ABSTRACT:The antibacterial activity of a series of soluble pyridinium-type polymers with different compositions against Escherichia coli (E. coli ) suspended in sterilized distilled water was investigated by a colony count method. The results show that the antibacterial activity of the soluble pyridinium-type polymers is characterized by their activity to kill bacterial cells and this activity can be enhanced as the content of the pyridinium group ( C q ) in the polymers increases. The species of the bacteria has a great influence upon the antibacterial activity of the soluble pyridinium-type polymers. The polymers possess a strong ability to kill Gram-positive and Gram-negative bacteria, and yeasts, excepting Bacillus subtilis, having gemmae and fungi. The toxicity of this kind of polymer has also been appraised. In the acute stimulation and allergy experiments, the red maculae, edema, and abnormal phenomena of an allergy on the skin of the tested animals were not observed. The acute toxicity experiment shows that the LD 50 of the polymer is 2330 mg/kg, implying that this kind of polymer has only very weak toxicity. This is significant for the application of soluble pyridinium-type polymers.

The copolymers of 4‐vinylpyridine (4VP), styrene (St) and divinylbenzene (DVB) with varied compositions, P(4VP‐St‐DVB), were synthesized by suspension polymerization using 2,2′‐azobisisobutyronitrile (AIBN) as an initiator. The insoluble (crosslinked) pyridinium‐type polymers in benzyl–pyridinium bromide form, which possess various macromolecular chain compositions, were prepared by the reaction of each P(4VP‐St‐DVB) with benzyl bromide (BzBr), respectively. By using different halohydrocarbon RX in the quaternization of P(4VP‐St‐DVB), the insoluble pyridinium‐type polymers with various pyridinium group structures were obtained. The structures of P(4VP‐St‐DVB) and its quaternized product Q‐P(4VP‐St‐DVB) were identified by FTIR. The 4VP content in each copolymer P(4VP‐St‐DVB) was measured by nonaqueous titration; and the pyridinium group content (Cq) in each Q‐P(4VP‐St‐DVB) sample was determined by means of the back titration manner in argentometry and/or the elemental analysis method, respectively. In addition, the particle structure and the surface morphology of the thus‐prepared polymer were observed using SEM. According to a series of experimental results, the preparation and characterization of insoluble pyridinium‐type polymers are analyzed and discussed. This work can prepare the ground for a study on the antibacterial activity of insoluble pyridinium‐type polymers. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 668–675, 2000

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SYNOPSJSCopolymerization of 4-vinylpyridine (4VP) with styrene (St) was performed in ethanol using 2,2'-azobisisobutyronitrile (AIBN) as an initiator, and then a random copolymer P(4VP-St) was obtained. A soluble pyridinium-type polymer containing N-benzyl-4-vinylpyridinium bromide [Q-P(4VP-St)], was prepared by quaternization of P(4VP-St) with benzyl bromide (BzBr). The structures of P(4VP-St) and its quaternized product Q-P(4VP-St) were identified by FTIR. The 4VP content in P(4VP-St) and the pyridinium group content (C,) in Q-P(4VP-St) were determined by nonaqueous titration and argentometry, respectively. The molecular weight of p(4VP-St) was characterized by intrinsic viscosity. In addition, the charge density u of the soluble pyridinium-type polymers was measured by colloid titration, and the mathematical relation between u and C, was established as follows: u = -0.090 + 0.942 C,. A preliminary investigation was made into the viscosity behavior and electroconductivity of the Q-P(4VP-St)/polar solvent system. 0 1996 John Wiley & Sons, Inc.aquatic environment?-12 The studies revealed their broad prospects for development and application in the fields of bioengineering, bioinstrumentation, and environmental protection. In this work, the preparation and characterization of soluble pyridiniumtype polymers are discussed. EXPERIMENTAL MaterialsComonomers 4-vinylpyridine (4VP) and styrene ( St) were purified by distillation under reduced pressure. 2,2'-Azobisisobutyronitrile (AIBN) was refined by recrystallization twice. Other chemicals and solvents were used without further purification. Preparation of SamplesBoth the synthesis and the quaternization of the copolymer P(4VP-St) of 4VP with St were carried out in a four-necked round-bottom flask equipped

ABSTRACT:In this article, the humidity sensors based on the vinylpyridine (VP)-butyl acrylate (BA)-styrene (St) copolymers are developed. The influencing factors of the copolymer's humidity sensing properties, such as the mol percentage of the fed monomers and the quaternization reagent ratio (namely, dibromobutane : butyl bromide ratio), are studied, and the long-term stability of the copolymers is investigated as well. The results show that as the content of BA increases and the content of St decreases, the copolymer's hysteresis and response time decreases, and with the increasing of the quaternization reagent ratio, the copolymer's hysteresis and response time decreases. Also, the sensors based on the copolymers show 2-3% RH reproducibility under various long-term test conditions. These results demonstrate an overall excellent performance in the reproducibility and long-term stability.