bluuebunny/crossref_metadata_2025_split huggingface dataset:
A novel way to study the initial stages of soap‐free emulsion polymerizations: The intercalation of polystyrene oligomers into hydrotalcite
Authors: Shouldice Grant T. D. , Choi Phillip Y. , Koene Bryan E. , Nazar Linda F. , Rudin Alfred 
Published: April 2003

AbstractThe dominant species in the early stages of an emulsifier‐free emulsion polymerization of styrene has been found to be an oligomer of two to three monomer units using a novel trapping technique. This involved the intercalation of charged primary oligomers between the layers of a hydrotalcite, [Mg4Al2(OH)12]2+[A]2‐ (where A = dianion). Hydrotalcites are an important class of lamellar, inorganic compounds whose interlayer spacing can be mod‐ified by anion exchange. Our approach first involved preparing a hydrotalcite precursor in which the layers were propped apart by an organic dianion (terephthalate = TA). This material was then used to capture the negatively charged polystyrene oligomers from the emulsion polymerization reaction mixture. We found that TA was rapidly ion‐exchanged for the charged oligomers.The resulting pillared hydrotalcite material was characterized using XRD and SEC. We found that the interlayer spacing between the hydroxide layers increased to 23.2 Å on exposure to the emulsion reaction mixture. This represents an interlayer expansion of 18.3 Å (after subtraction of the hydroxide layer contribution), which is cnsistent with intercalation of oligomers with two to three monomer units arranged in a bilayer. This size estimate was confirmed by the results of size exclusion chromatography. © 1995 John Wiley & Sons, Inc.
Phosphoric acid diesters protonated polyaniline: Preparation, spectroscopic properties, and processability
Authors: Laska Jadwiga , Proń Adam , Lefrant Serge 
Published: April 2003

AbstractAliphatic and aromatic diesters of phosphoric acid were tested as dopants improving pro‐cessability of polyaniline (PANI) in its doped (conducting) state. It has been found that both aromatic and aliphatic diesters effectively protonate polyaniline, inducing at the same time its solubility. The protonated state has been confirmed by three independent spec‐troscopic methods (FTIR, Raman, and UV‐vis‐NIR). Both aromatic and aliphatic diesters of phosphoric acid plasticize polyaniline which, in turn, allows for the preparation of highly conducting films of PANI or highly conducting blends of PANI with classical nonconducting polymers by thermal processing. © 1995 John Wiley & Sons, Inc.
Crosslinking study of polyethers containing pendent double bonds
Authors: Reina J. A. , Serra A. , Mantecón A. , Cádiz V. 
Published: April 2003

AbstractThis article studies the crosslinking reactions of some polyethers containing double bonds on the side chains. Thermal crosslinking takes place in all cases, but is overlapped by the degradation process. So, a catalyst has to be used to obtain the cured material and avoid degradation. The best initiator appears to be dicumyl peroxide and the maximum cross‐linking degree is achieved only with 5% (w/w). Thermogravimetric analyses are used to test the quality of the cured materials. IR spectroscopy shows that crosslinking actually takes place by polymerizing pendent double bonds. Furthermore, activation energies for thermal and radical initiated crosslinking are determined by means of dynamic DSC studies. © 1995 John Wiley & Sons, Inc.
Microemulsion polymerization of butyl acrylate. IV. Effect of emulsifier concentration
Authors: Capek Ignác , Potisk Pavol 
Published: April 2003

AbstractThe oil/water microemulsion polymerizations of butyl acrylate initiated by a water (ammonium peroxodisulfate, APS) or oil (dibenzoyl peroxide, DBP) soluble radical initiator at different emulsifier concentrations were investigated. The rate of polymerization vs. conversion curve shows two intervals. The rate of polymerization is found to decrease with the emulsifier concentration. This finding was discussed in terms of the decrease of both radical and monomer concentration, the chain transfer to emulsifier, desorption of chaintransferred radicals, and the contribution of solution polymerization. The polymerization is faster with APS. In the APS system the rate per particle or the number of radicals per particle increases exponentially with increasing particle size. The particle size and number increase during the whole polymerization. This behavior was discussed in terms of the nucleation of monomer‐containing micelles and agglomeration of primary particles during the whole polymerization. © 1995 John Wiley & Sons, Inc.
Polyether azomethines. I. Synthesis and characterization
Authors: Banerjee Susanta , Gutch Pranav K. , Saxena Chhaya 
Published: April 2003

AbstractSix new polyether azomethines were synthesized by melt and solution polycondensation of six different diamines with 4,4′‐[1,4‐phenylene bis(oxy)] bisbenzaldehyde. The polymers synthesized by solution method are yellow to white in color and had inherent viscosities up to 0.59 dL/g in concentrated H2SO4. The polymers obtained by melt condensation show higher viscosity. Except polymer IV, others are insoluble in common organic solvents. The polymers were characterized by IR, x‐ray, elemental analysis, and DSC study. The thermal stability of the polymers was evaluated by TGA and IGA study. Polymers I‐III are highly thermally and thermooxidatively stable and exhibit no appreciable decomposition up to 420°C both in air and nitrogen atmosphere. It was shown that the curing of the polyazo‐methines takes place by opening up of the CHN linkages at higher temperature. The electrical conductivities of the virgin and iodine doped polymers were as high as 10−11−10−16 and 10−6−10−8S cm−1, respectively, at 30°C. Electronic spectra of the undoped polymers (I‐III) indicated a large bathochromic shift of the ⌅ – ⌅* absorptions band (376 nm) due to CN bonds of the model compound. This can be attributed to extensive delocalization of the electrons along the polymer chain. © 1995 John Wiley & Sons, Inc.
Amphiphilic graft copolymers with poly(oxyethylene) side chains: Synthesis via phthalimidoacrylate prepolymers
Authors: Berlinova Iliyana V. , Amzil Aissa , Vladimirov Nikolai G. 
Published: April 2003

AbstractAmphiphilic graft copolymers of definite composition were obtained by grafting of amino‐functionalized poly(oxyethylene) monoether (MPEO–NH2) of M̌n = 750, 2000, and 5000 onto phthalimidoacrylate (PIA) homopolymer or its copolymer with styrene (St). The radical co‐polymerization of PIA and phthalimidomethacrylate (PIMA) with St was studied in dimeth‐ylformamide (DMF) at 60°C. The copolymer composition curves and the monomer reactivity ratios showed a high tendency of PIA to alternating copolymerization with St (r1r2 = 0.006). Hydrogen bonding between the functional groups leads to significant spectral modifications. The micellization of the graft copolymers was studied by GPC in aqueous‐methanolic eluent. The aggregation behavior of the graft copolymers depended on their composition and chromato‐graphic separation lead to the copolymers fractionation. © 1995 John Wiley & Sons, Inc.
Synthesis and characterization of α,ω‐bis(4‐hydroxybutyl) polydimethylsiloxanes
Authors: Lai Yu‐Chin , Ozark Richard , Quinn Edmond T. 
Published: April 2003

Abstractα,ω‐Bis(4‐hydroxybutyl) polydimethylsiloxane (molecular weight 1500 to 4500) can be pre‐pared with well‐controlled molecular weight through the reaction of 1,3‐bis(4‐hydroxybu‐tyl)tetramethyl disiloxane and dimethoxydimethyl silane or diethoxydimethyl silane in the presence of a stoichiometric amount of water and hydrochloric acid. The molecular weight of these hydroxybutyl‐terminated polysiloxanes can be determined fairly consistently by a titration method. These polysiloxanes are stable toward cyclization. © 1995 John Wiley & Sons, Inc.
Syntheses and characterization of UV‐curable polysiloxane‐based polyurethane prepolymers
Authors: Lai Yu‐Chin , Quinn Edmond T. 
Published: April 2003

AbstractUV‐curable polyurethane prepolymers were prepared from the following components: iso‐phorone diisocyanate, hydroxybutyl‐terminated polysiloxane, and 2‐hydroxyethyl meth‐acrylate with diethylene glycol or neopentyl glycol added as an optional chain extender. These prepolymers, with hard segments of different structures, were characterized by high resolution NMR, FTIR, and gel permeation chromatography. Model oligomers were prepared to confirm the structures of the prepolymers. The structure–property relationship of cured prepolymers were determined. © 1995 John Wiley & Sons, Inc.
Wavelength effect on the photoinduced reaction of polymethylmethacrylate
Authors: Torikai Ayako , Hattori Teruyuki , Eguchi Takuji 
Published: April 2003

AbstractPolymethylmethacrylate (PMMA) containing benzophenone (BP) was photo‐irradiated with monochromatic radiation of wavelength 260–360 nm using the Okazaki Large Spec‐trograph (OLS). On irradiation of PMMA films containing BP in air, the sensitized main‐chain scission and photocrosslinking of PMMA took place simultaneously. These reactions are dependent on irradiation wavelength. The threshold wavelength for both reactions is found to be ca. 380 nm. The number of main‐chain scission and amount of gel increased with the increase of BP concentration in PMMA. Photosensitized main‐chain scission favors the irradiation of radiation at ca. 280 nm and photocrosslinking takes place efficiently with the exposure of 340 nm radiation. A possible mechanism for photosensitized reaction is proposed. © 1995 John Wiley & Sons, Inc.
Studies of synthesis and cationic photopolymerization of three isomeric monoterpene diepoxides
Authors: Crivello James V. , Yang Bo 
Published: April 2003

AbstractThe monoterpene diepoxides isoascaridole (III), γ‐terpinene diepoxide (V), and limonene diepoxide (VIII) were prepared from the corresponding hydrocarbons and their reactivity in photoinitiated cationic polymerization examined. Both V and VIII underwent facile and rapid polymerization to give crosslinked polyethers III, but although highly reactive, did not undergo crosslinking polymerization. With the aid of model compounds it was determined that the rearrangement of one of the epoxy groups of III takes place in the presence of photogenerated acid to give an epoxy ketone (XIII) as the primary product. XIII undergoes very sluggish polymerization. © 1995 John Wiley & Sons, Inc.
Hybrid inorganic/organic interpenetrating polymer networks based on zeolite 13x and polystyrene
Authors: Frisch H. L. , Xue Yongpeng 
Published: April 2003

AbstractA hybrid inorganic/organic interpenetrating polymer network (IPN) of a three‐dimensional network structure zeolite crystal (13X, powder) and crosslinked or linear polystyrene (PS) was prepared and characterized by differential scanning calorimetry (DSC), solid‐state13C‐NMR, and scanning electron microscopy (SEM). The size and shape of the crystalline zeolite particles were revealed on SEM micrographs in both the pure zeolite and the IPNs. Solubility tests and the results of DSC with solid‐state 13C‐NMR confirm that some organic PS chains are incorporated within the internal three‐dimensional channels of the zeolite particles. We speculate that the internal PS chains may adopt an extended “one‐dimensional” conformation and exhibit no bulk polymer glass transition. These novel hybrid inorganic/organic IPNs are a new kind of IPN structure. © 1995 John Wiley & Sons, Inc.
Graft polymerization of arcylamide onto LLDPE film by electron beam pre‐irradiation in air or argon. I. Influence of dose, grafting temperature, and monomer concentration
Authors: Wirsén A. , Albertsson A.‐C. 
Published: April 2003

AbstractLinear low density polyethylene (LLDPE) film was irradiated by electron beam in air or argon prior to grafting in aqueous solutions of acrylamide containing 0.05% of Mohr's salt. The grafting kinetics was studied with pre‐irradiation doses in the range of 2.5–25 Mrad and in the temperature range of 40–70°C. Grafting rates and final degrees of grafting were higher for LLDPE pre‐irradiated in air than for LLDPE pre‐irradiated in argon. The overall activation energies for the grafting reaction were dose‐dependent. Above 5 Mrad, the overall activation energies were higher for LLDPE pre‐irradiated in argon which is interpreted as being due to crosslinking of the LLDPE. © 1995 John Wiley & Sons, Inc.
Heptane‐soluble homogeneous zirconocene catalyst: Synthesis of a single diastereomer, polymerization catalysis, and effect of silica supports
Authors: Chen You‐Xian , Rausch Marvin D. , Chien James C. W. 
Published: April 2003

AbstractBis(1‐indenyl)‐di[1′S, 2′R, 5′S)‐methoxy]silane (1) was converted into a mixture of corresponding ansa‐diastereomeric zirconocenes. Further purification afforded a single dia‐stereomer, di[(1′S, 2′R, 5′S)‐methoxy] silylene‐bis[η5‐1(R, R)‐(+)‐indenyl] dichlorozirconium (2), which is optically active and hydrocarbon soluble. Extremely rapid ethylene, propylene, and ethylene‐hexene polymerizations were observed both in toluene and n‐heptane solutions; for instance, at 50°C, activity for ethylene polymerization reaches ∼ 1.5×1010 (g of PE/((mol of Zr) · [C2H4] · h). The “bare” zirconocenium ion generated from 2/TIBA/Ph3CB(C6F5)4 exhibits unusual polymerization behaviors; the polymerization activity increases monotonically with temperature of polymerization (Tp) up to a conventional polymerization condition (50–70°C), and the 13C NMR study shows that the isotactic poly‐propylene obtained has fairly high [mmmm] methyl pentad distributions at high Tp (⩽25°C with [mmmm] ∼ 0.93–0.75) and a perfect stereoregularity at low Tp (⩽0°C with [mmmm] > 0.99). The catalyst precursors 2 and Et(Ind)2ZrCl2 (3) supported on silica by different approaches produced poly(olefins) of different molecular weights and stereoregularities, and a methylaluminokane and Ph3CB(C6F5)4 free silica‐supported zirconocene system was found to be activated by triisobutylaluminum. © 1995 John Wiley & Sons, Inc.
Polymers with amino acids in their side chain: Conformation of poly(N‐methacryloyl‐L‐methionine)
Authors: Methenitis Costas , Pneumatikakis Georges , Pitsikalis Marinos , Morcellet Joëlle , Morcellet Michel 
Published: April 2003

AbstractA homopolymer bearing L‐Methionine (PMet) in its side chain was synthesized by free radical polymerization of the corresponding vinyl monomer. Viscosimetric and pHmetric measurements indicate that PMet, in water at low pH, takes a compact conformation, which is destroyed (expanded) with increasing ionization of the carboxyl groups of the side chains. The influence of temperature and of some additives (neutral salt, urea, organic solvent, SDS) on the compact conformation and the pH‐induced conformational transition was investigated. It was concluded that hydrogen bonds are the main factors responsible for the existence of the compact conformation. © 1995 John Wiley & Sons, Inc.
Synthesis and characterization of aromatic polythiazole‐amides from new aromatic diamines containing phenyl‐pendant thiazole units
Authors: Inoue Kazuto , Imai Yoshio 
Published: April 2003

AbstractNew aromatic diamines containing phenyl‐pendant thiazole units were synthesized in three steps starting from p‐nitrobenzyl phenyl ketone. Novel aromatic polyamides containing phenyl‐pendant thiazole units were prepared by the low‐temperature solution polyconden‐sation of 1,4‐ (or 1.3‐) bis[5‐(p‐aminophenyl)‐4‐phenyl‐2‐thiazolyl] benzene with various aromatic dicarboxylic acid chlorides in N,N‐dimethylacetamide. High molecular weight polyamides having inherent viscosities of 0.5–3.0 dL/g were obtained quantitatively. The polythiazole‐amides with m‐phenylene, 4,4′‐oxydiphenylene, and 4,4′‐sulfonyldiphenylene units were soluble in N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, and pyridine, and gave transparent flexible films by casting from the solutions. These organic solvent‐soluble polyamides displayed prominent glass transition temperatures (Tg) between 257 and 325°C. On the other hand, the polythiazole‐amides with p‐phenylene and 4,4′‐biphenylene units were insoluble in most organic solvents, and had no observed Tg. All the polythiazole‐amides started to decompose at about 400°C with 10% weight loss being recorded at 450–525°C in air. © 1995 John Wiley & Sons, Inc.
Electrochemical and structural studies on soluble and conducting polymer from o‐phenylenediamine
Authors: Yano Jun 
Published: April 2003

AbstractA conducting polymer, poly(o‐phenylenediamine) (PoPD), has been obtained as stable film onto an electrode surface by the electropolymerization of o‐phenylenediamine in 0.1 mol dm−3 H2SO4. The film thickness did not exceed 0.85 μm because of its low electrical con‐ductivity. The virgin “doped” polymer film was soluble in dimethylsulfoxide N, N‐dimeth‐ylformamide, acetone, and tetrahydrofuran without any pretreatment. The highest solubility obtained was 17 g dm−3 in dimethylsufoxide. A cast film of PoPD on a substrate was prepared from its dimethylsulfoxide solution. The mean molecular weight of PoPD was found to be 11,000 with the gel permeation chromatography. The STM observation exhibited that the cast film was considerably uniform compared to the electrodeposited film. The cyclic voltammogram of such film showed a reversible redox property accompanied with excellent electrochromism between transparent yellow and brown. It was suggested from the 1H‐FTNMR and FTIR spectra and the elemental analysis that the polymeric backbone has 1, 4‐substituted benezenoid‐quinoid structure. © 1995 John Wiley & Sons, Inc.
The synthesis and study of the photoinitiated cationic polymerization of novel cycloaliphatic epoxides
Authors: Crivello James V. , Varlemann Ulrike 
Published: April 2003

AbstractThe synthesis of a series of difunctional epoxides bearing two epoxycyclohexyl groups linked together by an alkylene ether group has been carried out. Subsequently, the reactivities of these novel monomers was investigated and compared to the reactivity of the cycloali‐phatic epoxide, 3,4‐epoxycyclohexylmethyl 3′,4′‐epoxycyclohexane carboxylate (I) in pho‐toinitiated cationic polymerization. It was observed that alkylene oxide linking the two epoxycyclohexyl groups was short and the monomers are more reactive than I. The effects of the photoinitiator structure and the experimental conditions of the cationic photopo‐lymerization on the rates was also studied using real‐time infrared spectroscopy. © 1995 John Wiley & Sons, Inc.
Fundamental studies of grafting reactions in free radical copolymerization. II. Grafting of styrene, acrylate, and methacrylate monomers onto cis‐polybutadiene using AIBN initiator in solution polymerization
Authors: Huang Nai‐Jen , Sundberg Donald C. 
Published: April 2003

AbstractGrafting can be initiated by primary and/ or polymer radical attack on the backbone polymer and it is well known that AIBN does not readily promote grafting, even when using poly‐butadiene. We have studied the grafting of several different monomers onto cis‐polybuta‐diene using AIBN initiator and find dramatically different results among the monomers. As expected, styrene grafts at very low levels due to the inactivity of the initiator radicals and the polystyryl radicals. Methacrylate monomer grafts at a slightly higher level due to its more reactive polymer radical, while acrylate monomer readily grafts onto the poly‐butadiene because polyacrylate radicals are quite reactive. The use of a kinetic model allowed the evaluation of rate coefficients for graft site initiation to be in the relative order of 0.1 : 1.0 : 10.0 (L/mol/s) for styrene:methacrylate:acrylate monomers. The model also pro‐vided successful interpretations of the grafting data and its dependence upon the concen‐trations of monomer, initiator, and backbone polymer. Due to the relatively higher reactivity of the polyacrylate radicals, the benzene solvent acted as a chain transfer agent in this system. This affected the molecular weight of both free and grafted acrylate polymer and also surpressed the graft level. Polyacrylate radicals attack the cis‐polybutadiene backbone by abstracting an allylic hydrogen and also adding across the residual double bond. The latter mechanism is responsible for the majority of the grafting; the hydrogen abstraction leads to relatively inactive radicals which cause a retardation in the overall reaction rate. © 1995 John Wiley & Sons, Inc.
Fundamental studies of grafting reactions in free radical copolymerization. IV. Grafting of styrene, acrylate, and methacrylate monomers onto vinyl‐polybutadiene using benzoyl peroxide and AIBN initiators in solution polymerization.
Authors: Huang Nai‐Jen , Sundberg Donald C. 
Published: April 2003

AbstractVinyl‐1,2 polybutadiene (vinyl‐PBD) was used as the backbone polymer for the grafting of styrene, methacrylate, and acrylate monomers using both benzoyl peroxide and AIBN initiators. Radical attack on the backbone can occur through the pendant vinyl group or at the tertiary, allylic hydrogen site. Effective graft sites are formed via double bond addition of either primary (initiator) or polymer radicals. The production of tertiary allylic radicals on the backbone chain also occurs and results in moderate to dramatic reaction rate re‐tardation in every monomer system. The type of initiator is only important when the polymer radicals are not very reactive, as in the case of styrene, and to a lesser extent for methacrylate monomer. Graft efficiencies are generally higher when using vinyl‐PBD than when using cis‐PBD. © 1995 John Wiley & Sons, Inc.
Synthesis of a novel naphthalene‐based poly(arylene ether‐ketone) by polycondensation of 1,5‐bis(4‐fluorobenzoyl)‐2,6‐dimethylnaphthalene with bisphenol a
Authors: Ohno Mami , Takata Toshikazu , Endo Takeshi 
Published: April 2003

AbstractSynthesis of 1,5‐bis(4‐fluorobenzoyl)‐2,6‐dimethylnaphthalene (1), polycondensation of 1 with Bisphenol A, and properties of the obtained polymer were studied. Friedel–Crafts acylation of 2,6‐dimethylnaphthalene with 4‐fluorobenzoyl chloride in nitrobenzene selectivity afforded 1 in 82% yield. X‐ray single crystal structural analysis of 1 confirmed that the dibenzoylation proceeded regioselectively and two methyl groups sterically inhibited the coplanarity of the two aromatic planes. The polycondensation of 1 with Bisphenol A in toluene/N‐methyl‐2‐pyrrolidone (NMP) mixed solvent in the presence of excess potassium carbonate as a condensation reagent was carried out at 180°C for 4 h to quantitatively afford the corresponding poly(arylene ether‐ketone) (PEK) 3 with high molecular weight (M̄n∼30,000) as a slightly yellow powder. As the reaction time was prolonged, both M̄n and MWD of 3 increased and the solubility of 3 in chloroform clearly decreased. By GPC‐LALLS, M̄n of 3 obtained by the polycondensation for 16 h, was 85,000. The PEK 3 with high molecular weight was produced in a quantitative yield in a variety of solvents such as sulfolane. Water formed during the polycondensation hardly affected the yield and molecular weight of 3, although a small molecular weight decrease took place. To evaluate the special effect of the methyl groups of 3, polycondensation of 2,6‐bis(4‐fluorobenzoyl)naphthalene 2 with bisphenol A was carried out for comparison and the corresponding PEK 4 was quantitatively obtained. Whereas 3 was soluble in ordinary organic solvents such as tet‐rahydrofuran (THF), chloroform, and NMP at room temperature, 4 was insoluble in most solvents except for strong acids such as conc. sulfonic acid. The polymer 3 showed high glass transition temperature (238°C) and 5% weight loss temperature (457°C). Casting of the polymer from THF solution gave a transparent, tough, flexible, and amorphous film. © 1995 John Wiley & Sons, Inc.