Interfacial and Thermodynamic Properties of Formation of Water‐in‐Oil Microemulsions with Surfactants (SDS and CTAB) and Cosurfactants (n‐Alkanols C5–C9)

The interfacial and thermodynamic properties of water‐in‐oil microemulsion systems consisting of water, isopropyl myristate, n‐alkanol, and surfactant have been investigated using the method of dilution. The surfactants used were hexadecyl trimethylammonium bromide and sodium dodecylsulfate, and the cosurfactants were n‐alkanols with varying chain length from (C₅–C₉). The distribution of cosurfactant (n‐alkanol) between the interface of water and oil regions at the threshold level of stability as well as the energetics of the transfer of the cosurfactant from the oil to the interfacial region have been examined as a function of varying cosurfactant chain length (C₄–C₉) and temperature. The structural parameters (including dimension, population density and effective water pool radius) of the dispersed water droplets in the oil phase have also been evaluated and correlated with alkanol chain length.     

Polyimides derived from bis-N-hydroxyimides. II. Synthesis and properties of polyimide-esters

Polycondensation of bis-N-hydroxyimides, N,N′ dihydroxypyromellitic diimide, and N,N′ -dihydroxybenzophenonetetracarboxylic diimide with dicarboxylic acid chlorides was carried out in dimethylacetamide in the presence of triethylamine to produce novel polyimide-esters. The resulting polymers had inherent viscosities up to 0.27 dl/g. These polyimide-esters and model compounds exhibited high reactivity toward nucleophiles such as aniline and n-butylamine, which brought about rapid reductions in the viscosity of the polymers. These polymers were fairly resistant to organic solvents but soluble in m-cresol. Thermal stability oft he polyimide-esters was evaluated by thermogravimetry and their good heat-resistant properties were confirmed.     

Higher aliphatic polyaldehydes. IV. Transitions in poly(n-valeraldehyde), poly(n-hexaldehyde), poly(n-heptaldehyde), and poly(n-octaldehyde)

Crystalline polymers of n-valeraldehyde, n-hexaldehyde, n-heptaldehyde, and n-octaldehyde were prepared by anionic polymerization with lithium tertiary butoxide as the initiator at low temperatures. The polymers were end-capped with acetic anhydride, and their thermal stability was studied primarily by DTG. It was found that all polymers degrade rapidly above 150°C. All polymers show a dual melting-point behavior. The first melting region, which is associated with the melting of the side chain, is 80–85°C for poly(n-valeraldehyde); 87–90°C for poly(n-hexaldehyde); 78–101°C for poly(n-heptaldehyde); and 41–69°C for poly(n-octaldehyde). Annealing and quenching of the samples showed that this melting-point region consisted of several endotherm peaks whose intensity changed according to the thermal history of the sample. Although the samples are apparently highly crystalline, the side-chain crystallinity is apparently only in the 20% range.     

Polymers from 1,3-dipole addition reactions. The nitrilimine dipole from tetrazoles

Polymers containing pyrazole and triazole units in the polymer chain were obtained through the 1,3-dipolar addition reaction of bisnitrilimines generated from tetrazoles with diynes and dinitrile dipolarophiles. The reaction of 2,2′-diphenyl-5,5′-m- and p-phenyleneditetrazole with the dipolarophiles m- and p-diethynylbenzene, terephthalonitrile, tetrafluoroterephthalonitrile, perfluoroglutarylnitrile, and 4,4′-dicyanobiphenyl gave a series of thermally stable polymers of high molecular weight. The polypyrazoles were soluble in acid and in some cases in chlorobenzene or 1,2,4-trichlorobenzene and had intrinsic viscosities as high as 1.67, while the polytriazoles were soluble in 1,2,4-trichlorobenzene and chlorobenzene, but not in acid, and had viscosities ranging up to 0.40. The thermogravimetric analyses of the finely powdered polymers showed breaks near 500°C in air and nitrogen atmospheres.     

Polybenzopinacols. I. Photolytic coupling of aromatic diketones

Low molecular weight polybenzopinacols were obtained by the photolytic coupling of m- and p-dibenzoylbenzene and 4,4′-dibenzoyldiphenyl ether in isopropanol, tetrahydrofuran–isopropanol, benzene–isopropanol, and benzene–ethanol solutions. The polypinacols were soluble in common organic solvents such as tetrahydrofuran, ether, and benzene. The inherent viscosities ranged from 0.06 to 0.14. Average molecular weight (M?_n) data indicated that the polymers were mostly dimers and trimers.     

Polyaddition of bisketenimines. II. Synthesis of poly(N-acylamides) from bisketenimines and dicarboxylic acids

Poly(N-acylamides) were synthesized by polyaddition of bisketenimines with dicarboxylic acids. Yields and inherent viscosities of these polymers were low, presumably because of side reactions. The thermal stability and solubility of the polymers were studied.     

Polyimides derived from bismethylolimides. II. Polyamine-imides from bismethylolimides and diamines

Compounds in the N-methylolimide group reacted smoothly with amines in the presence of water to yield the corresponding condensation products. Polycondensations of bismethylolimides, N,N′-bismethylolpyromellitic diimide, and N,N′-bismethylolbenzophenonetetracarboxylic diimide, with amines such as aromatic diamines, piperazine, and n-butylamine, were carried out in DMAc that contained 1% water to produce linear polyamine-imides. The polyamine-imides assumed various colors, from very pale yellow to deep purple, and had inherent viscosities in the 0.07–0.37-dl/g range. Most of these polymers were soluble in polar solvents such as DMAc and DMSO. The thermal stability of the polymers was examined by thermogravimetric analysis; decomposition started at 210–350°C and weight residue at 500°C was 22–85% in air.     

Polymerizable siloxane precursors having in-chain perfluoroalkyl groups

The synthesis and polymerization of several silphenylene siloxane polymer precursors containing a perfluoroalkylsegment in the backbone was carried out. The molecular weight characteristics of polymers from 1,3-bis[p(-hydroxydimethylsilyl)phenyl]hexafluoropropane and 1,3-bis[p(-dimethylaminodimethylsilyl)phenyl]hexafluoropropane were studied as a function of polymerization conditions. Polymers containing the dodecafluorohexane chain segment were also prepared. Polymers having inherent viscosities of 0.55 to 0.9 were obtained. The polymers crosslinked at room temperature to thermoset elastomers which were characterized by improved thermal and oxidative stability over dimethylsilicones. Room temperature swelling of the experimental polymers hydrocarbon solvents was also much lower than that of dimethylsilicones. The polymers containing the (CF₂)₃ and (CF₂)₆ linkages had glass transition points of ?12°C and ?34°C, respectively.     

Studies on thermotropic liquid crystalline polyurethanes. II. Synthesis and properties of liquid crystalline polyurethane elastomers

Three series of novel thermotropic liquid crystalline polyurethane elastomers (TLCPUEs) were studied. Hard segments were formed by using hexamethylene diisocyanate (HDI) reacted with a mesogenic unit, benzene-1,4-di(4-iminophenoxy-n-hexanol), which also acted as a chain extender. Three diols: 1,10-decanediol,poly(oxytetramethylene) glycol (PTMEG) M _n = 1000 and PTMEG M _n = 2000 were used as the soft segments. The effects of soft segments of polyurethanes on the liquid crystalline behavior were studied. Higher molecular weight TLCPUEs were obtained by adding 30?50 mol % of mesogenic segments to diisocyanates. In contrast to a conventional chain extender such as 1,2-ethylene glycol or 1,4-butyl glycol, the synthesized polyurethane elastomers exhibited a mesophase transition by using a mesogenic unit as the chain extender. Mesophase was found for all synthesized LC polyurethanes except of polymers H2-A-12 and H2-A-7. The structures and the thermal properties of all synthesized TLCPUEs were studied by using FTIR spectroscopy, wide-angle x-ray diffraction (WAXD) and DSC measurements, a polarizing microscope equipped with a heating stage, dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA). Mechanical properties were also examined by using a tensilemeter. © 1995 John Wiley & Sons, Inc.     

Intrinsic viscosities of four homopolymers and one copolymer in nonpolar solvents. I. Effect of correlations of molecular orientations

Intrinsic viscosities [η] of four homopolymers, polyisobutylene (PIB), polypentene-1 (PP-1), polypentenamer (PPmer), and polydimethylsiloxane (PDMS), and of an ethylene-propylene copolymer containing 81% ethylene (81% E) have been measured at 25°C in seven linear alkanes ranging from n-C₆ to n-C₁₆ and three highly branched alkanes, 2,2,4-trimethylpentane, 2,2,4,6,6-pentamethylheptane, and 2,2,4,4,6,8,8-heptamethylnonane. Correlation of molecular orientations (CMO) in the polymers was investigated. The difference Δ[η] = [η](lin) ? [η](br) is used as a test of CMO with the supporting assumption that CMO lowers the free energy and the destruction of CMO raises it. The positive value of Δ[η], which varies from 20% to 40% for PPmer and 81% E, is indicative of orientational order in these two polymers. The negative value of Δ[η] for PDMS results from the disordering of linear alkanes by the nonordered PDMS. δ[η] is near zero for PP-1 and small for PIB implying that these two polymers are indifferent to solvent molecular shape. The variation of [η] with alkane chain length of the linear alkanes gives additional information about size and solvent quality. The dependence is small for ordered polymers due to the short range of CMO. [η] diminishes rapidly with n for PDMS probably because of the increased difference of cohesive energy between polymer and solvent. The dependence is small for PIB but very large for PP-1. The much better quality of small-molecule solvents for PP-1 may be an indication of a helicoidal conformation of this polymer in solution.     

Poly[bis(phosphinatoalanyl)phosphonates]

A series of coordination polymers, poly[bis(phosphinatoalanyl)phosphonates], [X(Y)AlOP(R)(O)OAl(Y′)(X′)]_n, were synthesized in which the terminal alanyl substituents (X,Y,X,′Y′) consisted of phosphinato (OPRR′O) or fluoro (F) moieties. The properties of the polymers were primarily dependent upon the type of terminal substituent and the hydrocarbon moieties (R,R′) on phosphorus. Polymers with four phosphinato moieties gave molecular weights M?_n to 120000 with intrinsic viscosities [η] from 1.5 to 18; the corresponding solids were partially crystalline, melted before decomposition, and were film-forming when larger phosphorus substituents were incorporated. Sequential replacement of the phosphinato moieties with fluorine resulted in molecular weights below 10000 and low viscosities. The properties of the polymers are examined, and the roles of substituents on probable structures are discussed.     

Aminimides. XII. Synthesis,homo- and copolymerization studies of trialkylamine N-acryloyl or N-methacryloyl glycinimides and β-aminopropanimides

Some representative examples of a new family of aminimide monomers, i.e., trialkylamine N-acryloyl or N-methacryloyl glycinimides and β-aminopropanimides have been prepared and studied. These are the first examples of a possible large family of primary aminimide monomers. With radical initiators, the acryloyl and monosubstituted methacryloyl monomers readily homopolymerize. The disubstituted methacryloyl aminimides do not homopolymerize under the same conditions. All of the new monomers copolymerize with styrene, methyl methacrylate, and n-butyl acrylate. The various polymers were characterized by IR, DTA, TGA, GPC and inherent viscosities. When heated (160°C) the polymers liberate amine and crosslink in the presence of active hydrogen moieties to give resins with carbamate, urea, allophonate, etc., residues. When no active hydrogens are available during heating, polymers can be prepared with pendent primary isocyanate groups. This preliminary work shows these monomers to be highly useful for preparing a wide variety of reactive copolymers.     

Two reaction routes for the preparation of aromatic polyoxadiazoles and polytriazoles: Syntheses and properties

Two reaction routes for the preparation of aromatic poly-1,3,4-oxadiazoles and poly-1,2,4-triazoles are studied and their influence on the physical properties, i.e., inherent viscosity, glass transition, degradation temperature, and film integrity of the final products are discussed. Aromatic poly-1,3,4-oxadiazoles are prepared by means of a polycondensation reaction of terephthaloyl chloride and isophthalic dihydrazide yielding a precursor polymer, poly(p, m-phenylene) hydrazide, which is converted into the corresponding poly-1,3,4-oxadiazole by means of a cyclodehydration reaction. Poly-1,3,4-oxadiazoles are also prepared by means of a polycondensation reaction between terephthalic and isophthalic acid and hydrazine yielding poly-1,3,4-oxadiazoles with higher inherent viscosities. Flexible poly-1,3,4-oxadiazole films are obtained only if the inherent viscosities of the polymers used are higher than 2.7 dL/g. The thermal stability is found to increase with increasing content of p-phenylene groups in the polymer backbone. Aromatic poly-1,2,4-triazoles are prepared using polyhydrazides with alternating para- and meta-phenylene groups and poly-1,3,4-oxadiazoles with a random incorporation of para- and meta-phenylene groups in the main chain as precursor polymers. The glass transition temperatures are found to increase with increasing content of p-phenylene groups in the main chain of these polymers. Cold crystallization is observed only for the alternating polymer. © 1994 John Wiley & Sons, Inc.     

Dielectric relaxations and electrical conductivities of poly(alkyl methacrylates) under high pressure

Dielectric properties of four methacrylate polymers (methyl, ethyl, n-butyl and n-octyl) were studied in the frequency range 0.0001 cps–300 kcps at temperatures above and below the glass transition temperature and at various pressures up to 2500 atm. At temperatures well above T_g a single relaxation peak (α′ peak) was observed in the case of the higher n-alkyl methacrylates. However, this peak was split into two peaks, α and β, with decrease in temperature or increase in pressure. The molecular motions corresponding to the α and the β relaxation processes are the micro-Brownian motions of amorphous main chains and of flexible side chains, respectively. From the temperature and the pressure dependence of the average dielectric relaxation time of these polymers the single relaxation process (the α′ process) was attributed to the micro-Brownian motion of the main chain coupled with that of the side chain. The effects of temperature and pressure on the d.c. conductivity of these polymers were also studied.     

Polymerization of surface-active monomers. VIII. Tacticity of polymers prepared by radical polymerization of quaternary salts of dimethylaminoethyl methacrylate in micellar and isotropic media

The effect of monomer micellization on the polymerization was studied from the standpoint of stereochemistry in the polymerization. Quaternary salts (C_nBr) of dimethylaminoethyl methacrylate with n-alkyl bromide having N (=4, 8 and 12) carbon atoms were polymerized with radical initiators in isotropic and anisotropic media and the resulting polymers were converted to poly (methyl methacrylate) (PMMA) to determine their tacticity. Tacticities of poly (C₁₂Br)s were little affected by initiators and solvents used for their preparations. There was little dependence of the tacticities on alkyl chain length (N) for poly (C_nBr)s prepared in water and dimethylformamide (DMF). Most of polymers produced here conformed to Bernoullian propagation statistics and a definite difference was not found in the tacticities between the polymers prepared in isotropic and anisotropic media. From the results obtained here it was deduced that the micellar aggregation has little influence upon the stereochemistry in the polymerization of the quaternary monomers. © 1994 John Wiley & Sons, Inc.     

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.     

Synthesis,characterization, and properties of linear poly(ether sulfone)s with dendritic terminal groups

Hybrid linear‐dendritic ABA polymers, where A and B are dendritic and linear polymers, respectively, were synthesized in a single step via step‐growth polymerization of 4,4′‐difluorodiphenylsulfone and bisphenol A using arylether ketone dendrons of first and second generations (G1‐OH and G2‐OH) as monofunctional end‐cappers. These G1 and G2‐terminated poly(ether sulfone)s (G1‐PESs and G2‐PESs) were characterized by ¹H NMR, SEC, DSC, TGA, melt rheology, and tensile tests. The comparison of the glass transition temperatures (T_gs) of these polymers with those of t‐butylphenoxy‐terminated polysulfones reveal that the G1‐ and G2‐PESs have lower T_gs at all molecular weights investigated. However, a plot of T_g versus 1/M_n shows that the difference between the three series becomes negligible at infinite molecular weight and agrees to the chain end free volume theory. The melt viscosities of G1‐PES and G2‐PES with high molecular weights do not show a Newtonian region and, in the high frequency region, their viscosities are lower than that of the control while the stress–strain properties are comparable to those of the control, suggesting that it is possible to reduce the high shear melt viscosity of a PES without affecting the stress–strain properties by introducing bulky dendritic terminal groups. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 958–969, 2008     

Polymerization by Phase-Transfer Catalysis. Part 20. Synthesis of Polycarbonates and Polythiocarbonates with an Ester Group in the Side Chain

Abstract

Poly(ester-carbonate)s and poly(ester-thiocarbonate)s were synthesized from diphenols containing an ester group in the side chain and phosgene or thiophosgene under phase-transfer conditions. The polymers were characterized by elemental analysis and IR spectroscopy, and the molecular weights were estimated by inherent viscosity measurements. The influence of the nature of the catalysts and the structure of the diphenols on the yields and inherent viscosities was studied. We found that the catalysts were effective for all monomers, although the inherent viscosity values were low due to the insolubility of the polymers in the reaction media. Without catalyst, the polymers were not obtained.     

Head-to-head vinyl polymers. III. Preparation and characterization of head-to-head poly(acrylic acid) and its esters

Head-to-head (h-h) poly(acrylic acid) (PAA) and some h-h poly(alkyl acrylates) (PRA) with methyl, ethyl, n-propyl, n-butyl, isobutyl and 2-ethylhexyl substituents were prepared by hydrolysis or esterifications of the alternating copolymer of ethylene with maleic anhydride. In general, these esterification reactions became increasingly difficult as the carbon chain in the alcohols lengthened or branched. The softening, glass transition, and degradation temperatures of the h-h polymers obtained were somewhat higher than those of the corresponding head-to-tail (h-t) polymers. The main degradation products of both h-h and h-t PRA were identified by pyrolytic gas chromatography as the alcohol and monomer. In addition, the relative ratios of the amounts of alcohol to monomer were larger for h-h than for the corresponding h-t polymers.     

Synthesis of mesoporous hydrophobic silica microspheres through a modified sol–emulsion–gel process

Mesoporous silica microspheres were synthesised through a sol–emulsion–gel process using Span 80 as the surfactant in silica sol/n-hexane water in oil emulsion system. Surface modification of the microspheres was done with trimethylchlorosilane to obtain hydrophobic silica microspheres. Various parameters related to the synthesis of microspheres, including concentration of surfactant and viscosities of sol were studied. The hydrophobicity (wettability), thermal stability, porosity, and morphological features were also investigated.