Preparation of hollow poly(imino ether ketone) microspheres by microliquid technique

1, 4‐bis (4‐amiophenoxy) benzene and 1, 4‐Bis (4‐bromobenzoyl) benzene as monomers, poly(imino ether ketone) (PIEK) was synthesized via palladium‐catalyzed aryl amination reaction. Based on the good chemical and physical properties, big diameter (0.6–2 mm) hollow microspheres of PIEK, used for Inertial Confinement Fusion research, were prepared by using the microliquid technique and double‐layer latex technique. A new double T‐channel droplet generator was designed and developed for fabrication of controlled‐size PIEK hollow microspheres continuously. Study on manipulative condition of diameter and thickness of microspheres was done, and density matching impacting on the quality of shells was discussed. The structures of the PIEK hollow microspheres were characterized, and they possessed equal wall thickness and good spherical symmetry. The properties of the microspheres were detected, and the results showed that they showed good stability under cold environment and high temperature. Additionally, the PIEK hollow microspheres exhibited good mechanical and anti‐irradiation properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

The effect of soft‐segment structure on the properties of novel thermoplastic polyurethane elastomers based on an unconventional chain extender

Thermoplastic polyurethane elastomers (TPUs) are now widely used because of their excellent properties that include high tensile and tear strength, and good abrasion, impact and chemical resistance. TPUs are multiblock copolymers with alternating sequences of hard segments composed of diisocyanates and simple diols (chain extenders) and soft segments formed by polymer diols. Commonly used hard segments for TPUs are derived from 4,4′‐diphenylmethane diisocyanate (MDI) and aliphatic diols. The aim of our research was to examine the possibility of obtaining TPUs with good tensile properties and thermal stability by using an unconventional aliphatic‐aromatic chain extender, containing sulfide linkages. Three series of novel TPUs were synthesized by melt polymerization from poly(oxytetramethylene) diol, poly(ε‐caprolactone) diol or poly(hexane‐1,6‐diyl carbonate) diol of number‐average molecular weight of 2000 g mol^?1 as soft segments, MDI and 3,3′‐[methylenebis(1,4‐phenylenemethylenethio)]dipropan‐1‐ol as a chain extender. The structure and basic properties of the polymers were examined using Fourier transfer infrared spectroscopy, X‐ray diffraction, atomic force microscopy, differential scanning calorimetry, thermogravimetric analysis, Shore hardness and tensile tests. It is possible to synthesize TPUs from the aliphatic‐aromatic chain extender with good tensile properties (strength up to 42.6 MPa and elongation at break up to 750%) and thermal stability. Because the structure of the newly obtained TPUs incorporates sulfur atoms, the TPUs can exhibit improved antibacterial activity and adhesive properties. Copyright © 2011 Society of Chemical Industry     

A novel mica‐based composite with hybrid aramid fibers for electrical insulating applications: largely improved mechanical properties and moisture resistance

The fabrication of mica‐based composites with good mechanical properties is very important especially for electrical insulation applications. In this study, a new aramid fibrid along with chopped fibers was introduced into a mica system, and the composites were prepared using a papermaking machine. It was found that the mechanical properties of both fibrid–mica composite (F‐M paper) and fiber/fibrid–mica composite (A‐M paper) were largely improved in comparison with the reference sample (M paper) with an increase in the content of fibrid or hybrid floc/fibrid. This enhancement can be attributed to two mechanisms: (1) enhanced interfacial adhesion derived from the addition of fibrids with good flexibility and wrapping properties and (2) significant reinforcing due to the frameworks originating from the addition of chopped flocs with high modulus and rigid‐rod morphology. Interestingly, a synergetic effect of enhanced interfacial adhesion and reinforcing could also be observed when both flocs and fibrids were introduced, which further improved the mechanical properties. Furthermore, the addition of aramid fibrid greatly enhanced the moisture resistance, which expands the potential for mica‐based composites. Thus, we successfully fabricated a mica‐based composite for electrical insulation with good mechanical properties, high end‐use temperature and excellent moisture resistance by adding hybrid aramid fibers. © 2017 Society of Chemical Industry     

Electrosynthesis,characterization, and application of poly(3,4‐ethylenedioxythiophene) derivative with a chloromethyl functionality

Poly(2‐chloromethyl‐2,3‐dihydrothieno[3,4‐b][1,4]dioxine), a chloromethyl functionalized poly(3,4‐ethylenedioxythiophene) derivative (PEDOT‐MeCl), was synthesized electrochemically via the potentiostatic polymerization of its monomer in dichloromethane solution containing suitable tetrabutylammonium tetrafluoroborate, then it was used for the characterization of film properties and the fabrication of electrochemical sensor. The properties of the resulting PEDOT‐MeCl film were characterized by different methods such as cyclic voltammetry, electrochemical impedance spectroscopy, Fourier transform infrared and ultraviolet–visible techniques, scanning electron microscope, and thermogravimetric analysis. The PEDOT‐MeCl film displayed a good reversible redox activity, remarkable capacitance properties, good thermal stability, rough, and porous structure, especially fluorescent spectra indicated that PEDOT‐MeCl was a blue‐emitter with maximum emission centered at 396 and 398 nm. Finally, the PEDOT‐MeCl film was employed for the fabrication of the sensing electrode, and dopamine was chosen as a model analyte for the application of the electrochemical sensor. Results indicated that the PEDOT‐MeCl film as sensing interface was feasible, and studies of these film properties were very beneficial for studying properties and applications of other poly(3,4‐ethylenedioxythiophene) derivative films. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2660–2670, 2013     

Dyeing properties of novel electrolyte‐free reactive dyes on cotton fibre

A series of electrolyte‐free reactive dyes containing two quaternary ammonium salt groups as soluble moieties and one epoxy structure as the reactive group have been synthesised. The structures of the synthesised dyes were confirmed by Fourier Transform–infrared, proton nuclear magnetic resonance and elemental analysis, and their dyeing properties on cotton were studied using an electrolyte‐free dyeing process. The results indicate that electrolyte‐free reactive dyes with these structures give a high exhaustion rate, a high fixation rate and good build‐up properties on cotton. Fastness properties were, in general, also very good. The optimal dyeing process of these electrolyte‐free dyes for cotton fibre was 60 °C with 20 g/l sodium carbonate.     

Blends of sulfonated polysulfone/polysulfone/4,4′‐diaminodiphenyl methane‐based benzoxazine: multiphase structures and properties

To overcome the brittleness of polybenzoxazine and decrease its high curing temperature, sulfonated polysulfone/polysulfone/benzoxazine ternary blends were prepared, and their curing behaviors, phase structures and properties were probed. Sulfonated polysulfone (SPSU) was synthesized firstly, and then SPSU was applied to modify 4,4′‐diaminodiphenyl methane based benzoxazine (BZ‐m) along with polysulfone. The results obtained from differential scanning calorimetry showed that the addition of SPSU efficiently decreased the curing temperature of BZ‐m, and furthermore affected the phase structures of SPSU/PSU/PBZ‐m blends. The phase structures of the corresponding blends were confirmed by scanning electron microscopy and dynamic mechanical analysis to probe the relationship between the microstructures and mechanical properties. According to the results, the blends presented complicated phase structures and exhibited good comprehensive mechanical properties. Moreover, all the blends displayed good thermal stability and the blends with SPSU‐PBZ‐m core ? shell particles and a phase inversion structure exhibited the highest comprehensive mechanical properties. We believe these blends can meet the requirement of applications relating to high strength and good toughness matrix for fiber reinforced composites. © 2014 Society of Chemical Industry     

Hydroxyalkoxy derivatives of oxamic acid: polyol substrates for polyurethane foams

BACKGROUND: The work reported aimed at obtaining hydroxyalkoxy derivatives containing oxalamidoester groups starting from oxamic acid (OA) substrate. These derivatives were then used for the synthesis of polyurethane foams. RESULTS: The hydroxyalkoxy derivatives were obtained by reaction of OA with 6 to 15 molar excess of ethylene carbonate (1,3‐dioxolane‐2‐one) or propylene carbonate (4‐methyl‐1,3‐dioxolane‐2‐one). The products obtained have good thermal stability and possess suitable physical properties for use as substrates for foamed polyurethanes. CONCLUSION: The rigid polyurethane foams obtained from the hydroxyalkoxy derivatives of OA possess enhanced thermal stability and good mechanical properties in comparison with traditional polyurethane foams. Copyright © 2009 Society of Chemical Industry     

Organo bifunctional silane effects on the vibration,thermal, and mechanical properties of a vinyl‐group‐containing silicone rubber/natural rubber/silica compound

A bifunctional silane (TESPD) was added to a vinyl‐group‐containing silicone rubber (SR)/natural rubber (NR)/silica compound, and the resulting mechanical, morphological, and thermal properties were compared with those of an NR/silica compound. The addition of TESPD to the silica‐filled SR/NR compound formed an SR‐silane‐silica‐silane‐NR structure that behaved as a ter‐polymer. The addition of SR into the NR improved the mechanical properties (torque maximum, modulus, elongation at break, and hardness) and thermal properties as well as the tan δ values. The SR‐silane‐silica‐silane‐NR structure exhibited advanced properties that are suitable for an automotive engine mount application, which requires good thermal and vibration absorption properties. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers     

Simultaneously Improving the Thermal,Flame‐Retardant and Mechanical Properties of Epoxy Resins Modified by a Novel Multi‐Element Synergistic Flame Retardant

To obtain epoxy resins with satisfactory thermal, flame retardant, and mechanical properties, a novel multi‐element synergistic flame retardant (PPVSZ) is synthesized through the reaction between P? H of 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) and C?C of polysilazane (PVSZ) and utilized as a multi‐element synergistic flame retardant for epoxy resins. The flame retardant mechanism is explored by XPS and SEM, confirming that the excellent flame‐retardance efficiency owes itself to an optimal flame retardant way which jointly exerts the flame‐retardant effects in the gaseous and condensed phase. The thermal properties deduced from DSC, TGA, and DMA, indicate the glass transition temperature, maximum weight loss rate, and char yields at 700 °C for EP‐2 increase by about 5.0 °C, 8.4 °C and 8.8%, respectively. Furthermore, mechanical properties such as impact strength, tensile strength, and flexural strength are also increased by 45.38%, 14.16%, and 17.43%, respectively, which show that the incorporation of PPVSZ does not deteriorate the mechanical properties of modified resin. All the results demonstrate that epoxy resins modified by PPVSZ not only have good effect on the flame retardance, but also have good improvement on thermal and mechanical properties, indicating the potential for applications in many fields requiring fire safety.     

Influence of surface modification of carbon nanotube on microstructures and properties of polyamide 66/multiwalled carbon nanotube composites

The melt‐mixing polyamide 66 (PA66) composite samples that incorporated pure, acid‐ and amine‐functionalized multiwalled carbon nanotubes (MWCNTs) were prepared in order to enhance mechanical and frictional properties of PA66 composites. The homogeneous dispersion of amine‐functionalized MWCNTs (D‐MWCNTs) in PA66 matrix was observed from the significantly uniform morphology of tensile fractured surface of the composites. Differential scanning calorimetry measurement indicates that D‐MWCNTs acted as effective nucleation agent for PA66 matrix and the crystallinity of PA66 was increased. The fracture stress and tensile modulus of the composites were significantly improved with the incorporation of D‐MWCNTs, owing to the good dispersion of D‐MWCNTs. Compared with PA66, the PA66 composites with 1.0 wt% D‐MWCNTs were improved considerably in both wear and friction properties owing to the change of the tribological mechanisms. The good dispersion of D‐MWCNTs in PA66 and good interface compatibility between D‐MWCNTs and PA66 favored the formation of a thin layer on the contact surfaces during wear and friction test, which played an important role in reducing wear and friction of the composite and in suppressing the transverse cracks. These results prove the importance of D‐MWCNTs in a positive change of the mechanical and frictional properties of PA66 composites and suggest the applicability prospect of PA66/D‐MWCNTs composites in engineering components.POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers     

One‐pot curing system of epoxy resin imines initiated with water

The curing and adhesive properties of one‐component epoxy resins containing Epikote 828 and diimines, derived from N,N′‐di(1‐ethylpropylidene)‐m‐xylylenediamine, N,N′‐di(1‐ethylpropylidene)‐1,3‐diaminomethylcyclohexane (2), and N,N′‐di(1,3‐dimethylbutylidene)‐m‐xylylenediamine, which were used as water‐initiated hardeners, were examined. Diethyl ketone‐based imines with a lower electron density on the C?N carbon were efficiently hydrolyzed and showed curing activity. 2, a novel diethyl ketone‐based diimine, served as an efficient latent hardener of the epoxy resin. A paste of the epoxy resin with 2 showed good storage stability at room temperature and good adhesive properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 878–882, 2003     

Energetic Material Detonation Characterization: A Laboratory‐Scale Approach

A novel energetic‐material detonation and air‐blast characterization technique is proposed through the use of a laboratory‐scale‐based modified “aquarium test.” A streak camera is used to record the radial shock wave expansion rate at the energetic material air interface of spherical laboratory‐scale (i.e., gram‐range) charges detonated in air. A linear regression fit is applied to the measured streak record data. Using this in conjunction with the conservation laws, material Hugoniots, and two empirically established relationships, a procedure is developed to determine fundamental detonation properties (pressure, velocity, particle velocity, and density) and air shock wave properties (pressure, velocity, particle velocity, and density) at the energetic material air interface. The experimentally determined properties are in good agreement with published values. The theory’s applicability is extended using historical experimental test data due to the limited number of experiments able to be performed. Predicted detonation wave and air shock wave properties are in good agreement for a multitude of energetics across various atmospheric conditions.     

Morphological and mechanical properties of PP/ABS blends compatibilized with PP‐g‐acrylic acid

Polypropylene (PP) and acrylonitrile–butadiene–styrene (ABS) blends were prepared by a melt extrusion process. PP‐g‐acrylic acid was used as a compatibilizer. Blends with various compositions of PP, compatibilizer, and ABS were prepared and studied for morphological and mechanical properties. PP‐rich ternary blends showed good morphological and mechanical properties. The use of 5 wt % PP‐g‐acrylic acid as a compatibilizer resulted in a fine and homogeneous dispersion of the ABS phase in the PP phase. The experimental data of the tensile modulus showed good agreement in PP‐rich compositions with that generated from Kerner's model with perfect adhesion. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1731–1741, 2001     

Toughened epoxy resin matrix for a membrane shell by wet filament winding

A toughened epoxy resin matrix was obtained with a reactive toughening agent and methyl hexahydrophthalic anhydride as a curing agent. The mechanical properties of the modified epoxy resin and its glass‐fiber‐reinforced composites were investigated systematically. The modified epoxy resin matrix possessed many good properties, including a high flexural strength (138 MPa), high elongation at break (5.2%), low viscosity, long pot life at room temperature, and good water resistance. In addition, the glass‐fiber‐reinforced composites showed a high strength conversion ratio of the glass fiber (86.7%) and good fatigue resistance. The results demonstrated that the modified epoxy resin matrix is very suitable for applications in reverse osmosis membrane shell products fabricated with wet filament winding for water treatment. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Cellulose acetate/multiwalled carbon nanotube nanocomposites with improved mechanical,thermal, and electrical properties

Cellulose acetate (CA)‐based nanocomposites with various contents of neat multiwalled carbon nanotube (MWCNT) or acid‐treated one (MWCNT‐COOH) are prepared via melt‐compounding method and investigated their morphology, thermal stability, mechanical, and electrical properties. SEM microphotographs reveal that MWCNT‐COOHs are dispersed uniformly in the CA matrix, compared with neat MWCNTs. FTIR spectra support that there exists a specific interaction between carboxyl groups of MWCNT‐COOHs and ester groups of CA, indicating good interfacial adhesion between MWCNT‐COOHs and CA matrix. Accordingly, thermal stability and dynamic mechanical properties of CA/MWCNT‐COOH nanocomposites were higher than those of CA/MWCNT composites. On the contrary, electrical volume resistivities of CA/MWCNT‐COOH nanocomposites are found to be somewhat higher than those of CA/MWCNT composites, which is because of the deterioration of graphene structures for MWCNT‐COOHs and the good dispersion of MWCNT‐COOHs in the CA matrix. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Curing behavior and thermal mechanical properties of cyanate ester blends

Cyanate esters are a class of important thermally resistant polymers. To tailor their processability and thermomechanical properties, a series of cyanate ester blends based on a trifunctional novolac cyanate ester (HF‐5), a difunctional bisphenol E cyanate ester (HF‐9), and a reactive catalyst [2,2′‐diallyl bisphenol A (DBA)] were formulated. The effect of the blend composition on the rheology and curing behavior of these cyanate ester blends and the corresponding thermal and mechanical properties of the cured cyanate ester blends was studied. The results showed that HF‐5 contributed to good mechanical property retention at high temperatures because of its trifunctionality, whereas HF‐9 imparted processability by reducing the viscosity and extending the pot life of the formulated cyanate ester blends at the processing temperature. On the basis of the results, an optimal cyanate ester blend suitable for resin transfer molding was determined: the HF‐5/HF‐9/DBA weight ratio of 80 : 15 : 5 exhibited good processability and thermomechanical properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4284–4290, 2006     

Chemical modification of 3,3′,4,4′‐biphenyltetracarboxylic dianhydride polyimides by a catechol‐derived bis(ether amine)

Having previously demonstrated that the polyimide derived from 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (BPDA) and 1,2‐bis(4‐aminophenoxy)benzene [termed triphenyl ether catechol diamine (TPEC)] exhibited superior tensile properties in addition to good thermal properties, we now provide a preliminary assessment of the properties of the copolyimides prepared from BPDA, TPEC, and another aromatic diamine. The homopolyimides derived from BPDA and many aromatic diamines generally possessed good mechanical properties and thermal properties; however, they were insoluble in available organic solvents. In several cases, organosoluble BPDA copolyimides could be prepared from BPDA and equimolar mixtures of TPEC and another aromatic diamine. All the copolyimides could be formed into tough films with high moduli and strengths and, in most cases, high extensions to break. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 351–358, 2002; DOI 10.1002/app.10342     

Effective hole‐injection characteristics of organic light‐emitting diodes due to fluorinated self‐assembled monolayer embedded as a buffer layer

The electrical and optical properties of organic light‐emitting diodes (OLEDs) are demonstrated by varying the length of the alkyl chain of a fluorinated self‐assembled monolayer (F‐nSAM). OLEDs containing F‐nSAMs that have a long alkyl chain length were found to exhibit excellent properties in terms of current density, luminance, turn‐on voltage, etc. The obtained current density at 6 V, which was the highest measurement voltage, was up to about 36 times higher for an OLED including an F‐12SAM thin film with the longest chain length than for an OLED including only an indium tin oxide (ITO) substrate. With regard to luminance characteristics depending on voltage, the luminance was about 13 times higher for the OLED including the F‐12SAM thin film than for the OLED including only the ITO substrate. Also, the turn‐on voltage of the OLED including the F‐12SAM thin film was decreased by approximately 1 V compared to that of the OLED including only the ITO substrate. Although F‐nSAMs with alkyl chains have insulating film properties, F‐nSAMs with long alkyl chains exhibited good electrical and optical properties because of an improvement in the hole‐injection barrier due to a large positive shift of the vacuum level and smooth carrier injection resulting from a high contact angle due to strong hydrophobic properties caused by the good alignment properties of F‐nSAMs resulting from strong van der Waals forces between the molecules due to the long alkyl chains. © 2019 Society of Chemical Industry     

Synthesis and characterization of soluble poly(ether imide)s containing fluorenyl cardo groups

Two series of poly(ether imide)s (PEIs) containing fluorenyl cardo groups in the main chains were synthesized, which are derived from the polycondensation of 9,9′‐bis(4‐aminophenoxyphenyl)fluorene (BAOFL) or 9,9′‐bis(3‐trifluoromethyl,4‐aminophenoxyphenyl)fluorene (6F‐BAOFL) with four kinds of dianhydrides (3,3′,4,4′‐biphenyltetracarboxylic dianhydride, 4,4′‐oxydiphthalicanhydride, 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride, and bisphenol‐A dianhydride), respectively. The PEI films and PEI powder were prepared by thermal and chemical imidization, respectively. The PEIs were characterized by FTIR, ¹H‐NMR, differential scanning calorimetry, thermogravimetric analysis, and UV–vis were performed on inherent viscosity, solubility, and tensile tests. The effects of fluorenyl cardo groups and ether linkages on the solubility, tensile properties, thermal stability, and optical properties were investigated in detail. It was found that the PEIs had good solubility in common organic solvents and good optical transparency in visible light region. In addition, the PEI films exhibited excellent tensile and thermal properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Poly(dl‐Lactic Acid)‐Based Linear Polyurethanes Capable of Forming Physical Crosslinking via UPy Quadruple Hydrogen Bonding Assembly

Linear shape memory polyurethanes based on poly(dl ‐lactic acid) (PDLLA) macrodiol (PDLLA‐SMPUs) have various advantages such as good processability, biodegradability, shape memory effect, and biocompatibility, yet the insufficient mechanical properties prevent their effective applications in bone repair. 2‐Ureido‐4[1H]‐pyrimidone (UPy) can form strong quadruple hydrogen bonding. Here, a new linear PDLLA‐SMPU containing pendant UPy units (UPy‐p‐PDLLA‐SMPU) is designed and synthesized. The pendant UPy units may dimerize to form physical crosslinking among UPy‐p‐PDLLA‐SMPU chains. As a result, UPy‐p‐PDLLA‐SMPU demonstrates both good processability and significantly higher mechanical properties than the corresponding linear PDLLA‐SMPU without pendant UPys. In addition, UPy‐p‐PDLLA‐SMPU shows excellent shape memory effect near body temperature, with a shape fixity ratio of up to 98.6% and a recovery ratio of up to 92.9%. This work provides a new strategy to design SMPUs integrating the merits of linear and crosslinked polyurethanes, and the obtained UPy‐p‐PDLLA‐SMPU is a promising material for bone tissue repair in view of the mechanical, thermal, and shape memory properties.