Adhesion Improvements of Nanocellulose Composite Interfaces

Attention has recently become focused on the performance advantages of nanocomposites, and particularly polymerbased nanocomposites with respect to incumbent “neat” polymers or metallic materials for lightweighting initiatives. In the interest of sustainability, the specific use of bioreinforced nanocomposite parts and nanostructured coatings within automotive, aerospace, construction, medical, and packaging applications is accelerating. These “green” nanocomposites can provide high mechanical strength at low density, low weight, and potentially low cost. However, there are interfacial surface adhesion challenges with these and other nanocomposites, in addition to particle distribution and stability issues, which can inhibit full realization of their mechanical performance advantages. This paper will profile polymeric nanocomposites and nanocoatings, as well as define surface modification protocols using atmospheric pressure plasma technologies to optimize interfacial adhesion to similar and dissimilar materials.     

Transparent semi-crystalline polymeric materials and their nanocomposites: A review

Optical transparency is an important property for a material, especially in certain fields like packaging, glazing, and displays. Existing commercial transparent polymeric materials are mostly amorphous. Semicrystalline polymers have often-superior chemical resistance and mechanical properties particularly at elevated temperatures or after solid-state drawing but they appear opaque or white in most cases. This review describes the present state-of-the-art of methodologies of fabricating optically transparent materials from semicrystalline polymers. A distinction is made between isotropic, biaxially stretched, and uniaxially stretched semicrystalline polymers. Furthermore, some functionalities of transparent nanocomposites based on semicrystalline polymers are also discussed. This review aims to provide guidelines regarding the principles of manufacturing transparent high-performance semicrystalline polymers and their nanocomposites for potential applications in fields like packaging, building, and construction, aerospace, automotive, and opto-electronics.     

Mechanical and thermal properties of thermoplastic polyurethane‐toughened polylactide‐based nanocomposites

The crystallinity and mechanical and thermal properties of polylactide (PLA)‐based biodegradable‐engineered plastic nanocomposites were determined. The nanocomposites were composed of thermoplastic polyurethane (TPU)‐toughened PLA, Talcum (Talc) and organic modified clay (montmorillonite; OMC). The tensile and flexural tests showed that PLA blended with 10 wt% TPU, 4 wt% Talc powder and 2 wt% OMC had the highest modulus and strength without a loss of elongation. The heat distortion temperature (HDT) tests demonstrated that the thermally treated PLA‐based nanocomposites had an HDT of nearly double the HDT for untreated specimens. An analysis of the polymer using scanning electron microscopy demonstrated that the incorporation of inorganic fillers altered the heterogeneous morphology of the PLA/TPU blend. This study investigated the feasibility of using PLA‐based nanocomposites for practical use, including applications in the automotive and furniture industries. POLYM. COMPOS., 35:1744–1757, 2014. © 2013 Society of Plastics Engineers     

Fabrication of well-controlled porous foams of graphene oxide modified poly(propylene-carbonate) using supercritical carbon dioxide and its potential tissue engineering applications

Poly(propylene carbonate) is a new amorphous, biodegradable and biocompatible aliphatic polyester. It has a potentially wide range of applications, such as packing materials and biomedical materials. However, the low glass transition temperatures (T_g) and poor mechanical property have limited its applications. In this paper, poly(propylene-carbonate)/graphene oxide nanocomposites with a 10 °C increase in T_g and a 50 times increase in storage modulus at 30 °C were firstly fabricated, then the nanocomposites were foamed using supercritical CO₂ to widen their applications, particularly in the area of tissue engineering. It was demonstrated that the nanocomposite foams had good dimension stability and the final pore features were depended on supercritical CO₂ saturation conditions. In addition, cytotoxicity and in vitro cell culturing tests of selected foams showed that the fabricated porous materials were non-cytotoxic and able to support cellular adhesion within the 3D structure, suggesting that these are promising materials for tissue engineering applications.     

Synthesis and characterization of polyester-based nanocomposites coatings for automotive pre-coated metal

Polyester-based nanocomposites coatings were synthesized by the in situ polymerization with high speed homogenizer process at the various contents of organic modified montmorillonite (OMMT) to disperse into the polyester matrix. The dispersion state of organoclay was examined by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The absence of reflection pattern of organoclay and TEM study revealed that organoclay was partially intercalated and exfoliated into the polymer matrix. Mechanical property of polyester-based nanocomposites coatings (PE/OMMT) improved the tensile strength and good formability at the deep drawing test. The viscoelastic behavior of PE/OMMT nanocomposites coatings was observed by dynamic mechanical analysis (DMA). When the content of organoclay was increased, the stiffness of the PE/OMMT nanocomposites coatings increased considerably and T_g of each cured coatings shifted to a lower temperature. Anti-corrosion property was examined by the salt spray test. CNC-3 had little rust after 600 h and it implies that nano-sized layered silicate of organoclay effectively increases the length of the diffusion pathways water molecules. And nano-sized layered silicate of organoclay might be decreased the permeability and could make higher corrosion resistance of PE/OMMT nanocomposites coatings. From those results, CNC-3 had good formability in the deep drawing and also had good anti-corrosion property. So, CNC-3 would be an appropriate coating for automotive pre-coated metal.     

Mechanical,thermal, and morphological properties of graphene reinforced polycarbonate/acrylonitrile butadiene styrene nanocomposites

Nanocomposites of polycarbonate/acrylonitrile butadiene styrene (PC/ABS) with (70/30) composition containing different amounts of graphene nanoplates (GNPs) (1, 3, and 5 wt%) were prepared by melt‐blending in a twin‐screw extruder. The structural, morphological, mechanical, and thermal properties of the nanocomposites were investigated. The Young's modulus and flexural modulus of the nanocomposites were increased by 30 and 54%, respectively, when 3 wt% GNPs was added. The flexural strength and tensile strength of the PC/ABS/GNPs nanocomposites increased up to a loading of 3 wt% GNPs. The incorporation of GNPs enhanced the thermal stability and char yield of the nanocomposites. X‐ray diffraction and field emission scanning electron microscopy showed uniform dispersion and alignment of GNPs in PC/ABS matrix. The interaction between the GNPs and the PC/ABS matrix were confirmed by Fourier transform infrared spectra. Therefore, the PC/ABS/GNP nanocomposites with improved flexural and tensile properties, without loss of extensibility and good thermal properties may have promising applications in automotive, electric tools, household, communication, and safety appliances. POLYM. COMPOS., 37:1633–1640, 2016. © 2014 Society of Plastics Engineers     

Multifunctional hybrid polymer nanocomposites for automotive-battery packaging

Global sales of new electric vehicles (EV) already passed a million units last year. Lithium-ion battery packs are composed of cells and assembly of modules. Nevertheless, the development of light-weighted with high oxygen and moisture barrierability remains one of the untouched issues in battery technology. This study aimed to fabricate multifunctional hybrid nanocomposites for barrier films for Li-ion battery packs on electric vehicles applications. The synthesized carbon supported MgO nanoparticles (hereafter referred to as CSMO) were dispersed in high density polyethylene (HDPE) polymer to satisfy several requirements for EV battery packs. The loading amount of MgO was achieved up to 22 wt % of carbon, and the size distribution was in the range of 50 to 100 nm. The hybrid nanocomposites were characterized by water-vapor transmission rate (WVTR), various spectroscopic methods, thermo-gravimetric analysis and elemental analysis. Mechanical properties were also tested. The extremely low WVTR value of CSMO/HDPE composites below 0.5 mgm⁻² day⁻¹ is the lowest value among any other gas barrier films reported in the literature. Suitable mechanical properties were also achieved. The newly proposed multifunctional hybrid nanocomposites would be very promising for barrier films on automotive packaging applications.     

Effect of bone ash fillers on mechanical and thermal properties of biobased epoxy nanocomposites

In this study, the fabrication and characterization of bone ash filled biobased epoxy resin (Super SAP 100/1000, contains 37% biobased carbon content) nanocomposites are presented. Biosource bone ash was modified by size reduction and surface modification processes using a combination of ball milling and sonochemical techniques and characterized using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The modified bone ash particles were incorporated into biobased epoxy with noncontact mixing process. The as-fabricated nanocomposites were characterized using various thermal and mechanical analyses. The nanocomposites showed significant improvement in flexural strength (41.25%) and modulus (34.56%) for 2 wt% filler loading. Dynamic mechanical analysis (DMA) results showed improvement in both storage modulus and loss modulus. Additionally, DMA results showed a slight reduction in glass transition temperature which also complies with differential scanning calorimetry results. Thermomechanical analysis results showed a reduction in the coefficient of thermal expansion. Thermogravimetric analysis results showed improved thermal stability at both onset of degradation and the major degradation. These enhanced thermal and mechanical performances of the epoxy nanocomposites allows them to be suitable for lightweight aerospace, automotive, and biomedical applications.     

An overview of the recent advances in polylactide-based sustainable nanocomposites

The article reports recent advances in reference to the existing literature and presents a knowledge gap and potential solution ideas for polylactide (PLA) nanocomposites as sustainable materials. Various types of nanoparticles have been used for the development of PLA nanocomposites; however, this work focuses on PLA nanocomposites of nanoclay, nanocelluloses, carbon nanotube, and graphene. By providing a wholistic overview of the fundamental knowledge pertaining to PLA, and covering all critical aspects related to processing, characterization, and applications of PLA nanocomposites, this review provides a direction for future developments in the field of PLA nanocomposites suitable for various advanced applications, which is still scarce in the literature, including review articles. Moreover, the effects of dispersion/distribution of various types of nanoparticles on the degradation characteristics and special properties, such as cytocompatibility, electrical conductivity, and antimicrobial properties, of PLA nanocomposites are critically reviewed with regard to the nature of nanoparticles used for nanocomposite formation. In summary, this review provides new insight into the design and formulation of advanced PLA nanocomposites for a wide range of applications as sustainable materials.     

The Influence of Sepiolite Orientation and Concentration,on the Morphological,Thermal and Mechanical Properties of Bio-Polyamide 4.10 Nanocomposites

Nowadays, trends in automotive sector are toward high-performance materials, but also the concern about the environment has become an important driver for car manufacturers. In this sense, reinforced polymers are lightweight materials that can replace metals in some structural applications with an outstanding contribution to reduce the carbon dioxide emissions. In short fiber-reinforced polymers, processed by injection molding, the fibers are oriented in multiple and arbitrary directions. Due to the arrangement of the fibers, these materials present different thermomechanical behavior. In this study, bio-polyamide 4.10/sepiolite (0–15 wt%) nanocomposites obtained by melt compounding were injected using a square plate mold. Specimens were mechanized in different directions (0°, 45°, and 90°) from this square plate and morphologically and thermomechanically tested. The sepiolite reinforcement results showed improvement in the thermomechanical properties. Moreover, despite the nanometer size of the reinforcement, the mechanical properties were also dependent on the fiber orientation during the injection molding of the nanocomposites. POLYM. ENG. SCI., 60:1035–1043, 2020. © 2020 Society of Plastics Engineers     

Stretchable,mechanically resilient,and high electromagnetic shielding polymer/MXene nanocomposites

The increasingly disturbing electromagnetic wave pollution has intensified research for high-performance shielding materials to protect humans and the environment. It remains a great challenge to combine high electromagnetic interference (EMI) shielding performance with mechanical robustness and stretchability. These crucial features have been simultaneously achieved in this work by using a facile method to prepare elastomer/MXene nanocomposites. An EMI shielding effectiveness of 49 dB was obtained from a 1-mm thick nanocomposite film at 19.6 vol% of MXene; the film has a density of 1.25 g/cm³. The outstanding electrical conductivity of MXene – 4350 ± 125 S·cm⁻¹ – provided free charge carriers in the matrix to absorb electromagnetic signals, leading to the dominance of absorption mechanism over reflection mechanism. Owing to a nanofiller modification step, the nanocomposite films demonstrated not only outstanding EMI shielding but sufficient strength and stretchability. A nanocomposite at 14.0 vol% exhibited Young's modulus of 15.85 ± 0.75 MPa and tensile strength 25.94 ± 0.81 MPa with elongation at break of 170 ± 5.6%, which relates to high stretchability. These impressive properties make our nanocomposites suitable for use in harsh environments as well as applications in stretchable devices, protective clothing, aerospace, aircraft, and automotive industries.     

Thermostable and flame retardant Mesua ferrea L. seed oil based non-halogenated epoxy resin/clay nanocomposites

Bio-based polymer nanocomposites have a unique niche of their own in the domain of green technology. A bio-based sulfone epoxy resin (BPSE) has been synthesized from the monoglyceride of Mesua ferrea L. seed oil, bis(4-hydroxyphenyl) sulfone, bisphenol-A and epichlorohydrin. The formation of resin was confirmed by the determination of viscosity, epoxy equivalent, etc. and the structure was elucidated from FTIR and ¹H NMR spectroscopies. This resin was used as the matrix for the preparation of epoxy/clay nanocomposites by ex situ technique using different doses of organo nano-clay (1, 2.5 and 5%, w/w). XRD, TEM, SEM, FTIR and rheological studies confirmed the formation of nanocomposites with partial exfoliated structure of the nano-clay. The study demonstrated that the tensile strength enhanced from 4 to 11.4 MPa, scratch hardness improved by two-fold, gloss value increased by 20 units, adhesive strength improved by two-fold and thermal stability improved by 19 °C on incorporation of 5 wt% of nano-clay with respect to the pristine polymer. The limiting oxygen index value and UL94 test indicated improvement of flame retardancy of the nanocomposites. The results exhibit the potentiality of these bio-based epoxy/clay nanocomposites for multifaceted advanced applications.     

Some recent advances in polyolefin functionalization

Polyolefin‐based materials are increasingly being used in many industrial applications for packaging, automotive and construction materials. The recent developments of research have been aimed at making these materials, often complex, being mixtures, block copolymers, micro‐ and nanocomposites with inorganic and organic fillers, more efficient and environmentally friendly (through recycling processes, and the use of bio‐polyolefins). In this context, functionalized polyolefins, on the one hand, play a fundamental role in improving the morphology and thus the thermal and mechanical properties of heterophase systems, and, on the other hand, provide new materials difficult to obtain by conventional synthesis in connection with the type of inserted functionality. Therefore it appears to be of interest to report and discuss here the recent results concerning the radical grafting in the melt of different functionalities onto polyolefins as well as the capability reached of modulating ad hoc the degree of grafting and the final structure/architecture of functionalized polyolefins. © 2013 Society of Chemical Industry     

Preparation and characterisation of polyamide–polyimide organoclay nanocomposites

BACKGROUND: Ternary nanocomposites containing an organomodified layered silicate polyimide additive within a polyamide matrix have been investigated to gain greater insight into structure–property relationships and potential high‐temperature automotive applications. RESULTS: Polyamide nanocomposite blends, containing 3 wt% of organoclay, were prepared and compared with organoclay‐reinforced polyamide and neat polyamide. Nanoclay addition significantly increased heat distortion temperature, as well as both the tensile and flexural moduli and strength. The addition of polyimide demonstrated further increases in heat distortion temperature, glass transition temperature and the flexural and tensile moduli by about 17, 21 and 40%, respectively. The tensile and flexural strengths were either unaffected or decreased modestly, although the strain‐to‐failure decreased substantially. Morphological studies using transmission electron microscopy (TEM) and X‐ray diffraction showed that the nanoclay was dispersed within the ternary blends forming highly intercalated nanocomposites, regardless of the presence and level of polyimide. However, TEM revealed clay agglomeration at the polyamide–polyimide interface which degraded the mechanical properties. CONCLUSIONS: A range of improvements in mechanical properties have been achieved through the addition of a polyimide additive to a polyamide nanocomposite. The decrease in ductility, arising from the poor polyamide–polyimide interface and nanoclay clustering, clearly requires improving for this deficiency to be overcome. Copyright © 2008 Society of Chemical Industry     

Newly emerging applications of halloysite nanotubes: a review

Halloysite nanotubes (HNTs) are types of naturally occurring 1:1 clays with nanotubular structures and similar chemical composition to kaolin. Due to various characteristics such as nanoscale lumens, high length‐to‐diameter ratio, relatively low hydroxyl group density on the surface, etc., numerous exciting applications have been discovered for this unique, cheap and abundantly deposited clay. After briefly summarizing applications in controlled release, nanotemplating and sorption, we emphasize the applications of HNTs in the fabrication of polymer nanocomposites. The unique structures and performance of HNT‐incorporated polymer nanocomposites processed by various routes are described. The results suggest that these nanocomposites exhibit remarkable performance such as reinforcing effects, enhanced flame retardancy and reduced thermal expansion. Accordingly, HNTs should be of interest in the area of polymer nanocomposites for structural and functional applications. Copyright © 2010 Society of Chemical Industry     

Structural,Mechanical and Biological Insights on Reduced Graphene Nanosheets Reinforced Sonochemically Processed Nano‐Hydroxyapatite Ceramics

In this study, we have attempted to prepare reduced graphene nanosheets (RGNS) reinforced nano-hydroxyapatite (nHAp) nanocomposites via different sonochemical treatments of nHAp. Structural properties of RGNS-nHAp nanocomposites were investigated by XRD and Raman analysis. In vitro bioactivity of RGNS-nHAp nanocomposites were examined by immersing them in hank's balanced salt solution and further in vitro apatite layer formation was confirmed by systematic investigations using FESEM and ICP-OES analyses. Interactions of RGNS, pure nHAp and their nanocomposites with human erythrocytes were explored. Hemocompatibility of BGO-nHAp nanocomposites were found to be superior to pristine RGNS. The nanocomposites were mechanically improved when compared to nHAp through effective load transfer onto their 2D lattice of RGNS. However, 20PGO-nHAp nanocomposites were mechanically weaker than 20BGO-nHAp due to the formation of β-TCP as an additional phase, thus decreases its mechanical strength.     

Nanocomposites from poly(ethylene-co-methacrylic acid) ionomers: effect of surfactant structure on morphology and properties

A detailed study of the structure-property relationships for nanocomposites prepared using melt processing techniques from a sodium ionomer of poly(ethylene-co-methacrylic acid) and a series of organoclays is reported. Transmission electron microscopy, X-ray scattering, stress-strain behavior, and Izod impact analysis were used to evaluate the nanocomposite morphology and physical properties. Four distinct surfactant structural effects lead to improved levels of exfoliation and higher stiffness for these nanocomposites: higher number of alkyl tails on the amine rather than one, longer alkyl tails instead of shorter ones, use of 2-hydroxy-ethyl groups as opposed to methyl groups on the ammonium ion, and an excess amount of the amine surfactant on the clay instead of an equivalent amount. These trends are opposite of what has been seen in nylon 6 based nanocomposites but are similar to those observed in nanocomposites formed from LDPE and LLDPE. Although some organoclays were exfoliated better than others, none of the ionomer-based nanocomposites exhibited exfoliation levels as great as those seen in nylon 6 nanocomposites; nevertheless, these nanocomposites offer promising improvements in performance and may be particularly interesting for barrier applications.     

Akaganeite polymer nanocomposites

An “in situ” method for the production of akaganeite polymer nanocomposites is described. A controlled precipitation is achieved by using a polymer matrix, polyvinylpyridine, containing N-base functional groups that form coordination bonds with iron ions. The resulting materials have permitted the observation of two sources of magnetic moment in akaganeite nanoparticles: (1) finite size effects with a characteristic blocking temperature below 2 K; and (2) a deficient Cl⁻ occupancy, with a characteristic blocking temperature around 18 K. Moreover, the nanocomposites can be dissolved in slightly acidic media to obtain stable aqueous nanoparticle dispersions that could be useful in biomedical applications.     

Effect of blending sequence on microstructure of ternary nanocomposites

Knowledge of the nature of molecular processes occurring during melt compounding of nanomaterials and polymers is crucial in determining the ultimate performance of polymer nanocomposites. In this paper, we demonstrate for the first time with detailed transmission electron microscopy, the parameters that affect the microstructure of polymer nanocomposites by varying the blending sequence. Nylon 66/organoclay/SEBS-g-MA ternary nanocomposites prepared by four different blending sequences exhibited distinct microstructure and mechanical properties. It was concluded that the best microstructure for toughness and other mechanical properties is to have the maximum percentage of the exfoliated organoclay in the nylon 66 matrix rather than to have it in the dispersed SEBS-g-MA phase. The presence of organoclay in the SEBS-g-MA phase reduces the latter's ability to cavitate, resulting in reduced toughening efficiency.