Incorporation Of Nanoclay Research Articles

Manipulation of the properties of PLA nanocomposites by controlling the distribution of nanoclay via varying the acrylonitrile content in NBR rubber

Nanocomposites based on blends of polylactide (PLA), acrylonitrile butadiene rubber (NBR) and 4 wt% organically modified nanoclay (Cloisite 10A) were prepared via melt compounding. To investigate the influence of NBR acrylonitrile (ACN) content on the dispersion state and localization of nanoclay and micromorphology of the blends, three different NBRs with low (19%), medium (33%) and high (51%) ACN content were employed. Nanocomposites with low ACN NBR exhibited higher dispersion of clay nanolayers within the PLA matrix, whereas increase in ACN content gave rise to the localization of silicate platelets within the interface of two phases which was consistent well with the enhanced interfacial interaction between PLA and NBR phases that was evidenced by surface tension and melt rheology analysis. The size of dispersed NBR droplets decreased by the incorporation of organoclay into the composition of all PLA/NBR blends irrespective of the ACN content. However, the reduction in NBR droplet size by the nanoclay layers showed to be more pronounced for the nanocomposites based on high ACN rubber phase as a result of higher localization of nanoclay platelets within the interface of the PLA and NBR. All nanocomposites exhibited significant increase in elongation at break than simple blend counterparts, implying intensification of PLA and NBR interface by nanoclay incorporation.

Effect of unmodified and modified montmorillonite on the properties of PCL based ultrafiltration membrane for water treatment applications

This work presents the preparation of membranes using polycaprolactone (PCL), a biodegradable polymer incorporating unmodified and modified nanoclay using phase inversion technique. The membranes prepared with the incorporation of 0.1g to 0.4g of unmodified nanoclay and 0.05 g to 0.15g of modified nanoclay were studied with respect to porosity, hydrophilicity, chemistry, mechanical and thermal properties and morphological characteristics. The results showed that the membrane incorporated with unmodified nanoclay has enhanced strength and porosity compared to the membrane with modified nanoclay and neat PCL. An increase in water permeability is shown by the incorporation of unmodified nanoclay and contact angle measurement results revealed an increased hydrophilicity with a decrease in membrane roughness which was confirmed using AFM analysis. The surface morphology was examined using SEM analysis and the results revealed that on adding unmodified nanoclay, the average pore size decreased from 6.2μm to 4.5μm and for membranes with modified nanoclay, the average pore size was found to be 1μm. The prepared membranes were tested for the rejection of Congo Red and the performance were analysed.

Influence of Montmorillonite Nanoclay Content on the Optical, Thermal, Mechanical, and Barrier Properties of Low-Density Polyethylene

AbstractAlthough low density polyethylene (LDPE) has long been widely used in packaging applications, some limitations in its use still exist and are due to its relatively poor gas barrier properties and low mechanical strength which can restrict its extensive use for more advanced applications, such as electronic and pharmaceutical packaging. The purpose of this study was to investigate the possibility of using montmorillonite (MMT) nanoclay as a means to enhance the thermal, mechanical, and barrier properties of LDPE prepared via melt extrusion. The level of exfoliated dispersion of the MMT nanoclay in the prepared LDPE-MMT composite was confirmed using transmission electron microscopy (TEM). The relationship between the resulting morphology and the thermal, mechanical, and barrier properties as a function of the MMT content was evaluated. The results showed that incorporating >3 wt.% of MMT nanoclay produced significant changes in the morphology of the LDPE-MMT nanoclay composite in that the segregated matrix adopted an oriented arrangement of exfoliated clay platelets. Thermogravimetric analysis (TGA) showed that the thermal stability of LDPE improved significantly as a result of MMT nanoclay incorporation. Furthermore, differential scanning calorimetry (DSC) analysis indicated that increasing clay content above 3 wt.% effectively reduces the crystallinity of LDPE-MMT composites through the suppression effect. The tensile strength of LDPE increased gradually with an increased content of MMT nanoclay and the maximum value of 16.89 N/mm2 was obtained at 10 wt.% MMT content. This value represents a 40.87% increase relative to the tensile strength of the pristine LDPE. Barrier properties of LDPE and LDPE-MMT nanoclay composites were assessed by examining the permeability with respect to oxygen and water vapor. As the content of MMT nanoclay was increased to 10 wt.%, the permeability of the nanocomposite films to oxygen and water vapor notably decreased to 42.8% and 26.2%, respectively.

Nanoclay decorated polyacrylic acid/starch hybrid nanocomposite thin films as packaging materials

Nanoclay reinforced starch‐co‐PAA hybrid nanocomposite thin films are synthesized by in situ polymerization technique in aqueous solution. The interactions of clay with starch‐co‐PAA are studied by Fourier transform infrared spectroscopy (FTIR) and X‐ray diffraction (XRD). The morphology of nanoclay platelets in starch‐co‐PAA hybrid nanocomposite thin film is studied by scanning electron microscope (SEM) and high‐resolution transmission electron microscope (HRTEM) images are used to investigate micro and nanostructural behavior of clay platelets in starch‐co‐PAA matrix. It is noticed that, the thin film has an exfoliated structure at 3 wt% clay loading whereas; clay platelets are agglomerated in higher percentage of clay. The synthesized materials have chemical resistance of 22% more than the virgin matrix. The biodegradable properties of the nanocomposite thin films are reduced by 20% due to incorporation of nanoclay. The oxygen barrier property of starch‐co‐PAA/clay thin film is reduced by seven folds as compared to starch‐co‐PAA. From the measurement of refractive indexes, it is found that, the transparency of the nanocomposite thin films are reduced by around 10% by reinforcement of nanoclay. The results show a substantial enhancement in oxygen barrier property and reduction of refractive index on clay loading, which may permit the synthesized materials suitable for packaging applications. POLYM. COMPOS., 40:229–239, 2019. © 2017 Society of Plastics Engineers

Effect of nanoparticles on the hydrolytic degradation of PLA-nanocomposites by water-ethanol solutions

Hydrolytic degradation of poly(lactic acid) (PLA-C) and PLA-nanocomposite produced with organomodified montmorillonite at 5 wt% (PLA-OMMT) were investigated in pure water, 50% and 95% ethanol solutions at 40 °C. The change in molecular weight, crystallinity, release of lactic acid (LA), and release of the organomodifier (QAC) were monitored. Ethanol sorption and glass transition temperature (Tg) vs ethanol fraction content were determined. Release of Al as a nanoclay marker was studied when PLA-OMMT was exposed to 50% ethanol solution. PLA-C and PLA-OMMT films had faster hydrolysis in 50% ethanol than in 95% ethanol and water. The incorporation of nanoclay did not have an effect on the hydrolytic degradation. The nanoclay doubled the sorption of ethanol into the film due to the sorption of ethanol into the nanoclay galleries. The nanoclay also acted as an anchor, restricting the movement of the polymer chains as evidenced by the ΔTg and the crystallization behavior. Hydrolysis of PLA-C and PLA-OMMT was related with the release of LA during exposure. The release of QAC from PLA-OMMT films was higher in 95% ethanol at the early stages, but then it exponentially increased in 50% ethanol due to the faster hydrolytic degradation. The clay released from PLA-OMMT films during hydrolysis in 50% ethanol was 0.58% wt. at 90 d of the initial amount of nanoclay in the PLA film.

Introduction of nanoclay-modified fiber metal laminates

In this paper we aim to introduce benefits in modification of epoxy resin of fiber metal laminates (FMLs) with mineral nanoclay platelets. FMLs with carbon fibers and aluminum metal were attached by epoxy resin modified with various amounts of nanoclay. Elastic properties and interfacial toughness of fabricated FMLs were obtained for different percentages of nanoclay incorporation. Results reveal that the interfacial fracture toughness of the FML increases approximately double-fold by 0.5 wt% incorporation of nanoclay. This is attributed to the exfoliation of nanoclay (suggested by XRD) and toughening of the resin by crack blunting mechanism (suggested by SEM).

Nanoclay-Reinforced Glass-Ionomer Cements: In Vitro Wear Evaluation and Comparison by Two Wear-Test Methods.

Glass ionomer cement (GIC) represents a major transformation in restorative dentistry. Wear of dental restoratives is a common phenomenon and the determination of the wear resistance of direct-restorative materials is a challenging task. The aim of this paper was to evaluate the wear resistance of novel glass ionomer cement by two wear-test methods and to compare the two wear methods.The wear resistance of a conventional glass ionomer cement (HiFi Advanced Health Care Kent, UK) and cements modified by including various percentages of nanoclays (1, 2 and 4 wt %) was measured by a reciprocating wear test (ball-on-flat) and Oregon Health and Sciences University’s (OHSU) wear simulator. The OHSU wear simulation subjected the cement specimens to three wear mechanisms, namely abrasion, three-body abrasion and attrition using a steatite antagonist. The abrasion wear resulted in material loss from GIC specimen as the steatite antagonist forced through the exposed glass particles when it travelled along the sliding path.The hardness of specimens was measured by the Vickers hardness test. The results of reciprocation wear test showed that HiFi-1 resulted in the lowest wear volume 4.90 (0.60) mm3 (p < 0.05), but there was no significant difference (p > 0.05) in the wear volume in comparison to HiFi, HiFi-2 and HiFi-4. Similarly, the results of OHSU wear simulator showed that the total wear volume of HiFi-4 1.49 (0.24) was higher than HiFi-1 and HiFi-2. However, no significant difference (p > 0.05) was found in the OHSU total wear volume in GICs after nanoclay incorporation. The Vickers hardness (HV) of the nanoclay-reinforced cements was measured between 62 and 89 HV. Nanoclay addition at a higher concentration (4%) resulted in higher wear volume and wear depth. The total wear volumes were less dependent upon abrasion volume and attrition volume. The total wear depths were strongly influenced by attrition depth and to some extent by abrasion depth. The addition of nanoclay in higher wt % to HiFi did not result in significant improvement in wear resistance and hardness. Nonetheless, wear is a very complex phenomenon because it is sensitive to a wide number of factors that do not necessarily act in the same way when compared using different parameters.

Polyurethane/clay nanocomposites reinforced with carbon and glass fibres: study of mechanical and thermal properties, and the effect of electron beam irradiation

ABSTRACTPolyurethane (PU) nanocomposites with 0, 1, 3, 5, and 7 wt-% nanoclay contents were prepared. X-ray diffraction patterns, transmission electron microscopy images, tensile test, and thermogravimetric analysis were utilised to reveal the morphological, mechanical, and thermal-resistant properties of the prepared nanocomposites. The exfoliated structure was obtained for nanoclay contents up to 3 wt-%. Incorporation of nanoclay to the PU matrix prompted the thermal stability of the polymer. A nanocomposite filled with 3 wt-% nanoclay showed the best tensile strength in the prepared nanocomposites. Subsequently, the nanocomposite with the 3 wt-% nanoclay was reinforced with carbon and glass fibres. Reinforcement of the PU/nanoclay matrix with carbon and glass fibres significantly ameliorated the tensile properties. Finally, the effects of the electron beam irradiation on the nanocomposites and fibre-reinforced composites were studied. Irradiation with the doses up to 500 kGy enhanced the mechanical and thermal properties. However, further irradiation deteriorated the mechanical and thermal-resistant properties.

Preparation and Properties of Halloysite Nanotubes/Poly(ethylene methyl acrylate)-Based Nanocomposites by Variation of Mixing Methods

ABSTRACTHalloysite nanotube-based inorganic–organic polymer nanocomposite has been developed with improved mechanical strength in one direction by solution mixing followed by melt mixing. Melt mixing, solution mixing, and melt-cum-solution mixing were performed to optimize the mechanical strength of the nanocomposites. The field emission scanning electron microscopic images and small-angle X-ray scattering spectrum can support the unidirectional array of halloysite nanotubes in the matrix. The tensile properties revealed that solution–melt mixing is the most desired way to develop clay-based nanocomposites. Thermal characterizations implied that thermal stability was improved after nanoclay incorporation. Dynamic mechanical analysis showed the flow properties and the “Payne effect” of the nanocomposites.

Thermal protection characteristics of polydimethylsiloxane-organoclay nanocomposite

Polydimethylsiloxane (PDMS) polymers are promising candidates as thermal protection systems (TPS) for aerospace applications. In the present study, incorporation of organically modified nanoclay has been successfully employed to improve the properties of PDMS. The effect of 2% w/w of nanoclay on the mechanical and dynamic mechanical properties, thermal, flammability, and thermo-physical properties, hydrophobicity, gas permeability and erosion resistance characteristics of PDMS is investigated. XRD and TEM analyses reveal intercalated to exfoliated morphology for the nanocomposite. Mechanical properties, thermo-oxidative stability, limiting oxygen index, hydrophobicity and permeability show an increasing trend with nanoclay inclusion; whereas, thermo-physical properties remain unaffected. When compared to unmodified PDMS, the ablative properties viz. erosion rate, mass loss rate and heat of ablation of the nanocomposite are more favorable for application as TPS. Also, a substantial reduction in back wall temperature is obtained with the incorporation of nanoclay. This study demonstrates that PDMS-nanoclay composite has a promising potential as TPS for aerospace applications.

Physicochemical properties of nanocomposite films made from sorghum‐oxidized starch and nanoclay

The aim of this study was to evaluate the incorporation of nanoclay in the polymer matrix of native and oxidized sorghum starches films. The nanocomposite films were prepared by the casting technique and the physicochemical, water vapor barrier, mechanical, and morphological properties, as well the contact angle with water and the distribution of the nanoclay in the film were evaluated. The oxidized starch films showed a higher tensile strength, stiffness, and angle of contact with water, as well as a greater morphological homogeneity on the cross section when compared to native starch films. The nanoclay resulted in a significant (p ≤ 0.05) decrease in tensile strength, elongation, and stiffness in the films. The water vapor permeability was reduced with the addition of nanoclay to the native starch films; however, the oxidized starch film did not change. The nanoclay in the native starch films increased the contact angle from 19.2 to 26.1° at 7.5% of nanoclay. However, in the oxidized starch films the contact angle reduced from 29.1 to 18.3° with 7.5% of nanoclay and increased the presence of microfissures. The sorghum starches and nanoclay films have good potential for use in packaging, due to the good water vapor barrier, morphological properties, and an overall good appearance. The addition of nanoclay in sorghum starch films can contribute to the development of more water‐resistant films to be applied in food with high moisture.

Preparation, characterization and anti-fouling properties of nanoclays embedded polypropylene mixed matrix membranes

Low water flux and high fouling characteristic of most polymeric membranes, such as polypropylene (PP), restrict their widespread application. In order to improve the anti-fouling properties of PP membrane, in this study, nanoclays embedded PP membranes containing 0, 0.5, 1, 1.5 and 2wt.% nanoparticles were fabricated by using thermally induced phase separation (TIPS) method. Also, to achieve an effective dispersion of particles in the membrane matrix, PP-g-MA (PP-grafted maleic anhydride) as a compatibilizer was used. Significant improvement in trends of membranes hydrophilicity, porosity, pure water flux, flux recovery and rejection were observed during filtration of BSA protein solution by embedding nanoclays up to 1.5wt.%. Furthermore, the thermal stability and tensile strength of membranes were improved by increasing the nanoclays loading. Anti-fouling properties of the fabricated membranes were investigated by using Hermia and combined fouling mechanisms during filtration of BSA protein solution, under trans-membrane pressure of 1.5bar. The obtained results showed that the neat PP membrane was prone to fouling strongly which is may be due to the inherent hydrophobic characteristic of PP polymer. However, it was found that incorporation of nanoclays into PP membranes could significantly mitigate fouling and improve the membranes performance.

Incorporation of nanoclay into field latex to develop nanoclay filled dry rubber compounds

Two types of nanoclay filled dry rubber compounds were prepared by incorporating sodium montmorillonite (MMT) into natural rubber (NR) at latex stage. Nanoclay filled rubber sheets prepared by acid co-coagulation (ACC) and acid free co-coagulation (AFCC) rubber production methods were milled and compounded to develop nanoclay filled dry rubber compounds. The MMT loading was varied from 0 to 20 phr. Both the above methods are not used as filler incorporation methods in dry rubber industry. AFCC rubber vulcanisates, compared to ACC rubber vulcanisates showed improved mechanical properties mainly due to increased crosslink density associated with the presence of natural accelerators and nano-scale dispersion obtained under acid free environment. The AFCC method is proposed as a new route in filler incorporation, which shows the best mechanical properties at a MMT loading of 8 phr. At higher MMT loadings, due to the formation of aggregated clay structures associated with filler-filler interactions, tensile strength and elongation at break decreased. Modulus and hardness increased with the increase of MMT loading, while tear strength remained unchanged. XDR deffractograms and SEM images revealed that the AFCC rubber at optimum loading has partially exfoliated clay structures with fine phase morphology. DSC analysis revealed that no significant rubber-filler interactions are formed in the rubber vulcanisates.

Study the effects of Cloisite15A nanoclay incorporation on the morphology and gas permeation properties of Pebax2533 polymer

ABSTRACTIn this study, mixed matrix membranes (MMMs) were prepared using commercially available poly(ether‐b‐amide) (Pebax2533) as polymer matrix and organically modified montmorillonite (OMMt) as filler with the aim of investigating their gas permeation properties. The prepared membranes were characterized by Fourier‐transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), scanning electron microscope (SEM), thermal gravimetric analysis, and tensile strength analyses. Gas permeation properties of all the prepared membranes were evaluated at different pressures and clay loadings. Results of FTIR and SEM confirmed the appropriate adhesion between polymer and nanoclays so that no void formation was observed in the polymer/clay interface. XRD results showed that in low loading, clay dispersion occurred as exfoliated‐intercalated and at high loading as intercalated‐phase separated. Results of gas permeation test showed that by adding layered and impermeable clay particles to the polymer matrix, the permeation of soluble CO2 gas reduced by 28% for the highest clay loading. By increasing of pressure from 2 to 6 bar, CO2/CH4 permselectivity increased at all nanoclay loadings. The highest CO2/CH4 selectivity was obtained for 6 wt % clay MMM at all pressures, while the highest CO2/H2 selectivity was achieved for neat polymer at 6 bar. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45302.

Production and characterization of a new biodegradable fenugreek seed gum based active nanocomposite film reinforced with nanoclays

In the present work, fenugreek seed gum (FSG)/clay nanocomposite films were prepared with nanoclays (Na+ montmorillonite [MMT], halloysite [HNT] and Nanomer® I.44 P [NM]) at different amounts (0, 2.5, 5.0 and 7.5g clay/100g FSG) by solution casting method and characterized. Increasing amount of nanoclay significantly (P<0.05) improved oxygen barrier and thermal properties of the biodegradable films. Agar diffusion tests revealed that FSG based nanocomposite films exhibited strong antimicrobial properties against foodborne pathogens namely Listeria monocytogenes, Escherichia coli O157:H7, Staphylococcus aureus and Bacillus cereus independently of clay type and concentration. In the case of mechanical properties, nanoclay incorporation up to 5% provided higher (P<0.05) tensile strength (TS) properties while elongation at break (EB) values of the films significantly (P<0.05) decreased in the presence of clay in the film matrix. SEM micrographs showed that especially lower levels (up to 5%) of nanoclay reinforcements provided a homogeneous and smooth film structure. In conclusion, FSG based nanocomposite films reinforced with nanoclays up to 5% showed a precious potential to be used in antimicrobial food packaging applications.

Effects of Organo-Modified Clay Addition and Temperature on the Water Vapor Barrier Properties of Polyhydroxy Butyrate Homo and Copolymer Nanocomposite Films for Packaging Applications

Polymer nanocomposites, based on bacterial biodegradable thermoplastic polyester, poly(hydroxy-butyrate) (PHB), poly(hydroxyl-butyrate-co-hydroxy-valerate) (PHBHV), and commercial organo-modified montmorillonite (OMMT-Cloisite 10A) were prepared by solution casting method. This work aims to investigate the effect of Cloisite 10A type clay addition on the water vapour permeability properties of PHB/OMMT, and PHBHV/OMMT nanobiocomposite films. Temperature dependence of water vapor permeabilities of the films were also evaluated at various temperatures, and semi empirical permeability models were used to predict the permeability of polymer systems as a function of clay concentration and aspect ratio of nanoplates. Moreover, thermal, optical, and mechanical properties of the composites were examined by using varieties of techniques including differential scanning calorimeter (DSC), thermogravimetric analyzer (TGA), scanning electron microscope (SEM), and thin-film X-ray diffractometer (TF-XRD) respectively. Test results indicated that addition of highly intergallery swollen Cloisite 10A to the PHB/PHBHV, reduced the water vapor permeability up to 41 and 25% compared to native PHB and PHBHV films, respectively. Regarding the all mechanical properties measured, the maximum improvement was achieved for 3 wt% clay loaded samples for both PHB and PHBHV polymer composites. An increase of about 152 and 73% in tensile strength and of 77 and 18% in strain at break was achieved for PHB and PHBHV polymers, respectively. As a result of X-ray diffraction analysis, exfoliated structure was achieved at low clay loaded sample (1% w/w), however at higher concentration (3% w/w) the structure found as intercalated. Therefore, it is an evident that enhancement of characteristic properties highly depend on the dispersion level of clay particles in polymer matrix. The results obtained in this study show the feasibility of improvement of the properties of PHB based polymers with incorporation of nanoclay.

Electrospun PVDF/MWCNT/OMMT hybrid nanocomposites: preparation and characterization

Electrospinning technique was employed to prepare neat PVDF, nanoclay-PVDF and carbon nanotube (MWCNT)-PVDF nanocomposites, and nanoclay-carbon nanotube-PVDF hybrid nanocomposites. A mixture of dimethyl formamide/acetone (60/40) was used to fluidize the polymer and nanofillers. Electrospinning process was conducted under optimized conditions. Maximum modification was achieved at 0.15 wt% nanofiller. Rheological measurements on the prepared solutions revealed decreased material functions in the presence of nanoclay, whereas the rheological properties of MWCNT-PVDF solution did not show any significant reduction compared with those of neat PVDF solution. The behaviors of the hybrid nanocomposite solutions, though dependent on their composition and their material functions, increased with MWCNT concentration. These differences, together with variations in electrical properties of nanoclay and MWCNT, led to changes in morphology of the fiber during electrospinning process. Under electrospinning conditions designed for neat PVDF solution, mats with beads and with the highest fiber diameter were produced. Meanwhile, incorporation of both nanoclay and MWCNT into the solutions resulted in bead-free fibers with thinner diameter. Fourier transformed infrared spectrophotometry (FTIR) and X-ray diffractometry (XRD) were used to measure the β-phase crystalline content in electrospun mats. Complete agreement was found between the FTIR and XRD results. The lowest and highest β-phase contents were obtained for neat PVDF mat and hybrid nanocomposite mat containing 0.1 wt% clay, respectively. The mixing procedure of nanofillers and the PVDF solution was also found to be important. In case of hybrid nanocomposites, more β-crystals were formed when the nanoclay was first mixed in the absence of MWCNT.

Influences of Functionalized Nanoclays on Morphology and Mechanical Properties of Polyvinyl Alcohol-Based Composites by Twin-Screw Extruder

ABSTRACTPolyvinyl alcohol-based nanocomposites filled with different weight percentage of functionalized nanoclays were prepared by melt processing with a twin-screw extruder. The effective incorporation of amine-modified bentonite nanoclays in the PVA matrix leads to the increase in thermal stability, stress–strain properties. The effect of the addition of functionalized nanoclays in PVA matrix exhibits intercalated nanocomposite structure. The thermal decomposition (Td) temperature of the composites increases up to 30°C, than pristine PVA. The morphology influences were studied by TEM. These clay nanocomposite films could be useful for wound dressing material and for enhancing the moisture absorbance properties.

Experimental study of shrinkage and ejection forces of reinforced polypropylene based on nanoclays and short glass fibers

This study presents the influence of nanoclays and glass fibers on the shrinkage and ejection forces of polypropylene‐based composites for tubular parts produced by injection molding. An instrumented mold was used to measure cavity pressure, surface temperature and ejection forces in the tubular parts during the injection cycle. The materials used for the study were polypropylene homopolymer Domolen 1100L, nanoclays for polyolefin nanocomposites (P‐802 nanoMax, used in percentages of 2%, 6%, and 10%) and reinforced polypropylene homopolymer with a content of 10% and 30% glass fiber (Domolen P1‐013‐V10‐N and Domolen P1‐102‐V30‐N, respectively). Part shrinkage was measured 48 h after production. The results show that the incorporation of nanoclays reduces shrinkage and ejection forces while glass fibers decrease shrinkage and increase ejection forces due to an increase in elastic modulus. Nanoclays decrease the ejection forces when compared to glass fibers and pure PP. The effects of nanoclays are less pronounced than those of glass fibers. Moldings produced with different materials were also analyzed to assess the effect of mold temperature on the ejection forces. Shrinkage rises slightly by increasing the mold temperature while the ejection force decreases. POLYM. ENG. SCI., 58:55–62, 2018. © 2017 Society of Plastics Engineers

Modification of Functional Properties of Whey Protein Isolate Nanocomposite Films and Coatings with Nanoclays

Whey protein based films have received considerable attention to be used for environment friendly packaging applications. However, such biopolymers are prevented for use in commercial packaging due to their limited mechanical and barrier performance. The addition of nanofillers is a common method to overcome those drawbacks of biopolymers. Whey protein isolate (WPI) based nanocomposite cast films and coatings were produced using montmorillonite and vermiculite clay as nanofiller in different concentrations. Uniform distribution of filler within the polymeric matrix was confirmed by scanning electron microscopy. Mechanical properties such as tensile strength as well as Young’s modulus were increased after increasing the filler content, while elongation at break values decreased. All samples showed weak barrier potential against water vapor. Nanoclay incorporation, however, reduced water vapor transmission rates by approximately 50%. The oxygen barrier performance was improved for all nanocomposites. Results also indicated proportionality with the filler ratio according to applied models. The highest barrier improvement factors (BIF) were greater than five for the cast films and even greater than sixteen for the coatings. Developed WPI-based composites depicted nanoenhanced material properties representing a promising alternative to fossil-based packaging films.