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In contemporary developments across automotive, aerospace, and military industries, there is an ever-growing demand for lightweight and robust polymer composites. In this study, a ductile epoxy resin, carbon nanotubes (CNTs), cellulose nanofibers (CNFs), and silica nanoparticles were used to fabricate nano-fillers/epoxy composites and nano-fillers/silk fibers/epoxy hybrid composites through solution casting and hot pressing. Their mechanical properties and thermal characteristics were analyzed and compared, which show that: these nano-fillers can dramatically enhance the strength and stiffness of the ductile epoxy resin; however, this is achieved at the expense of its toughness and extensibility. CNT/silk fiber/epoxy hybrid composite has the highest tensile strength (81.10 MPa), Young's modulus (3.76 GPa) and impact strength (103.7 kJ/m2), while the CNFs-reinforced one exhibits the highest breaking energy (9.96 MJ/m3). These nano-fillers almost do not affect the thermal stability of the epoxy resin and silk fiber composites. In addition, the fracture modes of their reinforced composites were revealed by macroscopic and microscopic observations. • Reveal how different nano-fillers affect the mechanical behaviors of ductile polymer matrix. • Explore the optimal content of these nano-fillers in the polymer matrix. • Indicate nano-fillers do not affect the thermal stability of their reinforced composites. • Elucidate the composites' fracture modes introduced by silk fibers and different nano-fillers. [ABSTRACT FROM AUTHOR]

In order to manufacture high-speed rubber tracks, it is urgent to develop natural rubber composites with excellent thermal and mechanical properties. In this paper, natural rubber was filled with milled carbon fiber (CF) which was synergistically modified by dopamine and silane coupling agent (SCA), including KH560, KH570 and KH590. Firstly, the polydopamine initial platform was formed on CF surface through self-polymerization of dopamine. Subsequently, SCA was grafted to improve the interface properties between the filler and the matrix. Eventually, the co-modified CF filled natural rubber (CF/NR) was fabricated by mechanical mixing method. The modification process was confirmed by scanning electron microscopy and other characterization methods. The heat build-up, thermal conductivity and mechanical properties of CF/NR were compared. The results showed that SCA could effectively graft on the polydopamine platform, and the thermal and mechanical properties of the three silane functionalized carbon fiber filled natural rubber composites were improved in different degrees. Among them, the carbon fiber grafted with KH590 filled natural rubber had the best comprehensive properties. Concretely, the thermal conductivity increased by 71.3% compared with the unfilled natural rubber, and the tensile strength increased by 73.3%. The improvement of the interfacial interaction of the modified fiber and rubber matrix was considered to be one of the essential reasons. • Dopamine and silane coupling agents are utilized to synergistically modify the milled carbon fibers. • The analysis of "Payne effect" demonstrated that interaction between fillers and matrix was improved after modification. • The improved interfacial interaction inhibits relative displacement and reduces the interface thermal resistance. • Relative to KH560 and KH570, KH590 modified carbon fiber improves thermal and mechanical properties of rubber composite. • Compared with NR, the thermal conductivity of M-CF/NR increased by 71.3%, and the tensile strength increased by 73.3%. [ABSTRACT FROM AUTHOR]

In this study, it was investigated the feasibility of wood-plastic composites (WPCs) made of polylactic acid (PLA), as a biobased thermoplastic matrix material and treated wood flour (Pinus sylestris L.) with Tanalith E, as organic reinforcement of matrix material. The wood flour amounts in composites were 30, 40 and 50 wt% by weight fiber loadings. Maleic anhydrid grafted polyethylene (MAPE) as a coupling agent was also used to improve the compatibility between the fiber and plastic matrix. Density, void content, water absorption, thickness swelling, tensile test, flexural properties, impact strengths, thermal properties, microstructural and morphological characterization and durability against white rot (Trametes versicolor (MAD-697) (L:Fr.) Pilat) and brown rot (Coniophora puteana ((Schumach.: Fr.) P. Karst (Mad-15)) were used to characterize the WPCs properties. Results revealed that WPCs with untreated wood flour had higher densities compared to those of WPCs with treated wood flour for the same wood contents due to higher void content of treated wood flour-PLA composites. In addition, water absorption and thickness swelling rate of WPCs increased with an increasing the fiber content in WPCs. Regarding to mechanical properties, PLA composites with treated wood flour content of 40 wt% showed best mechanical performance among the different fiber contents. The percentage of weight loss and residual ratio increased with increases in both the wood flour content and the temperature. All tested WPCs had lower weight losses than that of control (untreated wood) samples due to encapsulation of wood by biobased thermoplastic matrix. • Characterization of treated wood flour filled PLA composites were determined. • Water absorption and thickness swelling rate of WPCs increased with an increasing the fibre content. • 40 wt% with treated wood flour content showed best mechanical performance. [ABSTRACT FROM AUTHOR]

Abstract The effects on the thermal and mechanical properties of a glass fiber/polyurethane composite for automotive applications exposed to an accelerated aging environment by use of elevated temperatures were assessed in this study. Changes within the material are evaluated in terms of mass variation, and by Dynamic-Mechanical Analysis (DMA), Three-Point Bending (3 PB) tests, and Light Microscopy. Water induces a reversible decrease in glass transition temperature (Tg) due to plasticization of the matrix, while the silicone-based brake fluid (DOT5) slightly improves the mechanical and thermal properties. Significant changes in the material are found when exposed to the glycol-based brake fluid (DOT4) and gasoline, in terms of chemical alterations and delamination. However, the combination of liquids immersion and high temperatures has the most significant impact. The concept of accelerated aging cannot be applied in DOT4 and gasoline since structural changes occur, while in water the prediction made using 'short-term' tests deviates from long-term experimental results. Highlights • Accelerated aging is a good method for rapid identification of the main degradation mechanisms affecting polymer composite. • Structural changes occur in the fiber reinforced polyurethane after exposure to glycol-based brake fluid at 70 °C. • Mechanical properties of composite when exposed to water decrease by water absorption through matrix/fiber interface. • Temperature is the governing factor affecting the mechanical performance. • Increased temperature activates the diffusion of liquids in the composite, thus accelerating its deterioration. [ABSTRACT FROM AUTHOR]

Abstract The three-dimensional (3D) printing technology is changing the modern manufacturing of many pieces due to its versatility, immediacy and reduced cost. Thus, stereolithography (SLA), as one 3D printing technology, is becoming an important method to construct small pieces and, therefore, new materials used for it are still nowadays under study. SLA has numerous drawbacks such as the composition and the chemistry of commercially available materials are unknown, or the lack of knowledge of the physico-chemical properties of the final piece. Moreover, pieces printed by this method, usually, present an incomplete curing process when are extracted from the printer. Since some of the properties of the pieces often depend on this process, in this work Clear02™ resin from Formlabs was used to build samples and the influence of the postcuring process on the final properties of the printed pieces has been evaluated. Two types of postcuring process have been studied over the time: without any source of light and with the exposure to UV light. Both postcuring methods have been proven effective to fully postcured the pieces. In addition, it has been observed that the thermal properties of the material do not depend on how the postcuring process takes place. Nevertheless, a homogenous high crosslinked material with better mechanical properties is obtained with the UV postcuring process. Highlights • Curing process of 3D printing is incomplete and the postcure processes are necessary. • Postcure at room temperature with time and UV light have proved to be efficient and achieve complete cure in 30 hours. • Thermal properties of the material do not depend on the postcure process. • Mechanical properties depend on the curing degree and on the postcuring process used. [ABSTRACT FROM AUTHOR]

Abstract Development of novel environment friendly self-crosslinker, which enables polymers crosslinking without thermal treatment, is highly desirable for several industrial scale applications such as paints and dyes. Herein, we reported a one-pot facile synthesis of hyperbranched polyvinylbenzylchloride (HBPVBC) followed by its quaterinization with pyridine. The resulting product (QHBPVBC) was then used as a crosslinker. Detailed characterization of the HBPVBC and QHBPVBC were conducted by nuclear magnetic resonance (1H NMR), Fourier transform infrared spectroscopy (FTIR) and thermo-gravimetric analysis (TGA). Four different quaterinized crosslinked membranes (QHPs) were prepared by changing the ratio of pyridine to HBPVBC, denoted as QHP-0.25, QHP-0.50, QHP-0.75 and QHP-1.0. Sol-Gel analysis and elemental analysis were used to evaluate the degree of crosslinking and quaterinization of all QHPs. Furthermore, crosslinking effectiveness of QHBPVBC was also demonstrated by introducing QHP-0.50 in sulfonated polyphenyloxide polymer (H+sPPO) structure and observing the mechanical and thermal properties. Initiator-free preparation of QHBPVBC and the self-crosslinking ability in pure aqueous medium at ambient temperature exhibited high effectiveness and environmental-friendly nature. All these outstanding properties facilitated the enhancement of thermal and mechanical properties of linear polymers, making QHBPVBC a potential crosslinker candidate for various industrial applications. Highlights • Initiator-free quaterinized hyperbranched polyvinylbenzylchloride (QHBPVBC) was synthesized successfully. • Structure confirmation was done by 1H-NMR and FTIR analysis. • Effect of Quaterinization on degradation temperature and thermal stability was studied. • Effect of solvent and temperature was studied to see its chemical stability and durability at higher temperature. • Crosslinking effectiveness of QHBPVBC was examined by crosslinking linear structure of H+sPPO. [ABSTRACT FROM AUTHOR]

This work reports the effect of a reactive extrusion (REX) process on polylactide (PLA) based formulations plasticized with dibutyl itaconate (DBI). As DBI contains a carbon-carbon double bond, it is suitable for reactive extrusion. REX was carried out in a co-rotating twin extruder with the addition of two different organic peroxides. The main aim of using REX during the blending of the DBI plasticizer with PLA is to improve the interaction between them so the obtained final properties of the formulations could be improved. Plasticization process allowed to improve the ductile properties of PLA, by using REX, an improvement on the tensile strength was obtained with a no remarkable change in ductility. The thermal characterization also revealed that the glass transition temperature T g was reduced for all formulations including DBI. REX with DBI provided a slight increase in T g and this effect was also evident in thermomechanical properties. Regarding the thermal degradation behaviour, the plasticizer reduced the onset degradation and the maximum degradation rate, while a slight improvement on thermal stability was observed by using REX with organic peroxides. Finally, plasticizer migration in water was observed in conventional extruded PLA/DBI formulations, while REX provided improved behaviour against migration. • Plasticization process allowed to improve the ductile properties of PLA. • Reactive extrusion (REX) improved the tensile strength was obtained with a no remarkable change in ductility. • Thermal degradation behaviour was improved by using REX with organic peroxides. • Plasticizer migration was improved REX provided improved behaviour against migration. [ABSTRACT FROM AUTHOR]

In this paper, hydroxyl terminated polyethersulfone(PES) was used as a toughening agent to modify the monocomponent high performance epoxy resin by blending. The solubility of PES in epoxy resin and the curing performance, mechanical properties, morphology, viscoelastic properties and thermal properties of epoxy/PES blends were investigated, respectively. The dissolution experiment results showed that the hydroxyl terminated PES had a good compatibility with the epoxy resin and could be dissolved in epoxy resin under controlled conditions. FT-IR studies showed that the addition of PES did not affect the result of epoxy resin curing reaction. The results of the mechanical properties of the epoxy/PES blends indicated a 32% and 9% enhancement in fracture toughness and impact strength respectively, which can be ascribed to the bicontinuous phase structure of the epoxy/PES blends. Reaction induced phase separation was observed in the epoxy/PES blends during the curing process of epoxy resin, which presented dispersed particles, bicontinuous and phase inverted structures with the increase of the PES content. Thermogravimetric analysis revealed that the thermal stability of the epoxy/PES blends were slightly increased compared to that of the pure epoxy resin. Thus, the hydroxyl terminated PES could be used to improve the mechanical and thermal properties of the monocomponent high performance epoxy resin. [ABSTRACT FROM AUTHOR]

Natural rubber (NR) composites were reinforced by suitable hybrid fillers system containing short jute fiber and stearic acid modified nano clay. The synergistic effect of short jute fiber and stearic acid modified nanoclay in NR composites was systematically evaluated in the light of cure, mechanical, morphological, dynamic mechanical and thermal properties. Synergistic interaction between short jute fiber and modified nanoclay increased the value of cure rate index (CRI) and tensile strength of NR composites successfully. Scanning electron microscopy (SEM) analysis indicated a continuous and smooth surface for the NR composites containing hybrid fillers system. Dynamic mechanical analysis (DMA) confirmed excellent improvement in the rubber/filler interaction for NR/nanoclay/jute fiber hybrid composites as compared to NR composites with single filler system. Fourier transform infrared (FTIR) study was utilized to explain the transformation of hydrophilic jute fiber surface to more hydrophobic nature in presence of stearic acid modified nanoclay. [ABSTRACT FROM AUTHOR]

ETFE (ethylene tetrafluoroethylene) foils integrated organic photovoltaic cells (OPV) have attracted considerable attention in recent years due to the achievement of sustainability. As building materials, multifunctional OPV-ETFE foils could produce electricity, store thermal energy and possess structural capability. In this case, electrical, thermal and mechanical properties coexist and influence each other due to photovoltaic/thermal effects. Understanding the fundamental mechanism is significant to analyze and design corresponding structures. This paper concerns coupled properties of OPV-ETFE specimens with controlled experiments. One-parameter and two-parameter analysis of two typical specimens are performed to investigate essential properties. Experimental observations show that within normal working conditions, electrical properties are relatively independent but that thermal-mechanical properties are related to each other. Yield stress, yield strain and elastic modulus are calculated from stress-strain curves; these mechanical properties are comparable with those of original ETFE foils at the same temperature. It is concluded from temperature-stress curves that yield point has a critical effect on temperature-stress correlation and that mechanical properties of double OPV specimens are better than those of single OPV specimens. Generally, these mechanical properties could provide basic insights into evaluation of energetic performance and structural behavior of transparent membrane buildings. [ABSTRACT FROM AUTHOR]

Secondary dispersion of the nano barium titanate (BaTiO 3 ) was performed to obtain the fiber-reinforced polyarylene ether nitrile-based (PEN) composite laminates with improved mechanical properties. BaTiO 3 /PEN composite films were prepared via casting with ultrasonic dispersion, and then the glass fiber-reinforced (GF) composite laminates were obtained by the hot-melting method, which were favored to realize the secondary dispersion of the BaTiO 3 nanoparticles. The fracture surface of the BaTiO 3 /PEN films and BaTiO 3 /PEN/GF composite laminates investigated by SEM showed that the BaTiO 3 dispersed homogenously both in the PEN matrix and the gaps between the fibers. The mechanical and thermo-mechanical properties of the laminates were characterized and results indicated that the nano-BaTiO 3 particles and fibers show enhanced synergistic effects. That is, with increasing the BaTiO 3 content, the flexural strength and modulus of the composite laminates increased correspondingly, as well as the glass transition temperatures. Additionally, with the introduction of nano-BaTiO 3 particles, the dielectric constants (>5.5 at 1 kHz) of the composite laminates were improved obviously and the low dielectric loss (˂0.02 at 1 kHz) was maintained. The temperatures at weight loss 5% ( T 5% ) of all the composite laminates with various content of BaTiO 3 were over 490 °C both in N 2 and air atomosphere. Good dielectric properties and outstanding thermo-mechanical properties would enable the PEN-based fiber-reinforced composite laminates as the candidates in the material fields of structure-functional integrations. [ABSTRACT FROM AUTHOR]

Poly(lactide)/halloysite nanotubes (PLA/HNT) nanocomposites with crystalline matrix were obtained by cold crystallization and examined. Neat HNT and HNT treated with N,N′- ethylenebis(stearamide) (EBS) were used as nanofillers. Reference materials, PLA and PLA/EBS blend, prepared in the same way, were also considered. The influence of HNT and/or EBS content on the crystallinity and morphology of PLA matrix, as well as on the dynamic mechanical and optical properties of the materials, was determined. The nanocomposites contained well-distributed HNT, with only occasional agglomerates. HNT, EBS-treated HNT and EBS influenced the morphology of the crystalline PLA matrix and the amounts of the disorder α’ (termed also δ) and order α crystallographic forms of PLA. Crystallinity increased stiffness of the materials compared to their counterparts with the amorphous matrix. Owing to the crystallinity and the presence of the nanofillers, the storage modulus at 20 °C and 60 °C increased by up to 30 and 60%, respectively, compared to neat amorphous PLA. Interestingly, at lower nanofiller content the crystalline nanocomposites with EBS were more transparent than neat crystalline PLA. [ABSTRACT FROM AUTHOR]

Thermal and mechanical properties of polylactide (PLA) composites with different grades of calcium carbonate, 40 nm and 90 nm nanoparticles, and also with submicron particles, unmodified and modified with calcium stearate or stearic acid, obtained by melt mixing, were compared. Films with amorphous and crystalline matrices were prepared and examined. T g of PLA in the composites remained unaffected whereas its cold crystallization was enhanced by the fillers and predominantly depended on filler content. Filling decreased thermal stability of the materials but their 5% weight loss temperatures well exceeded 250 °C, evidencing stability in the temperature range of PLA processing. The amorphous nanocomposites with modified nanoparticles exhibited improved drawability and toughness without a significant decrease of tensile strength; nearly two-fold increase of the elongation at break and tensile toughness was achieved at 5 wt% content of the modified nanofiller. Lack of surface modification of the filler, larger grain size with an average of 0.9 μm, and matrix crystallinity had a detrimental effect on the drawability. However, the presence of nanofillers and crystallinity improved tensile modulus of the materials by up to 15% compared to neat amorphous PLA. [ABSTRACT FROM AUTHOR]

Electrospun nanofibers have been widely researched for their reinforcing ability in polymer composites because of their ultrafine size, high mechanical strength, and ultrahigh surface area. In this study, a vacuum infiltration technique was employed to fabricate electrospun nylon 6 nanofiber-reinforced epoxy matrix composites. It was found that the reinforcement of the epoxy matrices with nylon 6 nanofibers significantly improved the mechanical and thermal properties of the composites. The ultimate tensile strength of the N6/YD composite decreased compared to that of the reference YD epoxy resin; however, the N6/YDJR and N6/JR epoxy resin composites showed 29% and 500% improvement in the tensile strength, and Young's modulus was enhanced by 20.5%, 49%, and 1700% for the N6/YD, N6/YDJR, and N6/JR composites, respectively. Furthermore, the tensile strength and Young's modulus of the nanocomposites were predicted and validated using the theoretical Halpin–Tsai and Takayangi models, while the results of numerical simulations agreed with the experimental measurements. Finally, a thermogravimetric analysis showed that the thermal stability of the epoxy resin matrices was significantly improved after the incorporation of nylon 6 nanofibers. • Transparent electrospun nylon 6 nanofiber-reinforced epoxy matrix composites were prepared. • The prepared composite showed improvement in mechanical, thermal, and optical properties. • The mechanical properties of the prepared composites were validated using conventional and modified analytical models. • Numerical models were applied for the randomly dispersed continuous polymer nanofiber-reinforced epoxy matrix composites. [ABSTRACT FROM AUTHOR]

Dispersion of platelet-like nanominerals in low-viscous resins is a serious challenge; which arises from the strong interactions among the large surface area of the layers. Herein, we improved the dispersion of graphene oxide (GO) within unsaturated polyester (UP) resin and synergistically enhanced the mechanical and thermal properties of the resulting nanocomposites. In a multi-stage manner, GO was incorporated into a novel hybrid structure before adding to the polymer matrix alongside with benefited from the advantage of surface functionalization. Functional hybrid nanofiller skeletons comprising GO and nanoclay (NC) were designed and prepared at different composition ratios (25:75, 50:50 and 75:25) and different surface chemistries via modification with two thermal-resistant silane coupling agents, namely (3-Aminopropyl) triethoxysilane (APTES) and 3-(trimethoxysilyl) propyl methacrylate (MPS). The optimal loading of different hybrid structures into UP has been examined by applying three loading levels (0.25, 0.50 and 1.00 wt%). The results indicated the synergistic effects of GO and NC on the mechanical properties of UP, where the composition ratio of the hybrid constituents played a key role. Moreover, it was demonstrated that the range of composition ratio for the realization of synergistic reinforcement is strongly affected by the surface chemistry of the GO and NC. For UP matrix reinforced with APTES-modified hybrid nanofillers of GD:CD at 50:50 w/w composition, a higher tensile modulus compared to blank UP (≈+21.5%) was obtained due to boosted dispersion of nanoplatelets in UP matrix. The results of DMTA and TGA analyses suggested that there are two different UP/GO and UP/NC interfacial interactions in the composites containing unmodified hybrid nanofillers. However, after modification of hybrid nanofillers, the homogeneous dispersion of nanoplatelets boosted the interfacial interactions between nanofillers and polymer, such that higher properties were obtained. • Visualized the role of surface chemistry on dispersion of graphene oxide (GO) and nanoclay (NC) in unsaturated polyester (UP). • Effect of surface functionalization on the thermomechanical behavior of GO/NC/UP nanocomposites. • Functionalization of hybrid UP nanocomposites by silane coupling agents, APTES and MPS. • Synergistically enhanced mechanical and thermal properties of resulting nanocomposites. [ABSTRACT FROM AUTHOR]

Amorphous polylactide/halloysite nanotube (PLA/HNT) nanocomposites were prepared and examined. Neat HNT and HNT treated with N,N' - ethylenebis(stearamide) (EBS) were used as nanofillers. The role of HNT and/or EBS content on the cold crystallization of amorphous PLA matrix, HNT dispersion, as well as on the dynamic mechanical and optical properties of the materials was determined. The PLA/HNT-based nanocomposites contained well-distributed nanotubes and occasionally micron-sized aggregates, especially at high loading. HNT, EBS treated HNT and EBS influenced the cold crystallization of PLA, therefore the formation of the disorder α′ and the order α crystallographic forms of PLA. The nanocomposites exhibited increased stiffness and decreased transparency compared to the neat PLA. Due to the reinforcing effect and additional specific features of HNT, the addition of the nanofiller allows tuning of the properties of the nanocomposites with amorphous PLA matrix. [ABSTRACT FROM AUTHOR]

A polymer plasticization rate measurement method is proposed for ultrasonic plasticization microinjection molding. The effect of ultrasonic amplitude on the plasticization rate of polypropylene (PP) rods was comprehensively investigated, and the mechanical and thermal properties of PP rods were studied using tensile tests, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Results show that the plasticization rate of PP rods increased from 67.25 mg/s to 192.41 mg/s with increase of ultrasonic amplitude, an increase of 186%. The mechanical properties of the PP samples remained stable under different ultrasonic amplitudes, with tensile strength around 21 MPa and elongation at break about 21%. DSC and TGA results showed that PP samples exhibit improved thermal properties after ultrasonic plasticization compared with pure PP. The melting point of the PP sample decreased from 171.7 °C to 164.0 °C and the crystallinity increased from 26.1% to 38.7%. The temperatures corresponding to 1% and 5% weight loss of PP increased from 283.63 °C to 350.30 °C without ultrasonic amplitude to 393.70 °C and 420.13 °C, respectively. The studies have great significance to further understand the influence of ultrasonic plasticization process parameters on the plasticization rate and material properties of polymers. • A simple real-time method for measuring polymer plasticization rate is presented. • The plasticization rate can be significantly increased with increasing ultrasonic amplitude. • The properties of the parts is not undermined while the molding process is more efficient with increasing ultrasonic amplitude. [ABSTRACT FROM AUTHOR]

This study aims at quantifying the nano-size effect in terms of elastic and thermal properties in nano-reinforced polymers. Nano-reinforced PMMA with 4% volume fraction of silica nanoparticles was prepared using particle diameters of 15 nm, 25 nm, 60 nm, 150 nm and 500 nm. Uniaxial tensile tests showed an increase in Young's modulus with decreasing particle diameter when the volume fraction was kept constant. This increase is the signature of the nano-size effect on the macroscopic mechanical properties. Conversely to mechanical properties, the presence of particles in the matrix induced a decrease in glass transition, possibly due to weak interactions between the matrix and silica nanoparticles. [ABSTRACT FROM AUTHOR]

Nitrile-butadiene rubber (NBR) was exposed to an accelerated thermal aging environment produced by an air-circulating oven for different time periods. NBR aging was evaluated by morphology, crosslink density, mechanical properties, chemical changes and thermal stability. The results showed that the surface damage of NBR turned severe and inhomogeneous, and the aging degree was most serious on the edge region of voids. Crosslinking reactions mainly occurred in the aging process. The tensile strength increased with increase in crosslink density up to a maximum value and thereafter decreased with further increase in crosslink density. X-ray Photoelectron Spectroscopy (XPS) and Pyrolysis Gas Chromatography-Mass Spectrometry (Py-GC/MS) analysis demonstrated that hydroxyl groups were formed and the additives migrated from inner to surface of NBR samples. In addition, the thermogravimetric analysis (TGA) indicated that the thermal stability of NBR did not significantly change in the accelerated thermal aging environment. [ABSTRACT FROM AUTHOR]

This study gives an overview of the most relevant processing and performance properties of a wide selection of biobased and biodegradable plastic materials that are currently commercially available. It provides the most extensive and up-to-date scientific overview of critical properties of biobased and biodegradable plastics. Materials that are tested include fully biobased polymers (polylactic acid, polyethylene, polyamide 10,10 and a range of polyhydroxy alkanoates), partially biobased polymers (polybutylene succinate, polybutylene succinate adipate, cellulose acetate, cellulose acetate propionate, polyethylene terephthalate, polytrimethylene terephthalate, an isosorbide based polycarbonate, a thermoplastic urethane and a starch based blend) and a number of fossil-based materials (polycaprolactone, polybutylene adipate terephthalate, polyglycolic acid and polypropylene). The mechanical (tensile, flexural, impact resistance and hardness), thermal (glass transition temperature, melting temperature, melt-flow index and haul-off force) and barrier (oxygen transmission rate, water vapour transmission rate) properties of all these materials were measured and are presented in a comprehensive overview. This overview shows that the majority of functionalities that are currently being offered by fossil based polymers can be met by biobased alternatives and by biodegradable materials if this is considered to be favourable at end-of-life. • The most extensive and up-to-date scientific overview of critical properties of biobased and/or biodegradable plastics. • Mechanical properties characterized; tensile, flexural, impact resistance and hardness. • Thermal properties characterized; glass transition temperature, melting temperature, melt-flow index and haul-off force. • Barrier properties characterized; oxygen transmission rate, water vapour transmission rate. [ABSTRACT FROM AUTHOR]

Herein, we enhanced the epoxy resin's mechanical, thermal, and radiation shielding properties by introducing graphitic heavy oil fly ash (HOFA) to produce composite sheets at various weight fractions of HOFA, namely, 0, 10, 20, and 30 wt%. The morphology, chemical group functions, mechanical properties, thermal properties, and the X-ray and neutron shielding properties of the produced epoxy resin/HOFA composite sheets were rigorously tested. The SEM images showed a uniform distribution for the HOFA particles in the polymer matrix. The FTIR spectra revealed a new peak of C=C bounds, suggesting that the epoxy resin/HOFA composites were tightly bounded through these functional sites. The mechanical results showed that Young's modulus and stiffness were enhanced gradually by increasing the HOFA weight fraction; for instance, Young's modulus increased by ∼20% compared with neat epoxy. The hardness obtained by the nanoindentation test was also significantly enhanced by around 25% by increasing the HOFA weight fraction. The observed micro scratch confirmed these mechanical enhancements. The thermal conductivity and diffusivity were slightly increased by increasing the load of HOFA, but this was combined with an apparent increase in the value of the char yields, suggesting improvements in the thermal properties. The X-ray shielding results showed increases in the linear attenuation coefficients and decreases in the half-value layer, indicating better shielding properties; no effects were detected in the neutron shielding while HOFA addition. These results clearly demonstrated the possibility of reinforcing the epoxy resin thermal, mechanical, and radiation shielding properties using the waste HOFA material to be a valuable and economical material used in polymer composite applications, such as constructions, piping, and automobiles. • Heavy oil fly ash (HOFA) was used to enhance epoxy resin composition. • The HOFA epoxy resin composition enhanced the mechanical and the thermal properties of the material. • The HOFA epoxy resin composition can be used as a radiation shielding material for photons. [ABSTRACT FROM AUTHOR]

Simultaneously enhancing the thermal conductivity, insulation, and mechanical properties of high-density polyethylene (HDPE) composites is highly desired for electronic and electrical applications. In this research, HDPE/boron nitride (BN)/coconut shell charcoal (CSC) composites were prepared. Benefit from the synergistic effect between the multi-dimensional hybrid fillers, the prepared HDPE/BN/CSC composites exhibited enhanced comprehensive properties compared to the HDPE/BN composites and pure HDPE. In particular, as for HDPE/25BN/3CSC (25 wt% BN, 3 wt% CSC) nanocomposites compared to the pure HDPE, enhancements in in-plane thermal conductivity of 980.89%, normal thermal conductivity of 138%, and tensile strength of 18.91% were obtained, while higher volume resistivity and decomposition temperature were achieved. This work provides a simple but effective way for improving the thermal conductivity and comprehensive physical properties of HDPE composites. • HDPE/BN/CSC composites were prepared. • High thermal conductivity of the HDPE/BN/CSC composites were achieved. • Thermal stability, mechanical properties, and insulation properties were all enhanced at appropriate CSC contents. [ABSTRACT FROM AUTHOR]

This paper presents a comparative study of the use of polyethylene grafted maleic anhydride (PE- g -MAH) and glut palmitate salt (GP) as compatibilizers in silica-filled high-density polyethylene (HDPE) composites. The composites with varied compatibilizer loadings [0.5–3.0 phr] were prepared by melt mixing, followed by compression moulding. The interaction of compatibilizers in the composite system was investigated using Fourier transform infra-red (FTIR), while tensile and impact tests were performed to evaluate the mechanical properties of the composites. The thermal properties were also determined. Mechanical studies indicated that composite prepared at 1 phr GP exhibited higher tensile strength, elongation at break and impact strength than PE-g-MAH composites under the same loading. Degree of crystallinity (Xc) calculated from differential scanning calorimetry (DSC), and thermal stability investigated using thermogravimetric analysis (TGA) revealed that composites with GP had higher Xc and thermal stability values than composites with PE-g-MAH. In addition, the water absorption of GP compatibilized composite was lower than that for the PE-g-MAH. [ABSTRACT FROM AUTHOR]

A series of novel polyethyleneimine (PEI) modified graphene oxide (PEI-mGO) filled poly(vinyl alcohol) (PVA) nanocomposite (PEI-mGO/PVA) films were prepared by solution-casing for hydrogen gas barrier applications. Hydrophilic PEI was used to simultaneously reduce and modify graphene oxide sheets, thereby facilitating a homogeneous dispersion of PEI-mGO in the PVA matrix. The effects of PEI-mGO on the morphology and properties of the nanocomposite films were examined by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis and field emission scanning electron microscopy. Analogous GO/PVA composites were also prepared and characterized for comparative purposes. The PEI-mGO/PVA nanocomposites showed higher thermal and mechanical stability as well as remarkable improvement in hydrogen gas barrier properties compared to the PVA film; specifically, the PEI-mGO/PVA film having 3.0 wt% of PEI-mGO content exhibited almost 95% decrease in GTR and permeability values compared to PVA film. [ABSTRACT FROM AUTHOR]

Polylactide (PLA) is an attractive and widely used polymer which has received much attention in the last decade since it is biodegradable and produced from renewable resources. The polymer is of interest in the production of packaging films. However, plasticization of PLA is required in order to obtain soft films. In this work, PLA was blended with a new renewable oligomer obtained from biodiesel. The crystallization behavior and the mechanical properties of the blends were investigated for contents up to 20wt% of plasticizer. The plasticizing effect was characterized by a decrease on the glass transition temperature due to an increase in PLA chain mobility, which induced crystallization on heating. Thermal stability was not significantly affected, and mechanical properties showed an increase in ductility with the plasticizer content. Good compatibility was observed between the plasticizer and PLA, making this material suitable for biodegradable film manufacture. The addition of the plasticizer did not induce Tg increase with aging. However, a significant increment of crystallinity was observed after one year of storage at room temperature for the blend containing 20% of the plasticizer. [ABSTRACT FROM AUTHOR]

Ethylene-vinyl acetate (EVA)/sepiolite nanocomposites were prepared by melt blending in a twin screw extruder. The structural, morphological, thermal, flammability and mechanical properties of the EVA/sepiolite nanocomposites were investigated using X-ray diffraction (XRD), Fourier transform infrared (FTIR), field emission scanning electron microscopy (FESEM), thermal analysis, tensile properties and limiting oxygen index (LOI) measurements. X-ray diffraction analysis and FESEM revealed good dispersion of sepiolite in EVA matrix. The tensile strength of EVA/sepiolite increased by 21% and Young's modulus increased by 47% at 5 wt% and 7 wt% sepiolite content, respectively. The thermal stability and fire retardancy of the nanocomposites improved with sepiolite incorporation. [ABSTRACT FROM AUTHOR]

Abstract: Effects of nanofiller concentration and surface treatment on the morphology, thermal, viscoelastic and mechanical behavior of polypropylene copolymer (PP)/boehmite alumina (BA) nanocomposites were investigated. Both untreated BA particles and those treated with octylsilane (OS) or sulphonic acid compound (OS2) were added at up to 10 wt% to produce nanocomposites by melt mixing followed by film blow molding and hot pressing. Dispersion of BA was studied by scanning electron microscopy. Differential scanning calorimetry and wide-angle X-ray scattering were adopted to detect changes in the crystalline structure of PP. Thermooxidative degradation of the nanocomposites was assessed by thermogravimetrical analysis. Dynamic mechanical analysis served for studying the viscoelastic properties, whereas quasi-static tensile, creep and Elmendorf tear tests were used to detect changes in the mechanical performance. BA nanoparticles were finely dispersed in PP up to 10 wt%, even when they were not surface modified. The resistance to thermal degradation was markedly improved by BA nanomodification. Since the crystalline characteristics of the PP matrix did not practically change with BA modification, changes observed in the mechanical properties were attributed to BA dispersion, filler/matrix interactions and related effects. [Copyright &y& Elsevier]

Abstract: Nanocomposites composed of cellulose nanofiber (CNF) and polylactic acid (PLA) were prepared using a solvent casting method, with the goal of making green nanocomposites. Prior to the incorporation of CNF into the polymer matrix, surface modification of CNF was accompanied by esterification to improve the dispersion of CNF and its interfacial adhesion with the biopolymer. Microstructure, barrier, mechanical and thermal properties of the nanocomposites were studied. Scanning electron microscopy (SEM) micrographs revealed uniform distribution of nanoparticles in the polymer matrix at low contents (1 and 3 wt%), but also that a higher content (5 wt%) of CNF was easily agglomerated. This caused the mechanical properties of the nanocomposites to be reduced. The results of water vapor permeability (WVP) tests showed that the use of acetylated nanofibers had no significant effect on the permeability of films. Tensile strength (TS) and elastic modulus (EM) of nanocomposites with 1 wt% CNF did not show significant changes, however elongation percentage (E) increased by more than 60%. The TS, EM and E changed significantly for nanocomposites with 3 and 5 wt% CNF. Moreover, nanofiber orientation effectively occurred in the PLA matrix. The reinforcing effect of CNF composition with PLA caused a slight increase in glass transition and melting temperatures. However, the nanocomposite films showed a very similar pattern of thermal behavior to that of neat PLA film. [Copyright &y& Elsevier]

Abstract: This paper reports on the effects of lignin, polyvinyl pyrrolidone and polyethylene glycol as additives to polysulfone ultrafiltration membranes prepared by nonsolvent induced phase separation. The focus is on the mechanical and thermal properties of the resultant membranes. Differential scanning calorimetry (DSC) and thermogravimetric analysis were used to probe the thermal properties, while an Instron tensile tester was used to characterise the mechanical properties. Morphological studies indicate that the porosity of the bottom sub-layer increased with the use of each additive, suggesting that coagulation in the sub-layer differed from that of the top layer. Membranes fabricated using lignin were thermally stable as the residue at 800 °C increased from 13% to 44%, suggesting interaction of lignin with the polymer. The increase in free fractional volume was confirmed by DSC thermograms as the glass transition temperature decreased considerably after incorporating the additives. Generally, the modulus and tensile strength decreased after the introduction of the additives. These results offer new insight into the use of an emerging, cheap and readily available natural additive (lignin) compared to traditional synthetic additives in membrane formation. [Copyright &y& Elsevier]

Abstract: This work focuses on the development of gel-like formulations for use as lubricating greases. These dispersions were formulated using mineral oil and recycled/amorphous polypropylene blends. In particular, the influence of the polypropylene concentration ratio (Wi) on the rheology, thermal and some lubricant performance properties of polymer/oil blends were studied. The rheological responses of these systems were quite different, influenced mainly by the concentration of amorphous polypropylene. At intermediate temperatures (25 °C, 50 °C) and high recycled polypropylene concentrations (Wi > 0.5), the evolution of small-amplitude oscillatory shear (SAOS) functions was very similar to those found with other commercial lubricating greases. Samples with lower concentrations of amorphous polypropylene (12.5%) present maximum values in the temperature range studied. An Arrhenius-type equation can be used to quantify the thermal dependence of the linear viscoelastic functions of these gel-like dispersions. In general, sample formulations studied exhibited values of the friction coefficient comparable to those found for traditional lithium lubricating greases. [Copyright &y& Elsevier]

Abstract: Polyamide 46 (PA 46)/graphene oxide (GnO) nanocomposites were successfully prepared using a solution mixing technique. GnO was obtained by modifying pristine graphite through oxidation treatment along with ultrasonication in formic acid. Raman spectroscopy showed a high intensity ratio of D to G bands (I D /I G  = 0.96) for the oxygen-functionalized graphite, confirming efficient modification of pristine graphite. Transmission electron microscopy demonstrated nanoscale dispersion of GnO within the PA 46 matrix. Polarized light microscope observations showed that the inclusion of GnO led to the formation of small PA 46 crystallites rather than large crystalline spherulites of neat PA 46. Differential scanning calorimetry results indicated that adding a small amount (i.e., 0.25 wt.%) of GnO noticeably aided the nucleation of PA 46, which corresponded to the morphological observations. The presence of GnO also induced PA 46 crystals with higher stability, thus reducing the possibility of crystal annealing during the heating scans. The melting temperature of PA 46 in the nanocomposites increased to higher temperatures. As confirmed through in-situ x-ray diffraction experiments, the Brill transition of PA 46 crystals shifted from approximately 160 °C to 180 °C with the inclusion of GnO. Dynamic mechanical analysis demonstrated the rigidity (storage modulus) enhancement of PA 46 after GnO additions. [Copyright &y& Elsevier]

Abstract: In this experiment, various types of carbon black (CB) were employed to partially substitute the calcined clay for preparing natural rubber (NR) compounds of similar hardness. At similar hardness, the compounds containing both clay and CB give the better tensile strength, edge-cut tensile strength, tear strength and thermal ageing resistance compared to the control, but the control had better gas barrier property. In addition, the cracking behaviour of the vulcanizate has a transition from simple lateral growth to oblique crack with partial substitution of the clay with CB, and the vulcanizate containing N330 exhibits the greatest longitudinal cracking corresponding to its highest edge-cut tensile strength. This means the presence of N330 causes the greater orientation of the NR chains along the applied force. Furthermore, the vulcanizate containing N330 yields the highest tensile and tear strength, and lowest resilience, although it has the lowest volume fraction of filler. The explanation is given as the higher reinforcing efficiency of N330 and the better filler dispersion shown in SEM micrographs. [Copyright &y& Elsevier]

Abstract: Poly(trimethylene terephthalate) (PTT) and a liquid crystalline polymer, Vectra A950 (VA), were melt-blended and subjected to capillary rheometry. Effects of VA content, shear rate and temperature on viscosity and flow activation energy (E a) were investigated. Partial fibrillation was found even though the viscosity ratio was greater than one, leading to the formation of in-situ composites. Thermal and thermogravimetric analysis of the blends suggested that they were immiscible and their thermal stabilities were enhanced. From tensile tests, the incorporation of VA improved tensile modulus, slightly decreased tensile strength, and drastically lowered elongation at break, compared to neat PTT. It was found that the blend with the best VA dispersion can be achieved at the minimum VA content (10wt%) and lowest processing temperature (250°C). Not only did this blend exhibit improved mechanical properties comparable to those of blends processed at temperatures closer to the crystalline-to-nematic transition of VA (∼280°C), it also shows enhanced processibility through the reduction of both melt viscosity and E a. [Copyright &y& Elsevier]

Abstract: A series of novel thermoplastic block copolymers (BCPs) based on an aliphatic copolyamide and an oligodiene having isocyanate end groups were prepared to obtain new thermoplastics with improved properties. The structure of the new block copolymers was controlled by the molar ratio of components and monitored by the means of IR and 1H NMR spectroscopy. The morphology of the BCPs was investigated using electronic microscopy (SEM), thermal behaviour was evaluated by differential scanning calorimetry (DSC) and mechanical properties were studied by specific tests. Starting from these BCPs and using polyethylene waste (secondary polyethylene s-PE), new polymeric blends were obtained and subsequently characterized. A morphology study was performed and mechanical characteristics of these blends comparatively evaluated. We concluded that the new block copolymers can be successfully used as a component of such blends for the recovery of polymeric waste, a viable alternate solution for waste management. [Copyright &y& Elsevier]

Abstract: The effects of repetitive extrusion cycles at different die temperatures in a single screw extruder were investigated by thermal analysis (degree of crystallinity (χ c), heat of fusion (ΔH m), melting temperature (T m) and the onset melting temperature (T onset,m)) and mechanical properties (tensile and impact strength). Also, analysis of variance (ANOVA) and response surface methodology (RSM) were employed for modeling and analysis of the mechanical property results. Thermal analysis verified an increase for χ c and ΔH m with a continuous reduction in the T m and T onset,m values with increase of die temperature and/or cycles of extrusion. For mechanical properties, the observed degradation process only slightly affects the small strain properties (yield stress and modulus) and impact strength. Break properties (break stress, break strain and energy to break) were reduced significantly by the experimental conditions adopted. According to ANOVA and RSM, the degradation process was occasioned more by high shear rate (repetitive number of cycles) than by high processing temperatures. [Copyright &y& Elsevier]

Abstract: The suitability of using polypropylene modified with an organosilane as a coupling agent for polypropylene/wood-flour composites was investigated. The tensile properties, the water-absorption behavior, the thermal degradation properties and the morphology of the composites were analyzed and compared with those of non-coupled composites and of composites coupled with polypropylene modified with maleic anhydride. The coupling agents were prepared in the laboratory and it was verified that the silane showed higher reactivity towards PP chains. The results indicated that the silane-modified polymer increased the interfacial adhesion between the fibers and the polymer matrix and this effect was better than that obtained for the maleated-polypropylene-coupled composites. [Copyright &y& Elsevier]

Abstract: Oxidized paraffin wax was used as a possible compatibilizer in composites containing LLDPE and layered nano silicate clays. The samples were analysed using X-ray diffraction (XRD), tensile analysis, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). There was no exfoliation or intercalation of the clay layers in the absence of wax, while an obvious increase in d-spacings was observed when the samples were prepared with wax present. Generally, the modulus increased with both clay and wax contents, while the tensile strength generally decreased. The type of modifier in the clay determined the extent of the changes in these properties. The thermal stability of linear low-density polyethylene (LLDPE) generally improved with increasing clay content, but the presence of wax seems to slightly reduce the thermal stability, although these samples were still more thermally stable than pure LLDPE. Both clay and wax had an obvious influence on the crystallization behaviour of LLDPE, which was also determined by the type of modifier in the clay. [Copyright &y& Elsevier]

Flexible polyurethane foams (FPUs) having polystyrene (PS) stabilized by silica gel or polystyrene-acrylonitrile (SAN) particles were synthesized employing polymer polyether polyols (PPPs). The filler and its content effect on physical, mechanical and thermal properties of FPUs were studied. The FPU thermal stability increased with PS content into PPP and no interaction filler-polymeric network was observed. Meanwhile, FPUs containing PS as filler were more thermally stable and mechanically resistant -except the elongation-than those from the commercial PPP containing SAN. Contrary to porosity and cell size, the density and hardness are function of the filler type and increase with the filler content although the hardness is practically constant from 10 wt%. Closed cell foams instead of tight foams were produced from filler contents higher than 15 wt%. Synthesized FPUs presented better hardness and density properties but worse mechanical properties than the commercial one. Finally, mechanical properties were similar than FPUs containing inorganic fillers. •Foams containing PPPs stabilized by silica gel were successfully synthesized. • The PPP with the smallest PS particles originated smaller and more homogeneous cell size. •PPP-PU showed higher thermal stability and hardness keeping the rest of properties •The maximum density value obtained was 41 kg/m3 employing 40 pph of PPP 43. •The PPP-PU foams satisfied the requirements to be applied in the automotive sector. [ABSTRACT FROM AUTHOR]

The aim of this work is to investigate the performance variability of post-industrial (PIR) and post-consumer recycled (PCR) polycarbonate acrylonitrile-butadiene-styrene (PC-ABS). In addition, necessary testing methodology for understanding polymer variation in recycled polymers are established. The thermal expansion behaviour of all tested material were found to be similar and FT-IR testing revealed no conclusive evidence of oxidative degradation. Both PIR and PCR exhibited similar levels of variation in mechanical properties compared with prime samples, with the exception of elongation at break and quasi-static impact behaviour. In these two tests, prime polymers showed lower variation and superior performance to both recycled polymers. The presence of defects and changes in molecular weight were determined to be leading causes of the reduced deformability. Our work contributes by identifying key areas where recycled PC-ABS show good potential as replacements for neat PC-ABS. Furthermore, the work demonstrates methods for material testing against performance criteria to pave way for effective replacement of neat PC-ABS with its recycled counterparts. [Display omitted] • Commercially available recycled PC-ABS performances were compared with neat PC-ABS. • Different methodologies for comparison of polymer recycled alternatives were analyzed. • Statistical analysis was used to quantify levels of variation. • Recycled PC-ABS showed similar variation to the neat except in toughness measurements. • Defects and changes in molecular weight determined to have caused lower toughness in recycled PC-ABS. [ABSTRACT FROM AUTHOR]

Poly (arylene ether nitrile) (PEN) is a kind of high-performance engineering plastic and their properties can be tuned by the copolymerization of various structural diphenols and dichloro (fluoro)-benzonitrile. In this work, a series of phenolphthalein and bisphenol AF based PEN (PP/BPAF-PEN) copolymers were designed and synthesized. Structures, molar weights, mechanical and thermal properties were studied. Results showed that PP/BPAF-PEN copolymers were successfully synthesized and exhibited good compatibility, outstanding thermal and mechanical properties. Besides, PP/BPAF-PEN exhibited excellent T g up to 260 °C (DSC), tensile strength of 120 MPa, high T d5% and char yields (>70%). With incorporation of –CF 3 into molecular chains, dielectric constant of PP-PEN (3.41 at 1 MHz) was decreased to 3.05 of PP/BPAF-PEN and dielectric loss was around 0.01. Hence, the obtained PP/BPAF-PEN copolymers possessing excellent properties could be applied as the candidates in flexible printed circuit (FPC) substrate. • PP/BPAF-PEN copolymers were synthesized and results showed that the copolymers exhibited well compatibility. • PP-PEN possessed excellent T g (260 °C) and mechanical properties (tensile strength > 120 MPa, tensile modulus > 3434.6 MPa). • PP/BPAF-PEN gained dielectric constant of 3.05 at 1 MHz and all of PP/BPAF-PENs exhibited T g > 200 °C (by DSC). • Thermal stability was enhanced with incorporation of BPAF into molecular chains. [ABSTRACT FROM AUTHOR]

This is the first investigation aimed to enhance the mechanical, thermal and viscoelastic properties of epoxy based sisal composites using eco-friendly treatment (i.e. NaHCO 3 treatment) followed by eco-friendly polymer coating (i.e. PLA coating). The composites were fabricated by manual method with a constant content and length of fibres as 16 wt% and 15 mm, respectively. Mechanical tests on the prepared samples were performed in terms of tensile, flexural, impact and hardness. The thermal stability of the prepared composites was also measured by TGA analysis, whereas viscoelastic properties were measured by dynamic mechanical analysis. Moreover, morphological analysis of tested samples was also carried out by SEM. Tensile and flexural performances of treated and coated composites were found to be greater than those of untreated and treated sisal composites, whereas impact strength was found to be reduced. The treated and coated composite SC(T2) has 34.80% and 27.46% more values of tensile strength, and has 19.69% and 8.54% more values of tensile modulus as compared to those of untreated composite SC and treated composite SC(T1), respectively. There was a nominal improvement of 6.76% and 1.33% in the hardness of composite SC(T2) than those of composites SC and SC(T1), respectively. Thermal stability, storage modulus and glass transition temperature were also considerably improved owing to treatment followed by coating of the fibres. • To overcome the limitations of biocomposites. • Improvement in mechanical performances of sisal composites using a novel approach of treatment. • Improvement in dynamic mechanical properties by eco-friendly treatment and coating. • Improvement in thermal properties by eco-friendly treatment and coating. • To make the biocomposites suitable for sustainable applications. [ABSTRACT FROM AUTHOR]

In this study, three different electrostatic powder coating wastes of thermoset structure were used as fillers for low-density polyethylene (LDPE). The mechanical, thermal, and morphological properties of these composites materials are reported. The thermoset powder coating wastes were hydrolyzed using water and alcohol, and then 10%, 20%, and 30% by weight of the deactivated wastes were mixed with LDPE, first in a mechanical dry mixer, and subsequently homogenized by melt compounding in an extruder at about 160 °C. Standard tensile test bars and plate-shaped samples were produced from these homogeneous compounds by injection molding. The effects of adding hydrolyzed powder coating wastes on the properties of LDPE were determined by mechanical, thermal, and morphological tests. Tensile strength and perforation threshold of the sample filled with powder coating wastes decreased to some extent compared to un-filled sample. However, an increase in izod impact and bending strengths has been observed. The results of this investigation demonstrate that powder coating wastes with thermoset structure can be used as fillers in LDPE. • Three different electrostatic powder coating wastes of thermoset structure were used as fillers for low-density polyethylene. • Hydrolyzed powder coating belonging to thermoset systems of epoxy, hybrid, PU coating materials were used as fillers. • Tensile strength of the samples with increasing filler amount decreased but improvements in bending strength were observed. • The samples filled with epoxy-based filler absorbed about 60% less energy in low-velocity impact tests. • The irregular distribution of the filler on the matrix surface indicate that homogeneity is not sufficiently achieved. [ABSTRACT FROM AUTHOR]

This work aims at producing and characterizing unidirectional carbon/epoxy composites containing different fractions of paraffin microcapsules (MC) for thermal management applications. The viscosity of the epoxy/MC mixtures increases with the MC content, thereby increasing the final matrix weight and volume fraction and reducing that of the fibers. This is at the basis of the decrease in mechanical properties of the laminates with high MC concentration (the elastic modulus decreases up to 53% and the flexural strength up to 67%), but the application of theoretical models shows that this decrease is only due to the lower fiber volume fraction, and not to a change in the properties of the constituents or the fiber/matrix interaction. The MC phase is preferentially distributed in the interlaminar zone, which leads to a thickening of this region and a decrease in matrix-related properties, such as the interlaminar shear strength, which decreases of up to 70%. However, a modest MC fraction causes an increase in the mode I interlaminar fracture toughness of 48%, due to the introduction of new toughening mechanisms. On the other hand, an excessive MC content lets the crack propagating through the matrix and not at the fiber/matrix interface, thereby reducing the toughening mechanism provided by fiber bridging. For the thermal properties, the phase change enthalpy increases with the MC fraction up to 48.7 J/g, and this is reflected in better thermal management performance, as proven by thermal imaging tests. These results are promising for the development of multifunctional polymer composites with thermal energy storage and thermal management properties, and future works will be focused on a deeper study of the micromechanical properties of PCM microcapsules and on the improvement of the capsule/matrix adhesion. Image 1 • Multifunctional carbon/epoxy composites containing paraffin core-shell microcapsules. • Mild production process preserves the integrity of microcapsules. • High phase change enthalpy, up to 48.7 J/g. • Fracture toughness increases as new toughening mechanisms add up to fiber bridging. • Viscoelastic parameters are affected by paraffin melting and crystallization. [ABSTRACT FROM AUTHOR]

In the present decade, the demands for recyclable, environmentally friendly and low-cost with good strength composites materials have been significantly increased. In this context, the particulate wood polymer composites have attracted the researchers owing to their eco-friendliness, low-cost as they are prepared using waste wood particles, and good mechanical and physical properties. These composites were prepared by filling the waste wood particles into the polymers using different fabrication methods such as extrusion, hand layup, compression moulding, injection moulding and additive manufacturing (3D printing). A good number of research works have been reported on the testing and characterization of wood composites for the various applications so far. This fact motivated to prepare a state-of-the-art review on the recent developments in processing, characterization, and applications of wood composites. This paper presents a discussion on the chemical structure and properties of different types of wood species. The mechanical, thermal and water absorption behaviour of thermosets, thermoplastics and biopolymers based wood composites have also been discussed. Further, characterization of the nano biocomposites prepared using nanocellulose/nanoparticles of wood are also presented. The outcomes of the present review provide a good understanding of wood composites that will encourage the researchers for further research works & developments of novel wood composites for the advanced applications. • Wood composites are environmental friendly and low cost materials. • Study on fabrication methods of wood composites. • Characterization of wood composites. • Characterization of chemically treated wood composites. • Recent applications of wood composites. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the reinforcing effect of Ceratonia siliqua (CS) powder as a novel natural filler for polypropylene (PP) based composites. CS powder up to 20 wt% was filled into PP matrix by using high speed thermo kinetic mixer. Mechanical and thermal properties of CS filled PP based composites were investigated by tensile and three point bending test, dynamic mechanical analysis, thermogravimetric analysis, differential scanning calorimetry analysis, fourier transform infrared analysis, and thermomechanical analysis. Morphology of the composites was also investigated by scanning electron microscopy. By filling 5% and 10% of CS into PP, tensile strength and flexural strength of PP increased by about 32 and 23%, respectively. This indicates that CS has a great potential to be used as reinforcing filler for PP composites. CS filling into PP led to lower coefficient of thermal expansion values which could help preventing the thermal expansion. Image 1 • Ceratonia siliqua is a novel material for PP composites. • Tensile strength increased by 32% with 5% CS into PP. [ABSTRACT FROM AUTHOR]

Nanocomposites based on graphene oxide (GO), hexagonal boron nitride (h-BN), and their hybrid GO/h-BN as nanofillers in polyurethane (PU) were prepared, and their structures and morphologies were studied. The efficient production of a few layers of nanofillers was completed using the direct liquid-phase exfoliation process. Mechanical and thermal tests were carried out to study the effect of the addition of GO, h-BN, and GO/h-BN at different wt% in the PU system. The tensile strength and Young's modulus showed an increase of up to 85% and 140%, respectively, for the composite containing 0.5 wt% of the hybrid GO/h-BN mixture. An impressive improvement of up to ~1450% in thermal conductivity was observed for the same sample when compared to neat polymer. In order to gain further insights regarding the mechanism behind the nanofiller dispersion and adhesion processes in PU, fully atomistic classical molecular dynamics simulations were carried out. Based on these simulations, it was possible to build structural models that help to explain the thermal and mechanical improvements in the hybrid GO/h-BN composites, with a focus on its stabilization energy. Image 1 • Efficient production of few layers of GO and h-BN was achieved using the direct liquid-phase exfoliation process. • Hybrid GO/h-BN in polyurethane were prepared and studied in their mechanical and thermal properties. • The tensile strength and Young's modulus showed an increase of up to 85% and 140%, respectively for the hybrid composite. • An impressive improvement of 1450% in thermal conductivity was observed for the same sample when compared to neat polymer. • Improvements in these properties suggest that this hybrid system is desirable in composites with multi-functional features. [ABSTRACT FROM AUTHOR]

An absolutely novel membrane of Poly (vinylchloride- co -vinylacetate) (PVCA) copolymer and polydimethylsiloxane (PDMS) with five different ratios were fabricated and used for further characterizations. Dense membranes of 50 μm were synthesized with ratios of PDMS and PVCA 99:1, 98:2, 97:3, 96:4 and 95:5 respectively. The separation performance is characterized by permeation studies of pure gases CO 2 , N 2 and CH 4 at two different temperatures i.e. 25 °C and 75 °C and pressure of 10 psi. The ratio of PDMS:PVCA (96:4) showed the maximum ideal selectivity of (21.1) and permeability (5595 barrer) at 25 °C for CO 2 / N 2 and CO 2 respectively. Further studies reveal that at a temperature of 25 OC membranes had high flux and higher selectivity. As the temperature was increased up to 75 OC the membranes showed the reverse behavior. Further it was found that addition of PVCA also improved the mechanical and thermal stability by 23.56% and 6.45% respectively. • Synthesis of PDMS/PVCA dense membranes. • Gas Permeability of modified membrane are tested at Gas permeation unit. • N 2, CH 4 and CO 2 permeability investigated and results were compared. • Two different temperatures (25 °C & 75 °C) are used for the investigation of gas permeability and ideal selectivity. [ABSTRACT FROM AUTHOR]

Very often, colored polyurethane (PU) foams are used in the industry, but until now the influence of the dye on the properties of PU foams has not been evaluated. Because of this, PU foam composites were prepared by the addition of red color pigment (Acid Red 74). This pigment was chosen due to its strong color that can enhance the aesthetic value of the foam. Additionally, the research allowed to determine how the pigment influenced the mechanical and functional properties of the PU foams. In this study, PU foams were prepared with the addition of commercial pigment with different weight ratios (0.1, 0.5 and 2 wt%) as a particulate modifier of PU foams composites. The features of resulting composite foams were evaluated by morphological (Scanning Electron Microscopy, SEM), thermal (Thermogravimetric Analysis, TGA), mechanical (compressive test, three-point bending test, Charpy impact test) and physical properties (apparent density, dimensional stability, contact angle, water uptake, color characteristics). Color analysis reveals that the addition of color pigment in PU foams has greatly improved the color of the PU foams to red. Moreover, it has been found that compared to the reference foam, composition with 0.1 wt% of the filler showed greater compressive strength (increase of 12%, from 0.25 to 0.28 MPa), better flexural strength (increase of 11%, from 0.41 to 0.46 MPa), less water uptake (decrease by 43%, from 9.8 to 6.5% after 24 h) as well as lower thermal conductivity (0.027 Wm−1K−1). • Pigment filler has an influence on foaming process of PU system. • PU foams containing 0.1 and 0.5 wt% of pigment filler are characterized by better mechanical and thermal properties. • Introduction of pigment filler over a certain optimal level (2 wt%) leads to deterioration of physico-mechanical properties of PU foams. [ABSTRACT FROM AUTHOR]

In this study, blends of poly (butylene succinate- co -adipate) (PBSA) and raw hydrolyzed collagen (HC), a byproduct of the tannery industry, were investigated in terms of processing by blown film extrusion/injection molding and thermal/rheological/mechanical properties. PBSA/HC blends were prepared by melting extrusion with HC contents in the range 5–20 wt%. The blown films, produced up to 10 wt% of HC, resulted flexible with satisfactory tensile properties and excellent tear resistance. While, the blends with higher HC contents, up 20 wt%, resulted suitable for the injection molding obtaining molded specimens with good tensile properties (with addition of 5 wt% of HC a maximum value of elongation at break of 1200%). Scanning electron microscopy (SEM) revealed that the HC was uniformly dispersed into the continuous phase PBSA up to 10 wt%, while at higher contents phase separation occurred without compromising their processing by injection molding. The results obtained encourage the use of HC in PBSA-based blends to produce compostable/biodegradable films or molded products for applications in agriculture due also to the fertilizing properties of HC. • PBSA and raw collagen hydrolysate blends were successfully produced by melt processing. • PBSA/HC films were produced on pilot scale blow moulding up to 10 wt% HC content. • PBSA/HC blends up to 20 wt% HC were successfully processed by injection moulding. • HC acted as a plasticizer reducing the melt viscosity in PBSA based blends. • PBSA/HC blends are suitable as biodegradable materials for agricultural applications. [ABSTRACT FROM AUTHOR]