Macromolecular Chemistry and Physics最新文献

Chitosan and pectin are employed here in the formation of biodegradable hydrogels. The addition of cellulose nanowhiskers (CNW) into the hydrogels is accomplished through two methods: by swelling, after the polymeric network formation (Method A), and inclusion in polymer solutions before gelation, with varying CNW content (Method B). Comprehensive physico–chemical, thermal, microscopic, gel fraction, and water vapor transmission analyses are conducted, complemented by antibacterial and viability assessments. CNWs are successfully synthesized and incorporated within the hydrogel by both methods. Moreover, the degradation temperature (T_max) of hydrogels is higher with CNW (0% CNW: 205.5 °C, 10% CNW: 217.0 °C). CNW aggregates are observed in hydrogels with 20% and 30% content but no aggregation is observed with 4% and 10%. The antimicrobial properties are not affected by the addition of CNW, and the cytotoxicity tests reveal better results with 10% CNW compared with 20%. The study signifies the versatility of CNWs as effective reinforcements, influencing structural, thermal, and biological aspects of the hydrogels. The proposed methodology, emphasizing CNW incorporation, lays the groundwork for innovative biomaterials with promising medical implications. This investigation encourages further exploration and validation of these composite hydrogels in vivo for practical medical use in wound dressings.

Agarose nanofiber with a diameter of 68 ± 33 nm is first prepared by electrospinning under an optimized condition of solvents with hexafluoroisopropanol/water (92.5/7.5, v/v). The results show the control of hydrogen bonding, which is important to prepare a nanoscale agarose material.

This review article explores the recent innovations in the field of antimicrobial and antiviral macromolecules. With the rising challenge of antibiotic resistance, as well as the overuse of antibiotics, there is a growing demand for efficient solutions to combat microbial and viral infections. The development of new effective antimicrobial and antiviral agents is highlighted. This review is designed to give a comprehensive view of the literature focusing on a few examples of combating microbial and viral infections in each section. A brief description of naturally occurring organic-based materials that exhibit antimicrobial and/or antiviral activities is presented, focusing on polysaccharides, peptides, and proteins. Synthetic organic-based materials are divided into subsections including polymers, dendrimers, and nanomaterials. The synthesis and applications of inorganic materials such as polyphosphazenes and polysiloxanes, as well as tin-, germanium- and gallium-based materials are emphasized in this review. Organometallic macromolecules are also described, and their antimicrobial and antiviral activities are examined. Overall, this article provides a comprehensive overview of recent advancements in the design of antimicrobial and antiviral macromolecules, offering valuable insights into their potential applications in biomedical research and combating drug-resistant microorganisms and viruses.

The article discusses the polymerization scheme of benzoxazine monomer based on 4,4′-diaminodiphenylmethane (P-ddm) and the chemical structure of polybenzoxazine based on it poly(P-ddm). The polymerization behavior of benzoxazine P-ddm is studied using differential scanning calorimetry (DSC). Solid-state ¹³C MAS NMR is used to determine the chemical structure of poly(P-ddm). It is revealed that the сhemical structure of poly(P-ddm) predominantly consists not of phenolic Mannich bridges, as expected, but of methylene bridges, which indicates the process of deamination of phenolic Mannich bridges. However, no weight loss associated with the expected release of free amine during this process is detected. This may indicate the incorporation of a diamine moiety into the polymer chain through the formation of imine bonds, the signal of which is detected in the ¹³C MAS NMR and FTIR spectra of the poly(P-ddm), and on the ¹H and ¹³C NMR spectra of model polybenzoxazine based on p-cresol and 4,4′-diaminodiphenylmethane poly(pC-ddm). Based on the data obtained, a hypothesis is put forward about the formation of a network polymer, the structure of which consists mainly of methylene and imine units.

During the utilization of silicone rubber, excessive friction can cause damage to the contact surface and the material itself. Therefore, friction-reducing modification of silicone rubber has attracted much attention. In this paper, hyperbranched polysiloxanes with different structures is synthesized for friction-reducing modification of silicone rubber. Infrared spectroscopy, nuclear magnetic resonance spectroscopy, and amine titration tests reveal that hyperbranched polysiloxanes are successfully synthesized by the hydrolytic condensation of 3-aminopropyltriethoxysilane and their Michael addition with four acrylates with different alkyl chains. The friction coefficients and mechanical properties of silicone rubber are evaluated. Hyperbranched polysiloxanes significantly reduces friction and maintained excellent mechanical properties of silicone rubber. Silicone rubber with butyl-ester-secondary-amino hyperbranched polysiloxane displays the best overall performance, with static and dynamic friction coefficients decreasing by 33.99% and 43.16% compared with that of pure silicone rubber, respectively, and a tensile strength of 10.80 MPa. The friction-reducing mechanism of hyperbranched polysiloxanes on silicone rubber is investigated by contact angle test and dynamic mechanical analysis. Hyperbranched polysiloxanes migrates to the surface due to the incompatibility of alkyl chains with silicone rubber matrix. Consequently, the shielding effect produced by hyperbranched polysiloxanes on the surface depresses the adsorption activity of silicone rubber surface thereby reducing friction.

Water-dispersible fluorescent nano-/microspheres have been widely used as fluorescent probes in many fields. In this paper, aldehyde-functionalized fluorescent micelles are synthesized by self-assembly of end-modified hyperbranched poly(m-phenyleneethynylene-alter-p-phenyleneethynylene)(hb-PMPE). First, hb-PMPE with -Br end-groups(hb-PMPE-Br) is obtained by the polymerization of AB₂ monomer PhBr₂–C≡C–Ph–C≡CH, then the reaction of hb-PMPE-Br with 4-ethynylbenzaldehyde (EBA) gives end aldehyde-functionalized hyperbranched polymer hb-PMPE-CHO. Hence, hb-PMPE-CHO is reacted with aminooxy methoxypolyethylene glycol-2000 (NH₂O-MPEG2000) to link poly(ethylene glycol) (PEG) chains to the ends of hb-PMPE-CHO with partial residual aldehyde end-groups, resulting in aldehyde-functionalized amphiphilic polymer hb-PMPE-PEG. Fluorescent micelles with aldehyde-containing fluorescent hb-PMPE core and PEG shell are obtained by self-assembling hb-PMPE-PEG in water. The micelle diameter is determined by the PEG content in hb-PMPE-PEG, which can be controlled by the reaction weight ratio of NH₂O-MPEG2000/hb-PMPE-CHO. When the ratio of NH₂O-MPEG2000/hb-PMPE-CHO > 0.75/1, micelles with a diameter < 50 nm are obtained. The water dispersion of hb-PMPE-PEG-1/2 micelles (28.9 nm) emits bright green fluorescence with λ_max ≈ 490 nm under UV irradiation, and the emission intensity increases with increasing concentration.

Hybrid single crystals (HSCs) of different poly(ε-caprolactone) (PCL) homopolymers with a poly(ε-caprolactone)-b-poly(ethylene oxide) (PCL-b-PEO) block copolymer (BCP) are prepared. The effects of PCL length, PCL/PCL-b-PEO molar ratio, crystallization temperature (T_c), and solvent on crystal morphology are investigated. The optimal T_c for the formation of more perfect HSCs is between those for homocrystals of individual PCL and PCL-b-PEO and roughly increases with the length of PCL and PCL/PCL-b-PEO molar ratio. The chain folding in the HSCs is studied by comparing the experimentally measured heights obtained by atomic force microscopy (AFM) and theoretically calculated ones based on a sandwich structure model. Under most situations, the PCL homopolymers adopt a larger chain folding number in the HSCs than that in their homocrystals, while the chain folding of BCP remains unaltered. However, when both PCL homopolymer and PCL-b-PEO BCP crystallize slowly and the overcrowding of the PEO is effectively alleviated, thicker HSCs can be formed, in which the PCL homopolymer preserves the chain folding in its homocrystals but the BCP adopts a reduced chain folding number as compared with that in its homocrystals. The relative crystallization rate of PCL homopolymer versus BCP also affects the real composition and overall height of the HSCs.

Front Cover: In article 2300394, Cansen Liu and co-workers construct a polydopamine (PDA) modified MXene-CeO₂@PDA (MCP) filler by a combination of CeO₂ with MXene. The incorporation of MCP filler into waterborne epoxy (WEP) coating leads to the MCP/WEP coating with enhanced corrosion resistance and long-term and stable corrosion protection as compared to the pure WEP coating.