Journal of Polymer Research最新文献

High-density polyethylene (HDPE) nanocomposites with alpha alumina nanoparticles at various weight fractions (0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, and 3 wt%) were successfully synthesized using the hot press method. X-ray diffraction (XRD) results revealed that increasing the weight percentage of alumina had no significant effect on the initial semi-crystallinity. Atomic force microscopy (AFM) images revealed that achieving high surface homogeneity is possible at higher alumina contents. Positron annihilation lifetime spectroscopy (PALS) and low energy positron beam technique (LEPB) were used to investigate the size, concentration and shape of the free volume. The results from positron annihilation spectroscopes indicated that increasing the weight percentage of alumina reduces the size, shape, and homogeneity of free volume structure.

Herein, methyl acrylate functionalized hyper-crosslinked polymers (HSDMs) were synthesized using the suspension polymerization method and they were employed to adsorb aromatic small molecule compounds. Low-crosslinked precursor polymers were prepared using styrene (St) and divinylbenzene (DVB) as crosslinking agents and different ratios of methyl acrylate (MA, 20, 15, 10, 5%) as functional monomers. Subsequently, the Friedel–Crafts reaction was conducted at 313 K to yield products characterized by hyper-crosslinked interpenetrating polymer networks abundant in rigid methylene bridges. The resulting polymers were promising for the adsorption of aromatic small molecule compounds from aqueous solutions, and the maximum capacities (q_max) for aniline, phenol and salicylic acid arrived at 103.79, 98.75 and 229.98 mg/g at 288 K. The kinetic experiments demonstrated that adsorption aniline, phenol and SA reached the equilibrium within 60, 60 and 150 min, and the kinetic results were accurately described by the pseudo-second-order (PSO) rate model, exhibiting kinetic rates of 8.34 × 10^–4, 1.01 × 10^–3, and 5.00 × 10^–4 g/(mg·min), respectively. At room temperature, the dynamic adsorption capacity of HSDM-5 for aniline is 50.06 mg/g and the desorption efficiency is 90.74%. The adsorption mechanism discovered that hydrophobic interaction, π-π stacking, pore-filling and hydrogen bonding were important for the adsorption. 

Graphical Abstract

Polymer foam composites for sound absorption with eco-friendly attributes have gained significant attention in sustainable materials research. This study investigates the impact of ultraviolet (UV) irradiation on the morphological, mechanical, and acoustical properties of bio-epoxy (BE) and synthetic epoxy (SE) foam composites, incorporating wood flakes as fillers at varying loadings (0–20 wt%). BE, derived from waste cooking oil, demonstrated superior resilience to UV exposure compared to SE, maintaining better pore structure, mechanical stability, and sound absorption performance. The results show that after 6000 h of UV exposure, BE composites retained 12–18% higher sound absorption coefficient (α = 0.62–0.78) than SE composites (α = 0.50–0.66) at 3000 Hz after 6000 h of UV exposure, demonstrating superior UV resilience. At 6000 Hz, SE outperformed BE (α = 0.45 vs. 0.35) as a result of structural degradation in BE at higher frequencies, attributed to the natural stabilizing properties of bio-based additives. This study proves that BE foam composites offer improved durability and acoustic performance under prolonged UV exposure, positioning them as promising materials for sustainable acoustics applications.

The type of matrix resin determines the service performance of the semi-conductive shielding materials (SCSMs) and serves as the most critical component for achieving the functionality of the semi-conductive shielding layer in power cables. This work selects the typical matrix resins commonly used in SCSM of power cables, namely ethylene–vinyl acetate (EVA), ethylene-butyl acrylate (EBA), and ethylene-ethyl acrylate (EEA), emphatically analyzes the microstructure and performance characteristics of the matrix resins, and systematically explores the impact of matrix resin on the comprehensive performance of SCSM. The research findings indicate that, compared to EVA, both EBA and EEA exhibit higher molecular weights and crystallinity, as well as enhanced melting points and superior thermal stability. The EBA-based SCSM demonstrates optimal volume resistivity and surface smoothness. Comprehensive analysis suggests that EBA is the ideal matrix resin for SCSM in power cables. This research is expected to provide a theoretical basis for the selection of raw materials for SCSMs and the development of power cables. 

For advanced technical applications, environmentally-neutral basalt fiber reinforced epoxy (BF/Ep) composites hold promise as they combine the strength, durability, and environmental benefits of basalt fibers with the toughness and adaptability of epoxy. The mechanical characteristics and fractography of epoxy-based composites with and without plain weave basalt fiber mats treated with silane are investigated in this work. The composites were produced by hand-laying up and hot pressing. Untreated and silane-treated BF/Ep samples were subjected to mechanical tests, including microstructure, hardness, tensile, short beam, flexure, and impact, in compliance with ASTM guidelines. Mechanical property studies revealed that the silane-treated BF/Ep composites had a substantially higher mechanical strength than the untreated BF/Ep composites. Maximum tensile strength (276.8 ± 6.3 MPa), interlaminar shear strength (33 ± 2.0 MPa), flexural strength (289.2 ± 9.5 MPa), impact strength (170.4 ± 2.5 J), and Rockwell hardness (124 ± 2) were found for the silane-treated BF-Ep composite samples. In terms of microhardness, tensile strength, interlaminar shear strength, flexural strength, and impact strength, the epoxy composite treated with silane and containing 60% BF mats was the best. Thus, in addition to other functions provided by either BFs or the epoxy matrix, the addition of high mass fractions of BF mats to an epoxy matrix may be advantageous for applications needing superior mechanical properties. Moreover, fractographic analysis showed that the fiber/matrix adhesion was comparatively weaker, which made it a preferred location for crack nucleation. Additionally, there was proof that the silane-treated fiber had cracked arrest above 55 wt. %. 

CO₂ copolymer diol (PPCD) with superior transparency is an indispensable raw material for the polyurethane, especially for waterborne polyurethane coatings. However, commercial PPCD is generally opaque. In this work, A sustainable, colorless and transparent PPCD was prepared by using carbon dioxide (CO₂) and propylene oxide (PO) as raw materials. Research shows that the increase in CO₂ content (from 23.5 wt.% to 31.5 wt.%) will affect the transparency and thermal stability of PPCD and the transparency of PPCD with 29.1 wt.% CO₂ content is even higher than 90%, while the 5 wt.% mass loss temperature reaches 240.1 ℃. Furthermore, a series of waterborne polyurethane (WPU) was successfully synthesized by prepolymer method with PPCD as the soft segment. With the increase of CO₂ content, the thermodynamic property of WPU was significantly improved. When CO₂ content increased from 23.50 wt.% to 31.50 wt.%, the tensile strength increased from 23.27 MPa to 34.63 MPa and the elongation at break decreased from 750.85% to 520.37%, accompanied by the glass-transition temperature increased from -49.7 ℃ to -34.5 ℃. In addition, it was found that WPU prepared by transparent PPCD has better tensile strength, transparency, and storage stability. A new inspiration was provided for its application in the fields of optical components, transparent medical materials and UV curable coatings.

With continuous growth of electric vehicles, the graphite- based anodes cannot fulfill the need for higher energy densities. Lithium ((Li)) anode has shown to satisfy this requirement. However, the aggressive nature of (Li) towards liquid electrolytes and continuous growth of (Li) dendrites hinder its scalability. To resolve these issues, safer electrolytes including polymers and ceramics were studied. Polymer electrolytes, especially polyethylene oxide (PEO), have gained interest for their promising features. PEO shows the highest ionic conductivity (σ) among polymers but suffers from high crystallinity and temperature sensitivity of mechanical strength. On the contrary, thermoplastic polyurethanes (TPUs) show high mechanical stability at elevated temperature despite showing lower σ. Here, the two polymers were blended with the composition of TPU: PEO (30: 70) to improve PEO’s thermomechanical strength. Graphene oxide (GO) and MXene, as layered nanoparticles, were subsequently added to the blend to improve its σ and solubility of the (LiTSI) salt. The nanoparticles increased σ by two orders of magnitude from ({10}^{-5} S/cm) to ({10}^{-3} S/cm). The fast ({Li}^{+}) transportation also led to a rise in ({Li}^{+}) transference number from 0.329 to 0.501. The stable charge- discharge cycles also revealed the effective ({Li}^{+}) transportation.

The use of renewable bio-based monomers to prepare polyisobutylene-based polymers can not only reduce the dependence on petroleum resources but also promote the green transformation of the cationic polymerization industry. Herein, 2-chloro-2,4,4-trimethylpentane (TMPCl) was synthesized as the main initiator and then cooperated with co-initiator TiCl₄ to construct a cationic initiation system, which was successfully used in preparing poly(isobutylene-co-β-myrcene). The effects of co-initiator concentration, monomer concentration and monomer feed ratio on the copolymerization of isobutylene (IB) and β-myrcene were investigated. The results showed that the molecular weight (M_n) first increased and then decreased with elevating the concentration of TiCl₄. When the monomer concentration was 15 wt% and the monomer feed ratio (mole ratio between IB and β-myrcene) was 98:2, an IB-co-β-myrcene random copolymer with a molecular weight of 7.3 × 10³ g/mol and a lower T_g (-67.97 ℃) was obtained. According to the ¹H NMR analysis of the polymer structure and terminal groups, it was suggested that IB and β-myrcene mainly formed the copolymer with 1,4 structural unit under this initiation system, thus the cationic polymerization mechanism of IB and β-myrcene was further proposed. This work can provide basic data and theoretical guidance for the manufacture of greener polyisobutylene-based polymers in the future. 

Phosphorus and potassium are essential macronutrients, and potassium dihydrogen phosphate, a compound containing both, plays a vital role in plant growth and reproduction. However, its rapid leaching poses significant environmental concerns, lessening its practical utility. To overcome this issue, a biodegradable hydrogel based on amla was synthesized through graft polymerization and evaluated as a water-retaining material for agricultural applications, specifically for the controlled release of fertilizers. The synthesized hydrogel was characterized using FTIR, SEM, XRD, and TGA. Its swelling properties, water retention capacity, porosity, and density were also examined. The biodegradable nature of the synthesized hydrogel was confirmed via soil burial and composting techniques, with FTIR used to validate the degradation. The hydrogel degraded almost entirely within 64 days in compost soil and 72 days in burial soil. Finally, potassium dihydrogen phosphate release studies were conducted, and the data were analyzed using Fick’s law of diffusion and various kinetic models (zero order, first order, Higuchi, and Korsemers Peppas). The release pattern was measured via UV spectrophotometry over 45,000 min, demonstrating controlled nutrient delivery. These findings suggested that the synthesized hydrogel matrix has strong potential as an effective water retention system and for regulated nutrient release.

Using molecular dynamics modeling, the change in the conformational structure of the macromolecular corona consisting of two oppositely charged polyelectrolytes, including those combined into one block copolymer, on the neutral and charged surfaces of a cylindrical metal nanowire, as well as on a nanowire polarized in an external transverse uniform electric field is studied. A mathematical model of the conformations of polyelectrolyte chains and block copolymers adsorbed on charged and polarized cylindrical metal nanoparticles is presented. On the uncharged surface of the cylindrical nanowire, macromolecules of oppositely charged polyelectrolytes, including those sequentially connected into one block copolymer, intertwine with each other and form a tightly enveloping corona. On the uniformly charged surface of the nanowire, swelling of the macromolecular corona occurred due to its separation into differently charged coaxial macromolecular layers. When a metal nanowire was placed in an external transversely directed electric field, the macromolecular shell was stratified in the direction of the transverse polarization of the nanowire, and the charged layers of the polymer corona in the polar regions of the nanocylinder swelled.