Bacterial growth on food is a main factor in the reduction of food quality, leading to short-term food shelf life. Development of antibacterial packaging can inhibit the bacterial growth and extend food shelf life. Silver loaded zeolite was used as the antibacterial agent in this work. Three zeolites (different Si/Al ratio) such as zeolite A, zeolite Y, and zeolite Socony Mobil-5 (ZSM-5) incorporating with the same silver content were prepared. The characterization was carried out by energy dispersive X-ray spectroscopy, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, nitrogen adsorption, and color analysis. Antibacterial activity of the three silver zeolites was tested against Escherichia coli and Staphylococcus aureus. Silver loaded zeolite ZSM-5 showed better bacterial inhibition than silver incorporated zeolite A and Y. For composite film preparation, silver loaded zeolite ZSM-5/poly(butylene succinate) composite films were prepared by varying silver loaded zeolite ZSM-5 concentrations and characterized by different techniques (mechanical test, scanning electron microscopy, and color analysis). Poly(butylene succinate) composite films filled with silver loaded zeolite ZSM-5 showed 99.9% of bacterial reduction within 24 h, indicating the effective antibacterial activity. From the silver migration results, the silver release from poly(butylene succinate) films was less than the limitation of European Food Safety Authority regulation, indicating the safety for food packaging applications.
(Arylimido)niobium(V)–alkylidene complexes, Nb(CHSiMe3)(NAr)[OC(CF3)3](PMe3)2 (Ar = C6H5 (4), 2,6-F2C6H3, C6F5 (6)), Nb(CHSiMe3)(N-2,6-Cl2C6H3)(OC6F5)(PMe3)2 (7), and Nb(CHSiMe3)(N-2,6-F2C6H3)(OC6Cl5)(PMe3)2, have been prepared and identified. The pentafluorophenylimido
analogue 6 and 7 showed superior catalytic
activities for the ring-opening metathesis polymerization (ROMP) of
norbornene (TOF = 56.1, 53.7 s–1, respectively,
at 25 °C) and the activities increased at 50 °C (TOF ≥
352 s–1). The prepared alkylidenes catalyzed the
ROMP of cis-cyclooctene (COE), and the activity increased
at high temperature (up to 80 °C). The Z-specific
ROMP of COE has been demonstrated especially by the phenylimido analogue 4 at 80 °C, affording polymers possessing olefinic double
bonds with exclusive cis selectivity (99%).
This work was focused on the effects of filler concentration on the antibacterial activity and biodegradable behavior of poly (butylene succinate) (PBS) composite films containing silver exchanged zeolite ZSM-5 (SZSM-5). The composite films were prepared by chill roll cast film extrusion, by varying the silver zeolite content from 0.5 to 4 %wt. The silver content in zeolite was examined by energy dispersive X-ray spectroscopy (EDX). The morphology and crystal structure of silver zeolite were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) technique, respectively. The incorporation of silver did not influence the zeolite morphology and its crystal structure. The antibacterial action of composite films was investigated against gram-negative Escherichia coli and gram-positive Staphylococcus aureus. The results revealed that the PBS composite films containing SZSM-5 showed 99.9% of bacterial reduction. The optimal SZSM-5 content in PBS composite films was 0.5%wt because it was the lowest concentration that showed high efficiency of antibacterial behavior. In case of biodegradable ability, PBS composite films incorporated with 0.5%wt of SZSM-5 exhibited the degradation after three-month of soil burial test, although they exhibited slower rate than neat PBS films. The SEM micrographs of the films after soil burial test displayed the cavity on film surface, indicating the biodegradable properties of the films. PBS composite films incorporated with 0.5%wt of SZSM-5 showed the potential to be used as the food packaging.
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