Journal of Polymer Research最新文献

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.

One homo-polymerized (PEsI-a) and four copolymerized (PEsI-b ~ PEsI-e) thermoplastic polyesterimide (PEsI) were prepared from the aromatic diamine of 2-(4-aminobenzoate)-5-aminobiphenyl (ABABP) and the biphenyl-linked dianhydrides of 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (BPDA) and biphenyl dibenzoate-3,3ʹ,4,4ʹ-tetracarboxylic acid dianhydride (BPTME) via the two-step thermal imidization procedure. The obtained flexible PEsI films were casted using the thermally cyclized of poly(amic acid) (PAA) precursors. The PEsI films exhibited the semi-crystalline characteristics and sharp peaks were observed in the X-ray diffraction (XRD) measurements. Meanwhile, the distinct endothermic peaks in the first scanning of the differential scanning calorimetry (DSC) tests were observed. For the copolymerized PEsI-b ~ PEsI-e films, in which the BPTME contents increased in the polymers, the optical transparency of the samples gradually deteriorated until the totally opaque PEsI-e film with a haze of 100% was obtained. The semi-crystalline feature endowed the PEsI films good dimensional stability at elevated temperature, demonstrated by the linear coefficients of thermal expansion (CTE) values from 9.3 × 10^–6/K (PEsI-a) to 25.9 × 10^–6/K (PEsI-e) in the range of 100 ~ 200 °C, the glass transition temperatures (T_g) exceed 216 °C, and the 5% thermal decomposition temperature (T_5%) over 500 °C. In addition, the PEsI samples possess the dielectric strength (D_s) in the range of 220 ~ 230 V/μm, the dielectric constants (D_k) as low as 3.29, and the dielectric dissipation factors (D_f) in the range of 0.0041 ~ 0.0050 at 10 GHz.

A quantitative investigation of phase diagrams in polymer-modified bitumen is essential for understanding its stability, yet this area remains underexplored. This study focuses on styrene–butadiene–styrene (SBS) copolymer modified bitumen as the target material. Rheological methods were utilized to determine the binodal and spinodal lines, resulting in thermodynamic phase diagrams for varying SBS contents that exhibit characteristics of Lower Critical Solution Temperature (LCST). Additionally, optical microscopy was employed to assess the phase separation temperature through the intensity-temperature variation curve. Taking the bitumen/SBS (100/4) combination as an example, the isothermal evolution of phase separation structures at two different temperatures was analyzed. The results indicate that SBS-modified bitumen forms an SBS-rich network structure driven by viscoelastic phase separation, illustrating the dynamic asymmetry between bitumen and SBS. This research enhances our understanding of the phase behavior and dynamics of SBS-modified bitumen, offering valuable insights for the stability study of polymer-modified bitumen.

Soilless culture is gradually becoming a new direction in the development of agricultural cultivation. However, the synthetic substrates currently used suffer from the problems of being nutrient-less and non-degradable, which will ultimately lead to the misuse of chemical fertilizers and serious environmental pollution. In this study, L-Tyrosine(L-Tyr) was used as a nitrogen nutrient modifier, and L-Tyr-PCL-PCDL-PUF/KHA (L-Tyrosine-Polycaprolactone-Polycarbonate-Polyurethane Foam/Kalium Humate, LTPPPK) soilless substrate was prepared by using biodegradable polycaprolactone and potassium humate, a natural plant-stimulating hormone, as raw materials. The experimental results demonstrated that the incorporation of L-Tyr significantly enhanced the LTPPPK material's vesicular pore structure and morphology, characterized by an apparent density of 65.69 kg/m³, a porosity of 85.58%, a pore diameter of 0.96 ± 0.17 mm, a compressive strength of 0.015 MPa, and optimal thermal stability when the L-Tyr content was 3%. Additionally, L-Tyr enhanced the water absorption and retention capabilities, as well as the degradation performance of the material, achieving a maximum water absorption factor of 12.524 g/g. The degradation rate was found to be 10.95% after 6 months of degradation by N435 lipase, indicating that the material is environmentally friendly upon disposal. As a lettuce growing substrate, the LTPPPK material showed a 7.90% and 9.34% growth in root whisker and leaf width compared with the unmodified one after 42 days of lettuce growth, and the content of chlorophyll and soluble protein increased by 4.46% and 16.42%. It was shown that LTPPPK material can provide a certain amount of nitrogen and potassium for plant growth when used as lettuce cultivation substrate.

The stretchable, biodegradable, thermos-responsive, biocompatible and novel poly(1,3-propylene sebacate)-co-poly(glycerol sebacate) polyurethanes (PPGSU), based on poly(glycerol sebacate) (PGS) and poly(1,3-propylene sebacate) (PPS), were synthesized using simple solvent-based two-step method. The comprehensively properties of PPGSU, including the chemical structure, crystalline structure, thermal stability, mechanical performance, water absorption, degradation behavior, drug release behavior, temperature-responsive shape memory effect, as well as biocompatibility were investigated in detail. The impact of the different ratio of PPS and PGS on the properties of final PPGSU product was also studied. The introduction of PPS in the poly(glycerol sebacate urethance) (PGSU) system could increase the glass transition temperature (T_g) and stretchability. The PPGSU polymers showed adjustable tensile strength ranging from 0.5 MPa to 1.3 MPa, as well as the degradable rate and shape memory effect. Furthermore, these elastomers exhibited promising in vitro biocompatibility with adult mouse fibroblasts L929 cells, indicative of their potential for medical applications. Additionally, the possible potential application of biodegradable PPGSU elastomers in the field of drug delivery were examined. Overall, this research offers new perspectives on the development of biomaterials with tailored properties for medical applications.

Nanofiltration (NF) is one of the most promising separation technologies of this century. It plays a major role in the chemical, medical, food, and other fields. The separation and permeation performance of NF membranes is closely related to microstructure. In this study, aqueous phase amine monomers are pre-crosslinked during the preparation of NF membranes. Trimesic acid (TMA) is used as a cross-linking agent with polyethyleneimine (PEI), whereby the resulting aqueous-phase monomer is interfacially polymerized with the organic-phase monomer to form a separation layer with internal lithium-ion permeation channels. The physicochemical structure of nanofiltration membranes is analyzed in detail. The pre-crosslinking process is optimized and the NF membrane performance can achieve 97% rejection of MgCl₂, 15% rejection of LiCl, and 34 L m⁻² h⁻¹ permeate flux. The resulting NF membranes also show stable desalination performance in tests with mixed salt solutions. This study provides a new nanofiltration membrane structure and performance optimization scheme, which is favorable for magnesium-lithium separation systems.

Over the past decades, significant efforts have been made to prepare biofilms. These efforts aim to achieve biopolymeric films from fruits and vegetables waste with soluble and biodegradable new films. In the current study, biopolymeric films were prepared by the starch extracted from banana peel and potato peel and the mechanical and physical properties of the prepared samples were studied. The mechanical property showed that tensile strength decreased by increasing the banana peel starch content whereas the percentage elongation at break was increased. The swelling studies revealed that the weight of the films increased when the film was soaked in distilled water. Biodegradation studies showed biopolymeric films with potato peel composition of was 60% (P60) and 100% (P100) were completely degraded in 16 days. Thermogravimetric analysis (TGA) results indicated an increase in the degradation rate compared to the biofilms prepared using neat banana and potato peel starch. Scanning electron microscopy (SEM) images suggesting two-phase morphology which shows incompatibility of the blends prepared by potato and banana starch. The pure potato peel-based starch film showed good results compared to other compositions as well as neat banana peel starch based films. Based on the results obtained for 100% potato peel shows higher values compare to other compositions. The results suggested that the prepared biopolymeric films could be mainly used in wrapping applications and food packaging where load bearing properties is of least importance.

Chitosan and pectin form biocompatible polyelectrolyte complex hydrogels. This study investigates the impact of cellulose nanowhiskers (CNW) and NaCl on hydrogel’s properties, particularly in mechanical behavior. Swelling tests revealed deswelling under physiological conditions. Thermal analysis indicated enhanced crosslinking with CNW, correlating with mechanical, rheological, and nanoindentation findings. Hydrogels with 10% CNW exhibited higher elastic modulus in compression tests. Rheological studies showed comparable values to skin, promising for wound dressing applications. Nanoindentation highlighted CNWs' surface effect on adhesive modulus. Degradation tests over 21 days demonstrated higher degradation in NaCl-containing hydrogels. Overall, NaCl influenced polymer matrix interactions, while CNW incorporation enhanced hydrogel performance. This study distinguishes between surface and bulk properties of hydrogels, underscoring the potential of CNW in biomaterial applications.