Improvement and Evaluation of a Device That Determines the Interfacial Shear Strength of Carbon Fiber/Polyphenylene Sulfide Composites.

This study improved homemade apparatus for characterizing the interfacial shear strength (IFSS) of carbon-fiber-reinforced polyphenylene sulfide (PPS/CF) composites. The upgraded generation II experimental device includes a newly developed experimental clamp for samples, as well as testing systems. Compared with the initial generation I apparatus and the commercial Toei instrument, the generation II device is easier and more efficient to operate. The average interfacial adhesion values obtained using these devices were consistently approximately 40 MPa, with relatively low data scatter, showing excellent repeatability and applicability during microbond tests. Notably, the generation II experimental device was equipped with an additional high-frequency data-capturing tool to identify the debonding peak force more precisely, which demonstrated a higher interfacial shear strength of 42.81 MPa during testing. Therefore, the new instrument was able to reflect the change in the interfacial stress state during the interface debonding process more accurately and reliably.

Heat-Resistant and Color-Changing Luminescent Polysulfone for Information Encryption and Fire Alarming.

An intrinsic difficulty with thermally responsive photoluminescent materials is that high temperatures usually destroy luminance due to the notorious thermal quenching effect. Limited by the vulnerable chemical structure and soft skeleton, most of the existing photoluminescent responsive materials fail to indicate or work at a surging temperature over 100 °C, thus limiting application in display and alarming in harsh conditions. Herein, enlightened by chameleon's adaptive nature to external stimulus, we introduce a topologically optimized electron donor-acceptor (DA) structure and supramolecular interactions of lanthanide ions into the polymer backbone. The emission color determined by the DA structure is stable at high temperatures, and metal-ligand interaction phosphorescence is temperature-adjustable. Owing to the excellent reproducibility and heat resistance of composite films, the sensors can be bent into different three-dimensional structures and adhered to metal surfaces as flexible thermometers with superior display resolution. The polymer composite film could be directly applied as a photoluminescent quick response (QR) code, with patterns simultaneously variable to a temperature from 30 to 150 °C free of manual operation. More importantly, the polymeric composite could be in-situ-oxidized to a "sulfone" structure with an enhanced glass transition temperature of 297-304 °C. The heat- and flame-resistant characteristics of the oxidized films give rise to the application of fire alarming devices since it can locate the fire source and respond exactly depending on the distance from the fire. The unique display, encryption, and alarming functions of the polymeric composite studied in this work bring forward a new concept of developing a great information security and disaster monitoring system with the application of temperature-responsive materials.

New Strategy for Improvement of Interfacial Interactions between Poly(arylene sulfide sulfone) and Carbon Fiber by Grafting Polymeric Chains via Thiol-Ene Click Chemistry.

A simple and efficient strategy for enhancing the interfacial interaction in carbon fiber-reinforced poly(arylene sulfide sulfone) (CF/PASS) composites by grafting polymeric chains via thiol-ene click chemistry is reported here. Simultaneously, three thiol compounds and carbon nanotubes were grafted on CFs to explore the reaction between the CF and thiol groups. X-ray photoelectron spectroscopy, Raman spectroscopy, and normalized temperature-dependent IR spectroscopy results confirm the successful grafting of three thiol compounds, carbon nanotubes, and polymer chains. Similarly, obvious changes on the CF surface can be seen before and after modification via scanning electron microscopy, such as grafted nanotubes and polymeric resin, and the increase in the modulus gradient and interfacial thickness of CF/PASS can be clearly seen via atomic force microscopy. All the results of micro and macro tests on mechanical properties indicate that connecting low molecular weight thiol-terminated PASS (HS-LPASS) onto CFs enhances the interfacial property and mechanical performance of CF/PASS to a greater extent. The interfacial shear strength, interlaminar shear strength, and tensile strength of CF@HS-LPASS-reinforced PASS (CF@HS-LPASS/PASS) increase significantly by 38.5, 43.6, and 24.4%, respectively. All the results demonstrate that thiol-ene click reactions can be used for CF modification; furthermore, in the presence of external stress, the grafted polymeric interphase can act as a "bridge layer" to improve the stress transfer efficiency.

Improve the Interfacial Properties between Poly(arylene sulfide sulfone) and Carbon Fiber by Double Polymeric Grafted Layers Designed on a Carbon Fiber Surface.

Double polymeric grafted layer is constructed by two steps of chemical reaction, in which two polymers had been used, respectively polydopamine (PDA) film and modified PASS (NH2-PASS) resin containing amine group, as the interphase in carbon fiber reinforced poly(arylene sulfide sulfone) (PASS) composite (CF/PASS) to work on enhancing the interfacial property. All the test results of chemical components and chemical structures on the carbon fiber surface show that the double polymeric grafted layer was constructed successfully with PDA and NH2-PASS chains. And obvious characteristics of thin PDA film and a polymer layer can be clearly seen in the morphology of modified carbon fiber. In addition to this, the obvious interphase and change in the thickness of interphase have been observed in the modulus distribution images of CF/PASS. The final superb performance is achieved by PASS composites with a double polymeric grafted layer, 27.2% and 198.6% superior to the original PASS composite for IFSS and ILSS, respectively. Moreover, the result also indicates that constructing a double polymeric grafted layer on a carbon fiber surface is a promising technique to modify carbon fiber for processing high-performance advanced thermoplastic composites and is more environmental friendly as well as convenient.

Multilevel structured PASS nanofiber filter with outstanding thermal stability and excellent mechanical property for high-efficiency particulate matter removal.

Particulate matter (PM) pollution from industrialization poses a great threat to people's health. Although fiber-based filters are used effectively to capture PM, the traditional filters with large diameter suffer from low filtration efficiency, high pressure drop and low temperature resistance. In this study, multilayer poly arylene sulfide sulfone (M-PASS) composite filter was designed and fabricated via electrospinning technology. The M-PASS composite filter is sandwich-structure. Due to the unique structure and composition, the M-PASS filter exhibited outstanding removal efficiency of 99.97 ± 0.0050%, extremely low air resistance of 44.3 ± 0.7 Pa, excellent quality factor (QF) of 0.19 ± 0.0019 Pa-1, and desirable mechanical strength of 7.0 ± 0.2 MPa. Furthermore, the as-prepared M-PASS filter can remain outstanding filtration performance at 200.0 â„ƒ due to the high thermal stability of PASS and the removal efficiency was still above 95.2 ± 0.4% after long-term filtration test. These results demonstrate that the structure of filter is the important one for air filtration and the M-PASS nanofiber filters have great potential in PM removal, especially under high temperature conditions.

High-performance filter membrane composed of oxidized Poly (arylene sulfide sulfone) nanofibers for the high-efficiency air filtration.

In this study, a novel, oxidized poly (arylene sulfide sulfone) (O-PASS) nanofibrous membrane filter was successfully fabricated for the effective removal of particulate matter. PASS was electrospun into a nanofibrous membrane with an average nanofiber diameter of 0.31 µm and basis weight of 3 g/m2. These specifications were chosen as they showed high particulate matter removal efficiency (99.98%), low pressure drop (68 Pa), and high quality factor QF (0.125 Pa-1). In addition, the filtration mechanism of the PASS nanofibrous membrane was intuitively revealed by simulating the intercepted particular distributions and motion paths of particles. After a simple oxidation treatment, the O-PASS nanofibrous membrane was successfully built up. The microstructure and morphology showed little change compared with the PASS nanofiber, but the oxidation treatment significantly improved the mechanical properties of the membrane from 1.51 MPa to 4.92 MPa. More importantly, the O-PASS nanofibrous membrane still exhibited high removal efficiency after high temperature, acid, alkali, or organic solvent treatments. Overall, O-PASS nanofibrous membranes are promising high-performance filter materials with high temperature and corrosion resistance.

Synthesis, Characterization and Non-Isothermal Crystallization Kinetics of a New Family of Poly (Ether-Block-Amide)s Based on Nylon 10T/10I.

A series of novel thermoplastic elastomers based on (poly(decamethylene terephthalamide/decamethylene isophthalamide), PA10T/10I) and poly(ethylene glycol) (PEG) were synthesized via a facile one-pot, efficient and pollution-free method. The thermal analysis demonstrates that the melting points of the resultant elastomers were in the range of 217.1-233.9 °C, and their initial decomposition temperatures were in the range of 385.3-387.5 °C. That is higher than most commercial polyamide-based thermoplastic elastomers. The tensile strength of the resultant elastomers ranges from 21.9 to 41.1 MPa. According to the high-temperature bending test results, the resultant samples still maintain considerably better mechanical properties than commercial products such as Pebax® 5533 (Arkema, Paris, France), and these novel thermoplastic elastomers could potentially be applied in high-temperature scenes. The non-isothermal crystallization kinetics of the resultant elastomers and PA10T/10I was investigated by means of Jeziorny and Mo's methods. Both of them could successfully describe the crystallization behavior of the resultant elastomers. Additionally, the activation energy of non-isothermal crystallization was calculated by the Kissinger method and the Friedman equation. The results indicate that the crystallization rates follow the order of TPAE-2000 > TPAE-1500 > PA10T/10I > TPAE-1000. From the crystallization analysis, the crystallization kinetics and activation energies are deeply affected by the molecular weight of hard segment.

Fabrication of novel dual thermo- and pH-sensitive poly (N-isopropylacrylamide-N-methylolacrylamide-acrylic acid) electrospun ultrafine fibres for controlled drug release.

Dual temperature- and pH-sensitive materials used as drug carriers have attracted a particularly high level of interest. However, it is limited by low sensitivity to changes in conditions because of large size and low specific surface area. In this work, novel dual temperature- and pH-sensitive poly(N-isopropylacrylamide-N-methylolacrylamide acrylic acid) (PNIPAm-NMA-AAc) ultrafine fibres were successfully prepared by radical copolymerisation, electrospinning and thermal chemical treatment. The PNIPAm-NMA-AAc ultrafine fibres were characterized by Fourier transform infrared (FTIR), proton nuclear magnetic resonance (1H NMR), spectroscopy UV-visible spectroscopy, scanning electron microscopy (SEM) and cell counting kit-8 (CCK-8) assay. The uniformity and small size of PNIPAm-NMA-AAc ultrafine fibres with LCST range from 31 °C to 43 °C were used to drug carrier because of good thermal stability, no cytotoxic. Curcumin as a model drug was well distributed in PNIPAm-NMA-AAc ultrafine fibres. In addition, analysis of curcumin release at different pH values and temperatures confirmed that the PNIPAm-NMA-AAc ultrafine fibres are responsive to both temperature and pH. The maximum amount of curcumin released was 98.47% ±â€¯1.87%. In addition, the release mechanism of curcumin-based PNIPAm-NMA-AAc ultrafine fibres was shown to conform to Fickian diffusion (r2 ≥ 0.95). These results indicated that dual-responsive PNIPAm-NMA-AAc ultrafine fibres are promising as drug carriers.

Segregated poly(arylene sulfide sulfone)/graphene nanoplatelet composites for electromagnetic interference shielding prepared by the partial dissolution method.

Segregated conductive polymer composites have been proved to be outstanding electromagnetic interference shielding (EMI) materials at low filler loadings. However, due to the poor interfacial adhesion between the pure conductive filler layers and segregated polymer granules, the mechanical properties of the segregated composites are usually poor, which limit their application. Herein, a simple and effective approach, the partial dissolution method, has been proposed to fabricate segregated poly(arylene sulfide sulfone) (PASS)/graphene nanoplatelet (GNP) composites with superior EMI shielding effectiveness (SE) and high tensile strength. Morphology examinations revealed that the GNPs were restricted in the dissolved outer layer by the undissolved cores, and there was a strong interaction between the PASS/GNP layer and the pure PASS core. The resultant PASS/GNP composites showed excellent electrical conductivity (60.3 S m-1) and high EMI SE (41 dB) with only 5 wt% GNPs. More notably, the tensile strength of the PASS/GNPs prepared by partial dissolution reached 36.4 MPa, presenting 136% improvement compared to that of the conventional segregated composites prepared by mechanical mixing. The composites also exhibited high resistance to elevated temperatures and chemicals owing to the use of the special engineering polymer PASS as a matrix.

Novel PNIPAm-based electrospun nanofibres used directly as a drug carrier for "on-off" switchable drug release.

Stimuli-responsive smart polymers have been studied extensively. In this work, thermoresponsive poly (N-isopropylacrylamide-N-methylolacrylamide-acrylamide) (PNIPAm-NMA-Am) was successfully synthesised via radical polymerisation, as confirmed by proton nuclear magnetic resonance and fourier transform infrared spectroscopy. PNIPAm-NMA-Am was electrospun into nanofibres, allowing its use as a drug carrier after simple thermal treatment. Thermogravimetric analysis, scanning electron microscopy, and atomic force microscopy results also revealed that the as-prepared PNIPAm-NMA-Am nanofibres have a uniform small diameter, good thermal stability and excellent integrity in aqueous environments. Additionally, the properties of this PNIPAm-NMA-Am nanofibres were tunable with temperature changes below and above the lower critical solution temperature of 48 °C. The drug release properties of PNIPAm-NMA-Am10 nanofibres as a drug carrier were studied via ultraviolet-visible spectroscopy and the results showed that 80% of the drug was released from the nanofibres after six heating and cooling (60-10 °C) cycles within 60 min. Only a small amount of the drug was released during the cooling process, which directly demonstrates "on-off" functionality of PNIPAm-NMA-Am nanofibres for controlled drug release. Finally, cell culture studies indicated that the PNIPAm-NMA-Am nanofibres have not cytotoxicity. Thus, the novel PNIPAm-NMA-Am nanofibres show great potential in the biomedical field as drug carriers.

Release characteristics and processing-structure-performance relationship of electro-spinning curcumin-loaded polyethersulfone based porous ultrafine fibers.

Polymeric porous ultrafine fibers with different structures as drug carrier could be facilely prepared. However, the drug release characteristics and relevant mechanism of different structural porous ultrafine fibers were not well studied. In the present work, different structural Poly-Ether-Sulfone (PES) based porous ultrafine fibers, namely PES, PES/Poly-Ethylene-Glycol (PEG) and PES/Water were prepared by electro-spinning. Curcumin was chosen as drug model loaded in these fibers. Investigation of curcumin release characteristics was carried out by the total immersion in buffer solution. The surface and inner structure of PES based ultrafine fibers were studied by scanning electron microscopy (SEM) in detail. It is found that there is significant difference in the accumulate release amount and release rate with similar structure. About 92.5% of curcumin released within 600 min for PES/PEG ultrafine fibers and only 58.9% of curcumin flowed out from PES with 1000 min. In order to discuss the fact of this phenomenon, the development structure of PES based porous ultrafine fibers was studied with curcumin release. The results indicated that the curcumin release was directly involved with the structure. For PES/PEG, curcumin around the surface layer released in advance. And then, some penetrable structure emerged with PEG dissolving in the buffer solution, which result in larger specific surface area and more embedded curcumin from the interior structure of the ultrafine fibers diffusing out. For the others, curcumin release only through its own pores of ultrafine fibers. Finally, the processing-structure-performance relationship of PES based porous ultrafine fibers were confirmed by the diversity of porosity and contact angle. The research results demonstrate that PES based porous ultrafine fibers have the potential to be used as drug carrier in the drug delivery according to the practical clinical requirements.

Preparation of the poly(arylene sulfide sulfone)/multi-walled carbon nanotubes composites via in situ polymerization.

The nanocomposites of Multiwall carbon nanotubes (MWNTs) and poly(arylene sulfide sulfone) (PASS) were prepared via in situ polymerization. The compounds were found to distribute uniformly and had excellent thermal properties with glass transition temperatures (T(g)) of 222-224 degrees C and initial degradation temperature (T(d)) of 437.7-445 degrees C. They had better solubility and could dissolve in strong aprotic solvents such as N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), dimethyl sulfoxide (DMSO) and so on. After acidification and fluobenzene-functionalization treatment, the MWNTs and polymer matrix via in situ polymerziation showed better compatibility than the composite mixing directly. Additionally, the composites prepared via in situ polymerization had good electrical conductivity of 10(14)-10(7.6) omega x m and mechanical properties with Young's modulus of 0.63-1.08 GPa.

Bis[4-(4-amino-phenyl-sulfanyl)phenyl] ketone.

The mol-ecule of the title compound, C(25)H(20)N(2)OS(2), has imposed twofold rotation symmetry. The dihedral angle formed by the two crystallographically independent phenyl rings is 79.23 (7)°. In the crystal packing, the mol-ecules are linked by inter-molecular N-H⋯O hydrogen bonds, forming chains running parallel to [102].