Protecting biodegradable coatings releasing antimicrobial agents

This article describes the synthesis and in vitro analysis of poly(ester anhydride) antimicrobial protection coatings. Poly(ester anhydride)s composed of ricinoleic acid, sebacic acid, terephthalic acid, and isophthalic acid were used in this study. The polymers were compatible with various fillers commonly used in paint preparation. The in vitro experiments showed that the polymers are able to release diuron, an antimicrobial agent, for months. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Fabrication and optical characterization of poly(2,5‐di‐n‐butoxyphenylene) nanofibril arrays

Anodic aluminum oxide (AAO) membrane can be used as template for the synthesized nanostructures. In this article, we have prepared the AAO membrane by using electrooxidation of aluminum substrate in phosphoric acid, and fabricated poly(2,5‐di‐n‐butoxyphenylene) (BuO–PPP) nanofibril arrays by oxidative coupling polymerization of 1,4‐di‐n‐butoxybenzene (DBB) within the pores of the AAO template membrane. The detailed molecular structure of the polymer nanofibrils was characterized by using infrared and ¹H nuclear magnetic resonance spectra, and estimated to consist of almost equal fractions of 1,4‐ and 1,3‐ linkages. We have used transmission electron microscopy, scanning electron microscopy, and atom force microscopy to confirm the morphologies and images of the AAO template membrane and the fabricated nanometer scale of BuO–PPP nanofibril arrays. The experimental results demonstrated that the pores of the AAO membrane were regular and uniform, and parallel each other, and the BuO–PPP chains in the narrowest template‐synthesized nanofibrils were oriented parallel to the porous axes of the AAO membrane and perpendicular to the surface of the aluminum substrate. The polymer chain orientation was partially responsible for the enhanced conductivity. The ultraviolet absorption spectrum of the BuO–PPP nanofibril arrays shown that the polymer contains a better extended π‐conjugation system along poly‐(p‐phenylene) backbone, which resulted in longer wavelength shift of the absorption band, the absorption maxima were located at 258 nm (E₁ absorption band) and 332 nm (E₂ absorption band), respectively. Photoluminescence spectrum of the BuO–PPP nanofibril arrays exhibited a blue emission. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 425–430, 2004     

Synthesis of nitropyridine‐based π‐conjugated polymers and their chemical properties

π‐Conjugated poly(3‐nitropyridine‐2,5‐diyl) ( PPy‐3‐NO₂ ), poly(3,3′‐dinitro‐2,2′‐bipyridine‐5,5′‐diyl) ( PBpy‐3,3′‐diNO₂ ), and a poly(arylene ethynylene) type polymer consisting of a 3,3′‐dinitro‐2,2′‐bipyridine unit ( PAE‐1 ) were synthesized by Cu‐promoted Ullmann coupling reaction and Pd‐catalyzed coupling reaction. PPy‐3‐NO₂ and PAE‐1 were soluble in organic solvents such as DMSO, DMF, and chloroform, and gel permeation chromatography analysis showed a number average molecular weight (M_n) of 9,300 and 12,300, respectively. PPy‐3‐NO₂ gave intrinsic viscosity, [η], of 0.53 dL g^?1 in DMF. PBpy‐3,3′‐diNO₂ had somewhat lower solubility. The polymers exhibited a UV–vis peak at about 430 nm. PPy‐NO₂ received electrochemical reduction at ?1.5 V versus Ag⁺/Ag in acetonitrile, and gave an electrochemical redox cycle in a range from 0 to ?1.1 V versus Ag⁺/Ag in an aqueous solution. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1763–1767, 2006     

Hide tanning with modified natural tannins

Tannin from “Acacia Mearnsii” usually called Mimosa, is largely employed in vegetal tanning of hide even if the quality of the leather is poorer than that obtained using chromium as tanning agents. However, taking into account the natural resources of this product and its reduced environmental impact, mimosa tannin has been modified to obtain leather having improved properties. Tannin was modified using formaldehyde, urea, a sulfonic acid and a sulfiting agent: The new products show a higher molecular weight than mimosa tannin but maintain a good solubility in water. Modified tannins were characterized through physicochemical and technological tests and evaluated as tanning agents. The properties of tanned leathers obtained using the new tannin products and mimosa were compared. Some of the polymers containing phenolsulfonic acid are good tannin agents, especially those with a suitable molecular weight. The technological and sensorial properties of the leather obtained using modified tannins (distension and strength of grain, tensile strength, elongation, and tear load) are better than those obtained using mimosa when an appropriate ratio of the reagents were employed. At the same time the feeling of the tanned leather was improved and the final products show fullness, elasticity, fluency, reactivity, and a thin and fine grain. Some of the tannins modified with naphtalensulfonic acid show poor tanning properties but good penetration in the leather suggesting their use as auxiliary sintans in the pretanning process. A simple procedure to prepare these modified tanning agents in the course of the tannin extraction is suggested. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of cross‐linkable poly(phthalazinone ether ketone)s

A novel class of crosslinkable poly(phthalazinone ether ketone)s with relative high molecular‐weight and good solubility were successfully synthesized by the copolymerization of bisphthalazinone containing monomer, 3,3′‐diallyl‐4,4′‐dihydroxybiphenyl and 4,4′‐di‐ fluorobenzophenone. The synthesized polymers with inherent viscosities in the range of 0.42 to 0.75 dL/g can form flexible and transparent membranes by casting from their solution. The crosslinking reaction of these polymers can be carried out by thermally curing of the virgin polymers in or without the presence of crosslinking agent. The experimental results demonstrated that the crosslinking reaction also occurred to some extent during the polymerization. The crosslinked polymers exhibited equivalent glass transition temperature (T_g) at lower crosslinking density, and showed higher T_g than virgin polymers at higher crosslinking density. The crosslinked high‐temperature polymer can be used as the base material for high temperature adhesive, coating, enamel material, and composite matrices. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Separation of water–isopropyl alcohol mixtures with novel hybrid composite membranes

New‐fangled hybrid composite membranes were prepared by the incorporation of 5, 10, and 15 mass % NaY–zeolite particles into blend membranes of carboxymethyl cellulose (CMC)‐g‐acrylamide/sodium alginate (NaAlg) and crosslinked with glutaraldehyde. The pervaporation (PV) separation performance of the hybrid composite membranes was explored for the dehydration of isopropyl alcohol from their aqueous solutions at 30°C. The effect of NaY–zeolite in these blend membranes was investigated in PV dehydration. From the experimental results, we found that NaY particles could be intercalated in the aqueous polymer solution. The obtained results show that both the flux and selectivity increased simultaneously with increasing zeolite content in the membrane. This was explained on the basis of an enhancement of the hydrophilicity, selective adsorption, and molecular sieving action by the creation of pores in the membrane matrix. The membranes were characterized by differential scanning calorimetry, scanning electron microscopy, and Fourier transform infrared spectroscopy. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012     

Synthesis and photoluminescent properties of poly(aryl ether)s containing alternate emitting and electron‐transporting moieties

A new diphenylbutadiene‐containing bisphenol was successfully synthesized from benzylideneaniline and 4‐propenylanisole via an anil synthetic method. A series of copoly(arylene ether)s consisting of an alternate isolated blue chromophore (diphenylbutadiene) and an electron‐transporting moiety (1,3,4‐oxadiazole) was synthesized and characterized. High molecular weight copoly(arylene ether)s with an inherent viscosity of >0.5 dL/g were prepared by the nucleophilic displacement reaction of oxadiazole‐activated bis‐fluorocompounds with bisphenols. Introduction of ether linkages into the copolymers led to an enhanced solubility in organic solvents such as N,N‐dimethylacetamide (DMAc) and N‐methyl‐2‐pyrrolidinone (NMP). The resulting copolymers can be cast into tough and transparent films. The copolymers were amorphous in structure with high glass transition temperatures ranging from 182.29 to 194.50°C. They also exhibited good thermal stability with the maximum decomposition temperatures higher than 500°C in nitrogen. The absorption peaks of these copolymers in thin films varied from 375 to 391 nm, while the photoluminescent peaks varied from 410 to 433 nm. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1645–1651, 2003     

Synthesis and chemical properties of dielectric polyphenylenes with nitro group

Polyphenylenes consisting of nitrophenylene and didodecyloxy‐p‐phenylene units have been synthesized by Pd‐catalyzed organometallic polycondensation. The polymers showed good solubility and had number–average molecular weights (M_n) of 13,000–37,000. Their spin‐coated films showed fairly high dielectric constants (ε) of 3.75–6.36. The polymers were electrochemically active with electrochemical reduction peaks in the range of ?1.72 to ?1.99 V versus Ag⁺/Ag in an acetonitrile solution of [NEt₄]BF₄ (0.10M). The polymer composed of 2,3′‐dinitrobiphenyl and didodecyloxy‐p‐phenylene units showed thermotropic liquid crystalline phase at about 240°C. Cast films of the polymer had a birefringent phase at room temperature, suggesting self‐assembly of the polymer in the solid. XRD studies revealed that the polymers assumed an ordered structure assisted by aggregation of the long alkoxy side chains in the solid. The polymer main chain in the cast film is considered to be aligned parallel with respect to the surface of substrates. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

含酞菁络合物的聚芳醚砜的合成及光电性能

以聚芳醚砜为主链,金属酞菁作为接枝基团,分别合成了含有酞菁镁,酞菁锰,酞菁钴的聚芳醚砜。该类聚合物具有很好的热稳定性,其5%的分解温度均在360℃以上,在极性溶剂中展示出良好的溶解性能。对其光电性能进行表征,溶液的紫外-可见吸收均在300 nm～400 nm及600 nm～800 nm出现很强的光谱吸收,且吸收光谱的峰...     

Side‐chain free aromatic polyimides containing anthracene units via Diels‐Alder precursors

Side‐chain free aromatic polyimides are expected to possess extraordinary mechanical properties and stability because of strong primary and secondary bonding forces. However, their low solubility makes it difficult to characterize, process, and obtain high molecular weight polymers. We have prepared highly stable thin films of side‐chain free aromatic polyimides from soluble Diels–Alder (DA) precursors. Heating the films of the precursors above 215°C induced retro‐DA reaction, which converted the precursors to the fully aromatic polyimides. The solid‐state retro‐DA reactions were monitored by attenuated total reflection Fourier transformed infrared (ATR‐FTIR) and UV‐Vis spectrometry. A critical issue for utilizing precursor chemistry in polymer synthesis is that it may result in porous and/or deformed materials. In this work, profilometry and atomic force microscope (AFM) were applied to study the surface and volume change. Our results showed that smooth and pin‐hole free films were obtained after the thermal treatment, while the volume decreased with a percentage close to the weight loss caused by the retro‐DA reaction. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009