bluuebunny/crossref_metadata_2025 huggingface dataset:
Blends of bisphenol a polycarbonate and acrylic polymers. I. A chemical reaction mechanism
Authors: Debier D. , Devaux J. , Legras R.
Published: April 2003

The chemical reaction at high temperature (above 200°C) between PC and PMMA has been very recently highlighted. However, no clear reaction mechanism has been proposed to explain this phenomenon. We suggest a reaction mechanism following two steps. The first step consists of hydrolysis of the ester bonds of the PMMA leading to acid pendant groups. These acids can then either ring close into glutaric anhydride, or acidolyze the carbonate bonds of PC during the second step. At the same time, benzoic acid produced by PC degradation could further react with PMMA or acidolyze the carbonate groups leading to the crosslinking of the system. A satisfactory contact between the reacting units is a key point in the proces. Significant amounts of PC‐PMMA copolymer are obtained when the reaction is performed from a miscible system. On the contrary, no reaction occurs during melt mixing. Understanding the process enables us to specify the conditions, in which no chemical reaction takes place. In nonreactive conditions, PC/PMMA blends remain immiscible for several hours at 300°C. The thermodynamic UCST proposed in the literature is just an artifact due to the occurrence of the chemical reaction. © 1995 John Wiley & Sons, Inc.
Fully aromatic thermotropic liquid crystalline polyesters of 3‐phenyl‐4,4′‐biphenol with 4,4′‐benzophenone dicarboxylic acid
Authors: Bhowmik Pradip K. , Han Haesook
Published: April 2003

A series of fully aromatic, thermotropic polyesters, derived from 3‐phenyl‐4,4′‐biphenol (MPBP), nonlinear 4,4′‐benzophenone dicarboxylic acid (4,4′‐BDA), and various other comonomers was prepared by the melt polycondensation method and characterized for their thermotropic liquid crystalline behavior by a variety of experimental techniques. The homopolymer of MPBP with 4,4′‐BDA had a fusion temperature (Tf) at 240°C, exhibited a nematic liquid crystalline phase, and had a narrow liquid crystalline range of 60°C. All of the copolyesters of MPBP with 4,4′‐BDA and either 30 mol % 4‐hydroxybenzoic acid (HBA), 6‐hydroxy‐2‐naphthoic acid (HNA) or 50 mol % terephthalic acid (TA), 2,6‐naphthale‐nedicarboxylic acid (2,6‐NDA) and low Tf values in the range of 210–230°C, exhibited a nematic phase, and had accessible isotropization transitions (Ti) in the range of 320–420°C, respectively. As expected, each of them had a broader range of liquid crystalline phase than the homopolymer. They had a “frozen” nematic, glassy order as determined with the wide‐angle X‐ray diffraction (WAXD) studies. The morphology of each of the “as‐made” polyesters had a fibrous structure as determined with the scanning electron microscopy (SEM), which arises because of the liquid crystalline domains. Moreover, they had higher glass transition temperatures (Tg) in the range of 167–190°C than those of other liquid crystalline polyesters, and excellent thermal stabilities (Td) in the range of 500–533°C, respectively. © 1995 John Wiley & Sons, Inc.
Differences in structure growth in amine curing of diglycidyl ether of bisphenol a and N,N‐diglycidylaniline epoxy resins: Bifunctional models
Authors: Matĕjka Libor , Podzimek S̆tĕpán , Dus̆ek Karel
Published: April 2003

The reaction of diepoxides, diglycidylaniline (DGA), or diglycidyl ether of Bisphenol A (DGEBA) with aniline was followed using HPLC and SEC. The effect of molar ratio of reagents, dilution of the system, reaction temperature, and the difference between the reaction mechanisms for DGA and DGEBA systems on the reaction kinetics and molecular weight evolution is discussed. Molecular weights of the DGA‐aniline polymers were by an order of magnitude lower than those of the DGEBA‐aniline polymers due to the formation of small cyclic products in the former case. Also, a reduction in Mn with increasing temperature, dilution, and diluent polarity is brought about by a greater tendency toward cyclization under these conditions. Theoretically calculated molecular weight evolution during the reaction is in satisfactory agreement with the experiment. © 1995 John Wiley & Sons, Inc.
Effect of methyl groups on the thermal properties of polyesters from methyl substituted 1,4‐butanediols and 4,4′‐biphenyldicarboxylic acid
Authors: Loman Albert J. B. , van der Does Leen , Bantjes Adriaan , Vulic Ivan
Published: April 2003

Results are reported on the effect of lateral methyl groups on the thermal properties of a series of polyesters prepared from diethyl 4,4′‐biphenyldicarboxylate and various methyl substituted 1,4‐butanediols. The diols were 1,4‐butanediol; 2‐methyl‐1,4‐butanediol; 2,2‐dimethyl‐1,4‐butanediol; 2,3‐dimethyl‐1,4‐butanediol; 2,2,3‐trimethyl‐1,4‐butanediol; and 2,2,3,3‐tetramethyl‐1,4‐butanediol. Apart from the tetramethyl derivatve, the transition temperatures of the methyl substituted polyesters were lower with respect of the unsubstituted polyester. On the basis of polarized photomicrographs, a smectic A mesophase was found for the unsubstituted polyester, whereas a nematic mesophase was observed for the 2‐methyl substituted polyster. The 2,2‐dimethyl, 2,3‐dimethyl, and the 2,2,3‐trimethyl substituted polyesters showed no liquid crystalline behavior. The 2,2,3,3‐tetramethyl derivative displayed a birefringent melt phase although the DSC measurements were not unambiguous. A copolyester based on diethyl 4,4′‐biphenyldicarboxylate, 1,4‐butanediol, and 2,2,3,3‐tetramethyl‐1,4‐butanediol showed a broad nematic mesophase. Further evidence for the nematic mesophase of this copolyester and the 2‐methyl substituted polyester was provided by dynamic rheological experiments. Based on thermogravimetric analysis, it was concluded that the thermal stability was affected only when four methyl side groups were present in the spacer. © 1995 John Wiley & Sons, Inc.
Deep UV photoresists based on poly(dl‐tert‐butyl fumarate)
Authors: Crivello J. V. , Shim S.‐Y.
Published: April 2003

Poly(di‐tert‐butyl fumarate) was prepared and evaluated as a potential candidate as a deep UV photoresist. Although this polymer displayed excellent sensitivity, the polymer was found to exhibit poor dry etch resistance. Copolymers of di‐tert‐butyl fumarate with either allyltrimethylsilane or styrene, and an onium salt as a photoacid generator were synthesized and subsequently evaluated using a 248‐nm KrF excimer laser step‐and‐repeat system (stepper). At 248 nm, the absorbance of ∼ 1 μm thick resist films was only 0.156‐0.211. The sensitivities of these resists were 1‐4 mJ/cm2. The dry etch resistance of these photoresists was comparable to that of conventional positive photoresists based on novolac resins. © 1995 John Wiley & Sons, Inc.
Synthesis and characterization of poly[2,5‐bis(triethoxy)‐1,4‐phenylene vinylene]
Authors: Garay Raul O. , Mayer Bernd , Karasz Frank E. , Lenz Robert W.
Published: April 2003

The synthesis of a highly soluble, 2,5‐disubstituted poly(p‐phenylene vinylene) with pendant side chains containing ether groups was accomplished by a dehydrochlorination route. Specific interactions of the oxygen‐containing side chains with the solvent are presumably responsible for the high solubility of the polymer, especially in protogenic solvents. The polymer microstructure was characterized by 1H‐ and 13C‐NMR. The polymer showed solvatochromic properties when dissolved in a variety of solvents. The relatively high molecular weight (Mn = 17,000) permitted the fabrication of free‐standing films. The electrical conductivity of iodine‐doped films was approximately 2 × 10–2 S cm–1. © 1995 John Wiley & Sons, Inc.
Structure/Reactivity relationships for high‐performance polyamides: Kinetics of the reactions of N,N′‐dihexylphthalamides in the presence of added copper iodide and water
Authors: Broadbelt Linda J. , Klein Michael T. , Dean Barry D. , Andrews Stephen M.
Published: April 2003

An experimental study to determine the effect of copper(I) iodide and water on the rate and product distribution of aliphatic‐aromatic polyamide degradation was carried out by using N,N′‐dihexylterephthalamide (DHT) and N,N′‐dihexylisophthalamide (DHI) as models of the amide functionality. DHT was reacted in an inert argon atmosphere at 350°C in the presence of CuI added in amounts ranging from 0–5% by weight. The rate of disappearance of DHT was enhanced by a factor of three with the addition of 0.5% CuI. Increases to 5 wt % did not change the disappearance kinetics further. Comparison of the behavior of DHT and DHI revealed that changes in rate of disappearance and product yields were dependent on the relative positions of the amide substituents. Reaction of DHI was enhanced more significantly at a given CuI loading. The rate of disappearance of DHI and DHT and the selectivity to N‐hexylbenzamide increased with the addition of water in loadings ranging from 0.148M to 0.193M. The reactivity of DHI was more greatly enhanced at a given water loading. These differences were attributed to electronic effects, as evaluated by differences in atomic partial charges, and physical effects. © 1995 John Wiley & Sons, Inc.
Characterization of vanadium‐based olefin polymerization catalyst precursors by solid‐state 51v‐nmr
Authors: McFaddin Douglas , Reinking Mark
Published: April 2003

Several VOCL3‐based ethylene polymerization catalyst precursors were prepared on silica and studied by solid‐state 51V‐NMR. The structure of the vanadium species in these samples, as determined by 51V‐NMR, did not have any significant effect on the resultant polyethylene MI or MWD. This result is significant since conventional wisdom says the attachment of the transition metal to the silica plays a key role in polymer properties. VOCl3 reacted with hexamethyldisilazane‐treated silica and with 250°C dried silica results in double attachment of the vanadium to the silica, yet the catalysts which formed had different reactivities and produced polyethylene with different HLMIs. On the other hand, VOCl3 reacted with 600°C dried silica results in single attachment of the vanadium to the silica, yet this catalyst had a similar reactivity and produced polymer properties similar to the doubly attached vanadium on 250°C dried silica. Two theories are offered to explain the lack of correlation between catalyst precursor structure and catalyst performance. © 1995 John Wiley & Sons, Inc.
Synthesis and characterization of anionic graft copolymers containing poly(ethylene oxide) grafts
Authors: Dérand Helene , Wesslén Bengt
Published: April 2003

Anionic graft copolymers were synthesized through grafting of poly(ethylene glycol) monomethyl ether (MPEG) onto terpolymers containing succicinic anhydride groups. The backbone polymers were prepared through radical terpolymerization of maleic anhydride, styrene, and one of the following monomers: methyl methacrylate, ethylhexyl methacrylate, and diethyl fumarate. MPEG of different molecular weights were grafted onto the backbone through reactions with the cyclic anhydride groups. In this reaction one carboxylic acid group is formed together with each ester bond. The molecular weights of MPEG were found to influence the rate of the grafting reaction and the final degree of conversion. The graft copolymers were characterized by IR, GPC, and 1H‐NMR. Thermal properties were examined by DSC. Graft copolymers containing 50% w/w of MPEG 2000 grafts were found to be almost completely amorphous, presumably because of crosslinking, and hydrogen bonding between carboxylic acid groups in the backbone and the ether oxygens in MPEG grafts. © 1995 John Wiley & Sons, Inc.
Synthesis and photopolymerization of monomers bearing isopropenylphenoxy groups
Authors: Crivello J. V. , Lai Y.‐L.
Published: April 2003

The synthesis of a series of monomers containing isopropenylphenoxy groups was carried out. On irradiation with UV light in the presence of onium salt photoacid generators, these monomers undergo a chain extension reaction consisting of a dimerization followed by a Friedel‐Crafts ring closure which results in the formation of polymers with indane groups in the backbone. Aryl imide‐containing monomers bearing isopropenylphenoxy groups were also shown to undergo facile photoinduced cationic polymerization. The resulting polymers displayed excellent thermal stability. © 1995 John Wiley & Sons, Inc.
Isotactic poly(acrylonitrile) via ultraviolet irradiation of acrylonitrile‐urea canal complex
Authors: Minagawa Masatomo , Nouchi Kentaro , Tozuka Masahiro , Chujo Riichiro , Yoshii Fumio
Published: April 2003

Isotactic poly(acrylonitrile) (PAN) has been prepared by means of a conventional ultraviolet (UV) irradiation apparatus without γ‐ray sources; an acrylonitrile‐urea canal complex was directly formed at the surface of the UV (Hg) emission tube at low temperatures (∼ −78°C). When the complex was UV‐irradiated at this temperature, a stereoregular polymer was formed in the canal. The 13C‐NMR analyses indicate that (1) these PAN are rich in isotactic configuration, (2) the extent of the isotactic triad is in the range of 56−71%, and (3) the penultimate unit effect, 4 (mm) (rr)/(mr)2, is linearly correlated with the ultimate unit effect, (mm)/(rr). From the plots of log{4(mm)(rr)/(mr)2} vs log{(mm)/(rr)}, the anomaly in the polymerization of AN is discussed. The molecular characteristics of the UV canal PAN such as molecular weight, etc., were briefly noted. © 1995 John Wiley & Sons, Inc.
Synthesis and characterization of glycine copolymers of nylons 6 and 12
Authors: Franco Lourdes , Xenopoulos Alexander , Subirana Juan A. , Puiggali Jordi
Published: April 2003

Copolymers of glycine and 6‐aminohexanoic or 12‐aminododecanoic acid within a range of molar compositions from 80/20 to 5/95 were prepared by solution polycondensation of the adequate proportion of the respective pentachlorophenyl ester hydrobromides. Despite their random composition, the copolymers obtained were found to be highly crystalline. Intrinsic viscosities of 2/6 and 2/12 copolyamides were similar and rather low (Mn, ca. 3000‐5000). Thermal post‐polycondensation allowed to increase the molecular weight of 2/12 copolyamides, so that fibers could be prepared. The composition and sequence distributions were evaluated by means of 1H‐ and 13C‐NMR spectroscopies. Copolyamides were also characterized in terms of thermal properties. Melting and glass transition temperatures are reported. Crystallinity was evaluated from heats of fusion. Crystalline structure was examined by infrared spectroscopy and wide‐angle x‐ray diffraction. The presence of structures related to the polyglycine I and to α/γ‐nylons was confirmed depending on the molar composition. Highly oriented fibers with good tensile properties were obtained from the nylon 2/12 (10 : 90) copolymer. © 1995 John Wiley & Sons, Inc.
Amine/anhydride reaction versus amide/anhydride reaction in polyamide/anhydride carriers
Authors: Maréchal Philippe , Coppens Gaétane , Legras Roger , Dekoninck Jean‐Marc
Published: April 2003

Polyamide 6 (PA6) and poly(metaxylene adipamide) (PAmXD6) were blended in a batch mixer with anhydrides such as phthalic anhydride, n‐octadecyl succinic anhydride, and anhydride‐grafted ethylene propylene rubber. The melt viscosity, the solution viscosity, and chain end concentration were studied during the mixing. PA was first mixed 5 min to get an homogeneous melt prior to the anhydride addition. The introduction of the anhydride to the molten polyamide resulted in large decreases of melt and solution viscosities and of amine chain end concentrations. The anhydride units react with amine chain ends to form imide groups. The resulting low amine chain end concentration causes hydrolysis reaction to maintain the condensation equilibrium. As a consequence an increased carboxylic chain end concentration is observed. The imide concentration was studied by IR. It was shown that when most of the amine chain ends are consumed, the remaining anhydride reacts with amino groups formed by polyamide hydrolysis. © 1995 John Wiley & Sons, Inc.
Synthesis of a tetra(maleimide) as intermediate compound in a linear Diels–Alder polyaddition of bismaleimides with bis(2‐pyrone)s
Authors: Alhakimi Gamil , Klemm Elisabeth
Published: April 2003

The tetrafunctional products 3 and 6 were synthesized via Diels‐Alder reaction of bis(2‐pyrone) with bismaleimides in mol ratio 1:7. The chemical structure of these products was determined by 1H‐NMR spectroscopy; the high degree of purity was confirmed by means of elemental analysis. The cyclization of the tetraimide 3 with 2 mol monopyrone 7 to the bicycle 8 was carried out. © 1995 John Wiley & Sons, Inc.
Synthesis of branched copolysilanes from trichlorosilanes
Authors: Sasaki Manabu , Matyjaszewski Krzysztof
Published: April 2003

Soluble polymers and copolymers have been prepared from monosubstituted trichlorosilanes via thermal reductive coupling with sodium in toluene. Phenyltrichlorosilane has been copolymerized with methylphenyl dichlorosilane, with n‐hexyltrichlorosilane, with tetrachlorosilane and with tetrakis(chlorodimethylsilyl)silane. n‐Hexyltrichlorosilane has been copolymerized with methylphenyldichlorosilane, with phenyltrichlorosilane and with silicon tetrachloride. Soluble polymers and copolymers with molecular weight in the range ≈ 2,000 to ≈ 106 have been obtained. The absorption and emission spectra of the resulting polymers are strongly affected by the presence of trisilyl‐ and tetrasilylsubstituted silicon atoms. © 1995 John Wiley & Sons, Inc.
Synthesis and characterization of aromatic amine functional semicrystalline aryl ether ketone macromers
Authors: Bourgeois Y. , Devaux J. , Legras R. , Charlier Y. , Hedrick J. L.
Published: April 2003

From earlier experiments it was observed that the reactions of aryl fluoride functional aryl ether ketone oligomers (PEK) with m‐aminophenol lead to poor levels of amine incorporation because of side‐reactions. In this article, a method is presented to protect the m‐aminophenol by converting it into a triarylimine group. This protected m‐aminophenol was used together with 4‐fluoro,4′‐hydroxybenzophenone in a typical poly(aryl ether) synthesis. PEKs of different molecular weights were synthesized with number average molecular weights \documentclass{article}\pagestyle{empty}\begin{document}$\overline {M}_n$\end{document}) of 2600, 4500, and 5400 g/mol. The deprotection of the triarylimine chain end was carried out by an acid treatment to afford a monofunctional aromatic amine end group, amenable towards copolymerization. © 1995 John Wiley & Sons, Inc.
Characterization of PET surface modification with CF4‐CH4 (CF4/CH4 > 5) RF plasma by XPS and contact angle techniques
Authors: Wei Xiang , Xiaodong Chen , Jianqi Wang
Published: April 2003

RF plasma of CF4/CH4 (> 5) was subject to further investigation by XPS and the contact angle method. An attempt has been made aiming at distinguishing the mechanistic aspects of PET surfaces exposed to CF4/CH4 plasmas. It follows that in addition to region 3 (83.3–0.0% CF4) there are two regions within the range of 83.3–100% CF4. Region 1 (100–96.8% CF4) is a region of etching/fluorination predominated and region 2 (96.8–83.3% CF4) is polymerization predominated. For a complete description of the entire process the fluorination (or grafting, implantation) should be incorporated into the CAP model. The homogeneity along depth of the surface layers can be intuitively observed with the help of the angle‐dependent XPS, which turns out to be of great importance in comparison with the sampling depth of the contact angle technique under various experimental conditions. © 1995 John Wiley & Sons, Inc.
Molecular characterization of maleic anhydride‐functionalized polypropylene
Authors: De Roover B. , Sclavons M. , Carlier V. , Devaux J. , Legras R. , Momtaz A.
Published: April 2003

This work deals with the molecular characterization of maleic anhydride melt‐functionalized polypropylene (PP‐g‐MA). The functionalization mechanism, the nature, the concentration, and the location of grafted anhydride species onto the polypropylene chain are discussed. The polypropylene functionalization was performed using a pre‐heated Brabender Plastograph (190°C, 4 min of mixing time). Several concentrations of maleic anhydride and organic peroxide were used for this study. In those experimental conditions, the organic peroxide undergoes an homolytic rupture and carries out a polypropylene tertiary hydrogen abstraction. The resulting macroradical undergoes a β‐scission leading to a radical chain end which reacts with maleic anhydride. When a termination reaction occurs at this first step a succinic type anhydride chain end is obtained. However, oligomerization of maleic anhydride is found to occur more frequently leading to poly (maleic anhydride) chain end. Concentration of both anhydride types and minimal length of the grafted poly (maleic anhydride) were determined. A fraction of maleic anhydride does not react with polypropylene or homopolymerize leading to nongrafted poly (maleic anhydride). © 1995 John Wiley & Sons, Inc.
Reactivity of polymeric amines toward peptide bond formation‐aminolysis of poly(aminoacrylamide)s by N‐benzoylglycine 4‐nitrophenyl ester
Authors: Chandy Mathew C. , Pillai V. N. Rajasekharan
Published: April 2003

Polymeric amines derived from copolymers of acrylamide (AA) cross‐linked with bifunctional crosslinking agents of varying polarity and hydrophilicity were studied for their reactivity in the aminolysis of N‐benzoylglycine 4‐nitrophenyl ester. The reaction did not follow simple kinetics. © 1995 John Wiley & Sons, Inc.
Investigations on monotropic liquid crystalline polyurethanes based on biphenylol
Authors: Haridas K. R. , Radhakrishnan Ganga
Published: April 2003

2,2′‐Azobis‐[2‐cyano‐(4‐ethylphenol)] (ABCP) was prepared from parahydroxyacetophenone, using hydrazine sulfate and sodium cyanide. Biphenylol ester of ABCP, 2,2′‐azobis‐[2‐p‐biphenyloxy‐(4‐ethylphenol)] (BECP) was synthesized via the acid route. Combined liquid crystalline polyurethanes (CLCPUs) were synthesized from 1,6‐diisocyanatohexane (HDI) and BECP in dimethylformamide (DMF) at 110°C under nitrogen atmosphere. The effect of partial replacement of BECP by 4,4′‐dihydroxy biphenyl (DHBP) on liquid crystalline (LC) properties was studied. The polymers were characterized by proton and 13C NMR, FTIR, and UV spectroscopy. Elemental analysis were done for determining the percentage content of C, H, and N and the molecular weights of the polymers were determined by gel permeation chromatography (GPC). Thermogravimetric investigations (TGA) of the polyurethanes (PUs) were performed to study the decomposition. The LC nature of the PUs was confirmed by differential scanning calorimetry (DSC) and X‐ray diffraction (XRD). Cross‐polarized optical microscopy studies demonstrated the existence of two distinct crystalline morphologies, a spherulitic morphology with high mole ratio of DHBP and a thread‐like crystalline morphology with that of BECP. All the PUs synthesized showed a LC nature with a wide temperature range. Partial replacement of BECP by DHBP changed the mesomorphic nature, transition temperature, and temperature range of the mesophase. © 1995 John Wiley & Sons, Inc.
“Close loop” mechanistic schemes for hydrocarbon polymer oxidation
Authors: Audouin L. , Gueguen V. , Tcharkhtchi A. , Verdu J.
Published: April 2003

Mechanistic schemes of radical oxidation of hydrocarbon polymers in which initiation is only due to unimolecular or bimolecular hydroperoxide decomposition have been studied. The results of their kinetic analysis have been compared with literature data relative to the thermal oxidation of polypropylene in solid state (60‐160°C). These data are in remarkably good agreement with the “unimolecular” scheme whose main characteristics are: (1) the quasi‐independence of the kinetic behavior with initial conditions (for low initial content of thermolabile structures), and (2) the fact that an arbitrarily defined induction period depends only on the rate constant of unimolecular hydroperoxide decomposition. © 1995 John Wiley & Sons, Inc.
Photoinitiators with functional groups. III. Water‐soluble photoinitiators containing carbohydrate residues
Authors: Knaus S. , Gruber H. F.
Published: April 2003

A series of new water‐soluble photoinitiators (PIs) for UV curing of water‐borne systems was synthesized by covalent bonding of carbohydrate residues such as D‐glucose, sucrose, maltose, 1‐amino‐D‐sorbitol and D‐gluconicacid‐δ‐lactone to the commercially available PI 2‐hydroxy‐1‐[4‐(2‐hydroxy‐ethoxy)phenyl]‐2‐methylpropan‐1‐one (Darocur 2959) (1). In addition, new functional derivatives of 1 containing tosyl‐ or chloride residues as well as primary or secondary amino groups were prepared. Preliminary photocalorimetric tests of the activity demonstrated excellent efficiencies of the PIs in a commercial water‐based acrylate formulation exceeding the photoactivity of the reference PI (1) substantially. © 1995 John Wiley & Sons, Inc.
Synthesis and reaction of polymers bearing 5‐membered cyclic dithiocarbonate group
Authors: Kihara Nobuhiro , Tochigi Hidefumi , Endo Takeshi
Published: April 2003

5‐(Methacryloyloxy)methyl‐1,3‐oxathiolane‐2‐thione (3) was synthesized from glycidyl methacrylate (GMA) and carbon disulfide in the presence of lithium bromide in 93% yield. The radical polymerization of 3 in DMSO initiated by AIBN at 60°C afforded corresponding polymethacrylate 4 quantitatively. Copolymerization of 3 with MMA was also carried out. 5‐Phenoxymethyl‐1,3‐oxathiolane‐2‐thione (6), model dithiocarbonate, reacts with benzylamine at room temperature to afford O‐(1‐mercapto‐3‐phenoxy‐2‐propyl)N‐benzyl‐thiocarbamate (7) and 1,1′‐dithiobis[3‐phenoxy‐2‐(benzylaminothiocarbonyloxy)‐propane] (8) in 89% and 7% yield, respectively. Polymer 4 reacted with butylamine or dipropylamine to afford a corresponding polymethacrylate bearing thiol group, which immediately turned to insoluble gel by facile auto‐oxidation of the thiol group. © 1995 John Wiley & Sons, Inc.
A possible route to the controlled synthesis of polymethyloxirane oligomers using bimetallic μ‐oxoalkoxides
Authors: Taquet A. , Jérôme R. , Teyssié Ph. , Masy J. P. , Goethals E.
Published: April 2003

Soluble μ‐oxo‐bimetallic trinuclear alkoxides are known to be very effective catalysts for the ring‐opening polymerization of oxiranes. In the particular case of methyloxirane, oligomers are formed in addition to high molecular weight polyethers. An alkoxide‐alcohol exchange reaction has proved to be an efficient way to form oligomers preferentially, when the monomer‐alcohol molar ratio is small. Upon increasing this ratio, formation of high MW chains occurs increasingly. The use of Ti instead of Al in Al, Zn μ‐oxo‐n‐butoxide in the presence for phenoxyethanol as a co‐initiator inhibits formation of exceedingly long polyether chains and the chain length is basically controlled by the monomer to all potential initiating species molar ratio until MW of ca. 6000. Substitution of phenoxyethanol by polypropylene glycol has led to oligomers of a monomodal MW distribution and a MW of 13,000. This study has highlighted that conditions unfavorable to coordination of the polyether chains onto the catalyst improve the control of the oligomer formation. © 1995 John Wiley & Sons, Inc.
Fluorinated NLO polymers with improved optical transparency in the near infrared
Authors: McCulloch Iain , Yoon Hyun
Published: April 2003

The absorption from vibrational overtones in the near infrared and specifically at 1.55 μm, is a major contribution to the optical loss of NLO polymer waveguides. In an effort to reduce this value, the specific molecular vibrations responsible, which had previously been predicted by theoretical means, were identified by solvent spectra analysis. A scheme was proposed to reduce the intrinsic absorption through synthetic modification of the polymer by replacement of appropriate aliphatic CH bonds with CF bonds. Specific bonds were chosen for replacement based on a consideration of both contribution to intrinsic absorption as well as ease of synthetic modification. The target polymer was synthesized and its absorption measured by a solution technique. A reduction in optical loss at 1.55 µ from 0.75 to 0.35 dB cm−1 was achieved. © 1995 John Wiley & Sons, Inc.
Solvent effects on ester alcoholysis at functionalized polyethylene surfaces
Authors: Bergbreiter David E. , Aguilar Gaston A.
Published: April 2003

The effects of solvent on the accessibility and reactivity of an ester‐bound fluorophore at a functionalized polyethylene‐solvent interface have been studied. Fluorophore‐labeled polyethylene surfaces were prepared by blending together a small amount of a pyrene esterterminated ethylene oligomer and a host linear low density polyethylene in solution. Films cast from such solutions were then studied by fluorescence spectroscopy to show that a significant number of the entrapped pyrene groups were at the polyethylene‐solvent interface and capable of reaction with soluble reagents. Subsequently, transesterification of these ester‐bound pyrenes using various sodium alkoxides in alcohol, alcohol‐toluene, or alcohol‐tetrahydrofuran solvent mixtures was studied by fluorescence and UV‐visible spectroscopic analysis of the supernatant. The extent of alcoholysis of such esters was found to be significantly affected by the solvent chosen and by the structure of the alcohol. © 1995 John Wiley & Sons, Inc.
Graft copolymers having hydrophobic backbone and hydrophilic branches. X. Preparation and properties of water‐dispersible polyanionic microspheres having poly(methacrylic acid) branches on their surfaces
Authors: Riza Medyan , Tokura Seiichi , Iwasaki Minoru , Yashima Eiji , Kishida Akio , Akashi Mitsuru
Published: April 2003

The free radical copolymerization of poly(t‐butyl methacrylate) (PBMA) macromonomer with styrene in ethanol give monodispersed microspheres with 0.8‐1.6 μm diameter. The resulting microspheres were treated with HCl solution to convert into anionic microspheres having poly(methacrylic acid) chains. ESCA analysis of the microsphere surface suggested that PBMA chains were favorably located on the surface of the microspheres. The particle size of the microspheres decreased with increasing molecular weight and concentration of the macromonomer. Water dispersibilities of the microspheres were evaluated by measuring the relative turbidity of the suspension of microspheres as a function of pH. The results show that they were strongly dependent on pH. © 1995 John Wiley & Sons, Inc.
Synthesis and polymerization of N‐[N′‐(α‐methylbenzyl)aminocarbonyl‐n‐alkyl]maleimide
Authors: Oishi Tsutomu , Kagawa Kensoh , Fujimoto Minoru
Published: April 2003

Two types of optically active N‐[N′‐(α‐methylbenzyl)amino/carbonyl‐n‐alkyl]maleimides (MBAC) were synthesized from maleic anhydride, 6‐amino‐n‐caproic acid (or 12‐amino‐n‐dodecanoic acid), and (R)‐(+)‐α‐methylbenzylamine. Radical homopolymerizations of MBAC were performed in several solvents at 60 and 110°C for 24 h to give optically active polymers. Radical copolymerizations of MBAC were performed with styrene (ST) and methyl methacrylate (MMA) in dioxane at 60°C. The monomer reactivity ratios and the Alfrey‐Price Q‐e values were determined. Chiroptical properties of the polymers and copolymers were investigated. © 1995 John Wiley & Sons, Inc.
Radical polymerization of vinyl monomer having diacylurea moiety
Authors: Kanamaru Masami , Takata Toshikazu , Endo Takeshi
Published: April 2003

N‐acryloyl‐N′‐benzoylurea (1) was prepared and its radical homopolymerization and copolymerization with styrene were carried out. 1 was synthesized yield by the reaction of benzoylisocyanate and acrylamide in tetrahydrofuran in 78%. Radical polymerization of 1 was carried out at 60 or 80°C in DMF (0.1‐2.5M) for 5 h in a sealed tube using AIBN (3 mol %) or BPO (3 mol %) as initiators to obtain poly(N′‐acryloyl‐N′‐benzoylurea) (2) as a methanol‐insoluble part in good yield (75–82%) independent of concentration. Number‐average molecular weights of 2 were 2700–91,900. Furthermore, copolymerization of 1 with styrene was carried out in various feed ratios to confirm the alternating character in the copolymerization (r1r2 = 0.21) and Q, e values of 1 were evaluated as 0.52, 1.16, respectively. © 1995 John Wiley & Sons, Inc.
Gamma‐oxidation of linear low‐density polyethylene: The dose–rate effect of irradiation on chemical and physical modifications
Authors: Tidjani Adams , Watanabe Yasushi
Published: April 2003

γ‐Oxidation of linear low‐density polyethylene based on hexene and butene was investigated. Irradiation was performed at different dose rates in air (from 2 rad/s to 100 rad/s). Degraded samples were analyzed with IR combined with NO and SF4 derivatizations. Our results showed that the lower the dose rate, the higher the degree of oxidation in terms of γ‐product formation. Ketone species appeared to be the dominant γ‐products. The G values of γ‐product formation were very dependent on the dose rate of initiation. Comparison of the G value ratio of different γ‐products revealed stoechiometry differences. The complex appearance and disappearance of unsaturations was tentatively explained. The modifications of elongation at break induced by γ‐irradiation were monitored by molecular changes in weight. This was not conclusive because changes in elongation at break are inconsistent with changes in Mw/Mn. © 1995 John Wiley & Sons, Inc.
Synthesis and polymerization of 1‐(2,4,6‐tricyanophenylthio)‐3‐[3,5‐bis(n,n‐dimethylamino)phenoxy]‐2‐propyl methacrylate; polymer effect on intramolecular charge–transfer interaction
Authors: Itoh Takahito , Noki Ryuichi , Simosato Shinji , Magara Isao , Iwatsuki Shouji
Published: April 2003

1‐[3,5‐Bis(N,N‐dimethylamino)phenoxy]‐ω‐(2,4,6‐tricyanophenylthio)alkanes (1a–c), where an electron‐accepting 2,4,6‐tricyanophenylthio group and an electron‐donating 3,5‐bis(N,N‐dimethylamino)phenoxy one are linked with a spacer such as ethylene, trimethylene, and tetramethylene, were prepared in order to examine an effect of the spacer chain length on intramolecular charge–transfer interaction between the 2,4,6‐tricyanophenylthio and 3,5‐bis(N,N‐dimethylamino)phenoxy groups. From the UV‐vis spectra measurements of 1a–c, 1‐[3,5‐bis(N,N‐dimethylamino)phenoxy]‐3‐(2,4,6‐tricyanophenylthio)Propane (1b) carrying the trimethylene chain as a spacer was found to have the strongest intramolecular charge–transfer interaction. A new methacrylate‐type monomer carrying the 1b unit as a side chain, 1‐(2,4,6‐tricyanophenylthio)‐3‐[3,5‐bis(N,N‐dimethylamino)phenoxy]‐2‐propyl methacrylate (2), was prepared successfully in 9.2% total yield in seven steps. The monomer 2 homopolymerized in benzene, tetrahydrofuran, acetone, and dimethyl sulfoxide in the presence of 2,2′‐azobis(isobutyronitrile) at 60°C to give polymers [poly(2)] with molecular weights of 6,000 to 98,000. An intramolecular charge–transfer interaction in the poly(2) was found to be larger than that in the monomer 2 and to increase with an increase in the degree of polymerization of the poly(2), suggesting that there is an existence of polymer effect other than the polymer effect due to the high local concentration of the donor‐acceptor pair. © 1995 John Wiley & Sons, Inc.
Synthesis and properties of polyimides derived from 1,6‐bis(4‐aminophenoxy)naphthalene and aromatic tetracarboxylic dianhydrides
Authors: Yang Chin‐Ping , Hsiao Sheng‐Huei , Jang Chin‐Cheng
Published: April 2003

1,6‐Bis(4‐aminophenoxy)naphthalene (I) was used as a monomer with various aromatic tetracarboxylic dianhydrides to synthesize polyimides via a conventional two‐stage procedure that included ring‐opening polyaddition in a polar solvent such as N,N‐dimethylacetamide (DMAc) to give poly(amic acid)s, followed by thermal cyclodehydration to polyimides. The diamine (I) was prepared through the nucleophilic displacement of 1,6‐dihydroxynaphthal‐ene with p‐chloronitrobenzene in the presence of K2CO3, followed by catalytic reduction. Depending on the dianhydrides used, the poly(amic acid)s obtained had inherent viscosities of 0.73–2.31 dL/g. All the poly(amic acid)s could be solution cast and thermally converted into transparent, flexible, and tough polyimide films. The polyimide films had a tensile modulus range of 1.53–1.84 GPa, a tensile strength range of 95–126 MPa, and an elongation range at break of 9–16%. The polyimide derived from 4,4′‐sulfonyldiphthalic anhydride (SDPA) had a better solubility than the other polyimides. These polyimides had glass transition temperatures between 248–286°C (DSC). Thermogravimetric analyses established that these polymers were fairly stable up to 500°C, and the 10% weight loss temperatures were recorded in the range of 549–595°C in nitrogen and 539–590°C in air atmosphere. © 1995 John Wiley & Sons, Inc.
Macromolecular synthesis from saccharic lactones. Polyaddition of D‐glucaro‐ and D‐mannaro‐ 1,4:6, 3‐dilactones with diisocyanates and hydrolyzability of the resulting polyurethanes having dilactone rings in the main chains
Authors: Hashimoto Kazuhiko , Wibullcksanakul Sirinat , Okada Masahiko
Published: April 2003

Polyaddition of saccharic acid dilactones prepared from D‐glucose and D‐mannitol, D‐glu‐caro‐, and D‐mannaro‐1,4:6,3‐dilactones (1 and 2, respectively), with hexamethylene di‐isocyanate (3a) and methyl (S)‐2,6‐diisocyanatocaproate (3b) was carried out by using dibutyltin dilaurate as a catalyst at 50, 25, and 0°C to give polyurethanes (4 and 5) having dilactone moieties in the main chains. The resulting polymers were found to decompose easily in phosphate buffers under neutral or slightly basic conditions (pH 7 or 8). Therefore, the polyurethanes may be used as novel degradable polymeric materials. © 1995 John Wiley & Sons, Inc.
Polymerization behaviour of 2,5‐dimethylene‐ 2,5‐dihydrofuran
Authors: Itoh Takahito , Katoh Ichiro , Satoh Toshiya , Iwatsuki Shouji
Published: April 2003

Spontaneous homopolymerization of 2,5‐dimethylene‐2,5‐dihydrofuran (DDF) was studied. The polymerization rates in two different initial monomer concentrations of DDF were analyzed with the first‐order and second‐order kinetics, and the homopolymerization of DDF was found to obey the first‐order kinetics. The Arrhenius plot of the apparent rate constants at 30, 40, 50, and 60° gave an overall activation energy of 68.0 kJ/mol for the polymerization of DDF. From the comparison of the apparent rate constants at –78° and the time (the so‐called half‐life time) to decrease in half the monomer concentration for DDF with the corresponding values for p‐xylylene (QM), DDF was found to be a less reactive monomer than QM. The copolymerizations of DDF with vinyl monomers such as acrylonitrile (AN), α‐chloroacrylonitrile (CIAN), diethyl fumarate (DEF), and fumaronitrile (FN) were carried out in chloroform at 50° in the presence of AIBN to obtain the monomer reactivity ratios r1(DDF) = 30.0 ± 3.0 and r2 (AN) = 0 for the DDF‐AN system, r1 (DDF) = 1.55 ± 0.2 and r2(CIAN) = 0 for the DDF‐CIAN system, r1(DDF) = 3.88 ± 0.2 and r2(DEF) = 0 for the DDF‐DEF system, and r1(DDF) = 2.41 ± 0.1 and r2 (FN) = 0 for the DDF‐FN system, respectively. As the monomer reactivity ratios of r2 for all systems were zero, Q and e values of DDF were calculated from the combination of two r1 (DDF) values of any two copolymerization systems to be the 7.64 to 6.63 ×1021 range for Q and the –0.70 to –6.31 range for e, indicating that DDF is a highly conjugative and electron‐donating monomer. © 1995 John Wiley & Sons, Inc.
Synthesis and property of soluble poly(1,1′‐dialkyl‐3,3′‐ferrocenylenevinylene)s via titanium‐induced dicarbonyl‐coupling reaction of 1,1′‐dialkylferrocene‐3,3′‐dicarbaldehydes
Authors: Itoh Takahito , Saitoh Hiroki , Iwatsuki Shouji
Published: April 2003

1,1′‐Dialkylferrocene‐3,3′‐dicarbaldehydes (1a–c) with long alkyl chains such as ethyl, hexyl, and dodecyl groups were prepared in 13–25% yield via three‐step reactions. The titanium‐induced dicarbonyl‐coupling reaction of 1a–c gave poly(1,1′‐dialkyl‐3,3′‐ferrocenylenevi‐nylene)s (2a–c) in quantitative yields, which were the molecular weights of 3000–10,000 and highly soluble in chloroform, benzene, and hexane. The electrical conductivity and the third‐order nonlinear optical susceptibility for poly(1,1′‐dihexyl‐3,3′‐ferrocenylenevinylene) (2b) were estimated to be 1 × 10−2 S/cm on doping with iodine and 1–4 × 10−12 esu at a wavelength of 1–2.4 μm, respectively. © 1995 John Wiley & Sons, Inc.
Control of surfactant level in starve‐fed emulsion polymerization. I. Sulfate‐containing oligomers: Preparation and application as surfactant in emulsion polymerization
Authors: Wang Zhiyu , Paine Anthony J. , Rudin Alfred
Published: April 2003

It is well known that the amount of surfactant must be carefully controlled during starve‐fed emulsion polymerization processes. Too little surfactant leads to emulsion instability and coagulation, while too much surfactant leads to secondary particle formation. Although these relationships are qualitatively understood in the art, there is little quantitative basis to guide the synthetic chemist, especially in multistep starve‐fed emulsion polymerization processes to make larger supermicron particles. We have developed a method, which will be described in a companion article, to control the surfactant level by monitoring the surface tension during polymerization. In order to quantitatively predict how much surfactant to add at any given time, one needs to know in advance the adsorption characteristics of the soap. Further complicating the matter is the formation of “in situ” or oligomeric surfactant during polymerization with aqueous initiators such as ammonium persulfate.

This work demonstrates how to prepare surface‐active oligomers and how to make latex particles using them as surfactant. First, we established the mass balance for the initiator‐derived sulfate groups in seed latexes by conductometric, potentiometric, and iodometric titrations. Based on the characterization of seed latexes, a method for determining the effective sulfate concentration has been developed. When surface‐active oligomers were used as the only surfactant, we obtained a series of monodisperse, supermicron copolymer latex particles with diameters up to 3.22 μm. This is a similar result to that obtained with a commercially made anionic surfactant. © 1995 John Wiley & Sons, Inc.
Studies on the polymerization mechanism of 3‐nitratomethyl‐3′‐methyloxetane and 3‐azidomethyl‐3′‐methyloxetane and the synthesis of their respective triblock copolymers with tetrahydrofuran
Authors: Liu Ying‐Ling , Hsiue Ging‐Ho , Chiu Yie‐Shun
Published: April 2003

Novel energetic oxetane derivatives, 3‐nitratomethyl‐3′‐methyloxetane (NMMO) and 3‐azidomethyl‐3′‐methyloxetane (AMMO), were used as monomers in a triflic anhydride [(CF3SO2)2O] initiating polymerization system. The “living cationic” characteristics of the polymerization were investigated and confirmed via a 19F NMR technique. This living polymerization system was, thus, utilized in the synthesis of well‐defined block copolymers. Novel polymers of the A—B—A— type with various molecular weights (M̄w = 14320–40660) and low polydispersity indexes (PDI = 1.11–1.29) were obtained. Two glass transition temperatures (Tg) near the respective Tgs of the homopolymers were found in the DSC thermograms of the block copolymers. The THF/AMMO copolymers were shown to possess higher thermal stability compared to THF/NMMO copolymers from thermogravimetric analysis (TGA). © 1995 John Wiley & Sons, Inc.
Preparation and properties of polyurethane networks based on α,ω‐difunctional poly(hexafluoropropylene oxide)
Authors: Proudmore Martin , Ding Ji‐Feng , Mobbs Richard H. , Yeates Stephen G. , Price Colin , Booth Colin
Published: April 2003

Poly(hexafluoropropylene oxide), poly(HFPO), networks were prepared from functional polymers by end linking via urethane groups. The prepolymers were characterized by NMR spectroscopy and GPC. The networks were characterized by determination of the number of network chains from the shear modulus, and were snown to contain both trifunctional crosslinks and difunctional links. The properties of the networks were investigated by a range of techniques. Compared with fully‐fluorinated networks formed via triazine cross‐links, investigated previously, the urethane‐linked networks were more readily prepared but were poorer elastomers, were less thermally stable, and were less resistant to swelling by common polar solvents. © 1995 John Wiley & Sons, Inc.
Synthesis and properties of polyimides from 4,4′‐binaphthyl‐1,1′,8,8′‐tetracarboxylic dianhydride
Authors: Gao Jian Ping , Wang Zhi Yuan
Published: April 2003

4,4′‐Binaphthyl‐1,1′,8,8′‐tetracarboxylic dianhydride was synthesized from 4‐chloro‐1,8‐naphthalic anhydride and polymerized with aromatic and pliphatic diamines in m‐cresol or N‐methyl‐2‐pyrrolidinone (NMP). The polyimides, except for two derived from p‐phenylenediamine and hydrazine, are soluble in 1,1,2,2‐tetrachloroethane and NMP. Their intrinsic viscosities ranged from 0.36 to 2.20 dL/g. The polymers showed excellent thermal and thermooxidative stabilities and displayed weak glass transition temperatures. Young's moduli of some polymer films were in the range of 2.5 and 5.4 GPa at 30°C. The aliphatic polyimides exhibited a stronger fluorescence than the aromatic polyimides. © 1995 John Wiley & Sons, Inc.
Solvation effect in thermal decomposition of 2,2′‐azoisobutyronitrile
Authors: Szafko J. , Feist W.
Published: April 2003

The solvation effect in the thermal decomposition of a radical initiator (AIBN) in monomer–solvent mixtures is discussed. Equations were derived which comprise the initiator decomposition constant as a function of the monomer mole fraction for chosen types of solvation. In addition, equations were deduced presenting the concentrations and partial relative decomposition rates for the solvated initiator species as a function of the monomer mole fraction. The equations obtained were compared to the experimental literature data and possible dependences of decomposition constants on monomer concentration were simulated for various solvated species. The simulated relationships were found to be straight lines, curves of saturated type (possessing a plateau), S‐shaped curves, and maximum or minimum curves. © 1995 John Wiley & Sons, Inc.
Radical polymerization of micelle‐forming monomers in water
Authors: Egorov Vladislav V.
Published: April 2003

Photo‐ and thermoinitiated radical polymerization of surface‐active monomers with various structures was investigated in solution and in micelles in water. The relationship between kinetics and the structure of monomer associates was represented in the form of a universal curve. A model and kinetic description of polymerization in spherical micelles of monomer was proposed. The problem of micelle fixation by polymerization was solved. © 1995 John Wiley & Sons, Inc.
Compartmentalized polymerization initiated by oil‐soluble initiators. Calculation of average number of radicals per particle
Authors: Mørk Preben C. , Ugelstad John , Aasen Jan Ole
Published: April 2003

Expressions for calculating the stationary state distribution of radicals in compartmentalized systems with a constant number of reaction loci containing an oil‐soluble initiator are given. Besides pairwise formation of radicals in the particles, desorption and reabsorption, water phase termination, solubility of the initiator in the aqueous phase, and the possibility of formation of a single radical species are taken into consideration. The calculation is based on a probabilistic analysis leading to a third‐order recurrence relation solved using confluent, hypergeometric Kummer functions. Some calculated curves illustrating the de‐pendence of the average number of radicals per particle on various relevant parameters are included. © 1995 John Wiley & Sons, Inc.