Yan Zhao

Bio: Yan Zhao is an academic researcher from Beijing University of Chemical Technology. The author has contributed to research in topics: Chemistry & Skimmed milk. The author has an hindex of 5, co-authored 7 publications receiving 311 citations.

Antimicrobial activities of hydrophilic polyurethane/titanium dioxide complex film under visible light irradiation

Abstract: Using the polyurethane (PU) resin modified by anion surfactant, the hydrophilic polyurethane/titanium dioxide (TiO 2 ) complex film (HPTF) was prepared. The characteristics of the HPTF were described by Fourier-transform infrared spectrometry (FT-IR), ultraviolet–visible spectroscopy (UV–vis) and standard measurements of mechanical properties. Simultaneously, the antimicrobial activities of the HPTF were also studied. The results indicated that, after 8 h, nearly all of the Escherichia coli ( E. coli ) and Candida albicans ( C. albicans ) could be killed under visible light irradiation; the antimicrobial activity was evidently better than pristine polyurethane film. The antimicrobial ratio of the latter was less than 40% under the same conditions. The optimal TiO 2 amount in the HPTF preparation was 0.25 g (TiO 2 )/100 mL (emulsion). The antimicrobial activity of the HPTF under visible light was in accordance with the UV–vis absorption spectra, in which strong absorption extended over the visible light spectra region. The combination of the dodecyl sulfonate group and titanium dioxide with polyurethane was found via FT-IR.

Antibacterial and anti-mildew behavior of chitosan/nano-TiO2 composite emulsion

Abstract: A novel chitosan/nano-TiO2 composite emulsion (CTCE) was prepared by inverse suspension technol- ogy, and its multi-function properties were studied. As can be seen from the results, the gauze treated with chitosan/ nano-TiO2 composite emulsion showed excellent antibacterial activities against Escherichia coli, Aspergillus niger and Candida albicans that the bactericidal ratios could reach 99.96%, 100% and 78.3% after 24 h, respectively. At the same time, the chitosan/nano-TiO2 composite emulsion could really kill the bacteria, not just inhibit its growth, and the bac- tericidal ratio for E. coli could reach 70.3% after 1 h. The bactericidal ratio for E. coli reached 98.8% at 27 o C com- pared with 58.7% at 18 o C after 8 h due to the activity of bacteria being weakened at low temperature. Furthermore, the antibacterial ability of antibacterial gauze was hardly influenced with the increase of storage time, which could be reused for up to 8 times without loss of antibacterial ability.

Preparation method of antibiotic anti-fungus agent for building surface

Abstract: The invention relates to a preparation method of an antiseptic and mold-proof agent that is used on building surfaces. The preparation method comprises the following steps: the film forming aid, the nanometer TiO2, the dispersing agent, the emulsifier, the multifunctional promoter and the mold-proof promoter are added into the coating solution which is used as a building covering material, dispersed and mixes;, the weight percentage of every components are controlled as: coating solution 20% to 90%, nanometer TiO2 0.1% to 5%, film forming promoter 0.1% to 10%, dispersing agent 0.05% to 0.5%, emulsifier 0.1% to 1%, multifunctional promoter 0.1% to 1%, mold-proof promoter 0.1% to 10% and water 5% to 70%. The mold-proof agent prepared by the invention can be sprayed on the building surfaces at any time to renew catalytic the mold-proof coatings; the application method is simple and flexible, and the mold-proof agent has very good combining power and consistency with the covering materialsof the inner and exterior walls; the mold-proof agent simultaneously makes full use of the synergism of sterilization and mold-proof by the nanometer titanium dioxide catalytic and mold-proof agent;the mold-proof agent can remove the formaldehyde VOC and other volatile gases; the invention has the advantages of simplicity, few addition agents and low production cost .

Emerging Chitosan-Based Films for Food Packaging Applications

Abstract: Recent years have witnessed great developments in biobased polymer packaging films for the serious environmental problems caused by the petroleum-based nonbiodegradable packaging materials. Chitosan is one of the most abundant biopolymers after cellulose. Chitosan-based materials have been widely applied in various fields for their biological and physical properties of biocompatibility, biodegradability, antimicrobial ability, and easy film forming ability. Different chitosan-based films have been fabricated and applied in the field of food packaging. Most of the review papers related to chitosan-based films are focusing on antibacterial food packaging films. Along with the advances in the nanotechnology and polymer science, numerous strategies, for instance direct casting, coating, dipping, layer-by-layer assembly, and extrusion, have been employed to prepare chitosan-based films with multiple functionalities. The emerging food packaging applications of chitosan-based films as antibacterial films, barrie...

Chitosan based nanocomposite films and coatings: Emerging antimicrobial food packaging alternatives

Abstract: Background: Demand for healthy and safe food with minimal use of synthetic inputs (including synthetic preservatives) is increasing rapidly. Plastic polymers being hazardous to the environment, sig ...