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1.
Ren‐Shen Lee Tz‐Feng Lin Jen‐Ming Yang 《Journal of polymer science. Part A, Polymer chemistry》2003,41(10):1435-1443
The melt ring‐opening/condensation reaction of trans‐4‐hydroxy‐N‐benzyloxycarbonyl‐L‐proline (N‐CBz‐Hpr) with cyclic carbonate [trimethylene carbonate (tri‐MC) or tetramethylene carbonate (tetra‐MC)] at a wide range of molar fractions in the feed produced new degradable poly(ester‐carbonate)s. The influence of reaction conditions such as polymerization time and temperature on the yield and inherent viscosity of the copolymers was investigated. The polymerizations were carried out in bulk at 140 °C with 1.5 wt % stannous octoate as a catalyst for 30 h. The poly(ester‐carbonate)s obtained were characterized by Fourier transform infrared spectroscopy, 1H NMR, differential scanning calorimetry, gel permeation chromatography, and Ubbelohde viscometry. The copolymers synthesized exhibited moderate molecular weights with rather narrow molecular weight distributions. The values of the glass‐transition temperature (Tg) of the copolymers depend on the molar fractions of cyclic carbonate. For the poly(N‐CBz‐Hpr‐co‐tri‐MC) system, with a decreased tri‐MC content from 93 to 16 mol %, the Tg increased from ?10 to 60 °C. Similarly, for the poly(N‐CBz‐Hpr‐co‐tetra‐MC) system, when the tetra‐MC content decreased from 80 to 8 mol %, the Tg increased from ?18 to 52 °C. The relationship between the poly(N‐CBz‐Hpr‐co‐tri‐MC) Tg and the compositions was in approximation with the Fox equation. In vitro degradation of these poly(N‐CBz‐Hpr‐co‐tri‐MC)s was evaluated from weight‐loss measurements. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1435–1443, 2003 相似文献
2.
Ren‐Shen Lee Jen‐Ming Yang 《Journal of polymer science. Part A, Polymer chemistry》2005,43(8):1708-1717
A series of novel types of three‐armed poly(trans‐4‐hydroxy‐N‐benzyloxycarbonyl‐L ‐proline)‐block‐poly(ε‐caprolactone) (PHpr‐b‐PCL) copolymers were successfully synthesized via melt block copolymerization of trans‐4‐hydroxy‐N‐benzyloxycarbonyl‐L ‐proline (N‐CBz‐Hpr) and ε‐caprolactone (ε‐CL) with a trifunctional initiator trimethylolpropane (TMP) and stannous octoate (SnOct2) as a catalyst. For the homopolycondensation of N‐CBz‐Hpr with TMP initiator and SnOct2 catalyst, the number‐average molecular weight (Mn) of prepolymer increases from 530 to 3540 g mol?1 with the molar ratio of monomer to initiator (3–30), and the molecular weight distribution (Mw/Mn) is between 1.25 to 1.32. These three‐armed prepolymer PHpr were subsequently block copolymerized with ε‐caprolactone (ε‐CL) in the presence of SnOct2 as a catalyst. The Mn of the copolymer increased from 2240 to 18,840 g mol?1 with the molar ratio (0–60) of ε‐CL to PHpr. These products were characterized by differential scanning calorimetry (DSC), 1H NMR, and gel permeation chromatography. According to DSC, the glass‐transition temperature (Tg) of the three‐armed polymers depended on the molar ratio of monomer/initiator that were added. In vitro degradation of these copolymers was evaluated from weight‐loss measurements and the change of Mn and Mw/Mn. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1708–1717, 2005 相似文献
3.
Ren‐Shen Lee Zhe‐Kuan Lin Jen‐Ming Yang Feng‐Huei Lin 《Journal of polymer science. Part A, Polymer chemistry》2006,44(14):4268-4280
Novel, biodegradable poly(?‐caprolactone)‐block‐poly(trans‐4‐hydroxy‐N‐benzyloxycarbonyl‐L ‐proline)‐block‐poly(?‐caprolactone) triblock copolymers were synthesized by ring‐opening polymerization from dihydroxyl‐terminated macroinitiator poly(trans‐4‐hydroxy‐N‐benzyloxycarbonyl‐L ‐proline) (PHpr) and ?‐caprolactone (?‐CL) with stannous octoate as the catalyst. The molecular weights were characterized with gel permeation chromatography and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. With an increase in the contents of ?‐CL incorporated into the copolymers, a decrease in the glass‐transition temperature (Tg) was observed. The Tg values of copoly(4‐phenyl‐?‐caprolactone) and copoly(4‐methyl‐?‐caprolactone) were higher than Tg of copoly(?‐caprolactone). Their micellar characteristics in an aqueous phase were investigated with fluorescence spectroscopy, dynamic light scattering, and transmission electron microscopy. The block copolymers formed micelles in the aqueous phase with critical micelle concentrations in the range of 1.00–1.36 mg L?1. With higher molecular weights and hydrophobic components in the copolymers, a higher critical micelle concentration was observed. As the feed weight ratio of antitriptyline hydrochloride (AM) to the polymer increased, the drug loading increased. The micelles exhibited a spherical shape, and the average size was less than 250 nm. The in vitro hydrolytic degradation and controlled drug release properties of the triblock copolymers were also investigated. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4268–4280, 2006 相似文献
4.
Ren‐Shen Lee Jen‐Ming Yang Tz‐Feng Lin 《Journal of polymer science. Part A, Polymer chemistry》2004,42(10):2303-2312
Water‐soluble poly(ester‐carbonate) having pendent amino and carboxylic groups on the main‐chain carbon is reported for the first time. This article describes the melt ring‐opening/condensation reaction of trans‐4‐hydroxy‐N‐benzyloxycarbonyl‐L ‐proline (N‐CBz‐Hpr) with 5‐methyl‐5‐benzyloxycarbonyl‐1,3‐dioxan‐2‐one (MBC) at a wide range of molar fractions. The influence of reaction conditions such as catalyst concentration, polymerization time, and temperature on the number average molecular weight (Mn) and molecular weight distribution (Mw/Mn) of the copolymers was investigated. The polymerizations were carried out in bulk at 110 °C with 3 wt % stannous octoate as a catalyst for 16 h. The poly(ester‐carbonate)s obtained were characterized by Fourier transform infrared spectroscopy, 1H NMR, differential scanning calorimetry, and gel permeation chromatography. The copolymers synthesized exhibited moderate molecular weights (Mn = 6000–14,700 g mol?1) with reasonable molecular weight distributions (Mw/Mn = 1.11–2.23). The values of the glass‐transition temperature (Tg) of the copolymers depended on the molar fractions of cyclic carbonate. When the MBC content decreased from 76 to 12 mol %, the Tg increased from 16 to 48 °C. The relationship between the poly(N‐CBz‐Hpr‐co‐MBC) Tg and the compositions was in approximation with the Fox equation. In vitro degradation of these poly(N‐CBz‐Hpr‐co‐MBC)s was evaluated from weight‐loss measurements and the change of Mn and Mw/Mn. Debenzylation of 3 by catalytic hydrogenation led to the corresponding linear poly(ester‐carbonate), 4 , with pendent amino and carboxylic groups. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2303–2312, 2004 相似文献
5.
Yuushou Nakayama Kazuki Aihara Hitomi Yamanishi Hiroshi Fukuoka Ryo Tanaka Zhengguo Cai Takeshi Shiono 《Journal of polymer science. Part A, Polymer chemistry》2015,53(3):489-495
This article reports the synthesis and the properties of novel thermoplastic elastomers of A‐B‐A type triblock copolymer structure, where the hard segment A is poly(l ‐lactide) (PLLA) and the soft segment B is poly(ε‐caprolactone‐stat‐d ,l ‐lactide) (P(CL‐stat‐DLLA)). The P(CL‐stat‐DLLA) block with DLLA content of 30 mol % was applied because of its amorphous nature and low glass transition temperature (Tg = approximately ?40 °C). Successive polymerization of l ‐lactide afforded PLLA‐block‐P(CL‐stat‐DLLA)‐block‐PLLAs, which exhibited melting temperature (Tm = approximately 150 °C) for the crystalline PLLA segments and still low Tg (approximately ?30 °C) of the soft segments. The triblock copolymers showed very high elongation at break up to approximately 2800% and elastic properties. The corresponding d ‐triblock copolymers, PDLA‐block‐P(CL‐stat‐DLLA)‐block‐PDLAs (PDLA = poly(d ‐lactide)) were also prepared with the same procedure using d ‐lactide in place of l ‐lactide. When the PLLA‐block‐P(CL‐stat‐DLLA)‐block‐PLLA was blended with PDLA‐block‐P(CL‐stat‐DLLA)‐block‐PDLA, stereocomplex crystals were formed to enhance their Tm as well as tensile properties. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 489–495 相似文献
6.
Ren‐Shen Lee Jen‐Ming Yang 《Journal of polymer science. Part A, Polymer chemistry》2000,38(13):2449-2455
The synthesis of hydroxyproline‐based telechelic prepolymers by the condensation polymerization of trans‐4‐hydroxy‐N‐benzyloxycarbonyl‐L ‐proline methyl ester was investigated. All the polymerizations were carried out in the melt with stannous octoate as the catalyst and with different diols. The products were characterized by differential scanning calorimetry, proton nuclear magnetic resonance, infrared spectrophotometry, and inherent viscosity (ηinh). According to the analytic results, the ηinh value of the prepolymers depended on the kind and amount of diols that were added. With an increase in the 1,6‐hexanediol feed from 2 to 10 mol %, there was a decrease in ηinh from 0.78 to 0.41 along with a decrease in the glass‐transition temperature (Tg ) from 63 to 42 °C. When 2 mol % of different kinds of diols were used, ηinh ranged from 0.78 to 0.21, and Tg varied from 70 to 43 °C. These new prepolymers could be linked to poly(ester‐urethane) by the chain extender 1,6‐hexamethylene diisocyanate. The poly(ester‐urethane) was amorphous, and the Tg was 76 °C. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2449–2455, 2000 相似文献
7.
Deivasagayam Dakshinamoorthy Frédéric Peruch 《Journal of polymer science. Part A, Polymer chemistry》2012,50(11):2161-2171
A series of di‐ and triblock copolymers [poly(L ‐lactide‐b‐ε‐caprolactone), poly(D,L ‐lactide‐b‐ε‐caprolactone), poly(ε‐caprolactone‐b‐L ‐lactide), and poly(ε‐caprolactone‐b‐L ‐lactide‐b‐ε‐caprolactone)] have been synthesized successfully by sequential ring‐opening polymerization of ε‐caprolactone (ε‐CL) and lactide (LA) either by initiating PCL block growth with living PLA chain end or vice versa using titanium complexes supported by aminodiol ligands as initiators. Poly(trimethylene carbonate‐b‐ε‐caprolactone) was also prepared. A series of random copolymers with different comonomer composition were also synthesized in solution and bulk of ε‐CL and D,L ‐lactide. The chemical composition and microstructure of the copolymers suggest a random distribution with short average sequence length of both the LA and ε‐CL. Transesterification reactions played a key role in the redistribution of monomer sequence and the chain microstructures. Differential scanning calorimetry analysis of the copolymer also evidenced the random structure of the copolymer with a unique Tg. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
8.
Chang‐Ming Dong Kun‐Yuan Qiu Zhong‐Wei Gu Xin‐De Feng 《Journal of polymer science. Part A, Polymer chemistry》2000,38(23):4179-4184
D ,L ‐3‐Methylglycolide (MG) was synthesized via two step reactions with a good yield (42%). It was successfully polymerized in bulk with stannous octoate as a catalyst at 110 °C. The effects of the polymerization time and catalyst concentration on the molecular weight and monomer conversion were studied. Poly(D ,L ‐lactic acid‐co‐glycolic acid) (D ,L ‐PLGA50; 50/50 mol/mol) copolymers were successfully synthesized from the homopolymerization of MG with high polymerization rates and high monomer conversions under moderate polymerization conditions. 1H NMR spectroscopy indicated that the bulk ring‐opening polymerization of MG conformed to the coordination–insertion mechanism. 13C NMR spectra of D ,L ‐PLGA50 copolymers obtained under different experimental conditions revealed that the copolymers had alternating structures of lactyl and glycolyl. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4179–4184, 2000 相似文献
9.
Kazuhiko Hashimoto Hiroshi Saito Ryo Ohsawa 《Journal of polymer science. Part A, Polymer chemistry》2006,44(16):4895-4903
Two kinds of new glycopolymers, (P(VB‐1‐GlcaH‐co‐AAm), 9 ) and (P(VB‐1‐Glco‐co‐AAm), 10 ), were synthesized through the radical copolymerization of styrene derivatives bearing pendant D ‐glucaric and D ‐gluconic moieties, N‐(p‐vinylbenzyl)‐1‐D ‐glucaramide (VB‐1‐GlcaH, 7 ), and N‐(p‐vinylbenzyl)‐D ‐gluconamide (VB‐1‐Glco, 8 ), with acrylamide (AAm). Glycopolymer 9 bearing the pendant glucaric moiety at the first position inhibited the hydrolysis of a model compound for xenobiotics‐β‐glucuronide conjugates, p‐nitrophenyl β‐D ‐glucuronide, uncompetitively, in contrast to the competitive inhibition in the presence of the corresponding isomeric glycopolymer bearing the pendant D ‐glucaric unit at the sixth position (P(VB‐6‐GlcaH‐co‐AAm), 3 ) reported in our previous article. On the other hand, another copolymer 10 bearing the gluconic moiety was found not to inhibit the hydrolysis as well as the corresponding copolymer bearing pendant gulonic unit (P(VB‐6‐Glco‐co‐AAm), 4 ). These results indicate that the hydrolysis is influenced not only by existence of pendant carboxyl units but also by the direction on the linkage of the glyco‐units to the polymer frame. Therefore the configurational position of hydroxy groups in pendant glyco‐units in macromolecular inhibitors may be essential for the interaction with β‐glucuronidase. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4895–4903, 2006 相似文献
10.
Amornrat Lertworasirikul Nu‐orn Choothong Hiroaki Yoshida Michiya Matsusaki Toshiyuki Kida Apirat Laobuthee Mitsuru Akashi 《Journal of polymer science. Part A, Polymer chemistry》2012,50(23):4823-4828
The thermosensitivity of biodegradable and non‐toxic amphiphilic polymer derived from a naturally occurring polypeptide and a derivative of amino acid was first reported. The amphiphilic polymer consisted of poly(γ‐glutamic acid) (γ‐PGA) as a hydrophilic backbone, and L ‐phenylalanine ethyl ester (L ‐PAE) as a hydrophobic branch. Poly(γ‐glutamic acid)‐graft‐L ‐phenylalanine (γ‐PGA‐graft‐L ‐PAE) with grafting degrees of 7–49% were prepared by varying the content of a water‐soluble carbodiimide (WSC). γ‐PGA‐graft‐L ‐PAE with a grafting degree of 49% exhibited thermoresponsive phase transition behavior in an aqueous solution at around 80°C. The copolymers with grafting degrees in the range of 30–49% showed thermoresponsive properties in NaCl solution. A clouding temperature (Tcloud) could be adjusted by changing the polymer concentration and/or NaCl concentration. The thermoresponsive behavior was reversible. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
11.
Chang‐Ming Dong Kun‐Yuan Qiu Zhong‐Wei Gu Xin‐De Feng 《Journal of polymer science. Part A, Polymer chemistry》2002,40(3):409-415
Two types of three‐arm and four‐arm, star‐shaped poly(D,L ‐lactic acid‐alt‐glycolic acid)‐b‐poly(L ‐lactic acid) (D,L ‐PLGA50‐b‐PLLA) were successfully synthesized via the sequential ring‐opening polymerization of D,L ‐3‐methylglycolide (MG) and L ‐lactide (L ‐LA) with a multifunctional initiator, such as trimethylolpropane and pentaerythritol, and stannous octoate (SnOct2) as a catalyst. Star‐shaped, hydroxy‐terminated poly(D,L ‐lactic acid‐alt‐glycolic acid) (D,L ‐PLGA50) obtained from the polymerization of MG was used as a macroinitiator to initiate the block polymerization of L ‐LA with the SnOct2 catalyst in bulk at 130 °C. For the polymerization of L ‐LA with the three‐arm, star‐shaped D,L ‐PLGA50 macroinitiator (number‐average molecular weight = 6800) and the SnOct2 catalyst, the molecular weight of the resulting D,L ‐PLGA50‐b‐PLLA polymer linearly increased from 12,600 to 27,400 with the increasing molar ratio (1:1 to 3:1) of L ‐LA to MG, and the molecular weight distribution was rather narrow (weight‐average molecular weight/number‐average molecular weight = 1.09–1.15). The 1H NMR spectrum of the D,L ‐PLGA50‐b‐PLLA block copolymer showed that the molecular weight and unit composition of the block copolymer were controlled by the molar ratio of L ‐LA to the macroinitiator. The 13C NMR spectrum of the block copolymer clearly showed its diblock structures, that is, D,L ‐PLGA50 as the first block and poly(L ‐lactic acid) as the second block. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 409–415, 2002 相似文献
12.
Gérald Lopez Noureddine Ajellal Alagappan Thenappan Bruno Ameduri 《Journal of polymer science. Part A, Polymer chemistry》2014,52(12):1714-1720
The radical copolymerization of chlorotrifluoroethylene (CTFE) with 3,3,4,4‐tetrafluoro‐4‐bromobut‐1‐ene (BTFB) initiated by tert‐butylperoxypivalate is presented. The microstructures of the obtained copolymers are determined by means of NMR spectroscopies and elemental analysis and show that random copolymers were obtained. A wide range of poly(CTFE‐co‐BTFB) copolymers is synthesized, containing from 17 to 89 mol % of CTFE. In all the cases, CTFE is the less reactive of both comonomers. Td10% values, ranging from 163 up to 359 °C, are dependent on the BTFB content. These variations of thermal property are attributed to the increase in the number of C‐H and C‐Br bonds breakdown when the BTFB molar percentage in the copolymer is higher. Tg values range from 19 to 39 °C and a decreasing trend is observed when increasing the amount of BTFB in the copolymer. This observation arises from the higher flexibility of the copolymer when increasing the number of fluorobrominated lateral chains. These original fluoropolymers bearing reactive pendant bromo groups are suitable candidates for various applications. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1714–1720 相似文献
13.
J. Xu Y. Z. Meng S. J. Wang A. S. Hay 《Journal of polymer science. Part A, Polymer chemistry》2006,44(10):3328-3335
A series of novel soluble pyridazinone‐ or pyridazine‐containing poly(arylene ether)s were prepared by a polycondensation reaction. The pyridazinone monomer, 6‐(4‐hydroxyphenyl)pyridazin‐3(2H)‐one ( 1 ), was synthesized from the corresponding acetophenone and glyoxylic acid in a simple one‐pot reaction. The pyridazinone monomer was successfully copolymerized with bisphenol A (BPA) or 1,2‐dihydro‐4‐(4‐hydroxyphenyl)phthalazin‐1(2H)‐one (DHPZ) and bis(4‐fluorophenyl)sulfone to form high‐molecular‐weight polymers. The copolymers had inherent viscosities of 0.5–0.9 dL/g. The glass‐transition temperatures (Tg's) of the copolymers synthesized with BPA increased with increasing content of the pyridazinone monomer. The Tg's of the copolymers synthesized from DHPZ with different pyridazinone contents were similar to those of the two homopolymers. The homopolymers showed Tg's from 202 to 291 °C by differential scanning calorimetry. The 5% weight loss temperatures in nitrogen measured by thermogravimetric analysis were in the range of 411–500 °C. 4‐(6‐Chloropyridazin‐3‐yl)phenol ( 2 ) was synthesized from 1 via a simple one‐pot reaction. 2 was copolymerized with 4,4′‐isopropylidenediphenol and bis(4‐fluorophenyl)sulfone to form high‐Tg polymers. The copolymers with less than 80 mol % pyridazinone or chloropyridazine monomers were soluble in chlorinated solvents such as chloroform. The copolymers with higher pyridazinone contents and homopolymers were not soluble in chlorinated solvents but were still soluble in dipolar aprotic solvents such as N‐methylpyrrolidinone. The soluble polymers could be cast into flexible films from solution. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3328–3335, 2006 相似文献
14.
Chin‐Ti Chen Te‐Shao Hsu Ru‐Jong Jeng Hsiu‐Chih Yeh 《Journal of polymer science. Part A, Polymer chemistry》2000,38(3):498-503
Polyimide copolymers containing 2,2′‐bipyridine were synthesized and characterized. The glass‐transition temperatures (Tg's) of the polymers ranged from 260 to 300 °C. In contrast to most known organic chromophore‐containing polyimides, the polyimide copolymers in this study showed elevated Tg's (270–320 °C) after coordination with nickel malenonitriledithiolate inorganic chromophores. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 498–503, 2000 相似文献
15.
Noureddine Ajellal Christophe M. Thomas Jean‐François Carpentier 《Journal of polymer science. Part A, Polymer chemistry》2009,47(12):3177-3189
The copolymerization of racemic β‐butyrolactone (rac‐BLMe) with racemic “allyl‐β‐butyrolactone” (rac‐BLallyl) in toluene, catalyzed by the discrete amino‐alkoxy‐bis(phenolate) yttrium‐amido complex 1 , gave new poly(β‐hydroxyalkanoate)s with unsaturated side chains. The poly(BLMe‐co‐BLallyl) copolymers produced have a highly syndiotactic backbone structure (Pr = 0.80–0.84) with a random enchainment of monomer units, as evidenced by 13C NMR, and high molecular weight (Mn up to 58,000 g mol?1) with a narrow polydispersity (Mw/Mn = 1.07–1.37), as determined by GPC. The comonomer incorporation (5–50 mol % rac‐BLallyl) was a linear function of the feed ratio. The pendant vinyl bond of the side‐chains in those poly(BLMe‐co‐BLallyl) copolymers allowed the effective introduction of hydroxy or epoxy groups via dihydroxylation, hydroboration‐oxidation or epoxidation reactions. NMR studies indicated that all of these transformations proceed in an essentially quantitative conversion and do not affect the macromolecular architecture. Some thermal properties (Tm, ΔHm, Tg) of the prepared polymers have been also evaluated. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3177–3189, 2009 相似文献
16.
Daniel J. Klein Joseph E. Korleski Frank W. Harris 《Journal of polymer science. Part A, Polymer chemistry》2001,39(12):2037-2042
A self‐polymerizable quinoxaline monomer (A‐B) has been synthesized and polymerized via aromatic nucleophilic substitution reactions. An isomeric mixture of self‐polymerizable quinoxaline monomers—2‐(4‐hydroxyphenyl)‐3‐phenyl‐6‐fluoroquinoxaline and 3‐(4‐hydroxyphenyl)‐2‐phenyl‐6‐fluoroquinoxaline—was polymerized in N‐methyl‐2‐pyrrolidinone (NMP) to afford high molecular weight polyphenylquinoxaline (PPQ) with intrinsic viscosities up to 1.91 dL/g and a glass‐transition temperature (Tg) of 251 °C. A series of comonomers was polymerized with A‐B to form PPQ/polysulfone (PS), PPQ/polyetherether ketone (PEEK), and PPQ/polyethersulfone (PES) copolymers. The copolymers readily obtained high intrinsic viscosities when fluorine was displaced in NMP under reflux. However, single‐electron transfer (SET) side reactions, which limit molecular weight, played a more dominant role when chlorine was displaced instead of fluorine. SET side reactions were minimized in the synthesis of PPQ/PS copolymers through mild polymerization conditions in NMP for longer polymerization times. Thus, the Tg's of PES (Tg = 220 °C), PEEK (Tg = 145 °C), and PS (Tg = 195 °C) were raised through the incorporation of quinoxaline units into the polymer. Copolymers with high intrinsic viscosities resulted in all cases, except in the case of PPQ/PEEK copolymers when 4,4′‐dichlorobenzophenone was the comonomer. © 2001 John Wiley & Sons, Inc. J Polym Sci A Part A: Polym Chem 39: 2037–2042, 2001 相似文献
17.
Jamie M. Messman Robson F. Storey 《Journal of polymer science. Part A, Polymer chemistry》2006,44(23):6817-6835
Ethylene glycol (EG) initiated, hydroxyl‐telechelic poly(L ‐lactide) (PLLA) was employed as a macroinitiator in the presence of a stannous octoate catalyst in the ring‐opening polymerization of 5‐methyl‐5‐benzyloxycarbonyl‐1,3‐dioxan‐2‐one (MBC) with the goal of creating A–B–A‐type block copolymers having polycarbonate outer blocks and a polyester center block. Because of transesterification reactions involving the PLLA block, multiblock copolymers of the A–(B–A)n–B–A type were actually obtained, where A is poly(5‐methyl‐5‐benzyloxycarbonyl‐1,3‐dioxan‐2‐one), B is PLLA, and n is greater than 0. 1H and 13C NMR spectroscopy of the product copolymers yielded evidence of the multiblock structure and provided the lactide sequence length. For a PLLA macroinitiator with a number‐average molecular weight of 2500 g/mol, the product block copolymer had an n value of 0.8 and an average lactide sequence length (consecutive C6H8O4 units uninterrupted by either an EG or MBC unit) of 6.1. For a PLLA macroinitiator with a number‐average molecular weight of 14,400 g/mol, n was 18, and the average lactide sequence length was 5.0. Additional evidence of the block copolymer architecture was revealed through the retention of PLLA crystallinity as measured by differential scanning calorimetry and wide‐angle X‐ray diffraction. Multiblock copolymers with PLLA crystallinity could be achieved only with isolated PLLA macroinitiators; sequential addition of MBC to high‐conversion L ‐lactide polymerizations resulted in excessive randomization, presumably because of residual L ‐lactide monomer. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6817–6835, 2006 相似文献
18.
Kazuhiko Hashimoto Ryo Ohsawa Naohiro Imai Masahiko Okada 《Journal of polymer science. Part A, Polymer chemistry》1999,37(3):303-312
Two kinds of novel vinyl monomers having D ‐glucaric moieties leading to a new type of glycopolymeric inhibitors of β‐glucuronidase, N‐p‐vinylbenzyl‐6‐D ‐glucaramide (6 ) and potassium N‐p‐vinylbenzyl‐6‐D ‐glucaramid‐1‐ate (8 ), were synthesized by the reaction of D ‐glucaro‐6,3‐lactone (3 ) with p‐vinylbenzylamine (5 ) with no catalyst, and the subsequent treatment of the reaction mixture with acetic anhydride and potassium hydroxide aqueous solution, respectively. The radical copolymerization of 8 with acrylamide in various feed ratios at 60°C in 0.1 N potassium chloride aqueous solution gave water‐soluble copolymers (9 ) composed of a synthetic polymeric main chain and many pendant D ‐glucaric chains. The resulting glycopolymers (9 ) were found to inhibit the activity of β‐glucuronidase strongly through a model reaction with p‐nitrophenyl β‐D ‐glucuronide (10 ) in acetic buffer solution (pH 4.7). © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 303–312, 1999 相似文献
19.
The phase behavior of ternary poly‐(2‐vinylpyridine) (P2VPy)/poly‐(N‐vinyl‐2‐pyrrolidone) (PVP)/bis‐(4‐hydroxyphenyl)methane (BHPM) blends was studied. Fourier transform infrared spectroscopic examinations demonstrated that BHPM interacts with P2VPy and PVP through hydrogen‐bonding interactions. The addition of a sufficiently large amount of BHPM transformed an opaque blend with two glass‐transition temperatures (Tg's) to a transparent single‐Tg blend. Scanning electron microscopic studies showed that the transparent single‐Tg blend is micro‐phase‐separated at a scale of about 30 nm. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1815–1823, 2001 相似文献
20.
Der‐Jang Liaw Jun‐Jang Hsu Been‐Yang Liaw 《Journal of polymer science. Part A, Polymer chemistry》2001,39(17):2951-2956
A new cardo diacid chloride, 1,1‐bis‐[4‐(4‐chlorocarboxyphenoxy)phenyl]‐4‐tert‐butylcyclohexane ( 4 ), was synthesized from 1,1‐bis‐[4‐(4‐carboxyphenoxy)phenyl]‐4‐tert‐butylcyclohexane in refluxing thionyl chloride. Subsequently, various new polyesters were prepared from 4 with various bisphenols by solution polycondensation in nitrobenzene using pyridine as a hydrogen chloride quencher at 150 °C. These polyesters were produced with inherent viscosities of 0.32–0.50 dL · g?1. Most of these polyesters exhibited excellent solubility in a variety of solvents such as N,N‐dimethylformamide, tetrahydrofuran, tetrachloroethane, dimethyl sulfoxide, N,N‐dimethylacetamide, N‐methyl‐2‐pyrrolidinone, m‐cresol, o‐chlorophenol, and chloroform. These polymers showed glass‐transition temperatures (Tg's) between 144 and 197 °C. The polymer containing the adamantane group exhibited the highest Tg value. The 10% weight loss temperatures of the polyesters, measured by thermogravimetric analysis, were found to be in the range of 426–451 °C in nitrogen. These cardo polyesters exhibited higher Tg's and better solubility than bisphenol A‐based polyesters. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2951–2956, 2001 相似文献