bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of AB(BA), ABA and BAB block copolymers of tert‐butyl methacrylate (A) and ethylene oxide (B)
Authors: Wang Jinshan , Varshney Sunil Kumar , Jerome Robert , Teyssie Philippe
Published: April 2003

Well‐defined AB(BA), ABA, and BAB block copolymers of tert‐butyl methacrylate (tBMA) (A) and ethylene oxide (EO) (B) have been prepared by sequential living anionic polymerization of the two comonomers, irrespective of their addition order. Diphenyl methyl potassium and naphthalene potassium have been successfully used as mono‐ and difunctional initiators, respectively. In all cases, molecular weight and composition of the block copolymers can be predicted on the basis of the monomer over initiator molar ratio, and the molecular weight distribution is relatively narrow. Size exclusion chromatography, selective extractions of homopolymers, and 1H‐ and 13C‐NMR spectroscopy support that block copolymerization proceeds without homopolymer formation nor side reactions, e.g., transesterification reactions. The PtBMA blocks have been quantitatively hydrolyzed into polyacid ones with formation of polyacid‐b‐polyether block copolymers as supported by titration, 1H‐NMR, and IR analysis. © 1992 John Wiley & Sons, Inc.
Novel cyano‐containing copolymers of vinyl esters for piezoelectric materials
Authors: Hall H. K. , Padias Anne Buyle , Chu Guobei , Lee Hee‐Yeon , Kalnin Ilmar , Sansone Michael , Breckenridge George
Published: April 2003

The synthesis of a series of novel cyano‐containing copolymers is described. Alternating copolymers of acrylonitrile with vinyl esters are obtained by increasing the electrophilic character of the nitrile monomers by complexation with zinc chloride. Copolymers of methyl and ethyl α‐cyanoacrylates with vinyl esters are prepared using radical initiators in the presence of 7% acetic acid as inhibitor for anionic polymerization. The copolymers of methyl α‐cyanoacrylate with the vinyl esters have Tg's above 140°C. Methyl vinylidene cyanide (MVCN) copolymerizes spontaneously with para‐substituted styrenes to yield copolymers with high inherent viscosities and high Tg (160°C) and the copolymer of MVCN with vinyl acetate is also synthesized. The pyroelectric constants p for these polymers were measured and the values of p for the copolymers of vinyl acetate with methyl β,β‐dicyanoacrylate, methyl α‐cyanoacrylate, or MVCN were in the same range as the well‐studied vinylidene cyanide/vinyl acetate copolymer. A higher concentration of dipoles generally results in higher Tg's and higher pyroelectric coefficients. © 1992 John Wiley & Sons, Inc.
Carbonation of polymeric organolithium compounds: Effects of chain end structure
Authors: Quirk Roderic P. , Yin Jian
Published: April 2003

The carbonation of the adduct of poly(styryl)lithium with 1,1‐diphenylethylene with gaseous carbon dioxide in benzene proceeds in high yield (>99%) compared to the inefficient functionalizations for poly(styryl)lithium (66%), poly(isoprenyl)lithium (59%), and polybutadienyl)lithium (27%). The quantitative carboxylation of poly(isoprenyl)lithium and poly(butadienyl)lithium requires the presence of larger amounts of Lewis bases such as THF ([THF]/[Li] = 300) or TMEDA ([TMEDA]/[Li] = 46) compared to poly(styryl)lithium in which a ratio of [TMEDA]/[Li] = 12 is effective. © 1992 John Wiley & Sons, Inc.
Thermal degradation of polymethacrylic acid
Authors: Ho Bang‐Chein , Lee Yu‐Der , Chin Wei‐Kuo
Published: April 2003

The thermal degradation of polymethacrylic acid was found to have two separate decomposition regions. The first decomposition region, due to anhydride formation primarily, was caused by the conversion of polymethacrylic acid to polymethacrylic anhydride. This reaction followed first‐order kinetics and had an activation energy of 40.5 kcal/mol. The second decomposition region was the thermal degradation for the corresponding polymethacrylic anhydride. In this region, the fragmentation of anhydride rings structure in polymethacrylic anhydride constitutes the major decomposition reaction with an activation energy of 37.4 kcal/mol. © 1992 John Wiley & Sons, Inc.
Synthesis of thermally‐induced phase separating polymer with well‐defined polymer structure by living cationic polymerization. I. Synthesis of poly(vinyl ether)s with oxyethylene units in the pendant and its phase separation behavior in aqueous solution
Authors: Aoshima Sadahito , Oda Hiroshi , Kobayashi Eiichi
Published: April 2003

Living cationic polymerization of alkoxyethyl vinyl ether [CH2CHOCH2CH2OR; R: CH3 (MOVE), C2H5 (EOVE)] and related vinyl ethers with oxyethylene units in the pendant was achieved by 1‐(isobutoxy)ethyl acetate (1)/Et1.5AlCl1.5 initiating system in the presence of an added base (ethyl acetate or THF) in toluene at 0°C. The polymers had a very narrow molecular weight distribution (M̄w/M̄n = 1.1–1.2) and the M̄n proportionally increased with the progress of the polymerization reaction. On the other hand, the polymerization by 1/EtAlCl2 initiating system in the presence of ethyl acetate, which produces living polymer of isobutyl vinyl ether, yielded the nonliving polymer. When an aqueous solution of the polymers thus obtained was heated, the phase separation phenomenon was clearly observed in each polymer at a definite critical temperature (Tps). For example, Tps was 70°C for poly(MOVE), and 20°C for poly(EOVE) (1 wt % aqueous solution, M̄n ∼ 2 × 104). The phase separation for each case was quite sensitive (ΔTps = 0.3–0.5°C) and reversible on heating and cooling. The Tps or ΔTps was clearly dependent not only on the structure of polymer side chains (oxyethylene chain length and ω‐alkyl group), but also on the molecular weight (M̄n = 5 × 103‐7 × 104) and its distribution. © 1992 John Wiley & Sons, Inc.
Substrate temperature effects on film chemistry in plasma depositions of organics. II. Polymerizable precursors
Authors: López Gabriel P. , Ratner Buddy D.
Published: April 2003

The influence of substrate temperature during plasma deposition on the chemistry of the organic films formed was examined. Plasma ionization of precursor gases that are polymerizable by conventional mechanisms was studied. Film chemistry was analyzed by x‐ray photoelectron spectroscopy (XPS). Monomers that polymerize by a free radical mechanism [2‐hydroxyethyl methacrylate (HEMA) and hexafluorobutadiene (HFB)] form more regular polymers (i.e. with less molecular rearrangement) by plasma deposition at low substrate temperatures than monomers that polymerize by ionic mechanisms [ethylene oxide (EO) and tetrahydrofuran (THF)]. In all cases, lowering the substrate temperature during deposition produces films with elemental composition virtually identical to that of the precursor gas. Comparison of high‐resolution XPS spectra of the deposited films with those for model polymers suggests that functional groups in the monomers used to generate the plasma are incorporated to a greater extent at low substrate temperatures. The effect of plasma power on the degree of precursor structure retention obtained when reduced substrate temperatures are employed was also examined. Plasma deposition of HEMA at low substrate temperatures and low plasma power produces thin films which are, by core level XPS, indistinguishable from HEMA polymerized by conventional methods. EO and THF films coated at low substrate temperatures on glass, polyethylene, or polytetrafluoroethylene varied widely in surface chemistry due to differences in film uniformity. Film quality (uniformity) is enhanced for these low reactivity precursors by pretreating substrates with an argon plasma. © 1992 John Wiley & Sons, Inc.
Preparation and characteristics of photocrosslinkable hydrophilic polymer having cinnamate moiety
Authors: Nakayama Yasuhide , Matsuda Takehisa
Published: April 2003

The reaction of copolymer of N,N‐dimethylacrylamide (DMAA) and bromoethyl methacrylate with potassium cinnamate produced water‐soluble photosensitive polymers. Photosensitive polyDMAA films were irradiated with a 400 W high‐pressure mercury lamp (λ > 280 nm) to produce crosslinked polymers, which were swollen in water. The degree of swelling was controlled by the irradiation time and content of cinnamate moieties in copolymers. Higher cinnamoylation and longer irradiation time resulted in higher yield of crosslinked polymers and less swellability. Partial degelation upon irradiation at λ ∼ 254 nm was observed. The advantage of gelation via photodimerization over conventional chemical crosslinking methods is discussed in conjunction with biomedical applications. © 1992 John Wiley & Sons, Inc.
Synthesis of aromatic polymers via palladium‐catalyzed cross‐coupling reactions with magnesium, zinc, and tin reagents: A comparison
Authors: Bochmann M. , Kelly K. , Lu J.
Published: April 2003

Difunctional magnesium, zinc, and tin reagents MC6H4OC6H4M (M = MgBr, ZnCl, SnBu3) in the presence of palladium or nickel catalysts undergo cross‐coupling polymerizations with aromatic, heteroaromatic, benzylic, and allylic dihalides to give oligomeric and polymeric materials. Tin reagents lead to products of higher molecular weight than Mg and Zn reagents. The reaction is sensitive to the solvent and enhanced by magnesium halides. Increased reaction temperatures lead only to moderate increases in the degree of polymerization and are limited by catalyst decomposition above 200°C. The new poly(ether ketone) and poly(ether sulfone) type polymers prepared show high thermal stability. In contrast to conventional poly(ether sulfones)s, the biphenyl‐based sulfone polymers reported here are crystalline. © 1992 John Wiley & Sons, Inc.
Determination of microstructure and glass‐transition temperature of acrylonitrile‐methyl acrylate copolymers by 13C‐NMR spectroscopy
Authors: Brar A. S. , Sunita
Published: April 2003

Acrylonitrile‐methyl acrylate (A/M) copolymers of different monomer compositions were prepared by bulk polymerization using free radical initiator (benzoyl peroxide). Copolymer compositions were determined by elemental analyses and comonomer reactivity ratios were determined by the nonlinear least squares errors‐in‐variables methods (EVM). Terminal and penultimate reactivity ratios have been calculated using the observed monomer triad sequence distribution determined from 13C{1H}‐NMR spectra. The triad sequence distribution was used to calculate diad concentrations, conditional probability parameters, number‐average sequence lengths, and run number in the copolymers. The observed triad sequence concentrations determined from 13C{1H}‐NMR spectrum agreed well with those calculated from reactivity ratios. Glass transition temperatures (Tg) of various copolymers determined from DSC gave good agreement with those obtained from NMR. © 1992 John Wiley & Sons, Inc.
Kinetics and steric limitation of quaternization of poly(4‐vinylpyridine) with mesogenic ω‐(4′‐methoxy‐4‐biphenylyloxy)alkyl bromides
Authors: Navarro‐Rodriguez Damaso , Frere Yves , Gramain Philippe
Published: April 2003

The kinetics and characteristics of the quaternization of poly(4‐vinylpyridine) with very large alkylating agents are studied with the main aim to demonstrate the occurrence of a limitation of the reaction due to steric effect. Kinetics are carried out in sulfolane at different temperatures with two ω‐(4'‐methoxy‐4‐biphenylyloxy)alkyl bromides. An important limitation of the reaction is demonstrated: 30% of the pyridine groups are inaccessible at 333 K, 23% at 355.5 K, and 4% at 363 K. Post‐quaternization experiments with butyl bromide of already partially quaternized P4VP also demonstrate this limitation. The occurrence of global steric hindrance and hydrophobic effects affecting the conformation of the chain in solution is proposed to explain the limited accessibility of the pyridine groups. The results question the classical neighboring group model generally used to describe the slowing down of the quaternization reaction with increasing quaternization ratio. The thermal stability of the quaternized polymers and the colors of the reaction medium are also discussed. © 1992 John Wiley & Sons, Inc.
Metallocene catalysts for olefin polymerizations. XXIV. Stereoblock propylene polymerization catalyzed by rac‐[anti‐ethylidene(1‐η5‐tetramethylcyclopentadienyl)(1‐η5‐indenyl)dimethyltitanium: A two‐state propagation
Authors: Chien James C. W. , Llinas Geraldo Hidalgo , Rausch Marvin D. , Lin Ye‐Gang , Winter H. Henning , Atwood Jerry L. , Bott Simon G.
Published: April 2003

Racemic‐anti‐[ethylidene(1‐η5‐tetramethylcyclopentadienyl) (1‐η5‐indenyl)dimethyltitanium (6) has been synthesized and its molecular structure determined by x‐ray diffraction methods. The two TiMe(1) and TiMe(2) units have bond distances differing by 0.08 Å and their proton NMR resonances are separated by over 1 ppm. Using this compound and methylaluminoxane (MAO) as the activator, at 25°C the 6/MAO catalyst produced polypropylene having crystalline domain with physical crosslinks. The polymers obtained at lower polymerization temperatures are rheologically liquids. The behaviors of this catalyst system resembles closely the previously reported rac‐[anti‐ethylidene(1‐η5‐tetramethylcyclopentadienyl) (1‐η5‐indenyl)dichlorotitanium (4)/MAO system. The structure of 6 determined here furnishes tangible support for the proposed two‐state (isomeric)‐switching propagation mechanism. Addition of MAO to 6 causes broadening of the Me(1) resonance in the 1H‐NMR spectra, and 6 is decomposed by Ph3C+B(C6F5)‐4. © 1992 John Wiley & Sons, Inc.
Emulsion polymerization of vinyl acetate using a polymerizable surfactant. I. Kinetic studies
Authors: Urquiola M. B. , Dimonie V. L. , Sudol E. D. , El‐Aasser M. S.
Published: April 2003

A polymerizable surfactant, sodium dodecyl allyl sulfosuccinate (TREM LF‐40; Henkel) and its nonpolymerizable counterpart were used in comparative studies of the emulsion polymerization of vinyl acetate. The conversion‐time behavior differed for the two surfactants; the TREM LF‐40 showed a decrease in the polymerization rate with increasing concentration while its hydrogenated derivative showed the opposite behavior, the rate increasing with increasing surfactant. Particle size analysis revealed a decreasing particle size with increasing surfactant concentration for both series of reactions. An explanation for the seemingly ambiguous results obtained for the polymerizable surfactant was sought by examining the reactivity of its vinyl group in copolymerization with vinyl acetate and its allylic group in a chain transfer reaction. The results suggest that both the copolymerization and chain transfer reactions can lead to the observed reduction in polymerization rate with increasing TREM LF‐40 concentration. © 1992 John Wiley & Sons, Inc.
Polymerization of propargylamine and 1,1‐diethylpropargylamine by transition metal catalysts
Authors: Gal Yeong‐Soon , Jung Bal , Lee Won‐Chul , Choi Sam‐kwon
Published: April 2003

Some polyacetylene derivatives containing an amine functional group were prepared by the polymerization of propargylamine (PA) and 1,1‐diethylpropargylamine (DEPA) with various transition metal catalysts. In the polymerization of PA, Mo‐based catalysts were more effective than that of W‐based catalysts, and organoaluminum compounds, especially EtAlCl2, were found to be very effective cocatalysts. In the polymerization of DEPA, Mo‐and W‐based catalyst systems showed a similar catalytic activity. The polymerization easily proceeded in polar solvents such as nitrobenzene and DMF as well as nonpolar aromatic solvents such as chlorobenzene, toluene, etc. The resulting poly(PA) and poly(DEPA) were insoluble in organic solvents regardless of polymerization catalysts but the polymers were found to be stable to air oxidation. Thermogravimetric analyses and thermal transitions of poly(PA) and poly(DEPA) were also studied. © 1992 John Wiley & Sons, Inc.
Palladium catalyzed ethylene‐carbon monoxide alternating copolymerization
Authors: Zhao Allen X. , Chien James C. W.
Published: April 2003

A new [(PPh2CH2CH2CH2PPh2)Pd(CH3CN)2](BF4)2/CH3OH catalyst for olefin/carbon monoxide alternating copolymerization has been found which is far more active and more stable than previous monodente phosphine Pd catalysts. Methanol is a coinitiator as well as a chain transfer agent. Protonic acid is not a coinitiator but causes chain transfers. In the absence of methanol, the copolymerization was characterized by long induction period and slow rate © 1992 John Wiley & Sons, Inc.
The synthesis and characterization of a poly(maleimide‐ether) containing pendent thiophene rings
Authors: Edge Stephen , Charlton Adam , Varma Karikath S. , Underhill Allan E. , Hansen Thomas K. , Becher Jan , Kathirgamanathan Poopathy , Khosravi Ezat
Published: April 2003

The preparation of a poly(maleimide‐ether) containing pendent thiophene rings via the reaction of 2‐(3‐thienylmethyl)‐1,3‐N,N'‐bis(3,4‐dichloromaleimido) propane with 1,4‐dihydroxybenzene is described. The novel 2‐substituted‐1,3‐N,N'‐bis(3,4‐dichloromaleimido) propanes were obtained by allowing their corresponding diamine hydrochlorides to react with 3,4‐dichloromaleic anhydride in acetic acid in the presence of sodium methoxide. The diamine hydrochlorides were prepared by the reduction of their respective diamides. The poly(maleimide‐ether)s were fully characterized and 13C‐NMR spectroscopy was used to confirm the microstructure of the materials. The properties of the thiophene substituted polymer are compared with model poly(maleimide‐ether)s. Electrochemical studies indicated that the thiophene rings in the thiophene‐substituted poly(maleimide‐ether) were not electroactive. © 1992 John Wiley & Sons, Inc.
Metalloporphyrins catalyze polyene‐polymers to polyepoxides
Authors: Tornaritis M. J. , Coutsolelos A. G.
Published: April 2003

Polyene polymers [natural rubber (cis‐polyisoprene), trans‐polyisoprene, and cis‐polybutadiene] were transformed to the corresponding polyepoxides which are a polyalcohol and soap precursor. The catalysts used were chloro‐ or acetato‐manganese(III) tetraphenylporphyrin [MnIII(TPP)Cl or MnIII(TPP)OAc] in association with two different oxygen donors, sodium hypochloride and iodosylbenzene (Por, unspecified porphyrinato ligand; TPP, 5,10,15,20‐tetraphenylporphyrinato ligand). This transformation in either biphasic system, H2O(aqua)‐CH2Cl2 or PhIO(solid)‐CH2Cl2, was monitored by 1H‐NMR and IR spectroscopy. In both cases the transformation to the polyepoxide was completed within a few hours. © 1992 John Wiley & Sons, Inc.
Resist system based on the cationic photocrosslinking of poly(4‐hydroxystyrene) and polyfunctional electrophiles
Authors: Fahey J. T. , Shimizu K. , Fréchet J. M. J. , Clecak N. , Willson C. G.
Published: April 2003

New resist systems based on acid‐catalyzed, electrophilic aromatic substitution are described. These new resists show high sensitivity to deep UV and E‐beam radiation with values approaching 2 mJ/cm2and 2 μC/cm2, respectively. The resists are based on a three component system consisting of poly(4‐hydroxystyrene), a polyfunctional, low molecular weight, latent electrophile, and a photoactive onium salt used as an acid generator. Irradiation of the resist film produces a latent image of acid dispersed in the matrix. During the postbaking step the photo‐generated acid reacts with the latent polyfunctional electrophile and releases a reactive carbocationic intermediate with concomitant liberation of acetic acid. The carbocationic intermediate then reacts with neighboring phenolic moieties in a crosslinking reaction. The substitution reaction liberates a proton, making the process catalytic in nature, thus incorporating the concept of chemical amplification. These highly sensitive materials can be used as nonswelling negative multipurpose resists that function in deep‐UV, x‐ray or E‐beam modes. © 1993 John Wiley & Sons, Inc.
Studies on the thermotropic liquid crystalline polymer. VII. Synthesis and properties of photocrosslinkable poly(ether‐ester) containing cinnamic group
Authors: Li Chen‐Hui , Lai Wen‐Wei , Hsu Keh Ying , Chang Teh‐Chou
Published: April 2003

A series of semi‐aromatic poly(ether‐ester)s containing cinnamic group was prepared from 4,4′‐diacrylic acid‐α,ω‐phenoxyalkanes with diols in the presence of diphenylchlorophosphate (DPCP) and pyridine as a catalyst and solvent. The phase behavior of these polymers was studied by differential scanning calorimetry (DSC), optical polarizing microscopy equipped with a heating stage, and wide‐angle x‐ray diffraction (WAXD). All of the poly(ether‐ester)s, except P3, show nematic or smectic thermotropic liquid crystalline behaviour under optical polarizing microscopic observation. These polymers can undergo photocrosslinking reaction upon heating, as examined by IR, solubility, and DSC analysis. © 1993 John Wiley & Sons, Inc.
Synthesis of triphenylsilyl‐ and triphenylmethyl‐telechelic polyisobutylene: An approach to the synthesis of multi‐ion telechelic ionomers
Authors: Storey Robson F. , Lee Youngkwan
Published: April 2003

Triphenylsilyl‐ and triphenylmethyl‐telechelic polyisobutylene (PIB) were prepared by lithiation of three‐arm star PIBs carrying either olefinic or tert‐alkyl chloride end groups, followed by reaction with triphenylsilyl chloride or triphenylcarbenium ion, respectively. Since the lithiated intermediate is a substituted allylic carbanion, the chain end also possesses a double bond which is located β‐γ relative to the silyl or triphenylmethyl group. The phenyl groups were incorporated into the polymers to provide extra sites for sulfonation, in addition to the double bond, to enable the synthesis of multi‐ion telechelic ionomers. 1H‐ and 13C‐NMR spectroscopy showed that triphenylsilylation and triphenylmethylation were essentially quantitative when applied under the prescribed conditions to either the model compound, 2,4,4‐trimethyl‐1‐pentene, or to the telechelic PIBs. It was observed that exhaustive sulfonation of these materials using acetyl sulfate or chlorosulfonic acid yielded only about 50% sulfonation of the available sites. This suggests that sulfonation of closely adjacent, multiple sites within the same molecule fails due to deactivation of the remaining sites after one or perhaps two sulfonations. However, the triphenylsilyl‐ and triphenylmethyl‐telechelic PIBs represent novel prepolymers which can perhaps be derivatized by some method other than sulfonation, and the general concept for producing telechelic ionomer precursors with multiple sulfonation sites may prove successful with other moieties containing spacer groups between sites. © 1993 John Wiley & Sons, Inc.
Kinetics of radical polymerization of dimethylphenyl methacrylates
Authors: Vrhovac Ljubica , Djurasović Nebojs̃a , veličković Jovan
Published: April 2003

The kinetics of free radical polymerization of all six existing isomeric dimethylphenyl methacrylates were studied in bulk at 60°C, initiated by dilauroyl peroxide, using dilatometry. The different polymerization rates observed, resulting from the different monomer structures, are discussed in terms of steric and other effects, considering also the previous results for tolyl methacrylates. © 1993 John Wiley & Sons, Inc.
Functional polymers for colloidal applications. V. Novel behavior of polymeric emulsifiers in emulsion polymerization
Authors: Kuo Ping‐Lin , Chen Chaur‐Jinn
Published: April 2003

The polymeric emulsifier poly(dodecyl acrylate‐co‐acrylic acid) [i.e., the sodium salt (PDA)] and monomeric emulsifier sodium dodecyl glutarate (SDG) have been synthesized. PDA and SDG are used as emulsifiers in the emulsion polymerization of styrene with both the water‐soluble initiator potassium persulfate (K2S2O8) and the oil‐soluble initiator 2,2′‐azobisisobutyronitrile (AIBN). The PDA/K2S2O8 system showed a bimodel distribution of particle sizes (2 and 0.05 μm). A bimodel particle distribution was also found for the PDA/AIBN system, but the distribution for the large particles was wide (0.1–10 and 0.07 μm). The SDG/K2S2O8 system displayed only one kind of particle size (0.05 μm), but the SDG/AIBN system also showed a bimodel distribution of particle sizes (0.05 and 5 μm). These bimodel distribution results for the PDA/K2S2O8, PDA/AIBN, and SDG/AIBN systems indicate that the polymerization sites are both in oil droplets and in micelles (polymer aggregates). This mechanism is interpreted in terms of the formation of polymer aggregates, which is supported by the results of pyrene solubilization, pyrene fluorescence, surface tension, and pyrene excimer experiments. © 1993 John Wiley & Sons, Inc.
Synthesis and emulsion copolymerization of amphiphilic poly(2‐oxazoline) macromonomer possessing a vinyl ester group
Authors: Uyama Hiroshi , Honda Yoichiro , Kobayashi Shiro
Published: April 2003

The present article describes the synthesis and emulsion copolymerization of a block‐type amphiphilic poly(2‐oxazoline) macromonomer possessing a polymerizable vinyl ester group. The macromonomer was synthesized by one‐pot two‐stage block copolymerization of 2‐oxazolines using vinyl iodoacetate as initiator. 2‐Methyl‐ and 2‐n‐butyl‐2‐oxazolines were employed for the construction of hydrophilic and hydrophobic segments, respectively. The surface activities evaluated by the surface tension of the macromonomer in water were fairly good. Emulsion copolymerization of vinyl acetate with the macromonomer was carried out. The macromonomer acted as a polymeric surfactant, as well as a comonomer. The resulting copolymer latex particles were spherical and their diameter was in the sub‐micron range. The effects of the composition of the macromonomer on the emulsion copolymerization and the resulting latex particles were examined. © 1993 John Wiley & Sons, Inc.
Anionic copolymerization of 2,3,4,5,6‐pentafluorostyrene and divinylbenzene
Authors: Nishimura Shin , Nagai Akira , Takahashi Akio , Narita Tadashi
Published: April 2003

Anionic copolymerizations of 2,3,4,5,6‐pentafluorostyrene (PFS) with 1,3‐divinylbenzene (m‐DVB) and 1,4‐divinylbenzene (p‐DVB) were performed by using lithium diisopropylamide as an initiator in order to synthesize the fluorine‐containing linear polymer with pendant vinyl groups. The products were soluble copolymers possessing both PFS and DVB monomeric units, and the DVB monomeric unit in copolymer had pendant vinyl group. This copolymerization reaction took a much longer time than that of styrene with DVB. The copolymerization parameter of this system was examined from copolymer composition curves. In this system, m‐DVB was found to be more reactive than p‐DVB. The reactivity of copolymerization was largely influenced by the reactivity of active species. © 1993 John Wiley & Sons, Inc.
Water penetration in nylon 6,6: Absorption, desorption, and exchange studied by NMR microscopy
Authors: Fyfe Colin A. , Randall Leslie H. , Burlinson Nick E.
Published: April 2003

The uptake of water by nylon 6,6 [42DB Adipure (trade name of Dupont Canada Inc.)] at 100°C has been monitored by a combination of one‐dimensional proton NMR spectroscopy, relaxation time (T1 and T2) measurements and proton microscopic NMR imaging techniques. The relaxation times of the water absorbed into the nylon matrix are very short at room temperature, (T2 < 1 ms and T1 ≈ 1 s) indicating that the water is located in a highly restricted environment and suggesting that strong interactions exist between the absorbed water and the polymer. The diffusion profiles measured at room temperature indicate that the diffusion of water into nylon 6,6 at 100°C is Case I Fickian diffusion. The spatial dependence of the T2 relaxation time constant and its variation with the water content was also examined. The results reveal that both T2 and T2* decrease toward the center of the sample in samples that have a concentration gradient of sorbed water. In fully saturated samples, no spatial dependence was observed. The overall values of T2 and T2* are also observed to increase as a function of exposure time. An evaluation of the desorption process at room temperature and at 100°C was performed. A continuous, exponentially decreasing solvent profile was observed for the desorption process which again indicates Case I Fickian kinetics. The exchange process of external bulk and atmospheric water with deuterium oxide (D2O) saturated nylon rods has also been studied using the microscopic imaging technique. © 1993 John Wiley & Sons, Inc.
Cyclopolymerization. XIX. Effect of N‐substituents on cyclopolymerizability of N‐allylmethacrylamides
Authors: Kodaira Toshiyuki , Okumura Miyuki , Urushisaki Michio , Isa Kimio
Published: April 2003

The effect of bulky N‐substitutents of N‐t‐butyl‐ and N‐phenyl‐N‐allylmethacrylamides (BAMA and PAMA, respectively) on their cyclopolymerizability was investigated. BAMA yielded an almost completely cyclized polymer while the degree of cyclization of poly (PAMA) was about 95%. The latter value indicates that the effect of phenyl group is comparable with that of methyl group, since N‐methyl‐N‐allylmethacrylamide was reported to give a polymer with a degree of cyclization of 93%. Structural investigation on telomerization products of BAMA and PAMA permitted the assignment of the repeating cyclic units of these polymers to that of a five‐membered ring. This structural characteristic was also supported by the observation of five‐membered cyclized radicals on ESR measurements of these monomers. Rotation around amide CN bonds of these monomers and related compounds studied by 13C‐NMR was found to be strongly dependent on N‐substitutents. The mechanism of the cyclization was discussed in terms of the structure of the ring formed and rotation around amide CN bonds of these monomers. The reactivity of the methacryloyl and allyl groups involved in these monomers were compared based on the information obtained by structural investigation of polymers and telomerization products and by ESR studies. © 1993 John Wiley & Sons, Inc.
Crosslinked liquid crystal polymers from liquid crystal monomers: Synthesis and mechanical properties
Authors: Litt Morton H. , Whang Wha‐Tzong , Yen Kung‐Ti , Qian Xue‐Jun
Published: April 2003

Difunctional acrylates and methacrylate monomers have been made which are high order smectic liquid crystal (or crystalline) at room temperature. This report discusses materials with the following structure: F–S–M–S–F, where F is a functional group, acrylate or methacrylate (A or M); S is a spacer (CH2)n(n), and M is a mesogen—in this case 4,4′‐dioxybiphenyl (B). They are codified as BnA or BnM where n is the number of methylenes in the spacer. High conversion with high Tg can be obtained when polymerizing in the smectic state because the reactive end groups are concentrated in a small volume and can react well with little or no diffusion. B2A, B3A, B6A, B11A, and B3M were polymerized in the smectic state and compared to polymers made at temperatures where the monomers were isotropic. High conversion was obtained below final Tg—even then, probably because the polymers were ordered. All the polymers were studied by WAXD and dynamic mechanical spectroscopy. Solid‐state NMR on B3A showed that there was very high conversion of the double bonds at all temperatures. B3A photopolymerized in the smectic state (60–76°C) produced a crystalline polymer with Tg = 185°C (1 Hz). When photopolymerized at 85°C, above the isotropization temperature (Ti), a poorly organized polymer was obtained with a Tg of 155°C (1 Hz). Monomers with an odd number of methylene groups as spacers were crystalline after polymerization. With an even number of methylene groups, they lost most of their crystallinity on polymerization below Ti, but retained a low order smectic structure. Similar structures were obtained with all the monomers when they were polymerized above Ti. There was little effect of polymerization temperature on Tg when the spacers had an even number of methylene groups. © 1993 John Wiley & Sons, Inc.
Preparation of poly(4‐vinyl‐2‐hydroxypyridine) and its catalytic activity on mutarotation of 2,3,4,6‐tetramethyl‐α‐D‐glucose
Authors: Arai Kenichiro
Published: April 2003

Poly(4‐vinyl‐2‐hydroxypyridine), PVHP, was prepared by the reaction of poly(4‐vinylpyridine) with hydrogen peroxide in acetic acid, and subsequent refluxing in acetic anhydride at 150°C. Conversion of pyridine units to 2‐hydroxypyridine units was about 75% and the obtained product was a deep‐brown powder. Mutarotation rates of 2,3,4,6‐tetramethyl‐α‐D‐glucose, TMG, in chloroform and in ethanol in the presence of the PVHP were measured and compared with those in the presence of 2‐hydroxypyridine. The PVHP was found to show higher catalytic activities on the mutarotation than 2‐hydroxypyridine in both solvents, which was deduced to be due to more efficient formation of the complex between TMG and the catalyst molecules. The mutarotation rates were higher in chloroform than in ethanol for both catalysts, which suggests that the mutarotation in the presence of the catalyst is more favorable in the strongly hydrogen bonding solvent because of higher interaction between the substrate and the catalyst molecules. The mutarotation rates increased proportionally with increasing concentration of the substrate in both solvents and in the presence of both catalyst, while they increased but not proportionally with increasing concentration of the catalyst; the increase began to level‐off with increasing concentration of the catalyst. The latter tendency was assumed to result from the association of the catalyst units themselves, which makes efficiency of the complex formation between TMG and the catalyst molecules lower. © 1993 John Wiley & Sons, Inc.
Polymerization of ethylene using a high‐activity Ziegler–Natta catalyst. II. Molecular weight regulation
Authors: Marques Maria M. V. , Nunes Clemente Pedro , Tait Peter J. T. , Dias Alberto Romão
Published: April 2003

This article describes studies on the variables that regulate the molecular weight in ethylene polymerization using a highly active Ziegler–Natta catalyst with hydrogen for molecular weight control. The dependence of the degree of polymerization on the concentration of catalyst, cocatalyst, monomer, partial pressure of hydrogen, and temperature has been established. The rate constant for chain transfer with cocatalyst has been evaluated. © 1993 John Wiley & Sons, Inc.
Degradation of poly(methylphenylsilylene) and poly(di‐n‐hexylsilylene)
Authors: Kim Hwan Kyu , Matyjaszewski Krzysztof
Published: April 2003

Degradation of poly(methylphenylsiylene) and poly(di‐n‐hexylsilylene) was studied by chemical and mechanical methods at ambient and higher temperatures. Purely thermal degradation in solid state starts as a slow process at 150°C and provides soluble and insoluble products which include cyclosilanes as well as various siloxanes. Sonication at ambient temperatures leads to the mechanical degradation of high molecular weight polymers by homolytic cleavage induced by shear forces. No cyclics are formed under these conditions. Polysilanes in the presence of strong nucleophiles degrade exclusively to cyclic oligomers. Rate of this back‐biting chain reaction depends on substituents at silicon atom, alkali metal, solvents, and temperature. Electrophiles degrade polysilanes to various α,ω‐difunctional oligosilanes. © 1993 John Wiley & Sons, Inc.
Novel polycationic biocides: Synthesis and antibacterial activity of polymeric phosphonium salts
Authors: Kanazawa Akihiko , Ikeda Tomiki , Endo Takeshi
Published: April 2003

Various polymeric phosphonium salts and the corresponding low‐molecular‐weight model compounds were prepared and their antibacterial activities against Staphylococcus aureus and Escherichia coli were explored by the viable cell counting method in sterile distilled water. Antibacterial activity of the polymers was found to be higher than that of the corresponding model compounds, particularly against S. aureus. Furthermore, the polymeric phosphonium salt exhibited a higher activity by 2 orders of magnitude than the polymeric quaternary ammonium salt with the same structure except the cationic part. Compounds with the longest alkyl chain (octyl) studied were found to exhibit particularly high activity, and this finding may be ascribed to the contribution of the increased hydrophobicity of the compounds to the cidal activity. © 1993 John Wiley & Sons, Inc.
Approaches to novel AB heteroaromatic polyamides based on cyanoimidazoles
Authors: Thurber Ernest L. , Rasmussen Paul G.
Published: April 2003

We report the synthesis of several AB monomers based on 2‐amino‐4,5‐dicyanoimidazole. Polymerization of the monomers to poly(imidazoleamide)s, by several methods is described. Amino acids 2‐amino‐4‐cyano‐1‐methyl‐5‐imidazolecarboxylic acid and 2‐amino‐5‐cyano‐1‐methyl‐4‐imidazolecarboxylic acid were prepared by mono‐ethanolysis of 2‐amino‐4,5‐dicyanoimidazole followed by methylation of the 1‐nitrogen. The resulting regioisomeric mixture of ethyl esters was separated by fractional crystallization and hydrolyzed to the desired amino acids. The regioisomeric structure was determined by NOE studies of the decarboxylated amino acids. The corresponding acid chlorides were prepared with thionyl chloride and isolated as the HCl salts. Activated esters were prepared by reacting the acid chlorides with alcohols such as 1,1,1‐trifluoroethanol and 2‐chlorophenol. Model compounds were prepared by the acylation of aminocyanoimidazoles but yields were low. The low nucleophilicity of the aminocyanoimidazolecarboxylic acids was partially overcome by the use of the acylation catalyst 4‐dimethylaminopyridine (DMAP) and the activating agent silicon tetrachloride. The acid chlorides were polymerized in amide solvents such as hexamethyl phosphoramide with pyridine and DMAP. A copolyamide consisting of both regioisomers was prepared from a regioisomeric mixture of the acid chlorides. In addition, aminolysis of 2‐chlorophenyl 2‐amino‐4‐cyano‐1‐methyl‐5‐imidazolecarboxylate resulted in a low yield of poly(imidazoleamide). Poly(imidazoleamide)s were red to tan which suggest conjugation along the polymer backbone. The solubility of the polyamides varied from amide solvents to sulfuric acid depending on the regioisomeric structure and molecular weight. The molecular weight of the heteroaramids was in the range from 1500 to 4000 based on viscosity measurements in sulfuric acid. The poly(imidazoleamide)s were thermally stable in excess of 300°C under air and nitrogen atmosphere. © 1993 John Wiley & Sons, Inc.
Ethylene–vinyl acetate semi‐batch emulsion copolymerization: Experimental design and preliminary screening experiments
Authors: Scott P. J. , Penlidis A. , Rempel G. L.
Published: April 2003

Ethylene–vinyl acetate emulsion copolymers are useful materials for paint, adhesive, and coating applications. The kinetics of their production remain largely unstudied, probably due to the inherent difficulties associated with pressure polymerizations. Polymerizations at elevated pressures are in general more difficult to understand and control, and relatively more expensive since one has to consider the added cost of increased safety precautions. Reported here are the preliminary results of an extensive experimental investigation of the variables which govern the ethylene–vinyl acetate emulsion process. Two redox initiator systems have been identified as more suitable for the polymerization process. Two buffer systems, namely sodium acetate/acetic acid and potassium phosphate, have been used to effectively control pH. The addition of n‐hexane has offered an effective method of enhancing the ethylene content in the copolymer produced. Several other important variables including agitation/mixing and emulsifier type and concentration have been identified and are discussed. These screening experimental observations have aided in the selection of suitable design levels for future, more focused experimentation to quantify the effects of reaction variables on the latex and copolymer properties of interest. A review of the existing literature on ethylene–vinyl acetate copolymer properties and processes is also included. © 1993 John Wiley & Sons, Inc.
Photo‐thermal properties of poly(4‐tert‐butoxycarbonyloxystyrene) bearing imino sulfonate units
Authors: Shirai Masamitsu , Kinoshita Hirotaka , Tsunooka Masahiro
Published: April 2003

Copolymers of 4‐tert‐butoxycarbonyloxystyrene (BOS) and 9‐fluorenilideneimino p‐styrenesulfonate (FISS) were synthesized. FISS units in copolymers became p‐styrenesulfonic acid units upon ultraviolet irradiation. The irradiated copolymers thermally decomposed to poly(hydroxystyrene) by liberating tert‐butoxycarbonyl (BOC) units at temperatures where the unirradiated copolymers were stable. The thermal decomposition of the copolymers catalyzed by sulfonic acid formed photochemically was studied by thermogravimetry. The pseudo first‐order rate constant (k) and the activation energy for the acid catalyzed thermal decomposition of BOC units in copolymers were evaluated. The thermolysis of the irradiated copolymer system was compared with that of the irradiated blended system of poly(4‐tert‐butoxycarbonyloxystyrene) (PBOCST) and 9‐fluorenilideneimino p‐toluene‐sulfonate (FITS). © 1993 John Wiley & Sons, Inc.
Characterization of water‐soluble oligomers formed during the emulsion polymerization of styrene by means of isotachophoresis
Authors: Morrison Bradley R. , Maxwell Ian A. , Napper Donald H. , Gilbert Robert G. , Ammerdorffer Joop L. , German Anton L.
Published: April 2003

The concentrations and probable nature of charged oligomers formed by aqueous‐phase termination in the persulfate‐initiated emulsion polymerization of styrene were measured by isotachophoresis. Isotachophoresis has some advantages over other techniques (e.g., GPC, UV spectroscopy) in that it separates species according to their molecular weight, geometry, and charge. The charged water‐soluble oligomeric species were detected in experiments in which particles were nucleated in a surfactant‐free environment. Identification of the moieties present was made by comparison with model compounds. Evidence was found for bimolecular combination as a major mechanism of termination in the aqueous phase, although the possibility of disproportionation could not be ruled out. The species formed in the aqueous phase under saturated monomer conditions were found to be subject to further reaction towards the end of polymerization. The surface adsorption characteristics of the compounds formed were compared with those of known surfactants and showed good agreement with the assumptions in the model of Maxwell et. al. [Macromolecules, 24, 1629 (1991)] for initiator efficiencies in emulsion polymerization. The relatively large concentrations of nonradical aqueous–soluble oligomeric compounds demonstrate conclusively that initiator efficiencies are not 100%, as is often assumed in such systems. © 1993 John Wiley & Sons, Inc.
Squid chitin as a potential alternative chitin source: Deacetylation behavior and characteristic properties
Authors: Kurita Keisuke , Tomita Koji , Tada Tomoyoshi , Ishii Shigeru , Nishimura Shin‐Ichiro , Shimoda Kayo
Published: April 2003

β‐Chitin was isolated from squid pens, and the characteristic chemical and physical properties were elucidated in comparison with those of shrimp chitin, α‐chitin. Deacetylation behavior of the squid chitin was first studied to look into the reactivity of β‐chitin and also to establish an efficient procedure for preparing squid chitosan. The squid chitin proved to show much higher reactivity in alkaline deacetylation than shrimp chitin. Although it was deacetylated quite easily, the product assumed a dark brown color under the ordinary reaction conditions for shrimp chitosan. Squid chitosan was successfully prepared by repeated alkaline treatments under mild conditions, particularly with high concentration alkali at low temperatures, without appreciable discoloration. The structural characteristics of the squid chitin were discussed on the basis of the IR and x‐ray analysis data. The crystalline structure of squid chitin was destroyed easily on deacetylation compared to that of shrimp chitin, and moreover, the resulting squid chitosan was amorphous unlike crystalline shrimp chitosan. The squid chitin was characterized by the remarkable affinity for organic solvents and water. Squid chitin and chitosan also showed much higher hygroscopicity and retention of the absorbed water than shrimp chitin and chitosan and are considered to be useful as highly hydrophilic materials. © 1993 John Wiley & Sons, Inc.
Swelling of interpenetrating polymer networks
Authors: Rogovina L. , Zhou Peiguang , Frisch H. L.
Published: April 2003

We have studied the densities, kinetics, and equilibrium degree of swelling in a number of different solvents of poly(carbonate urethane)/poly(methyl methacrylate) and poly(carbonate urethane)/poly(vinyl pyridine) interpenetrating polymer networks (IPN's). The kinetics of solvent uptake are often anomalous. The equilibrium extent of swelling reflects, among other factors, the number of phases present. © 1993 John Wiley & Sons, Inc.
A study of polyesters synthesized from an arylsilane and its carbon analog
Authors: Thames S. F. , Malone K. G.
Published: April 2003

Bis(4,4′‐benzoyl chloride) dimethylsilane (SiCO) and 2,2‐bis(4,4′‐benzoyl chloride) propane (CCO) were synthesized and polymerized with butanediol, resorcinol, or hydroquinone. The polymers of SiCO–hydroquinone (SiCO–Hyd) and SiCO–resorcinol (SiCO–Res) possess glass transition temperatures 25°C lower than their carbon analogs but the less aromatic SiCO–butanediol (SiCO–BDO) and CCO–butanediol (CCO–BDO) polymers have similar glass transitions. Silicon containing polymers are superior to their carbon counterparts in thermal stability. Furthermore, polyarylates of excellent thermal stability and solubility were synthesized from SiCO/terephthaloyl chloride and hydroquinone. © 1993 John Wiley & Sons, Inc.
Graft polymerization of methyl methacrylate initiated by pendant azo groups introduced onto γ‐poly(glutamic acid)
Authors: Tsubokawa Norio , Inagaki Masatoshi , Endo Takeshi
Published: April 2003

The grafting of poly(methyl methacrylate) (PMMA) onto biosynthesized γ‐poly(glutamic acid) (γ‐PGA) initiated by pendant azo groups introduced onto γ‐PGA was performed. The introduction of pendant azo groups onto γ‐PGA was achieved by the reaction of carboxyl groups of γ‐PGA with azo initiators having hydroxyl or amino groups, such as 2,2‐azobis[2‐(hydroxymethyl)propionitrile] (AHP), 2,2′‐azobis[2‐methyl‐N‐(2‐hydroxyethyl)propionamide] (AMHP), and 2,2′‐azobis[2‐(2‐imidazolin‐2‐yl)propane] (AIP), using N,N′‐dicyclohexylcarbodiimide. The amount of pendant AHP groups introduced onto γ‐PGA was estimated to be 0.15 mmol/g. Untreated γ‐PGA failed to initiate the polymerization of MMA. On the contrary, the polymerization of MMA was found to be initiated in the presence of γ‐PGA having azo groups: the polymerization rate was proportional to the square root of the concentration of γ‐PGA having pendant azo groups. During the polymerization PMMA was grafted onto γ‐PGA; the percentage of grafting of PMMA onto γ‐PGA obtained from the graft polymerization initiated by pendant AHP, AMHP, and AIP groups was evaluated to be 65.0, 53.1, and 29.0%, respectively. Differential scanning calorimetric analysis shows that the endotherm transition point of γ‐PGA at 220°C disappears by the grafting of PMMA onto the polymer. © 1993 John Wiley & Sons, Inc.
In‐situ direct polycondensation in polymer matrices. II. In‐situ direct polycondensation in styrene–butadiene block copolymers
Authors: Sanui Kohei , Ogata Naoya , Kamitani Kazuyuki , Watanabe Masayoshi
Published: April 2003

Direct polycondensation of 3‐substituted‐4‐hydroxybenzoic acid was carried out in solutions of styrene‐butadiene block copolymers (SBS) at room temperature in the presence of triphenylphosphine and hexachloroethane as an initiator for the direct polycondensation of these monomers. Solution casting after the direct polycondensation provided opaque films in which the aromatic polyester was finely dispersed within the matrix of SBS. Mechanical properties of these films were examined by tensile tests. A great improvement of tensile strength was achieved by the incorporation of phenyl substituent in the resulting polyester. In‐situ direct polycondensation leads to the formation of new composites of rigid polymers and flexible polymers. © 1993 John Wiley & Sons, Inc.