Chinese Journal of Polymer Science最新文献

Tumor-associated carbohydrate antigens (TACAs) provide a special class of tumor-specific antigens that show promising applications in cancer immunotherapy. However, the weak immunogenicity and structural complexity of TACAs are obstacles to their clinical application. Here, based on a fast and low-cost purification strategy for oligosaccharide synthesis, the synthesis of tumour-associated carbohydrate antigens Globo H and mannobiose which resembles repeat unit of mannan was achieved. To enhance the immunogenicity and multivalent effect, Globo H and mannobiose were covalently attached to degradable polymer backbones. 2D spindle-like lamellar micelle and globular micelle were obtained from glycopolymer through a solvent-exchange method of self-assembly. The glyconanoparticle showed good biocompatibility and degradability. Immunological functions of these glyconanoparticles such as stimulation of BMDC to cause upregulation of inflammatory factors were preliminarily explored.

The effect of temperature on the electrical conductivity (σ) and Seebeck coefficient (S) of n-type vapor grown carbon nanofibers (CNFs) and poly(vinylidene fluoride) (PVDF) melt-mixed with 15 wt% of those CNFs is analyzed. At 40 °C, the CNFs show stable n-type character (S=−4.8 µV·K⁻¹) with an σ of ca.165 S·m⁻¹, while the PVDF/CNF composite film shows an σ of ca. 9 S·m⁻¹ and near-zero S (S=−0.5 µV·K⁻¹). This experimental reduction in S is studied by the density functional tight binding (DFTB) method revealing a contact electron transfer from the CNFs to the PVDF in the interface. Moreover, in the temperature range from 40 °C to 100 °C, the σ(T) of the CNFs and PVDF/CNF film, successfully described by the 3D variable range hopping (VRH) model, is explained as consequence of a thermally activated backscattering mechanism. On the contrary, the S(T) from 40 °C to 100 °C of the PVDF/CNF film, which satisfactorily matches the model proposed for some multi-walled carbon nanotube (MWCNT) doped mats; however, it does not follow the increase in S(T) found for CNFs. All these findings are presented with the aim of discerning the role of these n-type vapor grown carbon nanofibers on the σ and S of their melt-mixed polymer composites.

Owing to the significant increase in air pollutants and the spread of infectious diseases, it seems that the use of face masks will become an essential item in human societies. Therefore, there is a need to conduct more research to develop novel types of respirators utilizing up-to-date science such as nanotechnology. In this study, we fabricated a nanocomposite fibrous filter containing modified graphene oxide (GO) and zinc oxide (ZnO) nanoparticles. This layer was used as an active filter for absorbing and removing air pollutants, such as suspended submicron particles (below 2.5 microns) and CO₂, NO₂, and SO₂ gases. The synthesized nanostructures and fibrous filters were characterized by different analysis (FTIR, XRD, TGA, and FESEM), and the performance of the filters was surveyed by tests such as pressure drop, CO₂, NO₂, SO₂ gas rejection, and particulate removal. The results showed that the stabilization of the modified GO and ZnO nanostructures on the fibrous filter improved the effectiveness of this filter as a mask for removing toxic particles and gases, and the filter containing nanoparticles had the best performance.

Crosslinking natural rubber (NR) and styrene butadiene rubber (SBR) composites with carbon black (CB) have been utilized in the tire tread industry. A sulfur-based lightly crosslinker can potentially enhance the self-healing capabilities of rubber. Moreover, the rubber composites were studied for non-covalent interactions between the benzene rings of SBR and CB. In this research, rubber samples were prepared, and their structure was investigated using Fourier transform infrared (FTIR), and Raman spectroscopy. The red shift in Raman spectroscopy confirmed non-covalent interaction or hydrophobic interaction between SBR and CB in NR/SBR composites exposed to CB due to environmental change. The differential scanning calorimetry (DSC) thermograms showed that NR and SBR were incompatible. Additionally, the mechanical properties of these rubber blends were enhanced as the proportion of NR increased. The maximum self-healing performance reached 40% for the formulation containing 25 phr NR and 75 phr SBR, which also saved energy with low chain end movements. Therefore, these composites could be utilized as a semi-empirical model for studying crosslinked rubber blends, specifically in the rubber tire industry.

Polyimide (PI) is widely used in high-frequency communication technology due to its exceptional comprehensive properties. However, traditional PI has a relatively elevated dielectric constant and dielectric loss. Herein, the different cross-linked structures were introduced in PI matrix and conducted a detailed discussion on the influence of cross-linking agent content and cross-linking structure type on the overall performance of PI films. In comparison to the dielectric constant of 2.9 of neat PI, PI with an interchain cross-linking structure containing 2 wt% 1,3,5-tris(4-aminophenyl)benzene (TAPB) (interchain-PI-2) exhibited the reduced dielectric constant of 2.55 at 1 MHz. The PI films with intrachain cross-linking structure containing 2 wt% TAPB (intrachain-PI-2) exhibited the lowest dielectric constant of 2.35 and the minimum dielectric loss of 0.0075 at 1 MHz. It was due to the more entanglement junctions of intrachain-PI resulting in decreased carrier transport. The thermal expansion coefficients of both interchain-PI and intrachain-PI films were effectively reduced. Moreover, in contrast to interchain-PI films, the intrachain-PI films maintained colorlessness and transparency as the cross-linking agent content increased. This work compared the effects of two different cross-linked structures on the performance of PI films and provided a feasible way to obtain low-k PI films with excellent comprehensive performance for 5G applications.

Electrospun nanofibrous separators, despite lacking superior mechanical strength, have gained widespread attention with high porosity and facile processing. Herein, utilizing the fact that thermal imidization temperature of poly(amic acid) (PAA) into polyimide (PI) coincides with the pre-oxidation temperature of polyacrylonitrile (PAN) into carbon fiber, we proposed a new cross-electrospinning strategy to obtain a composite nanofibrous separator (PI/oPAN) randomly interwoven by PI and pre-oxidized PAN (oPAN) nanofibers, via synchronously electrospinning the PAA and PAN onto the same collector and then heat-treating for 2 h at 300 °C. The resultant PI/oPAN separator was able to preserve high porosity (71.7%), electrolyte wettability and thermal stability of PI nanofibrous membrane, and surprisingly exhibited high mechanical strength, being 3 times of PI, which mainly because of the numerous adhesion points generated by the melting of PAN in the pre-oxidation process. Meanwhile, the polar groups of oPAN and 3D fibrous network enhanced the PI/oPAN separator’s ionic conductivity and Li⁺ transference number, rendering the corresponding cell with more stable cycling performance than cells assembled with pure PI, PAN or commercial PP separator. Therefore, this work might provide a new avenue for the ongoing design and further development of LIB separators capable of high safety and high performance.