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Stretchable strain sensors have promising potentials in wearable electronics for human motion detection, health monitoring and so on. A reliable strain sensor with high flexibility and good stability should be designed to detect human joints motions with a large deformation. Here, a simple and facile solution mixing-casting method was adopted to fabricate a highly stretchable strain sensor based on composites mixing polydimethylsiloxane (PDMS) with hybrid carbon nanotubes (CNTs) and carbon black (CB) conductive nanofillers (CNTs-CB). Bridged and overlapped hybrid CNTs-CB nanofillers structure was achieved in the composite on the basis of the morphology observation. In monotonic stretching test, the CNTs-CB/PDMS composites strain sensors exhibited high stretchability, strain-dependent sensitivity in a wide strain sensing range ( ca. 300% strain) and an excellent linear current-voltage behavior. During stretching-releasing cycles, the strain sensors presented excellent repeatability, good stability and superior durability (2500 cycles at 200% strain). Combined with the above outstanding strain sensing performances, the fabricated stretchable strain sensors were attached onto different joints of human body to monitor the corresponding human motions, demonstrating their attractive perspective in large human motions detection. [ABSTRACT FROM AUTHOR]

Superhydrophobic and superoleophilic porous reduced graphene oxide/polycarbonate (RGO/PC) monoliths with novel micro-nanoscale binary structure were first fabricated by thermally impacted nonsolvent induced phase separation (TINIPS) method. Owing to the unique pore structure, the porous monoliths possessed high specific surface area (137.19 m 2 /g) and porosity (91.3%). The superhydrophobic RGO/PC monoliths exhibited excellent capability to selectively adsorb a wide range of oils and organic solvents from water. Furthermore, the monoliths could keep a stable repellency against corrosive mediums (e.g., acidic and alkali solutions). Based on these superior properties, porous RGO/PC monoliths will be a promising candidate for high-efficiency oil/water separation to deal with water pollution. [ABSTRACT FROM AUTHOR]

Multi-walled carbon nanotubes (MWCNT)/poly (lactic acid) (PLA)/polypropylene (PP) with different polymer blend ratios were fabricated by melt processing method. When fixed the MWCNT content at 1.0 wt.%, A6P4 (PLA/PP 60w/40w) showed the lowest resistivity, which is attributed to the formation of a co-continuous structure. According to the thermodynamics prediction, MWCNT is estimated to be selectively distributed in PLA phase. To further investigate the MWCNT localization behavior in polymer blend, a two-step compounding sequence approach was utilized to fabricate Pre-PLA ( i.e. , MWCNT were firstly mixed with PLA) and Pre-PP composites. Morphology observation and rheology tests were then carried out to demonstrate the MWCNT distribution in the composites. Vapor sensing behaviors of CPCs towards organic vapors with different polarity were investigated in detail. CPCs with higher PLA content showed a higher responsivity to dichloromethane, a ‘good solvent’ to PLA. CPCs containing higher PP content exhibited a higher responsivity towards xylene due to the strong interaction between PP and the xylene vapor. While for cyclohexane, a ‘poor solvent’ to PLA and PP, all the CPCs demonstrate a low responsivity. Interestingly, the vapor sensing feature can be used to testify the MWCNT localization in the polymer blend as a diagnosis probe. [ABSTRACT FROM AUTHOR]

In this work, non-covalently functionalized reduced graphene oxide (rGO) reinforced poly(vinyl alcohol) (PVA) nanocomposites were prepared by solution mixing. The agglomeration of graphene sheets was prevented by using surface modifying agent poly(sodium 4-styrenesulfonate) (PSS). The improved mechanical properties, including the Young's modulus and tensile strength of the PVA/rGO nanocomposites compared to neat PVA were attributed to the strong interactions between PVA and rGO such as π–π, hydrogen bonding, and CH–π. A 55% maximum increase in the modulus was obtained by adding only 0.1 wt% rGO, and an increase of 48% in tensile strength was achieved by adding 0.3 wt% rGO. In addition, the thermal properties of the nanocomposites were also improved, which was attributed to the restriction of graphene oxide (GO)/rGO sheets on the chain mobility of polymers on the GO/rGO sheets surface. [ABSTRACT FROM AUTHOR]

Abstract: Shish‐kebab, which is endowed with superior strength and modulus, provides the potential to fabricate self‐reinforced polymer products. However, the injection‐molded product usually exhibits a typical skin–core structure, and the shish‐kebab is only located in an extremely thin shear layer. Therefore, the controlling and tailoring of crystal structures in complex flow field to improve the mechanical properties of the injection‐molded sample are still a great challenge. Herein, for the first time, high‐density polyethylene sample with a novel macroscopic alternating skin–core structure is achieved using a melt multi‐injection molding technique. Results show that, with increasing the amount of melt injection, the layers of skin–core structure increase in the form of arithmetic progression, and therefore the tensile strength of the samples progressively increases due to an increase of shish‐kebab content. This study demonstrates a new approach to achieve multilayer homogeneous materials with excellent tensile strength via macroscopic structural design during the practical molding process. [ABSTRACT FROM AUTHOR]

In this work, a novel flexible electrically resistive-type strain sensor with special three-dimensional conductive network was developed based on reduced graphene oxide (RGO)-decorated flexible thermoplastic polyurethane (TPU) electrospun fibrous mats. Scanning electron microscopy results indicated that RGO was localized on surfaces of the TPU fibers uniformly and formed conductive paths. The interaction between electrospun TPU fibers and RGO was investigated by using Fourier transform infrared spectra and X-ray diffraction. These fibers conductive paths connected with each other and constructed an excellent three-dimensional conductive network. The special hierarchical conductive network endowed our RGO/TPU strain sensors with a desirable integration of good stretchability and high sensitivity (gage factor (GF) of 11 in strain of 10% and 79 in strain of 100% in reversible strain regime), good durability and stability (stretch/release test of 6000 cycles) and a fast response speed. The mechanism of the evolution of residual resistance and residual strain of RGO/TPU strain sensors under cyclic loading were investigated in detail. RGO/TPU strain sensors were attached on skin or clothes to monitor various human motions. The results demonstrate that our flexible strain sensors have wide application prospects in smart wearable device. [ABSTRACT FROM AUTHOR]

The effect of a self-assembly nucleating agent, N , N ′, N ″-tricyclohexyl-1,3,5-benzenetricarboxylamide (BTCA), on the crystallization behavior of poly(lactic acid) (PLA) was probed by time-resolved Fourier transform infrared spectroscopy (FTIR) and wide angle X-ray diffraction (WAXD). The vibrational changes associated with inter- and intra-chain interactions during crystallization were monitored. In the initial period of crystallization, the order of intensity changes is as follows: 1458 cm −1 > 1210 cm −1 » 921 cm −1 , 1458 cm −1 ∼ 1210 cm −1 > 921 cm −1 , and 1458 cm −1 ∼ 1210 cm −1 ∼ 921 cm −1 for neat PLA, PLAs containing 0.1 wt% and 0.3 wt% BTCA, respectively. This indicates that BTCA can accelerate both the formation of skeletal conformational-ordered structure and, especially, the 10 3 helix one. The incorporation of BTCA changes the crystallization mechanism but has no impact on the crystal form of PLA. [ABSTRACT FROM AUTHOR]

In this paper, we used epoxy (EP) as a third component to tune the electromechanical performances of the conductive porous foam. A directional ice-template freezing method was utilized to fabricate a carbon nanotubes (CNTs)/EP/thermoplastic polyurethane (TPU) porous foam with a herringbone-like structure. CNTs were homogeneously distributed in the skeleton of the foam. The microstructure of the herringbone-like foam was studied in detail from both the directions perpendicular and parallel to the freezing front movement direction. An ultralow percolation threshold (0.088 vol%) of the conductive foam was achieved. The strength of the CNTs/TPU/EP foam was significantly enhanced with the increase of the CNTs and EP contents. When the foams were exposed to a compression strain from 0 to 70%, the resistance of the porous material decreased in a good linear manner. The foams showed a good differenciation capability towards different compression strain amplitude. Upon multiple cyclic compressive process, the change of the resistance tended to be stable after several compression loading-unloading cycles' measurement. After a pre-compression treatment, the resistance response also became much stable on the basis of the re-arrangement of the conductive network and the stabilized cells structure of the foam. The porous foam possesses a rapid response speed (about 160 ms). Our flexible porous foam with a good chemical resistance can be used in ethanol to sense the finger pressing, and it showed excellent sensing performances when applied to monitor human body motions. [ABSTRACT FROM AUTHOR]

The crystallization behavior of partially melted poly(ether ether ketone) (PEEK) was investigated by differential scanning calorimetry. The influence of pre-crystallization conditions was studied in details. After partial melting, the maximum peak shifts to higher temperature by 8.4-11.8 °C during subsequent cooling, indicating that self-nucleation remarkably enhanced the overall crystallization rate of PEEK. An interesting finding is that the self-nucleation temperature domain of PEEK is way outside the melting curve, and its magnitude is greatly large (28-35 °C). Moreover, samples that were pre-crystallized nonisothermally or from the glassy state exhibit a larger self-nucleation effect, and a larger self-nucleation temperature domain. The isothermal crystallization data were analyzed by the Avrami model. The Avrami exponent is found to be remarkably different for melts with and without self-nucleation effects, indicating that self-nucleation changes the crystallization mechanism of PEEK. [ABSTRACT FROM AUTHOR]

Nowadays, hydrogel-based sensors have drawn great attention owing to the growing demand for wearable devices. However, tailoring the property of the hydrogel sensor through a facile approach remains a great challenge. In this work, inspired by natural plants, a stretchable, adhesive and conductive hydrogel was prepared via the coordination between gallic acid (GA) and Zn2+ and chemical cross-linking. The dynamic crosslinking provided greater structural integrity for the polyvinyl alcohol / polyacrylamide (PVA/PAM) double network, endowing the hydrogel with high mechanical performance (0.25 MPa at 910% tensile strain, and 1.21 MPa at 70% compressive strain). Meanwhile, the presence of GA enabled the hydrogel with excellent repeatable adhesive performance, which greatly solved the problem of signal loss caused by poor adhesion. Moreover, the addition of ZnCl 2 enhanced the ionic conductivity and gauge factor of the hydrogel. Besides, the conductive hydrogel exhibited successively stable changes of resistance signals under different external stimuli (5–500% strains and 80–200 mm/min rates) and superior durability (over 500 cycles). The hydrogel-based wearable sensors demonstrated excellent sensing performance in detecting various human motions. The multifunctional PVA/PAM/GA-Zn2+ hydrogel has significant applications in soft robots and healthcare monitoring as the flexible strain sensor. [Display omitted] • The hydrogel was prepared via the coordination and chemical cross-linking. • The prepared hydrogel has excellent mechanical properties performance. • Plant-derived GA makes the hydrogels have good adhesion properties. • the hydrogel exhibited successively stable changes of resistance signals [ABSTRACT FROM AUTHOR]

Benefiting from its superior thermal and mechanical properties, the stereocomplex crystal (SC) of PLLA/PDLA is catching increasing interest. In this work, a systematic investigation was performed to reveal the effect of solid-state stretching on the formation of SC during annealing. Results show that as the stretching temperature was close to the glass transition temperature (T s = 60 °C), the polymer chains orientation was increased gradually with draw ratio (λ). As a result, the crystallization induction time (t 0) was shortened, the growth rate (G r) of SC was enlarged, and the crystallinity of SC (X SC) was elevated as a result of orientation-induced crystallization. Whereas, the saturation of t 0 , G r , and X SC appeared quickly when λ reached 2.7, although the orientation of polymer chains continued to increase. The reason is that in addition to orientation, strong phase separation between PLLA and PDLA was also triggered therein. The phase separation prohibited greatly the crystallization of SC due to a long time would be needed for PLLA or PDLA chains to diffuse to a distance close enough to activate the hydrogen-bonding interaction, which is the prerequisite of SC crystallization. When the stretching temperature was elevated to 75 °C, the phase separation became much weaker. So X SC was higher compared to that of the blend stretched at 60 °C to the same λ. Moreover, in the annealing temperature from 180 °C–190 °C, t 0 was much smaller for the blend stretched at 75 °C since the crystallization of SC in this temperature range is a diffusion-controlled process. [Display omitted] • Strong orientation of polymer chains and phase separation are induced by solid-state stretching. • Orientation of polymer chains and phase separation exhibit a competition effect on the crystallization of SC. • The more intense phase separation at lower stretching temperature gives rise to a longer crystallization. induction time [ABSTRACT FROM AUTHOR]

In this study, a composite hydrogel with a low swelling ratio, excellent mechanical properties, and good U (VI) adsorption capacity was developed by incorporating a metal-organic framework (MOF) with a poly (acrylamide- co -acrylic acid)/chitosan (P(AM-co-AA)/CS) composite. The CS chain, which contains NH 2 , reduces the swelling ratio of the hydrogel to 4.17 after 5 h of immersion in water. The coordinate bond between the MOF and carboxyl group on the surface of P(AM-co-AA)/CS improves the mechanical properties and stability of P(AM-co-AA)/CS. The U(VI) adsorption capacity of P(AM-co-AA)/CS/MOF-808 is 159.56 mg g−1 at C 0 = 99.47 mg L−1 and pH = 8.0. The adsorption process is well fitted by the Langmuir isotherm and pseudo-second-order model. The P(AM-co-AA)/CS/MOF-808 also exhibits good repeatability and stability after five adsorption–desorption cycles. The uranium adsorption capacity of the developed adsorbent after one month in natural seawater is 6.2 mg g−1, and the rate of uranium adsorption on the hydrogel is 0.21 mg g−1 day−1. [Display omitted] [ABSTRACT FROM AUTHOR]

Tailored p-Orbital Delocalization by Diatomic Pt-Ce Induced Interlayer Spacing Engineering for Highly-Efficient Ammonia Electrosynthesis (Adv. Keywords: diatomic Pt-Ce; chemical affinity; electrochemical nitrate reduction; interlayer spacing regulation; p-orbital delocalization EN diatomic Pt-Ce chemical affinity electrochemical nitrate reduction interlayer spacing regulation p-orbital delocalization 1 1 1 02/14/23 20230210 NES 230210 B Electrochemical Nitrate Reduction b In article number 2203201, Johnny C. Ho and co-workers design 2D SnS nanosheets with tailored interlayer spacing, including both expansion and compression, through active diatomic Pt-Ce pairs. Diatomic Pt-Ce, chemical affinity, electrochemical nitrate reduction, interlayer spacing regulation, p-orbital delocalization. [Extracted from the article]

Conductive hydrogels (CHs) have attracted considerable attentions in the fields of wearable electronics, disease diagnosis, and artificial intelligence. However, it is still a great challenge to prepare a single CH system with integrated characteristics of high stretchability, good transparency, and multisensory function through a simple fabrication process. Herein, carboxylic cellulose nanofibers (CCNF) were used to assist the homogeneous distribution of opaque conductive poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT: PSS) into the crosslinked polyacrylamide network for the fabrication of stretchable and transparent interpenetrating network CH, aiming for a high-performance multisensory system. As expected, the ready formation of hydrogen bonds between the water molecules and a great deal of hydrophilic groups in the hydrogel endow the obtained CH with excellent humidity response behavior in a wide range (0–85%), and the introduction of CCNF and PEDOT: PSS is proved to be an effective strategy to enhance the humidity sensitivity, exhibiting great potential for the noncontact sensing of human respiration and finger movement. Meanwhile, it also displays excellent strain sensing behavior with favorable sensitivity in a broad range (0–837 %), fast response and reliable stability and reproducibility. Importantly, our prepared CH can also detect and discriminate complicated human activities and physiological signals. All these demonstrate the superiority of our prepared CH for the new generation of flexible wearable electronics. [Display omitted] • Stretchable and transparent hydrogel with multiple sensing ability was prepared. • The hydrogel possesses favorable humidity response to a RH up to 85 %. • The hydrogel displays fast and reliable strain sensing capacity in a wide strain range. [ABSTRACT FROM AUTHOR]

Micellar hydrogels formed by direct self-assembly of natural compounds have attracted widespread attention as delivery systems owing to their distinctive structures, excellent biocompatibility and simple preparation methods. Herein, we report on glycyrrhizic acid (GA), which is directly self-assembled into micellar hydrogels to encapsulate curcumin (Cur) through non-covalent interactions without excipients or structural modifications. Owing to their reversible non-covalent interactions, the micellar hydrogels have outstanding shear-thinning, self-healing ability and temperature-responsive behavior. Notably, the mechanical properties and release rates of the micellar hydrogels can be easily tuned by adjusting the concentration of GA. Furthermore, the GA@Cur micellar hydrogels have exhibited superior stability, remarkable biocompatibility and better antioxidant properties than free Cur, benefiting from improved solubility and stability. In brief, this micellar hydrogel inherits the advantages of both micelles and hydrogels: it has characteristics of micelles, naturally encapsulates Cur and has the ability of hydrogels to control long-term release. We believe this study will offer an innovative strategy to deliver Cur efficiently. [Display omitted] [ABSTRACT FROM AUTHOR]

Highly sensitive and flexible capacitive sensors are in great demand for wearable electronics, which can be achieved by preparing micropatterns on their dielectric layer surface. However, most micropatterns are often molded with the silicon template acquired by complex processes which are very time-consuming and costly. Here, a dielectric layer with micropatterned arrays was prepared on the thermal plastic polyurethane (TPU) film with the help of a hot-air-gun, then assembled with an ITO/PET electrode to develop a capacitive sensor with a sandwich structure. The capacitive sensor based on TPU/ITO/PET composites exhibits sensitivity of over 0.026 kPa−1, shorter response/recovery time of 99 ms, wide working range (0–13 kPa) and remarkable stability over 5000 cyclic pressing or bending. Interestingly, such sensor can monitor various physiological signals of people (e.g., voice signal, finger bending and breath). More importantly, it can distinguish different sign languages according to capacitive changes in the case of different finger gestures. The method proposed in this study will paves a new avenue for the facile preparation of micropatterned surface to improve the performance of flexible capacitive sensors. The present work represents a facile and efficient method to achieve capacitive sensor that can not only exhibit excellent sensing performances, but also it can detect a series of physiological signals and realize sign language interpretation. [Display omitted] • A cost-effective method is proposed to fabricate micropatterned surface. • Micropatterned capacitive sensor has remarkable sensing performances. • Capacitive sensor can monitor various physiological signals in the body. • Capacitive sensor can realize sign language interpretation. [ABSTRACT FROM AUTHOR]

• Waterproof conductive fiber with microcracked synergistic conductive layer was designed. • High sensitivity and wide working range were achieved for the conductive fiber strain sensor. • Tunable sensing performance was achieved for the conductive fiber strain sensor. • The sensor can precisely distinguish various human movements and physiological signals. With the rapid development of wearable smart electronic devices, flexible strain sensors with high sensitivity in a wide working range are urgently demanded. Meanwhile, good self-cleaning and anti-corrosion properties are also essential for daily use. Herein, a waterproof conductive spandex fiber strain sensor with microcracked synergistic Ag nanoparticles (AgNPs)-carbon nanotubes CNTs conductive layer was designed and fabricated via the solvent swelling, non-solvent-induced phase separation (NIPS), and low surface energy treatment process. Benefiting from the stable synergistic conductive network and the ultrasensitive microcrack structure, the sensor exhibits excellent overall strain sensing performances, including high sensitivity (gauge factor is 48,310 within 335–400% strain), wide working range (0–400%), ultralow detection limit (0.1%), fast response/recovery time (80 ms/100 ms), and long-term fatigue resistance over 10,000 cycles, making it reliably and precisely distinguish both violent human movements and subtle physiological signals. More importantly, strain sensing range and sensitivity of the sensor can also be effectively tunned through changing the AgNPs loading in the synergistic conductive network, enabling it to be applicable for different application scenarios. What's more, the waterproof surface with good self-cleaning and anti-corrosion properties also endows the sensor with great potential for real-time body motion monitoring under humid and underwater environments without being interfered. This study provides a facile one-step method for the fabrication high-performance flexible strain sensor. [ABSTRACT FROM AUTHOR]

To explore the possibility of using surface coating to reduce environmental stress cracking (ESC) of transparent polycarbonate (PC) parts, silicone coated and SiO 2 coated PC were tested in a self-made three-point bending apparatus in the presence of ethanol. The variation of stress with time was recorded, and the surface cracking was observed to evaluate the ESC resistance of samples. Slower stress relaxation rates and fewer surface cracks indicated that silicone coating improved the ESC resistance of PC, but SiO 2 coated PC was found to be no better than that of uncoated PC. Silicone coating reduced the absorption of ethanol in PC, weakening the surface plasticization, thus hindering the formation and development of cracks in PC. Nanoindentation test results showed that the mechanical properties such as hardness and elastic modulus of silicone coating are a better match for PC than SiO 2 coating. This allows the silicone coating to have a favorable effect in providing continuous protection for PC under the combined action of ethanol and stress. [ABSTRACT FROM AUTHOR]

The influence of crystalline memory effect on poly(lactic acid) (PLA) crystallization was probed by time-resolved Fourier transform infrared spectroscopy (FTIR). The melt with different degrees of order was prepared by melting at various temperatures. The vibrational changes associated with inter- and intra-chain interactions during crystallization were monitored. In the initial period of crystallization, the order of intensity changes is as follows: 1458 cm −1 > 1210 cm −1 ≫ 921 cm −1 , 1458 cm −1 > 1210 cm −1 > 921 cm −1 , and 1458 cm −1 > 1210 cm −1 ∼ 921 cm −1 for PLA melted at 190, 170, and 168 °C, respectively. With increasing the degree of order, both the formation of skeletal conformational-ordered structure and, especially, the 10 3 helix structure are accelerated. The influence of memory effect on the crystallization kinetics was also discussed based on the Avrami model. [ABSTRACT FROM AUTHOR]

Melt-stretched isotactic polypropylene (iPP) filled with different weight fractions (0, 0.1, 0.2 and 0.4 wt %) of β-nucleating agent (β-NA) was extruded via a single screw extruder with a slit die and immediately melt-stretched at the die exit. The microstructure and mechanical properties (i.e., monotonic tensile, step-cycle and stress relaxation behavior) of these samples were analyzed. Unexpectedly, the lamellar branching of β-crystal, which is similar to lamellar branching of α-crystal, is observed in melt-stretched β-nucleated iPP. More interestingly, it is found that, compared with other samples, iPP containing 0.2 wt % of β-NA has the best mechanical properties. Through thorough analysis of various structural characterizations, the improved tensile strength obtained from step-cycle tests and viscous force obtained from stress relaxation measurements for iPP with 0.2 wt% of β-NA is ascribed to lamellar branching of β-crystal. The study is an example of preparing high performance polymers via practical polymer processing methods. [ABSTRACT FROM AUTHOR]

In this letter, both the viscoelastic and electrical properties of poly(methyl methacrylate)/carbon black (PMMA/CB) nanocomposites with different CB concentrations prior to and after annealing were investigated. The linear steady-state recoverable compliance of pure PMMA is independent of annealing as it reflects only polymer-polymer interactions. While the conductivity of PMMA/CB nanocomposites increases gradually with annealing, and the viscoelastic properties show different regions of response depending on the CB concentration. At CB contents below the percolation threshold the recoverable compliances increase after annealing, whereas the reverse trend is found at CB contents above the percolation threshold. This behavior is related to the interplay between network formation and particle-particle interactions. [ABSTRACT FROM AUTHOR]

The strain sensing behavior of multi-walled carbon nanotubes (MWCNT)/epoxy (EP) conductive composites subjected to tensile strain was studied in detail. With increasing the load to rupture, the responsivity (ΔR/R 0 , R 0 is the original resistance, ΔR is instantaneous change in resistance) increased in a linear fashion and then began to decrease at a critical strain ( ε c ), which was remarkably different from the thermoplastic conductive composites only with a monotonic increase of the responsivity. It was attributed to the decrease of the nanotube contact points, the increase in the gaps before ε c , and the reorientation and violent alignment of nanotubes in the zones of high local deformation (after ε c ). In addition, when the extension-retraction cycles were applied, the values of max ΔR/R 0 showed a distinct tendency with different strains around the ε c . These behaviors were attributed to the competition of network destruction and reconstruction during the cyclic deformation. The mechanism of this unique sensing behavior was proposed as well. [ABSTRACT FROM AUTHOR]

Flexible and wearable strain sensors based on conductive polymer composites (CPCs) for human motion detection have been highlighted recently. Herein, two flexible conductive composites were fabricated by mixing matrix polydimethylsiloxane (PDMS) with zero-dimensional conductive filler carbon black (CB) and one-dimensional carbon nanotubes (CNTs), respectively. A low percolation threshold of CB/PDMS (0.48 vol%) was achieved, while this value was higher than that of CNTs/PDMS (0.13 vol%). In strain-dependent response tests, compared with CNTs/PDMS with a gauge factor ( GF ) of 4.36 (a strain of 10%), CB/PDMS composites showed a higher sensitivity with a larger GF of 15.75 (a strain of 10%). A good reproducibility was obtained in stretching-releasing process for the two composites. In long-term cyclic test, CB/PDMS showed more stable sensing behaviors, while a slight drifting and fluctuation was observed for CNTs/PDMS. Generally, two composites both possessed satisfactory durability. Mathematical models were proposed to explain the mechanism of the distinct strain sensing behaviors. A smart glove was assembled to monitor the finger motion to evaluate the application of the two composites as flexible strain sensors. [ABSTRACT FROM AUTHOR]

Polycarbonate (PC) monolith with three-dimensional interconnected mesoporous nest-like structure was first fabricated by thermally impacted nonsolvent-induced phase separation (TINIPS) method. Owing to continuously interlaced nanofibrous skeleton, the monolith possessed a high specific surface area of 95.02 m 2 /g. This novel structure also contributed to the improvement of hydrophobicity so that a high water contact angle of 143.9° was obtained. Furthermore, the as-prepared monolith could effectively adsorb various types of oils. Based on such a unique structure as well as these outstanding properties, the PC monolith will play a big role in the field of oil sorbents. [ABSTRACT FROM AUTHOR]

Additive manufacturing technologies have been proved as a promising method to achieve electrocatalysts with periodic micro-size pores, while the nano-sized interspace of the material structures and their corresponding gas bubbles transfer process are not explored in detail. Herein, we employ the shear force alignment in additive manufacturing to design NiMo-based structures with anisotropic porous channels as electrocatalysts for hydrogen evolution reaction (HER) in seawater. Based on the complementary experimental and theoretical investigation, the unique anisotropic structure not only fully exposes the active sites in the electrolyte, but also facilitates the rapid electrolyte-hydrogen phase conversion during electrochemical reactions. In this case, the obtained 3D electrode exhibits superior electrocatalytic performance and excellent long-term operational stability with an extremely low overpotential of ∼150 mV at a current density of 500 mA/cm2 in 1 M KOH seawater. This work will provide a practical scenario for designing highly-efficient HER electrocatalysts. [Display omitted] • Electrocatalysts with the anisotropic structure were fabricated with 3D printing technology. • The anisotropic porous structure was beneficial for gas bubble transfer behaviors. • The catalyst exhibits an overpotential of ∼150 mV (500 mA/cm2) in 1 M KOH seawater. [ABSTRACT FROM AUTHOR]

The mechanical properties and microstructure of injection molded isotactic polypropylene parts with high orientation before and after annealing are analyzed. The mechanical properties of the annealed samples are improved effectively. Through thorough analysis of various structural characterizations, a microstructural model based on the fact that the total length of long period kept constant to analyze the variation of mechanical properties is proposed. It is suggested that the increase of overall crystallinity, the recombination of crystalline phase, and the increase of amorphous phase, respectively, are beneficial for the improvements of the strength, stiffness, and toughness of annealed samples. [ABSTRACT FROM AUTHOR]

To explore the effect of physical aging on environmental stress cracking (ESC) behavior of polycarbonate (PC), sub-T g annealing was utilized as a method for accelerated aging. Injection molded samples were annealed at 130 °C for different time varying up to 96 h. A three point bending apparatus was used to evaluate critical stress for crazing and to record the variation of stress with immersion time at constant strain. The ESC results indicated that the critical stress for crazing initiation of PC in ethanol is increased by sub-T g annealing. However, the resistance of annealed PC to ESC with immersion time during the stress relaxation test depends on the level of initial stress. When a relatively low initial stress was used, a short time (24 h) of sub-T g annealing reduced the stress relaxation rate and decreased the number of cracks on the surface of PC. However, under higher initial stress, the stress relaxation rate of PC had a slight change only when the annealing time was prolonged about threefold (72 h). This can be explained by the formation of cohesional entanglement sites during the sub-T g annealing process, which was demonstrated by the thermal and dynamic mechanical tests. [ABSTRACT FROM AUTHOR]

A novel approach, i.e. manipulating the size of incorporated polymer matrix particles, was proposed to tune the positive temperature coefficient (PTC) characteristics of carbon nanotubes (CNTs)/polypropylene (PP) composites with a segregated microstructure. For the conductive properties of CNTs/PP composites, the percolation threshold decreased from 1.32 vol% to 0.44 vol% when the matrix particle size enlarged from 20 to 1200 µm, showing an inverse correlation effect. The controllable PTC characteristics in resistivity are attributed to the microstructure development of conductive pathways and the heat-induced volume expansion of polymer matrix particles. An extremely high PTC material has also been achieved through this method. The present work provides an effective route to acquire a tunable temperature-resistivity sensor. [ABSTRACT FROM AUTHOR]

Isotactic polypropylene (iPP)/glass fiber (GF) composites with different specific interfacial features ( viz ., α-spherulite, α-cylindrite and β-cylindrite) were prepared via shear-induced interfacial crystallization. α-spherulite, α-cylindrite and β-cylindrite were successively encouraged at the interface between iPP matrix and GF with increasing the fiber-pulling speed. Moreover, the composite specimens containing β-cylindrite exhibited remarkably higher interfacial shear strength (IFSS) than those containing α-spherulite or α-cylindrite, as demonstrated by the single fiber fragmentation test (SFFT). More interestingly, simultaneously improved tensile strength and toughness were observed in the presence of β-cylindrite. This study offers a new insight that β-cylindrite produced by shear is an alternative approach to achieve comprehensive mechanical properties for the iPP/fiber composite systems. [ABSTRACT FROM AUTHOR]

Structural evolution of poly(lactic acid) (PLA) upon uniaxial stretching was studied with in-situ polarized infrared spectroscopy measurements, and its structural change affected by annealing was also investigated. Band shifting was used to reflect the structural ordering process. It was found that the band at 1302 cm −1 always moves to low wavenumbers before crystallization, indicating the occurrence of intermolecular packing ordering. However, the band at 869 cm −1 shifts to high wavenumbers, which is related to the transition from the amorphous phase to the ordered phase. Interestingly, during stretching, the shifting for the band at 1302 cm −1 always occurs before that for the lower wavenumber band, whereas these two band shifts take place simultaneously under annealing. Based on the different characteristics of the structural evolution under stretching and annealing processes, a critical temperature was found at around 63 °C, which influences the effect weight of kinetic and thermodynamic factors to the crystallization behavior. The effect of the drawing temperature on crystallization and mechanical property of PLA films was also analyzed. [ABSTRACT FROM AUTHOR]

The electrically conductive nanocomposites composing of different concentrations (0.05–1.5 wt%) of reduced graphene oxide (RGO) in the thermoplastic polyurethane/polypropylene (TPU/PP, 55/40) matrix with a fine co-continuous structure were fabricated by solution-flocculation and melt-mixing process using a micron twin-screw extruder. Both thermodynamic and kinetic theoretical analysis predicated the preferential location of RGO in the TPU rather than PP phase. Both optical microscope and field emission scanning electron microscopy (FESEM) observations verified this theoretical dispersion predication. The homogeneous dispersion of RGO in the TPU matrix is confirmed by wide-angle X-ray diffraction (WAXD) patterns and transmission electron microscope (TEM) observation. A very low percolation threshold of 0.054 wt% was achieved owing to high conductivity of RGO and favorable double percolation effect. The tensile strength and elongation at break of the composites with RGO content of only 0.5 wt% were improved by 341.9% and 354.3%, respectively. The present work provides a guideline for an efficient, facile fabrication technique of graphene based conductive polymer nanocomposites with high electrical conductivity and improved mechanical properties. [ABSTRACT FROM AUTHOR]

Liquid-sensing behaviors of carbon black (CB)/polyamide 6 (PA6)/high-density polyethylene (HDPE) composite containing conductive electrospun fibrous network were investigated by detecting electrical resistance variations toward different solvents. The material exhibited a good sensing selectivity, which could be predicted by Flory-Huggins interaction parameter χ . In immersion-drying runs (IDRs), the composite showed a large liquid-sensing responsivity but poor reproducibility toward 'good solvent' xylene. After long-term immersion treatment in xylene, the metastable conductive pathways became stabilized, and a better reproducibility was finally achieved. Absorption/desorption equilibrium state of the composite in 'moderate' or 'poor' solvents was reached more easily than that in good solvent. Additionally, more rapid response, higher sensing responsivity, and better reproducibility of the composite in 'moderate solvent' cyclohexane were observed at a higher environment temperature. These results indicated that liquid-sensing behaviors of conductive polymer composites could be tailored by tuning the microstructure or utilizing the pretreatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Solar-heated porous F-rGO@TPU monolith with superhydrophobicity was fabricated. • The as-prepared monolith possessed outstanding photothermal performance. • The flexible monolith exhibited excellent recyclability for oil/water separation. • The self-heating monolith could continuously recover viscous crude oil from water. Frequent occurrences of oil spill accidents have posed a serious threat to ecological system and human health, hence it is imperative to explore new-typed absorbent materials to efficiently clean up high-viscosity crude oil in an environmentally-friendly way. Herein we reported a reduced graphene oxide-wrapped and fluoroalkylsilane-modified thermoplastic polyurethane porous monolith (abbr. F-rGO@TPU monolith) with superior photothermal effect for solar-driven high-efficiency cleanup of crude oil spill. Owing to superior superhydrophobicity (water contact angle of 153°) and porosity (87.4 %), the as-prepared F-rGO@TPU monolith possessed high saturated absorption capacity (6.5–53.7 g/g) and splendid oil/water separation efficiency (over 99.3 %) for various low-viscosity oils/organic solvents. Excellent reversible compressibility and fatigue resistance (1000 compression cycles under 80 % strain) allowed the monolith to repetitively absorb oil via simple manual squeezing. By virtue of the outstanding photothermal effect of reduced graphene oxide coating, the F-rGO@TPU monolith exhibited almost full absorption (96.0 %) of solar spectrum (wavelength range of 250–2500 nm) and efficient light-to-heat conversion capability (achieving 80 °C in 5 min under 1.0 kW/m2 solar irradiation), enabling it to in situ reduce the viscosity of crude oil for rapid absorption. More importantly, the solar-heated monolith could continuously and fast separate crude oil/water mixture by a pump-assisted absorption device (crude oil flux of 510 kg/(m2·h)), revealing immense potential in oil spill remediation. [ABSTRACT FROM AUTHOR]

[Display omitted] • UHMWPE/OMS NPs superhydrophobic nanocomposite foams were fabricated by scCO 2 foaming. • The viscoelasticity and the cell density were significantly enhanced with the addition of 1 wt% OMS NPs. • Composite foams achieved a high WCA of 158.2 ± 1° and a low SA of 1.7 ± 0.4°. • The foam had outstanding separation efficiency and stability in separating light and heavy oils from water. Superhydrophobic foams are promising substances for removing leaked oil from water. However, producing superhydrophobic foams with stable high performance using a low-cost, scalable, and environmentally friendly means is a challenge. Herein, superhydrophobic nanocomposite foams comprising of ultra-high molecular weight polyethylene (UHMWPE) and modified silica nanoparticles (NPs) were developed using melt blending and supercritical CO 2 foaming. Long carbon chains grafted on silica NPs formed a shell with a thickness of 100 nm, which rendered the NPs hydrophobicity and generated entanglements with UHMWPE matrix. The optimum foam with an average cell size of 41.5 μm achieved a high water contact angle of 158.2 ± 1° and a low sliding angle of 1.7 ± 0.4°, attributing to the micro-nano hierarchical structure constructed by the porous structure and the modified NPs. The foam remained superoleophilic and demonstrated high efficiency in separating both light and heavy oils from water. A relatively high oil absorption capacity of 2.8 to 7.2 g/g was achieved towards various oils and solvents, and separation efficiency of over 99 % could be maintained after ten cycles of reuse. This work provides a facile and scalable method to produce superhydrophobic UHMWPE nanocomposite foams with stable high performance for effective oil absorption from water. [ABSTRACT FROM AUTHOR]

Solar vapor generator (SVG) is undoubtedly a sustainable water treatment technology and good candidate to resolve the water shortage. However, the non-degradable polymer based SVG will bring extra environmental risk when they are scrapped. Herein, we fabricate a degradable interfacial solar vapor generator (DISVG) using PBAT monolith with hierarchical porous morphology via in-situ polymerization of PDA and dip-coating of MXene. Contributed to the MXene and PDA's synergetic effects, the DISVG demonstrates promising solar absorbance (up to 97.07 %), superhydrophilicity, and high evaporation efficiency. Consequently, the DISVG exhibit a high evaporation rate of 1.87 kg m−2 h−1 with a solar steam efficiency of 86.19 % under 1 sun irradiation. The DISVG shows excellent salt and oil resistance because of its good hydrophilicity. Moreover, the DISVG possesses excellent purification capability that can reject above 99 % ions in seawater and dyes in sewage. This research demonstrates a sustainable strategy for the fabrication of DISVG with environmentally friendly, highly efficient and well reliable solar vapor generators for seawater desalination and sewage purification. [Display omitted] • A convenient and cost-effective approach was proposed to fabricate degradable interfacial solar vapor generator (DISVG). • Excellent solar driven evaporation rate and efficiency was achieved resulting from the synergetic effects of MXene and PDA. • High evaporation rate was obtained with assistance of few MXene dosage. • Salt ions (above 99%) in real seawater and dyes in simulated sewage were efficiently removed by the DISVG. [ABSTRACT FROM AUTHOR]

With the rapid development of new-generation wireless communication technologies and portable intelligent electronic devices, the development of composites with excellent thermal conductivity and electromagnetic shielding properties has become an urgent challenge. In this work, a unique fibers-induced segregated-like structure strategy for fabricating thermoplastic polyurethane/polydopamine/silver (TPU/PDA/Ag) composites film with high thermal conductivity (TC) and excellent electromagnetic interference (EMI) shielding performance is demonstrated via electrospinning-electroless depositing-pressing technology. The TPU/PDA/Ag composites film exhibit excellent in-plane TC of 20.9 W/(m⋅K) at 75 wt% Ag loading, which shows excellent thermal management capability as heat spreaders of high-power light-emitting diode (LED) modules in practice. Meanwhile, the composites film presents outstanding EMI shielding efficiency of 109 dB (8.2–12.4 GHz) with a thickness of 45 μm and prominent EMI shielding reliability after 1000 cycles of bending. In addition, the composites film shows good tensile strength (12.1 MPa), elongation at break (108.0%), and toughness (11.59 MJ/m3). The obtained TPU/PDA/Ag composites film achieves the desired balance among thermal conductivity, EMI shielding, and mechanical properties, indicating broad application prospects in new-generation wireless communication technologies and portable intelligent electronic devices. [ABSTRACT FROM AUTHOR]

Stretchable strain sensors with integrated attributes of flexibility and robustness are urgently required owing to their promising applications in healthcare monitoring and environment detection. Herein, we achieved a highly stretchable thermoplastic polyurethane (TPU) mat (PUM) through electrospinning, then decorated with polyaniline (PANI) nanoparticles bridged by reduced graphene oxide (rGO) nanosheets by in-situ polymerization and ultrasonication. The rGO/PANI/TPU mat (GPTM) was then assembled as the strain sensor (GPTSS), showing a wide sensing range of 0.1%–300% strain, high gauge factor (GF) of 3000.2, favorable sensing stability, short response time (90 ms) and excellent long-term durability after 10000 stretching/releasing cycles, which endows the strain sensor with high discernibility for detecting intricate human motions. The GPTSS shows the capacity to precisely monitor ammonia gas (as low as 5 ppm), which can be used to detect harmful gases. The integrated capabilities of strain sensing and environmental monitoring promote the progress of high-performance electronics. [Display omitted] [ABSTRACT FROM AUTHOR]

Via coextrusion blow film molding, sandwiched functional polymer films (SFPFs) were massively fabricated, whose skin and core layer are respectively low density polyethylene (LDPE) and polyethylene oxide (PEO) phase. Moreover, such SFPFs show rapidly and reversibly switchable transparency during cyclic melting-crystallization process, which can be used for thermo-photo door in photocatalytic reaction system and serve as smart windows achieving programmable luminance and privacy of room by wireless remote control. [Display omitted] • The commercial but low-cost thermoplastics elaborately serve as skin and core layer. • SFPFs were easily fabricated by a cost-efficient and environmentally friendly method. • SPFFs show reversibly and rapidly switchable transparency on cyclic heating cooling. • SPFFs are successfully used for thermo-photo door and serve as smart windows. Polymer functional films (PFFs) with switchable transparency have drawn increasing interests recently for their promising applications. Unfortunately, it still remains a challenge to fabricate large-area temperature-driven PFFs by a facile, continuous and environmentally friendly method. Herein, via coextrusion blow film molding, sandwiched polymer functional films (SPFFs) were massively fabricated, whose skin and core layer are respectively low density polyethylene (LDPE) and polyethylene oxide (PEO) phase. Moreover, such SPFFs show wide range of reversibly switchable transparency and rapid response to varied temperatures during cyclic melting-crystallization process. In view of this, the as-prepared SPFFs can be used for thermo-photo door in photocatalytic reaction system and serve as smart windows. This work proposes a facile, cost-efficient and environmentally-friendly method for developing low-cost, durable and large-area SPFFs, and first builds the relationship between crystallization performance and functional application in industrial product, providing a new pathway to build the functional architecture based on the concept of polymer "structuring" processing. [ABSTRACT FROM AUTHOR]

A biomimetic nanocomposite scaffold with HA formation on the electrospun poly(ɛ-caprolactone) (PCL)/nanocellulose (NC) fibrous matrix was developed in this study. The electrospun PCL/NC fiber mat was built and then biomineralized by treatment in simulated body fluid (SBF). Using such a rapid and effective procedure, a continuous biomimetic crystalline HA layer could be successfully formed without the need of any additional chemical modification of the substrate surface. The results showed that the introduction of NC into composite fibers is an effective approach to induce the deposition of HA nucleus as well as to improve their distribution and growth of a crystalline HA layer on the fibrous scaffolds. The water contact angle (WCA) of the PCL/NC/HA scaffolds decreases with increasing NC content and mineralization time, resulting in the enhancement of their hydrophilicity. These results indicated that HA-mineralized on PCL/NC fiber can be prepared directly by simply using SBF immersion. [ABSTRACT FROM AUTHOR]

Electrospinning is not only a technique to fabricate macroscopic fiber but also a method to control the microstructure. In this study, high-temperature solution electrospinning was used to prepare isotactic polypropylene (iPP) fibers. Scanning electron microscope (SEM) observation indicates that a single electrospun iPP fiber consists of many nano-fibrils. Based on SEM observation, these nano-fibrils are shish-kebab structure. Electrostatic elongational force involved in the electrospinning process is considered to be responsible for the development of shish-kebab structure. [ABSTRACT FROM AUTHOR]

A distinct skin-core-water-channel structure was formed in water-assisted injection molded low molecular weight high density polyethylene. A large number of well-developed banded spherulites were observed in core region. Two types of shish-kebabs, i.e., shish-kebabs without and with twisted lamellae, were appeared in both skin and water-channel region. The results imply that the formation mechanisms of twisted lamellae in banded spherulites and shish-kebabs are different, but both depend on the level of applied shear stress. [ABSTRACT FROM AUTHOR]

In this paper, carbon black (CB), carbon fiber (CF), and hybrid CF/CB were introduced into polypropylene (PP) to fabricate different conductive composites by melt mixing, respectively. The combined effects of CF and CB on the electrical and liquid sensing properties of PP-based composites were investigated in detail. In virtue of the co-supporting conductive network, percolation threshold of the CF/CB/PP composite was reduced apparently upon the addition of 8 wt.% CF. For liquid sensing measurements, CF/CB/PP conductive polymer composites (CPCs) exhibited a superior liquid sensing behavior with higher responsivity, rapider response and better stability in contrast to the counterpart CB/PP. In addition, the response curves are found to be remarkably characteristic for discriminating different kinds of organic solvents. The present paper provides a new route to tailor the liquid sensing properties of CPCs. [ABSTRACT FROM AUTHOR]

Hydroxyl functionalized multiwalled carbon nanotubes (H-MWNTs) were silanized using 3-aminopropyltriethoxysilane (APTES) in order to improve the dispersion and interfacial interaction in composites. MWNT/polycarbonate (PC) composites filled with H-MWNTs and silanized MWNTs (S-MWNTs) were fabricated by melt mixing and injection molding. Fourier transform infrared spectrometry (FTIR) and energy dispersion X-ray spectroscopy (EDS) were employed to prove the presence of APTES on the surface of S-MWNTs. In addition, thermogravimetric analysis (TGA) was used to evaluate the relative amount of introduced APTES. The microstructure and mechanical property of both composites were investigated by scanning electron microscopy (SEM), transmission electron microscope (TEM), tensile test and dynamic mechanical analysis (DMA). The SEM and TEM images showed that S-MWNT/PC composites had better dispersion and interfacial adhesion than H-MWNT/PC composites. A reinforcing and toughening effect on tensile behavior of composites was obtained after silane functionalization. The storage modulus of composites increased markedly as a function of MWNTs content, especially for the composites with S-MWNTs. In summary, the silanization can improve the dispersion of MWNTs and the interfacial adhesion between MWNTs and PC so as to enhance the mechanical properties of composites. POLYM. COMPOS., 37:1914-1923, 2016. © 2015 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Isotactic polypropylene (iPP) based single-polymer composites (SPCs) were prepared by introducing iPP fibers into the molten or supercooled homogeneous iPP matrix. The influences of fiber introduction temperature ( T i ) on the resultant morphology of transcrystallinity (TC) and mechanical properties of SPCs were investigated via a polarized optical microscopy (POM) and a universal tensile test machine. The effects of interfacial crystallization on mechanical properties were also studied. The tensile strength of SPCs was observed to increase firstly and to reach a maximum value at T i = 160 °C, and then to decrease with further increasing the T i . Wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM) and POM were employed to understand the mechanical enhancement mechanism. It is found that the enhanced tensile strength of SPCs was strongly dependent on the synergistic effects of TC, high orientation degree of iPP fibers and good adhesion between the iPP fiber and the matrix. [ABSTRACT FROM AUTHOR]

Electrospun polyamide PA 66 nanofiber bundles were mechanically strengthened via compositing with polyvinyl alcohol (PVA). The highest tensile strength (126.4 MPa) was achieved for the bundles immersed in the solution with 5.0 wt% PVA, indicating sufficient PVA filling between nanofibers after drying the impregnated nanofiber bundles. The disappearance of voids for the bundles immersed in the PVA solution indicated a superb interface adhesion, which was responsible for the excellent mechanical properties of the composite bundles. Furthermore, the step-cycle and stress relaxation tests were carried out to shed light on the deformation evolution and the viscous stress of the bundles. The results further demonstrated the excellent mechanical properties of the composite bundles. [ABSTRACT FROM AUTHOR]

In this work, isotactic polypropylene (iPP) melt was slowly extruded through a slit die of a single-screw extruder. Once the iPP melt left the die, it was uniaxially stretched at different stretching rates (SRs). Via this process its microstructure can be manipulated, it was subsequently investigated by wide-angle X-ray diffraction (WAXD), small-angle X-ray scattering (SAXS), differential scanning calorimetry (DSC), polarized optical microscopy (POM), and Fourier transform infrared spectroscopy (FTIR). Furthermore, the mechanical properties (including tensile strength, modulus, toughness, and strain-hardening) were investigated. The results showed that the tensile strength and modulus of the melt-stretched iPP films gradually increased with increasing SRs. In addition, the toughness and elongation at break showed maximum values for iPP films melt-stretched at 30 cm/min. Moreover, compared with other melt-stretched films, the iPP films melt-stretched at 90 cm/min exhibited an obvious strain-hardening behavior at lower strain. [ABSTRACT FROM PUBLISHER]

Conductive polymer composites (CPCs) have found applications as eco-friendly vapor sensor. In this study, ramie fiber (RF) was incorporated into poly (lactic acid) (PLA), an eco-friendly polymer, through a premixing process of conductive fillers (carbon black (CB) and carbon nanotubes (CNTs)) and RF. The introduction of RF increases the crystallinity of composites without sacrificing electrical properties. The influence of RF on the vapor sensing behaviors of the CPC was investigated in detail. Compared with those systems with only conductive fillers, i.e. , CB/PLA and CNT/PLA, the RF embedded CPCs show higher electrical conductivity with lower percolation threshold, better shape stability toward ‘good solvent’ such as dichloromethane, and excellent reversibility upon ‘poor’ solvent. The increased crystallinity and the interaction between conductive fillers and RF are responsible for the phenomenon. To illustrate the conductive network evolution during tests, a schematic was proposed. The results suggest that conductive polymer composites containing RF can be applied as a promising eco-friendly vapor sensor. [ABSTRACT FROM AUTHOR]

Resistivity–temperature characteristics of conductive multi-walled carbon nanotubes (MWCNT)/epoxy (EP) composite were studied during a heating-cooling run (HCR) with different top test temperatures. The values of R e (room-temperature resistance at the end of a HCR) decrease with increasing the top test temperature. The fluctuation-induced tunneling conduction (FITC) and the hysteresis effect developing in MWCNT/EP composite are responsible for this fascinating phenomenon. In order to understand this result further, resistivity–temperature characteristic at different cooling rates was studied. The values of R e also decrease with rising the cooling rate. This paper provides an effective approach to acquire a tunable temperature sensor. [ABSTRACT FROM AUTHOR]

The degraded polycarbonate (PC) chains were successfully grafted onto the surface of silica nanoparticles (nano-SiO 2 ) by melt blending. Covalent linkage (Si–O–C bond) was formed between the degraded PC chains and nano-SiO 2 under the condition of strong shear force and high temperature. The alcoholysis between carbonate and Si–OH groups, coupled with the condensation reaction between silicon hydroxyls and hydroxyl end groups of degraded chains, mainly contributed to the formation of Si–O–C bond. As expected, the tensile strength and toughness of PC were simultaneously enhanced by incorporating functionalized SiO 2 . The improvement in tensile properties was attributed to the strong interfacial adhesion between functionalized SiO 2 and PC matrix. [ABSTRACT FROM AUTHOR]

In the present work, pre-shear was elaborately introduced into melting HDPE and then such pre-sheared melt was injection molded. The hierarchical structure and crystalline morphology of injection-molded HDPE part were investigated by using WAXD and SEM. It was found that pre-shear can enhance the formation of oriented crystals in core region of HDPE part. More interestingly, such enhancing effect becomes more remarkable if pre-shear was exerted at low temperature just slightly above the melting point of HDPE. Naturally, mechanical property was promoted due to the oriented crystals induced by pre-shear at low temperature and the narrowed orientation gap between shear region and core region. [ABSTRACT FROM AUTHOR]