bluuebunny/crossref_metadata_2025 huggingface dataset:
Emulsion polymerization of vinyl acetate using a polymerizable surfactant. II. Polymerization mechanism
Authors: Urquiola M. B. , Dimonie V. L. , Sudol E. D. , El‐Aasser M. S.
Published: April 2003

The mechanism of growth of latex particles in the emulsion polymerization of vinyl acetate using a polymerizable surfactant, sodium dodecyl allyl sulfosuccinate (TREM LF‐40; Henkel) was investigated. Both the aqueous phase and the particle/water interface were found to be loci for the copolymerization of TREM LF‐40 with vinyl acetate. Competitive growth experiments using TREM LF‐40 and its nonpolymerizable derivative were conducted to separate the effects of aqueous phase and particle surface. Particle size analysis of the seeded and unseeded polymerizations coupled with kinetic results suggested that the reactions at the particle/water interface are more important and that the particle size of the latexes is a key parameter controlling the polymerization rate through copolymerization and chain transfer to the polymerizable surfactant at the particle surface. A decrease in particle size lead to an increase in the amount of TREM LF‐40 polymerized at the particle surface and to a decrease in polymerization rate. © 1992 John Wiley & Sons, Inc.
Dithiadiazolium salts as initiators for the cationic ring‐opening polymerization of tetrahydrofuran
Authors: Banister Arthur J. , Luke Anthony W.
Published: April 2003

Mono‐, bis‐ and tris‐(1,3,2,4‐dithiadiazolium) salts [R‐(CNSNS+)n]n+[AsF‐6]n (R = aryl, n = 1, 2, 3) were found to initiate the cationic ring‐opening polymerization of tetrahydrofuran (THF) at room temperature to give clear gels from which the pure polymer was precipitated. 1,3,2,4‐Dithiadiazolium cations associated with the hard [AsF6]‐ anion thus constitute a new class of cationic polymerization initiators. The poly(THF) formed by initiation with 1,3,2,4‐dithiadiazolium cation was characterized by gel permeation chromatography, infrared spectrophotometry, and 13C‐NMR spectroscopy. Number‐average molecular weights of 198 700 g mol‐1 (polydispersity 1.96) and 190 000 g mol‐1 (polydispersity 1.61) were obtained using [PhCNSNS] [AsF6] and [C6H3‐1,3,5‐(CNSNS)3][AsF6]3, respectively, as initiators. The use of multifunctional dithiadiazolium salts as initiators suggests that they may be useful in the preparation of starburst and dendritic polymers. © 1992 John Wiley & Sons, Inc.
Polymer‐supported palladium and platinum species as hydrogenation catalysts
Authors: Xavier Regina , Mahadevan V.
Published: April 2003

The synthesis of new hydrogel copolymers and their use for anchoring Pd and Pt species is described. The supported catalysts are effective for the reduction of alkenes, dienes, alkynes, and nitroaromatics under mild conditions. The catalysts have been characterized by chemical analysis, particle size measurement, IR, TGA, and x‐ray photoelectron spectra. Relative reactivities and the effects of substrate structure, solvents, catalyst loading, particle size of the catalysts, and partial pressure of hydrogen have been determined. The kinetics of hydrogenation have been analyzed using concepts useful under slurry reaction conditions. The recycling efficiencies of the catalysts and product analysis to establish selectivities have been assessed. © 1992 John Wiley & Sons, Inc.
Photooxidation of polystyrene by O2 and N2O
Authors: Wells R. K. , Badyal J. P. S.
Published: April 2003

Strips of polystyrene held in a flowing O2 or N2O atmosphere have been exposed to 240‐600 nm radiation. The extent of photooxidation has been followed by x‐ray photoelectron spectroscopy (XPS). Although N2O is a more reactive gas than O2, it produces a less oxidized polymer surface. This surprising observation can be correlated to the photochemistry occurring at the gas/polystyrene interface. © 1992 John Wiley & Sons, Inc.
Plasma copolymerization of ethylene and tetrafluoroethylene
Authors: Golub Morton A. , Wydeven Theodore , Cormia Robert D.
Published: April 2003

The plasma copolymerization of ethylene (ET) and tetrafluoroethylene (TFE) was investigated by means of IR and XPS analyses. The deposition rates for plasma ET/TFE copolymers, when plotted versus mol % TFE in the feed gas, gave a concave‐downward curve situated above the straight‐line joining the deposition rates for the respective plasma polymers, PPET and PPTFE, with the maximum rate at ∼ 70‐80 mol % TFE. This result, coupled with the finding that normalized absorbances of the CH and CF IR bands of ET/TFE copolymers had maxima at ∼ 20 and 80 mol % TFE, respectively, indicated a positive interaction between ET and TFE such that each monomer “sensitized” the plasma copolymerization of the other. As analyzed by XPS, CF groups dominated over CF2 and CF3 groups at 5‐70 mol % TFE, but at ≥ 80 mol % TFE, these moieties approached the relative proportions in PPTFE (CF2 > CF3 > CF). The plot of F/C ratio versus mol % TFE was concave‐upward and situated below the hypothetical straight‐line plot representing noninteracting, independent polymerization of ET and TFE, while the % F in the plasma copolymers was linear with mol % TFE. The F1s mean binding energies of the ET/TFE plasma copolymers, which increased monotonically with % F, were consistently higher than those for several commercial polymers of fluorinated olefins at comparable values of % F. This result suggested clustering of CFn moieties in the plasma copolymers or the presence of F atoms in highly fluorinated environments. © 1992 John Wiley & Sons, Inc.
Thermal oxidation of blends of poly(ethylene oxide) and poly(methyl methacrylate)
Authors: Makhija S. , Pearce E. M. , Kwei T. K.
Published: April 2003

Thermal oxidation of poly(ethylene oxide) (PEO) and its blends with poly(methyl methacrylate) (PMMA) were studied using oxygen uptake measurements. The rates of oxidation and maximum oxygen uptake contents were reduced as the content of PMMA was increased in the blends. The results were indicative of a stabilizing effect by PMMA on the oxidation of PEO. The oxidation reaction at 140°C was stopped at various stages and PMMA was separated from PEO and its molecular weights were measured by gel permeation chromatography (GPC). The decrease in the number‐average molecular weight of PMMA was larger as the content of PEO increased in the blends. The visual appearance of the films suggested that phase separation did not occur after thermal oxidation. The activation energy for the rates of oxidation in the blends was slightly increased compared to pure PEO. © 1992 John Wiley & Sons, Inc.
Optically‐active polyurethanes containing coumarin dimer component: Synthesis, characterization, and chiral recognition ability
Authors: Chen Yun , Lin Jiann‐Jang
Published: April 2003

Optically‐active polyurethanes (2a‐2c) were prepared by polyaddition reaction of diamide (1a, 1b) and diester (1c) derivatives of chiral coumarin dimer with 4,4′‐diphenylmethane diisocyanate (MDI) in chloroform and methyl ethyl ketone, respectively. The inherent viscosity of the polyurethanes are between 0.13 and 0.21 dL/g in N,N‐dimethylacetamide (DMAc) at 30°C. Treated silica gels were absorbed with ca. 25 wt % of the polyurethanes, and packed as chiral stationary phases for direct optical resolution of 16 racemates with aromatic groups by high‐performance liquid chromatography (HPLC). Polyurethanes 2a and 2b, obtained from diamide derivatives, show efficient resolution ability to some of the racemates (α = 1.06‐1.79), especially the atropic (R5) and trans (R6‐R9) isomers. The recognition ability of the polyurethanes can be attributed to the simultaneous aromatic stacking and hydrogen‐bonding interactions with racemates. © 1992 John Wiley & Sons, Inc.
Molecular weight distribution of emulsion‐polymerized polyethylene
Authors: Starkweather Howard W. , Han Mark C.
Published: April 2003

Emulsion polymerizations of ethylene were run using potassium persulfate as the initiator and either an anionic or a cationic surfactant, usually at five times the critical micellar concentration. The molecular weight distributions had at least two major peaks. The broadly distributed lower molecular weight component is formed in the early stages of polymerization. The higher molecular weight component has a narrow distribution characteristic of termination by the combination of chain radicals. The weight‐average molecular weight of this component was about 400,000 when the surfactant was sodium laurate and 33,600,000 when the surfactant was dodecyl amine hydrochloride. © 1992 John Wiley & Sons, Inc.
Shrinkage effects in photopolymerizable resins containing filling agents: Application to stereophotolithography
Authors: Karrer P. , Corbel S. , Andre J. C. , Lougnot D. J.
Published: April 2003

The influence of porous additives with various structures on the shrinkage of resins used for stereolithographic applications was studied by measuring the dependence of the specific gravity of the charged polymer material as a function of the charge fraction. The investigations were conducted on difunctional monomers photopolymerized either by a radical (acrylate) or a cationic (epoxy) mechanism. The improvement resulting from the incorporation of charges in the formulation is accounted for in a semi‐quantitative way by an adsorption‐desorption equilibrium of monomer molecules between the pores and the bulk phase. Thus, the pores of the charges which are initially filled with monomer molecules play the role of buffers which discharge their content as the photopolymerization develops in the liquid phase. It is also worth mentioning that the viscosities of the photosensitive charged resins used in these experiments are quite suitable for use in stereophotolithography. © 1992 John Wiley & Sons, Inc.
Interpenetrating polymer networks of polycarbonate‐urethane and polybutadiene
Authors: Frisch Harry L. , Zhou Peiguang
Published: April 2003

Interpenetrating polymer networks (IPN's), pseudo IPN's and linear blends of urethane‐containing aliphatic polycarbonate (PCU) and polybutadiene (PB) have been prepared and characterized. The simultaneous full IPN's of PCU and PB over the whole composition range (15‐85% by weight PCU) exhibit a single phase morphology even though the linear chain blends are completely immiscible, as determined by DSC and confirmed by transmission electron microscopy (TEM). However, in both pseudo IPN's of PCU and PB there appeared multiple (melting and glass) transitions in DSC measurements and phase separation was observed by TEM. © 1992 John Wiley & Sons, Inc.
Photocrosslinking of silicones. VI. Photocrosslinking kinetics of silicone acrylates and methacrylates
Authors: Müller Uwe , Jockusch Steffen , Timpe Hans‐Joachim
Published: April 2003

The photoinduced radical crosslinking of silicones containing pendant acrylate and methacrylate groups has been investigated with calorimetric and ESR measurements. Oxygen very strongly influences this process, which leads to a prolonged induction period and a pseudo first‐order termination reaction between polymer radicals and oxygen. Kinetically, such reaction steps are responsible for light intensity and monomer exponents, both of unity. In the absence of oxygen, second‐order processes take place between polymer and primary radicals. The results of conversion‐time and reaction‐rate time measurements using stationary irradiations and postpolymerization experiments agree with the corresponding kinetic expressions. Long‐lived polymer radicals and their decay have also been determined with ESR techniques. Long‐chain spacer groups, which link the unsaturated ester moiety at the silicone backbone, increase the crosslinking rate. The final conversions of the double bonds exceed high values in each case. © 1992 John Wiley & Sons, Inc.
Thermal degradation of poly((E,E)‐[6.2]paracyclophane‐1,5‐diene)
Authors: White Robert L. , Sikabwe Emmanuel C.
Published: April 2003

Thermal degradation of poly((E,E)‐[6.2]paracyclophane‐1,5‐diene) is studied in inert and oxidative environments by using thermogravimetric analysis, pyrolysis GC/MS, pyrolysis GC/FT‐IR, and variable temperature‐diffuse reflectance infrared spectroscopy (VT‐DRIFTS). Thermal degradation in helium begins by depolymerization yielding a volatile product capable of abstracting hydrogens from the polymer residue. Multiple hydrogen abstractions result in a variety of volatile species containing benzyl‐benzyl bonds. In the presence of oxygen, polymer decomposition is dictated by reactions of peroxy and hydroperoxy radicals. At low temperatures, oxygenated species are the primary products. At higher temperatures, increased unsaturation is detected in the polymer residue. In both inert and oxidative environments, the strain associated with alignment of paracyclophane aromatic rings is lost during the initial stages of thermal degradation. © 1992 John Wiley & Sons, Inc.
Chemical reactions occurring in the thermal treatment of polymer blends investigated by direct pyrolysis mass spectrometry: Polycarbonate/polybuthyleneterephthalate
Authors: Montaudo Giorgio , Puglisi Concetto , Samperi Filippo
Published: April 2003

The chemical reactions occurring in the thermal treatment of polycarbonate/polybuthyleneterephthalate (PC/PBT) blends have been investigated by gradual heating (10°C/min) using thermogravimetry and direct pyrolysis into the mass spectrometer. Exchange reactions occur already in the temperature range below 300°C but the transesterification equilibrium is affected by the evolution of thermal degradation products. Buthylenecarbonate, was detected in the first decomposition stage (320–380°C), which is evolved together with a series of cyclic compounds containing units of PC and PBT, in varying ratios. The overall thermal reaction evolves towards the formation of the most thermally stable polymer, i.e., a totally aromatic polyester (polymer III, Table I), which was found to be the end‐product of the thermal processes occurring in the system investigated. The thermal decomposition products obtained from the PC/PBT blends in the range 320–600°C have mass sufficiently high to be structurally significant, since they contain at least one copolymer repeating unit. The reactions occurring in the thermal treatment of the PC/PBT blend are discussed in detail. © 1993 John Wiley & Sons, Inc.
Alginate polyelectrolyte ionotropic gels. XIV. Kinetics and mechanism of formation of intermediate complex during the oxidation of alginate polysaccharide by alkaline permanganate with a spectrophotometric evidence of manganate(VI) transient species
Authors: Hassan Refat M.
Published: April 2003

The kinetics and mechanism of the [Alg.Mn VIO] intermediate complex formation during the oxidation of alginate polysaccharide at pHs ≥ 12 have been investigated spectrophotometrically. The reaction showed a first‐order dependence in permanganate and a fractional order with respect to the alginate concentration (Alg). Kinetic and spectrophotometric evidence revealed the formation of manganate(VI) as transient species. The results obtained indicated the dependence of the rate of formation on the pH of the medium where the complex formation was base catalyzed. A mechanism consistent with the experimental results is discussed. © 1993 John Wiley & Sons, Inc.
Solvent effects on the polymerization of multi‐armed vinyl biphenyl derivatives containing pendant oligo(oxyethylene)cyclotriphosphazenes
Authors: Inoue Kenzo , Nakahara Hisanori , Tanigaki Teiichi
Published: April 2003

Polymerization of vinyl biphenyl derivatives containing a pendant oligo(oxyethylene)cyclotriphosphazene (VBMEP, (OCH2CH2)nOCH3, n = 1; VBDEP, n = 2; VBTEP, n = 3) was carried out in various solvents. The conversions of these monomers increased with increasing β values, solvent hydrogen bond acceptor abilities, indicating that the hydrogen bond formation is the most important factor in the polymerization. 13CNMR study showed that the reactivity of the monomer is influenced by the hydrogen bond interaction. In ethanol, the kinetic orders of monomer and initiator concentrations for the polymerization of VBDEP were different from those in 1,2‐dichloroethane (DCE), which suggest the predominant occurrence of primary radical termination. The intrinsic viscosity of poly(VBDEP) with M̄n = 22 000 in DCE was two times higher than that in ethanol, and plots of intrinsic viscosity versus conversion of VBDEP gave a straight line. The results suggest that the polymer chains in ethanol are in a coiled conformation, whereas in DCE they are in a relatively extended structure, and that the propagation is affected by the conformational change. These behaviors originated from the hydrogen bond formation between polymers and solvents are discussed. The copolymerization of styrene with multiarmed monomers and the properties of polycascade polymers obtained are also described. © 1993 John Wiley & Sons, Inc.
Cyclopolymerization of dipropargyl isopropylidene malonate and characterization of the product
Authors: Jin Sung‐Ho , Cho Hyun‐Nam , Choi Sam‐Kwon
Published: April 2003

The polymerization of dipropargyl isopropylidene malonate (DPIPM) was polymerized by WCl6 and MoCl5 associated with various organometallic cocatalysts. MoCl5 was found to be the most effective catalyst and Ph4Sn was observed to have a high cocatalyst activity. Structure and physical properties of poly(DPIPM) were investigated. The spectral data indicated that poly(DPIPM) contains alternating double and single bonds along the polymer backbone and a cyclic recurring unit. The poly(DPIPM) was partially soluble in common organic solvents. The M̄n values of the polymer from soluble fraction were in the range of 5100–8000 relative to polystyrene standards by GPC. In addition, poly(DPIPM) possesses good stability to air oxidition. When poly(DPIPM) is exposed to iodine vapor, the electrical conductivity was increased from 4.5 × 10−11 to 7 × 10−2 S/cm. © 1993 John Wiley & Sons, Inc.
Mathematical models of the initial stage of the thermal degradation of poly(vinyl chloride). II. The thermal degradation of poly(vinyl chloride) with effective removal of HCl
Authors: Troitskii B. B. , Troitskaya L. S.
Published: April 2003

The dehydrochlorination of different samples of PVC under vacuum with continuous removal of HCl by freezing, has been studied at 180–210°C. The comparison of the kinetic curves of the dehydrochlorination of various samples of PVC which were obtained by us and other investigators, with the theoretical curves for the thermal degradation of idealized PVC in the absence of HCl has been carried out. This had made it possible to evaluate the influence of unstable fragments present in the original polymer on the initial rate of PVC degradation quantitatively. It has been shown that the distinction between the stationary rates of the dehydrochlorination of various samples of PVC is determined by the difference of the values of the average length of dehydrochlorination chain, lav. The most probable interval of the values of lav has been ascertained to be 4–12. It is established that the most probable value of the constant of the rate of dehydrochlorination of normal links of PVC, k0, is 2.1 × 10−7−2.5 × 10−7 s−1 at 200°C. © 1993 John Wiley & Sons, Inc.
Photochemically induced oxidative surface modification of polyimide films
Authors: Meier Ingrid K. , Langsam Michael
Published: April 2003

Polyimide membranes that contain both the phthalimide chromophore and abstractable hydrogens undergo photochemically‐induced oxidative surface modification when they are irradiated with ultraviolet (UV) light for 0.5–30 min in air. The reaction requires 200–300 nm light and the presence of oxygen, and the surface‐modified membranes show much higher oxygen/nitrogen selectivities than the untreated films. A mechanism for the photochemical reaction that is based on the photochemistry of structurally‐similar monomeric phthalimides is proposed. The observed selectivity increases can also be explained by this mechanism. © 1993 John Wiley & Sons, Inc.
Photochemical addition reaction of a polymer‐bearing pendant vinyl ether with various thiol compounds
Authors: Nishikubo Tadatomi , Kameyama Atsushi , Sasano Mikio , Sawada Masa‐Aki
Published: April 2003

Photochemical addition reaction of the pendant vinyl ether group in the polymer (P‐1), which was synthesized by the alternate ring‐opening copolymerization of glycidyl vinyl ether with phthalic anhydride, with various thiol compounds such as benzenethiol, phenylmethanethiol, 2‐mercaptoacetic acid, ethyl 2‐mercaptoacetate, N‐acetyl‐L‐cysteine (AcCys), and 1,4‐phenylenedi(methylthiol) was carried out using benzophenone (BP) as the photosensitizer in the THF solution. Each reaction proceeded very smoothly to give the corresponding polymers with high conversion, although the degree of reaction of the pendant vinyl ether group in P‐1 was affected by the molar ratio between the thiol compounds and the vinyl ether group, and the amounts of photosensitizer BP added. Furthermore, it was also found that optically active polymer containing pendant N‐acetyl‐L‐cysteine residue was synthesized by the photochemical addition reaction of P‐1 with AcCys. The reactions of P‐1 with dithiol or bisazide compounds occurred effectively to give gel products in the film state, and it was found that the polymer film containing P‐1 and those compounds can be applied as negative‐type photoresists with high practical photosensitivity. © 1993 John Wiley & Sons, Inc.
Synthesis and gas transport properties of high molecular weight block copolymers of styrene and vinyltrimethylsilane
Authors: Rickle Greg K.
Published: April 2003

Poly(styrene‐b‐vinyltrimethylsilane) of high molecular weight and varying composition suitable for membrane applications has been synthesized at 50–60°C. The copolymer could be made as a tapered block copolymer by polymerizing both monomers at the same time (r1 and r2 = 0.08 and 13) or as a pure block copolymer with some homopolymer contaminant by sequential addition of monomers. However, in both methods the copolymer phases out of solution before the reaction is complete. The copolymers can exhibit phase separation in the solid and dissolved states. Poly(styrene‐b‐vinyltrimethylsilane) membranes have some unique gas transport properties. The poly(vinyltrimethylsilane) segments are phase separated and dispersed in a continuous polystyrene matrix so the resultant membranes can have over twice the permeability of polystyrene but also retain the high selectivity of polystyrene. These results should be applicable to other biphasic systems where the low permeability phase is also the continuous phase. © 1993 John Wiley & Sons, Inc.
Thermal stability of modified telechelic polystyrenes
Authors: Charlier Pascal , Jérome Robert , Teyssié Philippe , Proud'Homme Robert E.
Published: April 2003

The thermal stability of telechelic polystyrenes bearing quaternary ammonium iodide or ammonium sulfonate end groups is presented. It appears that the ammonium iodide functions are stable below 200°C. Above that temperature, the polystyrene irreversibly looses its functional end groups. The weight loss then observed leads to the conclusion that a Hofmann‐type degradation mechanism is likely to take place. In contrast, the ammonium sulfonate‐terminated polystyrene begins to degrade at 180°C and leads to a polymer which is no longer end‐capped with sulfonic acid or sulfonate groups. This behavior is of importance, especially for the study of multiblock ionic copolymers which are prepared by blending two telechelic polymers, one of them bearing sulfonic acid end groups and the other one tertiary amine functional groups. © 1993 John Wiley & Sons, Inc.
Synthesis and thermal properties of aryl‐substituted rod‐like polyimides
Authors: Giesa Reiner , Keller Uwe , Eiselt Petra , Schmidt Hans‐Werner
Published: April 2003

This article describes the synthesis and thermal characterization of novel aryl‐substituted rod‐like homopolyimides. Synthetic aspects of monomer syntheses and one‐step polymer synthesis in m‐cresol are presented. Polyimides with rod‐like chain structure are based on monophenylated pyromellitic dianhydride (MPPMDA), diphenylated pyromellitic dianhydride (DPPMDA), and as rod‐like diamine units on phenylated para‐phenylene diamine and 1,1′‐binaphthyl‐4,4′‐diamine. As partial flexible units, which have the possibility to be converted into an extended chain conformation, commercially available 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (BPDA) and 3,4′‐oxydianiline (3,4′‐ODA) were used. The polyimides were investigated with respect to solution properties and thermal behavior. © 1993 John Wiley & Sons, Inc.
Photochemical behavior of p‐dimethylaminobenzoylated polystyrene as polymerization photoinitiator: Synthesis of graft copolymers
Authors: Mateo J. L. , Bosch P. , Catalina F. , Sastre R.
Published: April 2003

The photochemical behavior of p‐dimethylaminobenzoylated polystyrene (PS‐MI) in benzene solution has been investigated, both in the presence and absence of methyl methacrylate (MMA). This behavior has been compared with that of the model compound, 4‐isopropyl‐4′‐N,N‐dimethylaminobenzophenone (CU‐MI). PS‐MI photoreduction takes place only through excimer formation due to the high local chromophore concentration, and therefore, PS‐MI disappearance quantum yield is close to the previously calculated limiting value (0.02) and independent of chromophore concentration. Several parameters that characterize the polymerization process have been determined; it has been found that the obtained PMMA is photografted onto PS‐MI backbone. This is in agreement with the proposed mechanism for radical generation. No homo‐PMMA formation has been detected. © 1993 John Wiley & Sons, Inc.
A study of polyurethanes synthesized from an arylsilane, bis(4,4′‐phenylisocyanato)dimethylsilane, and its carbon analog, 2,2‐bis(4,4′‐phenylisocyanato)propane
Authors: Thames S. F. , Malone K. G.
Published: April 2003

Bis(4,4′‐phenylisocyanato) dimethylsilane (SiDI) and 2,2‐bis (4,4′‐phenylisocyanato)propane (PrDI) were synthesized, polymerized to polyurethanes, and their chemical, thermal and physical properties studied. Nuclear magnetic resonance spectra confirm deshielding by silicon of both the phenyl ring and the urethane linkage. The glass transition temperatures, solubility parameters, and mechanical properties were independent of the diisocyanates. The silicon containing polyurethanes are more thermally stable than their carbon counterparts. © 1993 John Wiley & Sons, Inc.
Kinetic studies of photopolymerization using real time FT‐IR spectroscopy
Authors: Yang D. Billy
Published: April 2003

The real time FT‐IR (RT/FT‐IR) technique has been recognized as a very vital tool to quantitatively study the curing parameters such as the effects of initiator (or catalyst) type and concentration, accelerator, stabilizer, irradiation wavelength, temperature, and curing environments. Herein, our results in studies of photoinduced polymerizations for adhesive and coating applications are reported. The photoinduced polymerizations studied included anionic and hydrosilation (a polyaddition polymerization) reactions. In photoinduced anionic polymerization our studies for ethyl cyanoacrylate polymerization are described. The effect of the concentration of photoinitiator and inhibitor on the ethyl cyanoacrylate polymerization kinetic rate will be discussed. In photoinduced catalytic hydrosilation reaction studies, the effects of the catalyst concentration and staging irradiation are disclosed. The hydrosilation reaction was monitored using a SiH silicone hydride stretching band located at 2169 cm−1. The cyanoacrylate polymerization was monitored using the CC stretching band occurring at 1617 cm−1. The hydrosilation conversion was completed with an appropriate formulation. For monofunctional cyanoacrylate monomer, the photoinduced conversion to straight chain polymer was approximately 85% for a 60 s period. The intrinsic rates of the reactions were calculated for kinetic comparisons. For very fast cyanoacrylate polymerization studies, new FT‐IR kinetic software was used to collect 204 spectra/min. Some detailed experimental techniques and polymerization reaction mechanisms are also discussed. © 1993 John Wiley & Sons, Inc.
Polymerization of ethylene using a high‐activity Ziegler–Natta catalyst. I. Kinetic studies
Authors: Marques Maria M. V. , Nunes Clemente Pedro , Tait Peter J. T. , Dias Alberto Romão
Published: April 2003

Factors affecting the particular shape of kinetic rate–time profiles in the polymerization of ethylene with a MgCl2‐supported TiCl4catalyst activated by Al(C2H5)3have been investigated. Examination of the dependence of the polymerization rate on the concentration of Al(C2H5)3resulted in a Langmuir–Hinshelwood rate law. Analysis of the polymerization rate as a function of the polymerization temperature gave about 46 kJ mol−1for the overall activation energy. Examination of the rapid decay of the polymerization rate with time showed that this decay is represented better by a first‐order decay law than by a second‐order one. © 1993 John Wiley & Sons, Inc.
Ethylene–hexene copolymerization by heterogeneous and homogeneous Ziegler–Natta catalysts and the “comonomer” effect
Authors: Chien James C. W. , Nozaki Takashi
Published: April 2003

Homopolymerization of ethylene and 1‐hexene and their copolymerizations were compared to investigate the influence of α‐olefin on the enhancement of ethylene polymerization rate (Rp), which is often referred to as the “comonomer” effect. With the two homogeneous Ziegler–Natta catalysts, Et[Ind]2ZrCl2/MAO and (π‐C5H5)2ZrCl2/MAO (MAO = methylaluminoxane), hexene causes reduction of Rp—in other words a negative “comonomer” effect. In the case of the high activity MgCl2 supported TiCl3 catalysts there is a slight positive “comonomer” effect; the Rp increases by 25 to 70% with the addition of 15 mol % of hexene. The “comonomer” effects in there catalyst systems are much smaller than that observed for the classical TiCl3 catalyst. © 1993 John Wiley & Sons, Inc.
Amino acid end‐group in commercial heparin. III. Determination of the number of amino groups of amino acid and hexosamine residues per heparin molecule
Authors: Arai Kozo , Matsunaga Atsushi , Yoneyama Masaru , Takigami Shoji , Nakamura Yoshio , Edwards Haydn E. , Phillips Glyn O.
Published: April 2003

The reactions of heparin with 2,4,6‐trinitrobenzenesulfonic acid (TNBS) were studied spectrometrically. Seven different commercial heparins were used in this study. The amino groups react with TNBS to form equimolar amounts of trinitrophenylated (TNP) amino groups and bisulfite ions. The TNP‐amino groups further react with bisulfite ions to form the monosubstituted anionic sigma complex. The absorption spectrum with two maxima at approximately 350 nm and approximately 420 nm, characteristic of either the TNP‐amino groups or the complex, was analyzed for the reaction of TNBS with heparin. It was shown that the reactivities of TNBS with amino groups from α‐amino acid and hexosamine residues are greatly different. By combining the results of the reaction kinetics and the reaction of heparin with Sanger's reagent, the number of the α‐amino groups and the free amino groups in hexosamine residues were determined. These data have been performed with a range of heparins from different commercial sources, of different activities and physical characteristics. No correlation was found between the free amino contents of these heparins and biological potency. © 1993 John Wiley & Sons, Inc.
Copolymerization of carbon monoxide with 1,3‐cyclopentadiene by palladium complexes
Authors: Liaw Der‐Jang
Published: April 2003

Copolymerization of carbon monoxide with 1,3‐cyclopentadiene (CPD) by palladium complexes, [Pd(CH3CN)4−n (PPh3)n] (BF4)2, n = 1–3 (especially n = 1), was studied at 60°C. Results of elementary analysis, infrared spectra, and NMR spectra showed that copolymers containing ketone and ring structures were produced. Phosphorus compounds such as PPh3 were found to be more effective stabilizing ligands for the catalytic activity compared to arsenic or nitric ligands. A higher activity of the catalyst for the copolymerization of CPD with carbon monoxide was observed in noncoordinating solvents such as CHCl3 even at a pressure as low as 300 psi. The amount of 1,2 structure for the CPD‐CO copolymer increased as the polarity of solvent increased. The copolymer was confirmed to be partially crystalline by the x‐ray diffraction. TGA shows that weight loss of copolymer starts at 120°C and the maximum peak of decomposition occurs at 469°C. © 1993 John Wiley & Sons, Inc.
Triphase catalysis. II. Alkylation of phenylacetone with 1‐bromobutane catalyzed by aqueous NaOH and polystyrene‐supported benzyltriethyl ammonium chloride
Authors: Balakrishnan T. , Babu S. Hari , Shabeer T. K.
Published: April 2003

Insoluble microporous polystyrene‐bound benzyltriethyl ammonium chloride has been used as a catalyst in the alkylation of phenylacetone with 1‐bromobutane, and the kinetics of this reaction was investigated under phase‐transfer catalytic conditions. The observed reaction rates depend on many experimental parameters, viz., stirring speed, substrate amount, basicity of aqueous NaOH, amount of 1‐bromobutane, temperature, order of addition of the reactants and particle size, percent active site, and percent crosslinking of the polymer. The rates are nearly 12 times higher at lower concentrations of base than at higher concentrations and do not vary appreciably with a variation in stirring speed from 200 to 700 rpm. The rate of alkylation increases with a decrease in the particle size of the catalyst and crosslinking of the polymer. Based on the results obtained, a suitable mechanism in which a combination of intraparticle diffusion and intrinsic reactivity limit the reaction rates has been proposed. © 1993 John Wiley & Sons, Inc.
Miscibility of poly(vinyl methyl ether) and poly(styrene‐co‐2‐vinylnaphthalene) blends by FT‐IR spectroscopy and Tg measurements
Authors: Ryou Jin Ho , Ha Chang Sik , Cho Won Jei
Published: April 2003

Miscibility of blends consisting of poly(vinyl methyl ether) (PVME) and poly(styreneco‐2‐vinylnaphthalene) [P(S‐co‐2VN)] was investigated by means of Fourier transform infrared (FT‐IR) spectroscopy and thermal analysis. Copolymers containing 21, 51, and 84 wt % of styrene were synthesized by radical polymerization. Based on optical clarity and glass transition temperatures, it was shown that the miscibility in P(S‐co‐2VN)/PVME blends is largely affected by compositions of the copolymers as well as concentrations of the blend. From the FT‐IR results, the relative intensity at 1100 cm−1 peak of COCH3 band of PVME and the position of naphthyl ring of 2VN were sensitive to the miscibility of the blends. It was observed that blends of PVME with P(S‐co‐2VN) of 84 wt % styrene or P(S‐co‐2VN) of 51 wt % styrene are miscible over the entire concentration ranges of the blends. Blends of PVME with P(S‐co‐2VN) containing 21 wt % of styrene are immiscible below 65 wt % PVME. In the miscible P(S‐co‐2VN)/PVME blends, there was observed a large shift in the naphthyl frequency at a characteristic wavelength of 748 cm−1. © 1993 John Wiley & Sons, Inc.
Synthesis and properties of poly(dipropargyl sulfoxide)
Authors: Gal Yeong‐Soon , Choi Sam‐Kwon
Published: April 2003

The preparation and cyclopolymerization of dipropargyl sulfoxide were studied. The polymerization of dipropargyl sulfoxide was carried out by various transition metal catalysts. WCl6–EtAlCl2, MoCl5, and PdCl2 catalyst systems were very effective. The resulting poly(dipropargyl sulfoxide) structures were characterized by NMR (1H and 13C), IR, and elemental analysis to have conjugated polyene units. Poly(dipropargyl sulfoxide) prepared by PdCl2 was mostly soluble in organic solvents such as DMF and DMSO. Thermal and oxidative properties of poly(dipropargyl sulfoxide) were also studied. The electrical conductivity of iodine‐doped poly(dipropargyl sulfoxide) was 5.2 × 10−2 Ω−1 cm−1. Comparisons of poly(dipropargyl sulfoxide) properties with other similar polymers from dipropargyl sulfur derivatives such as dipropargyl sulfide and dipropargyl sulfone were also carried out. © 1993 John Wiley & Sons, Inc.
Studies of reactions with polymers. VII. The reaction of acrylonitrile‐grafted polyvinyl alcohol copolymer (PVA‐g‐AN) with NaOH/HCHO aqueous solution
Authors: Chiang Wen‐Yen , Huang Ching‐Chong
Published: April 2003

The reaction mechanism of acrylonitrile (AN)‐grafted polyvinyl alcohol (PVA) with NaOH/HCHO aqueous solution was studied. It was found that intermolecular reactions occur between the nitrile groups in PAN side chains with formaldehyde initiated by sodium hydroxide. The resultant structure proposed is based on IR analysis and elemental analysis of the composition before and after NaOH/HCHO treatment. Its thermal properties of modified membranes were also determined. © 1993 John Wiley & Sons, Inc.
Aggregational behavior in water, of some polyamphiphiles derived from reactive polymers
Authors: Tsiourvas Dimitris , Paleos C. M. , Malliaris Angelos
Published: April 2003

Selected polyamphiphiles were prepared by the method of reactive polymers, i.e., interaction of polymaleic anhydride and polyacryloyl chloride with certain long chain alcohols. The aggregational behavior of these polyamphiphiles in water was studied by video‐enhanced differential interference contrast microscopy, as well as by absorption and fluorescence spectroscopy. The formation of large aggregates was observed by video technique, while inter‐ and intramolecular micelles were detected by spectroscopic © 1993 John Wiley & Sons, Inc.
Effect of substitution on the reactivity of some new p‐phenylacrylamide derivatives with organotin monomers
Authors: Tawfik S. Y. , Messiha N. N. , El‐Hamouly S. H.
Published: April 2003

Three new monomers of p‐phenylacrylamide derivatives were prepared by either the reaction of p‐methyl‐, p‐nitro‐, and p‐chloroaniline with acryloyl chloride or with acrylic acid in the presence of dicyclohexyl carbodiimide (DCCI). The prepared monomers were copolymerized with each of tri‐n‐butyltinacrylate and tri‐n‐butyltinmethacrylate. Copolymerization reactions were carried out in dioxane at 70°C using 1 mol % azobisisobutyronitrile as a free radical initiator. The structure of the new monomers and the prepared copolymers were investigated by IR and 1H‐NMR spectroscopy. The monomer reactivity ratios for the copolymerization of p‐chlorophenylacrylamide (M1) with each of tri‐n‐butyltinacrylate (TBTA) and tri‐n‐butyltinmethacrylate (TBTMA) (M2) were found to be r1 = 2.6; r2 = 0.83 and r1 = 1.3; r2 = 1.71, respectively. In case of p‐tolyacrylamide (M1) with TBTA and TBTMA (M2) r1 = 0.35, r2 = 1.03 and r1 = 1.38, r2 = 0.366 respectively. The Q and e values for the prepared p‐tolyl‐ and p‐chlorophenylacrylamide were calculated © 1993 John Wiley & Sons, Inc.
Synthesis of poly(2‐cyclohexenone‐4‐yl methacrylate) and acidolysis of pendant protecting groups in the polymer
Authors: Iizawa Takashi , Nishiyama Kazuaki , Nishikubo Tadatomi
Published: April 2003

4‐Acetoxy‐2‐cyclohexenone (ACH) and 2‐cyclohexenone‐4‐yl methacrylate (CHM) were obtained from the condensation reaction of 4‐bromo‐2‐cyclohexenone (BCH) with acetic acid and methacrylic acid using 1,8‐diazabicyclo‐[5,4,0]‐7‐undecene (DBU), respectively. Poly(2‐cyclohexenone‐4‐yl methacrylate) (P‐1) containing acid‐sensitive 2‐cyclohexenone‐4‐yl group was prepared from the radical polymerization of CHM and the esterification of poly(methacrylic acid) with BCH using DBU. Furthermore, P‐1 and CHM copolymers (P‐2 and P‐3) were easily synthesized from the radical polymerization of methacrylic acid and comonomers in dimethylsulfoxide using 1 mol % of 2,2′‐azobis (isobutyronitrile) followed by esterification of the resulting polymers with BCH using DBU by one‐pot method. The deprotection reaction of ACH and P‐1 was carried out in dichloromethane using an acid catalyst. The reaction proceeded smoothly in solution to give phenol and the corresponding carboxylic acid. Therefore, the 2‐cyclohexenone‐4‐yl group is a useful protecting group for carboxylic acids, because the protection and deprotection reactions are very easy. In the case of polymer films, however, the acid was trapped by carbonyl group on the 2‐cyclohexenone‐4‐yl group, and did not cause the deprotection reaction. © 1993 John Wiley & Sons, Inc.
Polyesterification reactions of adipic acid‐based polyesters
Authors: Chang Wally L. , Karalis Tom
Published: April 2003

A series of studies of uncatalyzed and catalyzed polyesterification experiments have been investigated using different glycols at different temperatures. The experimental results for uncatalyzed reactions agreed quite well with the kinetic equation as proposed by P. J. Flory. However, Flory proposed a second‐order reaction for an externally added strong acid as a catalyst. In contrast to Flory's theory, a mixed mechanism, based on a combination of carboxylic acid groups from the raw material and an external organotin catalyst, was proposed for the catalyzed reaction. In this article, the reaction rate of catalyzed and uncatalyzed polyesterifications using different glycols was compared, and the effect of different temperatures and catalyst levels was also discussed. The reaction rate constant decreases in the following order for both catalyzed and uncatalyzed polyesterification: 1,6‐HD > 1,4‐BD > NPG > DEG > EG ≫ PG. © 1993 John Wiley & Sons, Inc.
Macromolecular engineering of polylactones and polylactides. X. Selective end‐functionalization of poly(D,L)‐lactide
Authors: Barakat I. , Dubois Ph. , Jérôme R. , Teyssié Ph.
Published: April 2003

Functional aluminum alkoxides, such as Et3–pAl(OCH2X)p, where p = 1,3 and X = a functional group, are very effective initiators for the (D, L)‐lactide polymerization in toluene at 70°C. The coordination‐insertion type of polymerization is living. Linear polyesters of a predictable molecular weight and a narrow molecular weight distribution are obtained within the period of time required for the total monomer conversion. The functional group (X) associated with the active alkoxy group of the initiator is selectively and quantitatively attached to one chain end, whereas the second end group is systematically a hydroxyl function resulting from the hydrolysis of the living growing site. Asymmetric telechelic polylactides are thus obtained in a perfectly controlled way. A kinetic study has shown that the polymerization is first order in both the monomer and initiator. © 1993 John Wiley & Sons, Inc.
Radiation‐induced graft polymerization of acrylic acid onto fluorinated polymers. II. Graft copolymer–metal complexes obtained by radiation grafting onto poly(tetrafluoroethylene‐ethylene) copolymer
Authors: Hegazy El‐Sayed A. , Dessouki Ahmed M. , El‐Sawy Naeem M. , Abd El‐Ghaffar Mahmoud A.
Published: April 2003

A study has been made on the graft copolymers obtained by radiation‐induced grafting of acrylic acid onto poly(tetrafluoroethylene‐ethylene) (ET) films. The conversion of the graft copolymer into metal acrylate copolymer complex was carried out by treatment with different metal salts. Such a prepared graft copolymer–metal complex was confirmed by different methods: IR, UV spectrometry, degree of coloration, and x‐ray fluorescence. Some selected properties of the graft copolymer–metal complexes such as electrical conductivity, swelling behavior, and mechanical properties were investigated. The influence of metal complexes in the graft copolymers was determined and compared with the grafted films. The possibility of the practical uses for such prepared graft copolymer–metal complexes was discussed and determined. It was assumed that such materials may be of great interest in the field of semiconducting materials in addition to their applicability as cation‐exchange membranes. © 1993 John Wiley & Sons, Inc.
Formation of aromatic polyetherketone and trans‐etherification of aromatic polyetherketone
Authors: Fukawa Isaburo , Tanabe Tsuneaki
Published: April 2003

High molecular weight aromatic polyetherketone (PEK) was found to react with 4,4′‐difluorobenzophenone (DFB) in the presence of potassium carbonate in benzophenone or diphenyl sulfone at 300°C, yielding low molecular weight PEK with fluorophenyl end groups, while neither polyetheretherketone (PEEK) nor poly‐thioetheretherketoneketone was found to react under similar conditions. Reaction model experiments showed that 4‐fluoroben‐zophenone reacts with potassium carbonate at 300°C to yield benzoyldiphenyl ether and that benzoyldiphenyl ether undergoes spontaneous trans‐etherification in the presence of potassium carbonate at 300°C. These results indicate that the overall reaction yielding PEK of reduced molecular weight consists essentially of DFB oligomerization followed by trans‐etherification between the DFB oligomer and PEK. © 1993 John Wiley & Sons, Inc.
Modification of polybenzimidazole: Synthesis and thermal stability of poly(N1‐methylbenzimidazole) and poly(N1,N3‐dimethylbenzimidazolium) salt
Authors: Hu Ming , Pearce Eli M. , Kwei T. K.
Published: April 2003

Poly(N1,N3‐dimethylbenzimidazolium) (PDMBI) salt and poly(N1‐methylbenzimidazole) (PMMBI) were synthesized by methylation of commercial polybenzimidazole [poly‐2,2′‐(m‐phenylene)‐5,5′‐bibenzimidazole (PBI)]. First, the N‐lithium salt of polybenzimidazole was formed by treating polybenzimidazole solution of 1‐methyl‐2‐pyrolidinone (NMP) with lithium hydride at 80°C for 18 h. Ninety percent substitution of PMMBI was obtained by treating the N‐lithium salt of PBI with equimolar ratio of iodomethane at room temperature. Upon addition of excess iodomethane to the lithium salt of PBI at 80°C, a polymer was formed that showed 100% substitution on the N1 nitrogen and about 30% substitution of the methyl group on the N3 nitrogen in the form of N1,N3‐dimethylbenzimidazolium iodide salt [PDMBI (30%)]. The content of the benzimidazolium iodide salt was increased to about 90% by dissolving PDMBI (30%) in dimethyl sulfoxide (DMSO) and re‐treating with excess iodomethane at 80°C overnight. The modified PBI polymers were characterized by NMR and FTIR. The modified PBI differed in solubility from PBI. PMMBI could be easily dissolved in NMP and PDMBI in DMSO at room temperature. The solution of PDMBI could be mixed with water in all proportions without precipitation. PDMBI could be also dissolved directly in a mixture of DMSO and water (1 : 1). Typical polyelectrolyte behavior of viscosity was found in solution of PDMBI (30%) and PDMBI (90%) when DMSO and a mixture of DMSO and water were used as solvents. A salt effect on viscosity was also found in the mixed solvent solution. Thermogravimetric analysis (TGA) showed that the methyl group on the imidazole ring was unstable above 180°C under nitrogen. When PDMBI was heated under nitrogen, one of the methyl groups was lost with the counterion to result in a neutral PMMBI. © 1993 John Wiley & Sons, Inc.
Copolymers of PBT and nylon 4T
Authors: Gaymans R. J. , De Haan J. L. , Van Nieuwenhuize O.
Published: April 2003

Polybutylene terephthalate–nylon 4T copolymers (PBT–PA 4T) are synthesized from the diamide of diaminobutane and dimethyl terephthalate (DMT) with butane diol and more DMT in a concentration range of up to 50% PA 4T. The polymerization conditions were similar to those for PBT: first, a melt polymerization, followed by solid‐state post‐condensation. The materials were studied by differential scanning analysis (DSC) (melting and crystallization behavior) and dynamic mechanical thermal analysis (DMTA) (glass transitions and torsion moduli). The water absorptions were determined at 100% RH. By increasing the PA 4T content in the copolymers, melting temperatures increased strongly, heats of fusion decreased slightly, and glass transition temperatures increased linearly. The torsion moduli above the glass transition temperature were higher. © 1993 John Wiley & Sons, Inc.