bluuebunny/crossref_metadata_2025 huggingface dataset:
Polymerization of cyclohexene oxide with aluminum complex‐silanol catalyst. IV. Photopolymerization with Ph3SiCOPh‐Al complex‐alcohol catalyst system
Authors: Hayase S. , Ito T. , Suzuki S. , Wada M.
Published: April 2003

A new catalyst system (Ph3SiCOPh‐aluminum complex‐alcohol) was investigated for photopolymerization of cyclohexene oxide. Polymer conversion and molecular weight increased with polymerization time. When a Ph3SiCOPh‐Al (n‐Praa)3‐alcohol catalyst system was used the catalyst activity decreased, depending on the alcohol: i‐PrOH > n‐PrOH > i‐BuOH > MeOH > t‐BuOH > H2O. When the Ph3SiCOPh‐Al complex‐i‐PrOH catalyst system was used the catalyst activity decreased, depending on the ligand of the Al complex: ß‐ketoester > orthocarbonyl phenol > ß‐diketone. Benzophenone derivatives were effective for catalyst activation as a photosensitizer.
Functionalization of polystyrene. III. Synthesis of polymeric thiol reagents
Authors: Stern Meir , Fridkin Mati , Warshawsky Abraham
Published: April 2003

The synthesis of polymer‐bound thiol reagents, supported on macroporous 4% divinylbenzene co‐polymer (Amberlite XE‐305), via three synthetic approaches is described: (i) Alkylation or acylation of XE‐305 with 3‐nitro‐4‐halogen‐substituted benzyl chloride or benzoyl halide yielding 3‐nitro‐4‐halobenzene‐bound species, followed by substitution of the activated polymeric halogen atom with sulfur (see Scheme 1). (ii) Formation of a thiol ether by a direct substitution of an active polymeric halogen by reaction with benzylthiol, followed by chlorination, thiolation, and reduction (see Scheme 2). (iii) Attachment of a prepared tailor‐made disulfide to aminomethyl function of a polymeric support, followed by reduction (see Scheme 3). The polymers were tested for their free‐thiol content by 5, 5′‐dithiobis(2‐nitrobenzoic acid) (Ellman's reagent12) in DMF. Their thiolytic activity was investigated in the removal of 2‐nitrophenylsulphenyl (Nps) group from Nps‐protected amino acid (Scheme 4). Site‐site interaction between the polymer‐bound thiol with its activated halide precursor to yield polymeric sulfide during displacement reaction, and the interconversion of the polymeric thiols into polymeric disulfides at equilibrium or during reaction with Nps‐amino acids, observed, and is attributed to the flexibility of the polymeric matrices.
Copolymerization of glycidyl methacrylate with alkyl acrylate monomers
Authors: Dhal Pradeep K. , Ramakrishna M. S. , Babu G. N.
Published: April 2003

A newer approach to obtaining acrylic thermoset polymers with adequate hydrophilicity required for various specific end uses is reported. Glycidyl methacrylate (GMA) was copolymerized with n‐butyl acrylate (n‐BA), isobutyl acrylate (i‐BA), and 2‐ethylhexyl acrylate (2‐EHA) in bulk at 60°C. with benzoyl peroxide as free radical initiator. The copolymer composition was determined from the estimation of epoxy group. Reactivity ratios were calculated by the Yezrielev, Brokhina, and Roskin method. For copolymerization of GMA (M1) with n‐BA (M2) the reactivity ratios were r1 = 2.15 ± 0.14, r2 = 0.12 ± 0.03; with i‐BA (M2) they were r1 = 1.27 ± 0.06, r2 = 0.33 ± 0.031; and with 2‐EHA (M2) they were r1 = 2.32 ± 0.14, r2 = 0.13 ± 0.009. The reactivity ratios were the measure of distribution of monomer units in a copolymer chain; the values obtained are compared and discussed.
Template effects in chelating polymers
Authors: Gupta S. N. , Neckers D. C.
Published: April 2003

Poly(4′‐methyl‐4‐vinyl‐2,2′‐bipyridine) has been prepared as have various copolymers with divinylbenzene. When polymerization is carried out in the presence of metal ions (Ni2+, Co2+, Cu2+) a metal‐containing copolymer is obtained which, when the metal ion is removed with acid, retains some memory of the original chelating metal.
Liposomes from α,ω‐dipolar amphiphiles with a polymerizable diyne moiety in the hydrophobic chain
Authors: Bader H. , Ringsdorf H.
Published: April 2003

Symmetric polymerizable α,ω‐dipolar C22‐diacetylenes were prepared by oxidative coupling of 10‐undecynoic acid and 10‐undecynol, respectively, by means of copper II salts in ethanolic solution. 10,12‐Docosadiyne‐1,22‐diphosphate (3)—by reaction of 10,12‐docosadiyne‐1,22‐diol (2) with POCl3—was polymerized in aqueous solution using UV irradiation to form deep blue, thermochromic solutions. By consonication of 3 with cholesterol, monolayer vesicles were formed. This was proven by encapsulation of 6‐carboxyfluorescein. These monomeric vesicles were polymerized by UV light to yield stable, deep blue polymeric vesicle suspensions.
Complexes of polyacids with poly(vinylbenzocrown ether)s and polyvinylbenzoglymes in water
Authors: Jaycox Gary D. , Sinta Roger , Smid Johannes
Published: April 2003

Insoluble complexes are formed in acidic aqueous media when poly(acrylic acid) (PAA) and poly‐(vinylbenzo‐18‐crown‐6) (P18C6) or polyvinylbenzoglymes are mixed. Complex formation results from hydrogen bonding between carboxyl groups and crown ether‐ or glyme–oxygen atoms as well as from hydrophobic interactions. The precipitation is pH dependent and was determined as a function of the ratio PAA to P18C6 or to polyglyme at different HCl concentrations in 10−4M solutions of polycrown or polyglyme. Precipitation is nearly quantitative in 0.01N HCl. The compositions of PAA/P18C6 precipitates were determined as a function of the initial PAA/P18C6 ratio in solution. The complexes with P18C6 can be solubilized in acidic media when crown‐complexable cations (K+, Cs+, Ba2+) are added, but the charged P18C6 reprecipitates in basic solution as a polysalt complex with the PAA–polyanion. More stable PAA–P18C6 complexes in the form of fibers can be obtained by interfacial complex formation. Poly(methacrylic acid) is less effective as a complex former.
Modification of PET with sterically hindered diols
Authors: Prasadarao M. , Pearce Eli M.
Published: April 2003

Poly(ethylene terephthalate) was modified by incorporating bis(hydroxyethyl) tetrasubstituted terephthalates (methyl, chlorine, and bromine) as a third component in the mole ratios of 2–50% (based on dimethyl terephthalate) which resulted in random copolyesters. The presence of steric hindrance imparted additional chain rigidity to the copolymer structure, as shown by increased glass transition temperature (Tg). The effectiveness of the steric groups for conferring rigidity to the copolymer structure was CH3 > Cl≃Br. The copolyesters which contained halogen substituents showed substantial enhancement in flame retardency compared with PET.
Solid‐state polymerization of acrylamide and its derivatives complexed with some lewis acids. II. Radiation‐induced in‐source polymerization
Authors: Żurakowska‐Orszagh J. , Mirowski K. , Chajewski A.
Published: April 2003

Radiation‐induced solid‐state polymerizations of complexes of N‐tert‐butylacrylamide, N‐tert‐amylacrylamide, and N‐tert‐hexylacrylamide with zinc chloride and zinc bromide have been studied. An accelerating effect of temperature and an inhibiting effect of oxygen on the polymerization process were observed. The activation energies have been established. The influence of monomer structure as well as the halide used on the polymerization rate have been discussed and some regularities have been pointed out. The polymers obtained show good solubilities in common solvents, which proves that they are not crosslinked.
Phthalocyanine polymers. II. Synthesis and characterization of some metal phthalocyanine sheet oligomers
Authors: Achar B. N. , Fohlen G. M. , Parker J. A.
Published: April 2003

Metal phthalocyanine oligomers that possess peripheral carboxylic acid groups were prepared by the reaction of pyromellitic dianhydride, a metal salt, urea, and a catalyst. These materials have blue to purple colors with a metallic luster and are soluble in sulfuric acid, dimethylsulfoxide, dimethylformamide, and dimethylacetamide. Their thermal stability is high in an anaerobic atmosphere with char yields of 80–85% at 800°C. Elemental, spectral, and titrimetric analyses and thermal studies were carried out to characterize them.
Unusual swelling behavior of films of polyvinyl‐ and polyvinylidene/fluorides in various solvents
Authors: Chapiro A. , Mankowski Z. , Schmitt N.
Published: April 2003

The swelling of PVF and PVDF films in various solvents was investigated. It was found that in the swollen state both polymers show little tendency to retain the solvent that leaks out under a mild pressure and evaporates quickly when the specimen is exposed to air. The equilibrium swelling ratios were measured in numerous solvents. From the results it is concluded that the solubility parameters are δPVDF = 12.0–12.3, δPVF = 12.0–12.1. The unusual swelling behavior is explained by strong polymer–polymer interactions via dipoles which tend to replace polymer–solvent interactions once the sample is withdrawn from the solvent.
Polymerization of phenylacetylene by triethyl aluminum and titanium tetraethoxide
Authors: Chiang Albert C. , Waters Paul F. , Aldridge Mary H.
Published: April 2003

The polymerization of phenylacetylene to polyphenylacetylene was accomplished with the combined catalysts triethyl aluminum and titanium tetraethoxide. The progress of the reaction was monitored by gas chromatography. The parameters included temperature (−80, 25, 140°C), solvent (benzene, chlorobenzene, toluene, cyclohexane, and nitrobenzene), mole ratio of catalysts (Al/Ti; 1.5, 3.0, 4.5, 6.0, and 9.0), aging times of catalysts (2, 10, and 40 min), and order of addition of reagents. Derivatives of polyphenylacetylene were obtained by the acylation of polyphenylacetylene with p‐nitrobenzoyl chloride, the sulfonation of polyphenylacetylene with benzenesulfonyl chloride, and the formation of polyphenylacetylene complexes with complexing agents such as bromine, iodine, iodine chloride, boron trifluoride, and ferric chloride. A new phenylacetylene‐acetylene product mixture was produced by the polymerization of phenylacetylene and acetylene at 25 and −80°C. The electrical conductivity of polyphenylacetylene and its derivatives is in the range of 10−10−10−3 Ω−1 cm−1.
Kinetics of polyesterification. II. Foreign acid‐catalyzed dibasic acid and glycol systems
Authors: Chen Show‐an , Wu K.‐ C.
Published: April 2003

Polyesterification of diacid and diol in the presence of the foreign acid p‐toluene sulfonic acid as catalyst was carried out under constant reaction temperatures of 140–166°C (rather than at the usual constant oil‐bath temperature) and at molar ratios r of diol to diacid of 1.2–3.5. The experimental data obtained do not fit conventional rate equations as they appear in the literature. On the basis of ion pair formation, consideration of proton transfer from acid to alcohol, variation in dielectric constant of the reaction mixture as conversion increases, and inclusion of reverse reaction due to presence of unremoved water, we proposed a reaction mechanism and rate equations. The rate equation fitted our experimental data quite well. In addition the self‐catalysis (absence of foreign acid) also showed promise, as confirmed by the experimental data measured under constant reaction temperatures, which appear in Part I.
Effect of pressure on the crystallization of poly(ethylene terephthalate)
Authors: Ihm Dae Woo , Cuculo John A.
Published: April 2003

The effect of pressure on the crystallization of poly(ethylene terephthalate) (PET) was studied. The Instron capillary rheometer was adapted as a high‐pressure/high‐temperature dilatometer to carry on experiments up to 40,000 psi. Isothermal measurements of PET melt density were made with a precision of ±0.5%. Analysis of the kinetics of crystallization of PET melt at high pressures reaffirmed the existence of low Avrami exponents and their noninteger values. To rationalize the crystallization mechanism with the observed low exponents it is proposed that an appropriate increase in pressure would effectively reduce the free volume of a crystallizable substance to a point at which an alteration of the crystallization mechanism or nucleation mode could occur. It is further shown that PET clearly exhibits two different and sharply defined stages of crystallization behavior at pressures above 10,000 psi. Based on the Avrami equation, the fraction of uncrystallized polymer for the initial stage is defined as an empirically determined function of time and pressure. There is good agreement between the predicted and experimental values over the pressure range investigated.
Laser‐initiated polymerization of charge‐transfer monomer systems
Authors: Williamson M. A. , Smith J. D. B. , Castle P. M. , Kauffman R. N.
Published: April 2003

The laser‐initiated polymerization of charge‐transfer monomer complexes was investigated with a pulsed nitrogen laser and an argon laser. Several donor‐acceptor monomer charge‐transfer systems were screened for polymerization in different solvents. Polymerization by laser initiation was achieved in two of these systems; that is, 2‐vinylnaphthalene/fumaronitrile and 9‐vinylanthracene/fumaronitrile. The best polymer yields were obtained with the 2‐vinylnaphthalene/fumaronitrile system in sulfolane solvent. The influences on the polymer yield and composition of solvents, varying focal path length, glass conditioning, initiation sources, environment, and monomer feed ratios were evaluated. Infrared (IR) spectral studies, gel permeation chromatography (GPC), and chemical analyses were performed to characterize the polymer products arising from the polymerization of 2‐vinylnaphthalene/fumaronitrile in sulfolane. The polymer contained a high percentage of sulfolane (ca. 1/3 mol fraction), presumably arising from solvent transfer to the growing polymer chains during the propagation phase of the polymerization.
Synthesis of corrosion‐inhibiting polythioesters
Authors: Truesdell J. W. , Van De Mark M. R.
Published: April 2003

Binary condensation copolymers of five monomers known to be corrosion inhibitors were synthesized by solution polymerization. The copolymers synthesized were poly(1,2‐ethanedithiol‐thiodiglycolate), poly(1,3‐propanedithiol‐3,3′‐thiodipropionate), poly(1,2‐ethanedithiol‐3,3′‐thiodipropionate), and poly(2,5‐dimercapto‐1,3,4‐thiadiazole‐3,3′‐thiodipropionate). Yields ranged from 77 to 89% and molecular weights from 10,100 to 24,300. Attempts to produce the condensation copolymers of thiodiglycolic acid chloride and 1,3‐propanedithiol or 2,5‐dimercapto‐1,3,4‐thiadiazole failed, yielding only telomeric products. The copolymers that were synthesized demonstrated significant corrosion‐inhibitory properties on steel samples in salt water.
Copolymerization of 3,4‐dimethyltetrahydrofuran with cyclic ethers
Authors: Malanga M. , Vogl O.
Published: April 2003

The copolymerization of 3,4‐dimethyltetrahydrofuran with selected cyclic ethers was studied. Although 3,4‐dimethyltetrahydrofuran did not homopolymerize, it readily copolymerized with propylene oxide and epichlorohydrin in an alternating fashion using the cationic initiator PF5. The reactivity ratios r1 and r2 for the copolymerization of 3, 4‐dimethyltetrahydrofuran and epichlorohydrin were r1 = 0.22 ± 0.05 and r2 = 0.11 ± 0.01, respectively.
Effect of stabilizers on the preparation of poly(ethylene terephthalate)
Authors: Chang Shuya , Sheu Ming‐Fa , Chang Nien‐Hsi
Published: April 2003

Previous investigators have indicated that stabilizers will block the transesterification catalyst in the preparation of PET by the DMT process. This was not the case when triphenyl phosphate (TPP) or Irganox 1010 was used as the stabilizer and manganous acetate as the catalyst. Stabilizers in this study included TPP, trimethyl phosphate (TMP), tetraethylammonium hydroxide (TEAOH), Irganox 1010, and Irganox 1222. Their effect on the properties of PET made by the TPA process was investigated. It was observed that TPP and TMP greatly reduced the carboxyl content of PET and that the others had little or no effect. All stabilizers lowered the diethylene glycol content of PET. The rate of polycondensation was slightly increased when a small amount of Irganox 1010, Irganox 1222, or TMP was added. Proper concentration of stabilizer should be chosen to obtain good stability and low diethylene glycol content. Among the five stabilizers studied TPP was the best with respect to carboxyl and diethylene glycol content and thermal stability. The concentration of TPP should be kept under 0.04% by weight of PET.
Mechanism of thermal degradation of polyurethane based on MDI and propoxylated trimethylol propane
Authors: Gaboriaud F. , Vantelon J. P.
Published: April 2003

The various pathways of degradation of polyurethane based on MDI and propoxylated trimethylol propane were studied from the analysis of degradation gases sampled at various temperatures during the heating rise. From the beginning of degradation (250°C) to 400°C, we suggest that the main mechanism is the fracture of the polyurethane molecule into primary amine, carbon dioxide, and propenyl ether, the last leading to propene. Beyond this temperature, the mechanism may be reduced to a depolymerization process followed by radical breakdown of the polyol chain and by stripping and rearrangement of simple radicals, all of these giving the gaseous species obtained.
High‐molecular‐weight poly(p‐phenyleneterephthalamide) by the direct polycondensation reaction with triphenyl phosphite
Authors: Higashi Fukuji , Ogata Shin‐Ichi , Aoki Yasuhiro
Published: April 2003

Poly(p‐phenyleneterephthalamide) of high molecular weight was obtained when the polycondensation of terephthalic acid and p‐phenylenediamine was carried out in N‐methylpyrrolidone (NMP) that contained dissolved CaCl2 and LiCl in the presence of pyridine. The molecular weight of the polymer obtained varied with the amount of pyridine relative to the metal salts and with the molar ratios of CaCl2 to LiCl, the maximum ηinh value of 4.5 being obtained under the conditions Py/(CaCl2 + LiCl) ≈ 2.5 (mol/mol), CaCl2/LiCl ≈ 1.2 (mol/mol), and LiCl + CaCl2 ≈ 4 g. Among the solvents tested, NMP was significantly effective for the reaction. Polycondensations of several combinations of other dicarboxylic acids and diamines were carried out with limited success.
Synthesis and characterization of polyethylenimine backbone polynucleotide models
Authors: Ludwick Adriane G. , Overberger C. G.
Published: April 2003

Nucleic acid analogs with a PEI backbone and uracil‐ and thymine‐containing pendants and their monomer and dimer models have been synthesized and characterized by means of 360‐MHz 1H‐NMR as well as 90‐ and 20‐MHz 13C‐NMR. 13C‐NMR was particularly useful in characterizing the primary structures of the polymers. While data from the monomer and dimer models can be assumed transferable to the polymers, some unique features of the 1H and 13C spectra of the polymers compared to the model compounds, give insight to the polymer structures.
Effects of diphenyliodonium hexafluorophosphate in the radiation‐induced cationic polymerization of styrene. Formation and decay processes of styrene dimer radical cation
Authors: Mah Soukil , Yamamoto Yukio , Hayashi Koichiro
Published: April 2003

The radiation‐induced cationic polymerization of styrene in methylene chloride is promoted by the addition of (C6H5)2IPF6, while the polymerization is inhibited in the presence of (C6H5)2ICl. The pulse radiolysis study reveals that both the yield and the lifetime of styrene dimer radical cation are increased by the addition of (C6H5)2IPF6, and, on the contrary, both are decreased in the presence of (C6H5)2ICl. The kinetic plots for the decay of the dimer radical cation in the presence and absence of the salts show that the decay is predominantly due to the neutralization with Cl−. The lengthening of the lifetime of the dimer radical cation in the presence of (C6H5)2IPF6 is believed to be due to the stabilization toward Cl− by the ion‐pair formation with PF6−. Slow formation of the dimer radical cation was also observed in the presence of (C6H5)2IPF6, which is attributable to the oxidation of radical species by the salt followed by the charge transfer to monomer. Such a slow formation of radical cation in the presence of (C6H5)2IPF6 was confirmed with biphenyl in methylene chloride.
Pyrolysis of polyacetylene
Authors: Chien James C. W. , Uden Peter C. , Fan Ju‐Li
Published: April 2003

Thermal degradation of polyacetylene has been studied by pyrolysis gas chromatography mass spectrometry (PGC–MS). The most abundant product is benzene, but significant quantities of other products are also produced. In decreasing order of yield, these are methane, ethylene, propylene, ethane, butadiene, toluene, and xylenes. A simple mechanism capable of accounting for most of the observed products is random chain scission followed by electron–proton exchanges and in some cases ring closure. The total material balance between proton‐rich and proton‐depleted products is within 10%.
Relationship between polymer solution fluidity and concentration. I. Empirical equations established
Authors: Chen Shou‐Zhong
Published: April 2003

From a great deal of experimental data we obtained an empirical equation for polymer solution fluidity and concentration:

This equation is more linear than conventional equations that relate polymer solution viscosity and concentration. The equation of the initial concentration parameter γ is applicable over a wider concentration range:
Electron transfer between insoluble dihydronicotinamide polymer and insoluble benzoquinone polymer
Authors: Tsubokawa Norio , Endo Takeshi , Okawara Makoto
Published: April 2003

The electron transfer between insoluble polymer containing 1‐benzyl‐1,4‐dihydronicotinamide (BNAH) structure (P‐BNAH) and benzoquinone (Q) structure (P‐Q) by use of alloxan (A) as an electron carrier was investigated. Although no reaction occurred on suspending the P‐BNAH and P‐Q in ethanol/water, P‐Q was reduced smoothly to hydroquinone structure (P‐HQ) by addition of A. The results suggest that A was reduced by P‐BNAH to give A radical (A·) or dialuric acid (D) and then A· (or D) reduced P‐Q, whereby A was regenerated and thus indicated that the oxidation reduction between insoluble solid polymers was mediated by A as an electron carrier.
Binding of methyl orange and its homologs by polyion complex in ethylene glycol
Authors: Takagishi Toru , Kozuka Hiroshi , Kim Gong Ju , Kuroki Nobuhiko
Published: April 2003

The extent of binding of methyl orange, ethyl orange, propyl orange, and butyl orange by a polyion complex, which consists of equimolar sodium polymethacrylate and a piperidinium cationic polymer, was measured in ethylene glycol at 25, 30, and 35°C. The effects of aqueous and nonaqueous media on the binding of the dye by the polymer matrix were compared. In ethylene glycol only noncooperative binding (Langmuir type) was observed, whereas two modes of binding, noncooperative and cooperative, were involved in the aqueous environment. The first binding constants and the thermodynamic parameters associated with the binding in ethylene glycol were evaluated. The polymer matrix exhibited a higher affinity toward the dye in ethylene glycol than in water at low concentrations of free dye and bound these anionic cosolutes with different hydrophobicities but the same affinity as in ethylene glycol. These interactions are highly exothermic and characterized by relatively large negative entropy changes. Electrostatic forces are the principal contributors to the dye–polymer complex formation. The binding behavior observed in the nonaqueous solvent is reasonably accounted for in terms of disappearance of hydrophobic interactions between the dye and the polymer and an increase in electrostatic attraction between the anionic small molecule and the positively charged sites on the polyion complex.
Tribo‐ and photopolymerization of 9‐ethyl‐3‐vinylcarbazole crystals
Authors: Tazuke Shigeo , Supakorn Onusa , Inoue Takashi
Published: April 2003

Crystals of 9‐ethyl‐3‐vinylcarbazole(I) were easily polymerized to high polymer under mechanical shear stress and photoirradiation without initiator. The degree of polymerization was higher for tribo‐ than for photopolymerization. It was concluded that the mechanism of polymerization was cationic for both polymerizations on the basis of additive effects. The polymerization behavior depended on the recrystallizing solvents. Ethanol crystals are less sensitive to tribo‐ and photo‐polymerization than those of n‐hexane or benzene. X‐ray diffraction patterns of I also differed, depending on the recrystallizing solvents. The reactive crystals were in a high energy state, as revealed by DSC analysis. Similarities of photo‐ and tribopolymerization and comparative studies of tribopolymerization with triboluminescence of I indicated that polymerizations are likely to be induced by an identical reactive intermediate tentatively considered as a zwitterionic species.
The degradation and stabilization of polyacrylonitrile. I. Evidence for β‐ketonitrile defect structures as initiators of degradation
Authors: Ayrey G. , Chadda S. K. , Poller R. C.
Published: April 2003

The theory that β‐ketonitrile structures initiate discoloration reactions in polyacrylonitrile has been tested by a number of methods. Using radiochemical techniques the numbers of carbonyl groups in various polymers have been measured as have the amounts of combined water. A model β‐keto compound, 1,3,7,‐tricyanoheptan‐4‐one was synthesized and its reactions studied. None of these experiments supported the idea that β‐ketonitrile structures are of primary importance in initiating the degradation of polyacrylonitrile.
Thermotropic liquid crystalline polymers. II. Further examples on their synthesis by the interaction of poly(acryloyl chloride) with mesogenic compounds
Authors: Paleos C. M. , Margomenou‐Leonidopoulou G. , Filippakis S. E. , Malliaris A. , Dais Photis
Published: April 2003

A recently reported method for the synthesis of thermotropic liquid crystalline polymers by the interaction of reactive polymers with mesogenic compounds is further illustrated by the preparation of two mesomorphic polymers. Specifically, poly(acryloyl chloride) is esterified withp‐hydroxybiphenyl andp‐hydroxyazobenzene for the synthesis of poly(p‐biphenyl acrylate) and poly(p‐acryloyloxyazobenzene), respectively. The liquid crystalline character of both polymers was established by optical microscopy, x‐ray diffraction analysis, and differential scanning calorimetry.
Glow discharge polymerization of chlorine‐containing fluoromethane
Authors: Inagaki N. , Kimura K. , Minamidani T. , Katsuura K.
Published: April 2003

Glow discharge polymerization in the CF2Cl2/CH4, CHF2Cl, and CHFCl2 systems was performed. The materials formed are not polymers but oligomers; they contain considerable chlorine and fluorine and their surface energies are not so low as those of the polymers from the CF4/CH4 mixture. These materials dissolved in organic solvents and their molecular weights were measured. In glow discharge polymerization of methylmethacrylate the addition of CHFCl2 caused formed polymers to be soluble in organic solvents. This polymerization is discussed.
Effect of quaternized poly(4‐vinyl pyridine) on the cleavage of threonine catalyzed by pyridoxal or pyridoxal phosphate
Authors: Nakano Hidehiko , Yamane Ryuji , Sangen Osamu , Yamamoto Yoshitake
Published: April 2003

The effect of poly(4‐vinyl pyridine) quaternized with ethyl bromide (C2PVP) on the cleavage of threonine catalyzed by pyridoxal (PL) of pyridoxal phosphate (PLP) with metal ion was investigated. When PLP was used with Cu2+, Al3+, Fe3+, or VO2+C2+PVP showed marked stimulation, whereas the stimulation was small when PL was used with each of these metal ions. The stimulation by C2PVP was reduced in the presence of 0.1M KCI. To account for this stimulation we suggested the contribution of the electrostatic interaction between C2PVP and phosphate moiety of PLP. The introduction of hydrophobicity into the polymer by quaternizing partially with dodecyl bromide did not improve the stimulation. With Co2+ or Zn2+, or without multivalent cation, a similar effect of C2PVP on the catalysis of threonine cleavage by PLP was shown, although the reaction rate was low, but with Ni2+ C2PVP did not affect the reaction catalyzed by PL or PLP.
Aqueous polymerization of methyl methacrylate initiated by peroxydisulfate–citric acid redox system catalyzed by silver ion
Authors: Dash Sudhansu Bhusan , Baral Nilambar , Pati Nrusingha C. , Nayak Padma L.
Published: April 2003

The kinetics of the aqueous polymerization of methyl methacrylate initiated by potassium peroxydisulfate–citric acid catalyzed by silver ion was investigated in nitrogen atmosphere. The rate of polymerization is proportional to the square root of peroxydisulfate concentration. The initial rate increases with increasing citric acid concentration up to 15 × 10−3M, after which it decreases. The rate of polymerization also increases initially with monomer concentration and decreases at higher monomer concentration. The effects of temperature and the addition of some solvents and salts on the rate of polymerization have also been studied and a suitable kinetic scheme has been proposed for the reaction.
Synthesis of polymer intermediates containing the hexafluoroisopropylidene group via functionalization of 2,2‐diphenylhexafluoropropane
Authors: Lau K. S. Y. , Landis A. L. , Kelleghan W. J. , Beard C. D.
Published: April 2003

The title compound was synthesized by hydrogenolysis of its precursor 2,2‐bis(4‐trifluoromethanesulfonatophenyl)hexafluoropropane (2) in the presence of a base. 2,2‐Diphenylhexafluoropropane (6) can be appropriately functionalized at the 3,3′‐positions to give the diamino (7), dibromo (11), dicarboxaldehydo (13), 3‐ethynyl‐3′‐carboxaldehydo (14) derivatives which are important monomers in the synthesis of various high‐temperatures resistant polymers and oligomers containing the hexafluoroisopropylidene (6F) group. 2,2‐Bis(4‐triflatophenyl)hexafluoropropane (2) undergoes quantitative dinitration at the 3,3′‐positions to yield 2,2‐bis(3‐nitro‐4‐triflatophenyl)hexafluoropropane (3) which ultimately leads to the 3,3′‐diamino‐4,4′‐bis(arylamino) (5) and 3,3′‐diamino‐4,4′‐dihydroxy (8) derivatives which are specifically designed for phenylbenzimidazole, benzimidazoquinazoline, and benzoxazole polymers and oligomers.
The action of a benzotriazole light stabilizer in wool. I. A diffuse reflectance analysis of UV screening
Authors: Leaver Ian H.
Published: April 2003

A procedure based on diffuse reflectance spectroscopy was developed to determine the UV screening effect of a benzotriazole light stabilizer in wool fabric. Expressions that enable the protective effect of the stabilizer to be calculated directly from reflectance data were derived. The dependence of the screening effect on additive concentration was deduced from measurements of fabric reflectivity in the wavelength range of 300–400 nm. Two reflectometers with quite different optical geometries were used to measure the reflectance spectra and the merits of the two systems are discussed. A theoretical expression for the optical screening phenomenon in highly scattering materials was evaluated for substrates of different reflectivity and the general implications of this relationship are considered.
Functional polymers. XIX. Biuret oligomers and polymers of biologically active primary aliphatic amines
Authors: Purgett Mark D. , Deits Walter , Vogl Otto
Published: April 2003

Biuret oligomers and polymers from primary aliphatic amines and aromatic or aliphatic diisocyanates have been synthesized. To demonstrate the feasibility of the synthesis of polybiurets, aliphatic primary amines with n‐propyl, n‐hexyl, n‐octyl, and n‐dodecyl groups have been incorporated. For the synthesis of biuret oligomers of biologically active primary aliphatic amines [8‐(4‐amino‐1‐methylbutylamino)‐6‐methoxyquinoline] (primaquine) and adamantanamine were selected. Primaquine was also incorporated into polyepichlorohydrin by nucleophilic substitution of the chlorine of the chloromethyl group by the primary aliphatic amino group of primaquine. The structure of the biuret polymers was established by elemental analysis, and by infrared 1H‐ and 13C‐NMR spectroscopic characterization. Several attempts to use primaquine as a diamine for the formation of condensation polymers, including reaction of primaquine with sebacoyl chloride (to form polyamides), or with diisocyanates (to form polyureas) were unsuccessful.
Radiation‐induced oxidation of polyethylene, ethylene–butene copolymer, and ethylene–propylene copolymer
Authors: Arakawa Kazuo , Seguchi Tadao , Watanabe Yuhei , Hayakawa Naohiro
Published: April 2003

Oxygen consumption and yield of oxidation products during γ‐irradiation were studied on five types of polyethylene (PE), ethylene–butene copolymer (EB), and ethylene–propylene copolymer (EPR) using gas chromatography, mass spectrography, and high‐resolution NMR. Samples were irradiated in oxygen under pressure from 0 to 500 torr by 60Co γ‐rays up to 20 Mrad at 22–25°C. In enough oxygen, oxygen consumption and yield of oxidation products are independent of oxygen pressure for low‐density PE, EB, and EPR. The G values of oxygen consumption were 14–18.4 for PE, 11.6 for EB at 1 × 106 rad/h, and 8.3 for EPR at 2 × 105 rad/h. The oxidation products determined were carboxylic acid (CH2COOH), H2O, CO2, and CO. The oxygen consumption and oxidation products for PE were found to increase with increasing crystallinity.
Phthalocyanine polymers. IV. Novel type of thermally stable polyimides derived from metal phthalocyanine tetramines and benzophenone tetracarboxylic dianhydride
Authors: Achar B. N. , Fohlen G. M. , Parker J. A.
Published: April 2003

Poly(metal phthalocyanine)imides of copper, cobalt, nickel, and zinc were synthesized by the reaction of metal phthalocyanino tetramines with benzophenone tetracarboxylic dianhydride. These polymers were characterized by elemental analyses and IR, TGA, and inherent viscosity studies. Noteworthy features of these phthalocyanine polymers are their remarkable thermal and thermooxidative stabilities with char yields at 800°C that range from 78 to 83% in a nitrogen atmosphere. The relative thermal stabilities of these polymers have been evaluated by activation energy measurements.
New telechelic polymers and sequential copolymers by polyfunctional initiator‐transfer agents (inifers). XVIII. Epoxy and aldehyde telechelic polyisobutylenes
Authors: Kennedy J. P. , Chang V. S. C. , Francik W. P.
Published: April 2003

This article concerns the synthesis and characterization of new epoxy and aldehyde telechelic polyisobutylenes, that is,
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and . The synthesis of the epoxy derivative was achieved by quantitative epoxidation of α,ω‐di(isobutenyl) polyisobutylene with m‐chloroperoxybenzoic acid and that of the dialdehyde by quantitative isomerization of the epoxy termini with zinc bromide. Infrared (IR) and 1H‐NMR analysis of these new telechelic polymers and ultraviolet (UV) analysis of the 2,4‐dinitrophenylhydrazine derivative of the dialdehyde indicate quantitative conversions and yields, that is, essentially theoretical functionalization (Fn = 1.95 ± 0.05).
Radical‐initiated homo‐ and copolymerization of α‐methylene‐γ‐butyrolactone
Authors: Ueda Mitsuru , Takahashi Masami , Imai Yoshio , Pittman Charles U.
Published: April 2003

The kinetics of α‐methylene‐γ‐butyrolactone (α‐MBL) homopolymerization was investigated in N,N‐dimethylformamide (DMF) with azobis(isobutyronitrile) as initiator. The rate of polymerization (Rp) was expresed by Rp = k[AIBN]0.54[α‐MBL]1.1 and the overall activation energy was calculated as 76.1 kJ/mol. Kinetic constants for α‐MBL polymerization were obtained as follows: kp/kt1/2 = 0.161 L1/2 mol−1/2·s−1/2; 2fkd = 2.18 × 10−5 s−1. The relative reactivity ratios of α‐MBL(M2) copolymerization with styrene (r1 = 0.14, r2 = 0.87) were obtained. Applying the Q–e scheme led to Q = 2.2 and e = 0.65. These Q and e values for α‐MBL are higher than those for MMA
Radical‐initiated homo‐ and copolymerizations of methacryloyl fluoride
Authors: Ueda Mitsuru , Kumakura Toshihisa , Imai Yoshio , Pittman Charles U.
Published: April 2003

The kinetics of methacryloyl fluoride (MAF) homopolymerization was investigated in methyl ethyl ketone (MEK) with azobis(isobutyronitrile) as initiator. The rate of polymerization (Rp) followed the expression Rp = k[AIBN]0.55[MAF]1.18. The overall activation energy was calculated as 74.4 kJ/mol. The relative reactivity ratios of MAF(M2) copolymerization with styrene (r1 = 0.083, r2 = 0.14), and methyl methacrylate (r1 = 0.48, r2 = 0.81) in methyl ethyl ketone were obtained. Application of the Q–e scheme (in styrene copolymerization) led to Q = 2.22 and e = 1.31. The glass transition temperature (Tg) of poly(MAF) was 90°C by thermomechanical analysis. Thermogravimetry of poly(MAF) showed a 10% weight loss of 228°C in air.
Effect of temperature conditions on the mechanism of formation, molecular structure, and properties of polyurethanes
Authors: Dorozhkin V. P. , Kimelblat V. I.
Published: April 2003

The formalized kinetic approach to the mechanism of urethane formation in the system of prepolymer with end NCO groups–1,4‐butanediol together with the dispersion analysis of kinetic curves have helped to establish that, at moderate temperatures, the mechanism may be represented by a scheme comprising a noncatalytic stage of urethane formation and a catalytic one including the formation of a double complex of a catalyst with an isocyanate or a hydroxyl group. As the temperature rises the proportion of the noncatalytic stage decreases significantly, while a mechanism, including the formation of the triple complex isocyanate group–catalyst–hydroxyl, becomes the most probable. It has been shown that the formation of a triple complex at elevated temperatures is thermodynamically more advantageous than the formation of double complexes; hence these changes of mechanism with temperature. It has been found that the temperature conditions of polyurethane production greatly affect the degree of its branching. Two crosslinked polyurethanes were obtained, one under the temperature conditions providing for the minimum degree of branching, the other under isothermal conditions. It has been discovered that the degree of branching of a prepolymer may greatly affect the density of chemical and physical bonds and a range of physical and chemical properties of the polyurethane.
Structure and polydispersity of some poly(methyl methacrylates) prepared by different methods
Authors: Moustafa A. B. , Badran A. S. , Ebdon J. R. , Hunt B. J.
Published: April 2003

Poly(methyl methacrylate) has been prepared under various conditions of monomer, initiator, reaction medium, and temperature. All the 13C‐NMR spectra for the polymers obtained were those to be expected for radically initiated poly(methyl methacrylates) of conventional, slightly syndiotactic‐rich microstructures prepared at normal temperature. The spectra were found to be very similar to that for a radical poly(methyl methacrylate) first analyzed by Inoue et al.,8 and to those of poly(methyl methacrylates) prepared in earlier experiments of this general type. The ratios of isotactic (mm) to heterotactic (mr and rm) to syndiotactic (rr) triads were found to be close to 5:34:61. It can be concluded from the 13C‐NMR spectra that the propagation steps in these polymerizations are of conventional radical type, and are uninfluenced from the steric point of view by nature of the polymerization medium by the presence of the various additives. The polydispersity for some poly(methyl methacrylate) samples determined by gel permeation chromatography was found here to vary rather widely and ranges between 1.9 and 7.9.
The validity of the compound concentration scale for the interpretation of some crosslinked polyolefine properties
Authors: Kunert Krzysztof A.
Published: April 2003

In our earlier investigations of chemically crosslinked polyethylene and polypropylene we based our interpretation of the properties of these polymers on the compound concentration scale.1–4 To check the validity of this scale we performed some NMR experiments on crosslinked polypropylene and compared the results with the gel scale.
Kinetic models of homogeneous ionic polymerization
Authors: Chen Gan‐Tang
Published: April 2003

Based on modern concepts of ionic polymerization, a system of kinetic models which covers various initiation and propagation mechanisms, all based on a pseudo‐steady‐state assumption, is proposed. Special attention is given to the effect of solvent on the rate‐controlling steps. Equations for reaction rate, degree of polymerization, and molecular weight distribution for 12 fundamental models are derived and fully discussed. The theory is also extended to more complicated systems such as the ion pair, free‐ion system.
Copolymerization of unsaturated spiro ortho esters with maleic acid derivatives
Authors: Fukuda Hiroyuki , Hirota Masahiro , Endo Takeshi , Okawara Makoto , Bailey William J.
Published: April 2003

The formation of charge‐transfer (CT) complexes of unsaturated spiro ortho esters such as 2‐methylene‐1,4,6‐trioxaspiro[4.4]nonane(I) and 2‐methylene‐1,4,6‐trioxaspiro[4.6]undecane(II) with maleic acid derivatives such as maleic anhydride (Manh), dimethyl maleate (DMM), and N‐ethyl maleimide (NEM) was ascertained by ultraviolet (UV) and nuclear magnetic resonance (NMR) spectroscopy. The stoichiometries of these complexes were estimated as 1:1. The determination of their equilibrium constants (K) was attempted by using the Hanna‐Ashbough equation with NMR spectroscopy. Although K values for I‐DMM and II‐DMM were specified as 0.266 and 0.336 L/mol, respectively, those for the other systems could not be obtained but were assumed to be negligible small (K ≪ 1). Copolymerization of these systems which was carried out without an initiator determined that spontaneous copolymerization occurs in all cases but that the copolymerization rates of I‐DMM and II‐DMM systems are slow. The systems in which Manh or DMM was used as an acceptor monomer gave the alternating copolymers at various monomer to feed ratios. The terpolymerizaton of the I–Manh–DMM system established that DMM takes little part in giving the alternating copolymers I and Manh. Consequently, it was assumed that the reactivity of the CT complex monomer is dependent on the contribution of the dative structure to CT complex.
Synthesis of poly‐ϵ‐caprolactone via a free radical mechanism. Free radical ring‐opening polymerization of 2‐methylene‐1,3‐dioxepane
Authors: Bailey William J. , Ni Zhende , Wu Shang‐Ren
Published: April 2003

2‐Methylene‐1,3‐dioxepane 6 polymerized with a quantitative ring opening to form poly‐ϵ‐caprolactone via a free radical mechanism. On the other hand, 2‐methylene‐1,3‐dioxolane (ethylene ketene acetal) 4 and 2‐methylene‐1,3‐dioxane 5, under the same conditions, generated polymers with mixed ring‐opened and nonring‐opened structures. In copolymerization monomer 6 also showed a high tendency toward ring opening by which the ester functionality could be conveniently introduced into the backbone of the addition polymers.
Ethynyl‐terminated polysulfones: Synthesis and characterization
Authors: Hergenrother P. M.
Published: April 2003

Hydroxy‐terminated polysulfones (PSs) of number‐average molecular weights from 3000 to 26,000 g/mol were converted to the corresponding 4‐ethynylbenzoate–terminated PS through a three‐step synthesis. The initial step involved the reaction of the hydroxy precursor with 4‐bromobenzoyl chloride followed by displacement of the bromo group with trimethylsilylacetylene using a palladium catalyst. The trimethylsilyl group was subsequently cleaved with a weak base to afford the ethynylbenzoate‐terminated PS. A more direct route to the ethynylbenzoate‐terminated PS involved the reaction of the hydroxy‐terminated PS with 4‐ethynylbenzoyl chloride. The trimethylsilylethynyl and ethynyl groups undergo a thermally induced reaction to provide modified PS with better solvent resistance and higher apparent glass transition temperatures than an unmodified linear PS. The physical properties of the modified PS are compared with those of a linear PS.
Molecular orbital study of the Q–e scheme in free radical copolymerization
Authors: Colthup Norman B.
Published: April 2003

Molecular orbital calculations were used to study free radical polymerization. Calculations show that the monomer is activated during the reaction and the pi bond becomes a diradical. The radical on the carbon that is about to form the new bond is called the e radical in this article. The other is the Q radical. For different monomers it is shown indirectly that changes in the energies of formation of the Q and e radicals are related to changes in the Q and e terms in the empirical Q–e scheme of Alfrey and Price. The polar effect in the Q–e scheme involves the e‐radical, unpaired electron density. Specifically, the Q–e sum (ex + ey) is correlated with the e radical spin density. Also the e term is correlated with the electron density on the unsubstituted carbon of the monomer. The relationship of the Q radical to the adjacent substituent is shown by correlating ln Q values with the energy of addition of a hydrogen atom to a monomer. These relationships give theoretical meaning to the Q–e terms and allow calculation of Q and e values from molecular orbital properties for small monomers.
Polymerization of methyl methacrylate by a charge transfer mechanism with urea and iron (III) complex
Authors: Hussain S. , Dass N. N.
Published: April 2003

Methyl methacrylate (MMA) can be polymerized by a charge transfer complex formed by the interaction of urea, methyl methacrylate, and carbon tetrachloride (CCl4) in a nonaqueous solvent like dimethylsulfoxide (DMSO). The rate of polymerization can be accelerated by Lewis acids like Fe3+. This article reports the polymerization of MMA initiated by urea and CCl4 and accelerated with hexakisdimethylsulfoxide iron (III) perchlorate, [Fe(DMSO)6](ClO4)3, and A at 60°C. Definite induction periods were observed for the polymerization reaction initiated by urea and CCl4 alone, but the induction period completely vanished when the molar ratio of urea to A reached 6:1. The molecular weights of the polymers with 6:1 molar ratio of urea to A were higher than with urea alone. The rate constant for the polymerization of MMA in the presence of [Fe(urea)6]3+ was 1.03 × 10−5 1 mol−1 s−1 at 60°C. The transfer constant for CCl4 for polymerization with urea alone is 2.43 × 10−3 at 60°C.
Dehydrochlorination of poly(vinyl chloride) by aqueous sodium hydroxide solution under two‐phase conditions
Authors: Kise Hideo
Published: April 2003

The reaction of poly(vinyl chloride) powder with aqueous sodium hydroxide solution in the presence of quaternary ammonium or phosphonium halides yielded dehydrochlorinated products of conjugated polyene structure. The reaction was discussed in terms of a phase transfer catalytic mechanism between aqueous and polymer phases. Among the catalysts used tetrabutylammonium bromide was the best. To obtain the optimum conditions the effects of reaction temperature, the concentration of NaOH and the catalyst, and the molecular weight of poly(vinyl chloride) were investigated. Treatment of PVC films and solutions in tetrahydrofuran with aqueous NaOH solutions under two‐phase conditions also produced dehydrochlorinated films and powders.
Reaction rate of crosslinkings by using a metallated polymer. III. Solvent effects on rate constants of grafting and intramolecular crosslinking reactions.
Authors: Ishizu Koji , Ohtaka Atsushi , Fukutomi Takashi , Kakurai Toshio
Published: April 2003

Lithium‐metallated (styrene‐p‐benzylstyrene)copolymer was reacted with chlorine‐terminated polystyrene as a crosslinker polymer in a mixture of tetrahydrofuran (THF)–n‐hexane at 25°C in the presence of lithium chloride(LiCl). The rate constants were estimated from the changes in the concentration of metallated polymer by photometrical measurements. As a result, the rate constant of grafting (k1) showed a constant value in spite of a change in molecular weight of the crosslinker polymers and the addition of n‐hexane. The rate constant of intramolecular crosslinkings (k2intra) obtained in a mixed solvent (21 ∼ 36 vol % of n‐hexane) increased when the molecular weight of the crosslinker polymers and the extent of n‐hexane were increased.