Polymerization of asymmetric polyfunctional monomers. III. Ionic polymerization of acrylic and methacrylic esters of 2-allylphenol

The polymerization of acrylic and methacrylic esters of 2-allyphenol with different anionic, cationic and coordination catalysts was studied. The polymerization occurs exclusively or predominantly through (meth)acrylic C?C double bonds in all the studied cases. With anionic catalysts the allylic groups are not polymerizable and the polymers have linear structure. Polymerization with catalysts based on dialkylaluminum chloride (alone or associated with some metal salts) yields soluble or partially crosslinked polymers, depending on the reaction conditions. The crosslinking is due to the participation of allylic groups in the polymerization reactions. Copolymers of acrylic and methacrylic esters of 2-allylphenol with styrene, acrylonitrile, methyl methacrylate, N-vinylcarbazole and 1,3-pentadiene were synthesized by copolymerization in the presence of anionic catalysts and of systems based on dialkylaluminum chloride.     

Metal-acetylacetonate chelate crosslinked gels

Polymers containing pendant acetylacetonate (acac) groups suitable for crosslinking through metal complex formation are described. Diene-based copolymers, polystyrene, and polydimethylsiloxane, each containing a measurable number of acac groups distributed along the chains, were synthesized. The polymers were studied both for the amount of acac ligand and for their crosslinking reactions with selected transition metals by ultraviolet (UV) second-derivative spectroscopy. The UV analyses of the polymer systems were compared with their monomer analogs, and the results confirm that the crosslinking chelation reactions of polymer compounds are similar to those of model compounds. Homogeneous chelate crosslinking conditions were developed by using transition-metal salts such as Cu(laurate)₂, Fe(laurate)₃, and Cr(laurate)₃ in solvents such as chloroform and benzene. Polymeric ligands containing 1–5% acac in solution at various concentrations were reacted to form both inter- and intramolecular crosslinkages. The kinetic stability of the chelate crosslinks has been studied by a unique ligand exchange–gel solubility relationship.     

Imidazole-containing chitosan derivative: a new synthetic approach and sorption properties

A novel method for the synthesis of a hetaryl-containing chelate amino polymer, namely, N-(4(5)-imidazolylmethyl)chitosan (IMC), with a degree of substitution up to 0.3 was proposed. The “synthesis in gel” approach involves direct substitution of the hydroxyl group in 4(5)-imidazolylmethanol. The structures of these polymers were confirmed by ¹H NMR data. For sorption studies, IMC samples were crosslinked with epichlorohydrin and diglycidyl ethers of ethylene glycol and diethylene glycol. The degrees of swelling and sorption properties of the polymers largely depend on the crosslinking agent and the degree of crosslinking. The sorption capacities of IMC for Au^III, Pt^IV, and Pd^II ions are higher than those of the nonmodified polymer. The extraction of noble metal ions from chloride solutions becomes more selective with increasing degree of crosslinking. The sorption capacity of IMC for Co^II and Ni^II ions is higher than those of chitosan and its known N-heterocyclic derivatives.     

Thermal degradation behaviour of some metal chelate polymer compounds with bis(bidentate) ligand by TG/DTG/DTA

Seven novel divalent transitional metal chelate polymers compounds (commonly known as chelate compounds or metal coordination complexes or polymer complexes) have been characterized by thermogravimetry (TG), differential thermal gravimetry (DTG) and differential thermal analysis (DTA) methods. Thermal decomposition behaviour of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) polymers with terphthaoyl-bis(p-methoxyphenylcarbamide) has been investigated by thermogravimetric analysis (TGA) at heating rate 10 °C min^?1 under nitrogen atmosphere. TG/DTA of chelate compounds were shown to be a stable compound against thermal decomposition which was measured on the basis of final decomposing temperature, but it is observed in some curves that decomposition takes place at low temperature due to the lattice water, which is always placed at outer coordination sphere of the central metal ion. The presence of both lattice and coordinated water were noteworthy investigated in Co(II), Ni(II) and Cu(II) chelate polymer compounds, whereas lattice water found in Zn(II), Cd(II) and Hg(II). However, Mn(II) showed only coordinated water. Thermal stabilities for release of lattice water, coordinated water and organic moiety that occur in sequential decomposition of chelate compounds are explained on the basis of ionic size effect and electronegativity. The processes of thermal degradation taking place in seven chelate polymers were studied comparatively by TG/DTG/DTA curves which indicating the difference in the thermal decomposition. Coats–Redfern integral method is used to determine the kinetic parameters for the successive steps in the decomposition sequence of TG curves. Scanning electron microscope images of some chelate polymers were shown in previous publication revealed that particle sizes of chelate polymers were found to be of nanomaterial level therefore, resulting chelate compounds might be called as nanomaterial.     

STUDY ON THERMAL DECOMPOSITION KINETICS OF URUSHIOL METAL CHELATE POLYMERS

The thermal decomposition kinetics of urushiol-Cu, urushiol-Nd and urushiol-Ti chelatepolymers has been studied by non-isothermal thermogravimetry. The results suggest that thethermal decomposition kinetics of three chelate polymers are all of first order. Their averageactivation energy values of the thermal decomposition calculated by Ozawa-(I) method are 110,79, 136. 98 and 163. 64 kJ mol~(-1) respectively, which increase linearly with the metal valence of themetal chelate polymers     

Unique thermal behavior of acrylic PSAs bearing long alkyl side groups and crosslinked by aluminum chelate

An acrylic pressure-sensitive adhesive (PSA), bearing octadecyl acrylate, methyl acrylate and acrylic acid groups, and crosslinked by aluminum acetylacetonate (AlACA), displayed behavior unique among acrylic PSAs in that its adhesion, which decreases with an increase in temperature, began to increase again from around 150 °C. In order to understand this behavior, the structure and thermal properties of the PSA were investigated in detail, along with another PSA crosslinked by a covalent crosslinking agent (Az). From thermal mechanical analysis, the PSA with ionic crosslinks (AlACA) showed three softening points at 20, 60, and 160 °C. In comparison, the PSA covalently crosslinked by Az only exhibited two softening points (at 20 and 60 °C). The softening point at 160 °C is clearly related to ionic chelate crosslinking. DSC measurements indicated that the softening point at 20 °C resulted from melting of the ordered octadecyl group, and the softening point at 60 °C was due to an increase in the mobility of the main chain. The temperature dependence of viscoelastic measurements revealed that the viscosity of the PSA crosslinked by AlACA increased at around 160 °C. From these results, we considered that the distinctive adhesion of the PSA crosslinked by AlACA could be due to ligand exchange at the aluminum crosslinking points, which are chelated by carboxy groups built in the main chain.     

Synthesis of polymers by use of divalent metal salts of monohydroxyethyl phthalate: Metal-containing isocyanurate-type crosslinked polyurethanes

Divalent metal salts (I) of monohydroxyethyl phthalate have catalytic activity for polymerization of isocyanate groups. The synthesis of novel metal-containing isocyanurate-type crosslinked polyurethanes were investigated by the crosslinking reaction of I in DMF with diisocyanates or urethane prepolymers, that is, diisocyanate adducts of polyethylene glycol. 2,4-Toluene diisocyanate and diphenylmethane diisocyanate were used as diisocyanates, and DMF was the solvent. The crosslinking reactions were followed by determining the gelation time. Gelation time decreased with increasing temperature. The Ca salt was more effective than the Mg salt in the crosslinking reaction. The yields of resulting metal-containing three-dimensional polymers decreased with increasing metal content in the feed. The Ca salt was more easily introduced into the network polymers than the Mg salt was. Decomposition temperatures decreased on introducing metals into the network polymers. Some physical properties of the metal-containing network polymers are also discussed.     

Organosilicon polymers based on polyvinylsilsesquioxane and sulfenyl chlorides of metal acetylacetonates

Addition of sulfenyl chlorides of metal acetylacetonates to poly(vinylsilsesquioxane) followed by addition of vinyltributylsilane has yielded polymers containing metal chelate fragments. The metal complex addition has been studied at varied ratio of the reagents; the highest reached conversion of vinyl groups is 60%.     

Effect of crosslinking on the photoinduced orientation of azo groups in thin polymer films

A series of amorphous copolymers containing disperse red 1 and crosslinkable acrylic groups were prepared. The crosslinked polymers were prepared in thin films by thermal polymerization of the acrylic groups in the copolymers. The orientation induced by irradiation with a linearly polarized laser was measured as birefringence at several temperatures, and the effect of crosslinking on the photoinduced orientation was investigated. Crosslinking enhanced the stability of the photoinduced birefringence. In particular, crosslinking helped to maintain the birefringence both at high temperatures and after the linearly polarized laser was turned off. The birefringence dynamics was analyzed with biexponential curve fitting. Crosslinking influenced not only the birefringence levels but also its rate of growth. The growth rate of the photoinduced birefringence decreased by crosslinking, whereas the relaxation was not significantly affected. Although crosslinking restrained the mobility of the azo chromophores, a certain fraction could orient or move randomly even in highly crosslinked polymer networks. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1686–1696, 2001     

Radical polymerization of metal-coordinated monomers with ligands of pyrrole-containing schiff bases

The copper complexes and the cobalt complex with the ligand of 3-(2-pyrrolylmethyl-enimino)propene-1 (PIP) or p-(2-pyrrolylmethylenimino)styrene (PIS) were synthesized and homopolymerizations and the copolymerization with styrene, acrylonitrile, methyl methacrylate and acrylic acid studied. In the polymerization of chelate monomers, inhibition of radical polymerization by the central metal ion was observed, but the chelate polymer could be obtained only if the initiator was present in higher concentrations in the feed. It is considered that the strength of inhibition depends on the electronic configuration of d-orbitals of the central metal ion. The initiation mechanism of the cupric chelate monomer may be reduction of the metal ion by the redox reaction with a primary radical via the intramolecular electron transfer through the π-conjugated system of the ligand prior to the propagation step. This mechanism was verified by studying the redox reaction of various copper complexes with DPPH. In the system of the copper complex containing PIS and acylic acid the alternating copolymer could be obtained at any mole fraction of monomer mixture in feed.     

Linear Conjugated Coordination Polymers Containing Eight-Coordinate Metal Centers

Two linear coordination polymers are reported in which conjugated organic ligands and nonrigid eight-coordinate metal centers are linked to form macromolecules with molecular weights of greater than 10⁴ Daltons. The tungsten(IV) chelate is an inert low-spin d² species with four oxygen and four nitrogen donors per metal with two bidentate blocking ligands and one bis-bidentate bridging ligand. The zirconium(IV) chelate is rendered inert through the use of a bis-quadridentate Schiff-base ligand. Future possibilities and potential uses are also discussed.     

Molecular design of supramolecular polymers with chelated units and their application as functional materials

This article summarizes the basic concepts and synthetic strategies leading to various types of supramolecular polymers with chelated units, including linear, branched, cross-linked, and heterometallic polymers. Particular attention is paid to such new synthetic approaches to supramolecular polymers as hierarchical and orthogonal self-assembly based on a combination of metal–ligand interaction with hydrogen bonds and host–guest interactions. Metallosupramolecular polyelectrolytes, supramolecular polymer gels, self-assembled metallosupramolecular monolayers, and supramolecular metal chelate dendrimers are analyzed. The stimuli-responsive, self-healing, and shape memory supramolecular polymers with chelated units are considered. The bibliography includes articles published over the past five years.     

Alkoxysilane Functional Acrylic Latexes: Influence of Copolymer Composition on Self-Curing Behavior and Film Properties

Reactive latexes based on acrylic polymers with trimethoxysilyl groups in the side chain were prepared by semi-continuous emulsion copolymerization. The properties of the latex film related to the polymer network structure and their evolution upon thermal curing were studied as a function of the content of the reactive comonomer, trimethoxysilylpropyl methacrylate (TSPMA), ranging between 8 and 25 wt-%. In particular, the sensitivity to both organic solvent (chloroform) and water and the thermomechanical properties were investigated by swelling experiments and dynamic-mechanical analysis (DMA). The results are interpreted in terms of a transition from uniform to microheterogeneous crosslinking regime, possibly as the result of formation of polyorganosilsesquioxane-like (POSS) crosslinking domains at higher TSPMA content.     

pH effects on the complexation, miscibility and radiation-induced crosslinking in poly(acrylic acid)-poly(vinyl alcohol) blends

The effect of pH on the complexation of poly(acrylic acid) with poly(vinyl alcohol) in aqueous solution, the miscibility of these polymers in the solid state and the possibility for crosslinking the blends using gamma radiation has been studied. It is demonstrated that the complexation ability of poly(vinyl alcohol) with respect to poly(acrylic acid) is relatively low in comparison with some other synthetic non-ionic polymers. The precipitation of interpolymer complexes was observed below the critical pH of complexation (pH(crit1)), which characterizes the transition between a compact hydrophobic polycomplex and an extended hydrophilic interpolymer associate. Films prepared by casting from aqueous solutions at different pH values exhibited a transition from miscibility to immiscibility at a certain critical pH, pH(crit2), above which hydrogen bonding is prevented. It is shown here that gamma radiation crosslinking of solid blends is efficient and only results in the formation of hydrogel films for blends prepared between pH(crit1) and pH(crit2). The yield of the gel fraction and the swelling properties of the films depended on the absorbed radiation dose and the polymer ratio. [Diagram: see text] SEM image of an equimolar PAA-PVA blend cast from a pH 4.6 solution.     

几种硅-硅链高聚物的合成和性质

采用具有不同取代基的二氯硅烷,在金属钠作用下共缩合的方法,合成了几种硅-硅链共聚物。这些共聚物分子量高,既能溶于一般的有机溶剂,也可在较低的温度下熔融,模压或浇铸成膜,或抽成纤维。在紫外光辐照下,高聚物的薄膜或纤维发生降解或交联反应。     

In situ formation of new crosslinking agents from acrylate derivatives and bisepoxides

The synthesis of several newly available diacrylate crosslinking agents derived from hydroxy functional acrylates and bisepoxides is described. These crosslinking agents are synthesized via the acid catalyzed addition of hydroxyl-containing acrylate monomers to bisepoxides derived from bisphenol-A and its hexafluoropropyl analog. These materials are generated in an excess of the acrylate monomer and the reaction mixtures are then converted directly to highly crosslinked materials. The alcohol functional monomers include hydroxyethyl methacrylate (HEMA) and the butyl and ethyl esters of (α-hydroxymethyl)acrylic acid. The latter are especially interesting for several reasons. First, they are readily available through the addition of the corresponding acrylate to formaldehyde. Second, these monomers react with the bisepoxides to give all-ether-linked connecting groups, in conrast to HEMA which yields a molecule with both ether and ester linkages between the two acrylate units. Third, the monomers are very different in solubility from HEMA and the polymers display very different chemical and physical properties. For example, while the crosslinked HEMA polymers are swellable in water, those of the (α-hydroxymethyl)acrylates are insoluble in water but swellable in organic solvents such as chloroform. All monomers, crosslinking agents, and crosslinked polymers were characterized by FT-IR, solution or solid state ¹³C-NMR spectroscopy, and thermal analysis.     

Radiation degradation susceptibility of vinyl polymers: Nitriles and anhydrides

The effect of γ irradiation on a series of vinyl polymers, which included polymethacrylonitrile, poly(α-chloroacrylonitrile), poly(dimethyl itaconate), poly(acrylic anhydride), and poly(methacrylic anhydride), was studied as part of a program to develop improved positive lithographic resists. Radiation-induced degradation was observed for polymethacrylonitrile, poly(α-chloroacrylonitrile), and poly(methacrylic anhydride). Molecular weight degradation as a function of dose was monitored by membrane osmometry or GPC techniques. For γ-irradiated poly(dimethyl itaconate) and poly(acrylic anhydride) crosslinking was found to predominate over chain scission. [G(s)–G(x)] values, calculated from molecular weight inverse versus dose curves, indicate that both nitrile polymers degraded more efficiently than a poly(methyl methacrylate) reference standard on the basis of M _n changes. The radiation behavior of the first three polymers confirms earlier findings than vinyl polymers with quaternary carbons predominantly degrade when subjected to ionizing radiation.     

Physicochemical Properties of Polyazomethine Polymers

Polyazomethine chelate polymers of 3d transition metal ions have been prepared and characterized in terms of elemental analysis, magnetic moment, electronic spectra, infrared spectra, and thermal and electrical properties. All the polymers exhibit 1:1 stoichiometry and are insoluble in common organic solvents.     

DSC研究高吸水树脂吸水性能与分子结构的关系

以丙烯酸(AA)、丙烯酰胺(AM)和2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为共聚单体合成了聚丙烯酸-丙烯酰胺-2-丙烯酰胺基-2-甲基丙磺酸(PAA-AM-AMPS)三元共聚物高吸水树脂.利用茶叶袋法测定了其最大吸水倍率,通过差示扫描量热仪(DSC)测定并比较了含水量为50%,75%和91%的各种水凝胶的自由水和结合水含量.结果表明在蒸馏水和生理盐水中高吸水树脂的最大吸水倍率分别为1900g/g和185g/g,共聚物的结合水含量随着AMPS和AA含量增加及AM含量的减少而增大;在0.9%生理盐水中,结合水含量随着AMPS和AM含量增加及AA含量的减少而增大,共聚物和均聚物高吸水树脂的最大吸水倍率呈现出与结合水含量相同的变化规律.     

SYNTHESES AND PROPERTIES OF SOME ORGANOSILANE POLYMERS

Some organosilane polymers with high molecular weights have been synthesized by cocondensztion of organosilicon dihalide monomers with sodium metal in toluene. These polymers are both soluble in common solvents and meltable at lower temperatures, and can be molded, cast into films or drawn into fibers. Exposure of the solid polymers to ultraviolet light leads to degradation or crosslinking.