bluuebunny/crossref_metadata_2025 huggingface dataset:
Basic structure–property behavior of polyurethane cationomers
Authors: Lee Jong Cheol , Kim Byung Kyu
Published: April 2003

Polyurethane (PU) cationomers were synthesized from polytetramethylene adipate glycol (PTAd), isophorone diisocyanate (IPDI), and N‐methyl diethanolamine (MDEA) according to a prepolymer mixing process. Basic structure‐property behavior of the emulsion (obtained by adding water to the ionomer solution) and emulsion cast film was studied with regard to the molecular weight (Mn) of PTAd, MDEA content, degree of neutralization, and extender functionality. Particle size decreased asymptotically with increasing Mn of PTAd due to the increased chain flexibility, and with the degree of neutralization due to the increased hydrophilicity of the PU. Emulsion viscosity generally showed the opposite tendency with particle size dependence. The major transition temperature, corresponding to the glass transition (Tg) of phase mixed PU or hard segment‐rich phase of the PU monotonically increased with MDEA content, degree of neutralization, and with increasing extender functionality. However, with increasing Mn of PTAd, Tg first decreased (Mn = 1000) and then increased (Mn = 1500, 2000), due respectively to the increased hard fraction of phase mixed PU, and soft segment crystallization. Tensile strength increased and elongation at break decreased with MDEA content, degree of neutralization, and extender functionality. © 1994 John Wiley & Sons, Inc.
Polymeric networks by the cationic crosslinking reaction of poly(allenyl ether)s having oligo(oxyethylene) moieties in the side chain
Authors: Aggour Yassin A. , Tomita Ikuyoshi , Endo Takeshi
Published: April 2003

Cationic crosslinking reactions of poly(allenyl ether)s having oligo(oxyethylene) moieties prepared by the radical polymerization of the corresponding allenyl ethers were carried out under some varied reaction conditions. For instance, a crosslinked polymer was obtained in 82% yield by the treatment of poly(ethylene glycol methyl allenyl ether) (1a) with 1.2 mol% of BF3·OEt2 (2) under high concentration in dichloromethane (46 wt %). The gels obtained showed good swelling properties in water, alcohols, and polar organic solvents such as dichloromethane. In particular, the degrees of swelling of these gels in aqueous sodium chloride (1M) were quite similar to those in ion‐free water, indicating that these gels served as nonionic hydrogels. © 1994 John Wiley & Sons, Inc.
Polymeric phosphonium salts as a novel class of cationic biocides. IX. Effect of side‐chain length between main chain and active group on antibacterial activity
Authors: Kanazawa Akihiko , Ikeda Tomiki , Endo Takeshi
Published: April 2003

Polymeric phosphonium salts with different side‐chain length between the main chain and the active group, poly[4‐2‐tributyl‐phosphonioethyl)styrene chloride‐co‐4‐(2‐chloroethyl)styrene] and poly[4‐(3‐tributylphosphoniopropyl)styrene chloride‐co‐4‐(3‐chloropropyl)styrene], were prepared and their antibacterial activities against Staphylococcus aureus and Escherichia coli were examined by the viable cell counting method in sterile distilled water. The antibacterial activity was found to decrease as the side‐chain length increased. The most significant finding is a peculiar concentration dependence of the antibacterial activity, which demonstrated the presence of an optimal concentration. The observed specific effects of the side chain length and the concentration on the antibacterial activity seem to be ascribed to the state of aggregation of the polycationic biocides in aqueous solution. © 1994 John Wiley & Sons, Inc.
Kinetics of polyesterification: Effect of diol chain length
Authors: Uphade B. S. , Patil P. S. , Pandit S. B. , Rajan C. R. , Nadkarni V. M.
Published: April 2003

Kinetics of polyesterification of maleic anhydride with polyethylene glycol (PEG) of varying molecular weights have been evaluated. The investigations have been carried out by employing heating cycles comparable to those employed in industrial processes and under nonisothermal conditions. The rate of reaction was found to decrease with increase in the chain length of the polyether. The energy of activation was estimated as 26.91, 40.25, and 47.30 Kcal/mol for PEG of molecular weights 200, 300, and 400, respectively. © 1994 John Wiley & Sons, Inc.
Phase behavior of cyclic siloxane‐based liquid crystalline compounds
Authors: Gresham K. D. , McHugh C. M. , Bunning T. J. , Crane R. L. , Klei H. E. , Samulski E. T.
Published: April 2003

A series of 24 cyclic siloxane‐based liquid crystalline compounds was synthesized using conventional hydrosilation chemistry. Variables examined included ring size, spacer group length, and type and composition of pendant mesogeric groups. Both pentamethylhydro‐ and tetramethylhydrosiloxane rings were reacted with mesogens based on cholesterol, biphenyl, or equimolar mixtures of both. Four different length spacer groups containing terminal vinyl groups were used to attach the mesogens to the cyclic siloxane core. The thermotropic liquid crystalline phase behavior was studied using differential scanning calorimetry (DSC) and polarized optical microscopy (POM). A lengthening of spacer groups resulted in lower crystallization temperatures for the biphenyl‐based compounds and lower glass transition temperatures for the cholesterol‐ and mixed mesogen‐based compounds. The tetramethyl ring derivatives exhibited higher glass transition or crystallization temperatures than their pentamethyl counterparts. Biphenyl‐based compounds exhibited low temperature crystalline phases while the cholesterol‐based compounds exhibited low temperature glassy phases. © 1994 John Wiley & Sons, Inc.
Polymerization of N‐alkyl‐substituted itaconimides and N‐(alkyl‐substituted phenyl)itaconimides and characterization of the resulting polymers
Authors: Watanabe Hiroyuki , Matsumoto Akikazu , Otsu Takayuki
Published: April 2003

N‐alkyl‐substituted itaconimides (RII) and N‐(alkyl‐substituted phenyl)itaconimides (RPhII) with various alkyl substituents were prepared and polymerized in the presence of a radical or anionic initiator to give high molecular weight polymers in high yields. The effects of the alkyl substituents on the polymerization reactivities were investigated. It has been revealed that RII and RPhII have the highest polymerization reactivity compared with other itaconic and citraconic derivatives including dialkyl itaconates and citraconimides. The structure and some properties of poly(RII) and poly(RPhII) were examined. These polymers were found to have excellent thermal stability, better than poly (dialkyl itaconate)s. © 1994 John Wiley & Sons, Inc.
Radical polymerization of N‐substituted itaconamic esters and itaconamides
Authors: Watanabe Hiroyuki , Matsumoto Akikazu , Otsu Takayuki
Published: April 2003

Two kinds of itaconamic esters, α‐substituted acrylate derivatives (IAE‐I) and α‐substituted acrylamide derivatives (IAE‐II), as well as itaconamides (IAm) were prepared and polymerized with a radical initiator. It has been revealed that N,N‐disubstituted IAE‐I as an acrylate is more reactive in polymerization than N,N‐disubstituted IAE‐II as an acrylamide and that N,N′‐dialkyl substituted IAm homopolymerizes but N,N,N′,N′;‐tetraalkyl substituted one does not. In radical copolymerization with styrene, IAE‐I showed a higher polymerization reactivity than IAE‐II. The effects of the N‐substituents on the polymerization reactivity were discussed on the basis of conformation of the monomers. The polymers obtained were also characterized. © 1994 John Wiley & Sons, Inc.
Synthesis and properties of poly(arylene ether phenyl‐s‐triazine)s
Authors: Matsuo Shigeru
Published: April 2003

A series of new poly(arylene ether phenyl‐s‐triazine)s was prepared by the nucleophilic aromatic substitution polymerization of the potassium salt of bisphenols with 2,4‐bis (halophenyl)‐6‐phenyl‐s‐triazine in N‐methyl‐2‐pyrrolidone at elevated temperature. The polymers with inherent viscosities exceeding 0.5 were obtained after polymerization for 1 h using 2,4‐bis(fluorophenyl)‐6‐phenyl‐s‐triazine as a monomer. The glass transition temperatures of the resulting polymers ranged from 200 to 260°C depending on the bisphenol used in the polymer synthesis. The poly(arylene ether phenyl‐s‐triazine)s demonstrated excellent thermal stabilities in excess of 490°C (5% weight loss in air). The isothermal TGA measurements (400°C under air or nitrogen atmosphere) revealed that the 4,4'‐biphenol‐ and hydroquinone‐based poly(arylene ether phenyl‐s‐triazine)s belong to the most superior class of heat resistant polymers, such as polyimide Kapton™. The mechanical properties of these polymers are also described. © 1994 John Wiley & Sons, Inc.
Synthesis of thermotropic liquid crystal polyimide and its properties
Authors: Asanuma Tadashi , Oikawa Hideaki , Ookawa Yuuichi , Yamasita Wataru , Matsuo Mitunori , Yamaguchi Akihiro
Published: April 2003

Thermotropic liquid crystal polyimide which has neither an ester linkage nor a carbonate linkage was prepared by the polymerization of 1,2,4,5‐benzenetetracarboxylic dianhydride (PMDA) and 1,3‐bis[4‐(4′‐aminophenoxy)cumyl)]benzene (BACB). This polyimide shows the liquid crystal phase at 549‐593 K. Mixing this liquid crystal polyimide or copolymerizing BACB decreases the melt viscosity of the thermoplastic polyimide (Aurum). © 1994 John Wiley & Sons, Inc.
Preparation of poly(phosphate ester)s having bisphenol moieties as mesogenic units in the main chain
Authors: Sugiyama Kazuo , Makino Koji , Morita Masao , Yoshimitsu Yoshikuni
Published: April 2003

Poly(phosphate ester)s, PPE 1a–d, were synthesized from polycondensation of methyl phosphorodichloridate (MPDC) with various bisphenols such as 4,4′‐biphenol 1a, 4,4′‐dihydroxyphenylether 1b, bis(4‐hydroxyphenyl)methane 1c, and 3,3′‐dimethyl‐4,4′‐dihy‐droxybiphenyl 1d. PPE 2a–d with hexamethylene spacers were also obtained from poly‐condensation of MPDC with 4,4′‐bis(6‐hydroxyhexyloxy)biphenyl 2a, 4,4′‐di(6‐hydroxyhexyloxy)phenyl ether 2b, bis[4‐(6‐hydroxyhexyloxy)phenyl]methane 2c, and 3,3′‐dimethyl 4,4′‐di(6‐hydroxyhexyloxy)biphenyl 2d. The degree of crystallinity of PPE 1a–1d without hexamethylene spacer was 3.3–17.6%, whereas PPE 2a and PPE 2b which exhibit mesomorphic behavior were 20.1 and 18.6%, respectively. PPE 2a and PPE 2b show the mesophase at 139.6–195.5°C and 42.4–66.3°C, respectively. PPE 2c and PPE 2d were obtained as rubbery. From pyrolysis of PPE in air the temperature corresponding to 5% weight loss was found to be 322–408°C and 284–291°C for PPE 1 and PPE 2, respectively. It was also found that PPE 2a was enzymatically degraded by phospholipase C. © 1994 John Wiley & Sons, Inc.
Photo‐initiated base‐formation in a polymer matrix
Authors: Ito Ken‐Ichi , Nishimura Masamichi , Sashio Minoru , Tsunooka Masahiro
Published: April 2003

It was found that amines were formed efficiently by the photolysis of O‐acyloximes followed by hydrolysis in polystyrene films and the relationship between structures of O‐acyloximes and yields of amines were investigated. O‐phenylacetyl acetophenone oxime (PaApO), O‐pivaloyl acetophenone oxime (PApO), and O‐benzoyl acetophenone oxime (BApO) as monofunctional O‐acyloximes and O,O′‐succinyl diacetophenone oxime (SDApO) and O,O′‐glutaryl diacetophenone oxime (GDApO) as bifunctional O‐acyloximes were examined. The yields of amines for PaApO and SDApO under N2 were ca. 70%, which was the highest among O‐acyloximes examined in this experiment. On the other hand, the yields for PApO, BApO, and GDApO were less than 15% and it was verified that the hydrogen abstraction by imino radicals via 6‐membered cyclic intermediates resulted in the lowering of yields. Although the effect of oxygen under photolysis on the yields of amine for PaApO was negligible under 50% conversion of PaApO, the yield decreased with further increase in the conversion and was 50% at 90% conversion. © 1994 John Wiley & Sons, Inc.
New fluorinated oxazoline block copolymer lowers the adhesion of platelets on polyurethane surfaces
Authors: Kaku Mureo , Grimminger Lisa C. , Sogah Dotsevi Y. , Haynie Sharon I.
Published: April 2003

We have prepared an amphiphilic oxazoline block copolymer of hydrophilic poly(2‐methyl‐2‐oxazoline) and hydrophobic poly[2‐(2‐perfluorooctyl)ethyl‐2‐oxazoline] chains. By controlling the length and composition of polymer chains, we found that this fluorinated block copolymer can be readily dissolved in water. Furthermore, we can achieve a stable surface coating of the fluorinated block copolymer by dissolving the copolymer in water, then coating the aqueous copolymer solution onto surfaces of nonwater‐soluble polymers. This is a simple and useful method of modifying the surface character of polymer substrates. We have found that the polyether urethane (PEU) coated by block copolymer has a different surface chemistry and biological reactivity than the uncoated PEU. From XPS analysis, we found the fluorinated copolymer was coated on PEU (atomic % of F: 31.3 on coated PEU, 0.3 on uncoated). The two surfaces have different affinities for biological molecules. Specifically, the fibrinogen adsorption on the fluorinated copolymer‐coated PEU was 62 ± 39 ng/cm2, compared to a value of 156 ± 99 ng/cm2 for uncoated PEU. In an ex vivo evaluation of platelet adhesion, the surface of coated PEU attached a few white cells while uncoated PEU was covered with activated platelets. © 1994 John Wiley & Sons, Inc.
Dipole–dipole interaction directed liquid crystalline polymers. I. Aliphatic poly(carbonate‐sulfone)s based on 1,3‐bis(3‐hydroxypropylsulfonyl)propane
Authors: Zhang Tianhong , Litt Morton H. , Rogers Charles E.
Published: April 2003

Aliphatic poly(carbonate‐sulfone) homo‐ and copolymers were prepared from 1,3‐bis(3‐hydroxypropylsulfonyl)propane (Diol‐333) and various alkanediols. The copolymers are random in nature since they were prepared by melt copolymerization. Both the homopolymer and the copolymers exhibited multiple reproducible first‐order transitions during differential scanning calorimetry (DSC) heating scans, but most of them exhibited only single exotherm during cooling scans. Typical schlieren textures were observed when these polymers were cooled from their isotropic melts. The copolymers have wide‐angle x‐ray diffraction (WAXD) patterns almost identical to that of the homopolymer except in the low‐angle spacing, indicating their packing in the crystalline domain in similar. DSC, cross‐polarized optical microscopy, and WAXD revealed that these polymers were smectic liquid crystalline at room temperature. Since aliphatic poly(carbonate‐sulfone)s are flexible linear polymers with no rigid rod components, the liquid crystalline phase formation is probably directed by the dipole–dipole interactions between sulfone groups in adjacent chains. © 1994 John Wiley & Sons, Inc.
Hydrolyzable poly(ester‐urethane) networks from L‐lysine diisocyanate and D,L‐lactide/ϵ‐caprolactone homo‐ and copolyester triols
Authors: Storey R. F. , Wiggins J. S. , Puckett A. D.
Published: April 2003

Bioabsorbable poly(ester‐urethane) networks were synthesized from ethyl 2,6‐diisocyanatohexanoate (L‐lysine diisocyanate) (LDI) and a series of polyester triols. LDI was synthesized by refluxing L‐lysine monohydrochloride with ethanol to form the ester, which was subsequently refluxed with 1,1,1,3,3,3‐hexamethyldisilazane to yield a silazane‐protected intermediate. This product was then phosgenated using triphosgene. Polyester triols were synthesized from D,L‐lactide, ϵ‐caprolactone, or comonomer mixtures thereof, using glycerol as initiator and stannous octoate as catalyst. Polyurethane networks were cured using [NCO]/[OH] = 1.05 and stannous octoate (0.05 wt %) for 24 h at room temperature and pressure and 24 h at 50°C and 0.1 mm Hg. LDI‐based polyurethane networks were totally amorphous and possessed very low sol contents. Networks based on poly (D,L‐lactide) triols were rigid (Tg ∽ 60°C) with ultimate tensile strengths of ∼ 40–70 MPa, tensile moduli of ∼ 1.2–2.0 GPa, and ultimate elongations of ∼ 4–10%. Networks based on ϵ‐caprolactone triols were low‐modulus elastomers with tensile strengths and moduli of ∼ 1–4 MPa and ∼ 3–6 GPa, respectively, and ultimate elongations of ∼ 50–300%. Networks based on copolymers displayed physical properties consistent with monomer composition and were tougher than the networks based on the homopolymers. Tensile strengths for the copolymers were ∼ 3–25 MPa with ultimate elongations up to 600%. Hydrolytic degradation under simulated physiological conditions showed that D,L‐lactide homopolymer networks were the most resistant to degradation, undergoing virtually no change in mass or physical properties for 60 days. ϵ‐Caprolactone‐based networks were resistant to degradation for 40 days, and high‐lactide copolymer‐based networks suffered substantial losses in physical properties after only 3 days. © 1994 John Wiley & Sons, Inc.
Polymerization of propylene by zirconocenium catalysts with different counter‐ions
Authors: Chien James C. W. , Song Wei , Rausch Marvin D.
Published: April 2003

Propylene was polymerized by binary zirconocenium catalysts derived from rac‐ethylenebis(1‐η5‐indenyl)dimethylzirconium and cation forming agents (C6H5)3C+(C6F5)4B− and (C6F5)3B. Polymerizations were also performed with the ternary systems of Et[Ind]2ZrCl2, Et3Al, and the cation forming agents. The catalyst systems, with the inert noncoordinating counter‐ion, (C6F5)4B−, have much higher activity and stereoselectivity than the ones with the CH3B−(C6F5)3 counter‐ion. Much less active still are catalysts having BF4− or (C6H5)4B− counter‐ions. Similar but smaller effects of counter‐ion structure on ethylene polymerization were observed. © 1994 John Wiley & Sons, Inc.
Hindered lithium dialkylamide initiators for the living anionic polymerization of methacrylic esters
Authors: Long T. E. , Guistina R. A. , Schell B. A. , Mcgrath J. E.
Published: April 2003

Lithium diisopropylamide is an efficient initiator for the anionic polymerization of methyl methacrylate in polar solvents at –78°C. Predictable molecular weights based on the initiator concentration were obtained, yields were quantitative, and molecular weight distributions were relatively narrow (<1.30). The presence of an amino end group and confirmation of the initiation mechanism were confirmed by potentiometric titration using HClO4. Number‐average molecular weights determined by titration agreed well with values determined by SEC. Other lithium dialkylamides that contain larger alkyl groups such as lithium diisobutylamide were less efficient initiators. This was attributed to the more nucleophilic anion due to less steric hindrance near the nitrogen atom. Molecular weight distributions were significantly broadened (>2.0), and molecular weight control was not achieved. However, polymer yields were quantitative. In all cases, PMMA stereochemistry was indicative of a solvent‐separated lithium counterion, and triad compositions were identical to organolithium initiated homopolymers, i.e., 78% syndiotactic, 20% heterotactic, and 2% isotactic. © 1994 John Wiley & Sons, Inc.
Synthesis and properties of poly (diphenylacetylenes) having aliphatic para‐substituents
Authors: Kouzai Hiroaki , Masuda Toshio , Higashimura Toshinobu
Published: April 2003

1‐(p‐t‐Butylphenyl)‐2‐phenylacetylene and 1‐(p‐n‐butylphenyl)‐2‐phenylacetylene were polymerized in catalytic systems based on TaCl5 to give new polymers in high yields. These monomers were more reactive than diphenylacetylene (DPA) in copolymerization. Unlike poly (DPA), the present polymers were soluble in toluene, CHCl3, etc. owing to the high configurational entropy induced by the para‐substituents. Their relative weight‐average molecular weights determined by GPC were in the range of 6 × 105–36 × 105, and films could be obtained by solution casting. These polymers were fairly thermally stable, as seen from their high onset temperatures (320–380°C) of weight loss in TGA in air. The oxygen permeability coefficient of the polymer with t‐Bu group was 1100 barrers, the highest among those of all the hydrocarbon polymers. © 1994 John Wiley & Sons, Inc.
Cationic ring‐opening polymerization of oxetane derivatives initiated by superacids: Studies on their propagating mechanism and species by means of 19F‐NMR
Authors: Liu Ying‐Ling , Hsiue Ging‐Ho , Chiu Yie‐Shun
Published: April 2003

The nature of ring‐opening polymerization of oxetane derivatives initiated by triflic acid and triflic anhydride was investigated via 19F‐NMR spectroscopy. Two types of propagating species, which were directly observed from the 19F‐NMR spectra, were found to be oxonium macroions and triflic macroesters. These two propagating species established and equilibrium relationship during the polymerization process. The forming of oxonium macroion active species was highly dependent upon the substituents of the oxetane ring, and were enhanced when a more polar solvent was employed. The initiator effect, which occurred primarily in the initiating stage of the polymerization, is also discussed. © 1994 John Wiley & Sons, Inc.
Dual‐Phase structure of polymer electrolytes comprised of NBR/SBR latex films swollen with lithium salt solution
Authors: Matsumoto Morihiko , Ichino Toshihiro , Rutt J. Steven , Nishi Shiro
Published: April 2003

Dual‐phase polymer electrolytes (DPE) that have high ionic conductivity (> 10−3 S/cm) and good mechanical strength were prepared by mixing NBR and SBR latices and casting films. The latex films absorbed large quantities of lithium salt solution (e.g., 1M lithium perchlorate in γ‐butyrolactone) to obtain DPE films but did not dissolve with swelling. The NBR phase is polar and was impregnated selectively with the polar lithium salt solution, whereas the SBR phase is nonpolar and formed a mechanically‐supportive matrix. Transmission electron microscopic (TEM), electron energy loss spectral (EELS), and energy‐dispersive x‐ray (EDX) analyses showed microscopically the dual‐phase structure. Evidence for swelling by lithium salt solution was found only in the NBR phase and not in the SBR phase by EDX microanalysis. Ionic conductivity as a function of NBR content or swelling degree showed clearly that a percolation threshold for ionic conductivity exists. © 1994 John Wiley & Sons, Inc.
Solution viscosity behavior of polystyrene‐based cationic ionomers. Effects of ion content and solvent
Authors: Ohtani Noritaka , Inoue Yukihiko , Mizuoka Hiroshi , Itoh Kenya
Published: April 2003

Dilute‐solution viscosities of polystyrene‐based cationic ionomers containing ammonio or phosphonio groups were measured in several solvents. In polar solvents with dielectric constant (εr) beyond 10, the ionomers showed a typical polyelectrolyte behavior, indicating that a large part of ionic groups were dissociated into ions. In nonpolar solvents with low εr, the reduced viscosity of the ionomers linearly decreased with a decreasing ionomer concentration. At low polymer concentrations, every ionomer gave a reduced viscosity lower than that of the corresponding chloromethylated polystyrene. With an increasing ion content, the intrinsic viscosity progressively decreased if the nonpolar solvents had a low acceptor number (AN), such as toluene or tetrahydrofran (THF). In the halogenated solvents with high AN value, such as chloroform, however, the intrinsic viscosity was hardly dependent on the ion content. This indicates that the intramolecular aggregation among the ionic groups is inhibited in the halogenated solvents due to a strong anion solvation. An addition of a protic solvent to a nonpolar solvent eliminates the aggregation between ionic groups and leads to polyelectrolyte behavior. © 1994 John Wiley & Sons, Inc.
Miscibility study in the blends of novel poly (styrene‐co‐4‐vinylphenyldimethylsilanol) and poly (n‐butyl methacrylate)
Authors: Lu Shaoxiang , Pearce Eli M. , Kwei T. K.
Published: April 2003

The miscibility of poly (styrene‐co‐4‐vinylphenyldimethylsilanol) (ST‐VPDMS) and poly (n‐butyl methacrylate) (PBMA) blends has been investigated by means of DSC and FT‐IR spectroscopy. It was found that miscible blends were formed only for the copolymers containing 9–34 mol % 4‐vinylphenyldimethylsilanol (VPDMS). The glass transition behavior of the miscible blends was analyzed by recently proposed equations in terms of the physical meaning of the fitting parameters. The results of FT‐IR study were found to be fully consistent with the observation of the miscibility window obtained from glass transition temperature measurements. Quantitative information concerning intermolecular hydrogen bond interaction in the carbonyl stretching vibration region of the miscible blends was obtained by curve‐fitting method. © 1994 John Wiley & Sons, Inc.
New poly(amide‐imide) syntheses. XII. Preparation and properties of poly(amide‐imide)s based on the diimide‐diacid condensed from 9,9‐bis[4‐(4‐aminophenoxy)phenyl] fluorene and trimellitic anhydride
Authors: Yang Chin‐Ping , Lin Jiun‐Hung
Published: April 2003

A dicarboxylic acid (I) was prepared from the condensation of 9,9‐bis[4‐(4‐aminophenoxy) phenyl] fluorene and trimellitic anhydride. A new family of poly(amide‐imide)s having inherent viscosities of 0.75‐1.04 dL/g was prepared by the triphenyl phosphite activated polycondensation from the diimide‐diacid I with various aromatic diamines in a medium consisting of N‐methyl‐2‐pyrrolidone (NMP), pyridine, and calcium chloride. Most of the resulting polymers showed an amorphous nature and were readily soluble in polar solvents such as NMP and N,N‐dimethylacetamide. All the soluble poly(amide‐imide)s afforded transparent, flexible, and tough films. The glass transition temperatures of these polymers were in the range of 262–325°C and the 10% weight loss temperatures were above 525°C in air. © 1994 John Wiley & Sons, Inc.
Multifunctional coupling agents for living cationic polymerization. IV. Synthesis of end‐functionalized multiarmed poly(vinyl ethers) with multifunctional silyl enol ethers
Authors: Fukui Hiroji , Sawamoto Mitsuo , Higashimura Toshinobu
Published: April 2003

Telechelic (8) and end‐functionalized four‐arm star polymers (9) were synthesized through the coupling reactions of end‐functionalized living poly(isobutyl vinyl ether) (5; DPn ∼ 10) with the bi‐and tetrafunctional silyl enol ethers, H4‐nC[CH2OC6H4C(OSiMe3) = CH2]n (3: n = 2; 4: n = 4). The precursor polymers 5 were prepared by living cationic polymerization with functionalized initiators, CH3CH(Cl)OCH2CH2X(6), in conjunction with zinc chloride in methylene chloride at −15°C. The initiators 6 were obtained by the addition of hydrogen chloride gas to vinyl ethers bearing pendant functional groups X, including acetoxy [OC(O)CH3], styryl (OCH2C6H4‐p‐CH = CH2), and methacryloyl [OC(O)C(CH3) = CH2]. The coupling reactions with 3 and 4 in methylene chloride at −15°C for 24 h afforded the end‐functionalized multiarmed polymers (8 and 9) in high yield (>91%), where those with styryl or methacryloyl groups are new multifunctional macromonomers. © 1994 John Wiley & Sons, Inc.
A novel palladium catalyst for the polymerization of propargyl alcohol
Authors: Yang Mujie , Zheng Min , Furlani Anita , Russo Maria Vittoria
Published: April 2003

Homogeneous polymerization of propargyl alcohol (OHP) with Pd (CCCH2OH)2(PPh3)2 [PdC] catalyst in CHCl3‐CH3OH mixed solvent system has been investigated. [PdC] was found to be a novel effective catalyst for the OHP polymerization. Some features, kinetic behavior, and effect of solvent for the OHP polymerization are described and discussed. The overall polymerization activation energy was found to be 75.6kJ/mol and the rate equation can be expressed as Rp = kp[OHP] [PdC]0.7, where kp = 3.14 × 10‐4 L0.7/ mol0.7 S (60°C). Polypropargyl alcohol (POHP) obtained is a brown powder with a number‐average molecular weight (M̄n) of 103‐2 × 103, and soluble in MeOH, DMF, and DMSO. Conducting properties of the resulting POHP were investigated. © 1994 John Wiley & Sons, Inc.
Phase‐mixed poly(ethylene glycol)/poly(trimethylolpropane triacrylate) semi‐interpenetrating polymer networks obtained by rapid network formation
Authors: Drumheller Paul D. , Hubbell Jeffrey A.
Published: April 2003

Semi‐interpenetrating polymer networks (semi‐IPNs) of poly(ethylene glycol) (PEG) in poly(trimethylolpropane triacrylate) (TMPTA) were synthesized from PEG melts in neat TMPTA monomer, using PEG of molecular weights from 4000 to 100,000 g/mol. Differential scanning calorimetry and transmission electron microscopy were used to examine phase separation occurring during network formation. The degree of phase separation was observed to depend upon the rate of PEG aggregation relative to the rate of network formation during TMPTA polymerization. Higher molecular weight PEG and acrylate‐functionalized PEG formed more phase‐mixed networks compared to lower molecular weight PEG; acetatefunctionalized PEG showed no difference from unmodified PEG in the extent of phase mixing. For networks that demonstrated phase separation, the PEG was observed to be in two states: some being phase mixed and solvent inextractable, and some being phase separated and solvent extractable. Phase‐mixed networks could be obtained from this thermodynamically incompatible polymer pair utilizing rapid photopolymerization systems to overcome PEG phase aggregation and kinetically entrap the PEG in a nonequilibrium phase‐mixed state. These mixed‐phase semi‐IPNs of PEG and TMPTA may be useful in biological applications where the presence of PEG is desired throughout the bulk matrix rather than as a surface graft to reduce biological interactions. © 1994 John Wiley & Sons, Inc.
Radical polymerization of methyl acrylate by use of benzyl N, N‐diethyldithiocarbamate in combination with tetraethylthiuram disulfide as a two‐component iniferter
Authors: Doi Toru , Matsumoto Akikazu , Otsu Takayuki
Published: April 2003

Polymerization of methyl acrylate (MA) with benzyl N, N‐diethyldithiocarbamate (BDC) was carried out in bulk or in benzene under UV irradiation. The polymerization proceeded to give a high yield of polymer, however it was found that BDC did not function as an iniferter in the MA polymerization. Bimolecular termination leading to deactivation of the iniferter site was observed during the polymerization in preference to chain transfer and primary radical termination which reproduce the iniferter site. The deactivation was successfully prevented by combining BDC and tetraethylthiuram disulfide (TD) as a two‐component iniferter. This two‐component iniferter system was also applied to synthesis of a star polymer with 1,2,4,5‐tetrakis (N,N‐diethyldithocarbamylmethyl) benzene (DDC) as a tetrafunctional photoiniferter. © 1994 John Wiley & Sons, Inc.
Selective extraction of Fe3+ by a polymeric calix[4]arene
Authors: Deligöz Hasalettin , Tavasli Mustafa , Yilmaz Mustafa
Published: April 2003

A polymeric compound containing more than one calixarene molecule was synthesized by reacting the oligomer (2) with 25,26,27‐tribenzoyloxy‐28‐hydroxy calix[4]arene. After basic hydrolysis of 3a, the polymeric calixarene (3b) was utilized for selective extraction of some metal cations from aqueous phase to organic phase. It was found that the compound (3b) was selective toward Fe3+ from an aqueous solution containing Cu2+, Ni2+, Co2+ and Fe3+ cations. The mechanism of the extraction process was discussed. © 1994 John Wiley & Sons, Inc.
Mechanism of lactide polymerization in the presence of stannous octoate: The effect of hydroxy and carboxylic acid substances
Authors: Zhang Xichen , MacDonald David A. , Goosen Mattheus F. A. , McAuley Kim B.
Published: April 2003

The effect of hydroxy and carboxylic acid substances on lactide polymerization in the presence of stannous octoate was investigated. A polymerization mechanism was postulated to attempt to explain the controversies existing in the literature and also to explain our experimental observations. Stannous alkoxide, a reaction product between stannous octoate and alcohol, is proposed as the substance initiating the polymerization through coordinative insertion of lactide. Alcohol can affect the polymerization through the reactions of initiator formation, chain transfer, and transesterfication. Carboxylic acid affects the polymerization through a deactivation reaction. Experiments showed that alcohol increased PLLA production rate while carboxylic acid decreased it. Both alcohol and carboxylic acid reduced PLLA final molecular weight. The higher the alcohol concentration, the lower the polymer molecular weight. However, the final molecular weight of PLLA was not sensitive to the carboxylic acid concentration. A polymerization induction period was observed at high carboxylic acid concentration, due to the deactivation reaction caused by carboxylic acid. © 1994 John Wiley & Sons, Inc.
A comparison of thermoreactive water‐soluble poly‐N,N‐diethylacrylamide prepared by anionic and by group transfer polymerization
Authors: Freitag Ruth , Baltes Thomas , Eggert Martin
Published: April 2003

Several batches of poly‐N,N‐diethylacrylamide were synthesized by anionic and by group transfer polymerization (GTP). A radical poly‐N,N‐diethylacrylamide prepared from the same monomer was also included in the comparison. According to matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) both types of living polymerization resulted in narrow molecular weight distributions with Mw/Mn values below 1.5. Average molecular weights (Mn) between 888 and 4678 g/mol were calculated in these cases. The radical polymer had an average molecular weight (Mn) of approximately 130,000 g/mol. The dry anionic and GTP polymers were investigated by differential scanning calorimetry (DSC) and x‐ray diffraction spectrometry. Evidence for partial crystallinity in the solid state was found. The conformation of all polymers was examined by high resolution (600 MHz) NMR. According to these measurements, 75% of the CHR groups of the anionic poly‐N,N‐diethylacrylamide were located in an isotactic triade. The remaining 25% had heterotactic structure, while no indication for the presence of syndiotactic protons was found. Poly‐N,N‐diethylacrylamide prepared by GTP, on the other hand, had mainly syndiotactic structure. The aqueous solutions of the polymers showed phase separation upon heating. Whereas the lower critical solution temperature (LCST) was approximately 30°C in the case of the poly‐N,N‐diethylacrylamide prepared by GTP and by radical polymerization, uncommonly high LCSTs of more than 40°C were observed for the anionic poly‐N,N‐diethylacrylamide. © 1994 John Wiley & Sons, Inc.
Synthesis and characterization of 3‐aryl‐2‐(polystyryl)cyclopropenones via cyclopropenium ion substitution on polystyrene
Authors: Weidner C. H. , Long T. E.
Published: April 2003

Electrophilic substitution of cyclopropenium ions on aromatic polymers offers a unique opportunity to introduce polar functionality in a controlled manner to conventional, nonpolar polymers. Phenylcyclopropenone substituted polystyrene with predictable chemical composition and narrow molecular weight distribution were prepared. Size exclusion chromatography (SEC) analysis demonstrated the absence of branching or crosslinking in these functionalized polystyrenes during electrophilic substitution of the parent homopolymer. 13C‐NMR confirmed that the degree of phenylcyclopropenone substitution was both highly efficient and predictable over a broad compositional range. The glass transition temperature (Tg) of the polymers was found to vary linearly with mole % phenylcyclopropenone substitution of the polystyrene. Thermal gravimetric analysis (TGA) indicated that thermal decarbonylation of the appended cyclopropenones occurred at approximately 180°C. Weight loss vs. temperature profiles correlated reasonably well with levels of substitution based on 13C‐NMR analysis, confirming that decarbonylation of the calculated cyclopropenone substituents was the predominant thermal decomposition pathway. © 1995 John Wiley & Sons, Inc.
Complex‐radical terpolymerization of phenanthrene, maleic anhydride, and trans‐stilbene
Authors: Bastürkmen Meray , Rzaev Zakir M. O. , Akovali Güneri , Kisakürek Duygu
Published: April 2003

The radical terpolymerization of the donor‐acceptor‐donor monomer system, phenanthrene (P)—maleic anhydride (M)—trans‐stilbene (S), was studied. These monomers are known to be nonhomopolymerizable. The terpolymerization was carried out in p‐dioxane and/or toluene at 70°C in the presence of benzoyl peroxide used as the initiator. P and S were found to form charge transfer complexes (CTC) with M in p‐dioxane at 35°C. The results obtained are discussed in terms of the free monomer and complex propagation models. It is shown that terpolymerization is carried out at a stage close to binary copolymerization of two complexomers. The reactivity ratio of P … M and S … M complexes was estimated by the Kelen‐Tüdös method. Absorbance ratios at 1770 cm−1 (vC=0 of anhydride group), 764 cm−1 (δCH in monosubstituted benzene of S), and 820 cm−1 (δCH in disubstituted benzene of P) as a function of terpolymer composition were established. P—M—S terpolymers are shown to have high thermal stabilities. © 1995 John Wiley & Sons, Inc.
Preparation of poly(methyl methacrylate) and copolymers having enhanced thermal stabilities using sucrose‐based comonomers and additives
Authors: Sachinvala Navzer D. , Ju Ruei F. (Redford) , Litt Morton H. , Niemczura Walter P.
Published: April 2003

A series of methyl methacrylate polymers have been prepared containing sucrose‐based crosslinkers and additives. Thermogravimetry and long‐term aging studies at 200°C show that sucrose‐based alkyl and allyl ethers provide unprecedented thermal stability to linear, as well as crosslinked, poly (methyl methacrylate) or PMMA. Linear PMMA and PMMA crosslinked with trimethylolpropane trimethacrylate (TMPTMA) both degrade at 284°C. PMMA containing octa‐O‐crotylsucrose (1 mol %) degraded at 322°C. Depending on concentration, PMMA containing octa‐O‐allylsucrose (0.1‐1.0 mol % and higher) degraded between 334 and 354°C, and PMMA containing 1′,6,6′‐trimethacryloyl‐2,3,3′,4,4′‐penta‐O‐methylsucrose (0.1‐1.0 mol %) degraded between 309 and 320°C. PMMA containing (1 mol % each) sucrose‐based esters, ester‐ether derivatives, all degraded at or below the degradation temperature of pure PMMA. Long‐term air aging studies revealed that PMMA containing penta‐O‐methylsucrose trimethacrylate, octa‐O‐allylsucrose, and octa‐O‐crotylsucrose did not flow or sag after heating for 24 h at 200°C, but the polymers did show yellowing. While linear and crosslinked samples of PMMA containing compounds other than sucrose ethers lost more than 50% of their original weight within 15 h at 200°C, PMMA containing sucrose‐based ethers lost about 8 and 20% of their original weight after 1 and 8.5 days, respectively. Herein we propose a unique mechanism by which saccharide ethers may be imparting this unprecedented thermal stabilization to PMMA. While tertiary hydrogens alpha to oxygens in saccharide ethers are stable to chain transfer during normal polymerization temperatures, they readily chain transfer at 200°C where PMMA is unstable. Chain transfer of these hydrogens is followed by fragmentation to produce alkyl, allyl or crotyl radicals, which combine with the macroradicals and terminate depropagation. © 1995 John Wiley & Sons, Inc.
Monomer‐isomerization polymerization. XXXVIII. Monomer‐isomerization copolymerizations of styrene and 2‐Butene with Ziegler–Natta catalyst
Authors: Endo Kiyoshi , Otsu Takayuki
Published: April 2003

Monomer‐isomerization copolymerizations of styrene (St) and cis‐2‐butene (c2B) with TiCl3‐(C2H5)3Al catalyst were studied. St and c2B were found to undergo a new type of monomer‐isomerization copolymerization, i.e., only isomerization of 2B to 1‐butene (1B) took place to give a copolymer consisting of St and 1B units. The apparent copolymerization parameters were determined to be rst = 16.0 and rc2b = 0.003. The parameters were changed by the addition of NiCl2 (rSt = 8.4, rc2b = 0.05). The copolymers containing the major amount of St units were produced easily through monomer‐isomerization copolymerization of St and 2B. © 1995 John Wiley & Sons, Inc.
Convenient esterification of poly(γ‐glutamic acid) produced by microorganism with alkyl halides and their thermal properties
Authors: Kubota Hidetoshi , Nambu Yoko , Endo Takeshi
Published: April 2003

The esterification of poly(γ‐glutamic acid) (γ‐PGA) produced by Bacillus subtilis F2‐01 with alkyl halides was carried out at 60°C in N‐methyl‐2‐pyrrolidinone (NMP) in the presence of sodium bicarbonate to obtain the corresponding esterified γ‐PGA. The thermal properties of these γ‐PGA esters were examined by differential scanning calorimetry and thermogravimetry. γ‐PGA esters were more stable than free acid type γ‐PGA, which decomposed at 210°C. Melting temperature (Tm) of γ‐PGA esters could be observed at 230‐250°C. Tm of γ‐PGA n‐alkyl esters reached a maximum at an alkyl chain length of n = 3. © 1995 John Wiley & Sons, Inc.
Biocatalytic synthesis of polymers. III. Formation of a high molecular weight polyester through limitation of hydrolysis by enzyme‐bound water and through equilibrium control
Authors: Brazwell Eugenia M. , Filos Dianela Y. , Morrow Cary J.
Published: April 2003

Enzyme‐catalyzed preparation of polymers offers several potentially valuable advantages over the usual polymerization procedures and has been studied for several years. A significant limitation on the polyesters prepared to date has been the low molecular weights achieved. The present studies have established that, in the polycondensation of bis(2,2,2‐trifluoroethyl) glutarate with 1,4‐butanediol using porcine pancreatic lipase as the catalyst, this limitation arises from at least two sources: hydrolysis of activated ester end groups by water introduced along with the enzyme and the polymerization's reaching equilibrium despite using the poorly nucleophilic 2,2,2‐trifluoroethanol as the leaving group. Evidence is also developed that the presence of trifluoroethanol accelerates the release of the enzyme‐bound water which hydrolyzes the activated ester end groups. The hydrolysis could be avoided by choosing a relatively high‐boiling solvent, such as bis(2‐ethoxyethyl) ether, then removing the trifluoroethanol by placing the reaction mixture under vacuum periodically or by drying the enzyme rigorously. The vacuum method also removed the limitation on molecular weight resulting from the reaction's reaching equilibrium. A further improvement in the molecular weight to nearly 40,000 daltons, well within the range that is technically interesting, was achieved by using 1,2‐dimethoxybenzene or 1,3‐dimethoxybenzene as the polymerization solvent. © 1995 John Wiley & Sons, Inc.
Molecular mechanics study of zirconocenium catalyzed isospecific polymerization of propylene
Authors: Yu Zhengtian , Chien James C. W.
Published: April 2003

Stereocontrol energy (ΔE0) is investigated as a measure of enantioselectivity of ansa‐zircoocenium catalyst in propylene polymerization; it was calculated with MM2 (molecular mechanics) force field using π complex (°C) and transition state (TS) geometries obtained by ab initio molecular orbital methods. Both rac‐ethylenebis (1‐η5‐indenyl) ‐ (1) and rac‐ethylenebis (1‐η5‐4,5,7,8‐tetrahydroindenyl) (2) zirconocenium species are isospecific in either the π‐complexes or the transition states. The stereoselectivity is greater if there is α‐agostic interaction; it is lowered in the cases of β and γ agostic interactions. The 13C‐NMR steric pentad distribution indicates the poly(propylene) to be much less stereoregular than that predicted by ΔE0. Following the occurrence of a regiochemical insertion error, the addition of another monomer via any mode is prohibitively unfavorable. The catalyst suffers loss of stereospecificity as temperature of polymerization increases. Insertion via transition states involving different agostic interactions could be one explanation for the observed loss. © 1995 John Wiley & Sons, Inc.
Epoxy‐amine multimethacrylic prepolymers, kinetic and structural studies
Authors: Titier Christelle , Pascault Jean‐Pierre , Taha Mohamed , Rozenberg Boris
Published: April 2003

Epoxy‐amine methacrylated prepolymers are prepared in a 1‐step synthesis by the reaction of Bisphenol A diglycidyl ether, glycidyl methacrylate, and different diamines. The adaptation of these reactions to production processes with a reduced reaction time requires a kinetic control and the use of efficient catalysts. The comparative kinetic treatment of the epoxy‐amine reaction in the frame of Horie's and Rozenberg's kinetic schemes have been made. Cases where an efficient acid catalyst is used are also examined. Structural studies of these reactions established the occurrence of a Michael amine/double bond addition, when some amines are used. © 1995 John Wiley & Sons, Inc.
The photochemistry of polymers containing anthrylmethyl vinyl ketone
Authors: Modi Pankaj J. , Guillet James E.
Published: April 2003

The photolysis of copolymers of anthrylmethyl vinyl ketone (AMVK) with styrene and methyl methacrylate has been studied, both in solution and in the solid phase. Quantum yields of the order of 0.01 were observed in both cases for release of the major product, methyl anthracene (MA). Photolysis of an aqueous emulsion of a styrene‐AMVK copolymer showed similar yields of MA. The results indicate the possibility of using the Norrish type I process as a means of releasing drugs or other biologically active compounds from polymeric matrices. © 1995 John Wiley & Sons, Inc.
Synthesis and metal binding behavior of hydroxamic acid resins from poly(ethyl acrylate) crosslinked with divinylbenzene and hydrophilic crosslinking agent
Authors: Lee Taek Seung , Hong Sung Il
Published: April 2003

Porous poly(hydroxamic acid) chelating resin was prepared by the reaction with poly(ethyl acrylate) crosslinked with divinylbenzene and hydrophilic crosslinking agent, and hydroxylamine. The hydrophilic crosslinking agents and diluent used in this article were ethylene glycol dimethacrylate or butanediol dimethacrylate, and 2,2,4‐trimethyl pentane, respectively. The characterization of this type chelating resin was carried out by IR spectroscopy, density measurement, and scanning electron microscopy. Various metal binding properties such as extraction, kinetics, and selectivity were investigated with atomic absorption spectrometer and inductively coupled plasma spectrometer. Poly(hydroxamic acid) resins crosslinked with mixed crosslinking agents showed better metal extraction properties and faster adsorption rate than those crosslinked with divinylbenzene alone. And alkali treatment enhances the binding rate for metal ions because of the formation of other chelating ligands or micropores. © 1995 John Wiley & Sons, Inc.
Molecular weight distributions of linear polymers: Detailed analysis from GPC data
Authors: Kissin Y. V.
Published: April 2003

The GPC method is used widely to measure molecular weights of linear polymers. High‐quality GPC data contains detailed information on many aspects of the polymer's molecular weight distribution (MWD). This information can be extracted from the data using computer analysis. Equations have been derived for the two simplest MWD functions in the GPC coordinates: the Flory function (one growing polymer chain produces one polymer molecule), and for the case when two polymer radicals combine into one polymer molecule. The equations were used to analyze MWD of two classes of polymers. The first class includes polymers with narrow MWD: polyethylene, ethylene‐propylene and ethylene‐hexene copolymers, syndiotactic polystyrene, and radical polystyrene. The second class includes polymers with broad MWD: ethylene copolymers and polypropylene produced with heterogeneous, Ti‐based catalysts. The examples demonstrate that the resolution of complex GPC curves into their constitutents serve as an important source of information about kinetics of polymerization reactions. © 1995 John Wiley & Sons, Inc.