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The search for alternatives to petroleum-based thermoplastic polyamide elastomers (TPAEs) has recently drawn great interest. In this study, a bio-massed TPAE, PA12,36, was synthesized using 1,12-dodecanediamine (DDA) and fatty dimer acid (FDA, PripolTM1009) precursors via catalyst and solvent-free melt polycondensation. The molecular structure and molecular weight of the PA12,36 were characterized by 1H NMR, FTIR, and GPC. PA12,36 displayed a low melting temperature of 85.8 °C, an initial degradation temperature of 425 °C, and a glass-transition temperature of 30.4 °C, whereas it sustained satisfactory tensile strength (10.0 MPa) and superior strain at break (1378%). Furthermore, PA12,36 was foamed by supercritical CO2, and the cell size, cell density, and porosity were determined. The entangled long-chained FDA component generated a physically crosslinked network, which promoted the melt viscosity of PA12,36 against elongations of foam cell growth and increased foamability significantly. As a result, uniform structured cellular foams with a cell diameter of 15–24 µm and high cell density (1011 cells/cm3–1012 cells/cm3) were successfully achieved. The foaming window was widened from 76 to 81 °C, and the expansion ratio was increased from 4.8 to 9.6. Additionally, PA12,36 foam with a physically crosslinked structure presented a better creep shape recovery percentage (92–97.9%) and sturdier dimensional stability. This bio-based PA12,36 foam is a promising candidate to replace petroleum-based thermoplastic elastomer foams for engineering applications, particularly shoe soles. [ABSTRACT FROM AUTHOR]

9,9-bis[4-(2-hydroxy-3-acryloyloxypropoxy)phenyl]fluorene (BPF) hydroxyl groups (-OH) were used as initiators in the ring-opening polymerization reaction with DL-lactide monomers at different molar ratios to synthesize a Poly(DL-lactide) polymer containing bisphenol fluorene structure and acrylate functional groups (DL-BPF). The polymer's structure and molecular weight range were analyzed using NMR (1H, 13C) and gel permeation chromatography. DL-BPF was then subjected to photocrosslinking using the photoinitiator Omnirad 1173, resulting in the formation of an optically transparent crosslinked polymer. Characterization of the crosslinked polymer involved analyzing its gel content, refractive index, thermal stability (via differential scanning thermometry (DSC) and thermogravimetric analysis (TGA)), as well as conducting cytotoxicity tests. The crosslinked copolymer exhibited a maximum refractive index of 1.5276, a maximum glass transition temperature of 61.1 °C, and cell survival rates higher than 83% in the cytotoxicity tests. [ABSTRACT FROM AUTHOR]

PCL-based biodegradable shape-memory polymers (SMPs) are limited in strength, which restricts their practical applications. In this study, a series of novel SMPs, composed of poly(ethylene terephthalate) (PET), poly(ethylene naphthalate) (PEN), and poly(ε-caprolactone) (PCL), were synthesized and cross-linked using planar (benzene-1,3,5-tricarboxylic acid, BTC) or non-planar (glycerol, GC) cross-linkers via the one-pot method. The influence of different kinds of cross-linkers and hard segments of copolyesters on the thermal properties, crystallization behavior, mechanical properties, shape-memory performance, and degradability was investigated by FT-IR, 1H-NMR, DSC, DMA, TGA, XRD, tensile test, intrinsic viscosity measurement, and in vitro enzymatic degradation test. The results indicate that the tensile strength of the copolyester can be significantly improved from 27.8 to 53.2 MPa by partially replacing PET with PEN while maintaining its shape-memory characteristics. Moreover, a small amount of cross-linking modification leads to higher temperature sensitivity, improved shape recovery rate at third round (Rr(3) = 99.1%), and biodegradability in the cross-linked PET/PEN/PCL shape-memory polymers. By changing the crystallization morphology and cross-linking forms of the material, we have developed a shape-memory polymer with both high strength and a high shape recovery rate, which provides a new strategy for the development of shape-memory materials. [ABSTRACT FROM AUTHOR]

A series of poly(butylene adipate-co-hexamethylene adipate) (PBHA) copolymers with different content of 1,4-cyclohexanedimethanol (CHDM) was synthesized via one-step melt polymerization. The PBHA copolymer with 5 mol% CHDM (PBHA-C5) exhibited a low melting point (Tm) and high enthalpy of fusion (∆Hm) of 35.7 °C and 43.9 J g−1, respectively, making it a potential candidate for an ambient temperature adjustment textile phase change material (PCM). Polybutylene terephthalate (PBT) was selected as the matrix and blended at different weight ratios of PBHA-C5, and the blended samples showed comparable Tm and ∆Hm after three cycles of cooling and reheating, indicating good maintenance of their phase changing ability. Samples were then processed via melt spinning with a take-up speed of 200 m min−1 at draw ratios (DR) of 1.0 to 3.0 at 50 °C. The fiber's mechanical strength could be enhanced to 2.35 g den−1 by increasing the DR and lowering the PBHA-C5 content. Infrared thermography showed that a significant difference of more than 5 °C between PBT and other samples was achieved within 1 min of heating, indicating the ability of PBHA-C5 to adjust the temperature. After heating for 30 min, the temperatures of neat PBT, blended samples with 27, 30, and 33 wt% PBHA-C5, and neat PBHA-C5 were 53.8, 50.2, 48.3, 47.2, and 46.5 °C, respectively, and reached an equilibrium state, confirming the temperature adjustment ability of PBHA-C5 and suggesting that it can be utilized in thermoregulating applications. [ABSTRACT FROM AUTHOR]

The pre-experiment of the present study revealed that polyurethane (PU) synthesized using poly (hexamethylene carbonate) glycol (PHC) has high melt viscosity and is difficult to process. Therefore, poly (trimethylene carbonate) glycol (PTC) was employed to synthesize a PU product with low melt viscosity. First, four types of thermoplastic polyurethane (TPU) were formed through one-step solvent-free synthesis. TPU is presented in the format "TPU-X-Y," with X representing the polyol (PTC or PHC, around 1000 molecular weight) and Y the chain extender (1,3-propane diol [PDO] or 1,4-butane diol [BDO]) used. The TPU was synthesized using a fixed molar ratio of (isocyanate):(polyol):(chain extender) = 2:1:1 and compared. The results indicated that chain entanglement often occurred among the long carbon chains of PHC. The synthesized TPU employed a property of PTC, namely converting polarity into reverse polarity in high temperatures, to resolve the high melt viscosity of TPU of the PHC series, which causes processing difficulties. The synthesized TPU-PTC-PDO exhibited favorable molecular arrangements. Given its polarity, TPU-PTC-PDO has outstanding tensile properties (strength at break: 41.10 ± 10.78 MPa; 100% modulus = 6.73 ± 0.12 MPa), making processing at lower temperatures (180 or 190 °C) feasible. With the inclusion of PTC, the synthesized polycarbonate TPU exhibits the advantages of polycarbonate and is suitable for a wide range of applications. [ABSTRACT FROM AUTHOR]

In this study, when deriving thermoplastic polyurethane (TPU), the researchers replaced 1,4-butanediol (1,4-BDO) with 1,3-butanediol (1,3-BDO) as a chain extender and examined how the structure of the chain extender affected the final polymers. Regarding the raw materials for polymerization, three types of commercial polyols with the same molecular weight (Mn = 1000 g/mol), namely, poly (butyl acrylate) (PBA), poly (tetramethylene ether) glycol (PTMG), and polycarbonate diol (PCDL) were used. These polyols were used in conjunction with butanediol and 4,4'-methylene diphenyl diisocyanate. Three groups of TPUs were successfully synthesized using one-shot solvent-free bulk polymerization. Compared with TPUs polymerized using 1,4-BDO, materials polymerized using 1,3-BDO are more transparent and viscous. Structural analysis revealed that no substantial differences between the final structures of the TPUs were present when different chain extenders were used. Thermal analysis indicated that compared with TPUs polymerized using 1,4-BDO, the glass transition temperature of those with 1,3-BDO was 15 °C higher. Examination of microphase separation in the structure by using morphological analysis revealed that compared with TPUs synthesized using 1,4-BDO, PBA, and PTMG synthesized using 1,3-BDO were relatively separated. PCDL synthesized using 1,3-BDO exhibited no morphological difference. Rheological analysis indicated PCDL synthesized using either 1,4-BDO or 1,3-BDO did not exhibit any obvious differences. In conclusion, TPUs synthesized using PCDL and 1,3-BDO exhibited thermal plasticity at room temperature (15–20 °C). Their basic application could be extended to the development of smart materials. In terms of further application, they could be used in shape memory and temperature-sensitive high molecular polymers. [ABSTRACT FROM AUTHOR]

In this study, we report a novel approach to fabricate an organic/inorganic magnetic hybrid system capable of self-healing, wherein a polycaprolactone-poly(furfuryl glycidyl ether) copolymer (PCLF) serving as the structure template was first synthesized, followed by the incorporation of iron oxide nanoparticles-decorated multiwalled carbon nanotubes (IONPs-MWCNTs) and 1,1′-(methylenedi-4,1-phenylene)bismaleimide (BMI) into the polymer matrix to form a covalently crosslinked hybrid network via a Diels−Alder (DA) reaction. For this system, the reactive combination of diene and dienophile from furan/maleimide, MWCNT/furan, and MWCNT/maleimide could facilely induce multiple DA reactions that imparted a versatile route to efficiently introduce IONPs-MWCNTs into the organic polymer hosts, resulting in a uniform distribution of IONPs-MWCNTs that led to a hybrid system with superparamagnetic properties. Beside the magnetic behavior, such material synergistically exhibited a superior ability for healing scratch defects via a retro-DA reaction. Therefore, this crosslinked PCLF/BMI/IONPs-MWCNTs hybrid system which exhibits multifunctional properties including superparamagnetic behavior and self-repairability can serve as an intelligent material for developing advanced electromagnetic applications. [ABSTRACT FROM AUTHOR]

In this work, the development and application of multicomponents obtained from recycled polyethylene terephthalate (r-PET) waste and monotropic liquid crystals as anticorrosion coatings are reported. The r-PET raw material was alcoholyzed and reproduced as a thermoplastic polyester elastomer (TPEE) with different amounts (n%, n = 0, 1, 3, and 5) of 1,6-hexanediamine (HDA). Then, a fluorine-containing liquid crystal (4-cyano-3-fluorophenyl 4-ethylbenzoate (4CFE)) was incorporated into the TPEE mixture via solvent blending to modify and enhance the water resistance. The adhesion behavior of the coating on glass and iron substrates was evaluated by cross-cut tests and immersion tests in aqueous NaCl. In the corrosion resistance measurements, all of the coating samples fabricated with 10 ± 1 mm thickness were less active toward electrochemical corrosion (PEF% > 99%) than the bare iron plate, indicating that our work provided better protection against corrosion of the iron plate. [ABSTRACT FROM AUTHOR]

Renewable polymers with self-healing ability, excellent elongation, hydrophobicity, and selective oil absorption attributes are of interest for an extensive range of applications, such as e-skin, soft robots, wearable devices, and cleaning up oil spills. Herein, two fully renewable eco-friendly polyamide (PA)-based self-healing elastomers (namely, PA36,IA, and PA36,36) were prepared by a facile and green one-pot melt polycondensation of itaconic acid (IA), PripolTM 1009, and PriamineTM 1075 monomers. The molecular structures of these PAs were analyzed by FITR, 1H NMR, and 13C NMR. The distinct structure of these PAs shows superior strain values (above 2300%) and high ambient temperature autonomous self-healing ability. Interestingly, the synthesized renewable PA36,36 showed zero water absorption values and hydrophobic properties with a contact angle of θ = 91° compared to the synthesized PA36,IA and other previously reported PAs. These excellent attributes are due to the low concentration of amide groups, the highly entangled main chains, the intermolecular diffusion, the manifold dangling chains, and the numerous reversible physical bonds within the renewable PAs. Furthermore, the hydrophobic properties may aid in the selective oil absorption of the PA36,36-based foam, for which PA36,36 foam is produced by the green supercritical carbon dioxide (scCO2) batch foaming process. The PA36,36 foam with a microporous cellular structure showed better absorption capacity and high stability in repeated use. Due to these advantages, these bio-based PAs have potential for the production of eco-friendly self-healing materials, superabsorbent foams, and other polymeric materials. [ABSTRACT FROM AUTHOR]

Human safety, health management, and disease transmission prevention have become crucial tasks in the present COVID-19 pandemic situation. Masks are widely available and create a safer and disease transmission–free environment. This study presents a facile method of fabricating masks through electrospinning nontoxic polyvinyl butyral (PVB) polymeric matrix with the antibacterial component Thymol, a natural phenol monoterpene. Based on the results of Japanese Industrial Standards and American Association of Textile Chemists and Colorists methods, the maximum antibacterial value of the mask against Gram-positive and Gram-negative bacteria was 5.6 and 6.4, respectively. Moreover, vertical electrospinning was performed to prepare Thymol/PVB nanofiber masks, and the effects of parameters on the submicron particulate filtration efficiency (PFE), differential pressure, and bacterial filtration efficiency (BFE) were determined. Thorough optimization of the small-diameter nanofiber–based antibacterial mask led to denser accumulation and improved PFE and pressure difference; the mask was thus noted to meet the present pandemic requirements. The as-developed nanofibrous masks have the antibacterial activity suggested by the National Standard of the Republic of China (CNS 14774) for general medical masks. Their BFE reaches 99.4%, with a pressure difference of <5 mmH2O/cm2. The mask can safeguard human health and promote a healthy environment. [ABSTRACT FROM AUTHOR]

The development of nontoxic and biodegradable alginate-based materials has been a continual goal in biological applications. However, their hydrophilic nature and lack of spinnability impart water instability and poor mechanical strength to the nanofiber. To overcome these limitations, sodium alginate (SA) and waterborne polyurethane (WPU) were blended and crosslinked with calcium chloride; 30 wt % of SA exhibited good compatibility. Further addition of 10 wt % calcium chloride improved the water stability to an extremely humid region. Furthermore, the stress–strain curve revealed that the initial modulus and the elongation strength of the WPU/SA and WPU/CA blends increased with SA content, and the crosslinker concentration clearly indicated the dressing material hardness resulted from this simple blend strategy. The WPU/SA30 electrospun nanofibrous blend contained porous membranes; it exhibited good mechanical strength with water-stable, water-absorbable (37.5 wt %), and moisture-permeable (25.1 g/m2–24 h) characteristics, suggesting our cost-effective material could function as an effective wound dressing material. [ABSTRACT FROM AUTHOR]

Bio-based unsaturated poly(butylene adipate-co-butylene itaconate) (PBABI) aliphatic copolyesters were synthesized with pentaerythritol (PE) as a modifier, observing the melting point, crystallization, and glass transition temperatures were decreased from 59.5 to 19.5 °C and 28.2 to −9.1 °C as an increase of itaconate concentration, and Tg ranged from −54.6 to −48.1 °C. PBABI copolyesters tend to the amorphous state by the existence of the BI unit above 40 mol%. The yield strength, elongation, and Young's modulus at different BA/BI ratios were valued in a range of 13.2–13.8 MPa, 575.2–838.5%, and 65.1–83.8 MPa, respectively. Shear-thinning behavior was obtained in all BA/BI ratios of PBABI copolyesters around an angular frequency range of 20–30 rad s−1. Furthermore, the thermal and mechanical properties of PBABI copolyesters can be well regulated via controlling the itaconic acid contents and adding the modifier. PBABI copolyesters can be coated on a 3D air mesh polyester fabric to reinforce the mechanical property for replacing traditional plaster applications. [ABSTRACT FROM AUTHOR]

Poly(butylene terephthalate-co-tetramethylene ether glycol) (PBT-co-PTMEG) copolymers with PTMEG ranging from 0 to 40 wt% were synthesized through melt polymerization. The structure and composition were supported by Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (1H NMR). All samples had excellent thermal stability at a Td−5% around 370 °C. Crystallization temperature (Tc) and enthalpy of crystallization (ΔHc) were detected by differential scanning calorimetry (DSC), revealing a decrement from 182.3 to 135.1 °C and 47.0 to 22.1 J g−1, respectively, with the increase in PTMEG concentration from 0 to 40 wt%. Moreover, nonisothermal crystallization was carried out to explore the crystallization behavior of copolymers; the crystallization rate of PBT reduced gradually when PTMEG content increased. Hence, a decrement in the spherulite growth rate was detected in polarizing light microscope (PLM) observation, observing that the PTMEG could enhance the hindrance in the molecular chain to lower the crystallinity of PBT-co-PTMEG copolyester. Moreover, thermal properties and the crystallization rate of PBT-co-PTMEG copolymers can be amended via the regulation of PTMEG contents. [ABSTRACT FROM AUTHOR]

Unsaturated poly (butylene adipate-co-butylene itaconate) (PBABI) copolyesters were synthesized through melt polymerization composed of 1,4-butanediol (BDO), adipic acid (AA), itaconic acid (IA) and 1,2,4,5-benzenetetracarboxylic acid (BTCA) as a cross-linking modifier. The melting point, crystallization and glass transition temperature of the PBABI copolyesters were detected around 29.8–49 °C, 7.2–29 °C and −51.1 and −58.1 °C, respectively. Young's modulus can be modified via partial cross-linking by BTCA in the presence of IA, ranging between 32.19–168.45 MPa. Non-isothermal crystallization kinetics were carried out to explore the crystallization behavior, revealing the highest crystallization rate was placed in the BA/BI = 90/10 at a given molecular weight. Furthermore, the thermal, mechanical properties, and crystallization rate of PBABI copolyesters can be tuned through the adjustment of BTCA and IA concentrations. [ABSTRACT FROM AUTHOR]

The crystallization behavior of novel polyamide 6 (PA6) copolyamides with different amounts of bis (2-aminoethyl) adipamide/adipic acid (BAEA/AA) segment was investigated. The wide-angle X-ray diffraction (WAXD) results showed that as the amount of BAEA/AA segment increased to 10 mole%, the crystalline forms of all PA6 copolyamide were transferred from the stable α-form to the unstable γ-form because of the complex polymer structure. According to studies of crystallization kinetics, the Avrami exponent (n) values for all copolyamide samples ranged from 1.43 to 3.67 under isothermal conditions, implying that the crystallization is involved in the two- to three-dimensional growth at a high temperature of isothermal condition. The copolyamides provided a slower crystallization rate and higher crystallization activation energy (ΔEa) than neat PA6. Polyamide containing 10 mole% of BEAE/AA content exhibited a unique crystallization behavior in the coexistence of the α and γ forms. These results deepen our understanding of the relationship between BAEA/AA content, crystal structure, and its crystallization behavior in low-melting PA6, and they make these types of copolyamides useful for their practical application. [ABSTRACT FROM AUTHOR]

In this study, a novel biobased poly(ethylene brassylate)-poly(furfuryl glycidyl ether) copolymer (PEBF) copolymer was synthesized and applied as a structure-directing template to incorporate graphene and 1,1′-(methylenedi-4,1-phenylene)bismaleimide (BMI) to fabricate a series of self-healing organic/inorganic hybrid materials. This ternary material system provided different types of diene/dienophile pairs from the furan/maleimide, graphene/furan, and graphene/maleimide combinations to build a crosslinked network via multiple Diels–Alder (DA) reactions and synergistically co-assembled graphene sheets into the polymeric matrix with a uniform dispersibility. The PEBF/graphene/BMI hybrid system possessed an efficient self-repairability for healing structural defects and an electromagnetic interference shielding ability in the Ku-band frequency range. We believe that the development of the biobased self-healing hybrid system provides a promising direction for the creation of a new class of materials with the advantages of environmental friendliness as well as durability, and shows potential for use in advanced electromagnetic applications. [ABSTRACT FROM AUTHOR]

A series of copolyesters, poly(butylene adipate-co-butylene itaconate) (PBABI), was synthesized using melt polycondensation from adipic acid (AA), itaconic acid (IA), 1,4-butanediol (1,4-BDO), and ethylenediaminetetraacetic acid (EDTA). 1H-NMR, FT-IR, GPC, DSC, TGA, DMA, XRD, Shore D, and tensile test were used to systematically characterize the structural and composition/physical properties of the copolyesters. It was found that the melting point (Tm) and crystallization temperature (Tc) of the copolyesters were, respectively, between 21.1 to 57.5 °C and −6.7 to 29.5 °C. The glass transition (Tg) and the initial thermal decomposition (Td-5%) temperatures of the PBABI copolyesters were observed to be between −53.6 to −55.8 °C and 313.6 and 342.1 °C at varying ratios of butylene adipate (BA) and butylene itaconate (IA), respectively. The XRD feature peak was identified at the 2θ values of 21.61°, 22.31°, and 23.96° for the crystal lattice of (110), (020), and (021), respectively. Interestingly, Shore D at various IA ratios had high values (between 51.3 to 62), which indicated that the PBABI had soft plastic properties. The Young's modulus and elongation at break, at different IA concentrations, were measured to be at 0.77–128.65 MPa and 71.04–531.76%, respectively, which could be attributed to a close and compact three-dimensional network structure formed by EDTA as a crosslinking agent. There was a significant bell-shaped trend in a BA/BI ratio of 8/2, at different EDTA concentrations—the ∆Hm increased while the EDTA concentration increased from 0.001 to 0.05 mole% and then decreased at an EDTA ratio of 0.2 mole%. Since the PBABI copolymers have applications in the textile industry, these polymers have been adopted to reinforce 3D air-permeable polyester-based smart textile. This kind of composite not only possesses the advantage of lower weight and breathable properties for textiles, but also offers customizable, strong levels of hardness, after UV curing of the PBABI copolyesters, making its potential in vitro orthopedic support as the "plaster of the future". [ABSTRACT FROM AUTHOR]

N1, N6-bis (4-aminobutyl) adipamide (BABA) diamine and sebacic acid (SA), also called BABA/SA polyamide salt, were used in a typical melt polymerization processes of polyamide 6 (PA6) to form a series of PA6-BABA/SA copolyamides. The effects of BABA/SA on the isothermal crystallization kinetics of PA6-BABA/SA were studied for the first time. An isothermal crystallization analysis demonstrates that the PA6-BABA/SA matrix provided a higher crystallization rate and shorter half-crystallization time than virgin PA6 did. The degree of crystallization of the PA6-BABA/SA30 matrix was also the lowest among all of the samples considered herein. This result is attributed to the high nucleation efficacy of a small amount of BABA/SA in the crystallization of PA6. Values of the Avrami exponent (n) from 1.84 to 3.91 were observed for all of the polyamide samples, suggesting that the crystallization was involved via a two- to three-dimensional growth mechanism. These findings deepen our understanding of the structure–property relationship of PA6-BABA/SA copolyamides, favoring their practical application. [ABSTRACT FROM AUTHOR]

The conducting polymer of poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) is one of the most important and intensively investigated organic conducting materials. The PEDOT:PSS water dispersions with various concentrations of poly (4-styrenesulfonic acid) solution (PSSAS) were synthesized by 3,4-ethylenedioxythiophene (EDOT) in the presence of water. The fabrication of the solvent-treated PEDOT:PSS films through spin coating and solvent treatment processes was achieved with a solvent of pure water mixed with acetone (or MeOH, EtOH) in a ratio of 50:50. Moreover, both the organic solvent and water have synergetic effects while the PSS and PEDOT-attached PSS segments will form a coil-like and a linear (or extended-coil) structure, respectively. That may induce a stacking of the linear and planar PEDOT-attached PSS segments, which favors the formation of a crystalline phase. Finally, the maximum electrical conductivity of the PEDOT:PSS thin films with solvent treatment was investigated by means of X-ray diffraction (XRD) patterns and scanning electron microscope (SEM) images. Furthermore, we aimed to explain the synergetic effects of phase separation of the PEDOT:PSS thin films by both the organic solvent and water. [ABSTRACT FROM AUTHOR]

This work investigated the synthesis of a novel low melting temperature polyamide 6 (PA6) copolyamide (PA6-BABT/SA) with different aliphatic/aromatic units weight content using a melt poly-condensation process. The bio-based aromatic N1,N4-bis(4-aminobutyl) terephthalamide diamine (BABT) and long-chain aromatic polyamide salt (BABT/SA, salt of BABT, and sebacic acid), components used for the synthesis of copolyamides, were obtained from bio-based monomers. For the first time, the pertinent BABT/SA aromatic polyamide salt was isolated as a white solid and completely characterized. By varying the weight ratio of BABT/SA salt, a series of copolyamides with different molecular weights and physical properties were prepared. The aromatic BABT/SA salt disrupted crystallization of the final copolyamides and lowered the onset of melting. The Fourier transform infrared spectroscopy and X-ray diffraction results indicated a steady decrease in the degrees of crystallinity with increasing BABT/SA salt segment ratio. Furthermore, compared to neat PA6, the obtained PA6-BABT/SA copolymers possessed a similar thermal stability and high transparency, but lower glass transition temperature around human body temperature. The PA6-BABT/SA copolymers with number-average molecular weight ≥30,000 Da presented good mechanical properties, specifically showing excellent tensile strength and elongation at break up to 105.2 MPa and 218.3%, respectively. [ABSTRACT FROM AUTHOR]

Recycled waste industrial cellulose triacetate (TAC) film, which is one of the key materials in polarizers, was used to produce nanofiber membranes by electrospinning and synergistic assembly with graphene oxide (GO) and titanium dioxide (TiO2) for oil-water separation. In this study, GO and TiO2 coated by an electrophoretic deposition method introduced super hydrophilicity onto the recycled TAC (rTAC) membrane, with enhanced water permeability. The results indicate that when the outermost TiO2 layer of an asymmetric composite fiber membrane is exposed to ultraviolet irradiation; the hydrophilicity of the hydrophilic layer is more effectively promoted. Moreover, this coating could efficiently repel oil, and demonstrated robust self-cleaning performance during the cycle test, with the aid of the photocatalytic properties of TiO2. The rTAC membrane of networked hydrophobic fibers could also increase the speed of the filtrate flow and the water flux of the oil-water emulsion. The permeate carbon concentration in the water was analyzed using a total organic carbon analyzer. Incorporation of TiO2/GO onto the rTAC membrane contributed greatly towards enhanced membrane hydrophilicity and antifouling performance. Therefore, the novel TiO2/GO/rTAC asymmetric composite fiber has promise for applications in oil-water separation. [ABSTRACT FROM AUTHOR]

A series of semi-interpenetrating polymer network (semi-IPN) hydrogels were synthesized and investigated in this study. Linear copolymer poly(N-isopropylacrylamide-co-itaconamic acid) p(NIPAM-co-IAM), which is formed by copolymerization of N-isopropylacrylamide (NIPAM) and itaconamic acid (IAM, 4-amino-2-ethylene-4-oxobutanoic acid), was introduced into a solution of NIPAM to form a series of pH and thermo dual-responsive p(NIPAM-co-IAM)/pNIPAM semi-IPN hydrogels by free radical polymerization. The structural, morphological, chemical, and physical properties of the linear copolymer and semi-IPN hydrogels were investigated. The semi-IPN hydrogel showed high thermal stability according to thermal gravimetric analyzer (TGA). Scanning electronic microscopy (SEM) images showed that the pore size was in the range of 119~297 µm and could be controlled by the addition ratio of the linear copolymer in the semi-IPN structure. The addition of linear copolymer increased the fracture strain from 57.5 ± 2.9% to 91.1 ± 4.9% depending on the added amount, while the compressive modulus decreased as the addition increased. Moreover, the pH and thermo dual-responsive properties were investigated using differential scanning calorimetry (DSC) and monitoring the swelling behavior of the hydrogels. In deionized (DI) water, the equilibrium swelling ratio of the hydrogels decreased as the temperature increased from 20 °C to 50 °C, while it varied in various pH buffer solutions. In addition, the swelling and deswelling rates of the hydrogels also significantly increased. The results indicate that the novel pH-thermo dual-responsive semi-IPN hydrogels were synthesized successfully and may be a potential material for biomedical, drug delivery, or absorption application. [ABSTRACT FROM AUTHOR]

In this work, a smart copolymer, Poly(nipam-co-IAM) was synthesized by copolymerization of N-isopropylacrylamide (nipam) and itaconamic acid (IAM) through reversible addition-fragmentation chain-transfer (RAFT) polymerization. Poly(nipam-co-IAM) has been studied previously synthesized via radical polymerization without stereo-control, and this work used cumyl dithiobenzoate and Ytterbium(III) trifluoromethanesulfonate as RAFT and stereo-control agents, respectively. The stereo-control result in this work shows that tacticity affects the lower critical solution temperature (LCST) and/or the profile of phase separation of Poly(nipam-co-IAM). In the pH 7 and pH 10 buffer solutions, the P(nipam-co-IAM) copolymer solutions showed soluble–insoluble–soluble transitions, i.e., both LCST and upper critical solution temperature (UCST) transitions, which had not been found previously, and the insoluble to soluble transition (redissolved behavior) occurred at a relatively low temperature. The insoluble to soluble transition of P(nipam-co-IAM) in alkaline solution occurred at a temperature of less than 45 °C. However, the redissolved behavior of P(nipam-co-IAM) was found only in the pH 7 and pH 10 buffer solutions and this redissolved behavior was more prominent for the atactic copolymers than in the isotactic-rich ones. In addition, the LCST results under our experimental range of meso content did not show a significant difference between the isotactic-rich and the atactic P(nipam-co-IAM). Further study on the soluble-insoluble-soluble (S-I-S) transition and the application thereof for P(nipam-co-IAM) copolymers will be conducted. [ABSTRACT FROM AUTHOR]

Novel two-dimensional conjugated copolymer, abbreviated as PDTBSeVTT-2TF, containing electron-deficient 4,7-di(thiophen-2-yl)benzo[ c ][1,2,5]selenodiazole (DTBSe) unit, conjugated vinyl-terthiophene (VTT) side chain and 3,3'-difluoro-2,2'-bithiophene (2TF) was designed and synthesized using microwave-assisted Stille cross-coupling polymerization. UV⁻visible absorption and cyclic voltammetry studies revealed that this copolymer possesses a strong and broad absorption in the range of 300⁻800 nm and a narrow optical bandgap ( E g ) of 1.57 eV with low-lying HOMO and LUMO energy levels. Further, the bulk heterojunction polymer solar cells (PSCs) were fabricated using PDTBSeVTT-2TF as donor and [6,6]-phenyl-C 71 -butyric acid methyl ester (PC 71 BM) as acceptor with an inverted device structure of ITO/ZnO/PDTBSeVTT-2TF:PC 71 BM/V₂O₅/Ag. The processing temperature of blend solution for preparing PDTBSeVTT-2TF:PC 71 BM active layer showed obvious impact on the photovoltaic performance of solar devices. The cell fabricated from the blend solution at 65 °C exhibited enhanced power conversion efficiencies (PCE) of 5.11% with a J sc of 10.99 mA/cm -2 compared with the one at 50 °C, which had a PCE of 4.69% with a J sc of 10.10 mA/cm -2 . This enhancement is due to the dissolution of PDTBSeVTT-2TF clusters into single molecules and small aggregates, improving the miscibility between the polymer and PC 71 BM and thus increasing the donor/acceptor interface., Competing Interests: The authors declare no conflict of interest.

A UV-curable, flame-retardant monomer, DAPP (bis[di-acryloyloxyethyl]- p - tert -butyl-phenyl-phosphate), was synthesized based on BPDCP (4- tert -butylphenyl-dichloro phosphate) and HEA (2-hydroxy ethyl acrylate). DAPP was blended with regular bisphenol A epoxy acrylate (BAEA) in various ratios to yield various phosphorus contents. The TGA-IR (thermogravimetric analyzer interface with an infrared spectrometer) results demonstrate that compounding 30 mol % DAPP with BAEA significantly reduced the amount of released CO gas. In contrast, the peak intensity of CO₂ is independent of phosphorus content. The limiting oxygen index (LOI), reaching the saturated value of 26, and the heat release rate (HRR) measured using a cone-calorimeter, 156.43 KW/m², confirm the saturation point when 30 mol % DAPP was compounded into BAEA. A study of the kinetics of pyrolysis reveals that E a decreases as the phosphorus content increases. Both the TGA-IR and pyrolysis results reveal that the phosphorus compound DAPP is easily decomposed during the initial stage of burning to form an insulating layer, which inhibits further burning of the resin and the consequent release of other flammable gases.

Copolymerization of N -isopropylacrylamide (NIPAM), itaconamic acid (IAM; 4-amino-2-methylene-4-oxobutanoic acid) and β-cyclodextrin was investigated in this study. β-cyclodextrin was at first modified by reacting with allyl glycidyl ether to substitute its OH end groups with moieties containing double bonds to facilitate the subsequent radical copolymerization with NIPAM and IAM. It was reported that poly(NIPAM-IAM) can respond to the change of temperature as well as pH value. In this study, the structure of β-cyclodextrin was introduced to poly(NIPAM-IAM) copolymers because of its cavity structure capable of encapsulating a variety of drug molecules. The tri-component copolymers, poly(CD-NIPAM-IAM), were synthesized with different monomeric ratios of NIPAM/IAM/β-CD and the hydrogels of the tri-component copolymers were also synthesized by additionally adding N , N '-methylenebisacrylamide as a cross-linking agent. The results show that the lower critical solution temperature (LCST) of the copolymer (or hydrogel) increases as the molar fraction of IAM increases. The transmission electron microscopic (TEM) images of linear copolymers (no cross-linking) show that molecules undergo self-assembly to have a distinct core-shell structure, compared to poly(CD-NIPAM) which contains no IAM. On the other hand, the scanning electron microscopic (SEM) images of hydrogels show that the pores gradually become sheet-like structures as the molar fraction of IAM increases to enhance the water absorption capacity. In order to exhibit the thermal and pH sensitivities of poly(CD-NIPAM-IAM) as the drug carrier, the drug release of the newly synthesized hydrogels at 37 °C and different pH values, pH = 2 and pH = 7.4, was investigated using atorvastatin which was used primarily as a lipid-lowering drug. The drug release experimental result shows that poly(CD-NIPAM-IAM) as a drug carrier was pH-sensitive and has the largest release rate at pH = 7.4 at 37 °C, indicating it is useful to release drugs in a neutral or alkaline (intestinal) environment.

A series of novel p-type conjugated copolymers, PTTVBDT, PTTVBDT-TPD, and PTTVBDT-DPP, cooperating benzo[1,2-b:4,5-b']dithiophene (BDT) and terthiophene-vinylene (TTV) units with/without thieno[3,4- c ]pyrrole-4,6-dione (TPD) or pyrrolo[3,4- c ]pyrrole-1,4-dione (DPP) via Stille polymerization were synthesized and characterized. Copolymer PTTVBDT shows a low-lying HOMO energy level and ordered molecular-packing behavior. Furthermore, two terpolymers, PTTVBDT-TPD and PTTVBDT-DPP, display stronger absorption ability, alower-lying HOMO energy level, and preferred molecular orientation, due to the replacement TTV-monomer units with electron-deficient groups. Furthermore, bulk-heterojunction organic solar cells were fabricated using blends of the PTTVBDT-TPD, and PC 61 BM gave the best power conversion efficiency of 5.01% under the illumination of AM 1.5G, 100 mW·cm -2 ; the short circuit current ( J sc ) was 11.65 mA·cm -2 which displayed a 43.8% improvement in comparison with the PTTVBDT/PC 61 BM device. These results demonstrate a valid strategy combining the two-dimensional molecular structure with random copolymerization strikes promising conjugated polymers to achieve highly efficient organic photovoltaics.

In this study, chitosan (CS) grafted by glycidyltrimethylammonium chloride (GTMAC) to form GTMAC-CS was synthesized, chemically identified, and rheologically characterized. The Maxwell Model can be applied to closely simulate the dynamic rheological performance of the chitosan and the GTMAC-CS solutions, revealing a single relaxation time pertains to both systems. The crossover point of G' and G" shifted toward lower frequencies as the CS concentration increased but remained almost constant frequencies as the GTMAC-CS concentration increased, indicating the solubility of GTMAC-CS in water is good enough to diminish influence from the interaction among polymer chains so as to ensure the relaxation time is independent of the concentration. A frequency-concentration superposition master curve of the CS and GTMAC-CS solutions was subsequently proposed and well fitted with the experimental results. Finally, the sol-gel transition of CS is 8.5 weight % (wt %), while that of GTMAC-CS is 20 wt %, reconfirming the excellent water solubility of the latter.