Journal of Polymer Research最新文献

Fusion deposition modeling (FDM) has developed remarkably over the last few decades as an innovative and versatile method of producing objects with complex design details. Polylactic acid (PLA), a bio-based polymer, is one of the most widely used thermoplastics in fabricating products with FDM due to its favorable mechanical properties, relatively low cost, and recyclability. However, most PLA studies in the literature have focused on evaluating its mechanical performance according to the 3D-printed parts to changing FDM parameters. This experimental study tries to elucidate high-speed mechanical performance of PLA samples at different waiting times depending on varying media such as dry, seawater, and distilled water. It aims to form a scientific bridge between the liquid absorption and high-speed deformation behavior of 3D-printed PLA. In addition, samples with three different layer heights were produced to investigate the combined effect of these media and process parameters on FDM parameters. Low-speed tensile tests, hardness tests, drop-weight impact tests, and damage inspections were carried out to analyze the samples thoroughly. These results indicated that there was an affirmative relation between the hardness values and layer height levels. The maximum drop weight force value was obtained in dry samples with 0.2 mm layer height. In addition, the maximum force was higher for samples stored in seawater than for other samples. The specific absorbed energy (SAE) value of the samples at 0.2 mm layer height after 15 days of waiting time was superior to that of the dry sample.

Herein, this study introduces a simple, effective, and potentially successful approach to the preparation of polymeric composite systems using a Polyvinyl alcohol (PVA)-Polyvinyl pyrrolidone (PVP)-Polyethylene glycol (PEG) (PVA-PVP-PEG), (8:1:1) as the host polymeric blend with the inclusion of Tb(NO₃)₃-salt filler. The diffraction of X-rays (XRD), infrared spectroscopic (FTIR), Ultraviolet–visible (UV–vis) spectroscopy, and Phy-X/PSD software were utilized to analyze the modified samples’ structures, identify their optical and radiation shielding properties. The XRD patterns show the presence of Tb(NO₃)₃ phases inside the composite matrix, where adding filler causes modifications in the polymeric network’s structure for filled composite samples. FTIR analysis showed that the Tb(NO₃)₃-salt interacted with the blend’s functional groups via H-bond formation. The UV–Vis spectra analysis showed all samples, especially those loaded with 8.0 wt.% Tb(NO₃)₃-salt has the highest values for absorbance, dielectric constant, refractive index, extinction coefficient, and optical and electrical conductivity. Tauc’s formula, the ASF model, and " ({varepsilon }_{i}-hv) plots were all applied to investigate optically the band gap in great detail. The values of ({text{E}}_{text{d}}) and ({text{E}}_{text{o}}) and ({text{n}}_{text{o}}) have been investigated using a single oscillator model where their values were controlled by Tb(NO₃)₃- salt content. Using calculated gap energy, various approaches were applied to obtain the conceptual significance of the linear refractive index ((n)). The nonlinear optical parameters ({upchi }^{(1)}), ({upchi }^{(3)}), and ({text{n}}_{2}) increased noticeably as the Tb(NO₃)₃-salt percentage is increased to 8.0 wt%. The suggested largely doped Tb(NO₃)₃-salt composites show great promise as a CUT-OFF laser filters and attenuators in addition to being used in laser power-limiting technology. Based on our results, the sample was 8.0 wt.% Tb(NO₃)₃-salt has better gamma-ray shielding properties than the others because it has the largest Tb(NO3)3-salt concentration. The study opens a new route to fabricate Tb(NO₃)₃/(PVA-PVP-PEG) polymeric composites with superior optical properties.

The current challenge with sulfonated aromatic polymer proton exchange membranes (PEMs) lies in their inability to enhance proton conductivity, mechanical strength and methanol resistance concurrently. To address this issue, a novel approach has been taken by synthesizing hydrophobic polysulfone grafted with hydrophilic sulfonated polyvinyl alcohol (PSU-g-SPVA) through Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization. This graft polymer is then utilized as a modified material for PEMs in direct methanol fuel cells (DMFCs). The morphology of phase separation within the Nafion matrix is significantly influenced by the proportion of PSU-g-SPVA. Notably, the Nafion/PSU-g-SPVA-40 modified demonstrates superior alcohol resistance, with a methanol permeability rate of 2.32 × 10⁻⁷ cm²/s. Furthermore, due to its outstanding proton conductivity, the proton selectivity of this modified membrane is an impressive 10.9 × 10⁴ S s/cm³, which significantly surpasses that of the standard Nafion membrane at 2.82 × 10⁴ S s/cm³. Grafting techniques of hydrophobic main chain and hydrophilic side chains open up a new method for the blending of polymers with huge polarity differences.

A series of novel network polymers P₁-P₆ and P_n-Zn_x:y based on metal–ligand coordination bonds with different strength were prepared by one pot method. The structures of the polymers were confirmed by NMR and FT-IR spectra. The amorphous structure of polymers was determined by X-ray diffraction analysis with only broad scattering peaks detected. The TGA and DSC showed that the increase of pyridyl group can dramatically improve the thermal stability of polymers, and T_g gradually decreases with the increase of pyridyl and pyridine groups. When the amount of Zn(II) increases, the thermal stability and the T_g gradually decreases. Optical microscope images indicated that the cross-linked network polymers P_n-Zn_1:2 all had obvious self-healing properties at room temperature, and the 50% cross-linked network P₃-Zn_1:2 and P₄-Zn_1:2 with less pyridine content have better self-healing performance. Further exploration of the self-healing properties of P₃-Zn_x:y by adjusting the molar ratio of dianhydride to Zn(II), P₃-Zn_1:4 has the best self-healing performance.

New natural cellulosic materials used to make high-performance bio-based composites are attracting a lot of attention due to their enhanced properties. This study aimed to investigate micro-sized cellulosic fillers produced from Mangifera indica (Mango) leaves (MIL) with respect to their morphological and physicochemical properties, thermal behaviour, crystallinity and other relevant parameters. Some of cellulose's notable properties are excellent mechanical capabilities, biocompatibility, low density, biodegradability and heat stability. An acid hydrolysis process was used to extract cellulose from dried MIL. Isolated microcrystalline cellulose's crystallinity index and crystalline size were measured using X-ray diffraction, with results of 58.6% and 20.28 nm, respectively. The extracted cellulose filler's morphology was investigated using FESEM and ImageJ. The FESEM image shows MCCs morphology, thick framework formation, cellular structure, microfibrils, surface roughness and bonding making it a promising candidate for high-strength applications due to its enhanced bonding surface and structural integrity. The average size of the microfillers was found to be 103.161 μm. The absence of lignin, hemicelluloses and other non-cellulosic impurities in the extracted cellulose fillers was verified by infrared analysis employing Fourier transforms (FTIR). The findings suggest that waste materials that are already present in nature can be transformed into useful components for polymeric composites that can withstand processing temperatures ranging from 180℃ to 200℃. Surface roughness indicates cellulose is smooth, appropriate and noticeable without cracks. Therefore, lot of possibilities for extrusion methods in incorporating these microparticles into polymer composites.

With the rapid economic development in recent years, there has been an increasing demand for durable and high-performance transportation road pavements. Polymer-modified asphalt has gained widespread acceptance due to its ability to enhance driving comfort and extend service life. Nevertheless, the longevity of asphalt pavements is often compromised by long-term traffic loads and harsh weather conditions, leading to cracking and degradation. To tackle this issue, dynamic chemistry introduces a promising solution for self-healing polymer-modified asphalt. By integrating dynamic bonds into the polymers structure, its network becomes adaptable to external triggers such as pressure, temperature, and pH, enabling material self-repair via dynamic healing mechanisms. This paper explores the synthesis methods and structural characteristics of dynamic self-healing polymers, their impact on the self-healing performance of modified asphalt and the classification of dynamic bonds. Additionally, the paper discusses methods for evaluating the self-healing performance and identifies future challenges and research directions for self-healing polymer-modified asphalt materials.

Building lighter but stronger has been a major industrial concern in recent decades. To achieve its goals, Altuglas International, a subsidiary of the Arkema group, has developed several types of nanostructured acrylic glass materials, that are lighter and more resistant than glass PMMA. Combining PMMA (polymethyl methacrylate) and a nanostructured elastomer, this material has perfect transparency and special mechanical properties. In addition to its automotive applications, its exceptional properties open up prospects in aeronautics and safety glazing. In the present study, different type of nanostructured PMMA, with different crosslink density has been studied and compared to standard PMMA, shock PMMA and polycarbonate (PC). Various mechanical tests, including, scratch-based friction tests (to assess the fracture and friction properties), indentation tests (to obtain elasto-plastic behavior and the creep response), fracture toughness assessment tests and dynamic mechanical analyses, have been performed. Furthermore, perforation tests, were carried out using pneumatic gas gun having different impact velocities varying from 8 to 161 m/s. The obtained results show the combined effect of both rubber bloc nanostructuration and crosslink density. It’s was observed that the addition of rubber at nanometer scale leads to improvement of mechanical properties such as toughness, friction and impact resistance. Moreover, when moderately increasing the crosslink density, several physical properties, including glass transition temperature, toughness, friction, hardness and ballistic limit were significantly improved.

Graphene oxide (GO) has a large specific surface area, and the filler agglomeration is serious when it is mechanically mixed in open mill or internal mixer, which is unable to give full play to the layer isolation effect of GO to better improve the oil and high temperature resistance of NBR composites. Therefore, in this paper, the change rate of mass and volume, oil resistance, high temperature resistance, tear properties, Payne effect and mechanical properties of NBR composites prepared by dry mixing process, ball-milling modified GO/silica/si69-dry mixing process, NBR flocculation process, and ball-milling modified GO/silica/si69-NBR co-flocculation process were investigated. The results showed that compared with the GO/silica/NBR composites prepared by dry mixing, the change rate of tensile product and abrasion volume of the GO/silica/NBR composites prepared by ball milling-co-flocculation process after high-temperature and oil bath were reduced by 35.28% and 16.69%, respectively, and the tear strength was increased by 57.28%, which possessed excellent oil resistance and high temperature resistance, providing new technical guidance for the application of GO in oil and high temperature resistant NBR systems.

The liquid argon (LAr) detector has garnered significant interest in recent experiments focusing on dark matter and neutrinoless double-beta decay searches. However, the wavelength shifting and light collection present persistent technical challenges for the liquid argon (LAr) detector. In this work, a novel plastic scintillator material was developed and optimized to enhance the light collection efficiency of LAr detectors. The plastic scintillator was prepared via thermal polymerization, utilizing styrene as the matrix doped with TPB (1,1,4,4-tetraphenyl-1,3-butadiene). A mass fraction of 1% of TPB-PS has been identified as the optimal concentration, emitting the strongest blue fluorescence with a quantum yield of 99.89%. The fluorescence emission spectrum of the new material peaks at 440 nm, which aligns with the best quantum efficiency of conventional photoelectron converter devices. The light yield of the 1% TPB-PS is 73.98% relative to the value of the standard sample EJ-200. Its decay time is 2.75 ns approximately. Mechanical tests present the developed TPB-PS material can be used as an active structure material for LAr detectors in next-generation experiments. Furthermore, the TPB-PS material can be prepared into wavelength-shifting (WLS) optical fiber, which can be coupled with silicon photomultipliers (SiPMs) to enhance the light collection efficiency of LAr detectors, improving background rejection and energy resolution.

Enzyme immobilization in the microfluidic chip channel to improve enzyme activity and stability has become a powerful strategy to enhance biocatalysis and biomass conversion. Here, a miniaturized glucose biosensor in which glucose oxidase (GOx) was efficiently immobilized in the PDMS chip microchannel by layer-by-layer self-assembly was developed and used successfully for amperometric determination of glucose. After the surface of PDMS microfluidic chip was treated with 365 nm ultraviolet light, the methacrylic acid monomer was grafted onto it using poly dimethyl diallyl ammonium chloride as linker, then GOx was electrostatically adsorbed on the inner wall of the PDMS chip microchannel to construct multilayer GOx. According to the results of confocal laser scanning microscopy, immobilized enzyme activity, and GOx loading, the maximum quantity of enzyme immobilized on 4 layers of GOx was observed within the PDMS microchannels. The amperometric response of glucose with the biosensor under the optimal conditions exhibited linear relationship in the range of 0.4 to 2.0 mM with correlation coefficient 0.9973, and the limit of detection was 84 μM. In addition, the microfluidic system greatly reduced the consumption of samples during tests and showed excellent accuracy, stability and reproducibility.