bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemiluminescence of hydrocarbon polymers
Authors: Jirackova L. Audouin , Verdu J.
Published: April 2003

The thermal oxidation of some hydrecarbon polymers differing by their degree of branching was studied simultaneously by chemiluminescence and infrared spectrophotometry. In the case of isotactic polypropylene, measurements were made at various temperatures ranging from 140 to 180°C. The other polymers—ethylene–propylene copolymer, low and high density polyethylene—were studied only at 160°C. In all cases, the induction times of chemiluminescence coincide with those of carbonyl growth. The previously proposed mechanisms of light emission are not consistent with the kinetic data or with the structure effects on luminescence, which seems directly related with the presence of tertiary hydrogens. A hypothetical mechanism based on the β scission of tertiary alkoxyls is proposed.
Molecular factors affecting solubility in rigid‐rod polyamides
Authors: Gaudiana R. A. , Minns R. A. , Rogers H. G. , Sinta R. , Taylor L. D. , Kalyanaraman P. , McGowan C.
Published: April 2003

The solubility of a series of para‐linked, substituted phenyl, biphenyl, terphenyl, and quaterphenyl polyamides is reported. Most of these polymers are soluble in amide solvents without lithium chloride, and several are soluble in ethers and/or ketones. The results indicate that solubility in this class of polymers is affected by the position, polarizability and size of the substituents, enantiomeric purity, and the number of non‐coplanar biphenyl rings per repeat unit.
Study of the ceric ion behavior on the initiation of butyl acrylate polymerization onto amylose
Authors: Vázquez M. B. , Goñi I. , Gurruchaga M. , Valero M. , Guzmán G. M.
Published: April 2003

A study of the Ce(IV) ion consumption during graft polymerization of butyl acrylate with amylose was carried out. The Ce(IV) consumed was ca. 80% and the ratio of Ce(IV) to anhydroglucose units was 1/15. Poly(butyl acrylate) (PBA) chains were isolated from the grafted copolymer by the perchloric acid hydrolysis method. The molecular distribution was obtained by gel permeation chromatography (GPC). The number‐average molecular weight (Mn) of the grafted chains was 276,000 and the weight‐average molecular weight (Mw) was 1,320,000. The total number of grafted chains (mmol) ranged from 0.4410−3 to 8.710−3 (amylose from 0.08 g to 1.23 g). Frequency of grafting ranged from 1042 to 704.
Water‐soluble copolymers. XXV. Ion‐binding studies of N‐substituted acrylamide copolymers using potentiometric and spectroscopic methods
Authors: McCormick C. L. , Elliott D. L.
Published: April 2003

Spectroscopic and potentiometric methods have been used to study the ionic properties of several N‐substituted acrylamide copolymers that display unusual ion‐binding character. The ionic groups and the amide groups (both on the same repeating unit and on adjacent acrylamide units) in the copolymers are found to chelate calcium ions. The stabilizing effect of this amide chelation is found to be dependent on copolymer composition. A model is proposed to explain the unusual binding behavior of the acrylamide polymers. This involves the formation of an intramonomer chelate or one with neighboring acrylamide units that prevent precipitation of the polymers.
New thermo‐crosslinking reactions of polymers containing pendant epoxide groups with various polyfunctional active esters
Authors: Nishikubo Tadatomi , Saita Seiji , Fujii Takato
Published: April 2003

New thermo‐crosslinking reactions of poly(glycidyl methacrylate), copolymers of glycidyl methacrylate with methyl methacrylate, styrene or ethyl acrlate with various active esters such as di[S‐(2‐benzothiazoly)] thioadipate (BTAD), di(S‐phenyl) thioadipate (PTAD), di(4‐nitrophenyl) adipate (NPAD), diphenyl adipate (PAD), and di(S‐phenyl) thioisophthalate (PTIP), and other polyfunctional esters were carried out in the film state using various catalysts such as quarternary ammonium or phosphonium salts, tert amines, or the crown ether 18‐crown‐6 = potassium salts system. Addition reactions of pendant epoxide groups in the polymer with the active esters such as NPAD and PTAD proceeded selectively to give gel compounds without other side reactions. The rates of reaction with the thioesters such as BTAD and PTAD were relatively faster than those with the phenyl esters such as PAD and NPAD at 70°C. The rates of reactions with the esters having flexible segments such as PTAD were also faster than those with the esters having rigid skeletons such as PTIP. Furthermore, it was found that the rate of reaction was affected strongly by reaction temperature, catalyst concentration, length of alkyl chain in the catalyst, kind of counterion of quarternary ammonium salts as a catalyst, content of pendant epoxide groups in the polymer, and kind of copolymer unit in the polymer, respectively.
Esterification reactions on syndiotactic poly(2‐methallyl alcohol). II. Esterification with protected (L)‐aspartic and (L)‐glutamic acids
Authors: Frey W. , Klesper E.
Published: April 2003

The esterification of syndiotactic poly(2‐methallyl alcohol) by Nα‐ and Oω‐ protected aspartic and glutamic acids by the DCC/HOBT method is described. Depending on the extent of conversion, either homopolymers or copolymers are obtained. Both homo‐ and copolymers are characterized by 1H‐ and 13C‐NMR. A second route to the homopolymers has been followed, whereby the poly(2‐methallyl alcohol) is first esterified by Nα‐protected aspartic or glutamic acid anhydrides and, in a second step, the resulting free carboxyl group on the side chain is esterified by alcohols which are the same as the alcohol moiety of the Oω‐protecting groups. Because the homopolymers were identical to those of the first route, the formation of α‐esters with the acid anhydrides is indicated.
Spectroscopic study of the interaction of poly(ε‐N‐methacryloyl‐L‐lysine) with copper(II)
Authors: Castellano Azélio , Lekchiri Abdenbi , Morcellet Joëlle , Morcellet Michel
Published: April 2003

The complexes formed between copper(II) and a polymeric ligand derived from L‐lysine, poly(ε‐N‐methacryloyl‐L‐lysine) have been investigated by electronic absorption, circular dichroïsm, and EPR spectroscopy. The model molecule, ε‐N‐isobutyroyl‐L‐lysine was also studied with the purpose to distinguish between the effects due to the polymeric nature of the ligand and its intrinsic complexing properties. All experiment results are consistent with the existence of two CuL and CuL2 complexes for both model and polymer Cu systems with no deprotonation of the amide group. The two complexes involve only the carboxyl and amino groups. With the polymer, the CuL2 complex is the main species, even at low pH and low [ligand]/[metal] ratio. This is attributed to the high local concentration of ligand in the vicinity of the polymer chain. With the model molecule, on the contrary, the distribution of the two complexes is strongly dependent on the pH and the [ligand]/[metal] ratio.
Synthesis and electrical conductivity of polymers containing trans‐1,2‐bis(9‐carbazolyl)cyclobutane units
Authors: Subramaniam Prema , Sasakawa Tomoyoshi , Ikeda Tomiki , Tazuke Shigeo , Srinivasan Mahalingam
Published: April 2003

Novel poly‐Schiff bases (PSB's) that contain trans‐1,2‐bis(9‐carbazolyl)cyclobutane(DCZB) units were synthesized by the direct polycondensation of trans‐1,2‐bis(3‐formyl‐9‐carbazolyl)cyclobutane with aromatic diamines in n‐amyl alcohol at 160°C. Complexation of these PSB's and of poly(vinyl DCZB) (PVDCZB) with iodine produced cation‐radical salts which resulted form the transfer of an electron from DCZB moieties to iodine. All the undoped polymers were insulators having electrical conductivity of the order of 10−10–10−12 S cm−1 depending on the structure of polymers. By doping with iodine, the electrical conductivity increased by several orders of magnitude and reached a value of 10−3 S cm−1 in the case of PVDCZB and 10−5–10−6 S cm−1 in the case of PSB's. The electrical conductivity of doped PSB's increased with decreasing diamine length. PVDCZB having the same iodine content per carbazole unit as poly(9‐vinyl‐carbazole) (PVK) has a greater electrical conductivity than PVK.
Novel method for preparation of photocrosslinkable poly(vinyl alcohol)
Authors: Ichimura Kunihiro , Komatsu Toshio
Published: April 2003

A convenient procedure to prepare photosensitive poly(vinyl alcohol) by acetalization with 1‐methyl‐4‐(p‐formylstyryl)pyridinium methosulfate in heterogeneous condition is described. The reaction of fully saponified poly(vinyl alcohol) was carried out in suspension in acidic aqueous solution, while partially saponified poly(vinyl alcohol) was acetalized in acidic aqueous organic solvent. The photosensitive poly(vinyl alcohol) thus prepared was purified by filtration and successive washing out with methanol. The effect of the preparative condition on the electronic absorption spectra of the styrylpyridinium group attached to poly(vinyl alcohol) is discussed.
Polymerization ofpara‐xylylene derivatives (parylene polymerization). IV. Effects of the sublimation rate of di‐p‐xylylene on the morphology and crystallinity of parylene N deposited at different temperatures
Authors: Surendran G. , Gazicki M. , James W. J. , Yasuda H.
Published: April 2003

The effect of the sublimation rate of di‐p‐xylylene on the crystallinity and morphology of Parylene N deposited on stainless steel was studied as a function of substrate temperature. For a given rate of dimer sublimation, the deposition rate increases with decreasing substrate temperature. Increasing the sublimation rate of the dimer increases the deposition rate 10‐fold, decreases the crystallinity, and shifts the appearance of the hexagonal β structure towards higher substrate temperature for samples synthesized from room temperature (RT) to −60°C. Solution annealing resulting from solvent extraction, and isothermal annealing, increase the crystallinity of the polymers and result in structures containing both α and β polymorphs. The surface topology, as revealed by scanning electron microscopy (SEM), for polymers synthesized from RT to −40°C shows a globular structure, whereas low temperature samples exhibit a rod‐type morphology. For higher sublimation rates of the dimer, SEM micrographs show that oligomeric species start appearing on the polymer films after a period of 4–5 days. Solvent extraction removes the oligomeric crystals, and GPC analysis of the resulting extract indicates that most of the oligomers range in molecular weight from 100 to 900. The cross‐sectional morphology for fractured low temperature samples, however, reveals different morphologies as polymerization proceeds. It is postulated that in the temperature range −50 to −78°C, both surface condensation and surface adsorption of monomer occurs, leading to different morphologies and lower crystallinity. The polymer synthesized at liquid nitrogen temperature shows the presence of voids along with different morphologies. X‐ray diffractograms of polymers synthesized at liquid nitrogen reveal a considerable amount of amorphous phase in the films. Hence, it is inferred that, although the liquid nitrogen polymerization is a solid state polymerization of the crystalline monomer, it does not lead to 100% crystalline material, and the reasons for this are discussed.
ESR study of the molecular dynamic of peroxyradicals in the post‐irradiation oxidation of isotactic polypropylene
Authors: Faucitano A. , Buttafava A. , Martinotti F. , Bortolus P. , Comincioli V.
Published: April 2003

By adopting the modified Bloch equations, the analysis of the motion of macroperoxyradicals during the post‐irradiation oxidation of isotactic polypropylene at room temperature has been performed. Rotations about the chain axis and cubic jumps are the motion of prominent importance in the early stages of reaction involving mostly radicals trapped at defects or in amorphous phase; on the other hand rotations about the CO bonds at decreasing rates are dominant in the latter stages. Clear evidence of the progressive immobilization of peroxyradicals, which may be reckoned with monomolecular termination mechanism and of the trapping of peroxyradicals in the crystalline phase, have been obtained.
Effects of organometallic cocatalysts on the polymerization of disubstituted acetylenes by TaCl5 and NbCl5
Authors: Niki Akihiro , Masuda Toshio , Higashimura Toshinobu
Published: April 2003

The effects of organometallic cocatalysts on the polymerization of disubstituted acetylenes were investigated. Diphenylacetylene did not polymerize with TaCl5 alone, while it produced a polymer quantitatively in the presence of appropriate cocatalysts (Me4Sn, Et3SiH, etc.). The poly(diphenylacetylene) formed was an insoluble yellow solid. 1‐Phenyl‐1‐alkynes (1‐Phenyl‐1‐butyne and ‐1‐octyne) polymerized with TaCl5 and NbCl5 alone to yield polymers whose weight‐average molecular weights (Mw's) were ca. 5 × 105. Use of cocatalysts (nBu4Sn etc.) to the polymerization of these monomers accelerated the reaction, and increased the polymer molecular weights up to ca. 1.5 × 106. The poly(1‐phenyl‐1‐alkynes) were soluble white solids. Internal octynes (2‐, 3‐, and 4‐octynes) gave mixtures of a polymer and cyclotrimers with TaCl5 alone. In contrast, cyclotrimers formed virtually selectively by addition of cocatalysts. Thus, various effects of organometallic cocatalysts were observed depending on the kind of monomer.
Photocrosslinkable polymers having p‐phenylenediacrylate group in the side chain: Argon laser photoresist
Authors: Ichimura Kunihiro , Nishio Yoshihiro
Published: April 2003

Preparative methods and photosensitivity characteristics of polymers bearing the p‐phenylene‐diacrylate (PDA) group are described. Condensation of a copolymer of methyl methacrylate and glycidyl methacrylate with p‐phenylenediacrylic acid monoester gave highly photosensitive polymers. An alternative method to introduce PDA group is the substitution of chloromethyl‐styrene polymer with p‐phenylenediacrylic acid monoester monoalkali salt. The latter method was found to be more favorable for preparing soluble photosensitive polymers. The polymers thus prepared showed high sensitivity to light of 488 nm from an Argon laser when sensitizers are used, and the photocrosslinking quantum efficiency was 0.44. Preliminary results on holographic recording with this polymer is also mentioned.
Separation and characterization of cyclic sulfides formed in the polycondensation of dibromoalkanes with aromatic dithiols
Authors: Montaudo G. , Scamporrino E. , Puglisi C. , Vitalini D.
Published: April 2003

MS and GPC analyses are used to identify the cyclic oligomers formed in the polycondensation reactions of aromatic dithiols and dibromoalkanes leading to aromatic‐aliphatic polysulfides. A correlation exists between the two sets of data obtained by these techniques. Mass spectra of the cyclic oligomers formed in the polymerization reactions are reported.
Degradation of vinylidene chloride/phenylacetylene (VDC/PA) copolymers. Effect of internal unsaturation on poly(vinylidene chloride) stability
Authors: Howell B. A.
Published: April 2003

The thermal degradation of vinylidene chloride/phenylacetylene copolymers containing small but varying amounts of phenylacetylene has been examined in both the solid phase and in bibenzyl solution. Incorporation of phenylacetylene into the poly(vinylidene chloride) structure greatly facilitates degradative dehydrochlorination. Indeed, the presence of phenylacetylene promotes the formation of polyene segments during the polymerization process so that all the copolymers, even at very low phenylacetylene loading, are tan in color. The decreased stability of polymers containing interal unsaturation arises from an increased rate of initiation for degradative dehydrochlorination. The propagation rate is largely unaffected by the level of unsaturation initially present in the polymer. The ratio of hydrogen chloride to stilbene formed for degradation of these copolymers in bibenzyl solution is approximately 35:1. This suggests that the chlorine atom of the initially‐formed radical pair preferentially abstracts an adjacent hydrogen atom rather than interacting with solvent, i.e., the chain‐carrying radical pair does not dissociate appreciably as the unzipping dehydrochlorination occurs. Thus random double bonds introduced in a variety of ways may be identified as principal defect sites responsible for the initiation of the degradative dehydrochlorination of poly(vinylidene chloride). Species which promote the degradation of poly(vinylidene chloride) probably do so by facilitating the introduction of random double bonds into the structure.
Degradation of vinylidene chloride/methyl acrylate/phenylacetylene (VDC/MA/PA) terpolymers. Effect of internal unsaturation on the stability of Saran copolymers
Authors: Howell B. A. , Delassus Phillip T.
Published: April 2003

The thermal degradation of vinylidene chloride/methyl acrylate/phenylacetylene (VDC/MA/PA) terpolymers containing a constant 9 wt % methyl acrylate and small but varying amounts of phenylacetylene has been examined in the solid phase and in bibenzyl solution. Thermally promoted degradative dehydrochlorination, largely uncomplicated by methyl chloride formation, readily occurs at temperatures approaching 200°C. Incorporation of phenylacetylene into the polymer structure greatly facilitates degradative dehydrochlorination. Indeed, the presence of phenylacetylene induces the formation of polyene segments during the polymerization so that all the terpolymers, even at very low phenylacetylene loading, are tan in color. The decreased stability of polymers containing internal unsaturation arises from an increased rate of initiation for the degradation reaction. The propagation rate is largely unaffected by the level of unsaturation initially present in the polymer. Thus random double bonds have been identified as the principal defect sites responsible for the facile degradation of Saran copolymers. Species which promote the degradation of Saran polymers probably do so by facilitating the introduction of double bonds into the structure. The ratio of hydrogen chloride to stilbene formed for degradation of the terpolymers in bibenzyl solution is ca. 35:1. This is strongly reminiscent of PVDC degradation and suggests that for degradation of either the homopolymer or Saran copolymers the chain‐carrying allylic radical pair does not dissociate to any appreciable extent as dehydrochlorination occurs.
Ethylene–chlorotrifluoroethylene copolymers. I. Synthesis and evaluation of compositions resistant to thermal stress cracking
Authors: Reimschuessel H. K. , Rahl F. J.
Published: April 2003

Copolymerization of ethylene, chlorotrifluoroethylene, and small amounts (less than 5 mol %) of a perfluoroalkylethylene yields terpolymers in which the concentration ratio of the ethylenederived units to the units derived from the fluorine‐containing monomers is unity, indicating that the perfluoroalkylethylenes are incorporated at the expense of chlorotrifluoroethylene. The resulting polymer compositions are characterized by improved resistance to thermal stress cracking.
Effects of ammonia/ammonium thiocyanate on cotton fabric
Authors: Bober Hope L. , Cuculo John A. , Tucker Paul A.
Published: April 2003

The effect of ammonia/ammonium thiocyanate (NH3/NH4SCN) treatment of the swelling behavior, structural changes, and physical properties of cotton sheeting was compared with that of sodium hydroxide and liquid ammonia mercerization. Increased percent shrinkage, accessibility to a large dye molecule, dyestuff absorption, swelling with water, and water imbibition showed that NH3/NH4SCN had improved the accessibility of the cotton fabric. X‐ray diffractograms showed the characteristic Cellulose I crystal lattice. X‐ray diffraction and infrared absorption spectroscopy indicated that the crystallite size was unchanged and the swelling from the NH3/NH4SCN treatment occurred in the amorphous regions of the cellulose since the observed crystal structure was unchanged. Moisture regain determinations and barium hydroxide absorption suggested that some recrystallization of the cellulose may have occurred from the NH3/NH4SCN treatment. Fibers treated with NH3/NH4SCN showed a cross sectional shape similar to that of the origianl fibers but with reduced lumen area.
Ethylene polymerization over organochromium catalysts: A comparison between closed and open pentadienyl ligands
Authors: Freeman Jeffrey W. , Wilson David R. , Ernst Richard D. , Smith Paul D. , Klendworth Douglas D. , McDaniel Max P.
Published: April 2003

Divalent organochromium compounds, Cr(Lig)2, often become active catalysts for the polymerization of ethylene when deposited onto an oxide carrier such as silica or aluminophosphate. Hydroxyl groups are thought to react, releasing one ligand and binding the chromium to the surface. The behavior of the catalyst is then governed by the remaining ligand and the type of carrier. In this study two types of ligands were investigated: cyclopentadienyl and its open ring analog dimethylpentadienyl. This small difference in the type of ligand produces a fundamental difference in the polymerization mechanism. For comparison the mixed ligand chromocene, with one open and one closed ligand, was also synthesized and tested for polymerization.
Polymerization of para‐xylylene derivatives. V. Effects of the sublimation rate of di‐p‐xylylene on the crystallinity of parylene C deposited at different temperatures
Authors: Surendran G. , Gazicki M. , James W. J. , Yasuda H.
Published: April 2003

Poly(chloro‐p‐xylylene) was synthesized in a manner similar to poly(p‐xylylene) using Gorham's method at various cryogenic temperatures. The effect of the sublimation rate of dimer on the kinetics of deposition, crystallinity, and crystalline structure was studied. Increasing the sublimation rate of the dimer increases the deposition rate similar to that of poly(p‐xylylene). However, an increase in crystallinity, in contrast to Parylene N, is observed, although, in general, Parylene C has lower crystallinity relative to Parylene N. No polymorphism is observed either by decreasing the deposition temperature or by increasing the sublimation rate of the dimer. Solution annealing and isothermal annealing both bring about crystallization without any structural transformation. Solution annealing removes the oligomers and dimers, but no crystalline oligomers are ever detected under the scanning electron microscope (SEM). The surface topology of films synthesized from ambient temperature to −40°C is very similar to Parylene N. At lower temperatures, in the region −50 to −60°C, a rod‐type morphology is observed similar to Parylene N. The surface topology of samples synthesized at −196°C is totally different from that of Parylene N. All low temperature synthesized samples are amorphous.
Grafting onto poly(vinyl alcohol). II. Graft copolymerization of methyl acrylate and vinyl acetate and their binary mixture using γ‐rays as initiator
Authors: Misra B. N. , Mehta I. K. , Kanthwal M. , Panjloo S.
Published: April 2003

Methyl acrylate (MA), vinyl acetate (VAc) and their binary mixture (MA + VAc) have been graft copolymerized onto poly(vinyl alcohol) using γ‐rays as initiator by mutual radiation method in aqueous medium. The optimum conditions for affording maximum grafting have been evaluated. The percentage of grafting has been determined as a function of total dose, concentrations of poly(vinyl alcohol), MA, VAc, and their binary mixture. Rate of grafting (Rp) and induction period (Ip) have been determined as a function of total initial mixed monomer concentration and concentration of poly(vinyl alcohol). The graft copolymer has been characterized by thermogravimetric method. The effect of donor monomer (vinyl acetate) on percent grafting of acceptor monomer (methyl acrylate) has been explained.
Polyurethane anionomers. I. Structure properties of polyurethane anionomers
Authors: Al‐Salah H. A. , Frisch K. C. , Xiao H. X. , McLean J. A.
Published: April 2003

The influence of mono and divalent nontransition and transition metals on the glass transition and mechanical properties of polyurethane anionomers have been investigated. NCO‐terminated prepolymer prepared from 4,4′‐methylene‐bis(phenyl isocyanate) (MDI) and poly(caprolactone) glycol (PCL) was chain extended with dimethylolpropionic acid (DMPA), and the anionomers obtained by neutralization of the prepolymer. The glass transition temperatures of polyurethane anionomers have been studied as a function of the counterion. From simple electrostatic considerations, it is shown that a linear relationship exists between the glass transition temperature and ionic potential (ϕ) for these particular materials. The relation is; Tg = Aϕ + B. The mechanical properties are greatly affected by the type of the counterion, and in some cases, such as monovalent and nontransition metals, the mechanical properties of the anionomers improved by increasing the ionic potential. On the other hand, transition metals containing anionomers exhibited good mechanical properties but no relationship was observed between the mechanical properties and the ionic potential. The extent of water absorption of PU anionomers follows the same relative trends as the tensile strengths of the transition metals with filled and partially filled d‐orbitals.
New synthetic route to alternating copoly(aromatic ester–aliphatic amide)s
Authors: Lu C. X. , Yang Yang
Published: April 2003

The preparation of three novel alternating copoly(aromatic ester–aliphatic amide)s containing the same ordered amide–amide–ester–ester (AAEE), the same para‐disubstituted phenyl, and the different long methylene chain structure were described. 1,1′‐(Adipoyl)bisbenzotriazole (AdBBT), 1,1′‐(suberoyl)bisbenzotriazole (SuBBT), and 1,1′‐(sebacoyl)bisbenzotriazole (SeBBT) were synthesized. These diacylbenzotriazoles were preferred to aminoethanol at the amino group because of the selective N‐acylation of active acylamide of benzotriazole in excellent yield at room temperature to give diol monomers such as N,N′‐bis(2‐hydroxyethyl)adipic amide (HEAdA), N,N′‐Bis(2‐hydroxyethyl)subaric amide (HESuA), and N,N′‐bis(2‐hydroxyethyl)sebacic amide (HESeA). Polycondensation of 1,1′‐(teraphthaloyl)bisbenzotrizole (tPBT) with HEAdA, HESuA, and HESeA gave the corresponding alternating copoly(aromatic ester–aliphatic amide)s: P(tPE–AdA), P(tPE–SuA), and P(tPE–SeA), respectively. The alternating copoly(aromatic ester–aliphatic amide)s were characterized by 1H‐NMR spectra. The resulting polymers have two different chain units; one is chain unit of poly(ethylene terephthalate) and the other is a chain unit of polyamide‐2,6, polyamide‐2,8, and polyamide‐2,10; both are linked via a CN bond.
Synthesis and characterization of N‐phenylated aromatic polyureas from dianilino compounds and aromatic diisocyanates
Authors: Oishi Yoshiyuki , Kakimoto Masa‐Aki , Imai Yoshio
Published: April 2003

N‐phenylated aromatic polyureas were synthesized by the polyaddition of dianilino compounds to aromatic diisocyanates in sym‐tetrachloroethane at around 100°C. Factors that influence the reaction, such as monomer concentration, reaction solvent, catalyst, temperature, and time, were studied to optimize the conditions for the preparation of high molecular weight polymers. Compared with the analogous unsubstituted aromatic polyureas, the N‐phenylated polyureas were almost amorphous and soluble in a variety of solvents and had low glass transition temperatures. Some of the polymers could be cast into transparent flexible films from chloroform solutions.
Preparation and thermal properties of polyquinazolones containing m‐substituted phenyl groups on the quinazolone ring
Authors: Kubota Shigeru , Moriwaki Toshimoto , Ando Torahiko , Fukami Akira
Published: April 2003

Polyquinazolones containing m‐substituted phenyl groups (Br, Cl, F, CH3O, NO2, and CH3) on the quinazolone ring were synthesized in m‐cresol, and their thermal properties were studied by using dynamic thermogravimetry and isothermal weight loss. Polyquinazolones with intrinsic viscosities in the range 0.2–1.6 dL/g were synthesized. The introduction of substituted groups into the pendant phenyl group resulted in a decrease in the glass transition temperature and the thermal stability. Oxidative thermal stability of the polyquinazolones was dependent on the position of substituted groups on the pendant phenyl group. The introduction of substituted groups into the meta position reduced thermal stability more than did the introduction into the para position.
Synthesis and characterization of deuterated poly(arylene ether sulfones)
Authors: Hedrick J. L. , Dumais J. J. , Jelinski L. W. , Patsiga R. A. , McGrath J. E.
Published: April 2003

Selectively deuterated poly(arylene ether sulfones) were prepared for neutron scattering studies and for deuterium NMR investigations. The availability of these model macromolecules permits molecular‐level identification of the motions responsible for the low temperature relaxations that have been observed in the dynamic mechanical spectra of these engineering polymers. Three labeled sites on the appropriate monomers (bisphenol‐A and 4,4′‐dichlorodiphenylsulfone) were prepared from deuterated intermediates and characterized via chromatographic, spectroscopic, and thermal analysis. The deuterium exhcange between methyl and aromatic sites that occurred during synthesis was quantified. These labeled monomers were mixed with hydrogenous monomers to synthesize high molecular weight, selectively deuterated poly(arylene ether sulfones). A synthetic technique involving N‐methyl‐2‐pyrrolidone/potassium carbonate was employed to afford high molecular weight polymers. The polymers were characterized by FT‐IR, proton, carbon, and deuterium NMR, intrinsic viscosities, and thermal analysis. Molecular weights of the labeled polymers were similar to unlabeled systems.
Conducting polypeptide: Poly(L‐histidinium 7,7,8,8‐tetracyanoquinodimethanide)
Authors: Oshima Ryuichi , Kumanotani Ju
Published: April 2003

The TCNQ anion radical salt of poly(I‐histidinium) with a 1:1 stoichiometry was prepared, which exhibited some degree of crystallinity. In the salt, the helical conformation of the polycation was preserved. It showed high electrical conducivity compared to certain salts with several imidazolium derivatives.
Synthesis and characterization of fluorine‐containing aromatic polyethers from tetrafluoroisophthalonitrile and bisphenols
Authors: Shimizu Masa‐Aki , Kakimoto Masa‐Aki , Imai Yoshio
Published: April 2003

New aromatic polyethers having inherent viscosities of 0.43–0.91 dL/g were synthesized by the phase‐transfer catalyzed polycondensation of tetrafluoroisophthalonitrile with various hisphenols in a nitrobenzene‐water system. All the polyethers were amorphous and soluble in N‐methyl‐2‐pyrrolidone and nitrobenzene. They were cast into transparent and flexible films from the solutions. These polymers had glass transition temperatures around 130°C and dia not lose weight below 400°C in either air or nitrogen.
Poly(enonsulfides) from the addition of aromatic dithiols to aromatic dipropynones
Authors: Bass R. G. , Cooper E. , Hergenrother P. M. , Connell J. W.
Published: April 2003

Novel poly(enonsulfides) were prepared with inherent viscosities as high as 1.35 dL/g by nucleophilic addition of various aromatic dithiols to 1,1′‐(1,3‐ or 1,4‐phenylene)bis(3‐phenyl‐2‐propyn‐1‐one) in m‐cresol at 25–40°C. A tough clear yellow film with a tensile strength of 11,300 psi and a tensile modulus of 466,000 psi at 25°C was cast from a chloroform solution of the polymer prepared from 1,3‐dithiobenzene and 1,1′‐(1,4‐phenylene)bis(3‐phenyl‐2‐propyn‐1‐one). The poly(enonsulfides) exhibited Tg's as high as 180°C and weight losses of approximately 10% at 331°C in air. The synthesis and characterization of several poly(enonsulfides) are discussed.
Synthesis and characterization of N‐phenylated aromatic polyamides from N‐silylated dianilino compounds and aromatic diacid chlorides
Authors: Oishi Yoshiyuki , Kakimoto Masa‐Aki , Imai Yoshio
Published: April 2003

N‐Phenylated aromatic polyamides of high molecular weights were synthesized by the hightemperature solution polycondensation of N,N′ ‐di(trimethylsilyl)‐substituted dianilino compounds derived from p‐dianilinobenzene, bis(4‐anllinophenyl) ether, and α,α′‐dianilino‐p‐xylene, with isophthaloyl and terephthaloyl chloride. Almost all of the N‐phenylated polyamides were amorphous, and soluble in a variety of organic solvents including dimethylformamide, m‐cresol, and chloroform. Transparent and flexible films of these polymers could be cast from the dimethylformamide solutions. Four wholly aromatic polyamides had glass transition temperatures in the range of 195–255°C, and began to lose weight around 400°C in air.
Polymeric catenanes from crosslinked poly(2,6‐dimethyl‐1,4‐phenylene oxide) and cyclic poly(dimethylsilozane)
Authors: Fyvie T. J. , Frisch H. L. , Semlyen J. A. , Clarson S. J. , Mark J. E.
Published: April 2003

Poly(2,6‐dimethyl‐1,4‐phenylene oxide) has been crosslinked in the presence of large poly(dimethylsiloxane) cyclics (92 repeating units). Approximately 26% by weight of the cyclics were threaded and permanently captured by the polymer network forming a topological isomeric structure referred to as a polymeric catenane. Nonentrapped cyclics were extracted with chloroform. Chemical analyses and micrographs showed evidence for crosslinking and cyclic entrapment, while physical testing demonstrated distinct differences in physical properties such as the glass transition temperature, ultimate mechanical properties, and dynamic viscoelastic response between the crosslinked control samples, and those containing cyclic poly(dimethylsiloxane).
Effects of added metal ions on the interaction between polyvinylpyrrolidone and azo dyes carrying hydroxyl groups
Authors: Takagishi Toru , Matsui Naoki
Published: April 2003

The extent of binding of chrome violet, which is a monoazo dye and involves two hydroxyl groups in o and o′ positions to azo group, by polyvinylpyrrolidone is markedly enhanced in the presence of Co2+ ion. The amount of binding in the presence of 1 × 10−4 mol/L of Co2+ ion increases by a factor of about 10 compared to that in the absence of the metal ion. Ni2+ and Zn2+ ions do not perceptively influence the binding affinity of the dye. Cu2+ ion, in contrast, suppresses the binding. To investigate further the action of added metal ions, a cobalt–complex dye was prepared and its binding property for the polymer was compared to that of chrome violet in the presence of metal ions. Some possible mechanisms for the enhancement of chrome violet binding by the addition of Co2+ ion are described.
Kinetics and mechanism of urethane reactions: Phenyl isocyanate–alcohol systems
Authors: Chang Ming‐Chow , Chen Show‐An
Published: April 2003

Urethane reactions of phenyl isocyanate alcohol systems with toluene as solvent and various aprotic polar solvents (including tertiary amines) as additives were carried out at constant temperature of 10–40°C. Analysis of the variation of the second order rate constants of these systems and those available in the literature indicates that formation of the hydrogen bonding complexes (alcohol with phenyl isocyanate and with aprotic solvent) and electron donor number (DN) of the aprotic solvent are the two factors allowing satisfactory explanation of the catalysis and inhibition effects of the wide range of aprotic solvents (including amines, amides, etc.). Based on these considerations, an ion‐pair mechanism and the resulting kinetic equation for the urethane reaction are proposed. Verification on the kinetic equation with experimental results for the systems of phenyl isocyanate with alcohol in toluene (for the self catalysis of the alcohol), with dimethyl formamide and dimethyl sulfoxide in toluene (for the catalysis of the aprotic solvents), and with triethylamine in toluene (for the catalysis of the tertiary amines) shows satisfactory. In the mechanism, the aprotic solvent is considered to solvate the complex of phenyl isocyanate/alcohol at the active hydrogen to form an ion‐pair which can undergo the urethane reaction more easily.
Polymerization of cyclic acetals. I. Polymerization of 1,3,6‐trioxacyclooctane and copolymerization with p‐methoxystyrene
Authors: Velichkova R. S. , Gancheva V. B.
Published: April 2003

The polymerization of 1,3,6‐trioxacyclooctane initiated by trityl salts with various counterions in CH2Cl2 was investigated. The reaction mixtures and the isolated polymers were analyzed by GPC (double detection—IR and UV at 254 nm),1H‐, and13C‐NMR spectroscopy. In the early stage of polymerization only oligomers (mainly cyclic) were formed. With longer reaction times, linear polymers (yield 86–94%, M = 70,000–80,000) were obtained. The concentration of each individual oligomer passed through a maximum and decreased, reaching its equilibrium concentration. The time interval necessary to reach the maximum concentration increased with n. The total concentration of the oligomers was 0.2 mol L−1 regardless of the initiator used. Conditions for polymerization with virtually no termination were found. Addition of p‐methoxystyrene to the “living” polyacetals resulted in block copolymers. GPC,1H‐ and 13C‐NMR and acidolytic degradation were used to prove the formation of AB block copolymers. The reactive alkoxycarbenium growing species are responsible for the formation of block polyacetal‐polymethoxystyrene copolymer.
Surface modification by plasma techniques. I. The interactions of a hydrogen plasma with fluoropolymer surfaces
Authors: Clark D. T. , Hutton D. R.
Published: April 2003

The rapid defluorination of fluoropolymer surfaces by their exposure to a hydrogen plasma excited by an inductively coupled RF field has been studied using ESCA. The results are interpreted in terms of a reaction/depth profile; the reaction is not uniform with depth leading to the formation of an approximately 20 Å thick boundary layer of defluorinated material.
Poly(α‐amino acid)‐immobilized polymer adsorbents for optical resolution. I. Synthesis, characterization, and evaluation of poly(L‐glutamic acid) derivatives‐immobilized polymer adsorbents
Authors: Kiniwa Hideaki , Nishikaji Takashi , Ogata Naoya
Published: April 2003

As a novel polymer adsorbent for optical resolution, cross‐linked polystyrene gel incorporating poly(α‐amino acids) was synthesized. The helicity of the incorporated poly(γ‐benzyl L‐glutamate) (PBLG) was demonstrated by Fourier‐transform infrared spectroscopy. The immobilized PBLG (I) was converted to poly(L‐glutamic acid) (II) and poly(N5‐benzyl‐L‐glutamine) (III). The ability of I‐III to resolve DL‐mandelic acid was evaluated by liquid chromatography using toluene/dioxane as an eluent. Of the three resins, III resolves the recemate most effectively. In order to clarify the mechanism of chiral recognition, poly(N5‐benzyl‐D‐glutamine) and poly(N4‐benzyl‐L‐asparagine), with opposite helicity, was incorporated. In Contrast to III, these adsorbents demonstrated affinity for the L isomer. This result strongly indicates that the helical structure of the immobilized poly(α‐amino acids) is essential for chiral recognition.
Polymerization of N‐(p‐aminobenzoyl)caprolactam: Block and alternating copolymers of aromatic and aliphatic polyamides
Authors: Mathias Lon J. , Moore D. Roger , Smith Charles A.
Published: April 2003

The polymerization behavior of N‐(p‐aminobenzoyl)caprolactam was studied. It was found that polymerization could proceed by either elimination of caprolactam or by ring opening. Polymers prepared at temperatures above 200°C showed a greater tendency for ring opening to produce alternating aromatic/aliphatic copolymers than did polymers prepared at lower temperatures. Block copolymers of poly(p‐benzamide) and nylon 6 were prepared by a two‐stage hydrolytic polymerization process or by anionic polymerization at temperatures > 200°C. Polymer microstructures were determined using 13C‐NMR spectroscopy by comparison with homopolymers and model alternating copolymers. The alternating copolymer prepared by condensation of N‐(p‐aminobenzoyl)‐6‐caproic acid showed a melting transition at 300–305°C in the DSC and a Tg in subsequent heating cycles of 116–119°C. Copolymers made with the two‐stage process were rich in p‐benzamide sequences and showed no Tg or Tm below 400°C. Copolymer made with NaH was rich in nylon 6 units, showed a Tm of 175–180°C and a Tg of 80–81°C, and was homogeneous in both the melt and solid.
Polymerization of liposomes composed of diene‐containing lipids by radical initiators. II. Polymerization of monodiene‐type lipids as liposomes
Authors: Ohno Hiroyuki , Takeoka Shinji , Iwai Hidetaka , Tsuchida Eishun
Published: April 2003

1‐Palmitoyl‐2(2,4‐octadecadienoyl)‐sn‐glycero‐3‐phosphocholine (POPC), a polymerizable lipid that contains one diene group in only a 2‐acyl chain, was polymerized as liposome in an aqueous medium. Polymerization was initiated by water‐insoluble azobisisobutyronitrile (AIBN), or water‐soluble azobis(2‐amidinopropane) dihydrochloride (AAPD). AIBN was mixed with monomeric lipids, and the mixture was dispersed in an aqueous medium by sonication to prepare AIBN‐containing monomeric lipid liposomes. On the other hand, AAPD was simply added to the liposome suspension. The POPC liposomes were easily polymerized by the addition of AAPD, a water‐soluble radical initiator, but few were polymerized by AIBN. The results suggested that the diene group in the 2‐acyl chain was in an aqueous phase and, therefore, easily polymerized by a water‐soluble radical initiator. The polymerized POPC liposomes were revealed to be more stable than those of monomeric ones because the scattered‐light intensity from the polymerized POPC liposome suspension changed a little by the addition of Triton X‐100. For only the polymerized ones, the liposome structure was confirmed by TEM after addition of an excess amount of Triton X‐100.
Functional polymers and sequential copolymers by phase transfer catalysis. XXVI. Synthesis and characterization of thermotropic liquid crystalline polypodants
Authors: Shaffer Timothy D. , Percec Virgil
Published: April 2003

Thermotropic liquid crystalline (LC) polyethers and copolyethers have been synthesized from 4,4′‐dihydroxy‐α‐methylstilbene (HMS) and α,ω‐dichlorooligo(oxyethylene)s having between 2 and 5 as well as 8.7 oxyethylene units. Copolyethers were prepared from a 1:1 mol/mol ratio of two dissimilar spacers. These polymers have been prepared by a phase transfer catalyzed (PTC) polyetherification of bisphenols with these electrophiles by utilizing 50 mol% tetrabutylammonium hydrogen sulfate per phenol group. Kinetic experiments with either 5 or 50 mol% catalyst vs phenol groups in the polyetherification of 4,4%‐isopropylidenediphenol with 2‐chloroethyl ether have shown that a change in catalyst primarily affects the rate of reaction, with 50 mol % being faster. The prepared polyethers and copolyethers are soluble in common organic solvents. Both polyethers and copolyethers are crystalline. Polymers prepared to contain tetraoxyethylene spacers exhibit monotropic LC behavior. Copolymers prepared to contain tri‐ and tetraoxyethylene spacers (1 : 1 mol/mol) [PE34] were the only polymers exhibiting enantiotropic LC behavior. Longer spacers tend to destabilize the phase transitions, as suggested by the dependence of thermal transition temperatures upon the differential scanning calorimeter rate. All prepared polymers act as podants in solution, measured by picrate extraction experiments. Solid state complexes have been prepared from the polymer with a pentaoxyethylene spacer [PE5] and PE34 with LiCF3SO3. PE5 can dissolve LiCF3SO3 in the range of 0.21–2.2 mol salt/mol polymer (m.r.u.) [S/P] without the observation of free salt. PE5 complexes of/or below S/P of 0.43, upon annealing at room temperature, exhibited the two melting transitons observed in the polymer alone. PE5 complexes of/or above S/P of 0.77 only exhibited a Tg. The Tg of PE5 complexes were found to change nonlinearly with S/P, while Tm1 changed linearly. Tm2 was independent of S/P. Only one complex with PE34 gave two transitions (Tm2,Ti) in dynamic DSC experiments. Other PE34 complexes followed a behavior similar to PE5 complexes.
Polymerization of N‐methylpyrrole with bis‐triazolinediones via electrophilic aromatic substitution
Authors: Mallakpour Shadpour E. , Butler George B.
Published: April 2003

The reaction of N‐methylpyrrole with 4‐substituted‐1,2,4‐triazoline‐3,5‐diones (4R‐TDs), i.e., MeTD (4‐methylsubstituted) and PhTD (4‐phenyl substituted), at room temperature without use of any catalyst was investigated. The reaction is instantaneous and leads to the formation of a 2:1 adduct in high yield, with substitution occurring at the 2 and 5 positions of the pyrrole moiety via electrophilic aromatic substitution. These compounds were fully characterized by IR,13C‐NMR,1H‐NMR, and elemental analysis, and were used as model compounds for the polymerization reaction. The reaction of bis‐triazolinediones with N‐methylpyrrole was carried out in dimethylformamide at room temperature. The reactions are fast and give novel polymer structures. Some structural characterization and physical properties of these new polymers are reported.
TiO2‐, ZnO‐, and CdS‐photocatalyzed oxidation of ethylene‐propylene thermoplastic elastomers
Authors: Lacoste Jacques , Singh Raj Pal , Boussand Jacques , Arnaud Rene
Published: April 2003

The ZnO‐, TiO2‐, and CdS‐photocatalyzed oxidations of an amorphous ethylene‐propylene copolymer (EP copolymer) containing 75% w/w of ethylene are described. In solid films exposed under polychromatic (λ > 300 nm) or monochromatic (λ = 365 nm) UV light, it is observed that the introduction of pigment (0.5–5% w/w) strongly modified the course of the photooxidation of a transparent sample. Ketonic and lactonic groups accumulate in the polymer matrix without being converted photochemically into acidic, ester, and vinyl groups. In the kinetic study it is pointed out that the variations of the rate of formation of carbonyl groups depend on the nature of the pigment. With highly photoactive pigments (ZnO and untreated TiO2 RL11A), the rate is at first a decreasing function of the pigment percent, then an increasing function. With poorly photoactive pigments (treated TiO2 RL90 and CdS), the rate of formation of carbonyl groups is a decreasing function of the pigment content. It is therefore emphasized that, at a low pigment content, the inner filter effect prevails over the photocatalytic influence with any pigment. It is also observed that the rate of formation of vinyl groups, photoproducts formed from the excited ketones, is a monotonously decreasing function of the pigment content. The complete inhibition of the ketone photochemistries is observed with ZnO in conditions in which the light is not absorbed by the pigment, suggesting that the carbonyl groups formed are adsorbed on the pigment.
Reaction of α,β‐poly(N‐hydroxyethyl)‐DL‐aspartamide with derivatives of carboxylic acids
Authors: Giammona Gaetano , Carlisi Bianca , Palazzo Salvatore
Published: April 2003

Benzoic acid, acetylsalicylic acid, and 4‐acetamidobenzoic acid have been covalently linked by ester bonds to α,β‐poly(N‐hydroxyethyl)‐DL‐aspartamide (PHEA), a water soluble and nontoxic polymer, in order to study PHEA as a drug carrier.
Syntheses and some spectroscopic properties of polyanions with pendant merocyanine dyes
Authors: Kobayashi Takaomi , Morishima Yotaro , Nozakura Shun‐Ichi
Published: April 2003

Polymers tagged with a local pH reporter were synthesized. A methacrylate‐type monomer containing a merocyanine dye residue as a reporter dye—1‐(2‐methacryloyloxyethyl)‐4‐(2‐(4‐hydroxyphenyl)‐ethenyl)quinolinium bromide—was synthesized. Its homopolymer and copolymers with sodium 2‐acrylamido‐2‐methylpropanesulfonate were prepared by free radical polymerization. These polymers showed a characteristic color change in aqueous solutions from yellow to red with increasing pH from acidic to basic conditions according to the acid‐base equilibria of the merocyanine dye residues. Since the electrostatic potential and polarity of media have a strong effect on the acid–base equilibria, the pendant merocyanine residues are expected to serve as a reporter to provide information on the local environments around the polymer chain at which the dye molecules are incorporated.