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Polyurethane (PU) is a versatile material that can be customized to meet specific commercial requirements in different industries because of its favorable mechanical properties. However, it is not resistant to high temperatures, and it requires structural modifications before it can be used in high‐temperature structural materials. In this study, isocyanates and anhydrides are copolymerized at high temperatures to obtain a solvent‐free oligomer, thus eliminating the risks associated with highly polar aprotic solvents. A casting technique is used to synthesize a solid poly(urethane‐imide) (PUI) elastomer. According to the results, casting PUI (CPUI) exhibits optimal physical properties at a hard segment content of 30.5%. Incorporating an ether, symmetric, or imide structure into CPUI may reduce its hysteresis and improve its thermal creep performance. Compared with PU, CPUI exhibits considerably higher creep aging resistance. In dynamic load application tests, CPUI wheels take a substantially longer time to reach failure compared with PU wheels. Overall, CPUI is an environmentally friendly material with high elasticity, low creep, and high heat aging resistance and is suitable for static and dynamic manufacturing applications. [ABSTRACT FROM AUTHOR]

A series of polyurethane (PU) copolymers was synthesized by 4,4‐Methylene diphenyl diisocyanate (MDI) with different polyols of polyether, polyether carbonate (PEC), and polycarbonate with the same molecular weight via a one‐step copolymerization process. The synthesized PU containing the ether carbonate groups exhibited a relatively higher glass transition temperature (Tg) above 45°C; in comparison, a value of 12.4°C for the polycarbonate sample and −22°C for the polyether sample was observed. The film made of PEC samples produced by solvent indicated an increment of Tg from 14.6 to 59.6°C after annealing for 6 h, which might be due to the rearrangement of chain structure, which led to an assembling of carbonate groups and resulted in a hindrance of chain mobility. For shape memory examination of the PU copolymers, all samples showed remarkable ability as recovery rate above 91% after 3 cycles test. PEC‐type PU polymers reveal potential high‐temperature micro shape memory material applications. [ABSTRACT FROM AUTHOR]

In this work, a novel crosslinked polyamide (cPA) system with hybrid polymer networks was developed. The hexamethylenediamine, acrylic acid (AA), and bis(6‐aminohexyl) dodecanediamide (BAHD) were utilized as the main building block in crosslinked polyamide (cPA) system by Michael addition reaction and polycondensation, wherein an amide diamine monomer, BAHD, was utilized as the building provider of hydrogen‐bonding networks. Simultaneously, the internal covalent bond networks were constructed by the Michael addition between AA and diamine, resulting in permanent covalent crosslinks. By adjusting the ratio of BAHD content, a series of copolyamides were successfully synthesized, and the thermal, mechanical, and viscoelastic behavior of cPAs were systematically discussed. Based on these results, the best mechanical properties in our cPAs were found in the composition of BH37, which exhibited microcrystalline behavior and outstanding tensile properties with melting temperature of 55°C, tensile strength above 45 MPa, and elongation at break above 1000%. It demonstrated that the adjusting of reversible hydrogen bonds and permanent covalent crosslinks in hybrid polymer networks could effectively endow the cPAs with excellent flexibility and strength. These studies provide useful information for designing novel cPA materials with controlled thermal and mechanical properties, which suggested the potential for use in advanced application fields. [ABSTRACT FROM AUTHOR]

Nonisocyanate polyurethane (NIPU) was synthesized using different concentrations of C36‐alkylenediamine (C36DDA), hexamethylene diamine, and a cyclic carbonate monomer synthesized from bisphenol A epoxy resin and carbon dioxide. The structures, molecular weights, thermal behaviors, and stabilities of the NIPU copolymers were evaluated using 1H nuclear magnetic resonance, Fourier transform infrared spectroscopy, gel permeation chromatography, thermogravimetric analysis, and differential scanning calorimetry measurements. All synthesized NIPUs were amorphous and exhibited good Td−5% thermal stabilities above 250°C; Tg decreased from 73 to 51°C as C36DDA content increased from 0% to 10% based on dynamic mechanical analysis tests. Furthermore, ethylenediamine (EDA) as a chain extender incorporating a small amount of crosslinker 1,2,4,5‐benzenetetracarboxylic acid (PMA) can enhance the melt strength of a partially three‐dimensional network, and the attained NIPU showed elastic properties. Thus, the NIPU synthesized with 7.5% and 10% C36DDA containing small amounts of EDA and PMA were suitable choices for supercritical CO2 foaming; their morphologies and mechanical behaviors were examined by scanning electron microscopy and DMA, and the densities of foamed NIPU with 7.5% and 10% C36DDA were calculated as 432 and 215 kg m−3 with pore sizes of 10–20 μm, respectively. The maximum stresses were attained at 149.5 and 123.4 kPa, and the foamed NIPU displayed rigid foam behaviors owing to the compression behaviors of the stress–strain curves. [ABSTRACT FROM AUTHOR]

The solvent‐free self‐healable waterborne poly(urethane‐urea) (SH‐WPU) product is environmentally friendly due to its lower volatile organic compounds emission during the coating process. This research revealed a strategy for breathable textile coating, that longer product life of SH‐WPU coated fabric based on the self‐healing dynamics that triggered by disulfide bond rearrangement upon temperature elevation (e.g., textile ironing). SH‐WPU was synthesized with 4,4′‐methylenebis cyclohexyl isocyanate as hard segment, (poly(propylene oxide)‐b‐poly (ethylene oxide)‐b‐poly (propylene oxide) triblock copolymer as soft segment. 4,4'‐Dithiodianiline (DTDA), and 2,2‐bis(hydroxymethyl)butyric acid were used as the chain‐extenders. The self‐healing efficiency was tested by simulated ironing condition. The SH‐WPU that contained 7.5 wt% of DTDA shown the highest recovery efficiency of stress at break by tensile test. The SH‐WPU coated fabric showed excellent recovery with the DTDA concentration from 4.5 to 7.5 wt% by the water pressure resistance test by disulfide and hydrogen bond rearrangement at elevated temperature. The results indicated the promising potential of SH‐WPU for breathable textile coating applications to not only overcome the damage under extreme weather conditions but also render the textile repairable by ironing. [ABSTRACT FROM AUTHOR]

Bis(6‐aminohexyl) terephthalamide/adipic acid (BAHT‐AA) was chosen to be used as a comonomer to develop a novel polyamide 6 (PA6) with the trace‐content aromatic structure. A series of polyamide 6 copolymers (coPA6) with trace BAHT‐AA loading were synthesized to yield the modified copolyamides with multiple interactions of hydrogen bonding and π‐π stacking on the PA6 backbone. It was proved that the thermal stability and mechanical properties of coPA6 were significantly enhanced because of the introduction of the trace BAHT‐AA segment. More importantly, adding a trace (1, 2, and 4 mole%) of BAHT‐AA could effectively increase the network structure and highly decrease the free volume fraction in the polymer system that is proved by the relaxation behavior and melt viscoelastic behavior. The results showed that the integrated performances of coPA6 were better than that of pure PA6, which was highly correlated with the aforementioned multiple interactions. For example, outstanding tensile strength (73.0 vs. 56.8 MPa), and modulus (1167 vs. 929 MPa), and so on. This work provided the traditional PA6 with the modification of outstanding mechanical and thermal performances, thus expanding its application for the plastics and textile industries. [ABSTRACT FROM AUTHOR]

A series of multiblock copolymers poly(ethylene terephthalate)‐co‐poly(ethylene glycol)‐poly(propylene glycol)‐poly(ethylene glycol) (PET‐X%‐E‐P‐E) were synthesized from dimethyl terephthalate (DMT), ethylene glycol (EG) and poly(ethylene glycol)‐poly(propylene glycol)‐poly(ethylene glycol) (E‐P‐E) with a two‐step procedure via melt polymerization. The structure, composition, crystallization behavior, and thermal stability of the synthesized copolymers were determined by 1H‐NMR, FT‐IR, XRD, DSC, and TGA measurements. All samples exhibited good thermal stability at a Td‐5% above 300°C. DSC results revealed an increment trend of crystallization ability of copolymers in lower E‐P‐E content and then decreased when E‐P‐E concentration gradually raised to 40 wt%. Furthermore, the mechanical properties of copolymers were investigated systematically; the incorporation with E‐P‐E segments significantly enhanced the toughness and water absorption ability. Impact strength increased from 670.46 to 4448.75 J/m2, and water absorption values raised from 0.7% to 3.4% of the content of E‐P‐E increased. The stress–strain curve exhibited that tensile strength reduced from 40.38 to 17.88 MPa, the elongation at break increased from 4.6 to 27.9%. These new tough PET materials have an important application in toughness polyester fiber by the melt‐spinning techniques. [ABSTRACT FROM AUTHOR]

A green approach for the synthesis of bio‐based polyamides (PAs) with a new macromolecular structure was developed. These bio‐based PAs were synthesized by solvent and catalyst‐free polycondensation combining fatty dimer acid Pripol™ 1009 with new difunctional aminoamides (DAAs). The later DAAs building blocks were synthesized by aminolysis of renewable dimethyl sebacate (DMS) and dimethyl adipate (DMA) with three different aliphatic diamines having diverse chain lengths, 2, 4, and 6 carbons. Bio‐based PAs showed Mw up to 30,581 g/mol, initial thermal degradation over 380°C, Tm from 168.3–202.4°C, Tg from 28.3–37.5°C, strain from 36.4 ± 4.0–313.5 ± 2.0%, and tensile strength up to 27.4 ± 0.1 MPa. Interestingly, all the PAs films had excellent optical transparency with cut‐off wavelengths of 276.0–283.0 nm, transmittance from 82.7%–90.7% at 600 nm. As a proof‐of‐concept of their usage, one of the PA was shown to be form microcellular foam by the green scCO2 method. The foams possessed uniform (cell size; 40 μm, foam density; 0.265 g/cm3, expansion rate; 7.2) and bimodal (cell size; 24/38 μm, foam density; 0.302 g/cm3, expansion rate; 6.5) cell textures depending on their foaming temperatures. This is the first report of bio‐based PA foams and transparent films manufacturing without toxic solvents. [ABSTRACT FROM AUTHOR]

As an environmental‐friendly coating material in industry, waterborne polyurethane–urea (WPU) is still not comparable with solvent‐based polyurethane (SPU) in mechanical properties, due to the hydrophilic chain‐extender. Herein, a synthetic scheme to increase the abrasion resistance of WPU with ether diol, and conventional hydrophilic chain‐extender (DMBA, 2,2‐bis[hydroxymethyl]butanoic acid) is revealed. This study discuss the degree of micro‐phase separation (DPS) with toughness, elongation, abrasion resistance, and compared with the WPU contain various types of diol, such as esters, ether and carbonates, and the ether‐based SPU. From the results, the major factor that affect to the abrasion properties of WPU is DPS, which is highly depend on the chemical structure of diol, and hard segment content. WPU film achieve higher toughness with ether‐based diol with higher DPS, and better abrasion resistance than SPU. This study demonstrate a strategy for the composition designing, and the synthesis of high‐abrasion resistance WPU by controlling the micro‐phase separation, and content of DMBA without any inorganic fillers. [ABSTRACT FROM AUTHOR]

Abstract: Synthesis of nanomaterials using cheap and highly efficient material is an important aspect of nanotechnology. In this present work, we have used the carbon black (CB) as a highly conductive and inexpensive carbonaceous material for the fabrication of the electrochemical sensor. However, the poor dispersion in water obstructs the usage of CB in electrochemical sensor and biosensor applications. Hence, the CB was functionalized by simple reflux method and the functionalized CB (f‐CB) nanospheres hybrids with hydrothermally synthesized MoS2 nanoclusters by simple ultrasonication process. In addition, the various suitable spectrometric techniques used to probe the surface morphology and chemical modification of the prepared materials. The prepared MoS2 and f‐CB nanohybrids (f‐CB/MoS2) applied for the electrocatalytic reduction of toxic chloramphenicol (CAP). Fascinatingly, the f‐CB/MoS2 modified electrode showed a competitive electrocatalytic performance comparing with other modified electrodes. At the optimized condition, the sensor exhibited the LOD about 0.002 μM, wider linear range 0.015 to 1370 μM with the sensitivity of 3400 μA μM−1 cm−2 for the determination of CAP. Moreover, the practical viability of the sensor was exploited in milk powder and honey samples. [ABSTRACT FROM AUTHOR]

In this study, we prepared a series of thermosensitive polymers with low polydispersity index (PDI) values by nitroxidemediated controlled radical polymerization (NMRP) with 2,2,6,6-tetramethyl-1-piperdinyloxy nitroxide (TEMPO) as a stable nitroxide-free radical. Poly(N-isopropyl acrylamide) (PNIPAAm)-block-poly(N-tert-butyl acrylamide) (PNTBA) was successfully synthesized, first, through polymerization with N-isopropyl acrylamide to obtain the reactive polymer PNIPAAm-TEMPO and, second, through polymerization by the addition of N-tert-butyl acrylamide (NTBA). The added molar fraction of NTBA during the second polymerization was adjusted accordingly to obtain the final polymerization product, a thermosensitive polymer (PNIPAAm-block- PNTBA), which had a targeted lower critical solution temperature (LCST). The result shows that the synthesis method used in this study effectively controlled the formation of the polymer to obtain a low PDI. The thermosensitive block copolymer, PNIPAAm-b- PNTBA (molar ratio = 9:1), with LCSTs in the range 27.7-39.8°C, was obtained through controlled living radical polymerization with PNIPAAm-TEMPO. Specifically, the 5 wt % aqueous solution of PNIPAAm-b-PNTBA (molar ratio = 9:1) had an LCST of 37.4°C; this was close to body temperature, 37°C. The 5 wt % aqueous solution of PNIPAAm-b-PNTBA (molar ratio59:1) showed potential for use in biomedical applications. [ABSTRACT FROM AUTHOR]

ABSTRACT Poly( N-isopropylacrylamide) (NIPAAm) is well known as a smart material with good thermal sensitivity and favorable biocompatibility. A series of new smart hydrogels, NIPAAm copolymerized with IAM (itaconamic acid; 4-amino-2-methylene-4-oxobutanoic acid), were synthesized through radical solution polymerization in this work. Poly(NIPAAm- co-IAM) can respond to the changes of temperature as well as pH value. Such a characteristic is due to the fact that IAM contains not only a hydrophilic acrylic acid moiety but also an acrylamide moiety to be thermal and pH sensitive. The experimental results show that the lower critical solution temperature (LCST) of the copolymer increases as the molar fraction of IAM increases. Moreover, based on the current experimental data, 3 wt % of Poly(NIPAAm- co-IAM) aqueous solution in this study exhibits a phase transition temperature (37.8°C) close to the human body temperature in the buffer solution of pH 7 possibly to be useful in drug delivery. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42367. [ABSTRACT FROM AUTHOR]

A series of poly(ethylene oxide) (PEO) and nylon-6 copolymers were synthesized through condensation reactions. The rheology of the prepared copolymers was tested using a capillary flow rheometer. The molar mass was investigated by performing basic analyses such as relative viscosity, gel permeation chromatograph, and amino-end group analysis. Their thermal properties were examined by differential scanning calorimetry, and the crystalline structure was determined using wide-angle X-ray diffraction. The results obtained from partially oriented yarn indicated a dramatically conversion from the γ form to the α form. Following the draw texture process, the α form dominated all draw textured yarn. Once the segments of PEO were introduced into the nylon-6 backbone, the moisture regain and qmax (warm/cool feeling) of the fabrics was enhanced remarkably. The surface resistivity of fabrics improved with increasing PEO content, which is mainly due to water absorption. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]

The heterojunction of poly(3-hexylthiophene) (P3HT) and TiO2 in hybrid solar cells is systematically engineered with four cyanoacrylic acid-containing conjugated molecules with various lowest unoccupied molecular orbital (LUMO) levels, WL-1 to WL-4, which are prepared by the formylation of thiophene derivatives in a Vilsmeier-Haack reaction, followed by treatment with cyanoacetic acid. The optical characteristics, redox properties, and intrinsic dipole moments of these interfacial modifiers (IMs) are examined using UV-vis spectrophotometry, cyclic voltammetry, and density functional theory calculations. Using cyanoacrylic acid as a terminal anchoring group in IMs increases the electron affinity in regions close to the titania surface and forms a molecular dipole that is orientated away from the TiO2 surface, enabling both open-circuit voltage ( VOC) and short-circuit current density to be increased simultaneously. Photovoltaic measurements demonstrate that VOC increases with the dipole moment of IMs along the molecular backbone. Moreover, the external quantum efficiency (EQE) spectra display a bimodal distribution, revealing that both IMs and P3HT contribute to the photocurrent. The EQE at 570 nm is identified as characteristic of P3HT. More importantly, the LUMO of the IMs decisively determines the dissociation efficiency of P3HT excitons. The device based on P3HT/WL-4/TiO2 exhibits the highest power conversion efficiency of 2.87%. [ABSTRACT FROM AUTHOR]

In this work, we have synthesis nylon-6/polyethylene oxide (PEO) copolymer system based on feed ratio of PEO (0∼ 10 wt %) through condensation polymerization in a pilot scale. The structure of copolymer was confirmed by Fourier transform infrared (FTIR) spectroscopy and verified by 1H nuclear magnetic resonance (1HNMR). The thermal properties were investigated by differential scanning calorimetry (DSC) and indicated both melting temperature ( T m) and cold crystallization temperature ( T c) appearing unapparent decreased while increased PEO content in copolymers. The incorporation of PEO into the nylon-6 chain reduced its tensile strength, modulus, and heat distortion temperature (HDT). The notched Izod impact strength of and ductility of the copolymers improved significantly as the PEO content was increased. The plasticizing effect was caused by the soft segments from PEO, which increases the mobility of the molecular chain in the copolymers. The results of mechanical tests agree closely with dynamic mechanical analysis (DMA) measurements. A rheological investigation revealed that neat nylon-6 and its copolymer displayed similar behavior. The crystalline structure was examined by wide-angle X-ray diffraction (WAXD). The results demonstrate that the addition of a little PEO altered the crystallization from the α form to the γ form, mainly owing to the breaking parts of the original H-bonds by the incorporation of ether groups. A mechanism of interaction between the amide and the ether group in nylon-6/PEO copolymers is proposed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 [ABSTRACT FROM AUTHOR]

Provides information on a study which investigated the effects of polyethylene naphthalate on the high speed spinning process of polyethylene terephthalate extrusion. Experimental procedures; Results and discussion; Conclusion.

Presents an experiment which focused on the properties of blends of poly(ethylene terephthalate) (PET) as the majority component and poly(ethylene naphthalate) (PEN) as the minority component. Experimental procedures; Results and discussion; Conclusions.

Investigates the dog-legging mechanism in a melting process under various spinning conditions. Information on the spinning of PP, PET, and PEN fibers; Details on the primary cause of bending in the spinline; Discussion on the process which caused the binding angle to increase; Information on final results obtained.

Due to increasing environmental concerns and depletion of petroleum resources, the use of green materials has become popular with garment industry. In the past, natural rubber, which is one of the most prevalent bio‐based elastomers, was used as waterproof coating for many applications due to its inherent elasticity, high tear and abrasion resistance, and hydrophobicity. However, NR has significant drawbacks when applying to garments including its poor adhesion to polyester fabrics and low breathability. Polyurethane, on the other hand, possesses high breathability but relatively poor elasticity. In this study, the fabric coating based on waterborne polyurethane and pre‐vulcanized natural rubber latex was synthesized with the goal to produce fabric for high‐performance applications, which could surpass criteria including water vapor permeability (WVP) (>10 000 g/m2•24hr), water pressure resistance (WPR) (>1000 mmH2O), and stretchability (>300%). The best condition achieved when using 60NR cured for 15 min by using 1.5 phr sulfur could provide WPR value of 4090 mmH2O and WVP of 11 033 g/m2•24hr. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48002. [ABSTRACT FROM AUTHOR]

In this study, materials with low melting temperatures and high toughness are developed for orthopedic applications. A series of an aliphatic copolyester based on sebacic acid (SeA), a green resource, is copolymerized with ethylene glycol, trimesic acid, aminocaproic acid, and adipic acid (AA) to produce poly(ethylene sebacate‐co‐ethylene adipate) (PESA) with various molar ratios through melt polymerization. Thermal characterizations of the PESA copolyesters are tuned with SeA and AA in varying molar ratios, exhibiting a crystalline phase with a lower degree of perfection. The melting point (Tm) and crystallization temperature (Tc) of the copolyesters are observed at 60–70 and 30–40 °C, respectively. Furthermore, a high Young's modulus ranging between 140 and 200 MPa is observed, which could be attributed to the 3D network structure formed by the trimesic acid unit used as a cross‐linking agent. Within the authors' research group, the PESA copolyesters are adopted to reinforce the mechanical properties of a 3D air mesh fabric as a composite application. Also, the highly breathable and low‐weight characteristics of 3D fabric with PESA copolyesters render them suitable for replacing traditional plaster in the future. [ABSTRACT FROM AUTHOR]