The International Conference on Polymer, Composites, and Nanocomposite-Based Materials (ICPCNB 2023).
The International Conference on Polymer, Composites, and Nanocomposite-Based Materials (ICPCNB 2023).
This study addresses the dual imperatives of sustainability and flame-retardant safety in high-performance polymers by utilizing nucleobases—specifically adenine—as renewable biobased monomers for the synthesis of a new series of polyimides. Among the synthesized polyimides, the one derived from the polymerization of the adenine-derived diamine (ADA) with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), referred to as ADA-6FDA, exhibits outstanding performance, with a glass transition temperature (T g) exceeding 356°C, a low coefficient of thermal expansion (CTE) of 25.2 ppm K−1, and a remarkable limiting oxygen index (LOI) of 52%. These results indicate that the adenine structure imparts thermomechanical properties comparable to or superior to those of petroleum-based polyimides. At the same time, the high nitrogen content provides an intrinsic flame-retardant pathway through the release of inert gas and the formation of char. This heterocyclic contribution to high flame retardancy is also evidenced by a series of reference polyimides comprising aromatic or isosorbide-based diamines. This work establishes a sustainable class of polyimides that combines high performance with enhanced safety, offering an eco-friendly alternative for advanced electronic and aerospace applications.
In this work, the effects of the interaction between the blowing and nucleating agent content on nucleation efficiency and cell structure were investigated, the growth process of the cells was observed using visualization equipment, and the nucleation process was fitted. The results demonstrated that the addition of ZIF-8 nucleating agent at low blowing agent content (1.5 wt.%) significantly increased the cell density from 5.61 × 103 to 2.80 × 105 cells/cm3, and the cell size decreased from 372.6 to 86.2 μm. At high blowing agent content (4.5 wt.%), the nucleating agent addition resulted in only a modest increase in cell density, from 2.98 × 106 to 6.61 × 106 cells/cm3. The reduction in cell size was also less pronounced, decreasing from 48.65 to 32.49 μm. Simultaneously, foam samples were prepared using the core-back technology for engineering verification, which exhibits excellent consistency with the visualization observations. Additionally, these results also revealed that the gas concentration was a key factor governing cell nucleation when the nucleating agent content was low. However, the heterogeneous nucleation mechanism played a dominant role under high nucleating agent content conditions, significantly reducing the nucleation energy barrier to enhance nucleation efficiency.
To address the flammability issue of CO2-based polycarbonate (PPC), this study synthesized a phosphorus-containing flame retardant via the addition reaction of maleic anhydride (MA) and lowly oxidized diphenyl phosphine oxide (DPO), and further prepared a high-phosphorus-content flame-retardant functional CO2-based polycarbonate material (PPCO) by incorporating this monomer as the third component in ternary copolymerization of CO2 and propylene oxide (PO). Performance testing revealed that the thermal properties of PPCO significantly improved with increasing content of the phosphorus-containing monomer. Compared to PPC, its 5% weight-loss degradation temperature (T d,−5%) and maximum weight-loss degradation temperature (T d,max) increased by 96°C and 93°C, respectively, while the glass transition temperature (T g) reached 46°C. In terms of mechanical properties, the tensile strength of PPCO increased by 15.9 MPa and Young's modulus improved by 4.3-fold relative to PPC. Most importantly, PPCO exhibited outstanding flame retardancy, achieving a limiting oxygen index (LOI) of 33.9% and meeting the UL-94 V-0 rating (no dripping). This research provides new insights for developing high-performance flame-retardant polycarbonate materials, and PPCO shows potential applications in flame-retardant materials for building exteriors and the electronics industry.
Water-lubricated bearings are prone to severe abrasive wear under low-speed and heavy-load conditions. Therefore, developing ultra-high molecular weight polyethylene (UHMWPE) composites with superior wear resistance is crucial for water-lubricated bearings. Herein, the tribological behavior of a novel UHMWPE/Silicon dioxide/Molybdenum disulfide (SiO2/MoS2) composite was investigated through a combined experimental and molecular dynamics (MD) simulation. The results demonstrated that the synergistic effect of SiO2 and MoS2 significantly improves the tribological properties of UHMWPE. Compared to pure UHMWPE, the composite exhibits a 62.96% reduction in wear rate and achieves an average friction coefficient as low as 0.044. Furthermore, MD simulations visually reveal the synergistic lubrication mechanism formed at the friction interface due to the structural differences between the two fillers, effectively enhancing interfacial slip between the composite and the counterpart ball.
Porous polymers were successfully synthesized via conventional radical polymerization of multifunctional methacryloyloxy phosphate monomers, bis[2-(methacryloyloxy)ethyl] phosphate (BMEP) and phosphoric acid 2-hydroxyethyl methacrylate ester (PHME), in tetrahydrofuran (THF) through polymerization-induced phase separation. Polymerizations of BMEP in various alcohols such as 1-propanol, 1-butanol, and n-hexanol at appropriate monomer concentrations also yielded porous networks. The resulting polymers exhibited monolithic morphologies composed of interconnected spherical particles with diameters of 1–2 μm. These porous monoliths were mechanically robust, showing no fracture under compression up to 50 N, and demonstrated excellent thermal stability, beginning to decompose around 280°C under both argon and dry air atmospheres while leaving 40–50 wt% residues at 500°C. The presence of phosphate groups within the polymer backbone effectively imparted flame retardancy to the materials.
High sulfur composites are crosslinked networks in which oligo- and polysulfide catenates connect organic units and can be post-modified via labile S–S bonds. Building on our demonstration that aryl dithiols raise the glass transition of GS 80 (made by heating 80 wt% sulfur and 20 wt% guaiacol), we establish structure–property rules by varying dithiol identity—butane-1,4-dithiol (BuDT), hexane-1,6-dithiol (HDT), benzene-1,4-dithiol (BDT), biphenyl-4,4′-dithiol (BPDT), and naphthalene-1,5-dithiol (NDT)—and GS 80 :dithiol mass ratio (10:1 to 2:1). Twenty five compositions were characterized by thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Aromatic dithiols raise decomposition temperature (T d) and promote carbonization: at 2:1, T d = 326°C–333°C with 20–27 wt% char; at 10:1, T d = 300°C–313°C; char = 5–7 wt%. Aliphatic dithiols are weaker modifiers: HDT gives T d = 262°C–269°C with 7–15 wt% char, whereas BuDT yields T d = 250°C–268°C and ≈0–1 wt% char, consistent with S–Caryl formation above 220°C anchoring higher boiling HDT but not more volatile BuDT. Glass transition temperature (T g) is tunable over 73°C, from −48°C (HDT, 2:1) to +25°C (NDT, 2:1), with aliphatic dithiols acting as plasticizers and aromatic dithiols stiffening the network in near linear proportion to loading. These results deliver quantitative, mass-ratio-based compositions for targeting T d, char yield, and T g in post-modified high-sulfur composites.
The cover image is based on the Article Hybrid Nanoparticles Separated by Buoyant Density in a Large-Scale Centrifugal Process by Alexander Wittemann et al., https://doi.org/10.1002/pol.20250248.
The cover image is based on the article Editorial: Celebrating 50 Years of Macromolecular Chemistry and Polymer Research at the University of Bayreuth by Andre Gröschel et al., https://doi.org/10.1002/pol.20250928
A metal-free and sustainable strategy for the synthesis of graft copolymers was developed by combining ring-opening polymerization (ROP) of ε-caprolactone with atom transfer radical polymerization (ATRP) at ambient temperature. Polycaprolactone (PCL) backbones bearing initiating sites were first prepared and subsequently employed for ATRP of two different vinyl monomers, methyl methacrylate (MMA) and poly(ethylene glycol) methyl ether acrylate (PEGA). This tandem polymerization approach enabled the controlled preparation of well-defined PCL-g-PMMA and PCL-g-PPEGA graft copolymers without the use of transition-metal catalysts. The successful incorporation of side chains was confirmed by 1H-NMR and FT-IR spectroscopy, while molecular weight distributions were evaluated by gel permeation chromatography (GPC). Differential scanning calorimetry (DSC) revealed the influence of grafting on the thermal properties of the copolymers, and water contact angle (WCA) measurements demonstrated surface wettability changes associated with PEGA incorporation.
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