bluuebunny/crossref_metadata_2025 huggingface dataset:
Syntheses and properties of aromatic polyamides and polyimides based onN‐phenyl‐3,3‐bis[4‐(p‐aminophenoxy) phenyl] phthalimidine
Authors: Yang Chin‐Ping , Lin Jiun‐Hung
Published: April 2003

N‐Phenyl‐3,3‐Bis[4‐(p‐aminophenoxy)phenyl] phthalimidine (II) was used as a monomer with various aromatic dicarboxylic acids and tetracarboxylic dianhydrides to synthesize polyamides and polyimides, respectively. The diamineIIwas derived by a nucleophilic substitution ofN‐phenyl‐3,3‐bis(4‐hydroxyphenyl) phthalimidine withp‐chloronitrobenzene in the presence of K2CO3and then hydro‐reduced. PolyamidesIVa‐ghaving inherent viscosities of 0.55–1.64 dL/g were prepared by the direct polycondensation of the diamineIIwith various aromatic diacids using triphenyl phosphite and pyridine as condensing agents. All the aromatic polyamides were amorphous and readily soluble in various polar solvents such asN,N‐dimethylacetamide (DMAc),N,N‐dimethylformamide, dimethylsulfoxide, andN‐methyl‐2‐pyrrolidone (NMP). Transparent and flexible films of these polymers could be cast from the DMAc solutions. These aromatic polyamides had glass transition temperatures in the range of 293–319°C and 10% weight loss occurred up to 480°C. The polyimides were synthesized from diamine II and various aromatic dianhydrides via the two‐stage procedure that included ring‐opening polyaddition in DMAc to give poly(amic acid)s, followed by thermal or chemical conversion to polyimides. Most of the aromatic polyimides obtained by chemical cyclization were found to be soluble in NMP,m‐cresol, ando‐chlorophenol. These polyimides showed almost no weight loss up to 500°C in air or nitrogen atmosphere. © 1994 John Wiley & Sons, Inc.
Polyisobutylene‐containing block polymers by sequential monomer addition. X. Synthesis of poly(α‐methylstyrene‐b‐isobutylene‐b‐α‐methylstyrene) thermoplastic elastomers
Authors: Tsunogae Yasuo , Kennedy J. P.
Published: April 2003

Preparatory to triblock synthesis experiments, the cationic polymerization of α‐methylstyrene (αMeSt) was investigated using the 2‐chloro‐2,4,4‐trimethylpentane (TMPCI)/TiCl4 initiating system in the presence of triethylamine (Et3N) as electron donor (ED) and CH3Cl/n‐hexane mixed solvent in the −80 to −40°C range. Conversions are influenced by temperature, [TiCl4], [Et3N], and [αMeSt]. The polymerization of αMeSt is living at −80°C: Both termination and chain transfer to monomer are frozen out, however, initiation is slow relative to propagation. Highly syndiotactic (>94%) Pα Mest was obtained. At−60deg;C initiator efficiency is ca. 100%, but termination becomes evident. Et3N may act both as Ed and as proton scavenger. Novel poly(α‐methystyrene‐b‐isobutylene‐b‐α‐methylstyrene) (PαMeSt‐PIB‐PαMeSt) triblocks have been synthesized by adding αMeSt to biliving polyisobutylene carbocations (⊕PIB⊕) in the −80 to −40°C range. The effects of temperature, solvent polarity, and [Et3N] on the block copolymerization have been investigated. At −80°C, the rate of crossover from ⊕PIB⊕ to αMeSt is lower than that of propagation of PαMeSt⊕, so that the triblock is contaminated by PIB and PIB‐b‐PαMeSt. At −60°C, crossover occurs preferentially. The rate of propagation relative to that of crossover is also reduced by lowering the solvent polarity and increasing the [Et3N]. High crossover efficiency and blocking efficiency can be obtained under optimum blocking conditions. The triblocks are novel thermoplastic elastomers (TPEs). © 1994 John Wiley & Sons, Inc.
Electrically conductive composite prepared by template polymerization of pyrrole into a complexed polymer
Authors: Mohammadi A. , Paul D. W. , Inganäs O. , Nilsson J. O. , Lundström I.
Published: April 2003

Electrically conducting polymer composite films have been synthesized by the exposure of poly(4‐vinylpyridine) complexed with cupric ions to pyrrole and water vapor. To immobilize a stoichiometric amount of the oxidant inside the polymer matrix, the ratio of poly(4‐vinylpyridine)/cupric ion = 1.8 was chosen. Polypyrrole was formed in this tailored structure by a template polymerization process. Opaque polymer composite films with electrical conductivity up to 60 (Ω cm)−1 have been obtained by this method, However, slightly colored transparent composite thin films with a conductivity as high as 50 (Ω cm)−1 were also produced. The electrically conducting polymer composite films and the metal‐polymer complex have been characterized by XPS and IR spectroscopy, elemental analysis, EDX, and scanning electron microscopy. The polymerization process was also followed by use of a quartz crystal microbalance. © 1994 John Wiley & Sons, Inc.
Modification of poly(epichlorohydrin) with nadimide derivatives and their curing reaction
Authors: Galià M. , Mantecón A. , Cádiz V. , Serra A.
Published: April 2003

Chemical modification of poly(epichlorohydrin) (PECH) with nadimide derivatives using 1,8‐diazabicyclo (5.4.0)−7 undecene to catalyze the substitution of the chlorine atom by acid compounds (DBU method) was accomplished. The linear polyethers obtained showed a degree of substitution from 5–80%, depending on time and temperature reaction. The Tg of modified polymers and Ea, calculated in the cure reactions, increases with substitution degree. Residual enthalpies were observed in all cases, which suggests that the curing reaction is incomplete. TGA measurements showed that the degradation has a greater dependence on the modification degree than on the introduced pendant group. © 1994 John Wiley & Sons, Inc.
Polymers incorporating backbone thiophene, furan, and alcohol functionalities formed through chemical modifications of alternating olefin–carbon monoxide copolymers
Authors: Jiang Zhaozhong , Sanganeria Siddharth , Sen Ayusman
Published: April 2003

The reaction of the alternating ethylene–carbon monoxide copolymer with Lawesson's reagent resulted in the conversion of 75% of the carbonyl groups to thiophene units. A few thioketone groups were also present in the derived polymer. A polymer with furan units in the backbone was formed upon treatment of the alternating propylene–carbon monoxide copolymer with P2O5. Depending on the reaction conditions, up to 90% of the carbonyl groups were converted. Finally, 1,4‐polyalcohols were prepared from the alternating propylene‐carbon monoxide copolymer by reduction. Hydrogenation using Raney nickel as catalyst resulted in the reduction of 60% of the carbonyl groups, whereas reaction with LiAlH4 at room temperature caused the reduction of 85% of the carbonyl groups. The glass transition temperature was found to increase monotonically with increasing concentration of hydroxyl groups in the polymer backbone. © 1994 John Wiley & Sons, Inc.
Synthesis of graft copolymers having phospholipid polar group by macromonomer method and their properties in water
Authors: Ishihara Kazuhiko , Tsuji Tsuyoshi , Sakai Yuko , Nakabayashi Nobuo
Published: April 2003

Water‐soluble graft copolymers with phospholipid polar group were synthesized by the macromonomer method and their properties in water were investigated by surface tension and fluorescence spectroscopic measurements. At first, 2‐methacryloyloxyethyl phosphorylcholine (MPC) was polymerized in the presence of 3‐mercapt propionic acid as a chain transfer agent and carboxyl group‐terminated oligo (MPC) was obtained. The oligo (MPC) reacted with glycidyl methacrylate to convert the carboxyl group to a polymerizable methacryloyl group. The MPC macromonomer obtained was copolymerized with hydrophobic n‐butyl methacrylate (BMA) and a graft copolymer was obtained. The graft copolymer, poly(MPC‐graft‐BMA), was water‐soluble when the MPC unit mole fraction was above 0.40. The surface tension of the aqueous solution of poly(MPC‐graft‐BMA) did not depend on the polymer concentration below 0.1 wt %. This tendency was the same as that which appeared in aqueous poly(MPC) solution. The fluorescence intensity of hydrophobic probes observed in an aqueous solution of the poly (MPC‐graft‐BMA) was also the same level as that observed in the case of poly(MPC). These results clearly indicated that the poly(MPC‐graft‐BMA) took a domain structure like micelle in water, i.e., the hydrophobic poly(BMA) backbone was in the core part and the hydrophilic poly(MPC) chain formed the shell part of the micelle. © 1994 John Wiley & Sons, Inc.
Synthesis and characterization of new aromatic polyesters and polyethers derived from 1,2‐bis(4‐hydroxyphenyl)‐1,2‐diphenylethylene
Authors: Watanabe Shinji , Kobayashi Atsushi , Kakimoto Masa‐Aki , Imai Yoshio
Published: April 2003

New polyarylates and aromatic polyethers were synthesized from 1,2‐bis(4‐hydroxyphenyl)‐1,2‐diphenylethylene, and aromatic dicarboxylic acid chlorides and aromatic dihalides, respectively. The polyarylates having inherent viscosities of 0.28–1.05 dL/g were synthesized by either the two‐phase method or the high‐temperature solution method. All the polymers were easily soluble in N‐methyl‐2‐pyrrolidone, N,N‐dimethylformamide, pyridine, m‐cresol, 1,4‐dioxane, and 1,1,2,2‐tetrachloroethane. They have glass transition temperatures in the range of 217–250°C and showed no weight loss below 315°C in both air and nitrogen atmospheres. Aromatic polyethers with inherent viscosities of 0.85–1.21 dL/g were obtained by the polycondensation of 1,2‐bis(4‐hydroxyphenyl)‐1,2‐diphenylethylene and aromatic difluorides in the presence of potassium carbonate. These polymers having glass transion temperatures of 193–220°C were also soluble in the aforementioned solvents and stable up to around 350deg;C in both atmospheres. © 1994 John Wiley & Sons, Inc.
Phenolic materials via ring‐opening polymerization: Synthesis and characterization of bisphenol‐A based benzoxazines and their polymers
Authors: Ning Xin , Ishida Hatsuo
Published: April 2003

Compounds with bifunctional benzoxazine groups in their molecular structures form crosslinked structures characteristic of phenolic materials through a ring‐opening reaction mechanism. This family of compounds offers greater flexibility than conventional novolac or resole resins in terms of molecular design. It is also superior to conventional phenolic resin in process control since it releases no by‐product during curing reactions. The materials thus obtained exhibit excellent mechanical integrity with glass transition temperatures over 200°C. The synthesis, composition, and structural analysis of precursors based on bisphenol‐A are discussed herein. © 1994 John Wiley & Sons, Inc.
Comparative characterization of MgCl2/ethyl benzoate/TiCl4 and MgCl2/2,2,6,6 tetramethylpiperidine/TiCl4 Ziegler‐Natta precatalysts
Authors: Ferreira Maŕia L. , Damiani Daniel E.
Published: April 2003

In this article we present the results of the preparation and characterization of two Ziegler–Natta precatalysts: MgCl2/Ethyl benzoate (EB)/TiCl4 and MgCl2/2,2,6,6 tetramethylpiperidine (TMPiP)/TiCl4 by means of FTIR, X‐ray diffraction, SEM, BET surface area measurements, and other techniques applied at different steps of their preparation procedures.

The precatalysts were prepared by impregnating with TiCl4 a given amount of MgCl2, which was previously ball‐milled with the electron donor chosen.

Prior to impregnation, the ball‐milled material presented different surface compounds depending on the electron donor used: [(MgCl2)2] · 2EB, MgCl2 · EB, or a salt of the amine. The solid milled with EB is more homogeneous than the one milled with the TMPiP.

Titanium is better retained in the solid milled with EB. This precatalyst has better morphological properties and larger BET surface area. By means of FTIR, we found evidences that an adequate surface structure for the formation of stereospecific sites in MgCl2/TMPiP/TiCl4 was formed. © 1994 John Wiley & Sons, Inc.
Curing of epoxidized natural rubber with p‐phenylenediamine
Authors: Hashim A. S. , Kohjiya S.
Published: April 2003

The curing of epoxidized natural rubber with p‐phenylenediamine catalyzed by bisphenol A was investigated. The curing reaction was found to be first order with respect to the amine and to have an activation energy of 67.5 kJ/mol. Vulcanizates of tensile strength 12.5–16.0 MPa were obtained at cure times of 30–75 min at 180°C. The amine‐cured vulcanizate was observed to be more rigid than the sulfur‐cured one at room temperature consistent with its relatively high Tg. Stress‐strain analysis and dynamic mechanical properties indicated that the high Tg of the amine‐cured vulcanizate could be attributed to the bulky amine crosslinks and hydrogen bonding effect of bisphenol A. © 1994 John Wiley & Sons, Inc.
Thermodynamic studies of some complexation systems involving methacrylic acid‐acrylamide copolymer, poly(vinyl pyrrolidone) and poly(ethylene oxide)
Authors: Chatterjee S. K. , Chhabra Mamta , Johri Shalini
Published: April 2003

Interpolymer complexes of methacrylic acid‐acrylamide copolymer have been prepared by the interaction of its comonomer units with two different homopolymers, and also with a single homopolymer. The stability constants and related thermodynamic parameters (e.g., ΔH0 and ΔS0) of the mixed complex were found to be significantly different from the single homopolymer complexes. This has been attributed to neighboring group influence and destabilization of various interacting forces at different temperatures. © 1994 John Wiley & Sons, Inc.
Thermally initiated frontal polymerization of transition metal nitrate acrylamide complexes
Authors: Savostyanov V. S. , Kritskaya D. A. , Ponomarev A. N. , Pomogailo A. D.
Published: April 2003

The effect of the thermally initiated frontal polymerization of acrylamide complexes of transition metal nitrates such as those of Mn(II), Co(II), Ni(II), and Zn(II) was disclosed. The rate of the polymerization front propagation was found to be 2−9 × 10−2cm/c, depending appreciably on sample diameter and density, as well as the presence of radical inhibitor additives. The rate was found to decrease in the series: Co(II) > Ni(II) > Mn(II) > Zn(II). Polymerization was shown to occur directly in the melting region of a complex at 80–100°C to give three‐dimensional polymers. A mechanism of the polymerization being initiated with the products of the partial nitrate group decomposition was proposed. © 1994 John Wiley & Sons, Inc.
The effect of the nature of organoaluminium compound and the catalytic system preparation procedure on molecular characteristics of 1,4‐Cis‐polybutadiene
Authors: Kozlov V. G. , Sigaeva N. N. , Nefedjev K. V. , Savel'eva I. G. , Marina N. G. , Monakov Yu. B.
Published: April 2003

This study investigated the effect produced by the preparation procedure of a 2‐component lanthanide catalytic system and by the nature of organoaluminium compound on 1) the molecular characteristics of 1,4‐cis‐polybutadiene (PB), 2) the regularities of its average molecular weight (MW), and 3) molecular weight distribution (MWD). The kinetic parameters of the polymerization process were calculated. The principal regularities of variations in PB molecular characteristics with respect to the polymerization conditions, i.e., OAC and monomer concentrations and temperature, are retained with different procedures of the lanthanide catalytic system, and those present distinctive features of the catalytic complexes studied in this article. But as for differences in MW and its patterns of dependence on monomer conversion rate and OAC nature, these are due to changes in kinetic parameters of the polymerization, which occur with the use of the catalyst prepared by a different procedure. © 1994 John Wiley & Sons, Inc.
Kinetics of polymerization of 1‐octene with Mgcl2‐supported Ticl4 catalysts
Authors: Kothandaraman H. , Devi M. Saroja
Published: April 2003

A number of TiCl4 catalysts supported on MgCl2 which was activated by the recrystallization method using different alcohols were prepared with ethyl benzoate or dibutyl phthalate as the internal electron donor. All the catalysts were characterized by BET, x‐ray diffraction, and hydrolysis–GC analysis. Kinetics of polymerization of 1‐octene was studied with three of the above catalysts (having different internal electron donors) activated by AlEt3. The rate of polymerization increased linearly with increasing temperature, and catalyst and monomer concentrations. From the Arrhenius plot, the overall activation energies of polymerization were determined and the dependence of rate on the AlEt3 concentration could be explained by the Langmuir‐Hinshelwood mechanism. 13C‐NMR was used to study the effect of internal electron donors on the % isotacticity of poly(1‐octene). The catalytic activities of all the catalysts were compared in 1‐octene polymerization. © 1994 John Wiley & Sons, Inc.
Electrical conductivity of iodine‐doped pseudo interpenetrating polymer networks of poly‐(carbonate‐urethane) and natural rubber
Authors: Frisch H. L. , Chen Z. J.
Published: April 2003

Recent DC conductivity measurements on iodine‐doped full and psuedo IPNs of poly (carbonate‐urethane) (PCU) and natural rubber (NR) reveal that these materials possess a modest conductivity. Both such full and pseudo IPNs (with linear NR chains) are single‐phased materials if the NR is of sufficiently high molecular weight derived from Brazilian Manihot glaziovii. On iodine doping the electrical conductivity rises eight orders of magnitude of both the full IPN (to ca. 10−5S cm−1) and the pseudo IPN (to ca. 10−4 S cm−1). A simple theory based on the assumption that conduction occurs essentially along the linear NR chains, composing a percolation cluster, in the iodine‐doped pseudo IPNs of PCU and NR accounts for the observed electrical conductivity dependence on temperature, iodine molality, and weight fraction of NR. As temperature decreases the DC conductivity falls and the material becomes essentially an insulator. At sufficiently low temperature (ca. 115 K) this trend reverses and the DC conductivity rises by two orders of magnitude with further decreasing temperature up to that of liquid helium. © 1994 John Wiley & Sons, Inc.
Chemical modification of poly(2,6‐dimethyl‐1,4‐phenylene oxide) by bromination‐alkynylation
Authors: Bonfanti C. , Lanzini L. , Roggero A. , Sisto R.
Published: April 2003

The chemical modification of poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) by bromination of the aromatic ring, followed by displacement of bromine with substituted acetylenes, has been investigated. This pathway leads to a series of novel copolymers containing substituted alkynes on the aromatic ring. The degree of bromination and alkynylation, determined by 1H‐NMR, was in the range of 20–85 and 15–80%, respectively. 13C‐NMR and FT‐IR unambiguously elucidated the structure of the alkynylated polymers. Finally, thermal properties and permeation properties of substituted PPO to carbon dioxide, methane, oxygen, and nitrogen are reported. © 1994 John Wiley & Sons, Inc.
A multi‐technique study of the spontaneous oxidation of N‐hexane plasma polymers
Authors: Gengenbach Thomas R. , Vasic Zoran R. , Chatelier Ronald C. , Griesser Hans J.
Published: April 2003

Long‐term compositional changes were observed when n‐hexane plasma polymers were stored in air at ambient temperature. These post‐deposition changes were monitored over periods exceeding one year using XPS, grazing angle FTIR, and SEM. A rapid initial increase in the oxygen content was followed by a slower oxygen uptake, which continued for many months. In contrast to the reported autocatalytic acceleration of the oxidation of polyolefins, the rate of oxidation of n‐hexane plasma polymers was found to decrease continuously, and it did not proceed to the same extent toward higher oxidation states. The plasma polymer coatings did not show physical manifestations of oxidative degradation such as cracking, reduction in thickness, or loss of physical integrity. Comparison of the XPS and FTIR data suggested that the top few nanometers of the plasma polymer coatings oxidized at a faster rate than the “bulk.” The experimental data were interpreted using a model comprising reactions known from the oxidative degradation of polyolefins: carbon‐centered radicals, trapped in the course of the plasma deposition, combine with atmospheric oxygen to form metastable peroxy radicals and hydroperoxides, which decompose to generate a variety of stable product groups such as hydroxyl, carbonyl, and carboxylic groups. There was broad agreement between the XPS data and the time dependence of particular species in model calculations. © 1994 John Wiley & Sons, Inc.
Synthesis and characterization of poly(urethane‐sulfone)s
Authors: Zhang Tianhong , Litt Morton H. , Rogers Charles E.
Published: April 2003

Eight poly(urethane‐sulfone)s were synthesized from two sulfone‐containing diols, 1,3‐bis(3‐hydroxypropylsulfonyl)propane (Diol‐333) and 1,4‐bis(3‐hydroxypropylsulfonyl)butane (Diol‐343), and three diisocyanates, 1,6‐hexamethylene diisocyanate (HMDI), 4,4′‐diphenylmethane diisocyanate (MDI), and tolylene diisocyanate (TDI, 2,4‐ 80%; 2,6‐20%). As a comparison, eight polyurethanes were also synthesized from two alkanediols, 1,9‐nonanediol and 1,10‐decanediol, and three diisocyanates. Diol‐333 and Diol‐343 were prepared by the addition of 1,3‐propanedithiol or 1,4‐butanedithiol to allyl alcohol and subsequent oxidation of the resulting sulfide‐containing diols. The homopoly(urethanesulfone)s from HMDI and MDI are semicrystalline, and are soluble in m‐cresol and hot DMF, DMAC, and DMSO. The copoly(urethane‐sulfone)s from a 1/1 molar ratio mixture of Diol‐333 and Diol‐343 with HMDI or MDI have lower crystallinity and better solubility than the corresponding homopoly(urethane‐sulfone)s. The poly(urethane‐sulfone)s from TDI are amorphous, and are readily soluble in m‐cresol, DMF, DMAC, and DMSO at room temperature. Differential scanning calorimetry data showed that poly(urethane‐sulfone)s have higher glass transition temperatures and melting points than the corresponding polyurethanes without sulfone groups. The rise in glass transition temperature is 20–25°C while the rise in melting temperature is 46–71°C. © 1994 John Wiley & Sons, Inc.
Polymerization photoinitiated by carbonyl compounds. X. Methyl methacrylate polymerization photoinitiated by fluorenone in the presence of triethylamine
Authors: Encinas M. V. , Lissi E. A. , Rufs A. M. , Previtali C. M.
Published: April 2003

The photoinitiation efficiency of the fluorenone/triethylamine (TEA) system in the polymerization of methylmethacrylate (MMA) has been evaluated as a function of the monomer concentration, the amine concentration, and the polarity of the reaction medium. The polymerization proceeds readily in low polarity media (benzene/monomer), but it is negligible in more polar solvents (acetonitrile/monomer). The polymerization rate increases with the amine concentration up to 0.01 M TEA. Further increase in amine concentration produces a decrease in the polymerization rate. A similar behavior was observed for the fluorenone photoreduction yield and the yield of fluorenone derived radicals. All these processes are considered to involve the excited triplet, while quenching of the excited singlet by the amine decreases the rate of these processes. However, the decrease in photoinitiation efficiency observed at high amine concentration is larger than that expected from the singlet quenching extent, as estimated from the effect of the amine on the fluorescence yield under the same experimental conditions. This discrepancy indicates that other process(es) must contribute to the protection afforded by high amine concentrations. Quenching of the charge transfer intermediate by the amine is postulated as a competitive process that could explain the above mentioned effects. © 1994 John Wiley & Sons, Inc.
Surface modification of polyethylene fiber by graft polymerization
Authors: Mori Masaru , Uyama Yoshikimi , Ikada Yoshito
Published: April 2003

To improve the wettability and adhesion, graft polymerization of acrylamide (AAm) and glycidyl methacrylate (GMA) was performed onto the surface of ultra‐high modulus polyethylene (UHMPE) fiber pretreated with Ar plasma. Following the plasma treatment and the subsequent exposure to air to introduce peroxides onto the fiber surface, graft polymerization onto the UHMPE fiber was allowed to proceed from the polymer peroxides either in deaerated monomer solution at an elevated temperature (degassing method), or in aerated monomer solution containing riboflavin at 30°C under UV irradiation (photoinduction method). The monomer solution was prepared from water and dioxane for AAm and GMA, respectively. After rigorous removal of homopolymers, surface analysis of the grafted fibers was performed with ATR‐FTIR and XPS, which revealed that PAAm and PGMA chains were grafted in the surface region of fibers. The grafting rate of PAAm by the photoinduction method was much higher than that by the degassing method when compared at the same concentration of the AAm solution. The amount of PGMA grafted was greatly affected by UV irradiation time, but depended on plasma treatment time to an insignificant extent if the treatment was carried out for longer than 30 s. Reaction of propylamine with the PGMA‐grafted surface resulted in the appearance of a nitrogen peak in the XPS spectrum, suggesting the presence of epoxy groups on the surface of PGMA grafted fiber. © 1994 John Wiley & Sons, Inc.
Polymerizability of norbornene in ring‐opening metathesis polymerization initiated by Mo‐based complexes
Authors: Heroguez Valérie , Fontanille Michel
Published: April 2003

Concerning the study on the relation between structural parameters and reactivity in ring‐opening metathesis polymerization of cyclo‐olefins, the “living” polymerization of norbornene initiated by Schrock's‐type complexes was considered as a reference and studied from the kinetic point of view. First kinetic orders with respect to both monomer and active species allow the values of absolute rate constants of propagation to be determined. The thermodynamic parameters obtained from kinetic experiments performed at different temperatures seem to indicate that monomer coordination and metallacycle formation are rate‐determining steps in the process studied. © 1994 John Wiley & Sons, Inc.
Primary thermal degradation processes occurring in poly(phenylenesulfide) investigated by direct pyrolysis–mass spectrometry
Authors: Montaudo Giorgio , Puglisi Concetto , Samperi Filippo
Published: April 2003

The thermal degradation Processes which occur in poly(phenylenesulfide) (PPS) have been studied by direct pyrolysis‐mass spectrometry (DPMS). The structure of the compounds evolved in the overall temperature range of PPS decomposition (400–700°C) suggests the occurrence of several thermal decomposition steps. At the onset of the thermal degradation (430–450°C) this polymer decomposes with the formation of cyclic oligomers, generated by a simple cylization mechanism either initiated at the—SH end groups or by the exchange between the inner sulfur atoms along the polymer chain. At higher temperature (> 500°C) another decomposition reaction takes over with the formation of aromatic linear thiols. The formation of thiodibenzofuran units by a subsequent dehydrogenation reaction occurs in the temperature range of 550–650°C; in fact, pyrolysis products with a quasi‐ladder structure have also been detected. Ultimately, above 600°C, extrusion of sulfur from the pyrolysis residue occurs with the maximum evolution at the end of decomposition (about 700°C). It appears, therefore, that the residue obtained at high temperature tends to have a crosslinked graphite‐like structure from which the bonded sulfur is extruded. © 1994 John Wiley & Sons, Inc.
Penetration of plasma surface modification. II. CF4 and C2F4 low‐temperature cascade arc torch
Authors: Krentsel E. , Fusselman S. , Yasuda H. , Yasuda T. , Miyama M.
Published: April 2003

The depth of surface modification by low‐temperature cascade arc torch is investigated. A stack of 10 sheets of nonwoven fabrics of polyester fibers is exposed to a low‐temperature cascade arc torch containing CF4 or C2F4, and the fluorination effect is examined by ESCA. It is shown that interaction of chemically reactive species, created in a low‐temperature cascade arc torch, with the surface is not limited to the surface contacted by the torch (flame). The results indicate that the fluorination effect is observed on surfaces which are shadowed from the torch by overlying fibers. The highest degree of fluorination is found on the second layer, rather than on the first layer which the torch contacts directly. No significant differences in the trends of penetration of CF4 and C2F4 treatment through porous samples are observed. However, ESCA data show principal differences in chemical structures of the surfaces treated with CF4 (nonpolymer‐forming gas) and C2F4 (polymer‐forming gas). These results indicate that chemically reactive species induced by the excited species of argon rather than primary species created by the ionization process seem to play predominant roles in the surface treatment as well as the low‐temperature cascade arc torch polymerization of perfluorinated compounds. © 1994 John Wiley & Sons, Inc.
Effect of polarity of the medium on the stereospecific polymerization of propylene by ansa‐zirconocene catalyst
Authors: Vizzini James C. , Chien James C. W. , Babu Gaddam N. , Newmark Richard A.
Published: April 2003

Propylene was polymerized with rac‐ethylene‐bis (1‐η5‐indenyl)dichlorozirconium/methylaluminoxane in solvents of different polarity. The poly (propylene) formed was separated by solvent extraction; 13C‐NMR and DSC measurements were made on the polymer fractions. The poly(propylene) in each solvent fraction has its characteristic molecular weight steric pentad distributions, melting transition temperature, and enthalpy for fusion irrespective of the polymerization medium. The results suggest that the medium dielectric constant does not affect the polymerization rate or the intrinsic stereoselectivity, propagation and chain transfer rates a given catalytic species but can alter the occurrence of steric insertion errors through shifting of distributions of the propagating species producing poly(propylenes) of different stereoregularities. © 1994 John Wiley & Sons, Inc.
Determination of the reactivity ratios of methyl acrylate with the vinyl acetate, vinyl 2,2‐dimethyl‐propanoate, and vinyl 2‐ethylhexanoate
Authors: Noël Lilian F. J. , Van Altveer Jeroen L. , Timmermans Menno D. F. , German Anton L.
Published: April 2003

The course of composition drift in copolymerization reactions is determined by reactivity ratios of the contributing monomers. Since polymer properties are directly correlated with the resulting chemical composition distribution, reactivity ratios are of paramount importance. Furthermore, obtaining correct reactivity ratios is a prerequisite for good model predictions. For vinyl acetate (VAc), vinyl 2,2‐dimethyl‐propanoate also known as vinyl pivalate (VPV), and vinyl 2‐ethylhexanoate (V2EH), the reactivity ratios with methyl acrylate (MA) have been determined by means of low conversion bulk polymerization. The mol fraction of MA in the resulting copolymer was determined by 1H‐NMR. Nonlinear optimization on the thus‐obtained monomer feed–copolymer composition data resulted in the following sets of reactivity ratios: rMA = 6.9 ± 1.4 and rVAc = 0.013 ± 0.02; rMA = 5.5 ± 1.2 and rVPV = 0.017 ± 0.035; rMA = 6.9 ± 2.7 and rV2EH = 0.093 ± 0.23. As a result of the similar and overlapping reactivity data of the three methyl acrylate–vinyl ester monomer systems, for practical puposes these data can be described with one set of reactivity data. Nonlinear optimization of all monomer feed–copolymer composition data together resulted in rMA = 6.1 ± 0.6 and rVEst = 0.0087 ± 0.023. © 1994 John Wiley & Sons, Inc.
Emulsion copolymerization of tetrafluoroethylene and propylene with redox system containing tert‐butylperbenzoate. I. Polymerization conditions and components
Authors: Kostov G. K. , Chr. Petrov P.
Published: April 2003

Emulsion polymerization of tetrafluoroethylene and propylene with ammonium perfluorooctanoate, initiated by a redox system containing tert‐butylperbenzoate (TBPB) was carried out. The effect of the components of the redox system Is (TBPB, FeSO4.7H2O, ethylenediamine tetraacetic acid (EDTA), and CH2(OH)SO2Na.2H2O) on the polymerization rate (R) and molecular weight ($\[ \bar M_n \] $) was studied. Among redox system components, Fe2+ concentration exerts the most significant effect (by power of 0.54) on the polymerization rate. It was found that R ∝ [Is]0.2–0.54 and Mn ∝ [Is]0.0–0.1 and polymerization reaction scheme was suggested for the action of the initiating system. The influence of the copolymerization conditions (pressure, temperature, stirring speed, and pH) is also discussed. The apparent activation energy of the reaction was found to be 46.0 kJ/mol. © 1994 John Wiley & Sons, Inc.
Emulsion copolymerization of tetrafluoroethylene and propylene with redox system containing tert‐butylperbenzoate. II. Polymerization mechanism
Authors: Chr. Petrov P. , Kostov G. K.
Published: April 2003

Emulsion copolymerization of tetrafluoroethylene (TFE) and propylene (P) initiated by trilon‐rongalite catalytic system containing tert‐C4H9OH, initial monomer mixture, emulsifier (C7F15COONH4) concentration, and monomer mixture/water ratio on the polymerization rate (R) and molecular weight (M̄n
) was investigated. Both R and M̄n increased considerably with TFE content in monomer mixture up to 75 mol %. Alternating rubber‐like copolymers in a wide range of initial monomer mixture (from 55–85 mol %) were obtained. The reactivity ratio was found to be rTFE = 0.005 ± 0.04 and rp = 0.17 ± 0.07. Above the critical miscelle concentration, the effects of the initiating system Is and emulsifier Cs on R and M̄n were found to obey the following relations:

according to which emulsion copolymerization proceeds by the I case of Smith‐Ewart theory. Polymerization mechanism of the reaction studied was suggested. The copolymerization is mainly terminated by degradative chain transfer of the propagating radicals to propylene. © 1994 John Wiley & Sons, Inc.
Spectroscopic evidences for grafting of N‐vinyl carbazole on cellulose‐acetate film
Authors: Basu Samita , Bhattacharyya Amit , Mondal Parikshit Ch. , Bhattacharyya Sudhindra Nath
Published: April 2003

N‐vinyl carbazole (VCZ) was grafted on cellulose acetate film using simultaneous cobalt‐60‐γ ray irradiation grafting technique. Absorption, excitation, and emission spectral studies on the grafted film were carried out to ascertain the grafting of VCZ on the polymer matrix. Laser‐flash photolysis studies with the solution of grafted film indicate the opening of the double bond of VCZ, which leads to the grafting. On the basis of the observed results, the mechanism of grafting in the system was proposed. © 1994 John Wiley & Sons, Inc.
Iodine binding by amylopectin and stability of the amylopectin–iodine complex
Authors: Davis Heather , Skrzypek Walter , Khan Arshad
Published: April 2003

The iodine binding capacity (IBC) of amylopectin (AP, from potatoes) is determined to be around 0.38% (w/w) of the total AP in the solution. The mass of iodine bound comprises about 13.6% of the mass of AP involved with the complex, suggesting that with every four iodine atoms bound there are 23 anhydroglucose residues (AGU). Since our previous study indicates that four iodine atoms within the helix of 11 AGUs form a chromophore unit in the API complex, only 48% of the AGUs (11 out of 23) in the AP molecule are directly involved with the iodine. The heat of reaction for the API complex formation is determined to be around −47 kJ/mol of I–I units bound and is significantly lower in magnitude than that of the amylose‐iodine (AI) complex [Biopolymers, 31, 57 (1991)]. A possible mechanism has been proposed for the formation of AI and API complexes with fixed compositions. © 1994 John Wiley & Sons, Inc.
Analysis of PPMMA films from oxygen plasma using X‐ray photoelectron spectroscopy
Authors: Kuruvilla Beena Annie , Zambre Madhukar , Gosavi Suresh , Gorwadkar Sucheta , Datta A. , Gangal S. A. , Kulkarni S. K.
Published: April 2003

Plasma polymerized methyl methacrylate (PPMMA) films have been synthesised on silicon substrates in RF glow discharge using oxygen plasma. The electron beam delineation sensitivity of the PPMMA films has been studied systematically by varying oxygen and monomer flow rates. X‐ray photoelectron spectroscopy (XPS) analysis clearly illustrates how C/O ratio in the films determines the properties of PPMMA films as electron beam resist. © 1994 John Wiley & Sons, Inc.
Characterization of chloroprene and maleic anhydride copolymer by 13C‐NMR spectroscopy and pyrolysis GC/MS
Authors: Cho Won‐Jei , Choi Chi‐Hoon , Ha Chang‐Sik
Published: April 2003

The radical copolymerizations of chloroprene (CP) and maleic anhydride (MAH) were carried out with AIBN in 1,4‐dioxane at 60°C. The monomer reactivity ratios were estimated as r1 (CP) = 0.38 and r2 (MAH) = 0.07. Microstructures in the copolymer of chloroprene (CP) and maleic anhydride (MAH) were investigated by 75.4 MHz 13C‐and 300 MHz 1H‐NMR spectroscopies. Resonances were assigned to the monomer sequence dyads CC, CM, and MC (C = chloroprene, M = maleic anhydride). Well resolved fine structure in the 13C‐NMR spectra showed that 1,2‐ and 3,4‐structural chloroprene units were negligible in the copolymer. The pyrolysis characterization of the copolymer was also investigated by the pyrolysis gas chromatography mass spectrometry (GC/MS). The fragments of CP and MAH monomers and CP‐MAH hybrid dimer, CO, and CO2 were identified after pyrolysis of the copolymer. © 1994 John Wiley & Sons, Inc.
Hydrocarbon dispersions of acrylic microspheres with polar surface functionality
Authors: Lee Ki‐Change , Winnik Mitchell A. , Jao Tze‐Chi
Published: April 2003

Submicron and micron sized particles containing a crosslinked core and a polar shell were prepared by 3‐stage nonaqueous dispersion [NAD] polymerization in an aliphatic hydrocarbon medium. When a poly (12‐hydroxystearic acid) [PHS] comb stabilizer was used in all three stages, the particles produced were spherical, submicron in size, and had a relatively broad size distribution. If the monomer mixture in the third stage contained relatively large amounts of butyl acrylate, stable dispersions of sponge‐like aggregates, 3–5 μm in size, were obtained. When butyl rubber was employed as a stabilizer precursor in the seed formation step, the shape of the final particles depended upon whether a crosslinker was employed in the second stage polymerization. When a crosslinker was present, the second‐stage particles and the subsequent third‐stage particles had a shrunken, raisin‐like appearance. When no crosslinker was present, spherical particles were obtained. In both cases, the resulting third‐stage particles were easily dispersed in water containing a small amount of amine base, indicating that COOH and OH groups are located at the surface (or in a shell at the surface) in these NAD particles. © 1994 John Wiley & Sons, Inc.
Temperature effect on conducting polyaniline salts: Thermal and spectral studies
Authors: Palaniappan S. , Narayana B. H.
Published: April 2003

Five different polyaniline salts have been prepared by chemical polymerization of aniline in aqueous solution of different acids. Polyaniline samples have been heat treated at four different temperatures (150, 200, 275, and 375°C) and characterized by electron paramagnetic, electronic absorption, and infrared spectral measurements. Thermal stabilities of the chemically synthesized polyaniline salts have been studied by thermal analysis and spectral methods. Polyaniline salts undergo a three‐step weight‐loss process in the heating cycle. The first step (up to 110°C) corresponds to the loss of water molecules from the polymer chain. In the second step (110–275°C), a small amount of acid escapes as volatile gas, and after 275°C the polymer undergoes oxidative thermal degradation in the third step. It was found that thermal stability of polyaniline salts depends on the counteranion used and the polymer is apparently stable up to 250°C. No structural changes have taken place up to 200°C and this has been confirmed from infrared and electronic absorption spectra. No definite correlation exists between conductivity and spin concentration. © 1994 John Wiley & Sons, Inc.
Thermoreversible reaction of diels—alder polymer composed of difurufuryladipate with bismaleimidodiphenylmethane
Authors: Kuramoto Noriyuki , Hayashi Keiji , Nagai Katsutoshi
Published: April 2003

Thermoreversible reaction of Diels‐Alder polymer composed of difurufuryladipate with bismaleimidodiphenylmethane was studied in dimethylformamide solution. The retro‐Diels‐Alder degradation occurred gradually at 90°C and Diels–Alder polymerization proceeded quickly at 60°C. © 1994 John Wiley & Sons, Inc.
Synthesis of end‐functionalized polystyrenes with organosilicon end‐capping reagents via living cationic polymerization
Authors: Miyashita Kazuaki , Kamigaito Masami , Sawamoto Mitsuo , Higashimura Toshinobu
Published: April 2003

The end‐functionalization of living polymers with bases (methanol, benzylamine, diethyl sodiomalonate, and sodium methoxide) and organosilicon compounds [X  Si(CH3)3;X : CH2C(CH3)COO, CH3COO, CH2CHCH2, C6H5] was investigated in the living cationic polymerization of styrene initiated with the 1‐phenylethyl chloride/SnCl4/nBu4NCl system in CH2Cl2 at −15°C. The four bases and C6H5SiMe3, independent of their structures, were apparently incapable of reacting with the living end and invariably led to polystyrenes with the ω‐end chlorine [∼ ∼ ∼ CH2CH(Ph)Cl] originated from the initiating system. The number‐average end‐functionality (F̄n) of the chloride, determined by 1H‐NMR, was close to unity (F̄n > 0.9). The presence of chlorine in the polymer was also confirmed by elemental analysis. In contrast, the quenching by the trimethylsilyl compounds with X = methacryloxy, acetoxy, and allyl gave ω‐end‐functionalized polystyrenes with the corresponding terminal groups (X) for which the F̄n values were close to unity (F̄n > 0.9). The effects of the structure of silyl compounds on end‐capping are also discussed. © 1994 John Wiley & Sons, Inc.
Synthesis and kinetics of polymerization of unsaturated monomers with OH groups in their structure: I.3‐hydroxyneopentyl acrylate
Authors: Iglesias M. T. , Guzmán J. , Riande E.
Published: April 2003

The synthesis of new unsaturated monomers containing functional groups has been theoretically analyzed by considering a simple kinetic scheme. In the reactions between acetyl and acryloyl chloride with neopentylglycol, it was shown that the comparison between theoretical and experimental results, does not allow us to conclude that the two rate constants controlling the reactions are equivalent. Kinetic experiments of the polymerization of 3‐hydroxyneopentyl acrylate were carried out in benzene and 1,4‐dioxane solution at different temperatures. Dilatometric techniques and nonlinear least‐squares methods were used to obtain kinetic data and to determine the kinetic constants, respectively. The values of \documentclass{article}\pagestyle{empty}\begin{document}$k_p /k_t^{1/2}$\end{document}
for this monomer were found higher in dioxane than in benzene due, probably, to the fact that in the last solvent the polymerization is heterogeneous. The activation energy, determined by using different values of \documentclass{article}\pagestyle{empty}\begin{document}$k_p /k_t^{1/2}$\end{document}
was found 7.6 kcal/mol.
The stereostructure of the polymers derived from 3‐hydroxyneopentyl acrylate and 3‐acetoxyneopentyl acrylate was determined by 13C‐NMR spectroscopy from the analysis of the resonance signals belonging to the carbonyl groups, obtaining values for the fraction of isotactic dyads in the range 0.36 ± 0.03 for both polymers. Finally, the glass transition temperatures of both polymers, determined calorimetrically, were found 281 and 255 K, respectively. © 1994 John Wiley & Sons, Inc.
Molecular composite. II. Novel block copolymer and semi‐interpenetrating polymer network of rigid polyamide and flexible polyimide
Authors: Chang Ken‐Yuan , Chang Hurng‐Ming , Lee Yu‐Der
Published: April 2003

2,2'‐Dimethyl‐4,4'‐diamino‐biphenyl was used to prepare a lyotropic amine‐terminated polyamide (PBTA) prepolymer with terephthaloyl dichloride, and an amide oligomer with reactive endcaps of maleimide, respectively. The former was employed in an attempt to increase the solubility of PA/PI block copolymers, and the latter to produce a three‐dimensional (isotropic) reinforced molecular composite through the technology of a semiinterpenetrating polymer network (semi‐IPN). PBTA prepolymer was copolymerized with an amine‐terminated polyimide via a coupling reaction using terephthaloyl dichloride. The resultant block copolymers were characterized by IR, NMR, ηinh and GPC to confirm that the copolymerization reaction was precisely accomplished, as well as to determine their composition and molecular weight. Thermal analysis and lyotropic behavior were also studied for these copolymers. Rigid‐rod amide oligomer was crosslinked in the presence of another flexible polyimide. Five sets of semi‐IPN films were prepared under varying compositions. The curing conditions were investigated by DSC; in addition, the cured semi‐IPNs exhibited a single phase (1 Tg) according to examination by an instrument for thermally stimulated current (TSC). No large‐scale phase separation was observed in SEM images of the fractured surfaces. © 1994 John Wiley & Sons, Inc.
Fullerenated carbazole polymers via bromination
Authors: Thomas Rhys N.
Published: April 2003

Surface‐substituted and homogeneous fullerenated polymers were produced by bromination followed by a Friedel‐Crafts reaction. Control over bonding patterns was provided by the bromination, which enabled the production of photodegradation‐resistant fullerenated polymers. © 1994 John Wiley & Sons, Inc.
Asymmetric zirconocene precursors for catalysis of propylene polymerization
Authors: Fierro Ricardo , Chien James C. W. , Rausch Marvin D.
Published: April 2003

Racemic isopropylidene (1‐η5‐cyclopentadienyl)(1‐η5‐indenyl) dichlorozirconium and the 3‐methylindenyl derivative have been synthesized and characterized. These precursors activated with methylaluminoxane produce poly(propylene) with hemiisotactic microstructures. © 1994 John Wiley & Sons, Inc.
New results of the free radical ring‐opening polymerization
Authors: Letsch Jörg , Klemm Elisabeth
Published: April 2003

The reaction of 5‐ring ketene‐O, N‐acetals with peroxides was investigated. It was shown that benzoyl peroxide adds to monomers 5a and 5b by ring opening, giving the corresponding linear diester amides 6a and 6b, respectively. The ketene‐O,N‐acetal 5c adds benzoyl peroxide, without ring opening, by addition to the exomethylene group, giving the cyclic‐O,N‐acetal diester 6c. With phthaloyl peroxide cyclic esteramides 7 and oligomeric products are formed. The chemical structures of the addition products were confirmed by NMR spectra and elemental analysis. © 1994 John Wiley & Sons, Inc.