bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polymerization of fluorinated diacetylenes
Authors: Baum Kurt , Cheng Paul G. , Hunadi Ronald J. , Bedford Clifford D. 
Published: April 2003

AbstractPerfluoroalkylene diacetylenes, HCC(CF2)nCCH, underwent thermal polymerization at 250–350°C to give glassy polymers stable to 450°C. Partial polymerization of the volatile monomers gave oligomers that are processable at atmospheric pressure. Polymers with similar thermal stability were obtained by transition‐metal‐catalyzed polymerization of the monomers at moderate temperatures.
Synthesis and characterization of acrylated phosphonates and their polymers having 1,3‐dioxolane and 1,3‐dioxane moieties derived from brominated cyclic acetals of polyols through the Arbuzov reaction. II
Authors: Sahni Suresh K. , Cabasso Israel 
Published: April 2003

AbstractGlycerol, D‐mannitol, and D‐sorbitol were converted into their mono‐ and di‐O‐1,3‐dioxolane and 1,3‐dioxane bromoethylidene derivatives through a transacetalation reaction with bormoacetaldehyde diethyl acetal under controlled conditions. These brominated dioxolane or dioxane derivatives were subsequently phosphonylated through the Arbuzov reaction. The phosphonylated cyclic acetals were used as precursors for the synthesis of acrylated phosphonate monomers. All these compounds have been characterized by elemental analysis and spectroscopic (IR, 1H‐,13C‐, 31P‐NMR and mass) methods. A mixture of 1,3‐dioxane and 1,3‐dioxolane derivatives was obtained with D‐sorbitol, whereas the reaction products with glycerol and D‐mannitol yielded primarily the 1,3‐dioxolane derivatives. The acrylated phosphonates of glycerol and mannitol have been polymerized and studied on the basis of gel permeation chromatography and their spectral and thermal properties. The acrylated phosphonates, monomers, and polymers, were shown to have a large capacity to solvate and dissolve heavy metal salts. This results in a dramatic increase (> 100°C) of the glass transition temperature of these polymers.
Liquid–crystalline copoly(ester–amide)s prepared from hydroxybenzoic and 4‐aminobenzoic acids
Authors: Chen Wen‐Hsin , Chang Teh‐Chou , Higashi Fukuji 
Published: April 2003

AbstractCopolycondensations of 3,5‐dimethoxy‐4‐hydroxybenzoic (syringic acid, SGA), 4‐hydroxybenzoic(PHB), and 4‐aminobenzoic (PAB) acids with diphenyl chlorophosphate(DPCP)/LiCl/pyridine were studied. Random copolycondensations of a wide range of monomer compositions afforded copolymers exhibiting birefringence at room temperature. However, when the sequence of PHB and PAB was fixed by using a newly prepared monomer, 4‐(4′‐aminobenzoyloxy) benzoic acid (PABBA), the ordered copolymers thus prepared showed birefringence above 200°C, but not at room temperature. Variations in solubility and thermal behavior were also observed in randomly and sequentially prepared copolymers. The monomer sequences in copolymers in random copolycondensations could be changed by controlling the reaction of monomers with DPCP.
Oxidation of polyethylene surface by corona discharge and the subsequent graft polymerization
Authors: Iwata Hiroo , Kishida Akio , Suzuki Masakazu , Hata Yoshio , Ikada Yoshito 
Published: April 2003

AbstractOxidation of a polyethylene (PE) surface by corona discharge and the subsequent graft polymerization of acrylamide (AAm) were studied. The maximum amount of peroxides introduced by corona treatment at a voltage of 15 kV was about 2.3 × 10−9 mol cm−2. The decomposition rate of peroxide and the dependence of graft amount on the storage period of the corona‐treated PE films showed that there were several kinds of peroxides, the labile one being mainly responsible for the initiation of graft polymerization. When the corona‐treated film was brought into contact with a deaerated aqueous solution of AAm, graft polymerization took place more strongly with the treatment time, but was reduced after passing a maximum. Although the x‐ray photoelectron spectroscopic analyses of the corona‐treated PE films showed homogeneous oxidation of the outer polymer surface by corona discharge, optical microscopy on the cross section of the grafted film revealed the graft polymerization to be limited to a very thin surface region.
Polymer drying, 1. Time‐studies of desorption from liquid saturated poly(styrene‐co‐divinylbenzene) microparticles
Authors: Errede L. A. , Kueker M. J. , Tiers G. V. D. , Van Bogart J. W. C. 
Published: April 2003

AbstractTime studies of evaporation from liquid‐saturated poly[(Sty)98‐co‐(DVB)2] particles enmeshed in poly(tetrafluoroethylene) microfibers show that it is possible to distinguish kinetically between volatile sorbed molecules not absorbed to the polymer chain and those that are adsorbed to it. Elimination of the nonadsorbed molecules occurs first, and it follows zero‐order kinetics. The subsequent elimination of the residual volatiles, namely the adsorbed molecules, follows first‐order kinetics, with a rate constant that remains constant only until the enmeshed microparticles undergo transition from the gel to the glass state. Thereafter, is observed a sequence of up to six independent rate constants in a series of intervals, the durations of which increase exponentially. This is interpreted to mean that after evaporation to the glass transition composition, the total weight of residual adsorbed molecules is given by a linear combination of exponential decay functions for up to six populations of adsorption sites, the rate constants for which reflect the force of association between the sites and the retained molecules.
Binding methyl orange and hydrophobic fluorescent probes by poly(2‐dimethylaminoethyl methacrylate) and copolymers of 2‐dimethylaminoethyl methacrylate and N‐vinyl‐2‐pyrrolidone: pH dependence of the binding and fluorescence intensity
Authors: Takagishi Toru , Hosokawa Toshitsugu , Hatanaka Yasumichi 
Published: April 2003

AbstractThe pH dependence of the interaction of poly(2‐dimethylaminoethyl methacrylate) and copolymers of 2‐dimethylaminoethyl methacrylate and N‐vinyl‐2‐pyrrolidone with methyl orange, 2‐p‐toluidinylnaphthalene‐6‐sulfonate (TNS), and 1,6‐diphenyl‐1,3,5‐hexatriene (DHT) was studied by equilibrium dialysis and fluorescence measurements at pH's 7–10. The first binding constant accompanying the binding of methyl orange and TNS by the polymers, in particular the homopolymer, shows a maximum around pH 8 and maximal fluorescence intensity of TNS is obtained around pH 8.5 in the presence of the polymers. To elucidate these observations the pH‐induced conformational changes of the homopolymer were examined by potentiometric titration and viscosity measurements and the thermodynamic parameters that accompany the binding were calculated. The polymer was found to change from an extended coil at lower pH to a compact coil at higher pH. The electrostatic attraction between the sulfonate group of the small molecule and the protonated nitrogen atoms on the polymer is increased at lower pH and the hydrophobic interaction between the hydrophobic moieties of the polymer and the small molecule is enhanced at higher pH. The results obtained for the dye binding and fluorescence intensity were discussed in terms of the electrostatic and hydrophobic interactions.
Studies on polymerization of vinyl acetate using ylide as an initiator and degradative transfer agent
Authors: Shukla A. K. , Saini S. , Kumar P. , Rai J. S. P. , Srivastava A. K. 
Published: April 2003

AbstractThe polymerization of vinyl acetate initiated by β‐picolinium‐p‐chlorophenacylide was carried out at 30, 35, and 40°C, using the conventional dilatometric technique. The initiator and the monomer exponent values were 0.80 ± 0.15 and unity, respectively. The polymerization was inhibited in the presence of hydroquinone, but was favored by nonpolar solvent and polymerization temperature. The energy of activation was 90.3 kJ mol−1. An average value of k/kt for the present system was found to be 0.37 × 10−2 L mol−1 s−1. The results are explained in terms of radical mode of polymerization with degradative initiator transfer; the principal mode of termination, however, was biomolecular.
Copolymerization of isobutylene with 1,4‐13C‐isoprene
Authors: Kuntz Irving , Rose Kenneth D. 
Published: April 2003

AbstractCopolymers of isobutylene with 1,4‐13C‐isoprene have been prepared in methyl chloride solvent at −90 to −50°C using aluminum chloride and organoaluminum halide initiators. The examination of these copolymers containing 0.5 to 3.0 mol % of the diolefin by 13C‐NMR has given new information about the mechanism of the copolymerization. It appears that every macromolecule ends in an isoprene derived unit; that chain transfer to monomer by an isoprene‐derived propagating carbocation is the dominant chain breaking process. The copolymer triad sequences have been unambiguously assigned and analyzed in both batch and continuous stirred tank reactor copolymers. The relative concentrations of the triads agree with those predicted by published reactivity ratios.
Modification of polymers via electrophilic aromatic substitution
Authors: Mallakpour Shadpour E. , Butler George B. 
Published: April 2003

AbstractThree vinyl monomers, 2,4,6‐trimethoxystyrene, 4‐(N,N‐dimethylamino)styrene, and N‐methyl‐2‐vinylpyrrole, were synthesized via the Wittig reaction from the corresponding aldehyes. These monomers were homopolymerized by radical polymerization using α,α′‐azoisobutyronitrile (AIBN) as initiator at 60°C. The reaction of these polymers with 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione (phTD) and 4‐methyl‐1,2,4‐triazoline‐3,5‐dione (MeTD) was investigated. Although polytrimethoxystyrene reacts slowly with PhTD at room temperature, the other two polymers react fast and lead to the incorporation of the triazolinedione unit into the side chain of the polymer via electrophilic aromatic substitution. The reaction of bistriazolinediones (BTD) with these polymers was performed in dimethylformamide using 10–20% molar concentration of the BTD. The resulting crosslinked polymers are insoluble in polar as well as nonpolar solvents. Some physical properties of the unmodified and modified polymers were studied.
Copolymerization and interaction of acrylonitrile and indene
Authors: Mikhael M. G. , Mokhtar S. M. , Saad G. R. , Naoum M. M. , Elsabee M. Z. 
Published: April 2003

AbstractThe donor–acceptor interaction of acrylonitrile (AN) with indene (In) has been investigated by means of ultraviolet spectroscopy and dielectric polarization measurements. The latter method yielded a value of 0.5 for the association constant of the charge‐transfer‐complex (CTC) and a 4.02 D for its dipole moment. The copolymerization of the two monomers was characterized by a tendency towards alternation when conducted in the bulk. This might be due to the participation of a weak CTC in the process of copolymerization. However, this tendency disappeared in polar solvents such as DMF.
The solid state photobleaching and photocrosslinking of copolymers containing the anthracene chromophore
Authors: Hargreaves John S. 
Published: April 2003

AbstractCopolymers of methyl methacrylate with an anthracene derivative are photodegraded in the solid state to give crosslinked material. The mechanism of insolubilization is dependent on the nature of the substituents at both the 9 and 10 positions of the anthracene chromophore. Photodimerization is the primary and most efficient cause of insolubilization if one of these positions is unsubstituted. Photodimerization does not occur if both of these positions are substituted; instead crosslinking is caused by photolysis of the endoperoxide of the parent anthracene. Bromination can sensitize the initial photooxidation and subsequent crosslinking in a copolymer where photodimerization does not occur. As a consequence of the crosslinking the rate of photobleaching of the anthracene chromophore by 1ΔgO2 is severly curtailed. Poly(methyl methacrylate), a positive‐tone polymer when exposed to UV light, is made negative acting by the incorporation of bound anthracene chromophores.
Thermally stable polymers based on bismaleimides containing amide, imide, and ester linkages
Authors: Melissaris Anastasios P. , Mikroyannidis John A. 
Published: April 2003

AbstractSeven new structurally different bismaleimides were synthesized and characterized by infrared and proton nuclear magnetic resonance spectroscopy. The chain of these polymer precursors was extended by incorporating amidized, imidized, and esterified 4‐chloroformyl phthalic anhydride. The bismaleimides containing amide and imide linkages were prepared by a simple synthetic route based on the reaction of the monomaleamic acid derived from various aromatic diamines (1 mol) with 4‐chloroformyl phthalic anhydride (0.5 mol) and subsequent cyclodehydration of the intermediate triamic acid. In addition, chain extended bismaleimides were prepared by reacting the monomaleamic acid derived from p‐phenylenediamine with several dianhydrides such as p‐phenylene bis(trimellitamide anhydride), p‐phenylene bis(trimellitate anhydride), and bis‐phenol A bis(trimellitate anhydride). The differential thermal analysis scans of bismaleimides showed exotherms at 221–304°C associated with their polymerization reactions. The thermogravimetric analysis traces of polymers did not show a weight loss up to 351–393 and 344–372°C in N2 and air atmospheres, respectively. The anaerobic char yield of polymers at 800°C was 44–61%. These polymers can be used for fabrication of composites having improved properties.
Copolymerization of 2‐methylene‐4‐phenyl‐1,3‐dioxolane with electrophilic vinyl monomers through zwitterionic mechanism
Authors: Yokozawa Tsutomu , Takagi Jun , Endo Takeshi 
Published: April 2003

AbstractSpontaneous copolymerization of cyclic ketene acetal, 2‐methylene‐4‐phenyl‐1,3‐dioxolane (I) with common electrophilic vinyl monomers, such as methyl α‐cyanoacrylate (MCA), acrylonitrile (AN), and methyl methacrylate (MMA) were investigated to further explore zwitterion polymerization method with cyclic ketene acetals. In the reaction of I with MCA and AN, spontaneous copolymerization took place at ambient temperature. The copolymers of I with MCA gave low molecular weight polymers, but copolymers obtained with I and AN were high molecular weight polymers. In the reaction of I and MMA, high molecular weight copolymer was obtained only at temperatures above 80°C. Thus, obtained polymers were not the alternating copolymers and possessed high I content in all the cases. From the above results, macrozwitterionic mechanism was suggested as discussed.
Aspects of degradation and stability of ABS copolymers. I. Effect of β‐carotene as antioxidant
Authors: Abdel‐Razik E. A. 
Published: April 2003

AbstractThe oxidative degradation of polybutadiene–styrene–acrylonitrile (ABS) copolymer was extensively investigated. Three factors were studied: the influence of ageing temperature on the rate of the oxidation of the copolymer; the efficiency of β‐carotene as chain breaking antioxidant; and the effect of butadiene content on the rate of the oxidative degradation of the ABS copolymer.
Copolymerization of styrene with maleic anhydride initiated by thiol compounds
Authors: Kuramoto Noriyuki , Iwaki Takeshi , Satoh Akihiro , Nagai Katsutoshi 
Published: April 2003

AbstractCopolymerization of styrene (ST) with maleic anhydride (MAH) initiated by thiol compound was investigated under various conditions. The kinetics of copolymerization of ST with MAH initiated by p‐toluenethiol (pTT) was studied in dioxane in the temperature range of 25–60°C, and the rates (Rp) of copolymerization and activation energy were determined. Rp was found to depend on [pTT],0.6 ([ST] + [MAH])2.7. The overall energy of activation was 10.8 kcal/mol in the temperature range of 25–60°C. A mechanism involving the formation of a complex between MAH and pTT the decomposition of which yields the initial radical is suggested.
New polymer syntheses 22. LC‐poly(esterimide)s derived from trimellitic acid, ω‐amino acids and hydroquinone or 4,4′‐dihydroxybiphenyl
Authors: Kricheldorf Hans R. , Pakull Ralf , Buchner Stefan 
Published: April 2003

AbstractDiacids with variable spacer length were prepared by condensation of trimellitic anhydride and ω‐amino acids. From these diacids, homopolyesters were prepared by thermal condensation with the acetates of hydroquinone or 4,4′‐dihydroxy biphenyl and a series of copolyesters containing 4‐hydroxy benzoic acid. The same LC poly(ester imide)s could also be prepared in a “one‐pot procedure” from trimellitic anhydrid, lactams, and bisphenol acetates. The differential scanning calorimetry (DSC) traces of most poly(ester imide)s exhibit two endotherms representing the solid → LC phase transition (Tm1) and the LC phase → isotropic melt transition (Tm2). Observation under the polarizing microscope and wide‐angle X‐ray scattering (WAXS) measurements suggest that the LC phase formed immediately above the melting points (Tm1) have a smectic character. Poly(ester imide)s of 4,4′‐dihydroxybiphenyl possess higher melting points and a broader temperature range of the LC phase than those of hydroquinone. The copolyesters possess a nematic melt over a broad temperature range. Thermomechanical analyses under low pressure (0.05 kg/mm2) gave heat distortion temperatures close to the melting points (Tm1), and under high pressure (1 kg/mm2), values between Tm1 and the glass transition temperatures (Tg). Thermogravimetric measurements indicate that processing from the melt is feasible up to temperatures around 340°C.
Synthesis and polymerization of multiallyl monomer in matrix of poly(methacryloyl chloride)
Authors: Jantas R. , Połowiǹski S. , Podešva J. 
Published: April 2003

AbstractBy reacting poly(methacryloyl chloride) (PMKC) with allyl amine, a multiallyl monomer in PMKC matrix has been obtained. Free‐radical polymerization of multiallyl monomer in diluted solutions at a concentration of 12 g/L multiallyl monomer occurs partly along ordered allyl units in the matrix and results in ladder‐type branched polymers. The polymers obtained are soluble in alcohols, DMF, DMSO and have unreacted allyl double bonds. The structures of multiallyl monomer and homopolymer have been found on the basis of elemental analysis, IR and 1H‐NMR spectra and an examination of the products of hydrolysis. The effect of the reaction of degradative chain transfer on the structure of the polymer obtained has been discussed.
Electropolymerization of benzene and biphenyl in organic media: Influence of different parameters (solvent, water, acidity, salt) on the formation of polyparaphenylene films (PPP)
Authors: Aeiyach S. , Lacaze P. C. 
Published: April 2003

AbstractThe electrosynthesis of polyparaphenylene films (PPP) by oxidation of benzene or biphenyl on a Pt electrode was studied in different organic media. Film formation was possible only if the solvent had acidic properties according to the Lewis concept, and if the water content of this medium was less than 5 × 10−2M. Addition of an excess of P2O5 or CuCl2 into the medium increased the acidity and improved the adherence and the homogeneity of the films considerably. PPP films were electroactive and conductive if the electrolysis was carried out in the presence of salts containing BF, SbF, PF anions; they were insulating with perchlorate salts. IR analysis of these polymers showed highly crosslinked structures and the chains were constituted of about 10 para coupled phenyl moieties.
13C‐NMR study of arylene–ether–ketone copolymers
Authors: Havens John R. , Reimer Karen B. 
Published: April 2003

AbstractThe chemical microstructure of arylene–ether–ketone copolymers of terephthaloyl chloride (TCl), 1,4‐diphenoxybenzene (DPB), and diphenyl ether (DPE) has been characterized by 13C‐NMR. Copolymers synthesized via two Friedel–Crafts reaction have been investigated; the first reaction uses HF and BF3 to catalyze polymerization, and the second uses LiCl to moderate the activity of the Lewis‐acid catalyst, AlCl3. The HF/BF3 approach results in random copolymers, in which the TCI displays no preference in reacting with either DPB or DPE. The buffered AlCl3 approach yields somewhat blocky copolymers, in which the DPB and DPE tend to segregate. The degree of segregation in these materials has been quantified by formulas for the number‐average block lengths.
Polyamides containing arylene sulfone ether linkages
Authors: Idage S. B. , Idage B. B. , Shinde B. M. , Vernekar S. P. 
Published: April 2003

AbstractPolyamides containing arylene sulfone ether linkages were synthesized from 4,4′‐[sulfonylbis(p‐phenyleneoxy)] dibenzoyl chloride (SPCI), 3,3′‐[sulfonylbis(p‐phenyleneoxy)] dibenzoyl chloride (SMCl), and arylene sulfone ether diamines (SED), by solution and interfacial polymerization techniques. In solution polymerization, the effect of various acid acceptors such as propylene oxide (PO), lithium chloride (LiCl)/lithium hydroxide (LiOH), and triethylamine (TEA) on molecular weight of the polyamides was studied. The effect of methyl substituted and unsubstituted aromatic sulfone ether diamines on molecular weight and thermal properties of polyamides was also studied. The polyamides prepared were characterized by solution viscosity, elemental analysis, thermal gravimetric analysis, differential scanning calorimetry, and x‐ray diffraction. Physical and thermal properties of polyamides prepared from SPCl and SED were compared with the polyamides prepared from SMCl and SED.
A study of the graft copolymerization of methacrylic acid onto starch using the H2O2/Fe++ redox system
Authors: Vázquez B. , Goñi I. , Gurruchaga M. , Valero M. , Guzmán G. M. 
Published: April 2003

AbstractGraft copolymerization of methacrylic acid (MetAc) onto potato starch using H2O2/Fe++ redox system was investigated. The best conditions of the grafting reaction were determined and several variables were studied: initiator and monomer concentrations, time, and temperature. Percent grafting efficiency, percent grafting, percent grafted monomer conversion, and total conversion were obtained. The optimum graft yield was obtained at 7.3 × 10−3M H2O2 concentration and it was favored by increasing the methacrylic acid concentration and reaction time.