bluuebunny/crossref_metadata_2025 huggingface dataset:
Radical‐catalyzed homopolymerization of maleic anhydride in presence of polar organic compounds
Authors: Gaylord Norman G. , Mehta Rajendra
Published: April 2003

Polar organic compounds either (1) inhibit the peroxide‐catalyzed bulk homopolymerizations of both MAH and MMA at 80°C, (2) do not inhibit the polymerization of either MAH or MMA, or (3) inhibit the polymerization of MAH but not that of MMA. Compounds generally used as polymerization inhibitors or antioxidants inhibit the polymerizations of both MAH and MMA, presumably by interaction with peroxide decomposition products. Ketones, ethers, acids, esters, nitriles, imides, sulfones, sulfonates, sulfonamides, and acyl disulfides do not inhibit either MAH or MMA polymerization. However, amides, lactams, carbamates, amine oxides, phosphites, phosphates, phosphonates, phosphoramides, phosphine oxides, monosulfides, sulfoxides, aryl disulfides, and thiazyl disulfides inhibit the polymerization of MAH but not that of MMA. Inhibition presumably occurs as a result of electron transfer from the nitrogen‐, phosphorous‐ or sulfur‐containing electron donor compound to the MAH carbocation which is an intermediate in the polymerization of MAH.
Mechanistic and kinetic studies on the photoinitiated polymerization of tetrahydrofuran
Authors: Yaǧci Yusuf , Ledwith Anthony
Published: April 2003

Polymerization of tetrahydrofuran (THF) (bulk) promoted by a free radical source, 2,2‐dimethoxy‐2‐phenyl acetophenone (DMPA), in the presence of 4,4′‐di‐(methylphenyl)iodonium hexafluorophosphate was studied in detail. Rate dependence of the polymerizing system on both DMPA and the iodonium salt was studied dilatometrically. Rate saturation for the iodonium salt was attributed to the formation of iodobenzene, which may react with propagating cations to form an iodonium salt. DMPA was shown to be an efficient transfer agent in the cationic polymerization of THF. A transfer constant for DMPA was estimated to be 2.8 and, whilst the precise details of the overall mechanism cannot be deduced from the present results, it may result in functionalized polytetrahydrofuran chains having photochemically active end groups.
Emulsifier‐free emulsion copolymerization of styrene and butyl acrylate. II. Kinetic studies in the presence of ionogenic comonomers
Authors: Guillaume J. L. , Pichot C. , Guillot J.
Published: April 2003

Batch emulsifier‐free copolymerizations of styrene (S) and butyl acrylate (BuA) have been performed for a S/BuA weight ratio = 50/50 in the presence of two types of functional comonomers [methacrylic acid (MAA) at different pHs] or potassium sulfopropylmethacrylate (SPM) and two initiators [potassium persulfate or 4–4′azobiscyanopentanoic acid (AZO)]. The use of AZO/MAA system results in the formation of polymer particles with only surface carboxylic end groups. The particle size of the final latexes can be adjusted with the MAA concentration, provided the polymerization is carried out at pH > 6.5. However, the higher the MAA concentration, the sooner the polymerization levels off in conversion. With the K2S2O8/SPM system, particles bearing only sulfate and sulfonate groups are produced and the polymerization is complete. In that case, the particle size of the final latexes is smaller than with the previous system and 30% of the SPM is fixed on the particle surface, instead of 10% with MAA. Using SPM, a too high functional monomer concentration results in the latex destabilization caused by the formation of a large amount of polyelectrolytes. Kinetic studies indicate that most of the functional monomer is incorporated onto the particle surface during the last 30% conversion of the polymerization. A tentative explanation of such a behavior is discussed, based on the existence of two polymerization loci in the latex system.
Poly(vinyl alcohol) obtained through polymerization of some vinyl esters
Authors: Imai Kiyokazu , Shiomi Tomoo , Tezuka Yasuyuki , Kawanishi Toshiaki , Jin Tomofumi
Published: April 2003

Bulk and/or solution polymerizations of a series of vinyl esters, e.g., vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate, and vinyl benzoate were conducted. Iodine‐coloration, 1,2‐glycol structure, molecular weight, and tacticity (triad and pentad) were measured for the resulting poly(vinyl alcohol)s (PVAs). The iodine‐coloration abilities of PVAs, derived from poly(vinyl ester)s that were obtained through bulk polymerization at 60°C, depended on the starting monomer, increasing in the following order: vinyl benzoate < vinyl acetate < vinyl propionate < vinyl butyrate < vinyl pivalate. In solution polymerizations of vinyl propionate and vinyl butyrate, it was revealed that the tacticity of the derived PVAs apparently depended on the type and amount of polymerization solvent employed, as found previously in the case for vinyl acetate. The iodine‐coloration of these PVA samples varied in the same order as their syndiotactic content, while no relationship was observed toward their 1,2‐glycol content. The probabilities of the syndiotactic propagation at 60°C were estimated as 0.49 (benzoate), 0.54 (acetate), 0.55 (propionate), 0.56 (butyrate), and 0.60 (pivalate), respectively.
Aromatic copolyesteramides by the direct polycondensation with diphenyl chlorophosphate and carboxamides in pyridine
Authors: Higashi Fukuji , Hirakouchi Hiroshi
Published: April 2003

The reaction promoted by a Vilsmeier adduct derived from diphenyl chlorophosphate and N,N‐dialkylcarboxamides such as N,N‐dimethylformamide was successfully used for the preparation of soluble copolyesteramides directly from aromatic dicarboxylic acids, bisphenols, and a wide range of mole percent diamines. The polycondensation was affected by the carboxamides used, and an attempt was made to explain the effect by the ester sequence in polyamide units by examining a competitive reaction of benzoic acid with a phenol and an aniline and by examining the thermal properties of the copolymers produced.
Synthesis, bulk characterization, and surface characterization of p‐hydroxystyrene/styrene copolymers
Authors: Majumdar Debesh , Ratner Buddy D.
Published: April 2003

Styrene/p‐hydroxystyrene copolymers were prepared from copolymers of styrene and p‐benzyloxystyrene by cleavage of the ether bond. Nuclear magnetic resonance spectroscopy was used to characterize the polymers before and after the ether cleavage reaction. Reactivity ratios were calculated by applying the method of least squares to data generated from the Fineman–Ross equation (r1 = 0.37, r2 = 0.28). The surface chemistry of centrifugally cast films of the homopolymers and the copolymers was studied by using electron spectroscopy for chemical analysis (ESCA). The Zisman contact angle method was used to determine the critical surface tension in air for each polymeric surface. Water contents of hydrated films were determined gravimetrically. The polar character of the surface was shown to increase to a small degree with an increase in the p‐hydroxystyrene component. Polymers with high p‐hydroxystyrene contents did not exhibit pronounced hydrogel character.
Graft copolymerization of cellulose initiated by ceric salts: Effect of reaction conditions on the consumption of ceric ion
Authors: Graczyk Tomasz , Hornof Vladimir
Published: April 2003

A soluble monomer [methyl acrylate (MA)] and an insoluble monomer [butyl methacrylate (BMA)] were grafted onto cellulose by three types of ceric salts under both oxygen‐free conditions and in the presence of oxygen. For comparison, Ce(IV) consumption during cellulose oxidation was also determined under similar reaction conditions. Slightly more Ce(IV) was consumed during cellulose oxidation in the presence of oxygen. During graft copolymerization of MA under oxygen‐free conditions, the consumption of Ce(IV) was much lower than during cellulose oxidation regardless of the type of ceric salt employed. The opposite was observed in the presence of oxygen: much more Ce(IV) was consumed during grafting than during cellulose oxidation. The consumption of Ce(IV) in the graft copolymerization of BMA by ceric sulfate was nearly independent of reaction conditions and it was approximately the same as in cellulose oxidation. In the reaction initiated by ceric ammonium nitrate under oxygen‐free conditions, less Ce(IV) was once again used up during grafting than during cellulose oxidation. However, the difference was much smaller than in the case of MA.
Characterization of the functionalization reaction product of poly(styryl)lithium with ethylene oxide
Authors: Quirk Roderic P. , Ma Jing‐Jing
Published: April 2003

The functionalization reaction of poly(styryl)lithiums (Mn = 1.3–9.9 × 103) with ethylene oxide in benzene proceeds quantitatively ( > 99%) to produce the corresponding hydroxyethylated polymer as determined by vapor phase osmometry, size exclusion chromatography, end‐group titration, thin layer chromatography, and 1H‐ and 13C‐NMR spectroscopy. 13C‐NMR spectral analysis of the functionalized polystyrene with Mn = 1.3 × 103 was consistent with addition of only one ethylene oxide unit to poly(styryl)lithium, i.e., no evidence for ethylene oxide oligomerization was observed.
Polyamide synthesis by the direct polycondensation with phenylphosphonic dichloride in pyridine
Authors: Kigashi Fukuji , Lee Yen‐Nehg , Kobayashi Akira
Published: April 2003

The direct polycondensation of isophthalic acid (IPA) and aromatic diamines with a new phosphorus compound, phenylphosphonic dichloride (PPDC), was studied. PPDC could actually react with nearly a two molar amount of carboxyl groups, but more than 75 mol % PPDC with respect to the carboxyl groups of IPA were satisfactorily used in the polycondensation. The initial reaction of IPA with PPDC in pyridine at room temperature and then at 120°C was needed to complete the activation, and the subsequent aminolysis at 120°C for 3 h was most effective. The polyamides of high inherent viscosity were obtained even from weakly basic aromatic diamines, and their values were more than those obtained by the conventional method. In their thermal properties determined by the DTA, they showed Tgs and Tms higher than those reported before.
Intumescent flame retardants for polymers. IV. The polycarbonate–aromatic sulfonates system
Authors: Ballistreri Alberto , Montaudo Giorgio , Scamporrino Emilio , Puglisi Concetto , Vitalini Daniele , Cucinella S.
Published: April 2003

The mechanism of action of aromatic sulfonates as flame retardant (FR) agents on poly(bisphenol‐A carbonate) (PC) has been investigated. These compounds are capable of inducing a self‐extinguence in PC even when present in very low amounts (0.2–1%). Thermogravimetric and flash pyrolysis–GC–MS data show the thermal degradation rate of PC enhanced, and the distribution of the volatile pyrolysis products was modified by these additives. Oxygen Index (OI) and Nitrous Oxide Index (NOI) measurements indicate a FR condensed‐phase mechanism of these additives. Traces of polymer surface temperature against time, measured under forced flame conditions, show that the expanded carbon layer formed in the combustion of polycarbonate–aromatic sulfonate blends produces a heat insulating effect toward the undecomposed bulk. The overall evidence leads us to conclude that aromatic sulfonates cause the flame extinguishment in polycarbonate by an intumescent phenomenon.
The synthesis and characterization of poly(methylene terephthalate)
Authors: Cimecioglu A. L. , East G. C. , Morshed M. , Zeronian S. H.
Published: April 2003

Poly(methylene terephthalate) (1GT) has been synthesized via the reaction of cesium or potassium terephthalates with dibromomethane or bromochloromethane in N‐methylpyrrolidone at temperatures of 80–125°C. The polymerization was relatively slower with the latter substrate, though the potassium salt was found to be equally as efficient as its cesium counterpart with dibromomethane. The polymer is insoluble in all common polyester solvents, and its high molecular weight nature (DPn ≥ 25) was inferred from elemental analyses and its fiber forming capacity. Thermal analyses indicated that 1GT possesses poor thermal stability and decomposes rapidly during melting, the initial process being thought to be the splitting out of formaldehyde. 1GT polymers were shown to contain a homologous series of cyclic oligomers (from dimer to decamer); the two most predominant were tentatively identified as the cyclic trimer and tetramer. No change in the cyclization efficiency was observed when the potassium counterion was substituted for cesium with Br CH2 Br whereas a drastic reduction in the cyclic content was obtained using Br CH2 Cl (with Cs+). The two most important features of the polymerization are the insensitivity of the reaction to the stoichiometric equivalence of the reactants and the production of reasonably high molecular weights at low conversions. It is suspected that the polymerization might be occurring through an interfacial mechanism.
Polymerization of oriented monomers. IX. Further studies on the polymerization and vesicular properties of allyl and diallyl based monomeric and polymerized quaternary ammonium salts
Authors: Babilis D. , Paleos C. M. , Dais Photis
Published: April 2003

The polymerization of the previously reported allyl and diallyl quaternary ammonium salts, which from vesicles in water, to their polymerized analogs was further investigated. The structure of the polymer derived from the diallyl derivative, for which some controversy existed, was elucidated by 13C‐NMR spectroscopy. Mixed vesicles, based on the monoallyl monomer and incorporating certain vesicle forming quaternary ammonium salts, cholesterol, or cholesteryl acrylate were also formed. These mixed vesicles were characterized primarily as far as their stability is concerned. It was found that the incorporation of the additives does not enhance the stability of the mixed vesicles compared to that exhibited by monoallyl simple vesicles. In addition, polymerization of mixed monoallyl‐cholesteryl acrylate vesicles results in the destruction of their structure. On the contrary, simple polymerized vesicles, resulting from the diallyl monomer, showed excellent long‐term stability. Specifically, samples prepared two years ago are still dispersed and, very possibly, they will remain so for a longer period since they are not showing signs of precipitation.
Investigation of the formation of poly(ethylene terephthalate) with model molecules: Kinetics and mechanisms of the catalytic esterification and alcoholysis reactions. II. Catalysis by metallic derivatives (monofunctional reactants)
Authors: Otton Jean , Ratton Serge , Vasnev Valerii A. , Markova Gali D. , Nametov Kahirman M. , Bakhmutov Vladimir I. , Komarova Lidiy I. , Vinogradova Svetlana V. , Korshak Vasilii V.
Published: April 2003

The reactions of model molecules were considered to study the kinetics and the mechanism of the esterification and the alcoholysis reactions catalyzed by various metal compounds (Li, Na, K, Zn, Co, Mn, Ti). Ti was found to be the most active catalyst for both reactions and to be acting via a different mechanism (concerted). The possible structure of the active titanium intermediate was investigated by means of 1H‐ and 13C‐NMR spectroscopy, FT–IR spectroscopy, and electroconductivity.
Preparation and properties of aromatic–aliphatic copolyamides from aromatic diisocyanates and dicarboxylic acids
Authors: Otsuki Toshihiro , Kakimoto Masa‐Aki , Imai Yoshio
Published: April 2003

Aromatic–aliphatic random copolyamides of high molecular weights were prepared by the high‐temperature solution polycondensation from a combination of aromatic diisocyanates, 4,4′‐methylenedi(phenyl isocyanate), and 2,4‐tolylene diisocyanate, and a mixture of isophthalic acid and aliphatic dicarboxylic acids with 4–10 methylene groups. Reaction conditions, such as solvent, temperature, time, and catalyst were studied to determine the optimum conditions for the preparation of high molecular weight polymers. Glass transition temperatures of the copolyamides were in the range of 131–244°C and varied with combination and composition of the diisocyanates and dicarboxylic acids used. The copolyamides prepared from 2,4‐tolylene diisocyanate had greater solubility and higher glass transition temperatures than those obtained from 4,4′‐methylenedi(phenyl isocyanate).
Synthesis, free‐radical polymerization, and stereochemical configuration of methyl α‐p‐cyanobenzylacrylate
Authors: Madruga E. L. , Román J. San , Alcalde J. , Fernandez‐Monreal M. C.
Published: April 2003

Methyl α‐p‐cyanobenzylacrylate was synthesized from dimethyl malonate following well‐known organic reactions. The purified monomer was polymerized by a free‐radical mechanism in benzene solution, using AIBN as initiator in the interval 50–90°C. The kinetic results seem to indicate an apparent ceiling temperature near 90°C. The analysis by 13C‐NMR of polymers obtained indicates that the macromolecular chains are predominantly syndiotactic and the tacticity is independent of the polymerization temperature in the experimental interval studied. However, the determination of conditional probabilities for iso‐ and syndiotactic additions and the persistence ratios indicate that the propagation mechanism for the radical polymerization of methyl α‐p‐cyanobenzylacrylate does not follow a typical Bernoullian statistics.
Emulsion polymerizations. II. Kinetics, molecular weight distributions, and polymer microstructure of emulsion copolymers
Authors: Giannetti Enzo , Storti Giuseppe , Morbidelli Massimo
Published: April 2003

The kinetics of emulsion copolymerizing systems during intervals II and III (i.e., after completion of latex particle formation) has been studied through the pseudo‐homopolymerization approach. The Smith–Ewart equations for copolymers are reduced to the corresponding equations for homopolymers by introducing suitable pseudo‐homopolymerization parameters. Analogies and differences between our results and those of previously reported treatment are critically discussed. On the grounds of the probabilistic approach developed in Part I of this series, a detailed description of the copolymer chain structure is derived for systems containing no more than one growing radical per particle. In particular explicit algebraic relationships are reported for both the two‐dimensional molecular weight distribution and the unidimensional marginal distribution functions of molecular weight and chemical composition. A complete description of the chain microstructure is also reported. Equations are derived specifying the time evolution of the monomer sequence distribution and polymer end groups.
Perfume alcohols supported to sulfochlorinated poly(styrene‐co‐divinyl benzene) beads
Authors: Galioǧlu Oya , Akar Ahmet
Published: April 2003

Perfume alcohols such as 2‐phenyl ethanol and eugenol were supported to sulfochlorinated poly(styrene‐co‐divinyl benzene) beads in the presence of base such as triethyl amine, pyridine, and sodium bicarbonate and their hydrolysis at different temperature was studied.
Metallocene–methylaluminoxane catalyst for olefin polymerization. II. Bis‐η5‐(neomenthyl cyclopentadienyl)zirconium dichloride
Authors: Chien James C. W. , Razavi Abbas
Published: April 2003

Bis(neomenthyl cyclopentadienyl)zirconium dichloride/methyl aluminoxane (η5‐(NMCp)2ZrCl2/MAO) catalyst has been investigated for ethylene polymerization. About 51% of the Zr forms active sites more or less instantaneously according to quenching with tritiated methanol. There is an initial drop of rate of polymerization, Rp, of about 30% which remains constant thereafter. The catalytic activity increases monotonically with temperature; it is proportional to [MAO]1.75 at a constant [Zr] = 1.5 μM and proportional to [Zr]−1.2 at a constant [MAO] = 64.5 mM. At very large [MAO]/[Zr], the catalyst has extremely high activity; κp = 5 × 103 (Ms)−1 at 50°C. There is also facile chain transfer to aluminum, κ = 0.14 s−1 at 50°C. Both κp and κ are about 30 times greater than the corresponding rate constants for MgCl2 supported TiCl3 catalysts. The TiCl3/MgCl2 and (NMCp)2/MAO catalysts have nearly the same activation energy for propagation (ca. 7 kcal/mol−1). The higher activity of the latter is due to its larger preexponential factor in κp. The dependence of catalytic activity on the [MAO]/[Zr] ratio may be explained by rapid association‐dissociation equilibria of MAO involving acid‐base and/or electron deficient bridge complexation.
Reactivities of methacrylate derivatives in radical polymerization as evaluated by mercury method
Authors: Ueda Mitsuru , Mano Motokazu , Ito Hiroshi
Published: April 2003

Reactivities of methyl methacrylate derivatives bearing substituents on the ester methyl group have been investigated by competitively adding a cyclohexyl radical generated by a reaction of cyclohexylmercuric chloride with sodium borohydride (mercury method) to these substituted methacrylates and methyl methacrylate or styrene. The relative rate constants of the cyclohexyl radical addition have been found to be nicely correlated with parameters such as Traft α* constants of alkyl esters, Q–e values, lowest unoccupied molecular orbital energies, β‐carbon chemical shifts, and relative reactivities toward a polystyryl radical, indicating that the mercury method is a simple and useful technique for evaluation of the relationship between structure and reactivity of vinyl monomers in their radical polymerization, even when the structural modification is small.
Thermotropic copolyesters. III. Synthesis and characterization of liquid crystal copolyesters containing the bicyclo[2.2.2]octane ring system
Authors: Polk Malcolm B. , Banks Harold D. , Onwumere Fidelis , Venkatasubramanian N. , Nandu Mahendra , Phingbodhipakkiya Metha , Samulski Edward T.
Published: April 2003

A number of thermotropic copolyesters which contain the bicylo[2.2.2]octane ring system have been synthesized. Because of the stiffening effect of the bicyclo[2.2.2]octane group on the chain, the sebacoyl spacer was used to obtain meltable compositions.
The effect of divinylsulfone on the irradiation crosslinking of polypropylene
Authors: Sasaki Yusuke , Imai Masahiko , Tanaka Jun , Shimizu Harumichi
Published: April 2003

Polypropylene films were irradiated with 60Co γ‐rays in divinylsulfone (DVS) or butadiene (BD) gases. The variations of the intrinsic viscosities of the samples irradiated in vacuum or in DVS with dose showed usual patterns but the variation of the latter was somewhat more rapid. The intrinsic viscosity of the sample irradiated in BD could not be measured due to the early appearance of gel. The gel fraction of the sample irradiated in DVS appeared at lower dose than that irradiated in vacuum, but the former did not increase as much as the latter. The gel fraction of the sample irradiated in BD increased remarkably. The concentrations of the two kinds of double bonds increased in the sample irradiated in BD but levelled off gradually with dose. ESR study showed that the polypropylene radical reacted with DVS to form anisotropic radicals. The mechanisms of the effects of both reagents on irradiation of polypropylene were discussed.
Control of composition in ethylene copolymerizations using magnesium chloride supported Ziegler–Natta catalysts
Authors: Mulhaupt Rolf , Ovenall Derick W. , Ittel Steven D.
Published: April 2003

Incorporation of a sterically hindered phenol (2,6‐di‐tert‐butyl‐4‐methylphenol) during the preparation of MgCl2‐supported titanium catalysts coupled with the use of an aluminum alkyl activator modified with the same phenol and an electron donor such as ethyl benzoate allows the systematic modification of the reactivity ratios of ethylene and 1‐olefin copolymerizations. The polymers obtained tend to be largely random with a tendency toward alternating at high comonomer incorporation. Very low density LLDPE copolymers have been prepared in stable slurry polymerizations. The same catalysts allow the preparation of copolymers with dienes.
A new approach to high temperature photoresists based on styrylpyridinium units
Authors: Li Min Yu , Pearce Eli M. , Reiser A. , Narang S.
Published: April 2003

Four linear polyesters containing styrylpyridinium units were prepared from 2,6‐bis(p‐hydroxystyryl)pyridine and terephthalic acid, isophthalic acid, adipic acid, and sebacic acid, respectively. The polyesters are thermally stable in the 365 to 450°C range. The decomposition temperature is higher for aromatic polyesters, lower for their aliphatic analogs. The polyesters are photoreactive and crosslink on irradiation with UV. The crosslinking mechanism is 2 + 2 cycloaddition. The polyesters form protonated complexes with CF3COOH which absorb at longer wavelengths and are also photoreactive. The quantum yield of the photoreaction and the relative photosensitivities of the polyesters and their complexes were determined.
Pseudoheterogeneous polymerization of methyl methacrylate in presence of some metal chlorides or sulfates
Authors: Badran A. S. , Helaly F. M. , Younan A. F.
Published: April 2003

The aqueous pseudoheterogeneous polymerization of methyl methacrylate in the absence and presence of some metal chlorides or sulfates was carried out in nitrogen atmosphere at 40°C using sodium bisulfite as initiator. The metal chlorides or sulfates were found to catalyze the rate of polymerization of methyl methacrylate to different extents. The highest effect was obtained in the presence of copper salts, a moderate effect was obtained when iron salts were used, and the least effect was caused by the others. All 13C‐NMR spectra for the polymers obtained in the absence and presence of some metal salts were those to be expected for radically initiated poly(methyl methacrylate)s of conventional, slightly syndiotactic‐rich microstructures prepared at normal temperature. The spectra were found to be very similar to that for a radical poly(methyl methacrylate) first analyzed by Inoue et al. The ratios of isotactic (mm): heterotactic (mr,rm): syndiotactic (rr) triads were found to be close to 6 : 32 : 62. The polydispersity for some poly(methyl methacrylate)s determined by gel permeation chromatography technique was found here to vary rather widely and ranges between 1.8 and 8.92.
Crosslinking of polystyrene under friedel–crafts conditions in dichloroethane and carbon tetrachloride solvents through the formation of strongly colored polymer–AlCl3–solvent complexes
Authors: Rabek Jan F. , Lucki Julia
Published: April 2003

Polystyrene was crosslinked in either 1,2‐dichloroethane or carbon tetrachloride in the presence of aluminum chloride. Apparently, the reactions involve Friedel–Crafts substitution of phenyl ring with CH2CH2Cl or CCl3 groups, which than participate in crosslinking, giving CH2CH2 or CCl2, CCl, and C bridges. In the first stage a charge‐transfer complex is formed between AlCl3, polystyrene and the solvent. After heating this complex above 35–40°C a rapid formation of HCl occurs and a crosslinked polymer is formed. This final product is insoluble, infusible, and inflammable. It decomposes at 400°C without melting.
Synthesis of organotin polymers by the reaction of diallyl carbonates with Bu3SNH
Authors: Moriya Osamu , Arai Seiji , Endo Takeshi
Published: April 2003

Tri‐n‐butyltin hydride (Bu3SnH) was employed for the synthesis of organotin polymers via radical process. The polymers having both organotin and carbonate groups were obtained by the reaction of Bu3SnH with monomers such as diallylcarbonate and diethylene glycol bis(allyl carbonate) via hydrostannation. The copolymerization of diethylene glycol bis(allyl carbonate) and the mono‐hydrostannated derivative was also conducted to obtain the corresponding polymers.
Poly(phenylene sulfide): Synthesis from 1,4‐dibromobenzene and sodium sulfide
Authors: Rajan C. R. , Nadkarni V. M. , Ponrathnam S.
Published: April 2003

A new route to synthesize poly(p‐phenylene sulfide) by nucleophilic substitution of 1,4‐dibromobenzene with sodium sulfide in N‐methylpyrrolidone is described. Kinetic evaluation shows the reaction to be of second order with two distinctive rate constant regimes. The first rate constant is higher and is operative until 50% conversion, whereas in the second regime (between 50 and 92% conversion) the rate is slower. The kinetics of this route is compared under identical conditions with the conventional synthesis based on 1,4‐dichloro benzene and sodium sulfide.
Polyesters from α,α′‐dicarbomethoxy‐α,α′‐diphenyl‐p‐xylylene and the synthesis and properties of a new quinodimethane
Authors: Mulvaney J. E. , Green G. David
Published: April 2003

A film forming polyester was obtained from the title compound and 1,4‐butanediol. In addition oxidation of the title compound gave rise to 7,8‐dicarbomethoxy‐7,8‐diphenylquinodimethane as a mixture of Z and E isomers. The 1H‐NMR and the electronic characterization of this polymer are discussed. The quinodimethane will undergo 1,6‐nucleophilic addition to form an aromatic compound.
The synthesis of poly(hydroxamic acid) from poly(acrylamide)
Authors: Domb A. J. , Cravalho E. G. , Langer R.
Published: April 2003

Poly(hydroxamic acid) in gel or water soluble from was prepared from the reaction of poly(acrylamide) and hydroxylamine in basic aqueous solution (pH > 12) at room temperature. The polymers were composed of 70% hydroxamic acid groups, less than 5% carboxylic acid groups, and 25% unreacted amide groups. The polymers exhibited high affinity to iron(III) and copper(II) in the pH range of 1 to 5 with a high binding rate. A binding of 3 mmol/g for both metals was achieved. Preliminary tests demonstrated the urease inhibitory activity of both linear and crosslinked poly(hydroxamic acids).
Longitudinal volume viscosity of poly(methyl methacrylate)
Authors: Hurtado‐Laguna F. , Aleman J. V.
Published: April 2003

Volume flow of poly(methyl methacrylate) (PMMA) (M̄n = 43,000 and Tg = 384) has been measured in an Instron Capillary Rheometer. Elastic modulus of the longitudinal wave, longitudinal volume viscosity, initial longitudinal volume viscosity, and retardation times are described at temperatures above Tg (418–483K) and compression rates of about 1.00–200.00 × 105 s−1. An initial increase followed by a decrease in longitudinal volume viscosity has been observed as the compression rate increases and the volume deformation decreases, this last behavior being at the lowest values of the compression rate (6.0 and 30.0 × 10−5 s−1) a typical nonequilibrium one. ηL also increases with increasing temperature (Tg decreases 0.18°C/MPa), and volume flow activation energy decreases as the volume deformation increases.
Radiolysis of polymers of chlorine methacrylates
Authors: Wuensche P. , Mueller S. , Lorkowski H.‐J.
Published: April 2003

Polymers of α‐chloroacrylate (MCA), 1‐chloroethyl methacrylate (1CEMA), 2‐chloroethyl methacrylate (2CEMA), 2,2,2‐trichloroethyl methacrylate (trCEMA) and 1,2,2,2‐tetrachloroethyl methacrylate (teCEMA) were γ‐irradiated at 77 K. The primary radicals were generated by the abstraction of chlorine. They decay or change into chain end radicals upon warming up to room temperature.
Photoreactive polyamides having m‐ or 1‐type dimer moiety derived from 4‐(3‐oxo‐3‐phenyl‐1‐propenyl)benzoic acid derivatives
Authors: Nohara Masao , Hasegawa Masaki , Harashina Hatsuhiko , Iitaka Yoichi
Published: April 2003

Photoreactive polyamides having m‐ or 1‐type cyclobutane moiety were prepared via a topochemical photodimerization of 4‐(3‐oxo‐3‐phenyl‐1‐propenyl)benzoic derivatives,4 followed by polycondensation of cyclobutane dicarboxylate derivatives with diamines. From the spectral studies of resulted polyamides compared with the corresponding reference diamides, it was concluded that both types of polyamides were depolymerized photochemically to give the same type of amide derivative having chalcone moiety with a small amount of undefined side reaction. The cyclobutane ring of the m‐dimer from 4‐(3‐oxo‐3‐phenyl‐1‐propenyl)benzoic acid in crystal is severely twisted presumably because of the enhanced steric repulsions between two pairs of adjacent substituents. The higher quantum yield of the m‐dimer for the photocleavege, compared with that of the 1‐dimer, has been interpreted in terms of such steric repulsions by the strained structure of the m‐dimer.
Reaction of triphenylphosphine with poly(ethylene terephthalate) and certain model compounds at elevated temperature
Authors: Suebsaeng Thitivat , Wilkie Charles A. , Brown Charles E.
Published: April 2003

Triphenylphosphine and poly(ethylene terephthalate) react at 370°C to produce ethylene, triphenylphosphine oxide, carbon dioxide, benzoic acid, and terephthalic acid. The reaction proceeds by the initial formation of a zwitterionic species which then generates a phosphonium ylid and leads to the observed products. Any flame retardant activity from the use of triphenyl‐phosphine may be attributed to the formation of triphenylphosphine oxide. The co‐production of ethylene renders triphenylphosphine a less effective flame retardant than triphenylphosphine oxide.
Synthesis and polymerization of 2‐butyl‐7‐methylene‐1,4,6‐trioxaspiro(4,4)nonane
Authors: Pan Cai‐Yuan , Wang Yin , Bailey William J.
Published: April 2003

2‐Butyl‐7‐methylene‐1,4,6‐trioxaspiro(4,4)nonane (7) was prepared by the reaction of 2‐(bromomethyl)‐5‐oxo‐tetrahydrofuran with 1,2‐epoxyhexane, followed by dehydrobromination. Compound 7 could be polymerized by free radical initiators to give a viscous polymer. The IR and NMR spectra of the polymers indicated that the polymer structure contained ester and ketone units in the backbone, and a cyclic acetal side chain. Compound 7 readily copolymerized with acrylonitrile in the presence and absence of radical initiators, but did not copolymerize well with styrene. Ultraviolet spectra suggest that the spontaneous polymerization proceeds via a chargetransfer complex between 7 as an electron donor and AN as an electron acceptor.
Powder and fiber filled interpenetrating network of metal polymer composites (INMPC) of polypropylene
Authors: Semsarzadeh Mohammad Ali , Hudgin Donald E.
Published: April 2003

The mechanical properties of conductive powder and fiber‐filled interpenetrating network of polymer metal composites (INMPC) of polypropylene with metal alloys based on Sn, Zn, Mo, Al, Cu, Ag, and Sb are reported. New nomenclature, terminologies, and definitions are presented. New models are also discussed.
Study of the synthesis of poly(isobutylene‐b‐amide‐11) by polycondensation of α,ω‐dianhydride oligoisobutylene with α,ω‐diamino oligoamide‐11. I. Study of amine–anhydride and amide–anhydride reactions on low molecular weight models and on oligomers and polymers
Authors: Tessier Martine , Marechal Ernest
Published: April 2003

The side reactions connected with the polycondensation of α,ω‐diamino oligoamides and α,ω‐dianhydride oligoisobutylenes are studied on low and high molecular weight models. Models for amine and anhydride end groups are dodecylamine and (2‐dodecene‐1‐yl) succinic anhydride, respectively; their reaction is studied in the bulk (170°C) and in solution (142, 152, and 162°C); the products are analyzed by 1H‐, 13C‐, and 1H‐13C‐NMR and GPC. Some of these products and the junctions between the blocks are prepared independently. Models of amide groups in the chain are N‐dodecyldodecanamide and N‐dodecyloctadecanamide; their reaction with anhydride model results in cleavages with formation of imide groups. The results obtained from low molecular weight models are confirmed by studies on oligomers. They show unambiguous by that crosslinking which accompanies the block polycondensation originates from the reaction of amino‐end groups with the intermediary acid groups resulting from the amine‐anhydride reaction.
Bismaleimides and bisnadimides derived from 2,5‐bis(4‐aminophenyl)‐3,4‐diphenylthiophene and their polymerization to heat‐resistant matrix resins
Authors: Mikroyannidis John A. , Koutsolelos Panayiotis G.
Published: April 2003

Six new structurally different bismaleimides or bisnadimides based on 2,5‐bis(4‐aminophenyl)‐3,4‐diphenylthiophene (BADT) were synthesized and characterized by infrared (IR) and proton nuclear magnetic resonance (1H‐NMR) spectroscopy. Chain‐extension of several bismaleimides was accomplished by incorporating various imide, amide, and urea groups. The bismaleimide and bisnadimide prepared by reacting BADT with maleic or nadic anhydride, respectively, were soluble in various organic solvents. The monomers were thermally polymerized or by a Michael reaction with certain aromatic diamines. Curing behavior was investigated by differential thermal analysis (DTA). The thermal and thermo‐oxidative stability of polymers was evaluated by dynamic thermogravimetric analysis (TGA) and isothermal gravimetric analysis (IGA). The polymers derived from bismaleimide of BADT as well as from the bismaleimides chain‐extended by imide groups were stable up to 355–392°C in N2 or air and afforded anaerobic char yield 66–74% at 800°C. The polymers obtained by curing the bismaleimide‐diamine adducts showed a relatively lower thermal stability.
Effect of stirring on photoinitiated polymerization
Authors: Zanocco A. , Garrido J. , Lissi E. A.
Published: April 2003

The polymerization of methyl methacrylate photosensitized by benzion methyl ether over a wide range of initiator absorbances was investigated. Both the polymerization rate and the polymer molecular weight distribution are modified by stirring the solution at c.a. 700 rpm. The results obtained can be explained in terms of an inhomogeneous distribution of the polymeric macroradicals under nonstirred conditions. This effect can be related to the attenuation of the light beam across the reactor, and hence is determined by the optical density of the reacting mixture.
The surface photopolymerization of perfluorobenzene and photocopolymerization of perfluorobenzene/benzene: A possible model for plasma polymerization
Authors: Munro H. S. , Till C.
Published: April 2003

ESCA has been used to characterize films deposited from perfluorobenzene and perfluorobenzene/benzene vapors during plasma polymerization and irradiation with vacuum ultraviolet light. The films deposited by both methods are shown to be essentially the same. This indicates that similar electronically excited states are involved in the formation of the precursors to deposition in both methods and that reaction mechanisms involving ions do not need to be considered for the plasma polymerization of the monomers investigated.
Synthesis and characterization of phenyl‐pendant aromatic polythiazoles from bis‐α‐bromophenylacetyl compounds and dithioamides
Authors: Inoue Kazuto , Ueda Mitsuru , Imai Yoshio
Published: April 2003

Novel phenyl‐pendant aromatic polythiazoles having inherent viscosities of 0.3–1.3 dL/g were synthesized by the solution polycondensation of bis[4‐(α‐bromophenylacetyl)phenyl] ether with aromatic dithioamides or dithiooxamide in dimethylformamide at 60°C. The polythiazole having m‐phenylene linkage was readily soluble in chloroform and m‐cresol, and transparent flexible film could be cast from the chloroform solution. Glass transition temperatures of these polythiazoles were in the range of 210–250°C. They started to decompose at about 500°C in air with 10% weight loss being recorded at around 570°C.
Processable, high temperature polymers from 1,4,5,8‐tetrahydro‐1,4;5,8‐diepoxyanthracene and bis‐dienes
Authors: Meador Mary Ann B.
Published: April 2003

1,4,5,8‐tetrahydro‐1,4;5,8‐diepoxyanthracene reacts with various anthracene end‐capped polyimide oligomers to form Diels–Alder cycloaddition copolymers. The polymers are soluble in common organic solvents, and have molecular weights of approximately 21000 to 32000. Interestingly, these resins exhibit lower weight loss in air than in nitrogen. This is suggested to be due to dehydration (loss of water ranges from 2 to 5%) at temperatures of 390 to 400°C to give thermooxidatively stable pentiptycene units along the polymer backbone. Because of their high softening points and good thermooxidative stability, the polymers have potential as processable, matrix resins for high temperature composite applications.
Polycondensation of bis(p‐nitrophenyl) β‐truxinate with diamine
Authors: Iizawa Takashi , Miyaji Takatoshi , Nishikubo Tadatomi
Published: April 2003

Model reaction of bis(4‐nitrophenyl) β‐truxinate (BNPT) with aliphatic amines proceeded quantitatively at room temperature. Accordingly, polycondensation of BNPT with various diamines was carried out at room temperature or 80°C. During the polycondensation of BNPT with diamines, the precipitation of polymer or the observed gelation of polymerization solution occurred, which may limit the molecular weight of the polymer. On the other hand, the reaction of BNPT with 1,3‐(4‐piperidyl)propane (DPP) proceeded homogeneously to give the polymer with relatively high molecular weight, and the obtained polyamide (P‐1e) showed excellent solubility in many solvents. The study of TG and DTA indicated that the obtained polymers were stable at lower temperature than around 270°C. The polymer prepared from the polycondensation of BNPT with hexamethylenediamine showed melting point and decomposition due to the imidation at 282°C. The photochemical reaction of these polymers was carried out in the film state. The irradiation of 254 nm light caused an absorption at 272 nm to appear and the molecular weight to decrease. This meant that the scission of cyclobutane ring in the main chain occurred to give cinnamamide structures. Also, the absorption at 272 nm decreased by the irradiation of 302.5 nm light. However, the UV spectrum of irradiated polymer did not agree with that of the original polymer. These results suggested that the dimerization of the resulting cinnamamide moieties occurred in the competition of their trans–cis‐isomerization. On the other hand, the rate of scission of cyclobutane ring of P‐1e was faster than that of the corresponding polyamide containing α‐truxillamide structure.
Synthesis of fluorine‐containing graft copolyamides by using condensation‐type macromonomers
Authors: Chujo Yoshiki , Hiraiwa Akihiko , Kobayashi Hisaaki , Yamashita Yuya
Published: April 2003

Fluorine‐containing graft copolyamides were prepared from condensation‐type macromonomers. Dicarboxyl‐terminated poly(perfluoroalkylethyl acrylate) was prepared by radical chain transfer polymerization and copolycondensed with diamines and dicarboxylic acids in the presence of triphenylphosphine and pyridine. Nylon‐6 films containing various amounts of the resulting graft copolyamides were obtained by heat pressing. Only 5 wt % of graft copolymers were sufficient to make nylon‐6 surfaces water repellent.
Synthesis and characterization of monomers and polymers of acrylated phosphonate esters derived from glycerol, D‐mannitol, D‐sorbitol, pentaerythritol, and dipentaerythritol
Authors: Cabasso Israel , Sahni Suresh K. , Vofsi David
Published: April 2003

Phosphonic acid ester derivatives of glycerol, D‐mannitol, D‐sorbitol, pentaerythritol, and dipentaerythritol have been synthesized by transacetalation reactions with diethyl 2,2‐diethoxyethylphosphonate. These phosphonated derivatives of polyols and carbohydrates have been esterified to from the corresponding methacrylates. All these compounds have been characterized on the basis of their elemental analysis and spectroscopic (infrared including FT–IR, 1H‐, 13C‐, 31P‐NMR, and mass) methods. Transacetalation reactions with dialkyl 2,2‐dialkoxyethylphosphonate lead to the synthesis of 1,3‐dioxane derivatives in the case of D‐mannitol, pentaerythritol, and dipentaerythritol, whereas a mixture of both 1,3‐dioxane and 1,3‐dioxolane derivatives is obtained with D‐sorbitol and glycerol. The methacrylates of phosphonylated polyol derivatives show the capacity to dissolve and interact with metal salts such as bismuth bromide and uranyl nitrate. Some of the polymers obtained from these monomers have been characterized on the basis of their spectral and thermal (differential scanning calorimetry) properties.
Metallocene–methylaluminoxane catalysts for olefin polymerization. I. Trimethylaluminum as coactivator
Authors: Chien James C. W. , Wang Bor‐Ping
Published: April 2003

Ethylene was polymerized by Cp2ZrCl2–methylaluminoxane (MAO) catalysts where a portion of the MAO was replaced with trimethyl aluminum (TMA). At a total Al to Zr ratio of 1070, there is neither appreciable loss of productivity nor change in polymerization profile for TMA/MAO ≤ 10. The productivity is reduced only by two‐ to three‐fold for TMA/MAO ≤ 100 accompanied by a 10 min induction period. Aging of this catalyst did not affect the induction period, but improves its productivity. The kinetic isotope effect for radiolabeling with tritiated methanol is 2.0. About 40% of the Zr is active for the catalyst with {99 [TMA] + 1[MAO]} to Zr ratio of 100. The rate constants for propagation and chain transfer were obtained. The mechanisms for the mixed TMA and MAO cocatalyst system are discussed. The results of this work have important practical significance. MAO is a hazardous material to synthesize and only in low yields. The replacement of > 90% of MAO with TMA represents a substantial saving since as much as 0.1M of the former is commonly used for a polymerization.
Gel permeation chromatography of polyamide by N‐trifluoroacetylation
Authors: Ogawa Toshio , Sakai Masakazu
Published: April 2003

Successful chromatograms were obtained for trifluoroacetylated nylon 12 (N‐TFA‐N) in gel permeation chromatography (GPC) with dichloromethane as eluent. It was confirmed that the method of universal calibration was applicable for N‐TFA‐N and polystyrene. The average molecular weights of nylon 12 were obtained from the chromatogram of N‐TFA‐N by use of the calibration curve for polystyrene. The stability of N‐TFA‐N in solution was examined from various angles. Satisfactory results are obtained, if the sample solution is measured within 48 h after preparation.
Polymerization of 1,3,5‐trithiane in the solid state initiated by UV‐irradiation. I. Polymerization conditions and polymer characterization
Authors: Andrzejewska Ewa , Żuk Aleksander , Garbarczyk Józef
Published: April 2003

The solid‐state 1,3,5‐trithiane polymerization initiated by UV‐irradiation was studied at various irradiation times and various polymerization temperatures. The conversion of monomer to polymer reaches limiting values (at longest) in about 30 min of reaction. The apparent activation energy of this process is somewhat higher than in the chemically initiated polymerization. Generated by UV, active centers, which initiate the polymerization, are stable. On the basis of X‐ray diffraction studies it was found that the prepared polythiomethylene has a hexagonal structure and high degree of crystallinity. In the polymer investigated, a new additional crystal phase is formed, which is not stable.
The synthesis and lithographic evaluation of a new organosilicon novolac‐based resist
Authors: Tarascon R. , Shugard A. , Dabbagh G.
Published: April 2003

A novel material, bis(trimethylsilylmethoxy resorcinol) was synthesized by a phenoxide alkylation method. The new substituted resorcinol was then terpolymerized with 2‐methyl resorcinol and formaldehyde. We evaluated the preparation of this new polymer in terms of feed ratio of the reactants, reaction time, and temperature; and prepared a series of materials with different silicon content. Polymers which retained base solubility at high silicon content were blended with a dissolution inhibitor, and studied for their lithographic capabilities as positive, photo‐ or electron‐beam bilevel resists. When used in a photoresist formulation a dose of 120 mJ/cm2 allowed formation of submicron features. When used in an electron‐beam resist formulation 0.5 μm line/space patterns were obtained at a dose of 10 μC/cm2. Furthermore, these materials displayed etching ratios relative to hardbaked HPR206 of ≃ 1 : 10. This value is believed to be large enough to allow these resists to withstand reactive ion etching conditions for pattern transfer in a bilevel scheme.