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Heating the human body to maintain a relatively constant temperature is pivotal for various human functions. However, most of the current heating strategies are energy-consuming and energy-wasting and cannot cope with the complex and changing environment. Developing materials and systems that can heat the human body precisely via an efficient energy-saving approach no matter indoors/outdoors, day/night, and sunny/cloudy is highly anticipated for mitigating the growing energy crisis and global warming but is still a great challenge. Here, we demonstrate the low mid-infrared radiative (mid-IR) emissivity characteristic of Ti3C2Tx MXene and then apply it for energy-free passive radiative heating (PRH) on the human body. Our strategy is realized by simply decorating the cheap nanoporous polyethylene (nanoPE) textile with MXene. Impressively, the as-obtained 12 μm thick MXene/nanoPE textile shows a low mid-IR emissivity of 0.176 at 7-14 μm and outstanding indoor PRH performance on the human body, which enhances by 4.9 °C compared with that of traditional 576 μm thick cotton textile. Meanwhile, the MXene/nanoPE textile exhibits excellent active outdoor solar heating and indoor/outdoor Joule heating capability. The three heating modes integrated in this wearable MXene/nanoPE heating system can be switched easily or combined arbitrarily, making this thin heating system able to heat the human body precisely in various scenarios like indoors/outdoors, day/night, and sunny/cloudy, providing multiple promising and energy-saving solutions for future all-day personal precision thermal management.

Filled vulcanizates exhibit the nonlinear Payne effect under dynamic deformations at high strain amplitudes, while the underlining mechanisms are still in dispute. Herein, polydimethylsiloxane (PDMS) networks are prepared via end-linking of α,ω-vinyl-terminated PDMS chains by the thiol-ene reaction, and the influences of silica on the dynamic rheological responses are investigated. The presence of silica tends to improve the crosslinking density alongside reinforcing the network, while silica itself does not contribute to the loss factor markedly. Furthermore, silica could promote the onset strain amplitude of the Payne effect and manifest the very weak overshoot of loss modulus near the onset amplitude. By creating master curves of the Payne effect of the filled vulcanizates referenced to the end-linking networks, it is evidenced that this effect and the accompanied weak overshoot are mainly rooted in the nonlinear Rouse dynamics of the network strands.

Conductive hydrogels are capturing intensive attention for versatile applications in flexible wearable devices on account of their unique combination of softness, stretchability, conductivity and biocompatibility. However, most of the hydrogel sensors can only serve as single-type sensors to detect strain or pressure, accompanied by a limited detection range. Moreover, the poor anti-freezing performance is also a serious problem to be addressed for their practical applications. Herein, a multi-model, large range and anti-freezing hydrogel sensor was constructed from a high-mechanical and ionic conductive multi-crosslinked poly(vinyl alcohol) (M-PVA) hydrogel, which was prepared via incorporating chain entanglement interaction and complexation between Fe3+ ions and hydroxyl groups into the microcrystalline network through immersion treatment in Fe2(SO4)3 solution. The three reversible and reconstructable crosslinks within the M-PVA hydrogel worked in tandem to achieve ultra-stretchability (1120%), supercompressibility (98%), high toughness, fast self-recoverability and excellent fatigue resistance. Meanwhile, the introduction of Fe3+ and SO42- ions endowed the M-PVA hydrogel with good ionic conductivity and remarkable anti-freezing properties (-50 °C), which benefited the M-PVA hydrogel to act as a freezing-tolerant dressing. The assembled multi-model hydrogel sensor can sensitively and stably detect large range elongation (∼900%), compression (∼70%), bend and pressure (up to 4.60 MPa) concurrently, as well as various human activities including speaking, finger bending and treading behavior. Notably, the hydrogel sensor was capable of maintaining excellent mechanical flexibility and sensitive sensing capacity at low temperature. The M-PVA hydrogel is a promising flexible sensing material for versatile applications in ionic skin, motion recognition and intelligent wearable devices.

Since the first discovery of graphene in 2004, the scientific and industrial community is still finding fields to bring the excellent mechanical performance of graphene into full play. Herein, this review summarizes the recent advances in graphene and graphene derivatives toughened polymer nanocomposites, which gives full play to the unique two-dimensional nanostructure, extra specific surface area and ultrahigh mechanical properties of graphene and graphene derivatives. Using graphene and graphene derivatives as toughening modifier of polymers can not only enhance the toughness of the polymer matrix but also endow the polymer nanocomposites with enhanced strength. The preparation, performance and mechanism of graphene and graphene derivatives toughened polymer nanocomposites are highlighted in this review. The factors influencing the efficiency of graphene and graphene derivatives toughening polymers are discussed in detail. Current challenge and future direction in graphene and graphene derivatives toughened polymer nanocomposites are proposed for promoting the application of graphene in toughening polymers. This review provides a guidance for fabricating high-performance polymer/graphene nanocomposites.

Here we demonstrate a general approach to crafting a myriad of soluble octa-functionalized POSS derivatives by manipulating the sequential click reactions. After flexible modification with bio-functional groups, these uniform POSSs possess good biocompatibility, remarkable anticancer therapeutic effect and outstanding antibacterial activity in aqueous solutions. Notably, this ‘one-pot’ approach provides a simple strategy to produce customized POSS macromolecules, which may afford a novel platform for clear elucidation of more complex mechanisms and precise fabrication of high-performance biomaterials in various applications.

Toughness is an important parameter to evaluate the properties and determine the applicants of polymer/CNT nanocomposites. This study applies a rheological method to perform fast determination of the optimal mechanical properties and prediction of the conductive percolation regions of a polymer/CNT nanocomposite. The tunable mechanical and electrical properties of nylon1212/multi-walled carbon nanotube (MWCNT) nanocomposites with and without poly (ethylene-octene)-g-maleic anhydride (POE-g-MAH) are evaluated. Results indicate that three types of nanocomposites exhibit remarkable gel plateau in the dynamic rheological curves and their gel points change slightly. The introduction of POE-g-MAH can improve the notched Izod impact strength (NIIS) of nylon1212/MWCNT nanocomposites greatly. NIIS of all three nanocomposites first increase and then decrease with the MWCNT loading increasing. The gel points for three nanocomposites are related to the super-toughness points and located in the conductive percolation regions, indicating that the dynamic rheology can effectively determine the super-toughness points and predict the conductive percolation regions of nylon1212/MWCNT nanocomposites. Furthermore, the morphologies for three nanocomposites at the gel points unveil the new synergistic toughening mechanism. This study brings new insights for controlling the structures, properties and compound designs of polymer/CNT nanocomposites.

Unstable hydrogel-substrate interfaces and defunctionalization at low temperature severely restrict versatile applications of hydrogel-based systems. Herein, various chitosan-polyacrylamide double-network (CS-PAM DN) ionic hydrogels were chemically linked with diverse substrates to construct robust and anti-freezing hydrogel-substrate combination, wherein the destructible CS physical network rendered effective energy dissipation mechanism to significantly enhanced the cohesion of hydrogels and the covalent linkage between PAM network with substrate surface strongly improved the interfacial adhesion. The synergistic effects enabled the CS-PAM DN hydrogels to be tightly bonded on diverse metals and inorganics. Impressively, the hydrogel-substrate combinations were freezing tolerant to well-maintain high interfacial toughness at low temperature. Notably, due to the high toughness and conductivity of hydrogel-metal interface, the hydrogel-metal combination can be utilized as a multi-model flexible sensor to detect strain and pressure within broad temperature range. This work may provide a platform for construction and emerging application of robust, anti-freezing and stable-performance hydrogel-based systems.

The effect of silane crosslinking reaction on properties and structure of polypropylene (PP)/ethylene–octene elastomer (POE) blends had been carried out. FTIR and gel content tests confirmed the grafting and crosslinking reaction mechanism of PP/POE blends. The incorporation of POE phase enhanced the crosslinking degree and thermal stability of blends. Crystallinity of silane-crosslinked PP/POE blends decreased sharply, and the melting points change a little with the POE content increasing. The rheological curves of silane-crosslinked PP/POE blends showed an obvious “gel point”, corresponding to the dynamic crosslinking network. Solvent resistance tests suggested crosslinking had a great improvement of solvent resistance. The blends with 30% POE had good comprehensive mechanical properties. Scanning electron microscopy images exhibited that crosslinking had a great influence on the morphologies of silane-crosslinked PP/POE blends. Characterization results indicated the “gel point” acquired from rheology had some corresponding relationship with mechanical properties and solvent resistance.

It is a challenge to develop advanced elastomers with a combination of high strength, stiffness and toughness by a relatively convenient and environmentally friendly approach. Herein, we reported a facile and environmentally friendly method to prepare hybrid crosslinked nitrile butadiene rubber (NBR) comprised of covalent and ionic bonds, and this hybrid crosslinked rubber possesses comprehensively improved mechanical properties, higher crosslinking density, deformation recovery and shape memory ability. The hybrid crosslinked NBR was prepared by incorporating 2-acrylamido-2-methyl propane sulfonic acid (AMPS) and zinc oxide (ZnO) into NBR via internal milling together with dicumyl peroxide (DCP), and then vulcanization, which is a very simple and environmentally friendly method without extra procedure or treatment. The hybrid crosslinked network in NBR has randomly distributed covalent and ionic bond crosslinks, the strong covalent bonds serve as permanent crosslinks, imparting the elasticity, whereas the weak ionic bonds reversibly rupture and reform, dissipating the energy. Because of the restricting effect of ionic bonds on segmental movement, the hybrid crosslinked NBR shows higher glass transition temperature, lower loss factor peak value and longer relaxation time. By tuning the ionic bond strength via temperature, a much smaller range of linear viscoelastic region is observed for hybrid crosslinked NBR with high content of AMPS and ZnO at a relatively higher temperature, which endows the sample with shape memory ability. This design principle of incorporating ionic bonds to strengthen vulcanized NBR should be applicable to other diene rubber materials.

Two-dimensional (2D) transition metal carbides and nitrides (MXenes) have spurred great attention in many applications due to their outstanding electronic or mechanical properties. The exfoliation into single and fewer layer nanosheets of MXene is a requisite step for performance study in many cases. Herein this study aims to propose a facile and convenient liquid phase exfoliation (LPE) method to fabricate fewer-layer MXene nanosheets in large scale. The Hansen solubility parameters (HSPs) and surface tension component ratio are estimated and further applied to detect a green low-boiling-point water/acetone cosolvent for the better exfoliation of MXene. It has been found that the exfoliation efficiency is improved efficiently by matching HSPs and surface tension component ratio of MXene to that of solvents. A high concentrated MXene dispersion up to 1.727 mg/ml in the optimum composition of the water/acetone mixture which is approximately 78 and 5 times higher than that in pure acetone and water, respectively. Detailed characterization of morphology and suspension stability of exfoliated MXene are implemented which exhibit that the high quality and more stable MXene nanosheets are obtained in the suitable cosolvent. In addition, the determined HSPs and surface tension component ratio of MXene here will make a contribution to finding other new efficient solvents for MXene conveniently in specific fields.

Super-toughened polyamide 6 (PA6) material was fabricated by applying a feasible and effective method involving reactive melt blending of PA6 and residue of plasticized poly(vinyl butyral) (r-PVB)/maleated poly(ethylene-1-octene) (POE-g-MA) masterbatch, in which the multicore structure could be formed in-situ in PA6 matrix. Interfacial, rheological and morphology measurements confirmed that the POE-g-MA was encapsulated by r-PVB in PA6 matrix. The sharp brittle-ductile transition was observed at a critical interparticle distance (τc) about 0.30 μm for PA6/r-PVB/POE-g-MA blends, and the impact strength was 22–24 times higher than that of neat PA6. The flexibility of r-PVB/POE-g-MA and the strong interfacial adhesion among the three blending composition were responsible for the super toughness of PA6/r-PVB/POE-g-MA ternary blends. The DSC results suggested that the improvement of toughness was also related to the decrease in glass transition temperature (Tg) and degree of crystallinity (Xc) of PA6 matrix.

In this paper we designed greener rubber nanocomposites exhibiting high crosslinking density, and excellent mechanical and thermal properties, with a potential application in technical fields including high-strength and heat-resistance products. Herein 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc) ionic liquid was combined with silane coupling agent to formulate the nanocomposites. The impact of [EMIM]OAc on silica dispersion in a nitrile rubber (NBR) matrix was investigated by a transmission electron microscope and scanning electron microscopy. The combined use of the ionic liquid and silane in an NBR/silica system facilitates the homogeneous dispersion of the silica volume fraction (&phi, ) from 0.041 to 0.177 and enhances crosslinking density of the matrix up to three-fold in comparison with neat NBR, and also it is beneficial for solving the risks of alcohol emission and ignition during the rubber manufacturing. The introduction of ionic liquid greatly improves the mechanical strength (9.7 MPa) with respect to neat NBR vulcanizate, especially at high temperatures e.g., 100 &deg, C. Furthermore, it impacts on rheological behaviors of the nanocomposites and tends to reduce energy dissipation for the vulcanizates under large amplitude dynamic shear deformation.

Halloysite nanotubes are extensively studied natural tubular clay mineral that has many potentially important uses in different industrial fields. In this paper, the dispersion behavior of halloysite nanotubes (HNTs) in 22 solvents of different polarities was investigated by dynamic light scattering (DLS) and ultraviolet spectrophotometer (UV). The result revealed that HNTs can be dispersed in solvents with high polar and hydrogen bond component parameters, and the best dispersions were achieved in N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), ethanol (EtOH), and acetonitrile (ACN). Hansen solubility parameters (HSPs) of HNTs were approximately determined of δd = 16.8 MPa1/2, δp = 12.6 MPa1/2 and δh = 17.4 MPa1/2 based on the dispersion state tests. The HSPs of polyethylene oxide (PEO) were further estimated using the group contribution method to predict the compatibility of HNTs and PEO employing HSP theory. The SEM images of the PEO/ HNTs composites with different HNTs content showed that the HNTs were well dispersed in the PEO matrix. Meanwhile, the PEO/HNTs composites exhibited enhanced thermal stability compared to the pure PEO. The results suggested there existed good compatibility between HNTs and PEO and confirmed the usefulness of this approach.

The rheological behavior of a reactive blend system of nylon1212 with maleic anhydride grafted poly(ethylene-octene) was studied in correlating with the key mechanical parameters. Results illustrated that the “gel points” acquired from the dynamic rheological data and the “super-toughness points” of the blends have a corresponding relationship. Thus, just by simple composition designs and a small amount of samples, the super-toughness point could be conveniently determined by the dynamic rheological measurements. Furthermore, special “double network” morphology at the gel point was directly observed for the first time and the new mechanism of super-toughness has also been discussed.

An efficient catalytic system was developed for the acetalization and ketalization of carbonyl compounds with polyhydric alcohols under mild solvent-free conditions. In the presence of 0.1 mol% CoCl2 and 0.2 mol% dimethylglyoxime at 70 °C under 5 KPa pressure for 1 h, 95.3% conversion of cyclohexanone and 100% selectivity of the corresponding cyclic ketal could be obtained, where TOF reached as high as 953 h−1. It is proposed that the in situ generated planartetracoordinate cobaloxime played the key role in the catalytic cycle and was responsible for the excellent catalytic performance.

Fast and efficient determination of the optimal mechanical property of a polymer/CNT nanocomposite is crucial to develop polymer conductive nanocomposites. This work establishes a rheological approach to evaluate the super-toughness point of compatibilized high density polyethylene (HDPE)/multi-walled carbon nanotube (MWCNT) nanocomposites. Results illustrate that three types of HDPE/MWCNT nanocomposites exhibit obvious gel plateaus in the dynamic rheological curves and the gel points of nanocomposites with compatibilizer shift to the low MWCNTs loading. The super-toughness points of HDPE/MWCNT nanocomposites with compatibilizers show the correspondence with the gel points acquired from the rheological data, indicating that dynamic rheology is an effective way to determine the super-toughness points of HDPE/MWCNT nanocomposites with compatibilizers. Furthermore, unique network structure at the gel points is directly observed and the new mechanism of toughness is proposed. This study provides new insights for effective control of the structures and properties of polymer/CNT nanocomposites.

With the miniaturized and high-frequency development in electronic products, polymeric films synchronously with high electromagnetic interference (EMI) shielding effectiveness (SE) and thermal conductivity (TC) are urgently needed. In this work, poly (vinyl alcohol)/transition metal carbide (PVA/MXene) films featured with alternating multilayered structure were fabricated through multilayered casting. The continuous MXene layer provided a compact network for conducting heat and electron, endowing the multilayered film with excellent EMI SE and TC synchronously. In particular, the 27-μm-thick PVA/MXene multilayered film (containing 19.5 wt% MXene in total) exhibited an electrical conductivity of 716 S/m, a maximum EMI SE of 44.4 dB and a specific EMI SE (SSEt) of 9343 dB cm2 g−1. Meanwhile, the multilayered film showed a high in-plane TC of 4.57 W/mK, enhanced by almost 23-fold compared with that of neat PVA. Moreover, the multilayered architecture endowed the film with remarkable anti-dripping performance. This work provides a novel and feasible strategy for fabricating flame-retardant polymeric thermal conductive and EMI shielding films, which will have enormous prospect in advanced electrical devices.

MXenes, as a novel family of two-dimensional metal carbides/nitrides, have attracted enormous attention in many fields including polymer composite materials. However, the melt-dripping phenomenon in most polymer matrices great limits the application of polymer composites. So far, the anti-dripping performance of polymer/MXene composites has rarely been reported. Herein, the potential of MXene on improving the anti-dripping performance of polymers was firstly explored based on three different polymer/MXene composites prepared via solution blending and dip-coating, respectively. The results showed that MXene endowed the polymer matrices with excellent anti-dripping performance and thermal stability. Corresponding mechanism for anti-dripping performance of polymer/MXene composites was investigated deeply. This work will open the door of MXene in polymer composites toward remarkable anti-dripping performance, which can broaden the application of MXene in polymer composites greatly.

Highly thermal conductive polymer composites synchronously with excellent dielectric and mechanical properties are highly desired in electronic devices. In this work, largely enhanced thermal conductivity (TC), dielectric constant and mechanical property were synchronously realized in polycarbonate (PC) matrix via incorporating boron nitride (BN) together with few graphene nanoplatelets (GnPs) and carbon nanotubes (CNTs). Significantly reduced interfacial thermal resistance between BN and matrix in PC/BN@GnP@CNT composites was the main reason contributed to the largely enhanced TC. By synchronously adding 20 wt% BN (BN-20), 1 wt% GnPs and 1 wt% CNTs, the TC of PC/BN-20@GnP@CNT composites reached up to 1.42 W/mK, enhanced by 647% and 103% compared with that of neat PC and PC/BN-20 composites, respectively. The dielectric constant of PC/BN-20@GnP@CNT reached up to 177 at 100 Hz (enhanced by ~50-fold compared with PC/BN-20) while the dielectric loss was kept at a low level. Compared with PC/BN-20, the yield strength, elongation at break, fracture toughness and notched impact strength of PC/BN-20@GnP@CNT were enhanced by 42%, 103%, 146% and 8%, respectively. Meanwhile, PC/BN/GnP@CNT composites showed significantly reduced ignitability and remarkable anti-dripping performance. This work promotes an effective, feasible strategy for fabricating dielectric thermal conductive polymer composites with excellent mechanical and anti-dripping performance.

The effects of solvent casting parameters on the molecular dynamics of poly(methyl methacrylate)/poly(styrene-co-maleic anhydride) (PMMA/SMA) blend films was investigated using broadband dielectric spectroscopy. Through changing the solvent type and solution concentration, blend film samples with different entanglement intensity were prepared, and they can significantly affect the glass transition temperature ( T g ) and segmental dynamics of the films. In films cast from a methyl ethyl ketone (MEK) solution at various concentrations, T g and relaxation time ( τ max ) increase with increasing solution concentration due to an increased entanglement density, decreased molecular mobility and entanglement recovery. No obvious distribution broadening is observed due to the unchanged heterogeneous dynamics. In the case of films cast from chloroform, MEK and tetrahydrofuran solution, T g and τ max of the resultant films are hardly affected, while T g and τ max of films cast from a N, N-Dimethylformamide (DMF) solution are much higher than the other three due to a higher entanglement degree and strong interaction contributions. Moreover, the poor dissolving capacity of DMF may result in more heterogeneous dynamics and subsequently a larger dc conductivity process and broader and more symmetric α -relaxation spectra. Neither the dynamics nor the distribution width of the subglass relaxation processes is affected by the casting solvent or solution concentration, indicating little change in the local environment of the segments.

In situ microfibrillar composites (PP/mPA66) of modified polyamide66 (mPA66) with polypropylene (PP) were prepared by using a “post-compatibilization” technique. The mPA66 was firstly obtained by reactive extrusion of PA66 resin with a specially designed compatibilizer, which was then blended with PP through extrusion combined with a hot stretching and subsequently quenching process. The PP/mPA66 in situ microfibrillar composites were comparatively studied with simply blended samples of PP/PA66 that were prepared by blending PA66 and PP together with (or without) the same compatibilizer through extrusion. PA66-g-PP (and/or elastomers) graft copolymer formation in mPA66 was identified by dissolution test and infrared spectroscopy measurement, the compatibilizer is unevenly dispersed with large domains in PA66 as observed by scanning electron microscope (SEM). In PP/mPA66 composites, the in situ generated PA66 microfibrils have a rather nonuniform diameter distribution and a very rough surface. SEM observations for the fractured surface illustrated that PP/mPA66 composites have structural characteristics of stronger adhesion and moderate flexibility of the interface. Enhanced compatibilization between the PA66 microfibrils with the PP matrix resulted in improved mechanical properties of the PP/mPA66 composites. With optimized composition, the PP/mPA66 composite has notched Izod impact strength, flexural modulus, and tensile yield stress of 1.49, 1.16, and 0.99 times as those of the neat PP, respectively. Such enhanced mechanical properties balance and improved interface adhesion were not found in the simply blended samples of PP/PA66 with or without the specially designed compatibilizer. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Studies on the morphologies and rheological characteristics of two styrene–butadiene–maleic anhydride block copolymers (SBMa) have been performed. The transmission electron microscopy micrographs show that the morphologies of SBMa change from matrix–island structure to co-continuous structure. Curves for dynamic modulus varied with frequency (ω) show obvious solid-like behavior in the low ω region, which is typical for ordered block copolymers or networked materials. Van Gurp–Palmen plots have been used to exploit the thermorheological complexity of two copolymers. The master curves of two copolymers have been acquired through time–temperature superposition principle, and the plateau modulus (G) have been obtained from G′ at ω, where the loss tangent (tan δ) approaches a minimum. Meanwhile, Williams–Landel–Ferry equation has been used to evaluate the free volume parameters. The relaxation time spectra of two copolymers have been calculated and fitted with modified Baumgaertel–Schausberger–Winter model. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Uniform monodisperse nanospheres of tetra-kis(4-methoxylphenyl) porphynatemanganese (III) chloride [MnIII(TMOPP)Cl] of about 200 nm have been synthesized through a facile surfactant-assisted reprecipitation method at room temperature. Scanning electron microscopy, transmission electron microscope, infrared spectrum, ultraviolet–visible spectrum, and elemental analysis were adopted to characterize the as-prepared metalloporphyrin nanostructures. The influence factors in the reaction to the sizes and morphologies of porphyrin nanoparticles were discussed. The sizes of porphyrin nanoparticles were affected mainly by the porphyrin concentration and only monodisperse nanoshperes with high uniformity in sizes and shapes can self-assemble to form order two-dimensional superstructures.

BACKGROUND: Polyamides, or nylons, are an attractive class of engineering polymers due to their excellent strength and stiffness, low friction and chemical and wear resistance. However, they are highly notch-sensitive, i.e. they are often ductile in the un-notched state, but fail in a brittle manner when notched. A super-tough nylon 1212 was prepared by blending nylon 1212 with ethylene propylene diene monomer (EPDM) grafted with maleic anhydride (MA). The morphologies of Izod impact fracture surfaces as well as xylene-etched surfaces of the nylon were thoroughly investigated using scanning electron microscopy (SEM). RESULTS: The fracture morphology and the impact strength of the nylon 1212 blends are very well correlated. The impact fracture surface of the blends exhibits certain characteristic features, such as the observation of fiber-like sticks when etched with boiling xylene, formed during the impact fracture process. SEM images of xylene-etched surfaces as well as the results of X-ray energy dispersive spectroscopy suggest that the successful toughening of nylon 1212 with EPDM-graft-MA is due to the reaction between the anhydride of EPDM-graft-MA and the amine end-groups of nylon 1212, leading to the formation of a homogenous graft copolymer system. CONCLUSION: The copolymer system, acting as a surfactant, reduces the interfacial tension between nylon 1212 and EPDM-graft-MA and produces a highly compatible super-tough nylon 1212. Copyright © 2008 Society of Chemical Industry

Studies on the gelation behaviors of the reactive blends of nylon1212 and functional elastomer were carried out. The results show that the curves of the storage modulus(G′)–frequency (ω) exhibit a gel plateau in the low ω region, and the transition from liquid-like to solid-like viscoelastic behaviors emerges with the concentration of SEBS-g-MA increasing. There exist the gelation behaviors in the blending process similar to those of crosslinking polymer. Based on Winter’s method, the gel point of blends is determined to be, φg = 17.45 wt%, and the corresponding value of tanδ is 1.44. The gel index n calculated is 0.61 and the gel strength Sg is 1.08 × 104 Pa s0.61. However, the non-reactive blends of nylon1212 and elastomer have no emergence of gelation behaviors. The morphology analysis shows that the gel point for the reactive blends is a threshold of cocontinuous morphology, and morphology analysis can also be a method to determine the gel point.

Studies on the viscoelastic behavior of styrene-[ethylene-(ethylene-propylene)]-styrene block copolymer (SEEPS) were carried out, and some characteristic viscoelastic parameters were calculated. The longest relaxation time τmax was obtained through simulating the relaxation spectrum on the basis of a modifiedBaumgaertel-Schausberger-Winter (mBSW) model. The results revealed that there exists a “second plateau” in the low frequency region of the master curves. The reason for this phenomenon is attributed to the entanglement of macromolecular chains. It is suggested that the hard blocks, polystyrene, act as entanglement points, resulting in a topology restraint to the movement of macro-molecular chains. Meanwhile, it is found that the horizontal shift factors (aT) vs temperature in the master curve could be fitted to theWilliams-Landel-Ferry (WLF) equation andArrhenius equation respectively and the flow activation energy (Ea) is 127.88 kJ/mol. In addition, the plateau modulus (GN 0 and entanglement molecule weight (Me) were calculated.

In the recent decades, there has been an increasing interest in preparing novel polymeric blending materials with combined and additional characteristics of each component. Having a relatively high modulus, toughness and strength, low creep, and good temperature resistance, nylons have been widely applied in the automotive industry, machinery, electronic equipment, and military applications [1]. It is well-known that blends consisting of nylon and elastomer possess excellent toughness; however, due to its highly polar amide end-groups, nylon is incompatible with elastomer. In general, it is believed that functionalization of the elastomer is a preferred approach to enhance the interfacial properties between these polymers. Research concerning nylon/functionalized elastomer blends has mostly focused on the aspects of mechanical and thermal properties. To our knowledge, only a few reports have dealt with dynamic rheological behavior of their melts [2–4]. The rheological measurements not only give much useful information for material moulding and processing, but also is an important way to characterize the structure and properties of polymer materials [5, 6]. The aim of this article is to study the influence of the graft reaction between nylon1212 and SEBS-gMA on dynamic rheological behavior and morphology of their blends. Nylon1212 (melt-flow index = 22.43 g/min) used here was obtained from Shandong Dongchen Engineering Plastic Co., Ltd., China. The elastomer, a triblock copolymer styrene-b-(ethylene-co-butylene)-b-styrene (SEBS 4033) was supplied by the Yuyao Huiju Polymer Co., Ltd. China. The maleated triblock copolymer styrene-b-(ethylene-co-butylenes)-b-styrene (SEBS-gMA) was supplied by Yuyao Yongcheng Engineering plastics Co., Ltd., China. The grafting ratio of maleic anhydride is 1.84 wt%. Both SEBS and SEBSg-MA consist of 30 wt% polystyrene end-blocks. The nylon1212/SEBS blends and nylon1212/SEBS-g-MA blends including 1 wt% antioxidant (1010) were prepared in a corotating twin-screw extruder (PRISM TES 16TC, UK) at 210 ◦C. All the samples were compression-moulded into disks of 25 mm in diameter and 1.2 mm in thickness at 180 ◦C, 50 MPa. Melt rheological tests were conducted in an ARES Rheometer

A reactive, intumescent, halogen-free flame retardant, 2-({9-[(4,6-diamino-1,3,5-triazin-2-yl)amino]-3,9-dioxido-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecan-3-yl}oxy)ethyl methacrylate (EADP), was synthesized through a simple three-step reaction from phosphorus oxychloride, pentaerythritol, hydroxyethyl methacrylate, and melamine. EADP exhibited excellent thermal stability and char-forming ability, as revealed by thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The TGA results show that the temperature at 5% weight loss was 297.8°C and the char yield at 700°C was 51.75%. SEM observation revealed that the char showed a continuous and compact surface and a cellular inner structure with different sizes. Composite of polypropylene (PP) with a 25 wt % addition of EADP (PP/EADP25) passed the UL-94 V-0 rating and showed a limiting oxygen index value of 31.5. Compared with those of neat PP, the flexural strength and modulus values of PP/EADP25 were somewhat improved, the tensile strength was basically unchanged, and the notched Izod impact strength was slightly decreased. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40054.