bluuebunny/crossref_metadata_2025 huggingface dataset:
Modification of catalysts for propylene polymerization: Alcohols and lewis bases
Authors: Sivak A. J. , Kissin Y. V.
Published: April 2003

A series of compounds were examined as modifiers for the high activity supported catalyst TiCl4/MgCl2–AlEt3 for isospecific propylene polymerization. The list included two aromatic acid esters, 21 various Lewis bases, and 12 alcohols. A convenient graphic method is described for comparing the performance of different modifiers by plotting experimental results in coordinates “relative activity‐isotactic index” and a kinetic rationale for this evaluation is presented. Aromatic acid esters exhibit much better performance than the bulk of Lewis bases but some sterically demanding aromatic alcohols show behavior show similar to that of the esters.
Thermal analysis of the pyrolytic behaviors of a highly crosslinked polymer
Authors: Tou James C.
Published: April 2003

Thermogravimetric‐mass spectrometric (TG/MS) and differential scanning calorimetric (DSC) techniques were used in the characterization of oxidative and nonoxidative degradation reactions of a highly crosslinked divinylbenzene/styrene copolymer. When the copolymer was subjected to a temperature‐programmed air environment, four exothermic reactions were detected. The initial small exothermic reaction, starting at ca. 125°C and reaching its maximum at ca. 180°C, was presumed to result from the decomposition of peroxides. The second exothermic reaction, which overlapped with the initial one and peaked at ca. 270°C, was attributed to oxidation with a significant amount of oxygen uptake and liberation of some gaseous products such as CO2, styrene, benzaldehyde, ethylstyrene, and ethylbenzaldehyde. The strongest exothermic reaction took place at ca. 290–380°C and had its peak at ca. 360°C. Associated with this reaction was the generation of many gaseous pyrolysates, as given above. The exothermic reaction continued at a relatively constant rate from ca. 380°C to the maximum temperature of the experiment (500°C) with the release of only one gaseous product (CO2). The initial exothermic reaction can be eliminated by controlled thermal decomposition of peroxides; therefore, a more thermally stable polymer can be obtained. Exothermic reactions, starting at ca. 170°C, were observed. Pyrolytic reactions in an inert gas were also studied.
Intrinsic reactivity of active species in Ziegler–Natta polymerization of ethylene initiated with Li/Ti‐based macromolecular complexes
Authors: Siove Alain , Fontanille Michel
Published: April 2003

Polymerization of ethylene was initiated with soluble polystyrene100‐butadiene3‐Li/TiCI4 complexes in toluene leading to block copolymers. The activity of the system was measured at a constant ratio r = [Li]/[Ti] and for different concentrations in active centers and in monomer. Measurement of the amount of the block copolymers formed led to the direct determination of the efficiency of the catalytic system. This efficiency is defined with respect to the number of potentially active centers and is close to 90%. From both measured values of activity of the catalytic system and of its efficiency, the rate constants of propagation were deduced. The kinetic behavior of the system is fully consistent with that of a living system. The rate is first order towards both ethylene and active centers concentrations. So, the rate constant of propagation is an absolute rate constant, measuring the intrinsic reactivity of active sites. Determination of the absolute rate constant at different temperatures, led to thermodynamic parameters of the propagation reaction. The chemical composition of the complex and the absence of polymeric aggregation, leads to propose a structure of the active species: a bioctahedral binuclear structure is consistent with kinetic, thermodynamic results, and structural determinations.
Modelization of photocatalyzed oxidation of polyolefins. II. ZnO and TiO2 photocatalyzed decomposition of tert‐butyl hydroperoxide and atactic polypropylene hydroperoxides
Authors: Lacoste Jacques , Arnaud Rene , Lemaire Jacques
Published: April 2003

Direct evidence of the TiO2 and ZnO photocatalytic decomposition of tert‐butyl hydroperoxide and atactic polypropylene hydroperoxides in solution is reported. Molecular and macromolecular hydroperoxides behaved similarly. Untreated TiO2 in the rutile form was a far more efficient photocatalyst than ZnO in solution; the photoactivities of both pigments were limited on preferential absorption sites. In the solid state no preferential reaction sites were observed. When added to preoxidized atactic polypropylene both pigments were photocatalysts of the formation of macromolecular hydroperoxides and of their decomposition. The photoreactivities of untreated TiO2 and ZnO varied less than in solution.
Partitioning of polystyrene between incompatible phases and distributional effects in the system polystyrene–polybutadiene–toluene
Authors: Narasimhan Venkataraman , Huang Robert Y. M. , Burns Charles M.
Published: April 2003

The average molecular weights and the molecular weight distributions of polystyrene (PS) in the conjugate incompatible phases of the ternary system of PS and polybutadiene with toluene as solvent were studied at 23°C. Gelpermeation chromatography, with ultraviolet and differential refractive index detectors, was used for analyzing the compositions of the conjugate phases and for obtaining the molecular weight averages of PS in the phases. Both narrow and broad molecular weight distribution (MWD) polymer samples were used. The effect of broad MWD polymers is seen as one of narrowing the shape of the binodal, thus effectively increasing the compatible region. The molecular weight averages of PS in the two conjugate phases do not vary significantly in the case of the narrow MWD PS sample while for broad MWD samples the average molecular weight of PS is found to be higher in the PS‐rich phase than in the polybutadiene‐rich phase for tie lines closer to the plait point indicating a partitioning or redistribution of the molecular weight species of PS between the incompatible phases.
Sulfonation chemistry of some small molecule models of EPDM rubbers. II. The structure of intermediate adducts
Authors: Thaler Warren A. , Dubreuil Catherine
Published: April 2003

As previously reported, our initial investigation was concerned with the bicyclic olefins, ethylidene norbornane, and dihydrodicyclopentadiene. The former produced a skeletally rearranged γ‐sultone and the latter an allylic sulfonic acid. In an attempt to further clarify the mechanisms of the sulfonation of these two models and to extend the study to models of other types of EPDM, we have now examined the sulfonation of several other model olefins. In addition to the bicyclic olefins reported previously, we have studied the sulfonation of monocyclic type II and III olefins and cyclic type I and type II olefins. The results showed that the bicyclic olefins behaved differently from their monocyclic analogs reinforcing earlier speculation as to a synchronous reaction mechanism. Exocyclics gave allylic sulfonic acids while endocyclics produced β‐sultones, which is the exact reverse of what was observed for the bicyclic counterparts. Acyclic type II olefins produced “stable” β‐sultones, and the influence of the sulfonating reagent on the subsequent chemistry is discussed. Type I olefins, curiously, gave a complex mixture of initial products which tended to rearrange to essentially a single thermodynamic product. The results of the investigation suggest that based on these models, each of the three major types of EPDM should have a different sulfonation mechanism.
Synthesis of high‐molecular‐weight poly(amide‐ester)s by direct polycondensation with diphenyl chlorophosphate
Authors: Higashi Fukuji , Hoshio Atsushi , Ohtani Hiroshi
Published: April 2003

High molecular weight aromatic poly(amide‐ester)s were prepared by the direct polycondensation reactions between aromatic dicarboxylic acids and aminophenols under mild conditions in pyridine. The condensing agents examined in this study were diphenyl chlorophosphate (DPCP), DPCP/LiCl, and DPCP/DMF. Addition time of the aminophenols, depending on their nucleophilicities, affected the ηinh values and monomer sequence of the resulting polymer. Their thermal properties were studied in terms of the sequences in the polymer backbones.
Preparation and hydrogenation studies of rhodium(I) catalyst supported on polymer crystal surfaces
Authors: Iii Bernard Gordon , Butler Jacqueline S. , Harrison Ian R.
Published: April 2003

In recent years polymers have been utilized as binding sites for transition metal catalysts (e.g. crosslinked polystyrene beads). However, general problems exist with the above system. The rate of reaction depends on the presence of solvents that adequately swell the polystyrene bead in order to allow access to the catalytic sites. Differences in polarity and reactant size can inhibit diffusion into the bead. Recently a new system has been developed whereby tris(triphenyl phosphine) chlororhodium (Wilkinson's catalyst) is bound to the surface of polyethylene single crystals. Polyethylene single crystals have a very high surface to volume ratios allowing for greater ease of reaction compared to the polystyrene system. Diffusion control of the reactant poses no problem as the catalyst is bound to the surface of the crystal rather than the interior (as in the case of polystyrene beads). In addition, many solvents can be used due to the difficulty of dissolving crystalline polyethylene (except at high temperatures). The polyethylene crystals were tested for their catalyst content using neutron activation analysis. Test results showed 3.11 wt% catalyst present on the surface of the PE single crystals. Hydrogenation studies have been conducted using the PE supported catalyst system to show the potential effectiveness of the new system.
Plasma polymerization investigated by the substrate temperature dependence
Authors: Yasuda H. , Wang C. R.
Published: April 2003

Plasma polymerization of tetra fluoroethylene (TFE), perfluoro‐2‐butyl‐tetrahydrofuran (PFBTHF), ethylene, and styrene were investigated in various combinations of monomer flow rates and discharge wattages for the substrate temperature range of −50 to 80°C. The polymer deposition rates can be generally expressed by k0 = Ae−bt, where k0 is the specific deposition rate given by k0 = (deposition rate)/(mass flow rate of monomer), A is the preexponential factor representing the extrapolated value of k0 at zero absolute temperature, and b is the temperature‐dependence coefficient. It was found that the value of b is not dependent on the condensibility of monomer but depends largely on the group of monomer; that is, perfluorocarbons versus hydrocarbons. The values of A are dependent on domains of plasma polymerization. In the energy deficient region A is given by A = α(W/FM)n, where α is the proportionality constant, W is discharge wattage, FM is the mass flow rate, and n is close to unity. In the monomer deficient region A becomes a constant. The kinetic equation is discussed in view of the bicyclic rapid step‐growth polymerization mechanisms.
Complexation of poly(ethyleneimine) with copper(II) and nickel(II) ions in 0.5 M KNO3 solution
Authors: Fujimori Kiyohisa
Published: April 2003

Complexation of poly(ethyleneimine) (PEI) with copper(II) and nickel(II) ions was studied in a 0.5M aqueous KNO3 solution. The potentiometrically determined logarithm of the three successive formation constants (log kJ) were 8.14, 7.96, and 7.37 for Cu+2‐PEI complexation and 6.74, 6.52, and 6.23 for Ni+2–PEI complexation at 25°C, according to Bjerrum's modified method. The maximum average coordination number was 3.2 for the Cu+2–PEI system and 3.7 for the Ni+2–PEI system. An entropy effect was observed in the third coordination. The wavelengths of maximum absorption of the complexes and the continuous variation method showed that at least two coordination sites of Cu+2 ion and three coordination sites of Ni+2 ion were occupied immediately by PEI as the solutions of PEI and the metal ions were mixed.
Microstructural order in the developing cotton fiber based on availabilities of hydroxyl groups
Authors: Rowland Stanley P. , Howley Phyllis S.
Published: April 2003

The relative availabilities of accessible O(2)H, O(3)H, and O(6)H in the cellulose of developing cotton fibers were measured by conducting a reaction to a low degree of substitution under mild conditions in an aqueous medium. Raw cotton fibers from unopened bolls and from mature, opened bolls were studied. Correction was made for the presence of a β‐1,3‐glucan that was detected by substitution at the abundant O(4)H of this polysaccharide. The order of decreasing availability of hydroxyl groups of cellulose was O(2)H > O(6)H > > O(3)H. Results indicate that cellulose in the secondary wall of the cotton fiber is laid down with a high degree of order and that this order decreases with opening of the boll.
Preparation of a polymeric membrane with lipoamide structure and its application to electron transport across membrane
Authors: Nambu Yoko , Endo Takeshi , Okawara Makoto
Published: April 2003

A lipoamide (LAm) structure was introduced into a polymeric membrane by chemical modification of poly(γ‐methyl‐D‐glutamate) (PMG). A. redox reaction proceeded across the membrane mediated by pendant LAm groups as solid carriers. It is suggested that the electron transport process in the membrane is derived from the exchange reaction between reduced LAm (thiol) and LAm (disulfide).
Synthesis of polymeric crown ethers and thermoregulated ion complexation effects
Authors: Kahana N. , Deshe A. , Warshawsky A.
Published: April 2003

The alkylation of catechol with (chloromethyl)styrene–divinylbenzene copolymer 1 produces the polymer‐bound catechol 2, which upon reaction with a series of polyglycol dihalides affords macrocyclic polymeric benzo crown ethers 3, in fair yields. The alkylation of polybenzylamine 4 with polyglycol dihalides leads to diazapolymeric pseudocrown ethers 5. The degree of conversion of the catechol groups into macrocyclic ether groups and the residual concentration of diol groups were estimated from elemental analysis, weight‐gain data, and the analysis of bis‐2,4‐dinitrophenyl derivatives of the residual diol groups. The ion‐coordination patterns for the polymeric crowns were determined using distribution and column techniques. Equilibrium distribution values in methanol in the temperature range 20–60°C, for the perchlorate, thiocyanate, or bromide salts, have led to the following conclusions: (1) The spheric recognition patterns, typical of crown ethers in solution, are fully reproduced in the polymeric analogs. (2) The order of binding constants is K > Cs > Na > Li for polymeric benzocrown‐6 (3Hc) and benzocrown‐8 (3Hd) and K > Cs ≅ Na > Li for polymeric benzocrown‐4 (3Ha) and benzocrown‐5 (3Hb). (3) The polymers bind alkali metal cations by two mechanisms: the residual diol groups by ion exchange mechanism, and the crown groups by a salt‐coordination mechanism; the second mechanism is temperature‐dependent. Consequently, a thermal increase of 40°C causes a spontaneous elution, by “thermal shock,” and a three‐fold increase in the eluent of the original ion concentration. (4) Quantitative release of all the bound salt is observed.
Polymeric catalysis: Imidazoles grafted onto poly(vinylamine). I. Synthesis and grafting of imidazolylalkanoic acids
Authors: Tomko Richard , Overberger C. G.
Published: April 2003

Some ω‐(1‐imidazolyl) and ω‐[4(5)‐imidazolyl]alkanoic acids were synthesized and grafted onto poly(vinylamine) with an amide bond. These water‐soluble grafts were used to study the kinetics of the esterolysis of activated phenyl esters. The 1‐substituted imidazoles were prepared by the reaction of the sodium salt of imidazole with the ethyl ω‐bromoalkanoates. The 4(5)‐substituted imidazoles were prepared from urocanic acid or 4(5)‐hydroxymethylimidazole. The ω‐(1‐imidazolyl)alkanoic acids were grafted onto poly(vinylamine) via their acyl–guanidine derivatives; the 3‐[4(5)‐imidazolyl]propanoic acid was grafted with a water‐soluble carbodiimide.
Effects of potential on electroinitiated copolymerization of styrene and β‐bromostyrene
Authors: Toppare L. , Eren S. , Akbulut U.
Published: April 2003

Copolymerization of styrene and β‐bromostyrene, by constant potential electrolysis, in 1,2‐dichloroethane was achieved at various applied potentials. Effect of polymerization potential on the copolymer composition and the reactivity ratios was studied. Monomer reactivity ratios were determined by integrated Lewis–Mayo equation.
Multiphoton infrared laser‐induced degradation of polydimethylsiloxane and hexamethyldisiloxane
Authors: Manders W. F. , Bellama J. M.
Published: April 2003

The IR laser‐induced degradations of liquid polydimethylsiloxane (PDMS) vapor and of hexamethyldisiloxane vapor have been studied in order to determine whether the high temperature thermal properties of the dimethylsiloxane unit is best represented by SiO bond rearrangement (the conventional pyrolysis mechanism) or SiC bond cleavage (the thermodynamic reaction pathway). The volatile products of these pulsed laser experiments with various viscosities of PDMS are methane, ethane, ethylene, and hydrogen. These results are consistent with SiC bond cleavage to form methyl radicals, which can then recombine to form ethane or abstract a hydrogen atom from a matrix molecule to form methane. The presence of ethylene and hydrogen can be explained by the decomposition of hot ethane molecules. No evidence of SiO bond cleavage was observed. Reaction temperatures are estimated with computer modeling using heat capacity data.
Laser‐initiated polymerization of epoxies in the presence of maleic anhydride
Authors: Sadhir R. K. , Smith J. D. B. , Castle P. M.
Published: April 2003

Laser‐initiated polymerization of cyclohexene oxide in the presence of maleic anhydride was investigated. The influences of solvents laser irradiation time and the monomer feed ratio on the polymer yield and composition were evaluated. The rate of polymerization increased with an increase in the molar concentration of maleic anhydride in the monomer feed. Short irradiation times of 1–3 min duration gave very high yield of epoxy polymer (>80% conversion). Infrared spectral studies of the polymer product indicated the formation of polyether linkage at lower levels of conversion and an adduct of polyether and maleic anhydride at higher polymer conversions. The quantitative chemical analyses results also showed similar results. The results indicated that the polymerization was initiated by the excited charge transfer complex between the electron donor, cyclohexane oxide, and the electron acceptor–maleic anhydride. In the initial stages of polymerization, cyclohexene oxide undergoes a cationic polymerization in the presence of the radical anion of maleic anhydride. Laser‐initiated polymerization of cyclohexene oxide/maleic anhydride is several hundred times more efficient than UV‐initiated polymerization, as measured by the energy absorbed by the polymer system.
Block copolyurethanes based on polyoxytrimethylene glycols
Authors: Conjeevaram S. V. , Benson R. S. , Lyman D. J.
Published: April 2003

Trimethylene oxide was polymerized to polyoxytrimethylene glycol by two synthetic routes. High molecular weight polytrimethylene oxide was synthesized using a coordination catalyst system consisting of triethylaluminum, acetylacetone, and water, then ozonized and reduced with lithium aluminum hydride in anhydrous ether to form hydroxyl end‐capped polyoxytrimethylene glycol. In the second route, the polyoxytrimethylene glycols were synthesized directly by the cationic polymerization of trimethylene oxide with boron trifluoride/ethyl ether as catalyst and 1,4 butanediol as co‐initiator. (AB)n block copolyether–urethane–ureas based on these polyoxytrimethylene glycols were synthesized and characterized by differential scanning calorimetry, and dynamic mechanical and stress–strain measurements.
Synthesis and morphology of BAB type poly(styrene‐b‐2‐methyl‐2‐oxazoline) block copolymers
Authors: Ishizu Koji , Ishikawa Satoshi , Fukutomi Takashi
Published: April 2003

Well defined BAB‐type poly[styrene(ST)‐b‐2‐methyl‐2‐oxazoline(MeOz)] was prepared by the cationic polymerization of α,ω‐p‐toluenesulfonic acid ester‐terminated PST (PST‐BTs) as an initiator. Alkaline hydrolysis of this block copolymer was carried out under various reaction conditions to obtain BAB‐type poly[ST‐b‐ethylene imine(EI)]. Morphologies of these block copolymer specimens cast from several solvents were observed by electron microscope. The results are discussed in some detail.
Cation binding properties of poly(crown ethers) with photodimerizable groups
Authors: Shirai Masamitsu , Orikata Takao , Tanaka Makoto
Published: April 2003

Polymers that have crown ether groups as cation binding sites and cinnamic acid ester groups as photodimerizable groups were prepared by the cationic polymerizations of 2‐vinyloxyethyl 4′‐(2,3‐benzo‐1,4,7,10,13‐pentaoxa‐2‐cyclopentadecene)acrylate and 2‐vinyloxyethyl 4′‐(2,3‐benzo‐1,4,7,10,13,16‐hexaoxa‐2‐cyclooctadecene)acrylate. When irradiated with ultraviolet (UV) light the cinnamic acid ester groups of the polymers caused dimerization in dilute solution without the formation of insoluble materials. The irradiation was carried out in a dioxane solution and an aqueous solution in the presence and absence of salts. The effect of phototransformation of polymers on the cation binding properties was investigated by a method of picrate salts extraction. The binding ability of the phototransformed polymers for alkali and alkaline earth metal cations was higher than that of the native polymer. Furthermore the cation binding ability of the phototransformed polymers was less sensitive to temperature than that of the native polymer. The effect of the degree of photodimerization of the polymers and the concentration of KCl that exists during irradiation on the cation binding ability was also investigated.
Polymerization of 2‐azabicyclo[2,2,1]heptan‐3‐one and its copolymerization with 2‐pyrrolidone
Authors: Cho Hyun‐Nam , Choi Kil‐Yeong , Choi Sam‐Kwon
Published: April 2003

The anionic polymerization of a bridged bicyclic lactam, 2‐azabicyclo[2,2,1]heptan‐3‐one (ABHO), was carried out in bulk and in solution under various reaction conditions. In general bulk polymerization of ABHO was superior to solution polymerization in conversion and degree of polymerization. The resulting polymer exhibited good thermal stability at temperatures up to 300°C. The melting point and decomposition temperature of this polyamide, poly(cyclopentane‐1,3‐diyliminocarbonyl), were about 307 and 335°C, respectively. Copolymerization of ABHO with 2‐pyrrolidone was also made at 30°C and a varying weight percentage of ABHO with potassium pyrrolidonate as catalyst and CS2 as activator. Copolyamides that contained 15 w % of ABHO decomposed at a temperature higher than the melting point by almost 30°C. Thus the thermal stability of copolymers compared with that of nylon‐4, was greatly improved. Moisture sorptions of homopolymers and copolymers were always larger than those of other polyamides (nylon 4 and 6) at any relative humidity. Tenacity and elongation at the break of melt‐spun fibers obtained from copolyamides that contained 15 w % of ABHO without the drawing and annealing process were 1.25 g/den and 13.1%, respectively.
Magnesium chloride supported high mileage catalyst for olefin polymerization. VII. Determinations of concentrations of titanium–polymer and aluminum–polymer bonds
Authors: Chien James C. W. , Kuo Chi‐I
Published: April 2003

Two methods were used in an attempt to determine by radioquenching the active site concentration, [Ti*], in a MgCl2 supported high activity catalyst. For the reactions of tritium labelled methanol, the kinetic isotope effects were first determined: kH/kT = 1.63 for the total polymer and 1.67 for the isotactic polypropylene fraction. Polymerizations were quenched with an excess of isotopic CH3OH after various lengths of time, at different A/T (amount of AlEt3 with 0.33 equivalent of methyl‐p‐toluate to amount of Ti in the catalyst) ratios, and temperatures. From the known specific activity of tritium in CH3OH and radioassay of the polymer, value of the total metal polymer bond, [MPB], can be obtained. [MPB] increases linearly with polymerization time. Extrapolation to t = 0 gives [MPB]0, which should be close to [Ti*] because chain transfer with aluminum alkyls to produce Al–P bonds is negligible during very early stage of the polymerization. The values of [MPB]0 range from 7–30% of the total Ti; the number of MPB is nearly equally distributed in the amorphous and isotactic fractions of polypropylene in most runs. The rate of incorporation of radioactive CO into polymers produced by the MgCl2 supported high mileage catalyst is far slower than that claimed by some investigators for TiCl3 type catalysts. There is an initial rapid phase of incorporation of CO which lasts for about 1 hr of contact time. The subsequent rate of CO incorporation steadily declines, yet there is no constant maximum value of radioactivity even after 48 h of reaction in the absence of monomer. Radioquenching of polymerizations with CO was also performed at several temperatures and A/T ratios. In all cases, the maximum [Ti–P] was reached after 30–40 min of polymerization, whereas the maximum rates of polymerization, Rp,m, occurred within 3–10 min. In fact, the rate of polymerization decays to a small fraction of Rp,m after 30–40 min. Furthermore, this maximum value of [Ti–P] remains constant until the end of polymerization (t = 90 min). Therefore, isotopic CO is not reacting with the initially formed active sites Ti1*, but only with those sites, Ti2*, which predominate during the later stage of polymerization.
Synthesis of poly[S‐(2–9′‐acridinylethyl)‐L‐cysteine] and its TCNQ salt
Authors: Oshima Ryuichi , Sato Tadanori , Kumanotani Ju
Published: April 2003

Poly[S‐(2–9′‐acridinylethyl)‐L‐cysteine] (5) was synthesized by the N‐carboxy anhydride procedure. It was converted to the trifluoroacetic acid salt (6), which was treated with LiTCNQ in methanol to give the TCNQ anion radical salt (7). 7 showed electrical conductivity of 10−8 S/cm at 295 K.
Mechanochemical reactions of elastomers with metals
Authors: Gent A. N. , Rodgers W. R.
Published: April 2003

Metal powders were incorporated into various elastomers and the mixtures were subjected to intense shearing in air or a nitrogen atmosphere. The molecular weight after shearing was still relatively high, however; greater than 100 kg/mol. The elastomer was then dissolved and centrifuged to remove the metal particles and the solution was analyzed for reaction products. A strongly ultraviolet (UV)‐absorbing species was formed by shearing a styrene–butadiene copolymer (SBR) with iron powder. The concentration increased with the concentration of iron powder in the mixture and the extent of shearing, and it was greater after shearing in a nitrogen atmosphere. These results are attributed to the direct reaction of macromolecular radicals, formed by shearing, with iron powder to yield an iron–polymer compound. Natural rubber (cis‐polyisoprene), which absorbed 100–200 μg of iron per gram of polymer, was about as reactive as SBR. Polybutadiene was less reactive, and an ethylene–propylene copolymer did not react with or solubilize a significant amount of iron. Zinc was, in general, solubilized to a somewhat lesser degree than iron, whereas aluminum powder appeared to undergo virtually no reaction with sheared elastomers. The maximum extent of reaction (solubilization) was of the order of one metal atom per final polymer molecule, which was consistent with the proposed mechanism. Moreover, an analogous reaction took place between simple organic radicals and iron particles in suspension.
Synthesis of poly(vinyl alcohol) containing asymmetric nucleic acid base derivatives as grafted pendants
Authors: Overberger C. G. , Lu Chengxun
Published: April 2003

The preparations of new model polymers of polynucleotides with linear poly(vinyl alcohol) (PVA) backbones and an optically active nucleic acid base derivative as a pending side chain are described. (±)‐, (+)‐, and (−)‐2‐(thymin‐1‐yl)propionic acid were grafted onto PVA through ester bonds by direct coupling with dicyclohexylcarbodiimide (DCC) in the presence of highly active catalyst 4‐pyrrolidinopyridine (PPY) to give optically active graft polymers. The corresponding monomer and dimer models have been prepared.
Polychloroprene. II. Etude comparée de la microstrusture par RMN 1H et 13C. Thermodynamique de propagation des différentes unités structurales
Authors: Petiaud Roger , Pham Quang Tho
Published: April 2003

A microstructure analysis of polychloroprenes by 1H and 13C NMR produced slightly different results which, however, are in good agreement. The main uncertainty concerned the assignment of the 1,4‐cis and trans head‐to‐head and tail‐to‐tail additions. In the (+ 12, +70°C) region of polymerization temperatures the principal addition mode was 1,4. An increase in the polymerization temperature to 70°C increased the abnormal head‐to‐head, tail‐to‐tail additions, and 1,4‐cis additions (6–7%), and all vinyl structures that were not higher than 2–3% were equally distributed between 1,2 and 3,4. Under the experimental conditions used in this study no isomerized vinyl structures were found. As in all radical polymerizations the influence of temperature on the propagation mechanisms, namely, the addition modes, was relatively weak, but because of the great number of possible addition modes in microstructure—physicomechanical relationships variations in the microstructure must be taken into account. Only 1H and 13C NMR are capable of determining these variations quantitatively.
Benzophenone‐sensitized photopolymerization of methyl methacrylate using dimethyl aniline–maleic acid combination as photoinitiator
Authors: Ghosh Premamoy , Chowdhury Dilip Kumar
Published: April 2003

Benzophenone (BP)‐sensitized photopolymerization of methyl methacrylate (MMA) in near UV/visible light was studied at 40°C using dimethylaniline maleic acid (DMA—MA) combination as the photoinitiator. An instantaneous 1:1 complexation between DMA and MA takes place when they are mixed together in acetonitrile. Also, instantaneous complex formation occurs between DMA and MMA and between MA and MMA when they are dissolved in MMA in low concentrations, separately. Interestingly, when equimolar proportions of DMA and MA are mixed together in MMA, there is indication for further instantaneous complexation between (DMA—MMA) complex and (MA—MMA) complex forming the actual initiating species in the photopolymerization system. Initiator exponent was 0.28 and monomer exponent varied between 0.0 to 1.8 depending on the nature of the solvent and range of dilution used. Analysis of kinetic data indicates a free radical mechanism for the polymerization with initiator‐dependent termination. Chain termination via degradative initiator transfer is quite significant; but the degradative effect becomes much less prominent in the higher range of initiator concentration indicating that the reinitiation reaction following the initiator transfer process assumes more proportionate significance as the initiator concentration is increased, probably as a result of higher reinitiation efficiency. Polymers obtained gave evidence for the incorporation of aromatic (amine) end groups in them.
Friedel–Crafts polymerization of fluorene with methylene chloride, methoxyacetyl chloride, and chloromethyl methyl ether
Authors: Nystuen Natalie J. , Jones Martin B.
Published: April 2003

The polymerization of fluorene with various chloromethylating reagents (methylene chloride, methoxyacetyl chloride, and chloromethyl methyl ether) in the presence of aluminum chloride was studied. The products that were obtained were insoluble, infusible, colored powders which contain a low concentration of aromatic radicals. Each of the polymers is composed predominantly of fluorene nuclei bridged at the 2 and 7 positions by methylene groups. In addition, the materials possess varying amounts of crosslinked and ring‐fused moieties. Based on physical and spectral properties and reaction stoichiometry, the fluorene/methylene chloride polymer is the most highly crosslinked of the three. The fluorene/methoxyacetyl chloride and fluorene/chloromethyl methyl ether polymers are similar to each other in most respects.
Photostabilizing activity of tertiary hindered amines
Authors: Kurumada Tomoyuki , Ohsawa Hisayu , Oda Osamo , Fujita Takashi , Toda Toshimasa , Yoshioka Takao
Published: April 2003

The influence of the N‐alkyl group of tertiary hindered amines on the photostabilization of polymers was studied. The photostabilizing effects of the tertiary amine derivatives of 4‐benzoyloxy‐2,2,6,6‐tetramethylpiperidine (1a) in polypropylene were compared. All tertiary amine derivatives having α‐H to hindered N showed higher effectiveness than 1a. Model liquid phase photoxidations were carried out by irradiating (UV‐lamp) the solutions of tertiary hindered amines containing tert‐butyl hydroperoxide as a photoinitiator. The tertiary hindered amines were oxidized more easily than corresponding parent hindered amine and converted to the parent amine, which was identified as its salt, resulting from the carboxylic acid produced from the N‐alkyl group by oxidation. The thermal reaction of the tertiary hindered amines with tert‐butyl hydroperoxide was also studied in the liquid phase. The tertiary hindered amines decomposed tert‐butyl hydroperoxide more rapidly than the parent secondary hindered amine, and generated the parent amine. It was also found that the photostabilizing effects of tertiary hindered amines for polyolefins were higher than that of the parent secondary hindered amine.
Chemical release control: Sulfonate esters from perfume and herbicide alcohols and p‐styrenesulfonyl chloride
Authors: Kamogawa Hiroyoshi , Haramoto Yuichiro , Misaka Yukihiro , Asada Yasuhiro , Ohno Yumiko , Nanasawa Masato
Published: April 2003

p‐Styrenesulfonate esters of primary and secondary perfume alcohols and phenols, including citronellol, 1‐menthol, borneol, β‐phenethyl alcohol, eugenol, p‐anisyl alcohol, cinnamyl alcohol, and geraniol, and herbicide alcohols such as 2,4‐dichloro‐ and 2,4,5‐trichlorophenoxy‐ethanols were synthesized using p‐styrenesulfonyl chloride in the presence of bases such as pyridine, triethylamine, sodium hydrogen carbonate, and sodium hydride. The hydrolytic behavior of sulfonate ester monomers and their copolymers with N‐vinyl‐2‐pyrrolidone to liberate perfume and herbicide alcohols was structure‐dependent, thereby affording chemical release control.
Thermal behavior of holo‐ and hemicellulose obtained from rice straw and bagasse
Authors: Sefain Magdi Z. , El‐Kalyoubi Samira F. , Shukry Nadia
Published: April 2003

Thermal gravimetric analysis, and differential thermal behavior of holo‐ and hemicelluloses obtained from rice straw and bagasse were investigated. Degradation was found to be of first order reaction. The activation energy values and the rate constants were calculated from the kinetic of weight loss. Hemicellulose was found to be less stable than holocellulose, and the stability of the samples was arranged in the order, rice straw holo‐ > bagasse holo‐ > rice straw hemi‐ > bagasse hemicellulose. Degradation of rice straw (holo‐ as well as hemicellulose) was performed via two exothermic processes, whereas bagasse hemicellulose combustion was completed through three exothermic processes. The magnitude and the shape of the exotherms depend, mainly, on the chemical composition of the sample.
Preparation and characterization of poly(copper 2,3,9,10,16,17,23,24‐octacyanophthalocyanine)
Authors: Lin John W‐P. , Dudek Les P.
Published: April 2003

Dark blue poly(copper 2,3,9,10,16,17,23,24‐octacyanophthalocyanine) has been prepared by reacting 1,2,4,5‐tetracyanobenzene with cuprous chloride in 1‐methyl‐2‐pyrrolidone at ca. 150°C. The product has been characterized by elemental analysis, thermal analysis, infrared and UV‐VIS spectroscopies. The polymer has high purity and exhibits good thermal stability in an inert atmosphere.
An ESCA investigation of the inductively coupled RF plasma polymerization of fluoronaphthalene and fluoronaphthalene/hydrogen mixtures
Authors: Munro H. S. , Till C.
Published: April 2003

1‐Fluoronaphthalene was plasma polymerized and its composition and structure, as a function of position, power, and temperature, were examined by ESCA. The F:C ratio of the deposited film was lower than that of the starting monomer both at room temperature and at 150°C. An asymmetry of the main C1s photoionization peak was noted. Plasmas were also excited in fluoronaphthalene/hydrogen mixtures where extensive fluorine elimination and hydrogen incorporation occurred. This gave direct evidence that the height of step function or asymmetry of the main C1s peak is related to the degree of saturation in the compound.
Polyetherimides. I. Preparation of dianhydrides containing aromatic ether groups
Authors: Takekoshi T. , Kochanowski J. E. , Manello J. S. , Webber M. J.
Published: April 2003

A general synthetic method and characterization of bis(ether anhydride)s, the ether containing aromatic dianhydrides of the following structure, are presented.
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The method involves aromatic nitro‐displacement of N‐substituted 3‐ or 4‐nitrophthalimide with bisphenoxides to form N‐substituted arylene‐bis(phthalimido)ethers or bis(ether imide)s. Sixteen structurally different bis(ether imide)s have been prepared and subsequently converted to the corresponding bis(ether anhydride)s. Bis(ether anhydride)s are stable crystalline compounds of a moderate reactivity. Unlike highly reactive dianydrides such as pyromellitic and benzophenonetetracarboxylic dianhydrides bis(ether anhydride)s are semipermanently stable against hydrolysis in the presence of atmospheric moisture.
Modelling the microstructure of emulsion copolymers
Authors: Forcada J. , Asúa J. M.
Published: April 2003

A simple model for predicting the microstructure of emulsion copolymers is presented. The model, which is based on the Markov processes, allows the prediction of the copolymer sequence distribution as accurately as the previous complex model.
Conversion of solid poly(methyl vinyl ether‐alt‐maleimide) to poly(methyl vinyl ether‐alt‐maleic anhydride)
Authors: Field Nathan D. , Li Chi
Published: April 2003

Solid poly(methyl vinyl‐alt‐maleimide), when subjected to heating at 100°C while being vacuum pumped at 0.1 mm Hg pressure, was converted to a copolymer in which a substantial portion of the imide groups were converted to anhydride groups. Similarly, heating at 100°C at atmospheric pressure in a circulating air oven brought about the same reaction but at a faster rate. This confirms the hypothesis that the formation of maleic anhydride comonomer units from poly(methyl vinyl ether‐alt‐ammonium maleamate) not only proceeds directly by ring closure of amic acid formed by loss of ammonia but probably also includes, as a parallel pathway, hydrolysis by atmospheric moisture of maleimide comonomer units.
Polyhalogenated polyamides IV. Synthesis and characterization of polyhalogenated polyamides in a melt–solid process at high temperature and in solution at low temperature
Authors: Díz F. R. , Tagle L. H. , Padilla M. E.
Published: April 2003

A new series of polyhalogenated, principally polybrominated polyamides have been prepared either by polymerization in a melt‐phase process at high temperature or by a low‐temperature solution process. The polymers were obtained from perchloroterephthaloyl‐, perbromoterephthaloyl‐, and 2,5‐dibrometerephthaloyl dichlorides and tetrabromophthalic anhydride with aromatic and aliphatic diamines. They were characterized by elemental analysis, infrared spectroscopy, intrinsic viscosities, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and flame‐resistance testing.
Copolymerization of vinyl ketones with allylbenzene in the presence of zinc chloride
Authors: Masuda Seizo , Omochi Teruyuki , Ota Tadatoshi
Published: April 2003

Copolymerization of 3‐buten‐2‐one (MVK) and 3‐methyl‐3‐buten‐2‐one (MIPK) with allylbenzene (AB) in the presence of zinc chloride (ZnCl2) was studied. The apparent monomer reactivity ratio decreased with an increasing concentration of ZnCl2 added. By assuming a terpolymerization system as free vinyl ketone (M1), vinyl ketone complexed with ZnCl2 (M2), and AB(M3), the absolute monomer reactivity ratios were determined by using the least squares method: k11/k12 = 0.0038, k11/k13 = 11.77, k22/k21 = 1.37, and k22/k23 = 3.77 for the MVK‐AB system, and k11/k12 = 0.0070, k11/k13 = 55.47, k22/k21 = 1.84, and k22/k23 = 11.16 for the MIPK‐AB system, respectively. It is seen from these values that the complexed vinyl ketones are more reactive to both polymer radicals which have free and complexed vinyl ketone units at its terminal position than the free vinyl ketones. Q and e values for MVK and MIPK complexed with ZnCl2 were found to be Q = 850, e(MVK)2ZnCl2 = 2.97, Q = 2.62, respectively.
The effect of temperature and solvent on the synthesis and properties of nylon 610 made from sebacyl bisketene
Authors: Garner David P. , Fasulo Paula D.
Published: April 2003

Polyamides were synthesized at −60°, −40°, −20°, and 0°C from sebacyl bisketene and 1,6‐hexamethylenediamine in either acetone or methylene chloride. At the lower reaction temperatures oligomers predominated in solution but at 0°C the product was crosslinked. The polyamides were subjected to m‐cresol extraction at elevated temperatures for up to 14 days. The m‐cresol soluble and insoluble fractions were characterized by weight, infrared spectroscopy, dilute solution viscosity, and gel permeation chromatography. Infrared analysis of the soluble and insoluble portions showed the degree of branching of the polyamide, identified the branching point at the secondary amide proton position, and gave an indication of the degree of branching required before insoluble products resulted. Dilute solution viscosity and gel permeation chromatography were used to demonstrate the existence of low molecular weight (Mw) oligomer species in the soluble portion. Differential scanning calorimetry experiments revealed that polyamides synthesized below their glass transition temperature would not crystallize which resulted in abnormal thermal characteristics. Annealing at elevated temperatures allowed crystallization to occur and the expected thermal character to develop.
Polymerization of water‐in‐oil microemulsions: Methyl methacrylate, acrylic acid, and sodium acrylamidostearate
Authors: Chew C. H. , Gan L. M.
Published: April 2003

Water‐in‐oil (w/o) microemulsions of methyl methacrylate (MMA), acrylic acid (AA), sodium acrylamidostearate (NaAAS), and water were investigated. MMA, AA, and NaAAS could be terpolymerized in these microemulsions. For a composition of 54% MMA, 34% AA, 2% NaAAS, and 10% H2O, polymers of high molecular weights of about 1,000,000 were obtained between 3.5 to 24% polymer conversion. The system became a transparent gel when conversion exceeded 36%. Transparent solid terpolymer containing water up to 16% were also obtained after fully polymerizations of certain compositions.
Further investigations into the formation of imide linkages during the amidation of mono‐ and difunctional aroxyacetyl chlorides
Authors: Clark A. J. A. , Lenk R. S.
Published: April 2003

This paper further investigates imide formation in amidation reactions involving Bischloride A2 and suitably selected mono‐ and difunctional analogues on the one hand, and primary aromatic mono‐ and diamines on the other. It also investigates the reaction of these acid chlorides with secondary mono‐ and diamines. If, say, N,N′ dimethyl p‐phenylene diamine and hydroquinone dioxyacetyl chloride or bischloride A2 were to react quantitatively, then a linear unbranched polyamide would be expected to be the result which, in the absence of any hydrogen remaining at the amide link, would no longer present a site for further electrophilic attack on the part of the exceptionally reactive aroxyacetyl chloride. There also arises the possibility that a monoamine such as aniline could conceivably act as a difunctional reagent in the presence of aroxyacetyl chlorides. In the event of this reaction proceeding quantitatively one would expect to obtain a linear polyimide in which each imide–nitrogen atom carries a phenyl group. In carrying out the experimental preparative work which is required to elucidate these points we used both monofunctional reactants as model compounds and difunctional reactants in order to assess the polymeric resultants. The products were characterized by means of 1H‐NMR, 13C‐NMR, IR spectroscopy, TLC, and Tg determinations. The conclusions drawn on the basis of the experimental work provided a satisfactory interpretation of the complex reactions which occur during the polyamidation of bischloride A2. They also point to interesting possibilities for the use of difunctional aroxyacetyl chlorides as modifying comonomers in minor amounts in the preparation of copolyaramides with reduced crystallinity. Such copolyaramides would be expected to have better solubility in common solvents and to be more easily processable than the rather specialized and extremely high‐melting polyaramides currently commercially available and could therefore extend the range of useful applications for this class of polymers.

The experimental section is preceded by an introduction which briefly reviews the “state of the art,” especially as far as bischloride A2‐based polyamidation reactions are concerned. It is followed by a discussion of the results, by the conclusions, and a brief summary.
Photocrosslinking of poly(2,3‐epithiopropyl methacrylate) by the oxidation of pendant episulfide groups
Authors: Tsunooka Masahiro , Tanaka Shingo , Tanaka Makoto , Egawa Hiroaki , Nonaka Takamasa
Published: April 2003

In the photocrosslinking of poly(2,3‐epithiopropyl methacrylate) (PETMA) films the effect of the pendant episulfide group's oxidation on the crosslinking of PETMA was investigated. Thermal crosslinking of PETMA is promoted by peroxides such as benzoyl peroxide and hydrogen peroxide. IR spectrum of the crosslinked PETMA showed that the reaction proceeded through the oxidation of episulfide groups by the peroxides. The anthracene (An) sensitized photocrosslinking of PETMA films also proceeded via the oxidation of episulfide groups by singlet oxygen. It was found that residual tetrahydrofuran (THF) in the films remarkably increased the rate of the photocrosslinking and/or reduced the induction period. From the further investigation concerning casting solvents it was found that residual CS2, CCl4, and CHCl3 in films increased the rate of the photocrosslinking and/or reduced the induction period of the photocrosslinking. The disappearance rate of An in the films was also increased by the presence of residual CS2, CCl4, and CHCl3, differring from the result of THF. These results were explained by a difference in lifetime of singlet oxygen in the films. From the results were explained by a difference in lifetime of singlet oxygen in the films. From the results concerning the effects of hydroperoxides such as THF hydroperoxide and t‐butyl hydroperoxide on the photocrosslinking of PETMA films the acceleration effect of the residual THF was deduced to be due to the promotion of singlet oxygen‐oxidation of sulfide groups by protic compounds such as THF hydroperoxide and H2O in the THF.