Styrene and polystyrene microemulsions. I. Solubility in the W/O system

The solubility of styrene, its oligomers, and different molecular weight polymers was determined in W/O microemulsions stabilized by sodium dodecyl sulfate and pentanol. The results showed a complex pattern due to the interactions with pentanol, surfactant, and associated structures.     

Highly stable olefin-Cu(I) coordination oligomers and polymers

Highly stable Cu(I)-olefin coordination oligomers and polymers have been successfully prepared and applied to construct metal-organic frameworks (MOFs) with interesting physical and chemical functions in recent years. In this review, we present the olefin-Cu(I) coordination oligomers and polymers and their novel physical properties. From structure to functions, particular emphasis is placed on the coordination and organometallic chemistry of olefin-Cu(I) coordination oligomers and polymers, their structures and potential applications as solids possessing unusual physical functional properties such as electrochemical, chiral separation, fluorescent sensing and ferroelectricity.     

Modeling solubilization of oil mixtures in anionic microemulsions II. Mixtures of polar and non-polar oils

Polar/amphiphilic oils, called lipophilic linkers, are sometimes added to oil-water-ionic surfactant microemulsions in order to increase the solubilization of hydrophobic oils. The solubilization increase has been well documented for a number of systems. However, mathematical models to calculate the solubilization increase have been proposed only for optimum microemulsions (i.e., middle phase microemulsions solubilizing equal volumes of oil and water). In this paper we propose a model, which predicts solubilization enhancement for non-optimum microemulsion systems as well. The model is an extension of the net-average curvature model of microemulsion. The net-average curvature model is combined with a surface activity model to account for the increased palisade layer solubilization due to the presence of the polar/amphiphilic oil component. New non-linear mixing rules are also incorporated to account for the optimum salinity and the characteristic length variation of the anionic surfactant microemulsion as a function of the lipophilic linker concentration. The model predicts the effect of the lipophilic linker and the electrolyte concentration on the oil solubilization in accordance with the experimental results.     

Dielectric absorption in hydrocarbon polymers with non-polar additives

Polypropylene films containing various non-polar additives including CCl₄, tetramethylsilane and CS₂ (99.9 or 99.8%) exhibit weak dielectric absorption at the temperatures where molecular tumbling motions are expected on the relevant timescale. The absorption possibly corresponds to rotational jumps of up to 90° between inequivalent orientations of the additive molecules as has been suggested for ammonium in alums.     

Solubility of freons in polar and non-polar liquids at 298.15 K

The cavity formation energy (CFE) is the free energy invested in rearrangement of the solvent molecules when a solute is inserted into a solvent, which is very important to the solubility studies. The CFE of liquid solvents; n-heptane, n-octane, cyclohexane, tetrachloromethane, benzene and water at 298.15 K has been determined. The solubility (in terms of Henry’s law constant), Gibb’s free energy of solution and ΔG_s^*, the thermodynamical quantities for the solvation process defined by Ben-Naim and Marcus of fluorine containing gases; freon-11, freon-12, freon-13, freon-14, freon-21, freon-c-318 and sulpherhexafluoride (SF₆) in above liquid solvents at 298.15 K also been calculated with this cavity formation energy. It yields good agreement with experimental results. The calculation shows importance of CFE in determining the solution properties.     

Functional polymers. XIX. Biuret oligomers and polymers of biologically active primary aliphatic amines

Biuret oligomers and polymers from primary aliphatic amines and aromatic or aliphatic diisocyanates have been synthesized. To demonstrate the feasibility of the synthesis of polybiurets, aliphatic primary amines with n-propyl, n-hexyl, n-octyl, and n-dodecyl groups have been incorporated. For the synthesis of biuret oligomers of biologically active primary aliphatic amines [8-(4-amino-1-methylbutylamino)-6-methoxyquinoline] (primaquine) and adamantanamine were selected. Primaquine was also incorporated into polyepichlorohydrin by nucleophilic substitution of the chlorine of the chloromethyl group by the primary aliphatic amino group of primaquine. The structure of the biuret polymers was established by elemental analysis, and by infrared ¹H- and ¹³C-NMR spectroscopic characterization. Several attempts to use primaquine as a diamine for the formation of condensation polymers, including reaction of primaquine with sebacoyl chloride (to form polyamides), or with diisocyanates (to form polyureas) were unsuccessful.     

Low band-gap oligomers and polymers

The relationship between electronic structure and chemical stability is discussed for three different classes of low band-gap oligomers and polymers. In oligo- and poly[n]acenes as well as in poly-(arylenemethide)s, the low band-gap character is connected with a high chemical reactivity due to an energetically favored rearomatization of olefinic or quinonoid substructures, respectively. For double-stranded oligo- and poly(rylene)s, the stability is dramatically increased. Therefore, rylenes appear especially promising in the field of low band-gap materials.     

Phenylethynyl-terminated imide oligomers and polymers therefrom

Two new phenylethynyl endcapping compounds, 3- and 4-amino-4′-phenylethynylbenzophenone, were synthesized and used to terminate imide oligomers from 3,4′-oxydianiline and 4,4′-oxydiphthalic anhydride at a calculated molecular weight of 9000 g/mol and from 3,4′-oxydianiline (0.85 mol), 1,3-bis (3-aminophenoxy) benzene (0.15 mol), and 3,3′,4,4′-biphenyltetracarboxylic dianhydride at a calculated molecular weight of 5000 g/mol. Glass transition temperatures for the cured oligomers were ～ 249°C for the former and 272°C for the latter. Films cured at 350°C for 1 h were tough and flexible and provided high tensile properties. The uncured oligomers were readily compression molded to provide tough, solve nt-resistant moldings. © 1994 John Wiley & Sons, Inc.     

Solubility and diffusion of water in acetal polymers

The rate of water sorption at 25°C. has been determined for a number of polyacetal films differing in structure, density, and orientation induced by extrusion. The equilibrium water uptake was found to be a linear function of density only; no other effect of structure or orientation was detectable. The extrapolated density for zero sorption was 1.51 g./cc., not far from the theoretical crystalline density. The diffusivity of water in unoriented films rose with decreasing density; for linear copolymer, the trend was parallel to that of the area under the dynamic mechanical loss peak associated with long-range chain motions in the disordered regions (β-transition). Less pronounced effects of molecular weight and long chain branching on diffusivity were also noted. Films crystallized while an extruded melt was still oriented showed considerable increases in water diffusivity, but no significant changes in the apparent activation energies of permeation (about 6.6 kcal./mole) or diffusion (about 11.5 kcal./mole). On annealing these films, the diffusivity remained almost constant while the sorption coefficient and retraction on remelting decreased.     

Diffusion in glassy polymers. I

Synopsis The diffusion of six solvents in three crosslinked, glassy epoxy polymers is studied. Case II swelling and Fickian sorption are observed as two simple limiting cases. The mechanism of diffusion changes from one limit to another as the nature of the solvent or the crosslink density of the polymer is altered. With mixed solvents, properly chosen, a superposition of Fickian diffusion and case II swelling is observed.     

s-Triazines. I. Linear,sulfur bridged-s-triazine oligomers

A number of new thioether and disulfide oligomers of s-triazine have been prepared and identified. The reactions between 2,4-diphenyl-s-triazine-6-thiol and chloro substituted-s-triazines are described. A suggested mechanism for the formation of 2,2′-thiobis-(4,6-diphenyl-s-triazine) from 2,4-diphenyl-s-triazine-6-thiol is discussed.     

Optically and redox-active ferroceneacetylene polymers and oligomers

The palladium-catalyzed Sonogashira reaction can be used to build optically active, oligomeric 1,2,3-substituted ferrocenes up to the tetramer, as well as polymers, by sequential coupling of optically active (ee > 98 %), planar chiral iodoferroceneacetylenes and ferroceneacetylenes. (SFC)-1-Iodoferrocene-2-carbaldehyde (1) was reduced to the alcohol and methylated to give the corresponding methyl ether, which was Sonogashira-coupled with HC(triple bond)CSiEt3, resulting in (RFc)-1-(C(triple bond)CSiEt3)-2-methoxymethylferrocene (4) (79%, three steps). Orthometalation with tBuLi followed by quenching with 1,2-diodoethane gave (RFc)-1-(C(triple bond)CSiEt3)-2-methoxymethyl-3-iodoferrocene (5). Deprotection of the acetylene with nBu4NF resulted in (RFc)-1-ethynyl-2-methoxymethyl-3-iodoferrocene (6), which was Sonogashira-coupled with itself to produce an optically active polymer. Deprotection of 4 with nBu4NF and Sonogashira coupling of the product with 5 resulted in the dinuclear ferrocene 9. Deprotection of 9 and coupling with 5, followed by deprotection of the resulting acetylene 11, gave the trinuclear ferrocene 12. Another such sequence involving 11 and 5 produced a tetranuclear ferrocene 13. To study the electronic communication in such oligomers in more detail, two symmetrical, closely interrelated, trinuclear ferrocenes 18 and 19 were synthesized. The redox potentials of all the ferrocenes and the ferroceneacetylene polymer were determined by cyclic and square-wave voltammetry. All the metallocenes were investigated by UV/Vis spectroscopy. A linear relationship was found between lambdamax and l/n (n=number of ferrocene units in the oligomer). The polymer displayed two redox waves in the cyclic voltammogram, at 0.65 and 0.795 V. The corresponding mixed-valence oligoferrocene cations were synthesized from four ferroceneacetylenes, and their metal-metal charge transfer bands were examined by UV/Vis-NIR. The resonance exchange integrals Had, calculated on the basis of spectral information from the metal - metal charge transfer (MMCT) bands, were between 290 and 552 cm-1.     

Stereoregular and conformationally regular oligomers and polymers

Configurationally and conformationally regular polymers can now be synthesized based on sterically restrictive considerations. Trihaloacetaldehyde polymerization provided a fertile field for the investigation of the factors for such polymer formations. The convenient ceiling temperature of trihaloacetaldehyde polymerizations allowed the study of the genesis of these polymerizations. Oligomers were prepared by alkoxide initiation, followed by the establishment of the oligomer alkoxide equilibrium and end-capping. Stereoregularity and conformational regularity were observed in trichloroacetaldehyde (chloral) and tribromoacetaldehyde (bromal) polymerizations. This result was confirmed by solid state magic angle spinning NMR investigations of polychloral, of polybromal as well as of a copolymer of chloral and bromal. Solid state NMR techniques allowed also to investigate copolymers of chloral and aromatic isocyanates. Quantification of the solid state investigation suggests the possibility of a molecular weight estimation of chloral and other insoluble trihaloacetaldehyde polymers by end-group analysis.     

Development of synthetic double helical polymers and oligomers

There is growing interest in the design and synthesis of artificial helical polymers and oligomers, in connection with biological importance as well as development of novel chiral materials. Since the discovery of the helical structure of isotactic polypropylene, a significant advancement has been achieved for synthetic polymers and oligomers with a single helical conformation for about half a century. In contrast, the chemistry of double helical counterparts is still premature. This short review highlights the recent advances in the synthesis, structures, and functions of double helical polymers and oligomers, featuring an important role of supramolecular chemistry in the design and synthesis of double helices. Although the artificial double helices reported to date are still limited in number, recent advancement of supramolecular chemistry provides plenty of structural motifs for new designs. Therefore, artificial double helices hold great promise as a new class of compounds. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5195–5207, 2009     

Sequence-regulated oligomers and polymers by living cationic polymerization. III. Synthesis and reactions of sequence-regulated oligomers with a polymerizable group

New sequence-regulated macromonomers ( 3 ) with a vinyl ether terminal were prepared by the HI/ZnI₂-mediated living cationic polymerization of vinyl ethers: CH₃? CH(OR¹)? CH₂CH(OR²)? C(COOEt)₂CH₂CH₂OCH?CH₂ ( 3a : R¹ = nBu, R² = CH₂CH₂OCOPh; 3b : R¹ = iOct, R² = CH₂CH₂Cl). The synthesis consisted of three consecutive steps: (i) quantitative addition of hydrogen iodide to the first vinyl ether into an adduct [CH₃? CH(OR¹)? l]; (ii) propagation of a second vinyl ether from the adduct in the presence of zinc iodide; and (iii) quenching the resulting AB-type heterodimeric living intermediate with a carbanion [^θC(COOEt)₂CH₂CH₂OCH?CH₂] carrying a vinyl ether group. The HI/ZnI₂-initiated living cationic polymerization of 3a and 3b yielded narrowly distributed polymers $\left( {\overline {DP}} _{_n } \sim 10 \right)$ consisting of a poly(vinyl ether) backbone and sequence-regulated oligomer branches. The terminal vinyl ether function of 3 was also utilized to prepare pentamers and hexamers with controlled sequence of functional vinyl ethers by selective dimerization and chain extension reactions with HI/ZnI₂. © 1993 John Wiley & Sons, Inc.     

Phthalocyanine polymers. II. Synthesis and characterization of some metal phthalocyanine sheet oligomers

Metal phthalocyanine oligomers that possess peripheral carboxylic acid groups were prepared by the reaction of pyromellitic dianhydride, a metal salt, urea, and a catalyst. These materials have blue to purple colors with a metallic luster and are soluble in sulfuric acid, dimethylsulfoxide, dimethylformamide, and dimethylacetamide. Their thermal stability is high in an anaerobic atmosphere with char yields of 80–85% at 800°C. Elemental, spectral, and titrimetric analyses and thermal studies were carried out to characterize them.     

Thermotropic liquid crystalline polymers. I. Cholesterol-containing polymers and copolymers

An approach to the creation of thermotropic cholesterol-containing liquid crystalline polymers by the chemical binding of cholesterol molecules with side chains of comblike polymers is presented. This type of structure permits a decrease in the steric hindrances provided by the backbone chains for the purpose of realizing the liquid crystalline state. A number of new cholesteric esters of poly(N-methacryloyl-ω-aminocarbonic acid)s (PChMAA-n) with different side-chain lengths (n = 2–11) as well as a series of copolymers of ChMA-n with n-alkylacrylates and n-alkylmethacrylates have been synthesized. The experimental evidence of liquid crystalline structure formation in these polymers in glass, viscoelastic, and fluid states is discussed. Molecular and supermolecular structures of cholesterol-containing comblike polymers have been studied and the model of macromolecular packing in the liquid crystalline state is proposed. It is shown that the existence of a layered order of side methylene groups together with ordering of cholesterol groups is necessary to the production of the liquid crystalline state in these polymers.     

Silazane oligomers and polymers with phenylene spacing groups

Heating N,N′-diphenyltetramethylcyclodisilazane with phenylenediamines in the melt at temperatures over 200°C was found to yield oligomers composed of linear and cyclic disilazane units interlinked by phenylene groups. Increasing the temperature of the reaction of meta- and particularly para-phenylenediamine over 300°C promotes formation of crosslinked, infusible, and insoluble polymeric material. The succeeding steps of growth of the polymer molecules, which include cyclodisilazane ring cleavage, transaminations, and recyclizations, have been studied by elemental and spectroscopic analyses of the intermediate low molecular and oligomeric species in the distillable and nonvolatile products of the reactions.     

Macrocycles, catenanes, oligomers and polymers in gold chemistry

A critical review is given of the chemistry of macrocycles, catenanes, oligomers and polymers in gold chemistry. Because gold centres are typically labile towards ligand substitution, there may be an easy equilibrium between the cyclic and linear oligomeric or polymeric forms and the preferred products of self-assembly are usually determined by thermodynamic control. The ways in which the self-assembly of complex structures from simple building blocks by dynamic coordination chemistry can be manipulated by ligand design or by the use of secondary bonding forces is emphasized (39 references).