Journal of Polymer Science最新文献

The market need for black polyimide (BPI) in microelectronics and optoelectronics has significantly increased. However, the current BPIs suffer from issues such as inadequate masking effectiveness, inferior electrical performance, and dimensional stability. 3,6-Di(furan-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (DBF) is a typical dye that possesses excellent light-absorbing ability. In this work, a novel diamine (DBFRFPDA) with DBF-derived chromophores was successfully synthesized. Utilizing this newly developed diamine and pyromellitic dianhydride (PMDA), an inherent BPI (DBFRFPPI) was prepared. The spectral absorption of DBFRFPPI is greatly widened and red-shifted with the incorporation of DBF-based chromophores, thus achieving an exceptionally dark hue. DBFRFPPI exhibits a high cut-off wavelength (λ _cut) of 680 nm and a small CIE-Lab coordinate L* of 1.02. Moreover, DBFRFPPI shows a small coefficient of thermal expansion (CTE) and demonstrates outstanding thermal and electrical characteristics. The electronic transitions of DBFRFPPI were investigated using density functional theory. The findings demonstrate that the superior light absorption of DBFRFPPI is chiefly derived from the HOMO→LUMO+1 transition, which takes place within the DBF-based chromophore moiety. This intrinsic BPI with highly comprehensive properties has important applications in microelectronic fields, especially in flexible copper-clad laminate (FCCL).

Fibers with electrostatic capture properties and bimodal structures, combining fibers of different diameters, offer innovative filtration approaches with low-pressure drop and high efficiency. In this study, PA6 and dielectric PVDF nanofibrous mats, positioned differently in the triboelectric series, are produced via the electro-blowing technique. To identify the most effective factors influencing filter performance, four groups are prepared: unimodal single-layer filters, group X (fibers with the same diameters but different polymers for triboelectric effect), group Y (fibers with different diameters and polymers for bimodal + triboelectric effects), and group Z (fibers with only different diameters for only bimodal effect). The unimodal PVDF mats show 100% higher surface potential and the highest filtration efficiency (99.233%) among single-layered samples. Multi-layered samples perform better, with the four-layered bimodal PA6/PVDF showing the greatest efficiency improvement due to both bimodal structure and triboelectric effect. After corona charging, sample Y3's filtration efficiency increases from 99.886% to 99.997%, with minimal change in pressure drop. After one month and IPA treatment, it retains a surface potential of −0.26 kV and 99.829% efficiency. The higher surface potential of group Y confirms the triboelectric effect, while its superior performance highlights the advantages of bimodal and electret effects.

Trial Registration: Not applicable, as this study does not involve a clinical trial.

Due to its excellent biocompatibility, high-temperature resistance, chemical corrosion resistance, radiation resistance, and ease of processing and shaping, polyether ether ketone (PEEK) has been widely used in the field of oral medicine. In this study, we conducted an in-depth investigation of the thermal annealing process of PEEK films at different temperatures. The grazing incidence wide-angle x-ray scattering (GIWAXS) results indicate that the PEEK molecular chains tend to align in an edge-on orientation in the film, and annealing at different temperatures leads to the formation of two crystalline phases, A and B, with a spacing of 4.46 Å for (200) A and 4.69 Å for (200) B. The crystallization behavior during the annealing process was characterized using in situ GIWAXS, revealing an increase in the film's crystallinity in the early stages of annealing. Due to enhanced polymer chains mobility, the B phase is formed. However, during annealing at 200°C, the intensity of the (200) B peak initially increases and then decreases, indicating the instability of the B phase, which can be disrupted by excessive molecular mobility. Mechanical property characterization results demonstrate that as the annealing temperature increases, the film's elongation at break and modulus decrease.

Simultaneously increasing mechanical strength, toughness, thermal stability, and flame retardancy of epoxy thermoset without compromising transparency is appealing but challenging. To address that goal, a Schiff base epoxy VDEP is developed. The neat VDEP-cured product, VDEP_100wt%, not only shows comparable mechanical strength to conventional epoxy thermoset but also can be degraded in 10% H₂SO₄/THF/H₂O solution in 24 h, showing great degradability under mild conditions. More importantly, proper addition of VDEP simultaneously increases the tensile strength, impact strength, T _g, T _d5%, char residue, and UV shielding of cured epoxies while providing self-extinguishing ability. All of those enhancements are achieved without deteriorating transparency. When 15 wt% of VDEP is added, the tensile strength reaches 91.07 MPa, with a 36.7% increase; the impact strength reaches 40.73 kJ m⁻², with a 33.8% increase. The enhancement in mechanical strength is due to the reinforcing effect of intermolecular interaction and compacted network caused by free volume reduction. The higher toughness results from greater mobility of chain segments, reduced crosslinking density and energy dissipative intermolecular interaction. The rigid two benzene-conjugated Schiff base structure and abundant hydrogen bonding contribute to higher T _g. Therefore, this work provides a degradable Schiff base epoxy and high-performance thermoset based on it.

Pressure-sensitive adhesives (PSAs) are widely used in daily life, but their poor degradability poses significant challenges to sustainable development. To address this, we synthesized a polycarbonate, PPCB, using carbon dioxide and propylene oxide as raw materials, incorporating rigid benzene rings and ester functional groups. PPCB exhibited a T _d,−5%, and T _d,max that were 58.5% and 30.7% higher than those of polypropylene carbonate (PPC), respectively. Its highest tensile strength was 55% higher than PPC, while its elongation at break decreased from 421% to 165%. The 180° peel strength of PPCB reached 5.2 ± 0.56 N/cm, surpassing that of some commercial products such as Duct-tape. PPCB demonstrated high and stable adhesion strength (~52 N) on various substrates. Its adhesion strength to skin tissue was 26.6 ± 1.6 kPa, significantly higher than that of commercially available fibrin glue. Rheological studies indicated that PPCB maintained high viscosity throughout the testing process, with a lap shear strength close to 4.56 MPa. Additionally, PPCB showed excellent degradability, with a high water absorption rate and significant weight loss. PPCB also exhibited good biocompatibility, with a cell viability rate greater than 90%. PPCB has the potential to become a novel degradable PSA, providing a new solution for environmental sustainability.

This study presents a work on the aminolysis of propylene carbonate (PC) and the influence of protic and aprotic solvents, a relatively scarce topic in the existing literature. In this work, di-hydroxy terminated di-carbamate/hydroxyurethanes (HUs) have been synthesized employing an environmentally benign approach, specifically, the aminolysis of PC with five distinct amines namely, 1,6-hexane diamine (HDA), isophorone diamine (IPDA), diethylenetriamine (DETA), triethylenetetramine (TETA), and tetraethylenepentamine (TEPA), utilized in stoichiometric molar ratios. The obtained HUs can be further utilized for the synthesis of non-isocyanate polyurethanes (NIPUs). The aminolysis of PC with HDA in the presence of a protic solvent (MeOH) resulted in a complete conversion without a catalyst. Notably, when compared to the utilization of an aprotic solvent (DMSO) with catalysts (TBAB, LiCl, LiF, DBTDL, and TEA), the exclusive use of the protic solvent (MeOH) demonstrated superior catalytic activity in the context of ring opening/aminolysis of PC. PC conversion was quantified through ¹H NMR spectra. In depth structural elucidation and molecular weight determination were achieved using ¹H NMR, ¹³C NMR, and GPC analyses. Additionally, DSC assessments were employed to characterize glass transition and melting point temperatures. The utilization of solvents improves the polymer conversion, facilitates the processability of the reaction mixture, and enhances the mobility of the monomers throughout the reaction. The synthesized di-hydroxy terminated di-carbamates exhibit significant potential for applications in wood and metal coatings, films, adhesives, and as curing agents for epoxies.

This study aims to determine the in vitro and in vivo biocompatibility and the differences in LL-37 releasing patterns of the PLC/Col/LL-37 sustained releasing membrane and the rapid releasing Col/LL-37 membrane for use as a barrier membrane in guided bone regeneration. On Days 3 and 7, the PLC/Col/LL-37 membrane revealed generated osteoclasts, whereas the PLC/Col membrane indicated mature osteoclasts. PLC/Col/LL-37 was non-toxic to blood cells and inhibited human albumin adhesion to the surface. A microbial reduction was observed in the Col/LL-37 membrane, while both PLC/Col/LL-37 and Col/LL-37 may have caused early phases of skin sensitization. In animal testing, PLC/Col/LL37 and Col/LL37 exhibited the same levels of inflammation as the control group at all time points, while the different releasing patterns of LL-37 loaded on PLC/Col/LL-37 and Col/LL-37 membranes had no effect on inflammation resolution in rat models.

Lead halide perovskite has currently emerged as a research hotspot in the field of photocatalysis due to its exceptional photovoltaic characteristics. Despite its potential, the susceptibility to degradation under harsh conditions such as light, humidity, and polar solvents poses a significant challenge. To counteract this, a strategy employing silica to shield the perovskite surface is conducted, thereby enhancing its stability. The resulting composite MAPbBr₃@SiO₂ is then deployed as a photocatalyst in the photoinduced electron/energy transfer reversible addition fragmentation chain transfer (PET-RAFT) polymerization of butyl acrylate within polar solvents. The catalytic performance across different RAFT polymerization systems including varying the RAFT reagents, catalyst concentrations, and solvent types is meticulously examined. Remarkably, with a photocatalyst loading of merely 0.004 wt% and under a blue light intensity of 6 mW/cm², over 80% monomer conversion can be achieved in 4 h. Moreover, the molecular weight distribution (Đ) consistently remains within the narrow range of 1.0–1.2 across all experimental setups, which proves the controllable nature of the PET-RAFT process. Owning the advantages of low photocatalyst requirement, compatibility with polar solvents, and narrow molecular weight distribution, PET-RAFT polymerization mediated by MAPbBr₃@SiO₂ holds promise for scalable manufacturing and industrial-scale applications.