bluuebunny/crossref_metadata_2025 huggingface dataset:
Cinnamates. III. The light sensitive polymers: Cinnamates with internal charge‐transfer spectroscopic properties
Authors: Pa̧czkowski Jerzy , Toczek Maria , S̀cigalski Franciszek , Ćwiklińska Danuta , Sierocka Michalina
Published: April 2003

In this paper, we outline the photochemical and spectroscopic properties of a new light‐sensitive polymer obtained as a result of polystyrene modification by attachment of a pendant 4‐dimethylamino‐cinnamate ester group. This specific cinnamate displays typical charge‐transfer character in the absorption and emission spectra. The photochemical and photophysical properties of photopolymer are compared with the monomeric model photochemistry and photophysics.
Synthesis and ESCA surface studies of octadecyl chain‐extended polyurethanes
Authors: Rahman Ron , Ratner Buddy D.
Published: April 2003

Poly(ether urethane)s as biomaterials display certain favorable mechanical and biocompatibility properties. Earlier studies suggest that improved blood compatibility might be attained by introducing hydrocarbon groups at the surface. We synthesized and characterized a series of polyurethanes in which a N‐2,3‐dihydroxypropyl‐N′‐octadecyl urea chain extender (ODCE) was incorporated into the poly(tetramethylene glycol) (PTMO)/4,4′‐methylenebis(phenylene isocyanate) (MDI) system. Molecular weights of the polymers varied between 40,000 and 250,000. An electron spectroscopy for chemical analysis (ESCA) study of the ODCE polyurethane surface revealed a substantially enhanced hydrocarbon concentration compared to a control PTMO/MDI/ethylene diamine (ED) polyurethane surface. Also, bulk composition analyses and ESCA data of the ODCE polymers indicated that the percentage of carbon was higher in the surface region than in the bulk. Thus, the ODCE polymer showed a marked increase in hard‐segment concentration in the surface region compared to the bulk region and to the ED polymer.
Electroinitiated polymerization of acrylamide in nonaqueous media
Authors: Balasubramanian T. R. , Mahadevan V.
Published: April 2003

Anodic electroinitiated polymerization of acrylamide has been studied in DMF and DMSO in the presence of Co(NO3)2 or Co(ClO4)2 in the temperature range 25–40°C. The kinetics and mechanism of the process has been investigated as a function of variables and a suitable mechanism proposed. From the experimental observations, the rate of polymerization is seen to be proportional to [AM]1.5, [I]0.5, and [Co2+]1. Current densities exceeding 15 mA/cm2 have no effect on the rates. The average degrees of polymerisation (P̄n) increase with increasing [AM] and decreasing [Co2+] and applied current, I. It has been shown that a monomer‐metal ion complex is oxidized at the anode, generating radical species. The polymerization and termination are confined to the anode compartment. The process is very efficient compared to the NO mediated reaction.
Polymerization of bis(2‐oxazoline) compounds with dicarboxylic acids
Authors: Sano Yasuo
Published: April 2003

A side reaction was found in the reaction of a 2‐oxazoline compound with a carboxylic acid. It is an oxazoline ring opening addition to an amide group formed by the main reaction. In addition, certain phosphites were found to act as catalyst for the side reaction. The rate constants of the main and side reactions in the system of 2‐phenyl‐2‐oxazoline andn‐octanoic acid were obtained through simulation of the reactions on an analog computer. The side reaction makes it impossible for a very high molecular weight polymer to form in the reaction of a bis‐2‐oxazoline with a dicarboxylic acid, but makes it possible for a new crosslinked polymer to form when excess bis‐2‐oxazoline and a dicarboxylic acid are heated in the presence of a certain phosphite.
Synthesis of polyphthalocyanines by an oxido‐reduction reaction initiated by the benzhydrol functional group. II. Polymer study
Authors: Pascal Thierry , Malinge Jean , Sillion Bernard
Published: April 2003

Three new bis(phthalonitrile) monomers carrying flexible aliphatic polyether sequences were synthesized and thermally polymerized to yield crosslinked poly(metal‐free phthalocyanine) networks. The procedure of thermal conversion of bis(phthalonitrile) monomers involved an oxidoreduction reaction initiated by the alcohol functional group of a benzhydrol phthalonitrile coreactant. The phthalocyanine polymeric networks were characterized by FT‐IR, TGA, TMA, and x‐ray diffraction. Their electrical dc conductive properties were studied in a pure and an iodine‐doped state.
Electron transfer function of kerateine gel and conjugated redox reaction by using the kerateine‐immobilized membrane
Authors: Nakamura Yoshiharu , Yamada Masaru , Miura Jun'ichiro , Hirota Koji , Hori Teruo
Published: April 2003

Kerateine gel, prepared by reducing wool keratin with alkaline 2‐mercaptoethanol‐urea solution and by partially reoxidizing the dissolved kerateine, reduced iron(III) to iron(II). Reduction of iron(III) was enhanced by addition of copper(II). Reduction of methylene blue (MB) to leuco MB with thioglycollic acid (TGA) as a model compound of wool thiol group was investigated in the presence of copper(II) and intercuticular cementing material (δCu) extracted from wool fiber. It is confirmed that copper(II) is a catalyst for the reduction of MB and the δCu containing copper ion acts as a carrier for electron transfer.

Some kerateine/δCu‐immobilized hydrophilic polyurethane membranes were prepared. A conjugated redox reaction combining the reduction of MB and the oxidation of TGA was carried out across these membranes.
Living cationic polymerization of vinyl ethers with a functional group. VII. Polymerization of vinyl ethers with a silyloxyl group and synthesis of polyalcohols and related functional polymers
Authors: Higashimura Toshinobu , Ebara Kenji , Aoshima Sadahito
Published: April 2003

Living cationic polymerizations of two silicon‐containing vinyl ethers, 2‐(t‐butyldimethyl‐silyloxyl)ethyl vinyl ether (tBuSiVE) and 2‐(trimethylsilyloxyl)ethyl vinyl ether (MeSiVE), have been achieved with use of the hydrogen iodide/iodine (HI/I2) initiating system in toluene at −15 or −40°C, despite the existence of the acid‐sensitive silyloxyl pendants. The living nature of the polymerizations was demonstrated by linear increases in the number‐average molecular weights (M̄n) of the polymers in direct proportion to monomer conversion and by their further rise upon addition of a second monomer feed to a completely polymerized reaction mixture. The polymers obtained in these experiments all exhibited very narrow molecular weight distributions (MWD) with M̄w/M̄n around or below 1.1. Desilylation of the polymers under mild conditions (with H+ for MeSiVE and F− for tBuSiVE) gave poly(2‐hydroxyethyl vinyl ether), a water‐soluble polyalcohol with a narrow MWD. The living processes also permitted clean syntheses of amphiphilic AB block copolymers and water‐soluble methacrylate‐type macromonomers, all of which bear narrowly distributed segments of the polyalcohol derived from the silicon‐containing vinyl ethers.
Synthesis and characterization of phenolic hydroxyl terminated phenylquinoxaline oligomers
Authors: Labadie Jeff W. , Hedrick James L.
Published: April 2003

The synthesis of phenylquinoxaline oligomers of predictable molecular weight and with phenolic hydroxyl functional end groups is reported. The synthetic procedure utilizes 4‐hydroxybenzil as a substituted monofunctional monomer in a conventional PPQ synthesis to both control molecular weight and introduce the functional end groups. The molecular weights of the oligomers were determined by derivatization of the hydroxyl end groups with 3‐(trimethylsilyl)propionyl chloride, followed by 1H‐NMR analysis. Comparison of the integration of the trimethylsilyl resonance to the aromatic resonances allowed calculation of the number average molecular weight. A plot of log(η) vs. log(Mn) correlated well with that reported for high molecular weight PPQ. The end groups influenced the solubility behavior of the oligomers in chlorinated solvents, possibly due to hydrogen bonding. The oligomers were chain‐extendable to high molecular weight, confirming their suitability for utilization in copolymerizations to prepare phenylquinoxaline‐based block copolymers.
Zerovalent metal polymer composites. II. Metal–polymer microdispersions
Authors: Warshawsky A. , Upson D. A.
Published: April 2003

Metallization of water‐soluble polymers incorporating metal‐binding ligand is achieved by binding palladium ions at substoichiometric quantities, followed by reduction to polymer–zero‐valent palladium complex and deposition of transition metal ions by electroless plating solutions. The polymers studied include poly[N,N,N‐trimethyl‐N‐(m‐ and p‐vinylbenzyl)ammonium chloride], poly‐L‐glutamic acid, poly‐L‐lysine, and a copolymer of 2‐phenylhydroquinone‐2‐amino‐phthalic acid. Noble metal polyelectrolyte solutions were directly reduced with dimethylamineborane to stable microdispersions. The reactive nickel, cobalt and copper microdispersions were coated on KODAK ESTAR filmbase. Scanning electron microscopy (SEM), ESCA, and IR were used for material characterization. Conductivity and magnetic properties were also measured. Hydrophobic materials such as graphite and fluorinated graphite were metallized in organic solvents using hydrophobic trioctylammonium–tetrachloropalladate as the activating noble metal complex. The metallized conductive graphites were evaluated for their electrochemical properties.
Zerovalent metal polymer composites. III. Metallization of metal oxide surfaces with the aid of metallized functional polymer microdispersions
Authors: Warshawsky A. , Upson D. A. , Ferrar W. T. , Monnier J. R.
Published: April 2003

The adsorption of poly[N‐(m‐ andp‐vinylbenzyl)‐N,N,N‐trimethylammonium tetrachloropal‐ladate] complex on inorganic oxide surfaces followed by reduction of the palladium salt to form a catalytically active zerovalent metal polymer composite dispersed on the oxide surface and further deposition of transition metals, e.g., nickel, cobalt, and copper, by “additive” or “subtractive” deposition from electroless plating solutions is described. γ‐Ferric oxide was used as a template for such intermetallic replacement reactions, providing materials with controlled amounts of metal. Multimetallic catalysts based on aluminum oxide, zinc oxide, lanthanum oxide, magnesium oxide, and silica were prepared. Iron oxide modified by subtractive deposition of rhodium and iridium on nickel‐clad iron oxide were evaluated in Fischer–Tropsch carbonylation reactions leading from synthesis gas to alkanols.
Interpenetrating polymer network from castor oil‐based polyurethanes and poly(methyl methacrylate). XV
Authors: Patel Prashant , Suthar Bhikhu
Published: April 2003

The polyurethanes have been prepared from 2.12 functional OH containing castor oil and diphenyl methane diisocyanate under identical experimental conditions with a varying NCO/OH ratio. These polyurethanes were swollen in methyl methacrylate and subsequently interpenetrated by free radical polymerization using benzoyl peroxide and crosslinker ethylene glycol dimethacrylate. A series of interpenetrating polymer network (IPN) PU/PMMA IPNs were obtained as films by a transfer moulding technique. These IPNs were characterized by their resistance to chemical reagents, thermal behavior, and mechanical properties. The morphology was shown by SEM and dielectric properties at different temperatures were measured.
Poly[3,3‐bis(hydroxymethyl) oxetane]—an analog of cellulose: Synthesis, characterization, and properties
Authors: Vandenberg E. J. , Mullis J. C. , Juvet R. S.
Published: April 2003

Poly[3,3‐bis(hydroxymethyl)oxetane], PBHMO, was prepared in high molecular weight (ηinh up to 5.2) by polymerizing the trimethylsilylether of 3,3‐bis(hydroxymethyl)oxetane with the i‐Bu3Al–0.7 H2O cationic catalyst at low temperature, followed by hydrolysis. PBHMO is crystalline, very high melting (314°C) and highly insoluble, much like its analog, cellulose. It is soluble in 75% H2SO4 at 30°C, being 65% converted to the acid sulfate ester; these conditions are useful for viscosity measurement, since the degradation rate is low and at least an order of magnitude less than for cellulose in this solvent. PBHMO can be prepared as oriented films and fibers using the lower melting diacetate (184°C) which can be melt or solution (CHCl3) fabricated and then the oriented forms saponified to oriented PBHMO. BHMO can be directly polymerized to low molecular weight, perhaps somewhat branched, PBHMO (ηinh 0.1) with trifluoromethanesulfonic acid catalyst at room temperature. Poly(3‐methyl‐3‐hydroxymethyloxetane), (PMHMO), prepared in high molecular weight (ηinh up to 3.8) by the same method used for PBHMO, is more soluble and lower melting (165°C) than PBHMO, appears to be atactic and can be compression molded at 195°C to a tough, clear film which is readily oriented. Copolymers of BHMO with MHMO are crystalline over the entire composition range with a linear variation of Tm with composition, a new example of isomorphism in the polymer area.
Investigation of the thermal degradation of alkyl isocyanate polymers by direct pyrolysis mass spectrometry
Authors: Durairaj B. , Dimock A. W. , Samulski E. T. , Shaw M. T.
Published: April 2003

Thermal degradation mechanisms of alkyl isocyanate homo‐ and copolymers were studied using TGA and DP–MS. Both analyses showed that these polymers begin decomposing at around 190°C under inert or vacuum conditions. DP–MS analysis showed the formation of trace quantities of monomer from poly(butyl isocyanate) only and none from higher homologs. All polymers studied produced trimers as their principal decomposition product, implying that intramolecular cyclization is the dominant mechanism of decomposition.
Synthesis and properties of polyurethanes containing s‐triazine rings in the main chain
Authors: Sarwade Bhimrao D. , Wadgaonkar Prakash P. , Mahajan Sudhakar S.
Published: April 2003

Eight new diisocyanate monomers containing s‐triazine ring have been prepared from the parent diacids via the Curtius rearrangement of the corresponding diacyl azides. The parent diacids were synthesised by the reaction of p‐ and m‐hydroxybenzoic acid with 6‐methoxy‐2,4‐dichloro‐s‐triazine, 6‐phenoxy‐2,4‐dichloro‐s‐triazine, 6‐phenyl‐2,4‐dichloro‐s‐triazine, and 2‐diphenylamino‐4,6‐dichloro‐s‐triazine respectively. Polyurethanes have been synthesised by solution polymerization of these diisocyanates with ethylene glycol in N,N‐dimethylacetamide (DMAC). The resulting polymers were characterized by IR spectroscopy, viscosity measurement, solubility tests, and softening points.
Chemiluminescence studies of the low temperature thermooxidation of poly(phenylene sulfide)
Authors: Brauman S. K.
Published: April 2003

Chemiluminescence has been used to study the thermooxidation of poly(phenylene sulfide) film at 85–110°C in oxygen. To identify reaction products, the degraded surfaces were immediately analyzed by x‐ray photoelectron spectroscopy, then exposed to light and reanalyzed. In the proposed reaction sequence, thiyl radicals generated by oxidation of thiol end groups undergo chain transfer with polymer and bimolecular termination giving thiones, emitters that account for part of the chemiluminescence spectrum. Reaction is extensive at the surface, and subsequent exposure of the thermooxidized surface to light results in considerable loss of sulfur as well as carbon. The role of the thione products in subsequent degradation and chemiluminescence is discussed.
Living cationic polymerization of ethyl 2‐(vinyloxy)ethoxyacetate: A vinyl ether with an ether and an ester function in the pendant
Authors: Takeuchi Etsu , Hashimoto Tamotsu , Sawamoto Mitsuo , Higashimura Toshinobu
Published: April 2003

Ethyl 2‐(vinyloxy)ethoxyacetate (4; CH2CHOCH2CH2OCH2COOC2H5), a vinyl ether having both carboxylic acid ester and oxyethylene unit in its pendant, afforded well‐defined living polymers when polymerized by the hydrogen iodide/iodine (HI/I2) initiating system in toluene at −40°C. The polymers possessed a narrow molecular weight distribution (Mw/Mn ≤ 1.15), and their molecular weight (Mn) increased proportionally to monomer conversion or the molar ratio of the monomer to hydrogen iodide. The polymer molecular weight also increased upon addition of a fresh feed of the monomer to a completely polymerized reaction mixture. Polymers of high molecular weights (Mn > 5 × 105) and broad molecular weight distributions were obtained by BF3OEt2 in toluene at −40°C. Polymerization rate of 4 with HI/I2 is ca. 100 times greater than that of the corresponding alkyl vinyl ether, and thus 4 was found to be one of the most reactive vinyl ethers thus far studied. Alkaline hydrolysis of the pendant ester groups of the polymers gave a vinyl ether‐based polymeric carboxylic acid 6 with a narrow molecular weight distribution.
The mechanism of copolymerization of maleic anhydride with styrene and with vinyl acetate
Authors: Brown Anthony Stuart , Fujimori Kiyohisa , Craven Ian E.
Published: April 2003

A nonaqueous potentiometric direct titration method was used to determine the composition diagrams for the copolymerization of maleic anhydride with styrene and with vinyl acetate in methyl ethyl ketone at 50°C. The data were analyzed using nonlinear least‐squares minimization routines to fit composition equations for the terminal, penultimate, and complex models directly. The applicability of each model to both systems were evaluated statistically. The penultimate model was found to best describe both systems, although in the case of the maleic anhydride/vinyl acetate system this was only a small improvement over the terminal model. Although significant comonomer complexation occurs in both systems, the complex model did not provide statistically significant improvement in fit to the data compared with the terminal model.
Poly(aryline imide)s as E‐beam resist: Sensitivity and resolution
Authors: Chien James C. W. , Gong B. M.
Published: April 2003

Polyamic acids synthesized from di‐trifluoromethyl methane bis(phthalic anhydride) and 4,4′‐diaminophenyl sulfone and 4,4′‐diaminophenyl ether were found to have excellent negative E‐beam resist properties. The best materials contain about 90% imidized structural units having sensitivities of 1.5–2.5 μC cm−2 and contrast of 1.0–1.3. Polyamic acid of pyromellitic dianhydride and 4,4′‐diaminophenyl sulfone imidized to 97% exhibits useful positive E‐beam resist properties. Radiation induces imidization or chain scission to alter the solubility of the resist polymers resulting in the formation of latent images.
Kinetic studies of grafting of maleic anhydride to hydrocarbon substrates
Authors: Sipos Anita , McCarthy Joan , Russell Kenneth E.
Published: April 2003

The kinetics of grafting of maleic anhydride to various hydrocarbon substrates has been investigated. Grafting to eicosane and squalane was effected in the pure hydrocarbons and in 1,2‐dichlorobenzene solution, while polyethylene was grafted only in solution. The initiator was 2,5‐dimethyl‐2,5‐di(t‐butylperoxy)‐3‐hexyne which has a half life of about 1 h at a typical reaction temperature of 150°C. At high concentrations of initiator (Ca. 0.02M), the rate of disappearance of maleic anhydride is linear with time. In the pure hydrocarbons the order with respect to initiator is close to 0.5. In squalane, the overall activation energy is 112 kJ mol−1; the average number of maleic anhydride molecules grafted per molecule of peroxide decomposed varies from 8 at high rates of initiation to 57 at low rates of initiation. The results are interpreted in terms of a chain mechanism, including a slow propagation step in which a succinic anhydride radical abstracts hydrogen from the same or a different chain. The same general mechanism is proposed for grafting of maleic anhydride to polyethylene and the hydrocarbons in 1,2‐dichlorobenzene solution.
Interpenetrating polymer networks of poly(2,6‐dimethyl‐1,4 phenylene oxide) and poly(urethane acrylate). I
Authors: Mengnjoh Paul C. , Frisch Harry L.
Published: April 2003

Simultaneous full and pseudo‐ interpenetrating polymer networks of poly(2,6‐dimethyl‐1,4 phenylene oxide) (PPO) and a poly(urethane acrylate) (PUA) have been synthesized and characterized by differential scanning calorimetry, ultimate mechanical properties, and electron microscopy. No evidence of phase separation was detected in both the full and pseudo‐ PPO/PUA networks. The networks exhibited a single glass transition temperature at all the compositions studied. A maximum in tensile strength to break was observed at 25 PPO/75 PUA composition by weight percent.
Synthesis and characterization of nylon‐grated polyphenylene ether
Authors: Chao H. S.‐I. , Hovatter T. W. , Johnson B. C. , Rice S. T.
Published: April 2003

Polyphenylene ether (PPE) resin (a homopolymer made from 2,6‐xylenol with an i.v. of 0.46) was reacted with phenyl acrylate, p‐substituted phenyl acrylates, and diphenyl fumarate in an extruder or in solution. The number of olefinic molecules that had been grafted onto the PPE backbone was determined by FTIR or NMR methods, and the grafting efficiency and mechanism were examined. The grafted PPE resins were used to promote the anionic polymerization of ε‐caprolactam, and the quantity and the composition of the PPE–nylon 6 copolymers isolated were correlated with the number of promoter groups attached to the PPE resin.
Surface modification of polymers. III. Grafting of stabilizers onto polymer films
Authors: Allmér K. , Hult A. , Rånby B.
Published: April 2003

Polypropylene, polystyrene, and polyethylene have been grafted with glycidyl acrylate and glycidyl methacrylate. After 5 min of grafting with UV irradiation, polystyrene was extensively grafted to 91% coverage of glycidyl acrylate according to ESCA, while polypropylene was grafted to only 50% coverage. With glycidyl acrylate the grafting depth is estimated to be 0.1 μm for PP and 0.23 μm for PS. Glycidyl methacrylate is grafted in a thinner layer than glycidyl acrylate. The stabilizers 2,4‐dihydroxybenzophenone, phenyl 4‐aminosalicylate, and 4‐amino‐2,2,6,6‐tetramethylpiperidine were attached to LDPE surfaces containing grafted glycidyl acrylate by opening of the epoxide bond. The reaction between epoxide and stabilizer is diffusion controlled at high concentrations of stabilizer. UV spectroscopy on an LDPE film grafted and reacted with 2,4‐dihydroxybenzophenone showed that 227 nmol stabilizer/cm2 was bound to the surface.
Study of the morphology of poly(methyl methacrylate) as polymerized by the redox system Ce(IV)–isopropyl alcohol
Authors: Fernández M. D. , Fernández M. J. , Guzmán G. M.
Published: April 2003

Methyl methacrylate has been polymerized in aqueous nitric acid at 30°C, with the redox system ceric ammonium nitrate–isopropyl alcohol as initiator. The gravimetric method has been used to follow the reaction. After a short induction period polymerization started, and conversion attained a maximum value with extent of reaction, whereas the ceric ion is exhausted. The size, distribution, and number of PMMA particles formed were measured by scanning electron microscope. From the electron micrographs it was found that the particles are formed over a short period, and that the particle size distribution seems to be determined by flocculation and coagulation of the particles, because these are not stabilized. Average‐molecular weight was found to increase at high conversions and the molecular weight distribution became broader as particle size increased. Particle size increased with conversion, whereas the number of particles remained constant.
Synthesis and characterization of bigraft copolymers based on grafted type peracid polymer
Authors: Huang Wen‐Kuei , Hsiue Ging‐Ho
Published: April 2003

In this study, a radiation‐induced copolymer, namely, polyethylene‐g‐acrylic acid and EVA‐g‐acrylic acid, in the form of a membrane, particulate, or tube was used as a substrate. The carboxyl groups of the grafted acrylic chains were oxidized into peracids. Optimal conditions for the oxidation, including the catalyst, reaction time, and temperature were investigated. Novel bigraft copolymers were then synthesized from the grafted polymeric peracid. A third component (e.g., 2‐hydroxyethyl methacrylate) was grafted through the decomposition of peracid groups. Abnormality in morphology of the acrylic acid grafted and HEMA bigraft membrane was investigated by SEM and TEM observation, which showed the levelling effect of the third component and manifested a third circular domain generated inside the membrane at high degree of grafting.
New heat‐resistant polymers derived from azomethine bismaleimides and maleimide‐terminated azomethine prepolymers
Authors: Mikroyannidis John A.
Published: April 2003

A novel class of bismaleimides containing azomethine linkages was synthesized by reacting the monomaleamic acid derived from an aromatic diamine with terephthaldehyde (TPA) in a molar ratio 2 : 1 and subsequent cyclodehydration. In addition, a series of maleimide‐terminated azomethine prepolymers (MTAPs) was synthesized. More particularly, 4,4′‐diaminodiphenylsulfone (DDS) reacted with TPA in nonstoichiometric molar quantities (2 : 1 or 5 : 4 or 8 : 7) to prepare amine‐terminated azomethine prepolymers (ATAPs). The latter reacted with maleic anhydride and then cyclodehydrated. Furthermore, a maleimide‐crosslinkable azomethine prepolymer (MCAP) was synthesized by reacting tris(3‐aminophenyl)phosphine oxide with an equimolar amount of maleic anhydride and subsequently with TPA. The polymer precursors were characterized by IR, 1H‐NMR, DTA, and inherent viscosity. The thermal stability of the cured resins was evaluated by TGA and IGA. The thermal properties of the cured resins derived from the MTAPs were compared with those of the ordinary polyazomethine prepared from the reaction of DDS with TPA. It was shown that crosslinking of these polymer precursors during their curing was attained both via the maleimide and azomethine double bonds.
Exactly alternating silarylene–siloxane polymers. VII. Thermal stability and degradation behavior of p‐silphenylene–siloxane polymers with methyl, vinyl, hydrido, and/or fluoroalkyl side groups
Authors: Dvornic Petar R. , Perpall Holly J. , Uden Peter C. , Lenz Robert W.
Published: April 2003

The thermal stability and degradation behavior of a series of nine different exactly alternating silphenylene‐siloxane polymers which contained methyl, vinyl, hydrido, 3,3,3‐trifluoropropyl, and tridecafluoro‐1,1,2,2‐tetrahydrooctyl side groups, or their combinations, were investigated by dynamic and isothermal gravimetric analyses in air and in nitrogen. Two distinctly different mechanisms were observed in these atmospheres: a complex multi‐step weight loss process in air and a single‐step process in nitrogen. In nitrogen all polymers produced black, insoluble, highly stable degradation residues which were characterized by high carbon content. In contrast, in air the nonfluorine containing polymers degraded to pure silica, while the fluoroalkyl substituted polymers may have formed fluorosilicates of unspecified structures. There appears to be no significant molecular weight effect on the thermal stability of these polymers, at least not above an Mw value of about 35,000. Isothermal investigations indicate that 300°C in air and 350°C in nitrogen may be possible upper use temperatures for the methylvinyl substituted, exactly alternating silphenylene–siloxane polymers for extended periods of time. A strong thermostabilizing effect by vinyl side groups on the degradation behavior of these polymers was established. The extent of stabilization depends on the content of vinyl units, but it can already be clearly seen at the 5 mol % vinyl level, and it increases exponentially with increasing vinyl concentration. In contrast to this behavior, by comparison with the parent all‐methyl substituted, exactly alternating silphenylene–siloxane polymers, the hydrido and fluroalkyl side groups reduce overall polymer thermal stability in terms of the degradation onset temperature, the temperature for 50% weight loss, and the amount of degradation residue. The presence of these groups also extends the later stages of the degradation processes to higher temperatures. Based on these and previous results, an order of stability is proposed as a function of the type of the substituent side groups for the thermal degradation of these polymers.
Synthesis of optically active polynucleotide analogs with poly(vinyl alcohol)s as backbones and adenine and 5‐bromouracil derivatives as pendants
Authors: Overberger C. G. , Chang Ji Young
Published: April 2003

The optically active polynucleotide analogs were prepared by grafting nucleic acid base derivatives onto poly(vinyl alcohol). The (R)‐ethyl 2‐(5‐bromouracil‐1‐yl)propanoate was obtained either by reaction of 5‐bromouracil sodium salt with (S)‐ethyl 2‐[(methylsulfonyl)oxy]propanoate or reaction of 5‐bromouracil with (S)‐ethyl lactate in the presence of triphenyl phosphine and diethyl azodicarboxylate. Subsequent hydrolysis of the ester is aqueous acid provided the optically pure (R)‐bromouracilypropanoic acid. The monomer model compounds were prepared by an esterification reaction of the pendant groups with 3‐pentyl alcohol in the presence of dicyclohexylcarbodiimide and a catalytic amount of 4‐pyrrolidinopyridine. Poly(vinyl alcohol) underwent reaction with the (R)‐bromouracilylpropanoic acid or the (R)‐adeninylpropanoic acid in the presence of dicyclohexylcarbodiimide and a catalytic amount of 4‐pyrrolidinopyridine. The resulting polymers were optically active and percents grafting were almost quantitative.
Preparation and characterization of phenyl and undecyl oxazoline block copolymers
Authors: Cai Gangfeng , Litt Morton H.
Published: April 2003

Undecyl and phenyl oxazolines were synthesized. They were copolymerized in different mole ratios using methyl nosylate as initiator. A series of di‐ and triblock copolymers with narrow molecular weight distributions as indicated by GPC were obtained. A three‐armed block copolymer was also obtained by using 1,3,5‐tris(bromomethyl)benzene as initiator. When the nonpolar undecyl block crystallized as a coating, the critical surface energy approached 21.0 dyn/cm, and the contact angle of water on the surface could be higher than 107°. The melting point increased as the chain length of crystallizable undecyl block increased, and the melting peak on DSC was very sharp when the length was equal to or longer than 25 monomer units. When these copolymers were coated on substrates, the work of adhesion with pressure sensitive adhesives was greatly reduced.
Nylon 6/polyisocyanurate interpenetrating polymer networks (IPNs)
Authors: Chang Wally L. , Frisch Kurt C. , Ashida Kaneyoshi
Published: April 2003

Two component interpenetrating networks (IPNs) of the SIN type (simultaneous interpenetrating networks), composed of a polyisocyanurate network and a star‐shaped nylon 6, were made. The overall polymerization rates and physical properties for reaction injection molding (RIM) have been studied by the quasi‐adiabatic process. In order to model the actual rapid molding conditions, time versus temperature reaction profiles were measured, and the relative rates of polymerization subsequently determined from these data.
Anionic polymerization of star‐shaped nylon 6 with a trifunctional initiator
Authors: Chang Wally L. , Frisch Kurt C. , Ashida Kaneyoshi
Published: April 2003

The anionic polymerization of ϵ‐caprolactam (CLM) has been shown to proceed at high reaction rate when catalyzed by metallic lactamates and initiated by acyllactams. The role of initiator and catalyst concentration on the process of ϵ‐caprolactam anionic polymerization has been explored, with the aim of selecting the most suitable experimental conditions for reaction injection molding (RIM). The overall polymerization rates and physical properties for reaction injection molding of star‐shaped nylon 6 homopolymer have been studied by the quasi‐adiabatic process. In order to model the actual rapid molding conditions, time vs. temperature reaction profiles were measured, and the relative rates of polymerization subsequently determined from these data.
Novel triblock siloxane copolymers: Synthesis, characterization, and their use as surface modifying additives
Authors: Yilgor Iskender , Steckle Warren P. , Yilgor Emel , Freelin R. Gary , Riffle Judy S.
Published: April 2003

Synthesis of novel triblock, polycaprolactone‐b‐polydimethylsiloxane (PDMS) and poly(2‐ethyl‐oxazoline)‐b‐PDMS copolymers were demonstrated. These materials were obtained via the ring‐opening polymerization of ϵ‐caprolactone or 2‐ethyl‐2‐oxazoline monomers by using organofunctionally terminated PDMS oligomers as initiators and comonomers. Segment molecular weights in these copolymers were varied over a wide range between 1000 and 2000 g/mol and the formation of copolymers with desired backbone compositions were monitored by 1H‐NMR spectroscopy and GPC. DSC and TMA studies showed the formation of two phase morphologies with PDMS (Tg, −120°C) and polycaprolactone (Tm, 50–60°C) or poly(2‐ethyl‐2‐oxazoline) (Tg, 40‐60°C) transitions respectively. The use of polycaprolactone‐b‐PDMS copolymers as surface modifying additives in polymer blends were also investigated. When these copolymers were blended at low levels (0.25–10.0% by weight) with various commercial resins such as, polyurethanes, PVC, PMMA, and PET, the resulting systems displayed silicone‐like, hydrophobic surface properties, as determined by critical surface tension measurements or water contact angles. The effect of siloxane content, block length, base polymer type and morphology on the resulting surfaces are discussed.
Aqueous polymerization of methyl methacrylate initiated by the redox system Ce(IV)–isopropyl alcohol. Kinetics and molecular weight
Authors: Fernández M. D. , Guzmán G. M.
Published: April 2003

Polymerization of methyl methacrylate was carried out in aqueous nitric acid in the temperature range 26–40°C, with the redox initiator system ceric ammonium nitrate–isopropyl alcohol. A short induction period was observed, as well as the attainment of a limiting conversion, and the total ceric ion consumption with reaction time. The reaction orders were 1/2 and 3/2 with respect to the IPA and monomer concentration, respectively, within the range (3–5) × 10−3Mof Ce(IV). But at lower Ce(IV) concentration (≤ 1 × 10−3M), the order with respect to monomer and Ce(IV) changed to 1 and 1/2, respectively. The rate of ceric ion disappearance was first order with respect to Ce(IV) concentration and (RCe)−1was proportional to [IPA]−1. Both the rate of polymerization and the rate of ceric ion consumption increase with rise in temperature. The average‐molecular weight can be controlled by variations in IPA, Ce(IV), and monomer concentrations, and in temperature. A kinetic scheme involving oxidation of IPA by Ce(IV) via complex formation, whose decomposition gives rise to a primary radical, initiation, propagation, and termination of the polymeric radicals by bimolecular interaction is proposed. An oxidative termination of primary radicals by Ce(IV) is also included.
Synthesis and cationic polymerization of substituted 2,3‐dihydrofurans
Authors: Kim Jin‐Bong , Cho Iwhan
Published: April 2003

Cationic polymerization of substituted 2,3‐dihydrofurans has been performed to investigate the substituent effect on the ring‐opening polymerization. 2‐Phenyl‐2,3‐dihydrofuran (III), 2‐methoxy‐5‐phenyl‐2,3‐dihydrofuran (Va), and 2‐ethoxy‐5‐phenyl‐2,3‐dihydrofuran (Vb) were synthesized and polymerized with BF3 etherate and AlCl3 as acid catalysts. Va and Vb ring‐opening polymerized well to give the polymers with benzoyl as pendant group which were formed via cationic rearrangement during the ring‐opening process, while III polymerized via simple opening of ethylenic double bond to form a polymer with the retention of tetrahydrofuran ring in the main chain. The nature of substituted cyclic vinyl ethers depending on substituents was also discussed.
The synthesis and solution properties of some rigid‐chain, water‐soluble polymers: Poly[N,N′‐(sulfo‐phenylene)phthalamide]s and poly[N,N′‐(sulfo‐p‐phenylene)pyromellitimide]
Authors: Vandenberg E. J. , Diveley W. R. , Filar L. J. , Patel S. R. , Barth H. G.
Published: April 2003

Poly[N,N′‐(sulfo‐phenylene)phthalamid]es and poly[N,N′‐(sulfo‐p‐phenylene)pyromellitimide] were prepared in water‐soluble form and were found to have unique solution properties, similar in some respects to xanthan. The polymer most investigated, poly[N,N′‐(sulfo‐p‐phenylene)terephthalamide] (PPT‐S), is produced as the dimethylacetamide (DMAC) salt by the solution polymerization of 2,5‐diaminobenzenesulfonic acid with terephthaloyl chloride in DMAC containing LiCl. The isolated polymer requires heating in water to dissolve; the resulting cooled solutions are viscous or gels at concentrations as low as 0.4%. They are highly birefringent, exhibit circular dichroism properties, and are viscosity‐sensitive to salt. Solutions of this polymer mixed with those of guar or hydroxyethyl cellulose give significantly enhanced viscosity. The polymer is relatively low molecular weight, ca. 5000 estimated from viscosity data. Some meta and para isomeric analogs of PPT‐S were prepared; these polymers have similar properties except they are more soluble in water, and higher concentrations are required to obtain significant viscosity. Poly[N,N′‐(sulfo‐p‐phenylene) pyromellitimide] (PIM‐S) was prepared similarly from 2,5‐diaminobenzenesulfonic acid and pyromellitic dianhydride. Its aqueous solution properties are similar to those of PPT‐S. It appears that these relatively low‐molecular‐weight rigid‐chain polymers associate in water to form a network that results in viscous solutions at low concentrations.
Synthesis of new polyamidoximes and their crosslinking by transition metal ions
Authors: Bicak Niyazi , Tunca Umit , Yagci Yusuf
Published: April 2003

Three new polyamidoximes (PAO) having appropriate functionalities to bind transition metal ions were prepared. The polymers were obtained by the reaction of dichlorooximino ethane with the corresponding diamine. Characterization and crosslinking of PAOs via coordination with transition metal ions such as Ni(II), Co(II), Cu(II), and UO2(II) are presented. The crosslinked polymer complexes exhibit good thermal stability. It was also found that both square planar and tetrahedral coordination structures are present in the crosslinked polymers.
The effect of the third component on butadiene–propylene alternating copolymerization catalyzed by vanadium–aluminum system
Authors: Su Dan , Yu Dingsheng , Hu Liping , Jiao Shuke
Published: April 2003

The effects of five ethers and four AliBu2OR's with varied R' on butadiene–propylene alternating copolymerization were investigated. It was found that by adding the proper third component, both the conversion and the catalytic efficiency could be increased. The effect of the third component on the valence state of vanadium ion was also studied. A model of the active center of the ternary‐component catalyst system was proposed.
Studies on graft copolymerization onto cellulose derivatives. XXIX. Photo‐induced graft copolymerization of methyl methacrylate onto chitin and oxychitin
Authors: Takahashi Akira , Sugahara Yasusato , Hirano Yutaka
Published: April 2003

Graft copolymerization of methyl methacrylate (MMA) onto chitin and oxidized chitin was carried out by a noncatalytic photo‐induced and a photo‐sensitized method. The isolation method of grafted chains without a decrease in their degree of polymerization (DP) by sulfuric acid hydrolysis and the effects of some factors on the conversion and the grafted chain length have been studied.

In case of the photo‐induced graft copolymerization, if a small amount of dimethylformaldehyde (DMF) is added in the polymerization system, the induction period is shortened and the degree of grafting and the apparent number of grafted chains increase. The degree of grafting and the apparent number of grafted chains of the oxidized chitin containing a small amount of CO groups are greater than those of the untreated chitin, but a further increase in CO groups decreases these values.

In the presence of this two species of the chitin samples, the polymerization reaction was carried out as functions of monomer and chitin concentrations. From these results, the mechanisms of the photo‐induced graft copolymerization were discussed. It is also clear that the conversion and the apparent number of grafted chains by the noncatalytic photo‐induced method are generally larger than those by the photo‐sensitized method, and the grafting activity with hydrogen peroxide (HPO) is higher than that with azobisisobutyronitrile (AIBN).
High photosensitivity in cis‐polyphenylacetylene films irradiated with 60Co γ‐ray
Authors: Mujie Yang , Jian Zhao , Aibing Li , Zhiquan Shen , Mingjian Zhang , Senhao Lin
Published: April 2003

This paper reports that 60Co γ‐ray irradiation can convert cis‐polyphenylacetylene (cis‐PPA) films prepared with rare‐earth coordination catalysts to highly photosensitive materials. The dependence of the photosensitivity on irradiation dose, preparation methods, and microstructure of the PPA films has been investigated by means of a potential discharge technique. The photosensitivity was enhanced with increasing irradiation dose. The critical dose to produce a light response was 5 × 103 Gy. The maximum surface potential discharge rate was 618 V/s, and the dark decay was approximately 2 V/s for cis‐PPA films irradiated with 60Co γ‐ray (dose: 2 × 105 Gy). The cis‐transoidal‐PPA and an electrophotographic photoreceptor device incorporating cis‐PPA showed a higher irradiation effect. The structure and properties of 60Co γ‐ray irradiated rare‐earth PPA films are similar to the unirradiated films.
Preparation and properties of aromatic polyamides from 5‐t‐butylisophthalic acid and various aromatic diamines
Authors: Yang Chin‐Ping , Oishi Yoshiyuki , Kakimoto Masa‐Aki , Imai Yoshio
Published: April 2003

Aromatic polyamides (aramids) having pendant t‐butyl group were synthesized by the direct polycondensation of 5‐t‐butylisophthalic acid with various aromatic diamines in N‐methyl‐2‐pyrrolidone (NMP) using triphenyl phosphite and pyridine as condensing agents. The aramids having inherent viscosities of 0.6–2.4 dL/g were obtained in quantitative yields. These polymers were readily soluble in various solvents such as NMP,N,N‐dimethylacetamide, dimethyl sulfoxide, and pyridine, and gave transparent, tough and flexible films by casting from the NMP solutions. The aramids had glass transition temperatures between 250 and 330°C, and started to lose weight around 350°C, with 10% weight loss being recorded at about 450°C in air.
Acid photogeneration from sulfonium salts in solid polymer matrices
Authors: McKean Dennis R. , Schaedeli Ulrich , MacDonald Scott A.
Published: April 2003

The major photoproduct from irradiation of triphenylsulfonium salts is a Brönsted acid. This photochemical process has been used in several polymer film applications where the acid is used for crosslinking of films or other acid catalyzed reactions. Despite the widespread application of these materials, very little is known about the efficiency of acid generation in polymer films or the extent of the catalytic chain. This paper describes the use of a merocyanine dye technique to analyze for acid production in polymer films. The amount of acid produced on irradiation can be determined by this method and the extent of the catalytic chain then be determined.
Alkoxy‐substituted diaryliodonium salt cationic photoinitiators
Authors: Crivello J. V. , Lee J. L.
Published: April 2003

This paper describes the synthesis and characterization of a series of (4‐alkoxyphenyl)phenyliodonium salts which are excellent photo‐ and thermal‐initiators for the cationic polymerization of vinyl and heterocyclic monomers. These compounds are easily prepared by straightforward synthetic techniques and display very good solubility and photoresponse characteristics which make them especially attractive for use in UV curing applications. Those compounds with alkoxy chains of eight carbons and longer are essentially nontoxic.
NMR study on microstructure of polymer produced by hydrosilation of styrene with poly(hydrogenmethylsiloxane)
Authors: Kuwae Yoko , Kushibiki Nobuo
Published: April 2003

The microstructure of the polymer formed by the hydrosilation of styrene with poly(hydrogenmethylsiloxane) was studied by 1H‐ and 13C‐NMR spectra. Two modes of addition in hydrosilation were found to occur randomly without the influence of the adjacent monomer unit by statistical analysis of sequence distribution of 29Si‐NMR spectrum.
Photocrosslinking of polyethylene. I. Photoinitiators, crosslinking agent, and reaction kinetics
Authors: Chen Yong Lie , Rånby Bengt
Published: April 2003

High density polyethylene has been photocrosslinked in the melt by using 4‐chlorobenzophenone (4‐CBP) as photoinitiator and triallylcyanurate (TAC) as crosslinking agent. Various factors affecting the crosslinking process (photoinitiator used and its concentration, irradiation temperature and time, atmosphere, UV light source, light intensity) were examined. By optimizing the irradiation conditions, it was found that samples up to 2 mm thick could readily be crosslinked to high gel content (≈ 90%) with satisfactory homogeneity within very short irradiation times (≈ 15 s). The kinetic analysis of the crosslinking process showed a linear relation between log S and log t (S is the sol fraction t is the irradiation time). An induction period was observed, the length of which decreased with increasing concentration of 4‐CBP and increasing light intensity. An upper limit of gel content was also found for long irradiation times at a level depending on the concentration of 4‐CBP. The crosslinking rate was proportional to the second order of light intensity at lower intensity and changed to first order at higher light intensity. A mechanism based on the recombination of chain radicals through both allyl and alkyl type radicals of TAC was proposed.
The electrochemical preparation of soluble electrically conducting polymers of 3‐methoxythiophene with narrow distributions of molecular weight
Authors: Lowen Stephen V. , MacInnes David , Funt B. Lionel
Published: April 2003

Solutions of 3‐methoxythiophene (MeOT) in dimethylformamide (DMF) were electrolyzed at controlled electrode potentials. The polymerizations were studied under homogeneous conditions in solutions in which the polymer was soluble in the medium, and no coating of the electrodes occurred. The reaction proceeded at high coulombic efficiency and a first order dependence on monomer concentration was observed. The molecular weights of the polymers were determined by gel permeation chromatography. All samples showed a narrow distribution of molecular weights, with Mw/Mn ranging from 1.01 to 1.07. The molecular weight was low (about 3000 Daltons) and did not change in magnitude during the course of the reaction from 10 to 86% conversion, or with change in electrode potential from 1.55 to 1.65 V vs. SCE. The data are interpreted on a model based upon the competitive formation of chemically unreactive bipolarons.