinforced with the acid oxidized CNT (ACNT) and mechanically oxidized CNTs (McCNT) were analyzed and relatively higher properties in the nanocomposites reinforced with McCNT were noticed. The less degree of entanglement in the McCNTs was noticed as compared to ACNTs. The dynamic mechanical analysis of the nanocomposites revealed much improved load transfer capability in the McCNT reinforced composites. Further, the rheological properties of the nanocomposites revealed the higher performance of McCNT reinforced composites. [ABSTRACT FROM AUTHOR]

The present study is related to the investigation of flammability properties of poly(methyl methacrylate) (PMMA) after incorporation of clay. PMMA/layered silicate (nanoclay) nanocomposites with 5% loading of nanofiller were prepared using melt intercalation technique. Commercially modified nanoclays such as Cloisite 30B, Cloisite 93A and in-house modified nanoclay (Quaternary ammonium salt modified Na-MMT i.e. OTAB-Na-MMT have been used as organoclays for the preparation of nanocomposites. Thermal characterization of the above prepared nanocomposites was carried out by thermal conductivity, horizontal burning test (UL94HB) and cone calorimeter experiments. The morphological behavior of nanocomposites was characterized by wide angle x-ray diffraction technique. The morphology of charred material obtained after burning was investigated using scanning electron microscopic analysis. [ABSTRACT FROM AUTHOR]

Polycarbonate (PC)/nanosilica (nSiO2) nanocomposites were prepared by melt-blending technique, in which surfactants are used to enhance the interfacial adhesion between nSiO2 and polymer matrix. Mechanical properties demonstrate increased Young's modulus and yield strength of modified PC/nSiO2 nanocomposites when compared with PC. Increased compatibility further indicates an effective increase in thermal stability as observed from thermogravimetric analysis. Dynamic mechanical analysis point out a reduction in Tg value with increased storage modulus. The flammability characteristics of PC/nSiO2 nanocomposites were evaluated using limiting oxygen index, whereas the morphological properties are characterized by wide-angle X-ray diffraction and scanning electron microscopy. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Polylactide/organically modified layered silicate nanocomposites were fabricated using melt blending technique in a twin screw extruder. Variation in mechanical properties and thermal stability with the addition of three types of commercial nanoclays namely Cloisite 15A, Cloicite 25A, Cloicite 93A in polylactide were investigated. It was observed that the tensile, flexural and impact properties of polylactide increase with increase in organically modified layered silicate from 1 to 7 wt%. Nanocomposites prepared with 5 wt% organically modified layered silicate exhibited optimum mechanical performance. Polylactide/C93A nanocomposites exhibited optimum mechanical performance as compared with virgin polylactide. Dynamic mechanical analysis indicated an increase in storage modulus (E′) with the incorporation of organically modified organoclays. Differential scanning calorimetry and thermogravimetric analysis thermogram in the nanocomposites also showed improved thermal stability when compared with virgin polylactide. X-ray diffraction studies showed an increase in overall d-spacing in polylactide/C93A nanocomposites indicating intercalated structure. [ABSTRACT FROM PUBLISHER]

Banana-fiber-reinforced polypropylene nanocomposites were prepared with a melt-blending technique followed by compression molding. The thermal stability and fire retardancy of the fiber-reinforced nanocomposites was studied as a function of the variable weight percentages of fibers and nanoclays with both thermogravimetric analysis (TGA) and cone calorimetry measurements. The test results indicated char formation at relatively low loadings of the nanoclays, thereby indicating flame retardancy in the fiber-reinforced nanocomposites. The change in the degradation pathway of the polymer was observed with the incorporation of clay within the natural-fiber-reinforced composite, wherein the clay layers acted as barriers to mass transport that contributed to superheated conditions in the condensed phase. TGA thermograms also revealed improved thermal properties compared with the virgin matrix. Both the isothermal and nonisothermal degradation kinetics of the fiber-reinforced nanocomposites were also studied. Differential scanning calorimetry studies showed an increase in the melting and crystallization temperatures of PP in the fiber-reinforced nanocomposites. Furthermore, the morphology of the fiber-reinforced nanocomposites was evaluated with X-ray diffraction and transmission electron microscopy, respectively. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]

Banana fiber-reinforced nanocomposites were fabricated by melt mixing in a twin-screw extruder followed by compression molding in this study. Maleic anhydride polypropylene copolymer (MA-g-PP) was used as a compatibilizer to increase the compatibility between the PP matrix, clay, and banana fiber to enhance exfoliation of organoclay and dispersion of fibers into the polymer matrix. Variation in mechanical, thermal, and physico-mechanical properties with the addition of banana fiber into the PP nanocomposites was investigated. It was observed that presence 3 wt% of nanoclay and 5 wt% MA-g-PP within PP matrix results in an increase in tensile and flexural strengths by 41.3%, and 45.6%, respectively, compared with virgin PP due to the high aspect ratio of clay stacks in the fully exfoliated nanocomposites. Further, incorporation of 30 wt% banana fiber in PP nanocomposites system increases the tensile and flexural strengths to the tune of 27.1%, and 15.8%, respectively. The morphology of fiber-reinforced PP nanocomposites has been examined using scanning and transmission electron microscopies. Significant enhancement in thermal stability of nanocomposites was also observed due to the presence of nanoclay under thermogravimetric analysis. Dynamic mechanical analysis tests revealed an increase in storage modulus (E′) and damping factor (tan δ), conforming the strong interaction between nanoclay/banana fiber and MA-g-PP in the fiber-reinforced nanocomposites systems. [ABSTRACT FROM AUTHOR]

The effect of various sulfonating agents (Chlorosulfonic acid and Trimethylsilylchlorosulfonate (TMSCS) on the performance of Polysulfone (PSU) nanocomposite membranes was investigated. FTIR and 1H NMR results confirmed the sulfonation reaction. Sulfonation of PSU as well as incorporation of Cloisite 30B (C30B) as a filler, resulted in an increase of proton conductivity, water uptake and glass transition temperature (Tg). Thermogravimetric analysis (TGA) exhibited a decrease in decomposition temperature with sulfonation.XRD confirmed positive interaction between C30B and SPSU. Surface and cross-sectional morphology of the membranes were studied using SEM. [ABSTRACT FROM PUBLISHER]

Natural fiber-reinforced polypropylene (PP) nanocomposites at different weight percentages of fiber content were fabricated using a Haake twin screw extruder, followed by compression molding with the presence maleic anhydride grafted polypropylene (MA-g-PP) as a compatibilizer. Incorporation of both the fibers and nanoclay into PP matrix resulted in an increase in mechanical properties with an increasing level of fiber content up to 30 wt% and 3 wt% of nanoclay with 5 wt% of compatibilizer. The morphology of the fiber-reinforced PP-nanocomposites has been examined by using X-ray diffraction (XRD), Scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. [ABSTRACT FROM AUTHOR]