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Herein, inorganic silicon dioxide (SiO2) nanoparticles are deposited on the surface of continuous basalt fibers (CBFs) to enhance the interfacial interactions between CBFs and epoxy matrix (EP) and the tensile strength of composites. According to results from scanning electron microscopy and atomic force microscopy, the surface morphology of CBFs changes from smooth to rough with the increase of SiO2 deposition content. The rough surface plays a role of chock to make CBFs implant into the EP better, offering strong mechanical engagement effect to the interface between CBFs and EP. Therefore, the interfacial shear strength (IFSS) between CBFs and EP and the tensile strength of composites both increase. However, depositing excessive SiO2 nanoparticles also brings some porous structures on CBFs surface, becoming defects and stress concentration points to weaken the IFSS and the tensile strength of composites. Finally, a comparison between grafting organic aliphatic chains and depositing inorganic rigid nanoparticles about their effects on the surface roughness of modified CBFs and the interfacial interactions between modified fibers and matrix is carried out to clarify the reinforcing mechanisms of interfacial adhesion and the tensile strength of composites.

Lithium metal is deemed as an ideal anode material in lithium-ion batteries because of its ultrahigh theoretical specific capacity and the lowest redox potential. However, the rapid capacity attenuation and inferior security resulting from the dendritic lithium growth severely limit its commercialization. Herein a novel hybrid gel polymer electrolyte (GPE) based on electrospun lithium sulfonated polyoxadiazole (Li-SPOD) nanofibrous membrane swelled by lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) ether liquid electrolyte is proposed to address the issue of lithium dendrites. The Li-SPOD membrane synthesized by a simple one-pot method exhibits excellent mechanical strength and thermal resistance due to its high molecular weight and rigid backbone. The electron-withdrawing oxadiazole ring and oxadiazole ring-Li+ complex, and N, O heteroatoms with lone pairs of electrons in Li-SPOD macromolecular chains facilitate the dissociation of -SO3Li group and Li+ transference. The hybrid Li-SPOD GPE exhibits both a high lithium-ion transference number (0.64) and high ionic conductivity (2.03 mS/cm) as well as superior interfacial compacity with lithium anodes. The LiFePO4-Li cell using this novel GPE can operate steadily at 2 C for 300 cycles, remaining a high discharge capacity of 125 mAh/g and dendrite-free anode. Remarkable performance improvements for the Li-Li and Cu-Li cells are also presented.

Traditional polyolefin separators used in lithium-ion batteries (LIBs) are seriously limited by the issues of inferior security and poor electrolyte wettability. Most of the very promising candidat...

Among the various polymer fibers available, polypropylene (PP) fibers are often used to improve the impermeability, impact resistance, anti-wear and crack resistance of concrete. In order to improv...

The inner and surface morphology of the polyphenylene sulfide membrane could be well optimized by controlling the phase separation during the thermally induced phase separation process.

Two kinds of thermotropic liquid crystalline polyesters (TLCP) with different chemical structures were used as flow modifiers during the melt spinning of poly (ether ether ketone). One of T...

The effects of ozone aging on the structure and related properties of poly(hexamethylene adipamide) (PA66), poly(p-phenylene dodecanediamine) (PA12T), poly(m-phenylene isophthalamide) (PMIA), and p...

In this study, a series of immiscible polymer blend fibers with polypropylene (PP) and polyvinyl alcohol (PVA) was obtained by a melt spinning process, and two different draw ratios were attempted. Efforts were made to obtain the porous PP fibers by removing the water-soluble PVA phase. The thermal properties of the blends were tested by thermogravimetric analysis and differential scanning calorimetry. The blends showed excellent thermal stability and differentiated fractionated crystallization behaviors of PP. The melt flow indexes of the blends were evaluated, exhibiting a higher fluidity than that of the neat polymers. Among the possible candidates for the spinning process, only the PP70–PVA30 had suitable spinnability, for which the draw ratio reached 3. The morphology of the fibers was investigated by selective extraction experiment and scanning electron microscopy, as well as wide-angle X-ray diffraction. The biphasic morphology and the crystallization behaviors varied according to the PVA content. Furthermore, the mechanical properties of the multifilament fibers were studied via tensile testing and dynamical mechanical analysis. The 70/30 weight ratio (PP/PVA) was the most suitable for producing biphasic fibers with a high degree of accessibility in PVA and mechanical properties that increase with the increase in the drawing ratio. The feasibility of fabric knitting was checked, and the mechanical properties and air permeability of the obtained textile structure were also evaluated.

A novel intumescent flame retardant (IFR) agent designated as Dohor-6000A has been used to prepare halogen-free flame retardant polypropylene (PP) fibers via melting spinning. Before being blended with PP resin, a surface modification of Dohor-6000A was carried out to improve its compatibility with the PP matrix. The rheological behavior of flame retardant Dohor-6000A/PP resin, the structure, morphology, mechanical properties, flammability of the Dohor-6000A/PP fibers were studied in detail, as well as the action mode of flame retardant. X-ray diffraction (XRD) showed that the addition of Dohor-6000A did not damage the crystal as well as the orientation structure of PP matrix, which was helpful to the maintenance of mechanical properties. The presence of the IFR significantly improved the flame retardant performance and thermal stability of PP fibers. When the content of Dohor-6000A reached 25%, the fibers displayed a limiting oxygen index (LOI) value of 29.1% and good melt-drop resistance. Moreover, the peak heat release rate (PHRR) and total heat release (THR) from microscale combustion colorimetry (MCC) tests were decreased by 26.0% and 16.0% in comparison with the same conditions for pure PP fibers. In the condensed phase, the IFR promoted a carbonization process and promoted the formation of a glassy or stable foam protective layer on the surface of the polymer matrix. In addition, the IFR decomposed endothermically to release of non-combustible gases such as NH3 and CO2 which dilutes the combustible gases in the combustion zone.

Extracting and fusing part features have become the key of fined-grained image recognition. Recently, Non-local (NL) module has shown excellent improvement in image recognition. However, it lacks the mechanism to model the interactions between multi-scale part features, which is vital for fine-grained recognition. In this paper, we propose a novel cross-layer non-local (CNL) module to associate multi-scale receptive fields by two operations. First, CNL computes correlations between features of a query layer and all response layers. Second, all response features are weighted according to the correlations and are added to the query features. Due to the interactions of cross-layer features, our model builds spatial dependencies among multi-level layers and learns more discriminative features. In addition, we can reduce the aggregation cost if we set low-dimensional deep layer as query layer. Experiments are conducted to show our model achieves or surpasses state-of-the-art results on three benchmark datasets of fine-grained classification. Our codes can be found at github.com/FouriYe/CNL-ICIP2020., Accepted by ICIP2020

In order to improve the flame retardance of aromatic polyoxadiazole (p-POD) fiber, a series of phosphorus-containing PODs (pho-POD) were synthesized by introducing triaryl phosphine oxide (TPO) units into the main chains of p-POD using hydrazine sulfate, terephthalic acid and bis(p-carboxy)phenyl phosphine oxide (BCPPO) as monomers, and then halogen-free flame resistant pho-POD fibers were obtained from wet spinning. The structure and properties of the pho-POD fibers were characterized and measured in detail using the methods of wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), the limiting oxygen index (LOI), oxygen bomb calorimeter, Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GC/MS) etc. The results show that the introduction of TPO units resulted in the weakening of the crystallization ability, the formation of the poriferous and lax interior structure, the slight decrease in the thermal stability and mechanical properties of the POD fibers. However, the value of LOI obviously increased from 28% to 35%, and the gross heat of combustion (GHC) decreased from 19.72 MJ kg−1 to 17.84 MJ kg−1 with the increase in the content of the BCPPO. Moreover, the combustion residue of pho-POD fiber revealed a smooth, dense and non-porous carbon layer, which could effectively play a role of oxygen barrier and enhance the flame resistance. From the above results, it can be concluded that the flame resistance of the POD fiber could be improved significantly after introducing the TPO unit. The results of Py-GC/MS illustrate that the TPO unit of pho-POD could inhibit the production of volatile products, which could be confirmed that the mechanism of enhancing the flame retardancy by introducing TPO units was mainly the flame retardation of the condensed phase.

The interfacial strength between reinforced fiber and a polymeric matrix is a critical factor for determining the mechanical properties of composites. Here, grafting multi-walled carbon nanotubes (MWCNTs) onto plain weave glass fabric (PWGF) is introduced to improve the interfacial strength of PWGF reinforced polyphenylene sulfide (PPS) composites. Firstly, MWCNTs-g-PWGF is prepared by grafting oxidized MWCNTs onto functionalized PWGF, and then the MWCNTs-g-PWGF/PPS composite laminates are fabricated by an opening hot pressing process. Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) confirm that the MWCNTs are successfully grafted onto PWGF by chemical linkage. The interfacial morphologies are characterized by scanning electron microscopy (SEM), which reveals a good interfacial compatibility in MWCNTs-g-PWGF/PPS composites. The mechanical properties of MWCNTs-g-PWGF/PPS composites are also characterized by dynamic mechanical analysis (DMA) and universal tensile or bending testing. According to the results, the present method of manufacturing MWCNTs-g-PWGF/PPS composites produces an increase of almost 126% in tensile strength and a significant enhancement of nearly 155% in the bending strength compared with PWGF/PPS composites. The notable increase in the glass transition temperature of MWCNTs-g-PWGF/PPS composites also reflects the remarkable improvement in interfacial strength of the composites.

Shape memory polymers are stimulus responsive smart materials that can be applied in several forms such as films, fibers, and foams for a wide range of applications. Novel stress-memory behavior at a fiber level is yet to be uncovered, which would be favorable to control stress in the broad horizon of smart materials for numerous functions. In this work, a semi-crystalline segmented polyurethane was synthesized to prepare filaments/fibres and films. A rational experimental design was established and the stress-memory behavior of both the films and filaments was systematically studied for comparison. Tensile stress-memory programming was performed at three strain levels (20%, 40%, and 60%) to record the memory stress response as a function of temperature with time. The characterization of the thermal and mechanical properties of the stress-memory programmed specimens has objectively proven the reason behind the higher stress response in the filaments than in the films. Melt spinning has induced perfect crystallization with ordered polymer packing and enabled maximum memory stress to be retrieved in the filaments. The evolution of memory stress follows a linear trend with an increase in strain and temperature (r2 = 0.91–1). In addition, pressure related studies were also carried out for smart filament integrative fabrics to realize stress-memory behavior. This unprecedented and novel approach of unveiling the memory behavior specifically at the filament level will enable material scientists to comprehend the fundamental aspects for precise optimization and control of memory stress in smart structures for applications such as compression stockings that require stimuli responsive force.

The formalized polyvinyl alcohol fibers (PVF fibers) were grafted with acrylic acids after being activated in dilute potassium permanganate solution, and then the grafted PVF fibers (PVF-g-AA fibers) were reacted with melamine formaldehyde (MF) oligomer solution to form flame-retardant coatings on their surface. The coated PVF fibers (PVF-g-AAMF fibers) were further treated with copper sulfate solution for absorbing copper ions to promote their flame retardant performance. The structure of the fibers was characterized by FTIR spectra and SEM photos. The flame-retardant performance of the fibers was evaluated by limiting oxygen index (LOI) and microcalorimeter tests (MCC tests). It is found that MF coatings effectively improved the flame resistance of PVF fibers, but the flame retardant efficiency was not satisfactory. Copper ions have an obvious synergistic effect on the flame resistance of the fibers. SEM photos of char residues, results of TGA and TG-IR revealed that the flame retardance of MF coatings is mainly due to gaseous phase.The effect of copper ions on the thermal decomposition of MF resins was analyzed with pyrolysis-gas chronograms-mass spectrometry (PyGC-MS), and it is found that copper ions catalyzed the thermal decomposition of MF resins, which synchronized the decomposition of MF resins and PVF fibers. Copper ions are also effective in improving the char residues of PVF-g-AAMF fibers. The flame resistance of the fibers was improved dramatically by the synergistic effect between the grafted MF resin and the copper ions.

Polyethylene glycols (PEG) with relative molecular weights of 2,000, 10,000, 20,000, and 50,000 were grafted onto the surface of Poly (ether ether ketone) (PEEK)hollow fiber membranes respectively by UV irradiation grafting methods. The surface morphology, pore structure, and filtration performance of the PEEK and PEEK-g-PEG membranes were investigated in detail. Moreover, the bovine serum protein(BSA)was used as a model foulant to characterize the antifouling performance of the membrane. The effects of grafting density and grafting chain length on membrane permeability and antifouling performance were explored. The results of surface morphology showed that after grafting polyethylene glycol, there was no significant decrease of the surface porosity. When the relative molecular weight of PEG is 2000, the normalized water flux of the PEEK-g-PEG2000 membrane is increased to 3.38, but the flux recovery rate is only 79.9 %; when the molecular weight of PEG is 50,000, the flux recovery rate of the PEEK-g-PEG50000 membrane is 99.2 %, but the normalized water flux decreased to 0.73. Therefore, the increase of hydrophilicity can improve the permeability of the membrane, but the long grafting chains easily plugs the membrane pores and reduces the permeability of the membrane. The research found that the grafting density and grafting chain length have different mechanisms of action to prevent the adsorption of foulants to the polymer matrix. The antifouling performance of PEEK membrane can be effectively improved by regulating the grafting density and grafting chain length.

An in-situ polymerization combined with chemical grafting modification method for preparing Poly(vinyl alcohol)-grafted graphene oxide/Poly(vinyl alcohol) (PVA-g-GO/PVA) nanocomposites was reported. Firstly, Poly(vinyl acetate)-grafted graphene oxide/Poly(vinyl acetate) nanocomposites were prepared, and then the PVA-g-GO/PVA nanocomposites could be obtained through alcoholysis reaction. X-ray photoelectron spectrometer and fourier-transform infrared spectrometer confirmed that the PVAc or PVA chains were successfully grafted to GO sheets during in-situ polymerization and alcoholysis. And the results from transmission electron microscopy, scanning electron microscopy and X-ray diffraction showed that the well compatibility and homogenous dispersion of PVA-g-GO in PVA matrix could be achieved. Differential scanning calorimetric, thermogravimetry analysis and tensile test were employed to study the thermal and mechanical properties of the PVA-g-GO/PVA nanocomposites. The results indicated that a 53% improvement of tensile strength and a 36% improvement of Young’s modulus were achieved by addition of 0.5 wt% of GO sheets. And the glass transition temperature of PVA-g-GO/PVA nanocomposites was increased, and their thermal stability and crystallization degree were both decreased. Due to well dispersion of fillers and strong interfacial interactions at the filler-matrix interface, in-situ polymerization combined with chemical grafting modification was a good choice to prepare graphene/PVA nanocomposite with excellent mechanical properties.

A type of quick water-responsive shape memory hybrids is fabricated by introducing cellulose nanofibrous mats as the filler in a polymeric matrix. Cellulose nanofibrous mats are obtained through hydrolyzing electrospun cellulose acetate (CA) nanofibers, then casted in thermoplastic polyurethane (TPU) solution to form the hybrids. The quick shape memory behavior of the formed hybrids is demonstrated using dynamic mechanical analysis (DMA) and stress–strain cyclic test. According to a predetermined protocol, the hybrids present desirable shape fixation and recovery, and the elastic modulus (E′) is shown to be responsive promptly and reversibly against drying and wetting cycle. Shape memory mechanism of the hybrids involves the reversible and competitive hydrogen bonds within cellulose before and after water immersion as well as the entropy elasticity of the TPU matrix. This study can pave a way to design novel smart materials by facile methods through incorporating natural nanomaterials as water sensitive fillers. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016

Various proportions of 4,4′-oxybisbenzoic acid (OBBA) were incorporated to obtain the spinning solution of sulfonated polyoxadiazole (SPOD) copolymer through copolymerization in oleum. And the sulfonated fibers were prepared from the solution by using wet spinning approaches. The chemical structures of the fibers were characterized using Fourier transform infrared spectroscopy (FTIR) and elemental analyzer. The results indicated that sulfo groups were successfully introduced into the macromolecular chain. And the flame retardancy of the SPOD fibers was evaluated by limiting oxygen index, UL-94 and microscale combustion calorimeter tests, showing that flame-retardant properties could be significantly enhanced. And the thermal decomposition and flame-retardant mechanism were studied through various analytical methods. And thermogravimetric (TG) analyzer and scanning electron microscope results showed that the incorporation of OBBA would help fibers form more compact carbon residue. X-ray photoelectron spectroscopy and TG-FTIR results revealed that sulfur element increased carbon residue rate in the condensed phase and some converted into SO2 in the gas phase. Py-GC/MS results showed that thermal decomposition happened at oxadiazole rings and the introduction of OBBA did not alter the decomposition mechanism of POD essentially.

Poly (ether ether ketone) (PEEK) ultrafiltration membrane was modified with 2-hydroxylethyl acrylate (HEA) as a hydrophilic monomer through light-initiated grafting polymerization to improve its permeability and antifouling property. The effects of monomer concentration and irradiation time on the surface’s chemical structure and morphology, degree of grafting (DG), surface hydrophilicity and pore volume of the membranes were systematically investigated; meanwhile, the antifouling property were characterized and analyzed using bovine serum albumin (BSA) as a model foulant. The results indicate that the DG and hydrophilicity of the membrane surface are enhanced with the increase of either monomer concentration or irradiation time. The water flux of modified membrane using 0.3 mol/L HEA and 20 min irradiation time is 1.52 times that of unmodified membrane, and the irreversible fouling decreases from 51 % to 10.9 %. In this work, the graft chain length and graft density are considered to be controlled by the factors of monomer concentration and irradiation time, respectively. Compared with increasing the graft density, the increase of the graft chain length is more easily to lead to a decrease in membrane permeability. Meanwhile, the long chain length is more important than the high graft density to achieve excellent antifouling performance.

To improve the flame resistance of polyvinyl alcohol (PVA) fibers, the well-designed permanent flame-retardant coatings were introduced on the surface of PVA fibers. Acrylonitrile (AN) was firstly grafted on the PVA fiber surface and then the grafted fibers (PVA-g-AN fibers) were reacted with hydrazine hydrate and copper sulfate solution to form the coatings with flame retardant performance. The structure of the fibers was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The flame-retardant performance of the fibers was evaluated by limiting oxygen index (LOI) and micro calorimeter (MCC) tests. It was found that the coatings were effective in improving the flame resistance of PVA fibers. SEM photos of char residues and the results of the TG-IR technique revealed that flame retardance is mainly provided through the barrier action of the coatings with the partial effect of gaseous phase.

A kind of flame-retardant polyacrylonitrile fiber was prepared successfully by the modification with diethylenetriamine and zinc ions (Zn2+). The chemical, aggregation and morphological structures of the aminated fibers were studied by Fourier transform infrared (FTIR) spectra, X-ray diffraction and scanning electron microscope (SEM). Meanwhile, mechanical and adsorption properties were investigated by a tensile tester and atomic absorption spectrometry. The flame retardancy of the modified fibers was significantly improved after modification. And the thermal degradation behaviors and flame retardancy mechanisms were studied in detail. The microscale combustion calorimeter and TG-FTIR results showed that the modified fibers decomposed less combustible gases and more non-combustible gases comparing the original fibers. And thermogravimetric analysis and SEM tests revealed that Zn2+ would stabilize the main chains and promote formation of compact char layers. And differential scanning calorimetry tests indicated that Zn2+ would inhibit the cyclization exothermic process. Results showed that the combination of gas phase and condensed phase mechanisms optimized the flame retardancy performance.

The polyvinyl alcohol (PVA) as-spun fibers were prepared by dry-wet gel spinning, with dimethylsulfoxide (DMSO) as solvent and methanol as the cooling medium. The rheological properties of spinning solutions, matter exchanges, sonic orientation factor and entanglement of PVA as-spun fibers were investigated. Solution with lower PVA content at lower temperature has a same viscosity with the more concentrated solution at higher temperature. Solution with lower concentration has a higher G′ and a lower Tan δ, which leads to a lower sonic orientation factor for the fiber. The calculating results from the optical microscope show that solution with lower PVA content loses less DMSO due to the weaker gel ability and the possible phase separation during the coagulation. Moreover, solution more closed to the gel point bounds more DMSO, which makes the DMSO exchange difficult to process. The entanglement in the as-spun fiber decreases with the decreasing PVA content in the solution. Suitable crystallization and entanglement can obtain fibers with higher strength.

Poly(vinyl alcohol)-grafted Graphene oxide (PVA-g-GO) as novel nanofillers were used to reinforce poly(vinyl alcohol) (PVA) composite fibers via simple wet spinning to promote homogeneous dispersion of reinforcing nanofillers as well as strengthen interfacial adhesion between nanofillers and matrix. Then the impact of these PVA chains grafted above GO sheets on the compatibility and dispersion of PVA-g-GO sheets in PVA fiber, the interfacial adhesion between nanofillers and matrix and the structure as well as property of PVA-g-GO/PVA fibers were studied systematically via characterizing morphology, aggregation structure and mechanical property of these composite fibers. These results showed that not only well dispersion and compatibility of PVA-g-GO sheets in composite fibers could be achieved, but also obvious enhancement in interfacial adhesion between nanofillers and matrix. Meanwhile, significant reinforcement in tensile strength and initial modulus of these composite fibers could also be obtained. Compared with neat PVA drawn fiber, tensile strength and initial modulus of these composite drawn fibers could increase by 39% and 69% with addition of 0.60 wt% of PVA-g-GO sheets, respectively. On the one hand, crystallization and orientation degree of these composite fibers could be improved because of the template-oriented effect of PVA-g-GO sheets during hot drawing. On the other hand, efficient load transfer between matrix and nanofillers in composite drawn fibers could be achieved easily because of the strong interfacial adhesion between nanofillers and matrix. These were also two main reasons for the obvious improvement in tensile strength and initial modulus of composite drawn fibers.

Polyoxymethylene (POM) fiber was produced by melt spinning with a high take-up speed, which imposed a strong flow field. An unexpected formation of a shish-kebab morphology with multiple shish of POM fibers was reported for the first time. This morphology is a large-scale shish kebab with a diameter of 10.5 µm. Further orientation of the POM fiber was obtained by hot stretching twice at 160°C. Two crystalline morphology evolution processes were also observed: (i) the process from the large-scale shish-kebab to the deformed small shish-kebab and (ii) the process from the deformed small shish-kebab to the perfect whiskers. Compared with the melt spinning fiber, fiber tensile strength with first and second hot stretching increased by 976% and 1705%, respectively. The crystalline melting behavior of fibers significantly changes after the first and second hot stretching. The flow field induces a large number of extended chain crystals. Copyright © 2014 John Wiley & Sons, Ltd.

Poly(ether ether ketone) (PEEK) hollow fiber membranes were successfully prepared from miscible blends of PEEK and polyetherimide (PEI) via thermally-induced phase separation (TIPS) with subsequent extraction of the PEI diluent. The phase structure evolution, extraction kinetics, membrane morphology, pore size distribution and permeability for the hollow fiber membrane were studied in detail. Extraction experiments, differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMA) studies showed that the heat treatment had a significant influence on the two-phase structure of PEEK/PEI, and that it was controlled by the crystallization kinetic of PEEK and the diffusion kinetic of PEI. As the annealing temperature increased, the controlling factor of the phase separation changed from PEEK crystallization to PEI diffusion, and the main distribution of the amorphous PEI chains were changed from the interlamellar region to the interfibrillar or interspherulitic regions of PEEK crystallization. When the annealing temperature increased from 240 &deg, C to 280 &deg, C, the extracted amount of PEI increased from 85.19 to 96.24 wt %, and the pore diameter of PEEK membrane increased from 10.59 to 37.85 nm, while the surface area of the PEEK membrane decreased from 111.9 to 83.69 m2/g. Moreover, the water flux of the PEEK hollow fiber membranes increased from 1.91 &times, 10&minus, 2 to 1.65 &times, 1 L h&minus, 1 m&minus, 2 bar&minus, 1 as the annealing temperature increased from 240 &deg, C to 270 &deg, C. The structure and properties of the PEEK hollow fiber membrane can be effectively controlled by regulating heat treatment conditions.

A series of polyarylates containing phosphorus (pho-PARs) were synthesized from bisphenol A with different molar ratios of bis-(4-carboxyphenyl) phenyl phosphine oxide (BCPPO) to terephthalic acid (TPA). When the contents of BCPPO are in the range of 0.4–1.0, the pho-PARs are readily soluble in a wide range of organic solvents and have the glass transition temperatures of 243.0–260.4°C. The initial degradation temperatures of these pho-PARs are all above 450°C and their char yields at 800°C under nitrogen atmosphere are in the range of 28.7–33.0%, suggesting they have excellent thermal stability. The results of TG-FTIR and FT-IR show the introduction of BCPPO change the decomposition model of the pho-PARs. The limiting oxygen indexes are at a range of 30.7–34.5%, which suggests that the pho-PARs are a kind of excellent inherent flame retardant materials. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3521–3529, 2013

In order to reduce the melt temperature (Tm) of the thermotropic crystalline polyarylate and improve its compatibility with poly(ether ether ketone) (PEEK), a series of poly(ether ketone)arylates (PEKARs) containing aryl ether ketone units (AEK) are synthesized through melt transesterification reaction from p-acetoxybenzoic acid, 1,3-bis(4′-carboxylphenoxy)benzene and 4,4′-bis(p-acetoxyphenoxy)benzophenone. The inherent viscosities of these polymers are in the range 0.35–0.81 dL/g. The morphologies and properties of PEKARs are characterized by polarized optical microscopy, wide-angle X-ray diffraction, differential scanning calorimetry, thermal gravimetric analysis, etc. The results show that all PEKARs are semi-crystalline polymers, and the introduction of AEK units can reduce the symmetry of the main chains, leading to decreasing the crystallizability and changing the crystalline form. The PEKARs with AEK less than 30% can exhibit thermotropic liquid crystalline state. The initial and the maximum decomposition temperatures increase with the increase in AEK content. These PEKARs are expected to act as processing agents for PEEK to reduce its processing viscosity. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

To improve the processability and properties of the poly(phenylene sulfide) (PPS) fibers at room temperature and high temperatures, a series of composite fibers based on PPS and multiwalled carbon nanotubes were prepared by melt spinning. We researched the processability with a high-pressure capillary rheometer, and the properties of the composite fibers were investigated in detail by scanning electron microscopy, differential scanning calorimetry, fiber sonic velocity measurement, and single-fiber strength testing. The results show that the carbon nanotubes (CNTs) had good interfacial adhesion with PPS and dispersed homogeneously in the PPS matrix. When the shear rate was higher than 500 s−1, the oriented CNTs induced the orientation of PPS molecular chains; this resulted in a decline in the apparent viscosity and an increase in the orientation degree of the molecular chains. Meanwhile, the CNTs acted as nucleating agents to effectively improve the crystallization of PPS. The strength of the fibers at room temperature were improved by 28.8% after the addition of 0.2% CNTs, and the initial modulus was also significantly enhanced. The strength retention at 160 °C was promoted from 60.58 to 88.32% with the addition of 1.0% CNTs. The shrinking percentage decreased to almost zero from higher than 15%; this suggested that the CNTs could efficiently improve the dimensional stability at high temperatures. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 134, 44609.

Here, a high breaking strength and high initial modulus fibers comprised of polyvinyl alcohol (PVA) and graphene oxide (GO) were fabricated via simple method of solution blending and wet-spinning. The structure and properties of these fibers were studied in details using two-dimensional X-ray diffractions, differential scanning calorimetry, one-dimensional X-ray diffractions, scanning electron microscopy, transmission electron microscopy, dynamic mechanical analysis and tensile test. Compared with pure PVA fiber, a 43 % improvement of breaking strength and an 81 % improvement of initial modulus were achieved by addition of 0.1 wt% of GO, and the results indicated that crystallization and orientation of GO/PVA composite fibers were both increased. GO could not only promote PVA chains ordered arrangement for increasing crystallization, but also act as a template for polymer amorphous orientation via the interactions between PVA and GO in the process of hot drawing and heat setting, which were responsible for the significant improvement in the mechanical properties of GO/PVA composite fibers.