RING-OPENING POLYMERIZATION OF TRIMETHYLENE CARBONATE BY CALIX[8]ARENE-NEODYMIUM*

Ring-opening polymerization of trimethylene carbonate (TMC) with a rare earth calixarene compound as catalysthas been studied for the first time. The effect of TMC/Nd (molar ratio) and polymerization conditions were investigated indetail. It was found that calix[8]arene-neodymium is a highly effective catalyst for the bulk polymerization of TMC and giveshigh molecular weight (M_v = 60,000) polymer. The optimum conditions of TMC polymerization were found to be asfollows:TMC/Nd (molar ratio) = 2,000, 80℃, 16 h. The polymers were characterized by NMR, GPC and DSC. Studying themechanism by NMR showed that the polymerization of TMC catalyzed by calix[8]arene-neodymium proceeds via a cationicmechanism.     

Organocatalysts for the controlled "immortal" ring-opening polymerization of six-membered-ring cyclic carbonates: a metal-free, green process

Six-membered cyclic carbonates, namely trimethylene carbonate (TMC), 3,3-dimethoxytrimethylene carbonate (DMTMC) and 3-benzyloxytrimethylene carbonate (BTMC), undergo controlled "immortal" ring-opening polymerization (iROP) under mild conditions (bulk, 60-150 °C), by using organocatalysts, including an amine [4-N,N-dimethylaminopyridine (DMAP)], a guanidine [1,5,7-triazabicyclo-[4.4.0]dec-5-ene (TBD)], or a phosphazene [2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine (BEMP)], in the presence of an alcohol [benzyl alcohol (BnOH), 1,3-propanediol (PPD), glycerol (GLY)] that acts as both a co-initiator and a chain-transfer agent. Remarkably, such organocatalysts remain highly active in the iROP of technical-grade, unpurified TMC. Under optimized conditions, as much as 100,000 equivalents of TMC were fully converted by as little as 10 ppm of BEMP with the simultaneous growth of as many as 200 polymer chains, allowing the preparation of high molar mass poly(trimethylene carbonate)s (up to 45,800 g mol(-1)). These catalyst systems enable among the highest activities (TOF=55,800 h(-1)) and productivities (TON=95,000) ever reported for the ROP of TMC.     

Hydrophilic–hydrophobic AB diblock copolymers containing poly(trimethylene carbonate) and poly(ethylene oxide) blocks

AB‐type block copolymers with poly(trimethylene carbonate) [poly(TMC); A] and poly(ethylene oxide) [PEO; B; number‐average molecular weight (M_n) = 5000] blocks [poly(TMC)‐b‐PEO] were synthesized via the ring‐opening polymerization of trimethylene carbonate (TMC) in the presence of monohydroxy PEO with stannous octoate as a catalyst. M_n of the resulting copolymers increased with increasing TMC content in the feed at a constant molar ratio of the monomer to the catalyst (monomer/catalyst = 125). The thermal properties of the AB diblock copolymers were investigated with differential scanning calorimetry. The melting temperature of the PEO blocks was lower than that of the homopolymer, and the crystallinity of the PEO block decreased as the length of the poly(TMC) blocks increased. The glass‐transition temperature of the poly(TMC) blocks was dependent on the diblock copolymer composition upon first heating. The static contact angle decreased sharply with increasing PEO content in the diblock copolymers. Compared with poly(TMC), poly(TMC)‐b‐PEO had a higher Young's modulus and lower elongation at break. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4819–4827, 2005     

Homopolymerization and copolymerization kinetics of trimethylene carbonate bearing a methoxyethoxy side group

The polymerization kinetics of 5‐[2‐{2‐(2‐methoxyethoxy)ethyoxy}‐ethoxymethyl]‐5‐methyl‐trimethylene carbonate (TMCM‐MOE3OM) synthesized using the organocatalyst 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) were studied and compared to those with the commonly used catalyst/initiator for ring‐opening polymerization of cyclic carbonates and esters, stannous 2‐ethylhexanoate. Further, the utility of each of these catalysts in the copolymerization of TMCM‐MOE3OM with trimethylene carbonate (TMC) and l ‐lactide (LLA) was examined. Regardless of conditions with either catalyst, homopolymerization of TMCM‐MOE3OM yielded oligomers, having number average molecular weight less than 4000 Da. The resultant molecular weight was limited by ring‐chain equilibrium as well as through monomer autopolymerization. Interestingly, autopolymerization of TMC was also achieved with DBU as the catalyst. Copolymerization with TMC using stannous 2‐ethylhexanoate as the catalyst yielded random copolymers, while diblock copolymers were formed by copolymerization with LLA. With DBU as the catalyst, copolymers with LLA could not be formed, while blocky copolymers were formed with TMC. These findings should be useful in the incorporation of this monomer in the design of polymer biomaterials. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 544–552     

Lipase‐Catalyzed transformation of Poly(trimethylene carbonate) into Cyclic Monomer,Trimethylene Carbonate: A New Strategy for Sustainable Polymer Recycling Using an Enzyme

The enzymatic degradation and polymerization using an enzyme were carried out with respect to the establishment of a sustainable chemical recycling system for poly(trimethylene carbonate) [P(TMC)] which is a potentially biodegradable synthetic plastic. The enzymatic transformation of P(TMC)s having an M_n of 3000~48000 using Candida antarctica lipase (lipase CA) in acetonitrile at 70 °C afforded the corresponding cyclic monomer, trimethylene carbonate (TMC: 1,3‐dioxan‐2‐one), in a yield of up to 80%. Thus obtained TMC readily polymerized again using both fresh lipase CA and recovered lipase CA.     

三亚甲基环碳酸酯及2,2-二甲基三亚甲基环碳酸酯开环均聚合*

生物降解聚合物聚三亚甲基环碳酸酯（PTMC）及聚2,2-二甲基三亚甲基环碳酸酯（PDTC）在药物控释载体及其它生物医学技术领域有着良好的应用前景。与脂肪族聚酯不同,PTMC、PDTC降解时,不会产生有害的酸性化合物。PTMC、PDTC主要由三亚甲基环碳酸酯（TMC）及2,2-二甲基三亚甲基环碳酸酯（DTC）开环均聚合制备。本文总结了催化TMC、DTC开环均聚合的不同催化剂及其聚合机理,综述了近年来国内外在TMC、DTC均聚合催化剂开发上的研究进展,并对生物相容性催化剂如稀土催化剂、Ca、Mg、Zn、Fe催化剂以及酶催化剂催化TMC、DTC开环聚合的优缺点进行了比较。     

Anionic lanthanide phenoxide complexes as novel single‐component initiators for the polymerization of ε‐caprolactone and trimethylene carbonate

The anionic lanthanide‐sodium‐2,6‐di‐tert‐butyl‐phenoxide complexes [Ln(OAr)₄][Na(DME)₃]·DME (Ln = Nd 1 (neodymium), Sm 2 (samarium), or Gd 3 (gadolium); DME = dimethoxyethane) were synthesized by the reaction of anhydrous LnCl₃ with 4 equiv of sodium‐2,6‐di‐tert‐butyl‐phenoxide NaOAr in high yields and structurally characterized. These complexes showed high catalytic activity in the ring‐opening polymerizations of ?‐caprolactone (?‐CL) and trimethylene carbonate (TMC). The catalytic activity profoundly depended on the lanthanide metals. The active order of Gd < Sm < Nd for the polymerization of ?‐CL and TMC was observed. The polymers obtained with these initiators all showed a unimodal molecular weight distribution, indicating that the [Ln(OAr)₄][Na(DME)₃]·DME anionic complexes could be used as single‐component initiators. The anionic complex was more efficient than the corresponding neutral complex, Ln(OAr)₃(THF)₂. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1210–1218, 2007     

Bifunctional imidodiphosphoric acid‐catalyzed controlled/living ring‐opening polymerization of trimethylene carbonate resulting block, α,ω‐dihydroxy telechelic,and star‐shaped polycarbonates

The ring‐opening polymerization (ROP) of trimethylene carbonate (TMC) using imidodiphosphoric acid (IDPA) as the organocatalyst and benzyl alcohol (BnOH) as the initiator has been investigated. The polymerization proceeded without decarboxylation to afford poly(trimethylene carbonate) (PTMiC) with controlled molecular weight and narrow polydispersity. ¹H NMR, SEC, and MALDI‐TOF MS measurements of the obtained PTMC clearly indicated the quantitative incorporation of the initiator at the chain end. The controlled/living nature for the IDPA‐catalyzed ROP of TMC was confirmed by the kinetic and chain extension experiments. A bifunctional activation mechanism was proposed for IDPA catalysis based on NMR and FTIR studies. Additionally, 1,3‐propanediol, 1,1,1‐trimethylolpropane, and pentaerythritol were used as di‐ol, tri‐, and tetra‐ol initiators, producing the telechelic or star‐shaped polycarbonates with narrow polydispersity indices. The well‐defined diblock copolymers, poly(trimethylene carbonate)‐block‐poly(δ‐valerolactone) and poly(trimethylene carbonate)‐block‐poly(ε‐caprolactone), have been successfully synthesized by using the IDPA catalysis system. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1009–1019     

Polycarbonate microspheres containing mitomycin C and magnetic powders as potential hepatic carcinoma therapeutics

The polycarbonate copolymer poly(trimethylene carbonate-co-5,5-dimethyl trimethylene carbonate) (P(TMC-co-DTC)) was synthesized by the polymerization of trimethylene carbonate (TMC) and 5,5-dimethyl trimethylene carbonate (DTC) using tin (II) 2-ethylhexanoate [Sn(Oct)(2)] as a catalyst. In vitro degradation tests indicated this polycarbonate copolymer degraded slowly in phosphate buffer saline solution (PBS, 0.1 mol/L, at 37°C). Magnetic polymer microspheres (MMC-PC-M) generated from the P(TMC-co-DTC) copolymer and containing Fe(3)O(4) magnetic ultrafine powders and an anticancer drug, mitomycin C (MMC) were prepared by a solvent evaporation technique. These anticancer magnetic polycarbonate microspheres showed strong magnetic responsiveness and high MMC loading capacity. In vitro drug release studies indicated that these microspheres sustained steady release rates of MMC in PBS. In vitro cytotoxicity assays demonstrated the microspheres were strongly inhibitory to human hepatic carcinoma (Bel-7204) cells. In vivo site-specific therapy in nude mice with human hepatic carcinoma indicated that the microspheres possessed markedly high antitumor activity against human hepatic carcinoma (Bel-7204).     

纳米级固定化猪胰脂肪酶催化三亚甲基碳酸酯的开环聚合研究

以纳米级固定化猪胰脂肪酶(IMPPL)催化三亚甲基碳酸酯(TMC)的开环聚合,研究了IMPPL浓度、聚合反应温度和聚合反应时间对聚三亚甲基碳酸酯(PTMC)分子量和产率的影响.同时也研究了回收再利用的IMPPL对TMC开环聚合的催化作用以及IMPPL对PTMC的降解作用.实验结果表明,IMPPL不仅在60～100℃能有效地催化TMC的开环聚合,而且在较高的温度下IMPPL可以有效地催化PTMC的降解.回收使用的固定化酶可表现较高的催化活性及重复利用性.     

超高分子量聚苯乙烯的合成和聚合反应动力学

杯芳烃钕与Mg(n Bu) 2 、HMPA所组成的三元络合催化剂用于苯乙烯配位聚合能以高收率制得超高分子量聚苯乙烯 .以甲苯为溶剂 ,在一定条件下制成三元配位催化剂 ,当 [Nd]=8× 10 - 4mol L ,[St]=4 .0mol L ,Mg Nd =2 0 .0 (摩尔比 ) ,HMPA Mg =1.0 (摩尔比 ) ,5 0℃聚合 4 5min ,聚合转化率可达到 80 %左右 .所得聚苯乙烯的重均分子量高达 2 10× 10 4 ,分子量分布指数为 1.6 1.间规聚苯乙烯含量为 81% .动力学研究表明 ,聚合反应速率与单体和主催化剂 杯 [6 ]芳烃钕的浓度分别呈 1次方关系 ,聚合反应的表观活化能为 4 1.7kJ mol     

Homoleptic lanthanide guanidinate complexes: The effective initiators for the polymerization of trimethylene carbonate and its copolymerization with ε‐caprolactone

The ring‐opening polymerization of trimethylene carbonate (TMC) using homoleptic lanthanide guanidinate complexes [RNC(NR′₂)NR]₃Ln as single component initiators has been fully investigated for the first time. The substituents on guanidinate ligands and center metals show great effect on the catalytic activities of these complexes, that is, ? N(CH₂)₅ > ? NⁱPr₂ > ? NPh₂ (for R′), ? Cy > ? ⁱPr (for R), and Yb > Sm > Nd. Among them, [Ph₂NC(NCy)₂]₃Yb shows the highest catalytic activity. Some features and kinetic behaviors of the TMC polymerization initiated by [Ph₂NC(NCy)₂]₃Yb were studied in detail. The polymerization rate is first order, with the monomer concentration and M_n of the polymer increasing with the polymer yield increasing linearly. The results indicated the present system having “living character.” A mechanism that the polymerization occurs via acyl‐oxygen bond cleavage rather than alkyl‐oxygen bond cleavage was proposed. The copolymerization of TMC with ?‐caprolactone (ε‐CL) initiated by [Ph₂NC(NCy)₂]₃Yb was also tested. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1778–1786, 2005     

Rapid synthesis of poly(trimethylene carbonate) by microwave-assisted ring-opening polymerization

Poly(trimethylene carbonate) (PTMC) was synthesized successfully by microwave-assisted ring-opening polymerization of trimethylene carbonate. The polymerizations were carried out in a single-mode microwave oven using ethylene glycol (EG) as the initiator in the absence of any metallic compound catalyst. The temperature-time profiles of the reaction mixture were investigated at different power levels and EG concentrations. The molar mass of the resulting PTMC and TMC monomer conversion by the microwave method is higher than those by the conventional method. Thermal properties of the resulting polymers were studied by differential scanning calorimetry. Microwave irradiation proved to be an effective and efficient method for the preparation of PTMC.     

Discrete cationic zinc and magnesium complexes for dual organic/organometallic-catalyzed ring-opening polymerization of trimethylene carbonate

We describe herein an original approach for the efficient immortal ring-opening polymerization (iROP) of trimethylene carbonate (TMC) under mild conditions using dual-catalyst systems combining a discrete cationic metal complex with a tertiary amine. A series of new zinc and magnesium cationic complexes of the type [{NNO}M](+) [anion](-) ({NNO}(-) = 2,4-di-tert-butyl-6-{[(2'-dimethylaminoethyl)methylamino]methyl}phenolate; M = Zn, [anion](-) = [B(C(6)F(5))(4)](-) (2), [H(2)N-{B(C(6)F(5))(3)}(2)](-) (3), and [EtB(C(6)F(5))(3)](-) (4); M = Mg, [anion](-) = [H(2)N{B(C(6)F(5))(3)}(2)](-) (7)) have been prepared from the corresponding neutral compounds [{NNO}ZnEt] (1) and [{NNO}-Mg(nBu)] (6). Compounds 2-4 and 7 exist as free ion pairs, as revealed by (1)H, (13)C, (19)F, and (11) B?NMR spectroscopy in THF solution, and an X-ray crystallographic analysis of the bis(THF) adduct of compound 7, 7?(THF)(2). The neutral complexes 1 and 6, in combination with one equivalent or an excess of benzyl alcohol (BnOH), initiate the rapid iROP of TMC, in bulk or in toluene solution, at 45-60?°C (turnover frequency, TOF, up to 25-30,000?mol(TMC)?mol(Zn)?h(-1) for 1 and 220-240,000?mol(TMC)?mol(Mg)?h(-1) for 6), to afford H-PTMC-OBn with controlled macromolecular features. ROP reactions mediated by the cationic systems 2/BnOH and 7/BnOH proceeded much more slowly (TOF up to 500 and 3000?mol(TMC)?mol(Zn or Mg)?h(-1) at 110?°C) than those based on the parent neutral compounds 1/BnOH and 6/BnOH, respectively. Use of original dual organic/organometallic catalyst systems, obtained by adding 0.2-5?equiv of a tertiary amine such as NEt(3) to zinc cationic complexes [{NNO}Zn](+) [anion](-) (2-4), promoted high activities (TOF up to 18,300?mol(TMC)?mol(Zn)?h(-1) at 45?°C) giving H-PTMC-OBn with good control over the M(n) and M(w)/M(n) values. Variation of the nature of the anion in 2-4 did not significantly affect the performance of these catalyst systems. On the other hand, the dual magnesium-based catalyst system 7/NEt(3) proved to be poorly effective.     

Copolymerization of carbon dioxide and oxetane catalyzed by aluminum porphyrin complex system

Tetraphenylporphinatoaluminum chloride ([TPP]AlCl) catalyst and tetra-n-butylammonium bromide (TBAB) cocatalyst system is effective for the copolymerization of CO₂ and oxetane even under low CO₂ pressure (~2 MPa). In the presence of toluene as a solvent, poly(trimethylene carbonate) (PTMC) containing >99% of carbonate linkages with M_n = 8600 and M_w/M_n = 1.70 was synthesized. This is the first report of PTMC formation with excellent ratio of carbonate linkages from oxetane and CO₂. According to the kinetic analysis, proton nuclear magnetic resonance (¹H NMR) and matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS) measurements of the products, PTMC was mainly synthesized via (i) the trimethylene carbonate (TMC) formation from CO₂ and oxetane and (ii) the successive ring-opening polymerization of TMC.     

A comparison of polymerization characteristics and mechanisms of ε-caprolactone and trimethylene-carbonate with rare earth halides

Characteristics and mechanisms of the ring opening-polymerizations of ε-caprolactone (CL) and trimethylene carbonate (TMC) with rare earth halides have been compared for the first time. It has been found that rare earth halides show high catalytic activities for the polymerization of TMC, but very low activities for that of CL polymerization. The copolymerization of CL and TMC can proceed only in the presence of high contents of TMC in the comonomer feed. The copolymerization rate decreases rapidly with increasing molar fraction of CL in the feed. The mechanism study by IR, ¹H-, ¹³C-, and ³¹P-NMR spectra shows that the first step reaction of the polymerization of TMC or CL with rare earth halide is the complexation of monomer to the rare earth ion. The strong coordination of TMC to rare earth ion induces the ring-cleavage of TMC and generation of the cationic species, which initiate the polymerization of TMC via a cationic process. However, the polymerization of CL with rare earth halide is an “activated-hydrolysis” process, in which rare earth catalyst does not initiate the polymerization but serves as an activator of CL. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1339–1352, 1997     

Use of samarium (III) acetate as initiator in ring-opening polymerization of trimethylene carbonate

Abstract

In this work was evaluated the activity of samarium acetate (III) (Sm(OAc)₃) as a possible initiator in the polymerization by ring opening of trimethylene carbonate (TMC). All polymerizations were carried out under solvent-free melt conditions in ampoules-like flasks, equipped with a magnetic stirrer. The effects of different parameters of reaction, such as molar ratio monomer to initiator, temperature and reaction time, on typical variables of polymers, e.g., conversion of TMC to poly(trimethylene carbonate) (PTMC), dispersity and molar mass, were analyzed. The molar ratio of monomer to initiator was varied between 0 and 1000?mol/mol and the temperature among 70 and 150?°C. Nuclear Magnetic Resonance (¹H-NMR and HMBC) and Size Exclusion Chromatography (SEC) were used to characterize the polymers. The results indicate that the Sm(OAc)₃ induces the polymerization of TMC to high conversion with number-average molecular weights of 3.11?×?10³ to 38.40?×?10³?Da. Based on the ¹H-NMR end-group analysis of low-molecular-weight PTMC, it was proposed a coordination–insertion mechanism for the polymerization, with a breakdown of the acyl-oxygen bond of the TMC. In according to the kinetic study carried out, the polymerization rate is first-order with respect to monomer concentration with apparent rate constants of k_ap?=?7.02?×?10^?4?mol?×?L^?1?×?h^?1.     

Polymerization mechanism of trimethylene carbonate carried out with zinc(II) acetylacetonate monohydrate

The proposed mechanism of initiation and course of ring‐opening polymerization of cyclic trimethylene carbonate (TMC) involving zinc(II) acetylacetonate is in accordance with the mechanism of monomer activation. At the first stage of the process, coordination of carbonate to Zn(Acac)₂ · H₂O complex occurs with the release of weakly coordinated water molecules. This free water molecule reacts with active TMC–Zn(Acac)₂ complex. The reaction results in the formation of propanediol and CO₂ emission. During further stages of the investigated process, the formed propanediols, or later the oligomeric diols produced with polymerization, are cocatalysts of the chain propagation reaction. The chain propagation occurs because of repeating activation of the TMC monomer through the creation of an active structure resulting in the exchange/transfer reaction between the zinc complex and the monomer, with its following attachment to the hydroxyl groups, carbonate ring opening, and formation of the carbonic unit of polymer chain. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

New polymer syntheses. CXI. Aliphatic polyesters by the ring‐opening polycondensation of glutaric anhydride with ethylene or trimethylene carbonate

Several polycondensations of ethylene carbonate with succinic anhydride or glutaric anhydride (GA) were conducted in bulk. Low molar mass polyesters were obtained with pyridine‐type catalysts and GA. Analogous polycondensations of trimethylene carbonate (TMC) and GA were successful when quinoline, 4‐(N,N‐dimethylamino)pyridine, or BF₃ · OEt₂ was used as a catalyst. Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectra revealed the formation of cyclic oligoesters and polyesters by backbiting degradation. Monomer mixtures containing an excess of TMC yielded copoly(ester carbonate)s with number‐average molecular weights up to 16,000 Da. Analogous copoly(ester carbonate)s were obtained from TMC and 3,3′‐tetramethylene glutaric anhydride. Furthermore, combined polycondensation/ring‐opening polymerization reactions of TMC and GA with L ‐lactide or ?‐caprolactone were studied. All copolymers were characterized by viscosity measurements and by IR, ¹H, and ¹³C NMR spectroscopy. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4357–4367, 2002     

One‐step synthesis of block copolymers using a hydroxyl‐functionalized trithiocarbonate RAFT agent as a dual initiator for RAFT polymerization and ROP

A range of well‐defined block copolymers were synthesized using 4‐cyano‐4‐(dodecylsulfanylthiocarbonyl)sulfanylpentanol (CDP) as a dual initiator for reversible addition‐fragmentation chain transfer (RAFT) polymerization and ring‐opening polymerization (ROP) in a one‐step process. Styrene, (meth)acrylate, and acrylamide monomers were polymerized in a controlled manner for one block composed of vinyl monomers, and δ‐valerolactone (VL), ε‐caprolactone (CL), trimethylene carbonate (TMC), and L ‐lactide (LA) were used for the other block composed of cyclic monomers. Diphenyl phosphate was used as a catalyst for the ROP of VL, CL, and TMC, and 4‐dimethyamino pyridine for the ROP of LA. These catalysts did not interfere with RAFT polymerization and the synthesis of various block copolymers proceeded in a controlled manner. CDP was found to be a very useful dual initiator for a one‐step synthesis of various block copolymers by a combination of RAFT polymerization and ROP. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013