Polymer Bulletin最新文献

The depletion of global petrochemical resources, coupled with the environmental challenges arising from the extensive use of traditional plastics, has led to greater interest in the research of environmentally friendly biodegradable materials that can be used in various applications. The weak water barrier properties of collagen hydrolysate (CH) obtained from leather industry trimming waste seriously limit its practical application areas. In this study, CH/sodium alginate (CH/SA)-based films were produced using the solution casting method because they are non-toxic and biocompatible. The CH/SA composition with the best water barrier property was selected and cross-linked with transglutaminase (TG), genipin (GP), and tannic acid (TA). Cross-linking significantly increases the mechanical strength, thermal ability, and hydrophobicity of the films, thereby reducing their WVP and WS. The film sample CH40/SA60/GP^0.4%, out of all the examined specimens, demonstrated superior overall performance, characterized by a TS of 21.209 MPa and a WS of 19.896%. The results indicate that biodegradable films serve as a promising foundation for the development of packaging materials. Consequently, this study offers an effective approach to creating high-performance, environmentally friendly, and degradable CH/SA-based films and products.

This study explores the mechanical, thermal, and water absorption properties of environmentally friendly polymer composite rebar, created using locally discarded vegetable waste biochar and areca fiber. The material underwent various characterization following ASTM standards in order to evaluate its suitability for construction applications. The integration of biochar and areca fiber aims to improve both the sustainability and performance of the composite rebar. Scanning electron microscopy (SEM) images were analyzed to offer insights into the material's microstructure and morphology behind the performance change. From rebar composite ‘C,’ with 2 wt% biochar and 40% areca fibers, superior load-bearing capacity was observed with a tensile strength of 58 MPa, flexural strength of 99 MPa, and compression strength of 75 MPa, indicating enhanced mechanical performance. In contrast, rebar composite ‘E’ exhibited notable shore-D hardness of 81 due to excessive biochar content, enhancing material rigidity. The increased biochar content positively influenced the thermal conductivity of the composite rebar material, with the collaborative effect of areca fibers and biochar particles enhancing overall thermal performance. Consequently, rebar composite ‘E’ displayed a thermal conductivity value of 0.544 W/mK. Water absorption behavior in the rebar composites was influenced by 1 µm-sized biochar particles, rendering them hydrophobic. Despite the natural hydrophilic nature of areca fibers, the biochar content intensified hydrophobic behavior. Rebar composite ‘E,’ with 8 wt% biochar, exhibited minimal water absorption at 0.0009. In the three-point bending strength analysis of beams constructed with rebar composites, ‘C’ rebar-made beams demonstrated robust bending strength at 29.6 MPa. This heightened strength is attributed to the structural strength inherent in the ‘C’ rebar composite, enabling effective resistance and absorption of applied loads. Therefore, this overall characterization provides valuable insights into the performance of the eco-friendly polymer composite rebar, establishing their potential for sustainable construction practices.

The dependency of molecular weight of polymer solutions at different concentrations has been studied using the Dynamic light scattering method. The correlation data were collected at two scattering angles 175° and 90° along with the 1 M NaCl solutions. Analysis shows the existence of two modes, namely, fast and slow, for all the solutions. Analyses of angle dependent study quantify the existence of homogeneity and heterogeneity in the solutions which results from the fact that when the separation of β value between aqueous and 1 M NaCl is very low, 1 M NaCl has almost no effect on the change in the hydrodynamic layer compared to the higher separation value of β when the same effect of 1 M NaCl was significantly observed. Further, analysis of correlation data suggests that with the increase in molecular weight and concentration of the polymer solutions, the homogeneity of the solutions increases decreasing its existing heterogeneity. These aspects of polymeric solutions are more prominently observed and further verified by comparing the results of aqueous and 1 M NaCl solutions. Interestingly, our result also shows an optimization method of homogeneity and heterogeneity by tuning molecular weight and concentrations in both aqueous and 1 M NaCl solutions.

Hydrogen peroxide (H₂O₂) has practical applications in healthcare, food security, and environmental protection. The current study has been focused on creating H₂O₂ sensors using a bimetallic composition of polypyrrole/Cobalt-silver on indium tin oxide (ITO) through electrochemical fabrication. Composite hybrid materials comprising Co@Ag/PPy/ITO were successfully synthesized using chronoamperometry and pulsed electrodeposition techniques. The obtained electrode (Co@Ag/PPy/ITO) was studied using scanning electron microscopy (SEM), ultraviolet–visible, and cyclic voltammetry techniques. The energy-dispersive X-ray spectroscopy and SEM revealed that silver and cobalt nanoparticles were distributed on the PPy surface, forming fern-like structures. A detailed investigation of the electrochemical properties of the bimetallic composition was conducted using cyclic voltammetry (CV), chronoamperometry, and electrochemical impedance spectroscopy. The amperometric method and CV were used to carry out the electrochemical detection of H₂O₂. The non-enzymatic H₂O₂ sensor exhibited an enhanced amperometry response, showing a higher sensitivity of 3.664 mA mM⁻¹ cm⁻² within a linear range spanning 0.12–2.36 mM. Notably, the sensor achieved a low detection limit of 1.985 μM (S/N = 3). Additionally, the nanocomposite hybrids demonstrated superior stability, repeatability, and reproducibility, making this sensor suitable for long-term use.

Essential oils are a vast class of compounds that have many interesting therapeutical properties. In this sense, tea tree oil (TTO) stands out for its antioxidant, antifungal, antibacterial, anti-inflammatory, and antihyperproliferative potential. However, the low stability and solubility of these compounds can limit their therapeutical capacity, making it necessary to adopt a strategy to overcome this mishap. In that regard, nanoencapsulation can be highlighted as a promising maneuver capable of protecting the active and increasing its solubility in water, promoting greater compatibility and bioavailability. Based on the above, the main objective of this study was to evaluate polycaprolactone/Pluronic F-127 PCL/F-127 polymeric nanoparticles loaded with 10–30% w/w TTO obtained via nanoprecipitation. The obtained particles were evaluated by atomic force microscopy and UV–Vis spectroscopy to determine retention efficiency and obtain the release profile (with the evaluation of release models), time-domain nuclear magnetic resonance, antimicrobial activity, and cytotoxicity in fibroblasts and epithelial cells. The obtained results show the formation of particles of spherical-type morphology particles with smooth surfaces and particle sizes around 400 nm, with retention efficiencies between 60 and 70% and sustained release profile for up to about 6 or 7 h and compatible with the Higuchi model. Regarding the antimicrobial activity of the systems, it was observed that TTO presents antimicrobial activity against the evaluated strains (S. aureus, C.albicans, and E.coli) and that the encapsulation process can increase the activity against the strain of E. coli. Finally, the cytocompatibility analyses showed that the NNPs obtained are not cytotoxic to the cell lines evaluated.

In this study, modification of regular masks using composite nanofibers containing porous nanostructures has been considered in order to increase their efficiency in dealing with new threats. For this purpose, polystyrene was used as a low-cost polymer to prepare nanofibers and modify the surface of the respirator mask. ZIF-8 nanostructures with different sizes (14, 23, 65,144, and 265 nm) and zinc oxide nanoparticles, with an approximate size of 36 nm, were added to polymer nanofibers.2-methyl imidazole and Zn(NO₃)₂ were used to synthesize nanostructures. Two different methods (injection and stabilization) were used to incorporate nanostructures into fibers. The percentage of ZIF-8 and ZnO nanostructures were 0.5 and 2 wt% respects to polystyrene, respectively. Synthesis reactions and preparation of fibrous filters were carried out at ambient temperature. FESEM, FTIR, EDAX, TGA, and XRD techniques were used to identify the prepared nanoparticles and fibers. To evaluate the performance of the modified filters, their efficiency in removing suspended particles below 2.5 microns as well as CO₂, SO₂ and NO₂ gases was surveyed. The results showed that ZIF nanoparticles with arbitrary sizes have been synthesized and successfully stabilized on the surface of nanofibers. Modifying the surface of the commercial mask by electrospinning method resulted in forming a fibrous layer with an approximate diameter of 700 nm and the presence of stabilized nanostructures in both methods was confirmed using FESEM images. Adding the nanofibers to the surface of the filter significantly increased their efficiency in removing suspended particles and toxic gases. The optimized modified filter contained ZIF-8 with14nm dimension and could remove sub-micron particles, CO₂, NO₂, and SO₂ gases by 99, 91, 87, and 86%, respectively, making it as effective as commercially available N-95 masks. Moreover, it was observed that the incorporation of nanostructures by the stabilization method was more effective in improving the filtering efficiency of the fibrous mask.