聚(对苯二甲酸-1,3-丙二酯)环状低聚物的合成、表征和开环聚合反应

探索了由对苯二甲酰氯和1,3-丙二醇在“假高稀”条件下合成聚(对苯二甲酸-1,3-丙二酯)(PTT)环状低聚物的可行性.通过柱色谱分离了环状低聚物和线形低聚物;用核磁共振、质谱和元素分析表征了产物的化学结构;用GPC和HPLC研究了不同大小环的分布,发现在本文实验条件下合成的PTT环状低聚物主要由二、三、四、五和七聚体构成,其中环状三聚体含量最多,没有发现环状六聚体的存在.PTT环状低聚物的熔程为92.3～222.6℃,熔融后是无色、透明的低粘度液体.于250℃将PTT环状低聚物分别在辛酸亚锡、1-乙基-3-氯四丁基锡氧烷、钛酸四丁酯和三氧化二锑催化下进行开环聚合反应,制备了特性粘数为0.18～0.49dL/g的聚合物.     

Study of the thermal evolution of the cyclic‐oligomer formation in a cyclic‐oligomer‐free PET

A low percentage of cyclic oligomers can be found in poly(ethylene terephthalate) (PET) from its synthesis onward. In this article, a cyclic‐oligomer‐free PET (COFP) obtained by solvent extraction was used to study the thermodynamics of the re‐formation of cyclics from the melt. The cyclic‐oligomer content re‐increased into molten COFP, finally reaching an equilibrium. An analysis of the fraction of the re‐formed cyclic oligomers showed that a majority of cyclic trimer (60–70%) was found at the equilibrium. Before the establishment of the equilibrium, an unusual behavior was observed in the relative proportion of cyclic trimer and tetramer during the first steps of their formation that was probably due to a competition between kinetic and thermodynamic products. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 416–422, 2000     

Cyclic and telechelic ladder polymers derived from tetrahydroxytetramethylspirobisindane and 1,4‐dicyanotetrafluorobenzene

5,5′,6,6′‐Tetrahydroxy‐3,3,3′,3′‐tetramethylspirobisindane was polycondensed with 1,4‐dicyanotetrafluorobenzene in four different solvents at 70 °C. In dimethylformamide, N‐methylpyrrolidone, and sulfolane exclusively, cyclic polymers were detectable by matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectrometry up to masses around 13,000 Da. In dimethyl sulfoxide, linear byproducts were also found. Higher temperatures caused degradation reactions catalyzed by potassium carbonate. Polycondensations performed with the addition of 4‐tert‐butyl catechol or 2,2′‐dihydroxy binaphthyl yielded linear telechelic oligomers. Equimolar mixtures of linear and cyclic ladder polymers were examined by MALDI‐TOF mass spectra to determine how the end groups and the cyclic structure influenced the signal‐to‐noise ratio. The results suggested a preferential detection of the linear chains. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5344–5352, 2006     

Thermodynamics of solutions of cyclic polymethylene ester oligomers in p‐dioxane and chloroform

Differential vapor pressures were measured for mixtures of two cyclic polymethylene ester oligomers in p‐dioxane and chloroform at 25, 30, 35, and 40 °C at five different concentrations ranging from 1 to 20 wt %. The Flory–Huggins interaction parameter (χ) as well as Leonard's interaction parameter (χ′) for flexible and semiflexible rings were calculated and compared to one another. A new method for the estimation of the number of segments of a cyclic polymer is proposed that allows Leonard's equations to be applied correctly to a particular cyclic compound. Consistent differences between χ and χ′ were observed for all studied mixtures, and the differences became smaller if the cyclic oligomers were considered semiflexible. Interestingly, the enthalpic parameter (κ) deduced from values of χ and χ′ did not differ within their uncertainties. This supports the prediction that mixing cyclic polymer compared to its linear counterpart is mainly due to a molecular configurational entropy difference and that this difference should become less pronounced as the cyclic compound becomes larger. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 443–455, 2000     

Polyterephthalates made from Ethylene glycol, 1,4‐cyclohexanedimethanol,and isosorbide

Three series of terephthalate polyesters (copolyesters and terpolyesters) containing 70, 80, and 90 mol % of ethylene glycol respectively, 1,4‐cyclohexanedimethanol (CHDM) and isosorbide in varying ratios, were synthesized by melt polycondensation. It was found that only ～75 mol % of the feeding isosorbide was incorporated in the resulting polyesters and that their content in diethylene glycol oscillated between 2 and 4 mol %. The polyesters had weight‐average molecular weights in the 25,000–33,000 g mol^?1 range and polydispersities between 2 and 2.5. The combined ¹H and ¹³C NMR analysis revealed that the microstructure of all these polyesters was at random. They showed good thermal stability with decomposition temperatures above 400 °C. Their glass‐transition temperatures were observed to increase with the content in cyclic diols, this effect being more pronounced when isosorbide was the replacing comonomer. Only the series containing 90 mol % of ethylene terephthalate units was able to crystallize upon cooling from the melt. Compared isothermal crystallizations revealed that isosorbide was more effective than CHDM in repressing the crystallizability of PET. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis and properties of cyclic diester based aliphatic copolyesters

Melt polycondensation was used to prepare a systematic series of random and amorphous copolyesters using the following cycloaliphatic diesters: dimethyl‐1,4‐cyclohexane dicarboxylate (DMCD), dimethyl bicyclo[2.2.1]heptane‐1,4‐dicarboxylate (DMCD‐1), dimethyl bicyclo[2.2.2]octane‐1,4‐dicarboxylate (DMCD‐2), dimethyl bicyclo[3.2.2]nonane‐1,5‐dicarboxylate (DMCD‐3), 1,4‐dimethoxycarbonyl‐1,4‐dimethylcyclohexane (DMCD‐M) and the aliphatic diols: ethylene glycol (EG) and 1,4‐cyclohexane dimethanol (CHDM). The polymer compositions were determined by nuclear magnetic resonance (NMR) and the molecular weights were determined using size exclusion chromatography (SEC). The polyesters were characterized by dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The copolyester based on DMCD‐2 was observed to have a higher glass transition temperature (T_g up to 115 °C) than the other copolyesters of this study. For poly[x(DMCD‐2)y(DMCD) 30(EG)70(CHDM)], T_g increases linearly with increase of DMCD‐2 mole content. DMA showed that all of the cycloaliphatic copolyesters have secondary relaxations, resulting from the conformational transitions of the cyclohexylene rings. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2162–2169, 2010     

Physically crosslinked elastomers prepared from oligomeric polyolefins with mesogenic units

Two ABA‐type liquid crystalline oligomers were newly synthesized, where A was a mesogenic group and B was polyolefin whose molecular mass was 2470. The A segment was prepared from p‐hydroxyl benzoic acid and terephalic acid. The elastomeric films, whose moduli at 20% elongation were 0.4–1.0 MPa, were obtained by solution casting of the ABA‐type oligomers. Dynamic mechanical analysis and differential scanning calorimetry measurement showed the glass transition of amorphous polyolefin segments, the melting of mesogenic groups, and the meso‐to‐isotropic transition of liquid crystalline phase. The formation of microphase‐separated structures was confirmed by a small‐angle X‐ray scattering (SAXS) measurement. The presence of hexagonal cylinder domains, which were attributed to the aggregation of mesogenic groups in the polyolefin matrix, was also detected by SAXS. These liquid crystalline oligomers showed anisotropy under the crossed Nicoles, and the textures were observed to be nematic. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2247–2253, 2000     

Synthesis and characterization of block poly(ester‐ether‐urethane)s from bacterial poly(3‐hydroxybutyrate) oligomers

Telechelic hydroxylated poly(3‐hydroxybutyrate) (PHB‐diol) oligomers have been successfully synthesized in 90–95% yield from high molar mass PHB by tin‐catalyzed alcoholysis with different diols (mainly 1,4‐butanediol) in diglyme. The PHB‐diol oligomers structure was studied by nuclear magnetic resonance, Fourier transformed infrared spectroscopy MALDI‐ToF MS, and size exclusion chromatography, whereas their crystalline structures, thermal properties and thermal stability were analyzed by wide angle X‐ray scattering, DSC, and thermogravimetric analyses. The kinetic of the alcoholysis was studied and the influence of (i) the catalyst amount, (ii) the diol amount, (iii) the reaction temperature, and (iv) the diol chain length on the molar mass was discussed. The influence of the PHB‐diol molar mass on the thermal stability, the thermal properties and optical properties was investigated. Then, tin‐catalyzed poly(ester‐ether‐urethane)s (PEEU) of M_n = 15,000–20,000 g/mol were synthesized in 1,2‐dichloroethane from PHB‐diol oligomers (P_ester) with modified 4,4'‐MDI and different polyether‐diols (P_ether) (PEG‐2000, PEG‐4000, and PPG‐PEG‐PPG). The influence of the PHB‐diol chain length, the P_ether/P_ester ratio, the polyether segment nature and the PEG chain length on the thermal properties and crystalline structures of PEEUs was particularly discussed. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1949–1961     

Cyclic Oligomers of Phenolphthalein Polyarylene Ether Sulfone （Ketone）： Preparation Through Cyclo-depolymerisation of Corresponding Polymers

Cyclic oligomers of phenolphthalein polyarylene ether sulfone(ketone) were preparedthrough cyclo-depolymerisation of corresponding polymers using CsF as the catalyst in dipolaraprotic solvent DMAc and DMF, and a family of macrocycles containing from dimer up to at leastheptamer were confirmed by GPC, HPLC and MALDI-TOF-MS. The yields of cyclics get ashigh as 86.3% and 87.9% respectively.     

Cyclic oligomer chemistry

Cyclic oligomers of engineering plastics such as polycarbonate and aromatic polyesters have been known for some time, being formed at very low levels during commercial manufacture. At GE Global Research, we have devised methods for high‐yielding and selective preparation of such cyclic oligomers, that are amenable to commercial manufacture. The mixtures of cyclic oligomers have melting points significantly lower than individual ring sizes, and have very low viscosities in the melt. Ring‐opening polymerization using appropriate initiators affords rapid reactions (2–6 min) without measurable exotherm, providing very high‐molecular‐weight polymers and without reaction byproducts. These materials have been scaled to commercial quantities, and have shown to be extremely useful for fabrication of glass and carbon fiber composites with high‐fiber fractions. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1151–1164, 2008     

Polyaddition of bifunctional cyclic carbonate with diamine in ionic liquids: In situ ion composite formation and simple separation of ionic liquid

Polyaddition of bifunctional cyclic carbonates and diamines in ionic liquids proceeded smoothly to afford polyurethanes having hydroxyl groups in the side chain (i.e., poly(hydroxyurethane)). The reaction mixtures separated into ionic liquids and ionic composites consisting of poly(hydroxyurethane) and ionic liquids. The ionic composites originated from the interactions between hydroxyl groups in the side chains and the ionic liquids, confirmed by IR spectroscopic analysis. When the polyaddition was conducted in the mixed solvent consists of water and N‐n‐butylimidazolium hexafluorophosphate. After the reaction, the polymer and the ionic liquid could be separated easily. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4629–4635, 2009     

Synthesis,characterization, and ring-opening polymerization of novel high Tg macrocyclic oligomers based on 1,2-dihydro-4-(4-hydroxyphenyl)(2H)- phthalazin-1-one

Preparation of novel high T_g (220–280°C) macrocyclic oligomers in high yield by the reaction of 1,2-dihydro-4-(4-hydroxyphenyl)(2H)phthalazin-1-one with activated difluoro-monomers is described. The reaction, conducted under pseudo-high dilution conditions, produces cyclic oligomers in 90–97% isolated yield. Detailed structural characterization of these novel oligomers by the combination of NMR, MALDI–TOF–MS, GPC, and reverse-phase HPLC confirm the cyclic nature and reveal the composition of these cyclic oligomers. MALDI–TOF–MS which enables the detection of oligomers with mass up to 6000 Da, is shown to be a very powerful tool for determination of and the proof of the cyclic nature of the cyclic oligomers. The MALDI results provide answers to the possible combinations of monomer units in the cyclic oligomeric components for random co-cyclic oligomers. Rheological measurement of cyclic oligomers 3c shows that the cyclic oligomers are thermally stable in the melt and the molten cyclic oligomers essentially behave like Newtonian fluids. At 340°C and 100 s⁻¹ the steady-state shear viscosity of the molten cyclic oligomers 3c is only about 14 poise. Ring-opening polymerization of the co-cyclic oligomers 4 to a high molecular weight polymer with M_w = 87,000 is achieved by heating at 340°C for 45 min in the presence of a nucleophilic initiator. © 1996 John Wiley & Sons, Inc.     

Novel synthesis of cyclic methylvinylsiloxanes by the reaction of methylvinyl diethoxysilane with phosphorous pentachloride

We report a novel synthesis of the cyclic oligomers [(H₂C?CH)(CH₃)SiO]_n obtained by the reaction between phosphorous pentachloride and methylvinyl diethoxysilane. According to gas chromatography/mass spectrometry data, the reaction product consisted of a mixture of cyclic oligomers in which the most important fractions were composed of cycles with n = 5, 6, or 7. The reaction product was also characterized by Fourier transform infrared and ¹H and ¹³C NMR spectroscopy. Experimental results suggested a new kind of reaction between the phosphorous pentachloride and terminal olefins directly bonded to silicon, which was probably associated with sterical effects favoring C? O? Si bond cleavage of ethoxy groups instead of the conventional addition of phosphorous pentachloride to olefinic linkages. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3182–3189, 2002     

Synthesis and ring‐opening polymerization of co‐cyclic(aromatic aliphatic disulfide) oligomers

An effective approach was presented for the synthesis of co‐cyclic(aromatic aliphatic disulfide) oligomers by catalytic oxidation of aromatic and aliphatic dithiols with oxygen in the presence of a copper‐amine catalyst. The aromatic dithiols can be 4,4′‐oxybis(benzenethiol), 4,4′‐diphenyl dithiol, 4,4′‐diphenylsulfone dithiol. The aliphatic dithiols can be 1,2‐ethanedithiol, 2,3‐butanedithiol, 1,6‐hexane dithiol. The co‐cyclic(aromatic aliphatic disulfide) oligomers were characterized by gradient HPLC, MALDI‐TOF‐MS, GPC, ¹H‐NMR, TGA, and DSC techniques. The glass transition temperatures of these co‐cyclics ranged from ?11.3 to 56.6°C. In general, these co‐cyclic(aromatic aliphatic disulfide) oligomers are soluble in common organic solvents, such as CHCl₃, THF, DMF, DMAc. These co‐cyclic oligomers readily underwent free radical ring‐opening polymerization in the melt at 180°C, producing linear, tough and high molecular weight poly(aromatic aliphatic disulfide)s. The glass transition temperatures of these polymers ranged from ?3.7 to 107.8°C that are higher than those of corresponding co‐cyclics. Copyright © 2003 John Wiley & Sons, Ltd.     

Synthesis and properties of π‐conjugated dithiafulvene oligomers by addition of a monofunctionalized compound

Dithiafulvene oligomers ( 3 ) were prepared by cycloaddition polymerization of aldothioketenes with their alkynethiol tautomers derived from 1,4‐diethynylbenzene ( 2 ) with the addition of 1‐ethynyl‐4‐methylbenzene ( 1 ) as a monofunctionalized compound. Different feed ratios of 2 / 1 were used to control the molecular weights of 3 . The structures of 3 were confirmed by IR and ¹H NMR spectroscopies in comparison with those of 2‐(4‐tolylidene)‐4‐tolyl‐1,3‐dithiol ( 4 ) as a model compound, which was obtained by the treatment of lithium 2‐tolylethynethiolate with water in Et₂O. The number‐average degree of polymerization (DP) and the number‐average molecular weight were measured by gel permeation chromatographic and ¹H NMR analysis. DP increased with an increasing feed ratio of 2 / 1 . The ultraviolet–visible spectra of 3 in diluted acetonitrile showed that the absorption maxima of 3 increased with an increasing DP of 3 . These redshifts are ascribed to an effective expansion of the π‐conjugation system in 3 . The oligomers exhibited a maximum conjugation length of seven repeating units. The redox properties of 3 were examined by cyclic voltammetry. The oxidation half‐peak potentials (E_p/2) of 3 were slightly cathodically shifted with increasing DP. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 708–715, 2003     

Preparation of macrodiols and polyols by chopping high‐molecular‐weight aliphatic polycarbonates

High‐molecular‐weight poly(1,4‐butylene carbonate) (PBC) (M_n: 40,000?90,000) was prepared through the condensation polymerization of dimethyl carbonate (DMC) and 1,4‐butanediol (BD) in the presence of 0.05 mol % sodium alkoxide catalyst. The subsequent feeding of 15 mol % HOAOH, such as 1,6‐hexanediol, 1,5‐pentanediol, 1,4‐cyclohexanedimethanol, or 1,4‐benzenedimethanol and stirring at 190–150 °C converted the extremely thick high‐molecular‐weight polymer to low‐molecular‐weight macrodiols with GPC‐measured M_n ～2000. The analysis of the ¹H NMR spectra indicated that the –A– units and 1,4‐butylene units were randomly distributed in the resulting oligomers. The chopping of the high‐molecular‐weight PBC using either triols or tetraols such as glycerol propoxylate, 1,1,1‐tris(hydroxymethyl)ethane, or pentaerythritol also afforded macropolyols containing branched chains with GPC‐measured M_n ～2000. When the chopped polymers were genuine PBCs, the resulting macrodiols or polyols were in a waxy state at room temperature. However, permanently oily compounds were obtained when the chopped polymers were prepared using 0.90 mole fraction of BD admixed with various other diols. The macrodiols and polyols synthesized in this study may have potential applications in the polyurethane industry. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1570–1580     

Bis[4-monosubstituted-5(4H)oxazolinones] as coupling agents for block copolymer synthesis: Reaction with amine-terminated oligomers and with hydroxy-terminated/amine-terminated oligomer mixtures

Block copolymers were prepared by the bulk reaction of mixtures of amine-terminated aliphatic polyamides and polyethers with bis[4-monosubstituted 5(4H)-oxazolinones] as the coupling agents. The simultaneous chain-coupling reaction of amine-terminated polyethers and hydroxy-terminated polyesters with these coupling agents also was investigated. As indicated by NMR and size exclusion chromatography studies, block copolymers of M_n ≥ 10,000 were obtained without side reactions in a much shorter reaction time than required when the conventional reaction was used between oligomers bearing mutually reactive end-groups. The block copolymers behaved as thermoplastic elastomers. Their thermal and thermomechanical properties were evaluated by differential scanning calorimetry and dynamic mechanical thermal analysis and compared to the block copolymers synthesized in the conventional way. When low molar mass oligomers were used (M_n ≤ 1000), copolymers of low crystallinity or amorphous copolymers were obtained. This was assigned to the disruption of chain regularity induced by the presence of the chain-coupling-agent moieties. However, properties comparable to those of copolymers obtained by using the conventional method were obtained by reacting oligomers of M_n ≥ 2000. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4412–4421, 1999     

Synthesis and characterization of poly(arylene ether sulfone)s with trans‐1,4‐cyclohexylene ring containing ester linkages

trans‐1,4‐Cyclohexylene ring containing acid chloride monomers were incorporated into poly(arylene ether sulfone) (PAES) backbones to study their effect on mechanical and thermal properties. The trans‐1,4‐cyclohexylene ring containing acid chloride monomers were synthesized and characterized by NMR and high‐resolution mass spectrum. trans‐1,4‐Cyclohexylene containing PAESs were synthesized from the acid chloride monomers and hydroxyl terminated polysulfone oligomers with a pseudo‐interfacial method and a solution method. These PAESs, with trans‐1,4‐cyclohexylene ring containing ester linkages, were fully characterized by NMR, thermogravimetric analysis, differential scanning calorimetry (DSC), size exclusion chromatography, and dynamic mechanical analysis (DMA). The tensile properties were also evaluated. The polymers made with the pseudo‐interfacial method had relatively low molecular weights when compared to the solution method where much higher molecular weight polymers were obtained. Crystallinity was promoted in the low molecular weight biphenol‐based PAES samples with the pseudo‐interfacial method. The crystallinity was confirmed by both the DSC and the wide angle X‐ray diffraction results. The tensile test results of the high molecular weight polymers suggested that incorporation of the trans‐1,4‐cyclohexylene ring containing linkage slightly improved the ultimate elongations while maintaining the Young's moduli. The trans‐1,4‐cyclohexylene ring containing PAESs also showed higher sub‐T_g relaxations in DMA when compared with their terephthaloyl containing analog. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis and characterization of new highly permeable polyamideimides from dianhydride monomers containing amide functions: An application to the purification of a fuel octane enhancer (ETBE) by pervaporation

Six polyamideimides (PAI) were synthesized from six dianhydride monomers containing amide functions. The dianhydride monomers were obtained from the reaction of trimellitic anhydride chloride with six aromatic diamines—1,4‐phenylenediamine, 2,2‐bis(4‐aminophenyl) propane, 4,4′‐oxydianiline, 4,4′‐methylenedianiline, 1,1‐bis(4‐aminophenyl)cyclohexane, and bis(4‐aminophenyl)sulfone—by a low‐temperature condensation with yields ranging from 35 to 98% depending on the monomer solubility in organic media. The monomers were characterized by Fourier transform infrared (FTIR) and ¹H NMR. In accordance with a synthesis scheme implying the reaction of a macrodiisocyanate with dianhydride monomers containing amide functions, six PAIs with a highly flexible soft block (polytetramethylene glycol PTMG 650) were synthesized with inherent viscosities ranging from 0.38 to 1.3 dL/g. Their characterization by FTIR and ¹H NMR fully confirmed their chemical structure. The strong physical crosslinking provided by polar hard blocks containing up to eight aromatic rings enabled the casting of PAI films that were very tough in the dry state and could withstand exposure to rather strong solvating media (e.g., ethers, alcohols, and chlorinated solvents). First experiments showed these materials could be good candidates for membrane‐separation applications. They revealed interesting features for the separation of organic aprotic–protic mixtures as shown by the first results obtained for the purification of a fuel octane enhancer (ethyl‐tert‐butyl ether) used in the European Community. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 614–630, 2000     

Polyesters containing sulfur. VIII. New benzophenone‐derivative thiopolyesterdiols synthesis and characterization. Their use for thermoplastic polyurethanes preparation

The new linear thiopolyesterdiols (PEs) containing sulfur in the main chain were synthesized by melt polycondensation of newly obtained benzophenone‐4,4′‐bis(methylthioacetic acid) with excess of 1,4‐butanediol, 1,5‐pentanediol, and 1,6‐hexanediol. All these PEs (M _n of 2000–2600) were converted to thiopoly(ester‐urethane)s (PEUs) by polyaddition reaction with hexamethylene diisocyanate or 4,4′‐diphenylmethane diisocyanate, which was carried out in melt at the ratio of NCO/OH = 1. The resulting thermoplastic PEUs were amorphous and elastomeric, with elongation at break ranging from 630 to 1200%. The polymers were characterized by Fourier transform infrared, ¹H NMR, thermogravimetric analysis, differential scanning calorimetry, and in the case of PEUs, Shore A/D hardness and tensile properties. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3977–3983, 2000