Syntheses and antitumor activities of medium molecular weight polymers containing 5-fluorouracil

The new monomer α-ethoxy-3,6-endo-methylene-1,2,3,6-tetrahydrophthaloyl-5-fluorouracil (EMTFU) was synthesized from 5-fluorouracil (5-FU) and α-ethoxy-3,6-endo-methylene-1,2,3,6-tetrahydrophthaloyl chloride (EMTC). Poly(α-ethoxy-3,6-endomethylene-1,2,3,6-tetrahydrophthaloyl-5-fluorouracil) [poly(EMTFU)], poly(α-ethoxy-3,6-endo-methylene-1,2,3,6-tetrahydrophthaloyl-5-fluorouracil-co-acrylic acid) [poly(EMTFU-co-AA)], and poly(α-ethoxy-3,6-endomethylene-1,2,3,6-tetrahydrophthaloyl-5-fluorouracil-co-vinyl acetate) [poly(EMTFU-co-VAc)] were synthesized by photopolymerizations using 2,2-dimethoxy-2-phenylacetophenone (DMP) as the photoinitiator. The synthesized EMTFU and its polymers were identified by Fourier transfer infrared (FT-IR), ¹H nuclear magnetic resonance (NMR), and ¹³C-NMR spectroscopies. The contents of EMTFU in poly(EMTFU-co-AA) and poly(EMTFU-co-VAc) determined by elemental analysis were 46 and 70 mol %, respectively. The number average molecular weights of the synthesized polymers determined by gel permeation chromatography (GPC) were in range of 17,200–20,900. The in vitro cytotoxicities of samples were evaluated with mouse mammary carcinoma (FM3A), mouse leukemia (P388), and human histiocytic lymphoma (U937) as cancer cell lines and AC2F as a normal cell line. The cytotoxicities of 5-FU and synthesized samples against cancer cell lines increased in following orders: 5-FU ≈ EMTFU > poly(EMTFU-co-AA) > poly(EMTFU) > poly(EMTFU-co-VAc). The in vivo antitumor activities of the synthesized samples against mice bearing the sarcoma 180 tumor cell line were evaluated. The in vivo antitumor activities of EMTFU and its polymers were greater than those of 5-FU at a dosage of 80 mg/kg. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2985–2992, 1998     

Syntheses and biological activities of α-methoxy-3,6-endo-methylene-1,2,3,6-tetrahydrophthaloyl-5-fluorouracil and its polymers

The new monomer, α-methoxy-3,6-endo-methylene-1,2,3,6-tetrahydrophthaloyl-5-fluorouracil (MMTFU), was synthesized from 5-fluorouracil (5-FU) and α-methoxy-3,6-endo-methylene-1,2,3,6-tetrahydrophthaloyl chloride (MMTC). Poly(α-methoxy-3,6-endo-methylene-1,2,3,6-tetrahydrophthaloyl-5-fluorouracil) [poly(MMTFU)], poly(α-methoxy-3,6-endo-methylene-1,2,3,6-tetrahydrophthaloyl-5-fluorouracil-co-acrylicco-AA), and poly(α-methoxy-3,6-endo-methylene-1,2,3,6-tetrahydrophthaloyl-5-fluorouracil-co-vinyl acetate) [poly(MMTFU-co-VAc)] were synthesized by photopolymerizations using 2,2-dimethoxy-2-phenylacetophenone (DMP) as the photoinitiator. The synthesized MMTFU and the polymers were identified by FT-IR, ¹H-NMR, and ¹³C-NMR spectroscopies. The contents of MMTFU in poly(MMTFU-co-AA) and poly(MMTFU-co-VAc) determined by elemental analysis were 63 and 57 mol %, respectively. The number average molecular weights and polydispersity indices of synthesized polymers determined with GPC were in range of 7,700–19,100 and 1.6–2.7. The in vitro cytotoxicities of samples were evaluated with mouse mammary carcinoma (FM3A), mouse leukemia (P388), and human histiocytic lymphoma (U937) as cancer cell lines and mouse liver cells (AC2F) as a normal cell line. The cytotoxicities of 5-FU and synthesized samples against cancer cell lines increased in following orders: 5-FU > MMTFU > poly(MMTFU) > poly(MMTFU-co-AA) > poly(MMTFU-co-VAc). The in vivo antitumor activities of the synthesized samples against mice bearing the sarcoma 180 tumor cell line were evaluated. The in vivo antitumor activities of the polymers were greater than that of 5-FU at a dose of 80 mg/kg. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1625–1632, 1998     

Syntheses and antitumor activities of medium molecular weight polymers containing α-ethoxy-exo-3,6-epoxy-1,2,3,6-tetrahydrophthaloyl-5-fluorouracil

The new monomer, α-ethoxy-exo-3,6-epoxy-1,2,3,6-tetrahydrophthaloyl-5-fluorouracil (EETFU), was synthesized from 5-fluorouracil (5-FU) and α-ethoxy-exo-3,6-epoxy-1,2,3,6-tetrahydrophthaloyl chloride. Its homopolymer and copolymers with acrylic acid (AA) and vinyl acetate (VAc) were synthesized by photopolymerizations using 2,2-dimethoxy-2-phenylaceto-phenone. The synthesized samples were characterized by FT-IR, ¹H-NMR and ¹³C-NMR spectroscopes, elemental analysis, and gel permeation chromatography. The EETFU contents in poly(EETFU-co-AA) and poly(EETFU-co-VAc) were 40 and 37 mol %, respectively. The number average molecular weights were in range from 8,400 to 10,300. The in vitro cytotoxicities of synthesized samples were evaluated against mouse mammary carcinoma (FM3A), mouse leukemia (P388), and human histiocytic lymphoma (U937) as cancer cell lines and mouse liver cells (AC2F) as a normal cell line. The range of IC₅₀ values obtained from the in vitro test for synthesized samples were 0.03–0.16 µg/mL against cancer cell lines. The in vitro cytotoxicities of polymers were beter than 5-FU. The in vivo antitumor activities of synthesized monomer and polymers were also investigated by mice bearing the sarcoma 180 tumor cells. The in vivo antitumor activities of the synthesized monomer and polymers were greater than those of 5-FU at corresponding dosage concentrations. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2619–2627, 1999     

Syntheses and antitumor activities of monomer and medium molecular weight polymers. III. 3,6-endo-methylene-1,2,3,6-tetrahydrophthalimidopropanoyl-5-fluorouracil and its polymers

The new monomer, 3,6-endo-methylene-1,2,3,6-tetrahydrophthalimidopropanoyl-5-fluorouracil (ETPFU), was synthesized by the reaction of 5-fluorouracil (5-FU) and 3,6-endo-methylene-1,2,3,6-tetrahydrophthalimidopropanoyl chloride (ETPC). The homopolymer of ETPFU and its copolymers with acrylic acid (AA) and vinyl acetate (VAc) were prepared by photopolymerizations. The synthesized ETPFU and polymers were identified by Fourier transfer infrared (FTIR), ¹H nuclear magnetic resonance (NMR), and ¹³C-NMR spectroscopies. The contents of ETPFU units in poly(ETPFU-co-AA) and poly(ETPFU-co-VAc) were 26 and 32 mol %, respectively. The number average molecular weights of the synthesized polymers determined by gel permeation chromatography (GPC) were in range from 8,800 to 10,700. The in vitro cytotoxicities of the samples were evaluated with mouse mammary carcinoma (FM3A), mouse leukemia (P388), and human histiocytic lymphoma (U937) as a cancer cell line and mouse liver cells (AC2F) as a normal cell line. The in vivo antitumor activities of polymers against Balb/c mice bearing the sarcoma 180 tumor cells were greater than those of 5-FU at all doses tested. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2113–2120, 1999     

Synthesis and biological activity of medium molecular weight polymers of camptothecin

A new monomer, 3,6-endo-methylene-1,2,3,6-tetrahydrophthalimidohexanoylcamptothecin (ETHCPT) was synthesized from 3,6-endo-methylene-1,2,3,6-tetrahydrophthalimidohexanoic acid. Its homopolymer and copolymer with acrylic acid (AA) were synthesized and spectroscopically characterized. The ETHCPT content in poly(ETHCPT-co-AA) obtained by elemental analysis was 37 wt.%. The number-average molecular weights of the polymers determined by gel permeation chromatography were as follows: M_n=9700 for poly(ETHCPT), for poly(ETHCPT-co-AA). The IC₅₀ value of ETHCPT and its polymers against cancer cells was much larger than that of CPT. The in vivo antitumor activity of all polymers in Balb/C mice bearing the sarcoma 180 tumor cell line was greater than that of CPT at a dose of 100 mg/kg.     

Syntheses,antitumor activities,and antiangiogenesis of exo‐3,6‐epoxy‐1,2,3,6‐tetrahydrophthalimidoethanoyl‐ 5‐fluorouracil and its polymers

A new monomer, exo‐3,6‐epoxy‐1,2,3,6‐tetrahydrophthalimidoethanoyl‐5‐fluorouracil (ETFU), was synthesized by the reaction of exo‐3,6‐epoxy‐1,2,3,6‐tetrahydrophthalimidoethanoyl chloride (ETPC) and 5‐fluorouracil (5‐FU). The homopolymer of ETFU and its copolymers with acrylic acid (AA) and vinyl acetate (VAc) were prepared via photopolymerizations with 2,2‐dimethoxy‐2‐phenylacetophenone at 25 °C for 48 h. The structures of the synthesized monomer and polymers were identified by Fourier transform infrared, ¹H NMR, and ¹³C NMR spectroscopy and elemental analysis. The ETFU contents in poly(ETFU‐co‐AA) and poly(ETFU‐co‐VAc) were 26 mol % and 26 mol %, respectively. The number‐average molecular weights of the polymers, as determined by gel permeation chromatography, ranged from 5600 to 17,000. The in vitro cytotoxicities of 5‐FU and the synthesized samples against mouse mammary carcinoma and human histiocytic lymphoma cancer cell lines increased in the following order: ETFU > 5‐FU > poly(ETFU‐co‐AA) > poly(ETFU) > poly(ETFU‐co‐VAc). The in vivo antitumor activities of the polymers against Balb/C mice bearing the sarcoma 180 tumor cells were greater than those of 5‐FU at all doses tested. The inhibitions of the samples for SV40 DNA replication and antiangiogenesis were much greater than the inhibition of the control. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4272–4281, 2000     

Syntheses and antitumor activities of polymers containing amino acid and 5‐fluorouracil moieties

The new monomer, 3,6‐endo‐methylene‐1,2,3,6‐tetrahydrophthalimidoethanoyl‐5‐fluorouracil (ETEFU), was synthesized from 5‐fluorouracil (5‐FU) and 3,6‐endo‐methylene‐1,2,3,6‐tetrahydophthalimidoethanoyl chloride (ETEC). Its homopolymer and copolymers with acrylic acid (AA) and vinyl acetate (VAc) were prepared by photopolymerization reactions using 2,2‐dimethoxy‐2‐phenylacetophenone (DMP) as the photoinitiator. The synthesized ETEFU and polymers were identified by FT‐IR, ¹H‐NMR, and ¹³C‐NMR spectra. The contents of ETEFU units in poly(ETEFU‐co‐AA) and poly(ETEFU‐co‐VAc) were 20 and 17 mol%, respectively. The number‐average molecular weights of the synthesized polymers determined by gel permeation chromatography (GPC) were 4,600 to 10,700 g mol⁻¹. In vitro cytotoxicities of samples were evaluated with cancer cell lines [mouse mammary carcinoma (FM3A), mouse leukemia (P388), and human histiocytic lymphoma (U937)] and a normal cell line [mouse liver cells (AC2F)]. Cytotoxicities of 5‐FU and synthesized samples against the cancer cell lines were ranked as follows: ETEFU > poly(ETEFU) > 5‐FU > poly(ETEFU‐co‐AA) > poly(ETEFU‐co‐VAc). The in vivo antitumor activities of poly(ETEFU) and poly(ETEFU‐co‐AA) against Balb/C mice bearing the sarcoma 180 tumor cells were greater than those of 5‐FU at all doses except for the activity of poly(ETEFU) at 0.8 mg/kg. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1589–1595, 1999     

Synthesis and in vitro antitumor activity of phthalimide polymers containing podophyllotoxin

Polymer-linked PT (podophyllotoxin) conjugates have been designed to improve the therapeutic efficacy of PT. A new PT-conjugate, 3,6-endo-methylene-1,2,3,6-tetrahydrophthalimido-acetamidoglycinylglycine podophyllotoxin ester (ETPA-gly-gly-PT), was synthesized by covalently coupling its hydroxyl group onto the phthalimido monomer through a glycine-glycine-glycine spacer. Its homo- and copolymer with acrylic acid (AA) were prepared by photopolymerization using 2,2-dimethoxy-2-phenylacetophenone (DMP) as a photoinitiator. ETPA-gly-gly-PT and its polymers were characterized by IR and proton NMR spectra. The ETPA-gly-gly-PT content in the copolymer obtained by elemental analysis was 44 wt%. The number-average molecular weights of the polymers determined by gel permeation chromatography were as follows: M_n = 13,500 for poly(ETPA-gly-gly-PT), M_n = 17,000 for poly(ETPA-gly-gly-PT-co-AA). The in vitro antitumor activity of these conjugates and polymers were determined and used to evaluate the potential applications in antitumor drugs. The IC₅₀ values indicated that the synthesized ETPA-gly-gly-PT and its polymers against cancer cells were much better inhibitors than PT.     

New amino acid based biodegradable poly(ester amide)s via bis-azlactone chemistry

Abstract

Three new classes of the amino acid based biodegradable (AABB) polymers were synthesized via step growth polymerization of bis-azlactones and amino acid based diamine-diesters with activated fatty diester and alkylenediamine: a) poly(ester amide)s (PEAs) were obtained by polymerization of bis-azlactones with diamine-diesters, b) hydrophobically modified co-poly(ester amide)s (co-PEAs) were synthesized by copolymerization of activated fatty diacid diester and bis-azlactones with diamine-diesters, and c) poly(ester amide-co-amide)s (PEA-co-PAs) were obtained by copolymerization of alkylene diamine and diamine-diesters with bis-azlactones. The new poly(ester amide)s showed relatively low-molecular-weights (M_w within 2,800–19,600?Da, GPC in DMF), whereas the new co-poly(ester amide)s and poly(ester amide-co-amide)s exhibited high-molecular-weights (M_w within 40–100?kDa) leading to good mechanical properties. Incorporation of the bis-azlactone fragments into the poly(ester amide)s backbone increased hydrophobicity and thermal stability, whereas incorporation of diamine-diester units into the backbone of the bis-azlactone based polyamides rendered them biodegradable. Synthesized AABB polymers are potential candidates for constructing resorbable surgical and pharmaceutical devices.     

New Approach to Determine the Phase Transition Temperature,Cloud Point,of Thermoresponsive Polymers

In this study, a novel method to determine the cloud point temperature variation in aqueous solutions of thermoresponsive homo- and copolymers was developed. Poly(N-vinylcaprolactam) (PVCL) and triblock copolymers of poly(t-butyl acrylate-co-acrylic acid)-b-poly(N-vinylcaprolactam)-b-(t-butyl acrylate-co-acrylic acid) (P[(tBA-co-AA)-b-PVCL-b-P(tBA-co-AA)] were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization and used as models. The incorporation of AA units (hydrophilic segments) into the polymeric chain of PVCL influenced the phase transition, increasing the cloud point temperature of the final copolymer. The cloud point temperatures of the PVCL and the triblock copolymer P(tBA-co-AA)-b-PVCL-b-P(tBA-co-AA) were determined by measuring the transmittance of aqueous solutions of the polymers in a Turbiscan Lab instrument in the range of 29 to 40 C. This is the first study in which Turbiscan Lab is used to determine the cloud point temperature.     

Study of Phase Separation of Poly(N-isopropylacrylamide-co-styrene) Aqueous Solutions with Rayleigh Scattering Technique

A thermally sensitive copolymer, poly(N‐isopropylacrylamide‐co‐styrene) [P(NIPAM‐co‐St)] (M_n?9.5×10⁵ g/mol and M_w/M_n?1.51) was synthesized by soap‐free emulsion polymerization. The phase separation of the copolymer in water was investigated by Rayleigh scattering (RS) technique. The RS spectra revealed the transition of molecular conformation and the aggregation of molecular chains in the course of phase separation. The coil‐to‐globule and globule‐to‐coil transitions of P(NIPAM‐co‐St) chains were found in one heating‐and‐cooling cycle. By means of Avrami formula, apparent activation energy of phase separation of P(NIPAM‐co‐St) aqueous solutions was estimated. Moreover, a model was proposed to describe the phase separation process.     

Novel,biodegradable, functional poly(ester‐carbonate)s by copolymerization of trans‐4‐hydroxy‐L‐proline with cyclic carbonate bearing a pendent carboxylic group

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 (M_n) and molecular weight distribution (M_w/M_n) 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 (M_n = 6000–14,700 g mol^?1) with reasonable molecular weight distributions (M_w/M_n = 1.11–2.23). The values of the glass‐transition temperature (T_g) of the copolymers depended on the molar fractions of cyclic carbonate. When the MBC content decreased from 76 to 12 mol %, the T_g increased from 16 to 48 °C. The relationship between the poly(N‐CBz‐Hpr‐co‐MBC) T_g 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 M_n and M_w/M_n. 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     

Syntheses,antitumor activities,and antiangiogenesis of a monomer and its medium molecular weight polymers: Maleimidoethanoyl‐5‐fluorouracil and its polymers

A new monomer, maleimidoethanoyl‐5‐fluorouracil (MIEFU), was synthesized by the reaction of maleimidoethanoyl chloride and 5‐fluorouracil (5‐FU). The homopolymer of MIEFU and its copolymers with acrylic acid (AA) or vinyl acetate (VAc) were prepared by photopolymerizations with 2,2‐dimethoxy‐2‐phenylacetophenone as an initiator at 25 °C for 48 h. The structures of the synthesized monomer and polymers were identified by Fourier transform infrared, ¹H NMR, and ¹³C NMR spectroscopies and elemental analysis. The contents of the MIEFU units in poly(MIEFU‐co‐AA) and poly(MIEFU‐co‐VAc) were 18 and 30 mol %, respectively. The number‐average molecular weights of the synthesized polymers, as determined by gel permeation chromatography, ranged from 4900 to 9800. The in vitro cytotoxicities of the samples against mouse mammary carcinoma (FM3A), mouse leukemia (P388), and human histiocytic lymphoma (U937) cancer cell lines decreased in the following order: 5‐FU ≥ MIEFU > poly(MIEFU) > poly(MIEFU‐co‐AA) > poly(MIEFU‐co‐VAc). The in vivo antitumor activities of the polymers against Balb/C mice bearing the sarcoma 180 tumor cells were greater than those of 5‐FU at all the doses tested. The inhibitions of the SV40 DNA replication of the samples were much greater than that of the control. The synthesized monomer and polymers showed more antiangiogenesis activity than the control. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1247–1256, 2000     

A novel poly(p‐phenylene) containing alternating poly(perfluorooctylethyl acrylate‐co‐methyl methacrylate) and polystyrene grafts by combination of atom transfer radical polymerization and Suzuki coupling processes

A poly(p‐phenylene) (PP), carrying perfectly alternating, well‐defined poly(perfluorooctylethyl acrylate‐co‐methyl methacrylate) [P(FEA‐co‐MMA)] and polystyrene (PS) side chain grafts, was synthesized by the combination of atom transfer radical polymerization (ATRP) and Suzuki cross‐coupling processes. First, dibromobenzene and diboronic ester functional macromonomers of P(FEA‐co‐MMA) and PS, respectively, were prepared by ATRP. In the second step, PP with lateral alternating P(FEA‐co‐MMA) and PS chains was synthesized by a Suzuki coupling reaction in the presence of Pd(PPh₃)₄ catalyst. The wetting behavior of the polymers was studied by measurements of the static contact angle θ of thin films (200?400 nm thickness) using water and n‐hexadecane as wetting liquids. The obtained fluorinated PP showed high static contact angles with both interrogating liquids, exhibiting simultaneously hydrophobic (θ_w = 111°) and lipophobic (θ_h = 67°) properties. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis and in vitro antitumor activity of phthalimide-based polymers containing camptothecin

To improve the therapeutic efficacy of 20(s)-camptothecin (CPT) polymeric drugs containing CPT have been designed. A new CPT-conjugate, 3,6-endo-methylene-1,2,3,6-tetrahydrophthalimidoacetamidoglycine camptothecin ester (ETPA-gly-CPT), was synthesized by linking its hydroxyl group to the phthalimido monomer through a glycine-glycine spacer. Its homo- and copolymer with acrylic acid (AA) were prepared by photopolymerization using 2,2-dimethoxy-2-phenylacetophenone (DMP) as a photoinitiator. The monomer and its polymers were characterized by IR, ¹H- and ¹³C-NMR spectra. The ETPA-gly-CPT content in poly(ETPA-gly-CPT-co-AA) obtained by elemental analysis was 40 wt.%. The number-average molecular weights of the polymers determined by gel permeation chromatography were as follows: M_n=15,000 for poly(ETPA-gly-CPT), M_n=18,700 for poly(ETPA-gly-CPT-co-AA). The IC₅₀ values of ETPA-gly-CPT and its polymers against cancer cells were much larger than that of CPT.     

Synthesis and characterization of new AB-type poly(etherimide)s containing bisphenol moieties

A series of new AB-type poly(etherimide)s having bisphenol-type moiety was prepared by the one-pot polyimidization using triphenylphosphite(TPP) in N-methyl-2-pyrrolidone(NMP)/pyridine solution at 150°C. Complete cyclodehydration was observed in the polymerizations as well as in model reactions. Polymers were obtained with inherent viscosities in the 0.27–0.49 dL/g range. The M_n and M_w/M_n of poly[4-(1,4-phenyleneoxy-1,4-phenylenehexafluoro-isopropylidene-1,4-phenylene)oxyphthalimide] (4d) with η_inh = 0.49 dL/g were 73,400 g/mol and 1.5, respectively. Most polymers could readily be dissolved in common organic solvents such as DMAc, NMP, and m-cresol. The polymer 4d was soluble even in chloroform. These polymers had glass transition temperatures between 205 and 235°C, and 5% weight loss temperatures in the range of 511–532°C in nitrogen. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3530–3536, 1999     

Ring-Opening Polymerization of Cyclic Monomers with Aluminum Triflate

A green method for the controlled synthesis of aliphatic polymers is presented. The ring-opening polymerizations of cyclic monomers including several lactones, such as caprolactone (CL) or pentadecalactone (PDL), and cyclic anhydride monomers, such as succinic anhydride (SUC) and tetrahydrofuran (THF), catalyzed by a series of metal triflates (trifluoromethanesulfonate) were studied. Aluminum triflate was found to be an advantageous candidate to catalyze the ring-opening polymerization of cyclic monomers. The details of the ring-opening polymerization of CL catalyzed by aluminum triflate were studied. The maximum number average molecular weight (M_n), polydispersity (M_w/M_n) and yield of the obtained poly(-caprolactone) (PCL) at 60 °C for 6 hours were 18,400, 1.94 and 89 wt%, respectively. Those of poly(pentadecalactone) (PPDL) at 100 °C for 6 hours were 12,400, 2.24 and 49 wt%, respectively. The M_n, M_w/M_n and yield of the obtained poly(butylene succinate) (PBS) from SUC and THF at 100 °C for 48 hours were 4,900, 2.03 and 84 wt%, respectively. Furthermore, the mechanism of the polymerization was discussed based on the relationship between the conversion of CL and time. The molecular weight buildup of PCL was linear with a conversion in 50 min before the conversion reached 100 % and with M_w/M_n stabilized at about 1.5. The M_w/M_n of PCL then gradually increased. From these data, a living polymerization with a small transesterification was suggested from the PCL polymerization by aluminum triflate.     

Synthesis and self‐assembly morphologies of amphiphilic multiblock copolymers [poly(ethylene oxide)‐b‐polystyrene]n via trithiocarbonate‐embedded PEO macro‐RAFT agent

An amphiphilic multiblock copolymer [poly(ethylene oxide)‐b‐polystyrene]_n [(PEO‐b‐PS)_n] is synthesized by using trithiocarbonate‐embedded PEO as macro‐RAFT agent. PEO with four inserted trithiocarbonate (M_n = 9200 and M_w/M_n = 1.62) groups is prepared first by condensation of α, ω‐dihydroxyl poly(ethylene oxide) with S, S′‐Bis(α, α′‐dimethyl‐α″‐acetic acid)‐trithiocarbonate (BDATC) in the presence of pyridine, then a series of goal copolymers with different St units (varied from 25 to 218 per segment) are obtained by reversible addition‐fragmentation chain transfer (RAFT) polymerization. The synthesis process is monitored by size exclusion chromatography (SEC), ¹H NMR and FT‐IR. The self‐assembled morphologies of the copolymers are strongly dependent of the length of PS block chains when the chain length of PEO is fixed, some new morphologies as large leaf‐like aggregates (LLAs), large octopus‐like aggregates (LOAs), and coarse‐grain like micelles (CGMs) are observed besides some familiar aggregates as large compound vesicles (LCVs), lamellae and rods, and the effect of water content on the morphologies is also discussed. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6071–6082, 2006     

Various polycarbonate graft copolymers via diels–alder click reaction

In this work, we used Diels–Alder click reaction for the preparation of various types of aliphatic polycarbonates (PCs). We first prepared a novel anthracene‐functionalized cyclic carbonate monomer, anthracen‐9‐ylmethyl 5‐methyl‐2‐oxo‐1,3‐dioxane‐5‐carboxylate (2), followed by ring‐opening polymerization of this monomer to prepare PC with pendant anthracene groups (PC‐anthracene) using 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU)/1‐(3,5‐bis(trifloromethyl)phenyl)‐3‐cyclohexylthiourea (TU) as the catalyst and benzyl alcohol as the initiator in CH₂Cl₂ at room temperature. Subsequently, the resulting PC‐anthracene (M_n,TDGPC = 6000 g/mol, M_w/M_n = 1.22) was grafted with a linear α‐furan protected‐maleimide terminated‐poly(methyl methacrylate) (PMMA‐MI) (M_n,GPC = 3100 g/mol, M_w/M_n = 1.31), or poly(ethylene glycol) (PEG‐MI) (M_n,GPC = 550 g/mol, M_w/M_n = 1.09), or a mixture of PMMA‐MI and PEG‐MI to yield well‐defined PC graft or hetero graft copolymers, PC‐g‐PMMA (M_n,TDGPC = 59000 g/mol, M_w/M_n = 1.22) or PC‐g‐PEG, or PC‐g‐(PMMA)‐co‐PC‐g‐(PEG) (M_n,TDGPC = 39900 g/mol, M_w/M_n = 1.16), respectively, using Diels–Alder click reaction in toluene at 110°C. The Diels–Alder grafting efficiencies were found to be over 97% using UV spectroscopy. Moreover, the structural analyses and the molecular weights of resulting graft copolymers were determined via ¹H NMR and triple detection GPC (TD‐GPC), respectively. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis of Si—H Functional Poly(phenylsilane) and Organosilane Copolymers: Low-valent Titanium Induced Polymerization of Organodichlorosilanes

在低价钛促进下,苯基二氯硅烷进行还原聚合反应生成Si-H官能化的聚苯基硅烷。应用此方法,在温和、中性反应条件下制备出Si-H官能团化的有机聚硅烷共聚物。