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Studies on modeling and optimization of alkali treatment, investigation of experimental uncertainty and sensitivity analysis of alkali treatment factors of natural fibers are important to effective natural fiber reinforced polymer composite development. In this contribution, response surface methodology (RSM) was employed to investigate and optimize the effect of varied treatment factors (sodium hydroxide concentration (NaOH) and soaking time (ST)) of the alkali treatment of Ampelocissus cavicaulis natural fiber (ACNF) on the tensile strength (TS) of alkali treated ACNF reinforced polyester composite. RSM and multi gene genetic programming (MGGP) were comparatively employed to model the alkali treatment. The best model was applied in Oracle Crystal Ball (OCB) to investigate the uncertainty of the treatment results and sensitivity of the treatment factors. Results showed that increased NaOH and ST increased the TS of the alkali treated ACNF reinforced polyester composite up to 28.3500 MPa before TS decreased. The coefficient of determination (R2) and root mean square error (RMSE) of RSM model were 0.8920 and 0.6528 while that of MGGP were 0.9144 and 0.5812. The optimum alkali treatment established by RSM was 6.23% of NaOH at 41.99 h of ST to give a TS of 28.1800 MPa with a desirability of 0.9700. The TS of the validated optimum alkali treatment condition was 28.2200 MPa. The certainty of the experimental results was 71.2580%. TS was 13.8000% sensitive to NaOH and 86.2000% sensitive to ST. This work is useful for effective polymer composite materials production to reduce the enormous material and energy losses that usually accompany the process.

Tribo-electric nanogenerator proved a better alternative energy resource for many electronic accessories because of its flexible nature and optimized device properties. It opens up the use of polymer materials (PMs) for harvesting mechanical energy. The disadvantage of the Tribo-Electric Nano Generator (TENG) is likely lower durability, limited short circuit output current, structural changes, post-stress conditions, etc. The purpose of this review article is more focused on systematic and detailed descriptions of TENGs. It gives an overview of tribo-electric polymer-based material formation and triboelectricity generation, structural modes of tribo-electric polymer-based nanogenerators, and its comparisons, measurement, and quantification of tribo-electric polymer-based nanogenerators based on structural and load conditions. Also, this article focused on TNEG efficiency enhancement techniques using various charge control circuit techniques. Possible applications of TNEG for various self-powered devices such as sensor, actuators and bio-harvesting utilities are discussed in detail.

With the advance of nanotechnology in the insulation materials applications the polymers underwent structural changes, seen as individual and multiple nanoparticles techniques, moreover, frequency response analysis (FRA) provides an important prospective design for multiple nanocomposites applications. In this paper, the experimental work has been done for fabrication new polyvinyl chloride nanocomposites that is using individual and multiple nanoparticles to get low dielectric loss under thermal conditions. SEM images have detected the penetration of nano additives inside polyvinyl chloride materials that are obvious the patterns of utilizing individual and multiple nanoparticles. The series of experiments have performed on multi-nanocomposites of polyvinyl chloride samples in reference to additive free multiple nanoparticles (ZnO, Clay, Al2O3, and Fumed Silica) for controlling on dielectric losses with variant thermal conditions. Also, this paper has been discussed the electric field distribution inside dielectric nanocomposites and multiple nanocomposites for three-core belted power cables based on charge simulation method (CSM). Finally, it has been defined the features layout of using multi-nanoparticles that are enhancing multi-disciplinary properties of polyvinyl chloride as power cables insulation.

Sildenafil citrate (SC) has proved to be an effective and inexpensive drug for the treatment of pulmonary arterial hypertension (PAH). This study aims to synthesize electrospun, submicron fiber scaffolds of poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP) loaded with SC for fast drug dissolution and its potential use in the treatment of PAH. These fiber scaffolds were prepared through the electrospinning technique. The chemical composition of the nanofibers was analyzed by Fourier transform infrared spectroscopy. Thermal stability was studied by thermogravimetric analysis and polymeric transitions by differential scattering calorimetry. Surface analysis of the nanofibers was studied by field emission scanning electron microscopy. The wetting and dissolution time of the scaffolds and drug release rate were studied as well. The drug-loaded PVP fibers showed better quality regarding size and homogeneity compared to drug-loaded PVA fibers. These fibers encapsulated approximately 2.5 mg/cm2 of the drug and achieved immediate controlled released rate, which is encouraging for further studies leading to an alternative treatment of PAH in children.

Antibacterial materials have found widespread interest in different fields nowadays. In this study, curcumin (Cur) was incorporated into the polyvinyl butyral (PVB) matrix by dissolving in ethanol for improving the functional properties of a pure PVB film. We found that Cur was uniformly dispersed in the PVB matrix, which showed good compatibility. Moreover, the incorporation of Cur could also improve thermal stability, hydrophilicity, and mechanical property. The UV-vis spectra of the PVB–Cur film demonstrated that the film could block ultraviolet radiation. Subsequently, the antibacterial activity of the PVB–Cur film was measured by the colony-counting method against S. aureus and E. coli. The results showed that the PVB–Cur film exhibited good antibacterial activity. Therefore, the PVB–Cur film was considered as a promising material for food and medical packaging applications.

The solubility and diffusion coefficient of supercritical CO2 in polystyrene (PS) dynamic melt were studied by using a new constant pressure experimental device. By comparing the experimental results with those of other researchers, the validity of the experimental device and the reliability of the calculated results are verified. The solubility and diffusion coefficient of supercritical CO2 in polystyrene dynamic melts at different temperatures and pressures were obtained. The numerical calculation method, dissolution process, and experimental results are analyzed and compared with that of the static melt. Finally, the effects of stirring speed, pressure, and temperature fluctuation on the solubility and diffusion coefficient are also analyzed.

Epoxy resin is widely used in metal surface protection, because of corrosion resistance and adhesion. However, it’s water solubility, oxygen, and water impermeability are not enough. In this paper, linoleic acid (LOFA) and epoxy resin (E20) were used to synthesize epoxy ester (EL) and grafted with phosphonate esterified acrylic resin (AR-P) to prepare acrylic grafted epoxy ester (EL@AR-P). After modification, water solubility and film-forming property were improved, and the oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) decreased. At the addition of PM-2 at 2%, the OTR, WVTR, and water-uptake rate decreased by 12.9%, 25.0%, and 12.1%, respectively. Subsequently, the modified material was subjected to electrochemical impedance spectroscopy. The low-frequency impedance of EL@AR-P2 is three times higher than EL@AR-P0. After 16 days of immersion, the low-frequency impedance of EL@AR-P2 is 20 times higher than EL@AR-P. Energy dispersive spectrometer and X-ray photoelectron spectroscopy results showed that the P elements were concentrated on the substrate surface and found the presence of P–O–Fe bonds, demonstrating that the phosphonate groups were migrated to the substrate surface to form a chelate layer with the substrate and enhancing the coating adhesion and corrosion resistance. This paper modifies the molecular structure of epoxy resin, which is expected to be an excellent material for anti-corrosion coatings.

Microwave-assisted synthesis of the lipase-catalyzed ring opening polymerization of ε-caprolactone (ε-CL) and ω-pentadecanolactone (ω-PDL) monomers was studied. A series of P(CL-co-PDL), with different molar feed ratios, including (ε-CL/ω-PDL) 100/0, 75/25, 50/50, 25/75, and 0/100, were synthesized. The resulting polyesters were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The microwave-assisted polymerization of the monomers reached high conversions (91–95%) within 60 min. FTIR spectra showed the typical absorption bands of these polyesters. A very intense band in the carbonyl region, which was shifted from 1,720 cm−1 for PCL to 1,732 cm−1 for PPDL homopolymer, as well as peaks owing to methylene groups in the 2,990–2,850 cm−1 range. DSC results revealed that all polyester samples were semi-crystalline. Interestingly, the copolymers exhibited only one melting peak (T m), and their T m values linearly increased from 57°C to 95°C as PPDL concentration was increased. Thermal stability of polyesters also depended on PDL content; an increase in PDL concentration increases polymer degradation temperature (T d).

Modern microelectronics devices urgently request low dielectric constant materials with commendable mechanical properties. Novel fluorinated poly(aryl ether)s (FPPEs) were prepared by traditional polycondensation of 4-(4-Hydroxylphenyl)(2H)-phthalazin-1-one (DHPZ), Bisphenol AF (BAF) and Decafluorobiphenyl (DFB) to study bulky phthalazinone effects on mechanical and dielectric behavior of polymers. After the introduction of phthalazinone moieties, FPPEs showed excellent solubility to readily solve in many organic solvents like NMP, DMAc, CHCl3, and THF. Simultaneously, they exhibited relatively high glass transition temperatures (Tgs) from 180 °C to 294 °C, increasing with the content of phthalazinone groups. The FPPEs still possessed excellent thermal stability with decomposition temperature up to 514 °C and char yield at 800 °C as high as 56% under nitrogen atmosphere. FPPE films showed good mechanical strength with tensile stress higher than 68 MPa and modulus surpassing 10.8 MPa, also increasing with phthalazinone concentration. The dielectric property of FPPEs was investigated with impedance analyzer. FPPE8020 and FPPE 6040 showed dielectric constant from 3.10 to 3.30 and dielectric loss of 0.005–0.008 under a large frequency range of 0.02–60 GHz. The phthalazinone moieties mainly contributed to the decrease of dielectric constant. The results evidently suggest FPPEs as commendable candidate for those high-tech electronic applications.

Various phthalonitrile-based resins were prepared and their copper clad laminates were fabricated in this work. The curing behaviors and mechanisms were investigated by Dynamic rheological analysis (DRA) and in-situ FTIR. Results indicated that all phthalonitrile-based resins possessed wide process temperature windows and exhibit good processability. However, phthalonitrile-based resins resulted to various final crosslinking network in the presence of various catalyst/curing agents. Phthalonitrile-based copper clad laminates (CCL) were fabricated with hot-press mold technology. Mechanical properties of the CCL including flexural strength/modulus and peel strength were discussed, accompanied by the investigation of fractural surface of the laminates. Glass transition temperatures of the laminates were studied by both Differential scanning calorimetric (DSC) and Dynamic mechanical analysis (DMA). Then, fractural surface of fiber-reinforced composite laminates was investigated by Scanning electron microscope (SEM) and Micro slicing image (MSI). Results confirmed the satisfactory interfacial adhesion between resin matrices and fibers, which resulted to excellent mechanical properties of composite laminates. Then, dielectric properties of various composite laminates were investigated to evaluate their applications in the field of PCB substrates. Moreover, final dielectric properties of various phthalonitrile-based composites were discussed based on the transformation of molecular structures according to the polymerization mechanisms.

With the rise of the fifth-generation (5G) mobile communication, electromagnetic interference (EMI) and radiation become progressively serious toward electronic devices and human health, resulting in an increasing demand for EMI shielding materials. Polymer-based EMI shielding materials have drawn considerable attention in relevant industries and academia owing to their low density, easy processing, and superior flexibility. In this review, we systematically discuss the development of polymer-based shielding materials fabricated by using polymers as matrices and precursors. The architecture design of polymer composites is emphasized including homogenous structure, porous structure, laminated structure, and segregated structure. Specific attention is also given to the polymer derivatives from synthetic and natural polymers. Finally, we summarize the recent advancements and our guidelines for the development of polymer-based EMI shielding materials in the 5G era.

High-performance polymer materials with low dielectric constant and low dielectric loss have been widely used in high-speed communication network. This review briefly introduces several common polymer materials, including polyimides, poly (benzoxazole)s, poly (aryl ether)s, poly (tetrafluoroethylene), and various porous polymers. Moreover, the preparation technology, various properties and applications of common low-dielectric polymers are discussed. Based on the desired properties and requirements for applications as low dielectric materials, the possibility of further development of porous polymer materials is discussed.

A new type of phthalonitrile-etherified resole resin (PNR) was synthesized from resole resin and 4-nitrophthalonitrile. The differential scanning calorimetry results showed that the curing temperature of PNR is lower than that of phthalonitrile resin. Excellent thermal stability and bonding properties were obtained after curing at 220°C. TGA showed that in air, the temperature of 5% weight loss (T 5%) of the cured PNR was 446°C, approximately 41°C higher than that of resole resin (RS), and the char yield at 800°C increased from 4% for RS to 33% for PNR. The shear strengths of PNR at room temperature and high temperature were increased by 8% and 133%, respectively, over those of RS, and after aging at 350°C for 2 h, these values were increased by 262% and 198%, respectively, over those of RS. Its excellent curing behavior, heat resistance and high bonding strength show that PNR can be used as a high temperature-resistant adhesive.

A research is reported on the nanomechanics and tribology of the Arboblend V2 Nature biopolymer (a 100% bio-based material, biodegradable, or resistant depending of application), being a mixture of different biopolymers such as lignin, polylactic acid, cellulose, biopolyamides, and other natural additives. The specimens were made by an industrial-scale injection molding machine. The nanoindentation characterization have unveiled that an increase in processing temperature from 160°C to 170°C produces a rise in hardness and elastic modulus of ∼20%. Tribological characterization against a bearing-steel counterface has shown that for both processing temperatures, the increase of the applied load or the increase of sliding speed will produce an increase of the friction coefficient (µ) and wear. At an applied load of 1 N (contact pressure of 104 MPa) and tracks in a direction perpendicular to the surface textured lines, the lowest µ ∼ 0.148 are for samples made T = 170°C, while for tracks parallel to the textured lines, the lowest µ ∼ 0.059 is obtained for samples made at T = 160°C. Experiments made at different ambient humidity have established that friction coefficient is higher at 0% RH or at 75% RH than at 33% RH. Our results show that the biopolymers Arboblend V2 Nature is a candidate to substitute some popular fossil-based thermoplastics in numerous tribological industrial applications.

Sulfopropylated polysilsesquioxane and –COOH containing fluorinated sulfonated poly(arylene ether sulfone) composite membranes (SPAES-SS-X) have been prepared via an in situ sol–gel reaction through the solution casting technique. The composite membranes showed excellent thermal and chemical stability, compared to the pristine SPAES membrane. The uniform dispersion of the sulfonated SiOPS nanoparticles on the polymer matrix was observed from the scanning electron microscope images. Atomic force microscopy and transmission electron microscopy images indicated significantly better phase-separated morphology and connectivity of the ionic domains of the composite membranes than the pristine SPAES membrane. The composite membranes showed considerable improvement in proton conductivity and oxidative stability than the pristine copolymer membrane under similar test conditions.

Poly(l-lactide)-b-polyethylene glycol-b-poly(l-lactide) (PLLA-PEG-PLLA) is found to be more flexible than PLLA due to the flexibility of PEG middle blocks. Melt flow and mechanical properties of PLLA-PEG-PLLA were improved through post melt blending with a chain extender (CE). In this work, in situ chain-extended PLLA-PEG-PLLAs were synthesized by ring-opening polymerization in the presence of Joncryl® CE. The influence of CE content (1.0, 2.0, and 4.0 phr) on the gel content, melt flow index (MFI), thermal properties, and mechanical properties of the obtained in situ chain-extended PLLA-PEG-PLLAs was investigated. The gel content of in situ chain-extended PLLA-PEG-PLLA increased while the MFI and degree of crystallinity significantly decreased with increasing CE content. The in situ chain-extended PLLA-PEG-PLLA with 1.0 phr CE showed the best tensile properties. The extensibility of in situ chain-extended PLLA-PEG-PLLA films decreased when the CE contents were higher than 1.0 phr. These in situ chain-extended PLLA-PEG-PLLA films can be used as highly flexible bioplastics.

The work was aimed at the investigation of influence of peroxide curing system on cross-linking and properties of rubber compounds based on SBR. First, the temperature of vulcanization and the amount of dicumyl peroxide on curing process and physical-mechanical properties were investigated. Then, co-agents Type I and Type II were added to the rubber formulations cured with peroxide. The results revealed that the increase in temperature leads to the acceleration of curing process while both, curing kinetics and physical-mechanical properties were influenced by the amount of peroxide. The application of Type I co-agents resulted in the acceleration of curing process and increase in cross-link density of vulcanizates, which was reflected in the increase of hardness and decrease of elongation at break. The influence of Type II co-agents on curing kinetics was negligible, while most of them caused the reduction in cross-linking degree of vulcanizates. Type I co-agents contributed to the improvement of tensile strength of vulcanizates, while the influence of Type II co-agents on tensile strength was of minor importance.

Aqueous Polyurethane Dispersions (APUD) have been at the epicenter of the coating industry & research, devising greener solutions to modern coating problems. The formulation of APUDs involves many components namely, polyols, isocyanates, chain extenders, and ionic centers which enable the Polyurethane to be dispersed in water. This reduces the dependence on solvent-based coatings, providing a better and eco-friendly replacement for existing systems. Advantages like ambient temperature curing and excellent adhesion further reinforce the case for APUD. This review encompasses the synergistic effect of said components while painting a vivid picture of how they would affect the final properties of the coating.

The melt drawability including melt strength (MS) and stretching ratio (V) of the neat low-density polyethylene (LDPE) and the LDPE composites loaded with a nanometer zinc oxide (nano-ZnO) were measured using a melt spinning method in capillary extruding temperature varied from 160 to 200 °C and within capillary flow rate range from 9 to 36 mm/s. It was found that the stretching ratio of the neat LDPE and the LDPE/nano-ZnO composites reduced with an increase of capillary flow rate while the V added with in a rise of capillary temperature. The melt strength of the neat LDPE and the LDPE/nano-ZnO composites enlarged with raising capillary flow speed; the MS reduced with an addition of capillary temperature. In addition, the dependence of the MS of the composites on the capillary temperature approximately accorded the Arrhenius expression.

High internal phase emulsions (HIPEs) are among complex biphasic fluids that expand on the traditional emulsion compositions, for instance, for the preparation of macroporous polymers by emulsion templating. The use of deep eutectic solvents (DESs) as the nonaqueous internal phase of HIPEs allows expanding the conditions at which polymerizations are typically carried out in aqueous HIPEs. Herein, the properties of polystyrene macroporous polymers were studied by polymerizing DES-in-oil HIPEs using choline chloride-based DESs as the internal phase. The effect of DESs’ composition – with amide, alcohol, and carboxylic acid as hydrogen bond donors – and the homogenization method used for the HIPE preparation – vortexing versus high-speed homogenizer – was studied. The stability and droplet size of HIPE precursor, as well as the macroporous structure and the mechanical properties of the synthesized polyHIPEs, are discussed.

The intelligent poly N,N-dimethylacrylamide hydrogel material system with high mechanical strength and the 3D printable property was prepared via in situ free radical polymerization under vacuum successfully. With the increase in nanofibrillated cellulose (NFC) content, stress and strain of hydrogels increased gradually. As the effective reinforcement, NFC enhanced the crosslinking density, which realized the controllable regulation of rheology behaviors including viscosity, storage modulus, and loss modulus of hydrogels. Combined with the swelling rate and the existence of the gel–sol transition point, a hydrogel with 10 mg/mL NFC was treated as the 3D printing ink of hydrogel actuators. Variation of printing parameters significantly affected self-driven deformations. The hydrogel actuators with 90°/0° and 45°/135° configurations owned bending and spiral deformations, respectively. Actuators with a larger length–width ratio owned a lower pitch value. The precise anisotropic swelling property of the printed bilayer structure was the self-driven deformation mechanism of hydrogel actuators, which provided material candidates for the preparation of soft robots and actuators.

The demand of high-performance filter media for the face masks is urgent nowadays due to the severe air pollution. Herein, a highly breathable and thermal comfort membrane that combines the asymmetrically superwettable skin layer with the nanofibrous membrane has been fabricated via successive electrospinning and electrospraying technologies. Thanks to high porosity, interconnected pore structure, and across-thickness wettability gradient, the composite membrane with a low basis weight of 3.0 g m−2 exhibits a good air permeability of 278 mm s−1, a comparable water vapor permeability difference of 3.61 kg m−2 d−1, a high filtration efficiency of 99.3%, a low pressure drop of 64 Pa, and a favorable quality factor of 0.1089 Pa−1, which are better than those of the commercial polypropylene. Moreover, the multilayer-structured membrane displays a modest infrared transmittance of 92.1% that can keep the human face cool and comfort. This composite fibrous medium is expected to protect humans from PM2.5 and keep them comfortable even in a hygrothermal environment.

In this study, core–shell particles were prepared as a hybrid material, in which a thin polymer shell was formed on the surface of the SiO2 sphere particles. The core–shell structure was successfully achieved without adding a surfactant via simple free-radical polymerization (soap-free emulsion polymerization) for various monomers of styrene, methyl methacrylate (MMA), and their derivatives. MMA formed thin homogeneous shells of polymer (PMMA) less than 100 nm in thickness with complete surface coverage and a very smooth shell surface. The obtained shell morphology strongly depended on the monomers, which suggests different shell formation mechanisms with respect to the monomers. It was found that the cross-linking monomer 1,4-divinylbenzene tends to promote shell formation, and the cross-linking reaction may stabilize the core–shell structure throughout radical polymerization. It should also be noted that the present method produced a considerable amount of pure polymer besides the core–shell particles. The glass transition temperatures of the obtained polymer shells were higher than those of the corresponding bulk materials. This result suggests strong interactions at the core–shell interface.

All-organic high dielectric materials are highly required in the field of modern electronic industry and energy storage. In this work, all-organic polyimide/polysulfone composite films with different amounts of PSF (PI/PSF-X) were prepared by in situ polymerization followed by film casting and thermal treatment. The dielectric, mechanical and thermal properties of these PI/PSF-X composite films are characterized by dielectric measurement, tensile test, thermogravimetric analysis and dynamic mechanical analysis. The results suggest that the PI/PSF-X composite films have good dielectric properties, good mechanical properties and excellent thermal properties, which are suitable for applications in electronic devices in harsh environments, especially in high-temperature environments.

The influence of density of amino groups, nanoparticles dimension and pH on the interaction between end-functionalized polymers and nanoparticles was extensively investigated in this study. PS–NH2 and H2N–PS–NH2 were prepared using reversible addition–fragmentation chain transfer polymerization and atom transfer radical polymerization. Zero-dimensional carbon dots with sulfonate groups, one-dimensional cellulose nanocrystals with sulfate groups and two-dimensional graphene with sulfonate groups in the aqueous phase were added into the toluene phase containing the aminated PS. The results indicate that aminated PS exhibited the strongest interfacial activity after compounding with sulfonated nanoparticles at a pH of 3. PS ended with two amino groups performed better in reducing the water/toluene interfacial tension than PS ended with only one amino group. The dimension of sulfonated nanoparticles also contributed significantly to the reduction in the water/toluene interfacial tension. The minimal interfacial tension was 4.49 mN/m after compounding PS–NH2 with sulfonated zero-dimensional carbon dots.

Recently, there has been an increasing interest in the control of morphological transition of block copolymer aggregates. Here, we report how to control the morphological transition of methoxy polyethylene glycol–poly(d,l-lactic acid) (PDLLA–MPEG) by adding 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)] (DSPE–PEG). In the aggregates formed by dialyzing DSPE–PEG/PDLLA–MPEG mixed solutions against water, the two hydrophobic fatty acid tails of DSPE–PEG will preferentially anchor to the hydrophobic segment end of PDLLA–MPEG by interdigitating between these two tails and PDLLA segments. Consequently, DSPE–PEG and PDLLA–MPEG will form “ABA” temporary supra-amphiphiles in which A represents a poly(ethylene glycol) (PEG) chain segment and B is a mixed hydrophobic segment composed of PDLLA and DSPE segments; the repulsive force derived from the PEG segments of DSPE–PEG can affect the stability of “ABA” temporary supra-amphiphiles. Our results show that the dynamic subtle balance between the number of “ABA” temporary supra-amphiphiles formed and the strength of repulsive force between the PEG segments of DSPE–PEG drives the morphological structure of DSPE–PEG/PDLLA–MPEG aggregates to change from micelles to vesicles, then to semi-vesicles and finally to mixed micelles, with increasing DSPE–PEG additions.

A new piperonylic acid derivative (BPASD) was synthesized and evaluated as an organic nucleating agent for poly(l-lactic acid) (PLLA) via melt-crystallization; the other behaviors including cold-crystallization, melting process after crystallization, thermal stability in air atmosphere, and optical and mechanical properties of PLLA/BPASD samples were also investigated. The results of the melt-crystallization investigation showed that, in comparison to virgin PLLA, the BPASD could induce PLLA to crystallize in higher temperature region or at a faster cooling rate, suggesting that the BPASD as a heterogeneous nucleating agent could promote the crystallization of PLLA, but the melt-crystallization depended on the cooling rate, BPASD concentration, and the final melting temperature. With increasing of BPASD concentration, a shift to the lower temperature of cold-crystallization peak and decrease of crystallization enthalpy indicated that BPASD had an inhibition for the cold-crystallization of PLLA to some extent. The heating rate, crystallization temperature, the BPASD, and its concentration were critical factors to the melting process, and double-melting peaks appeared in heating were assigned to melting–recrystallization. Thermal decomposition behavior revealed that the addition of BPASD reduced the thermal stability of PLLA, but the interaction of PLLA and BPASD could prevent the decrease of the onset decomposition temperature. Further, the BPASD also decreased the light transmittance and elongation at the break of PLLA, but the tensile modulus and tensile strength of PLLA were enhanced.

Antibacterial epoxy resins (EP) have great potential in medical and electronic fields. During the process of extracting artemisinin from Artemisia annua, artemisia naphtha (AN) is generated as waste. The components of AN show antibacterial activity, and hence, it is introduced as a novel antibacterial agent in the epoxy matrix. In this study, the properties of epoxy resins with various AN loading were investigated. The results showed that AN/EP composites presented strong antibacterial activity against Escherichia coli and Staphylococcus aureus at the sterilization ratio of 100% against E. coli and 99.96% against S. aureus, respectively. Meanwhile, the thermal properties (curing temperature and glass transition temperature) of AN/EP composites remained well, and the mechanical property was even improved. Especially, the flexural strength of AN/EP composites could be reinforced by 62.9% when the content of AN was up to 5 wt%. For comparison, Artemisia annua powder (AAP), which was directly smashed from natural A. annua, was also mixed with epoxy resins as an antibacterial agent and showed excellent antibacterial property. Therefore, antibacterial epoxy composites containing A. annua waste as a natural resource with the enhanced mechanical property may have enormous potential in future biological and healthcare fields.

A novel full bio-based ketone-containing aliphatic polyester was prepared by enzyme-catalyzed polycondensation of diethyl γ-ketopimelate (DEK) with 1,6-hexanediol (HDO) using immobilized lipase B from Candida antarctica (CALB). The influences of polymerization conditions such as temperature, time, enzyme amount, and solvent amount on the molecular weight of poly(hexamethylene γ-ketopimelate) (PHK) were investigated. New fully bio-based poly(hexamethylene γ-ketopimelate-co-hexamethylene adipate) (poly(HK-co-HA)) copolymers with narrow polydispersity and well-defined composition were synthesized by copolymerization of DEK, HDO, and diethyl adipate. The structures of PHK and poly(HK-co-HA) copolymers were characterized by nuclear magnetic resonance, and their thermal characterization was examined by thermogravimetric analysis and differential scanning calorimetry. The degradation of PHK and poly(HK-co-HA) copolymers was studied. The post-polymerization modification of these polyketoesters via oxime click chemistry was further demonstrated.

A scaling relation of the electric conductivity behavior of high-density polyethylene (HDPE) composites loaded with carbon black (CB) and carbon fibers (CF) was studied. The results demonstrated, the curves of the scaled current density ( J s c ) versus the scaled electric field intensity ( E s c ) and the curves of a scaled conductivity ( σ s c ) versus J s c and E s c were linear in a bi-logarithmic coordinate system. There was a scaling relationship between the nonlinear electrical conductivity properties of the HDPE conductive composites; the HDPE/CB conductive composites satisfied an excessive degree relation, while the HDPE conductive composites reinforced with CF did not strictly satisfy a hyperscaling relation due to the CF weakening the nonlinear electric conductivity behavior of these composite. In addition, the introduction of the ethylene-vinyl acetate copolymer (EVA) into these composites was helpful to disperse the CB in the HDPE matrix, leading to presenting obviously linearity in a bi-logarithmic coordinate system.

Elastomeric nano-particles (ENPs) have been used widely and nano-scale effects have been found when used in polymer modification. For example, ENPs could increase toughness and heat resistance of plastics simultaneously when blending ENPs with plastics. Anomalies have also been found when ENPs were used in rubber modification, thermoplastic vulcanizates (TPVs) preparation and assisting dispersion of other nano-particles and ultra-fine additives in polymer matrix. The preparation, nano-scale effect and applications of the ENPs will be reviewed in this feature article. Keywords: Nano-scale effect, Polymer nano-composites, Elastomeric nano-particles, Plastic, Toughening

To meet the increasing requirements of membrane humidification in proton exchange membrane fuel cells (PEMFCs), a series of montmorillonite (MMT)/PEBAX® 1074 mixed matrix membranes (MMMs) were fabricated using the solvent casting method. Pristine MMT and poly(oxyalkylene)amine (APOP)-modified MMT were added as the filler. Using the XRD, FT-IR, SEM, and TEM, the morphology and chemical structure of MMT during modification were investigated. Using the tests of water vapor permeability, air permeability, water contact angle, and crystallinity, the effects of montmorillonite on membrane properties were investigated. The results showed that surface hydrophilicity and crystallinity of MMMs increased as the MMT content increases, which leads to higher vapor permeability and selectivity than the pure PEBAX® 1074 membrane. After modification, APOP-MMT/PEBAX® 1074 MMMs showed better performance in vapor permeability and vapor/air selectivity. The best selectivity was 1.7 × 105, which is three times higher than that of pure PEBAX® 1074 membrane.

Porous material (PM) shows good sound absorption performance, however, the sound absorbing property of PM with different parameters are greatly different. In order to match the most suitable absorbing materials with the most satisfactory sound-absorbing performance according to the noise spectrum in different practical applications, multi-population genetic algorithm is used in this paper to optimize the parameters of porous sound absorbing structures that are commonly used according to the actual demand of noise reduction and experimental verification. The results shows that the optimization results of multi-population genetic algorithm are obviously better than the standard genetic algorithm in terms of sound absorption performance and sound absorption bandwidth. The average acoustic absorption coefficient of PM can reach above 0.6 in the range of medium frequency, and over 0.8 in the range of high frequency through optimization design. At a mid-to-high frequency environment, the PM has a better sound absorption effect and a wider frequency band than that of micro-perforated plate. However, it has a poor sound absorption effect at low frequency. So it is necessary to select suitable sound absorption material according to the actual noise spectrum.

A strategy for the synthesis of well defined poly(ethylene glycol)-block-poly(methyl methacrylate) diblock copolymers containing trityl ether acid cleavable junctions is demonstrated. This approach is achieved by using a combination of poly(ethylene glycol) macroinitiator containing a trityl ether end group, which is susceptible to acid cleavage, and atom transfer radical polymerization technique. The trityl ether linkage between blocks can be readily cleaved in solution or in solid phase under very mild acid condition, which has been confirmed by 1H NMR. These diblock copolymers have been used to successfully fabricate nanoporous thin films by acid cleavage of trityl ether junction followed by complete removal of poly(ethylene glycol) block. The fabricated nanoporous thin films may have a wide range of application such as Recessed Nanodisk-array electrode (RNE) or as a template to fabricate nanoelectrode array for senor applications.

Chopped jute fiber (JF) surfaces were modified using alkaline, silane and eco-grade epoxy resin. Surface characteristics of jute fibers were confirmed by FTIR and EDX analyses. JF filled polyurethane elastomer (TPU) composites were prepared via extrusion process. The effect of surface modifications of JF on mechanical, thermo-mechanical, melt-flow, water uptake and morphological properties of TPU-based eco-composites were investigated by tensile and hardness tests, dynamic mechanical analysis (DMA), melt flow index (MFI) test, water absorption measurements and scanning electron microscopy (SEM) techniques, respectively. Mechanical test results showed that silane and epoxy treated JF additions led to increase in tensile strength, modulus and hardness of TPU. Glass transition temperature (Tg) of TPU rose up to higher values after JF inclusions regardless of treatment type. Si-JF filled TPU exhibited the lowest water absorption among composites. Surface treated JFs displayed homogeneous dispersion into TPU and their surface were covered by TPU according to SEM micro-photographs.

Polymer flooding technology has shown satisfactorily acceptable performance in improving oil recovery from unconsolidated sandstone reservoirs. The adsorption of the polymer in the pore leads to the increase of injection pressure and the decrease of suction index, which affects the effect of polymer flooding. In this article, the water and oil content of polymer blockages, which are taken from Bohai Oilfield, are measured by weighing method. In addition, the synchronous thermal analyzer and Fourier transform infrared spectroscopy (FTIR) are used to evaluate the composition and functional groups of the blockage, respectively. Then the core flooding experiments are also utilized to assess the effect of polymer plugs on reservoir properties and optimize the best degradant formulation. The results of this investigation show that the polymer adsorption in core after polymer flooding is 0.0068 g, which results in a permeability damage rate of 74.8%. The degradation ability of the agent consisting of 1% oxidizer SA-HB and 10% HCl is the best, the viscosity of the system decreases from 501.7 to 468.5 mPa‧s.

The performance of Polystyrene microporous foaming (PS-MCF) materials is influenced by their microstructures. Therefore, it is essential for industrializing them to investigate the relationship between their microstructure and material properties. In this study, the relationship between the microstructure, compressive property, and thermal conductivity of the PS-MCF materials was studied systematically. The results show that the ideal foaming pressure of PS-MCF materials, obtaining compression performance, is around 20 MPa. In addition, the increase of temperature causes the decrease of sample density. It effects that the compression modulus and strength increase with the decrease of foaming temperature. Because the expansion rate and cell diameter of the PS-MCF materials reduce the thickness of cell wall, they are also negatively correlated with their mechanical properties. Moreover, there is a negative linear correlation between the thermal conductivity and cell rate, whereas the cell diameter is positively correlated with the thermal conductivity.

In this study, a type of epoxy-terminated branched polymer (ETBP) was used as an interface compati- bilizer to modify the poly lactic acid (PLA)/poly(butylene adipate-co-butylene terephthalate) (PBAT) (70/30) blends. Upon addition of ETBP, the difference in glass transition temperature between PLA and PBAT became smaller. By adding 3.0 phr of ETBP, the elongation at break of the PLA/PBAT blends was found increased from 45.8% to 272.0%; the impact strength increased from 26.2 kJ·m−2 to 45.3 kJ·m−2. In SEM analysis, it was observed that the size of the dispersed PBAT particle decreased with the increasing of ETBP content. These results indicated that the compatibility between PLA and PBAT can be effectively enhanced by using ETBP as the modifier. The modification mechanism was discussed in detail. It proposes that both physical and chemical micro-crosslinking were formed, the latter of which was confirmed by gel content analysis.

A significantly growing interest is to design new biodegradable polymers in order to solve fossil resources and environmental pollution problems associated with conventional plastics. A kind of new biodegradable polymers, aliphatic–aromatic co-polyesters have been researched widely and developed rapidly in recent years, since that can combine excellent biodegradability provided from aliphatic polyesters and good properties from aromatic polyesters. Out of which, poly (butylene-adipate-co-terephthalate) (PBAT) shows the most importance. PBAT has been commercialized by polycondensation reaction of butanediol (BDO), adipic acid (AA) and terephthalic acid (PTA) using general polyester manufacturing technology. And it has been considered to have desirable properties and competitive costs to be applied in many fields. Therefore, this review aims to present an overview on the synthesis, properties and applications of PBAT. Keywords: Biodegradation, Polyester, PBAT, Synthesis, Property, Application

The synthesis and characterization of copolymers of n-Butyl Acrylate (BA) and Poly(ethylene glycol) dimethacrylate (PEGDMA) were realized by microemulsion. In this synthesis, the relation of PEGDMA 10, 20, 30, 40 and 50% wt with respect to BA was changed. The copolymers obtained were characterized by the determination of conversions (gravimetry), infrared spectroscopy: Fourier transform (FTIR), dynamic light scattering (DLS), thermogravimetry (TGA) and differential scanning calorimetry (DSC). The results confirmed the synthesis of BA-co – PEGDMA copolymers by the identification of characteristic FTIR bands and which determined the glass transition temperature of the copolymers. The conversions were found in the range of 85% to 90%. Within the stability of the produced latex, it was observed that at 10% and 30% wt. of PEGDMA the systems were stable, but when more PEGDMA was added up 40% to 50% wt., the system became unstable. The stability of produced latexes depends on the PEGDMA contents and this must be less than 30% wt.; meanwhile the PEGDMA content greater than 30% wt. leads to unstable latexes, forming clots. Copolymers showed single glass transition temperatures between −53.37°C and −16.58°C, depending on the composition of PEGDMA in the copolymers. Resulting in the different arrangements of units of PEGDMA along in the chain affected the thermal properties of the final copolymers.

The phase morphologies and phase transitions of dendrimer block copolymer thin films confined between two homogeneous, planar hard substrates had been investigated by a three-dimensional real space self-consistent field theory (SCFT). From the perspectives of property and strength of the preferential substrate, when the film system confined within neutral substrates, the thinner film was easier to take the undulated and perpendicular cylinder phases. For the attractive preference of the substrate on block segment A, the polymer films tended to take the surface-wetting structures that was composed by block segment A. On the contrary, for the repulsive preference of the substrate on block segment A, a phase transition of cylinder-lamellae could be observed increasing with the relative surface strength of the preferential substrate.

A novel amphoteric polyacrylamide (PDAA) was prepared by inverse emulsion polymerization. The influence of its cationic degree and molecular weight on retention property was discussed. Then, the chemical structure and micromorphology of the obtained PDAA were characterized by Fourier infrared spectrum (FTIR), NMR hydrogen spectrum (1H NMR), gel permeation chromatography (GPC), and scanning electron microscope (SEM). Finally, the synergistic retention effects of polydimethyldiallylammonium chloride (PDADMAC), cationic starch (CS), cationic guar gum (CHPG), cationic chitosan (CTS), and polyamine (PA) on the novel PDAA were investigated. The results showed that the optimum cationic degree and molecular weight of PDAA were 25% and 4 million, respectively. The chemical structure of PDAA was confirmed by FTIR, 1H NMR, and GPC. SEM showed that the particle size of PDAA was between 150 and 600 nm, and the particles were very stable because no broken particles were found. In addition, most of the five cationic polymers have good synergistic retention effect on PDAA, and the order of synergistic effect was PDAA/PDADMAC > PDAA/CTS > PDAA/CS > PDAA/CHPG > PDAA/PA.

In this study, a new damage mode for the explosive reactive armour (ERA) of a shaped charge jet was proposed. The response characteristics of polytetrafluoroethylene (PTFE) and polyamide (PA) polymer jet impact on the ERA were analysed. The expansion degree and the diameter of the PTFE jet are larger than those of the PA jet, but the compactness of the PTFE jet head is lower than that of the PA jet, resulting in different impact pressures of the different polymer expansive jets on the target. The PTFE jet achieved the penetration without initiation of the ERA at different standoffs, while the PA jet directly detonated the sandwich charge when impacting the ERA vertically and failed to penetrate the front plate when impacting the ERA at 68°. With the increase of standoff, the reaction degree of the PTFE jet to the ERA decreased gradually, and the aperture of the front plate did not change.

6,7-Bis(hexylthio)-2-[(2-hydroxyethyl)thio]-3-methylthio-tetrathiafulvalene (TTF-2) is coupled with thiophene-3-carboxylic acid and thiophene-3,4-dicarboxylic acid by Steglich esterification, respectively, to afford 2-((4′,5′-bis(hexylthio)-5-(methylthio)-[2,2′-bi(1,3-dithiolylidene)]-4-yl)thio)ethyl thiophene-3-carboxylate (TTF-Th) and bis(2-((4′,5′-bis(hexylthio)-5-(methylthio)-[2,2′-bi(1,3-dithiolylidene)]-4-yl)thio)ethyl)thiophene-3,4-di-carboxylate (DTTF-Th). Their structures were characterized by ESI-MS, 1H NMR, and elemental analysis. Electropolymerization of TTF-Th and DTTF-Th was conducted with 0.1 M n-Bu4NPF6. The results indicated that both assemblies could rapidly form polymers via electrochemical deposition. In addition, their electrochromic performances illustrated that the color of P(TTF-Th) could switch from orange-yellow to dark blue, while P(DTTF-Th) changed its color from orange in the neutral state to dark blue in the oxidation state. Moreover, the electrochromic performances of P(DTTF-Th) were better than P(TTF-Th) due to the introduction of one extra TTF unit.

A new kind of coating consisting of zinc oxide (ZnO)/tetracalcium phosphate (TTCP)/gelatin (Gel) on the PET woven nets is prepared chemically by the method of atomic layer deposition (ALD) and hydrothermal method. The prepared materials are confirmed by XRD and SEM. XRD results show that ZnO and TTCP are well coated on the surface of PET woven nets and ALD-assisted ZnO leads to a surprising coating adhesion of about 8 MPa. Furthermore, SEM results indicate the diameter and morphology of ZnO, TTCP and Gel of PET woven nets. And the water contact angles of PET’s surface are decreased with ZnO, TTCP and Gel of PET woven nets. Moreover, the confocal imaging of NIH3T3 cells shows that the obtained product could promote the cells proliferation, which indicates that the good biocompatibility of the prepared PET/ZnO/TTCP/ Gel woven builds a foundation for their future application. The results aim to obtain an efficient method to modify PET for fabricating an ideal artificial implant meeting the clinical needs, and imply a positive effect in promoting the compatibility of PET for enhancing graft-bone healing after implantation.

This paper reviews the recent development of starch-based materials, including both fundamental and application researches. In order to overcome the weakness of pure starch-based materials, such as lower mechanical properties found in natural polymers and moisture sensitivity, various blends and composites have been developed in the last two decades. In practical, incorporation of any additives is sensitive in developing fully biodegradable starch-based materials. Furthermore, safety issues will be considered as priority regarding any additives for food packaging applications. Based on these concerns, various natural filler and edible reinforce agents, such as natural fibers, starch or cellulous crystals, and laver, have been used in starch-based materials. So-called self-reinforced techniques, reinforcing starch matrix by modified starch particles, have also been used in developing starch-based composites. During developing starch-based foams the unique function of water, acts as both plasticizer and blow agent for starch-based foam, has been systematically studied. So far, various conventional processing techniques such as extrusion, injection, compression molding, casting and foaming, as well as some new techniques such as reactive extrusion, have been adapted for processing starch-based polymeric materials. Various starch-based products have been developed and commercialized. Keywords: Starch, Biodegradable, Edible, Processing, Phase transitions, Foam

Two benzimidazole-based conjugated polyelectrolytes (+)-PPBIPV and (-)-PPBIPV which have opposite charges on their side chains were synthesized via Heck coupling reaction and characterized by 1H-NMR, UV-vis and PL spectroscopy. These two polyelectrolytes are both consisted of benzimidazole derivatives and phenylenevinylene units. The absorption and emission spectra reveal that the polymers both have solvent-dependency and concentration-dependency, and they exhibit aggregation effect in aqueous solution. In the respect of ion detection, the aqueous solution of (+)-PPBIPV has excellent selectivity and sensitivity for Fe3+. Moreover, Pd2+ can almost completely quench the fluorescence of (+)-PPBIPV in methanol solution, and its quenching constant K SV is 5.93×104 M-1. For (-)-PPBIPV, Sn2+ can double the fluorescence intensity of its aqueous solution, while (-)-PPBIPV has good identification for Fe3+ in methanol with a K SV = 3.44×105 M-1. Hence, two polyelectrolytes have considerable potential to become effective fluorescent sensing materials for some specific metal ions. All of the stoichiometric relationships between metal ions and conjugated polyelectrolytes were calculated using Benesi-Hildebrand equation.

Flexible energy devices with high energy density and long cycle life are considered to be promising applications in portable electronics. In this study, silicon/carbon nanofiber (Si@CNF) core–shell electrode has been prepared by the coaxial electrospinning method. The precursors of polyimide (PI) were for the first time used to form the core–shell structure of Si@CNF, which depicts outstanding flexibility and mechanical strength. The effect of doping concentrations of silicon (Si) nanoparticles embedded in the fiber is investigated as a binder-free anode for lithium-ion batteries. A 15 wt% doped composite electrode demonstrates superior performance, with an initial reversible capacity of 621 mA h g−1 at the current density of 100 mA g−1 and a high capacity retention up to 200 cycles. The excellent cycling performance is mainly due to the carbonized PI core–shell structure, which not only can compensate for the insulation property of Si but also has the ability to buffer the volume expansion during the repeated charge–discharge process.

Various aspects of electrospun fibers prepared from terpolymer of tetrafluoroethylene (TFE), hexafluoropropylene (HFP), and vinylidene fluoride (VDF) (THV)/acetone solutions at two applied voltages, THV/acetone solutions having Texas montmorillonite with two ratios, and THV/ethyl acetate solutions using two needle sizes are described. Fibers from THV/acetone and THV/ethyl acetate solutions showed shallow indentations and pores, respectively. The clay, functioning as electrospinning agent, did not influence the fiber morphology, but yielded narrower fiber diameter distribution and the thinnest fibers. Heterogeneous fiber diameter distribution and increase in the fiber diameters were observed by lowering the voltage for fibers of THV/acetone solutions. Fibers from THV/ethyl acetate solutions had the largest diameter and the broadest diameter distribution. Electrospun THV fibers having both hydrophobic characteristics with nearly 140° water contact angles and oleophilic properties with oil contact angles less than 45° might have applications in areas such as water/oil separation.

In order to promote the degradation of PLA in seawater, a series of seawater-degradable polyester blends PVA/PLA were prepared by blending biodegradable polylactic acid (PLA) with water-soluble modified polyvinyl alcohol (PVA) in this paper. ADR 4370S was introduced to bring a certain degree of improvement in compatibility of PVA/PLA blends. The results of degradation test in natural seawater for 180 days show that the weight loss of PVA/PLA blends in seawater is much higher compared with that of pure PLA. PVA can be used as an effective hydrolysis accelerator for PLA matrix, helping to significantly reduce the molecular weight of PLA. The channels caused by dissolution/swelling of PVA facilitate the entry of water and microorganisms into the materials to contact with PLA, thereby promoting the degradation process of PLA matrix itself. Thus, both dissolution/swelling of PVA and degradation of PLA occur in PVA/PLA blends, and the degree of rapid dissolution of PVA in the early stage determines the degree of degradation of PLA.