环单体的合成,聚合及与环氧树脂的固化反应

合成了新螺环原碳酸酯单体：３，９－二（对甲氧基苄基）－１，５，７，１１－四氧杂螺环［５，５］十一烷。以ＢＦ３·ＯＥｔ２为催化剂，实现了其阳离子聚合。聚合产物的＾１Ｈ ＮＭＲ、＾１３Ｃ ＮＭＲ、ＩＲ及元素分析均表明发生了双开环聚合反应。探讨了其聚合历程。用ＤＳＣ和ＩＲ跟踪环氧树脂及其与螺环单体混合后的固化反应过程，研究了固化剂、反应条件对固化反应的影响。     

Synthesis and radical polymerization of spiro orthocarbonates bearing exomethylene groups

Synthesis and radical polymerization of spiro orthocarbonates (SOCs) bearing exomethylene groups at the α to the ether oxygen ( 1a–1e ) were studied. SOCs 1a–1e were prepared by the successive reactions of dichlorodiphenoxymethane with two different diols followed by dehydrochlorination. Radical polymerization of the SOCs was carried out in the presence of an appropriate initiator (3 mol % versus monomer) at 130 and 180°C. The obtained polymer insoluble in n-hexane contained both vinyl polymerization unit 13 and double ring-opening polymerization unit 14 (ketone-carbonates). The degree of ring-opening followed the order: 1a <1b < 1d, 1e . n-Hexane-insoluble polymer was not obtained in the polymerization of 1c . Both steric hindrance of methyl group and ring size affected the degree of ring-opening. The introduction of methyl group into SOC increased the degree of ring-opening ( 1a <1b ), whereas the degree of ring-opening of either 1d , consisting of six- and seven-membered rings, and 1e , consisting of two seven-membered rings, was higher than those of 1a and 1b , consisting of five and seven-membered rings. From the molecular orbital calculation (PM3, UHF method), it was concluded that if the first single ring-opening occurs, then the successive second ring-opening takes place more smoothly. The first ring-opening requires more energy than the vinyl polymerization does. © 1994 John Wiley & Sons, Inc.     

Prediction of polymerization shrinkage using molecular modeling

Group interaction modeling (GIM) is used to predict the changes in the volume and, therefore, shrinkage of a wide variety of commonly encountered acrylate and methacrylate monomers during polymerization. The predictions of the model are in excellent agreement with experimental data available in the literature. It is demonstrated that, given appropriate estimations of the ultimate matrix morphology, GIM can be used to give estimates of polymerization shrinkage in three‐dimensional crosslinked polymer networks that relate well to experimental data available for dental composite matrices. GIM provides a very useful framework within which the phenomenon of polymerization shrinkage can be considered. The approach challenges certain common misconceptions relating conversion to shrinkage. The limitations of this approach are discussed, and targets for future research are clearly outlined that could extend the scope of this methodology to encompass novel systems for which morphological information is not available. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 528–548, 2003     

Free radical ring‐opening polymerization of cyclic allylic sulfides: Liquid monomers with low polymerization volume shrinkage

The free radical polymerization of four methylated cyclic allylic sulfides was examined with reference to their polymerization volume shrinkage and the effect of ring size on reactivity. The compounds examined were 2‐methyl‐5‐methylene‐1,3‐dithiane ( 5 ) (solid), 2‐methyl‐6‐methylene‐1,4‐dithiepane ( 6 ) (liquid), 6‐methyl‐3‐methylene‐1,5‐dithiacyclooctane ( 7 ) (liquid), and 6,8‐dimethyl‐3‐methylene‐1,5‐dithiacyclooctane ( 8 ) (liquid). The monomers were stable materials not requiring any special handling or storage conditions. They were polymerized in bulk using thermal azobisisobutyronitrile (AIBN, VAZO88) and photochemical initiators (Ciba DAROCUR 1173) and in benzene solutions (AIBN, 70 °C). The six‐membered ring monomer 5 was unreactive whereas seven‐membered ring monomer 6 polymerized to high conversion in bulk. In addition, 6 did not polymerize in benzene solution at 70 °C at [ 6 ] = 1.25M. Eight‐membered ring monomers 7 and 8 polymerized in bulk to complete conversion with thermal and photochemical initiators to give lightly crosslinked materials. Near complete conversion to soluble polymers could be obtained in solution polymerizations in benzene. Soluble polymers were also obtained in photochemical initiated bulk polymerizations by lowering initiator concentrations or length of irradiation. The methyl substituent had no effect on which allylic carbon–sulfur bond fragmented in the ring‐opening step. The polymerization volume shrinkages of monomers 7 and 8 were 1.5 and 2.4% respectively and together with monomer 4 (1.5–2.0% shrinkage) are the best available liquid free radical ring‐opening monomers that can be polymerized in bulk at room temperature. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 202–215, 2001     

Synthesis of dendritic–linear block copolymers by living ring-opening polymerization of lactones and lactides using dendritic initiators

Polyether dendrons have been successfully used as macroinitiators for the living ring-opening polymerization (ROP) of lactones and lactides. A hydroxyl group located at the focal point of dendrimers of different generations was transformed into diethyl aluminum alkoxides by reaction with triethyl aluminum. The dendritic aluminum alkoxides proved to be efficient macroinitiators for the living ROP of ε-caprolactone (εCL), 1,4,8-trioxa(4,6)spiro[9]undecanone (TOSUO), D ,L - and L ,L -lactide. Formation of these block copolymers of unusual macromolecular architecture was supported by size exclusion chromatography and spectroscopy. The versatility of this synthetic approach allowed ω-functional dendrimer block-polyesters, such as macromonomer, and macromolecules with novel architectures, to be prepared. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1923–1930, 1999     

Detailed study of the ring-opening metathesis polymerization of norbornene bearing a five- or six-membered ring cyclic carbonate along with volume expansion

The ring-opening metathesis polymerization (ROMP) of norbornene derivatives bearing five- or six-membered cyclic carbonate ( 2 or 3 ) was carried out with a typical ruthenium catalyst [bis(tricyclohexylphosphine)benzylidene ruthenium(IV) dichloride], the so-called first-generation Grubbs catalyst, under various reaction conditions, to smoothly obtain the corresponding polyalkenamers ( 5 and 6 ) along with volume expansion. The number-average molecular weights (M_n's), 10% weight loss decomposition temperatures, glass-transition temperatures (T_g's), and volume expansion ratios of the resulting products depended on the polymerization conditions. The degree of volume expansion was mainly affected by M_n, T_g, and the cis/trans configuration of the exocyclic double bonds of the resulting polymers. The volume expansion was confirmed to specifically occur during the polymerization of the monomer bearing cyclic carbonate moieties, and similar ROMPs of monomers without cyclic carbonate, such as norbornene itself, the monomer 5,5-bis(methoxymethyl)bicyclo[2.2.1]hept-2-ene, and the monomer endo-N-methylbicyclo[2.2.1]hept-5-ene-2,3-dicarboxylimide, proceeded along with volume shrinkage. Furthermore, an investigation of another type of polymerization, a vinyl-type one, of monomer 2 suggested that the volume expansion specifically took place in the ring-opening type of polymerization. In addition, the Sc(OTf)₃-mediated cationic ring-opening reaction of the cyclic carbonate moiety of polyalkenamer 5 smoothly proceeded along with volume expansion or nearly zero volume shrinkage to yield the corresponding networked polymer. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 395–405, 2006     

Ring-opening polymerization of cyclobutane adducts of tetracyanoethylene and vinyl ethers with tertiary amines

Ring-opening polymerizations of cyclobutane adducts of tetracyanoethylene (TCNE) and vinyl ethers (VE) or p-methoxystyrene with tertiary amines are described. The polymerization of the cyclobutane adduct 1a of TCNE and ethyl vinyl ether (EVE) was carried out with 10 mol % of triethylamine in acetonitrile at ambient temperature to afford the alternating copolymer of TCNE and EVE with high molecular weight in good yield under various conditions. Under the optimum condition, the cyclobutane adducts of TCNE and a variety of VEs such as n-butyl vinyl ether, isobutyl vinyl ether, 2,3-dihydrofuran, and 3,4-dihydro-2H-pyran were polymerized to yield similar polymers. Although the cyclobutane adduct 4 of TCNE and p-methoxystyrene did not polymerize under these conditions, the treatment of 4 with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in acetonitrile at 60°C gave the polymer. On the basis of the fact that the polymer molecular weight increased rapidly at the initial stage and slowly even after the consumption of all of monomers, we propose that the tertiary amine initiates the chain anionic polymerization of the cyclobutane adduct to afford an ammonium macrozwitterion 3 , which is subjected to the intermolecular nucleophilic substitution with each other in a step polymerization manner. © 1995 John Wiley & Sons, Inc.     

Synthesis and ring-opening polymerization of new 1,4-anhydro-glucopyranose derivatives

Three new 1,4-anhydro-glucopyranose derivatives having different hydroxyl protective groups such as 1,4-anhydro-2,3,6-tri-O-methyl-α-D -glucopyranose (AMGLU), 1,4-anhydro-6-O-benzyl-2,3-di-O-methyl-α-D -glucopyranose (A6BMG), and 1,4-anhydro-2,3-di-O-methyl-6-O-trityl-α-D -glucopyranose (A6TMG) were synthesized from methyl α-D -glucopyranoside in good yields. Their polymerizability was compared with that of 1,4-anhydro-2,3,6-tri-O-benzyl-α-D -glucopyranose (ABGLU) reported previously. The trimethylated monomer, AMGLU, was polymerized by a PF₅ catalyst to give 1,5-α-furanosidic polymer having number-average molecular weights (M̄_n) in the range of 2.8 × 10³ to 6.8 × 10³. The ¹³C-NMR spectrum was compared with that of methylated amylose and cellulose. Other anhydro monomers, A6BMG and A6TMG, gave the corresponding 1,5-α furanosidic polymers having M̄_n = 17.1 × 10³ and 1.8 × 10³, respectively. Thus, the substituents at the C2 and C6 positions were found to play an important role for the ring-opening polymerizability of the 1,4-anhydro-glucose monomers. In addition, debenzylation of the tribenzylated polymer gave free (1 → 5)-α-D -glucofuranan. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 841–850, 1998     

Bis(pyrrolide-imine) Ti complexes with MAO: A new family of high performance catalysts for olefin polymerization

This contribution reports on the syntheses, structures and olefin polymerization behavior of Ti complexes having a pair of chelating pyrrolide-imine [N⁻,N] ligands. X-ray analyses as well as ¹H NMR studies demonstrate that bis(pyrrolide-imine) Ti complexes (named PI Catalysts) contain approximately octahedrally coordinated metal centers with mutually trans-pyrrolide-Ns, cis-imine-Ns and cis-Cls. DFT studies suggest that PI Catalysts, when activated, provide a metal alkyl in the cis position to a vacant coordination site for monomer binding. These theoretical studies also show that the active species derived from PI Catalysts normally possess higher electrophilicity and a sterically more open nature compared with those produced using bis(phenoxy-imine) Ti complexes (Ti-FI Catalysts) which are known as high performance olefin polymerization catalysts. These structural as well as electronic features suggest that PI Catalysts have high potential for the polymerization of olefinic monomers.Unlike high performance Ti-FI Catalysts, PI Catalysts do not require the presence of steric bulk in close proximity to the anionic donor. PI Catalysts combined with MAO display high ethylene polymerization activities (max. 33,200 kg-polymer/mol-cat/h, 25 °C, atmospheric pressure) comparable to those obtained with early group 4 metallocene catalysts (e.g., Cp₂TiCl₂ 16,700 kg-polymer/mol-cat/h) under identical conditions. As expected, PI Catalysts exhibit higher incorporation capability for propylene and 1-hexene relative to FI Catalysts though the incorporation levels are lower than those for Cp₂TiCl₂. To our surprise, PI Catalysts/MAO show remarkably high norbornene (NB) incorporation, superior to that seen with the [Me₂Si(Me₄Cp)N-tBu]TiCl₂ (CGC) catalyst system, and they readily form ethylene-NB copolymers with high NB contents. The highly electrophilic and sterically open nature is probably responsible for the high NB affinity. Additionally, PI Catalysts/MAO possess characteristics of living ethylene polymerization (though under limited conditions) and afford high molecular weight PEs with very narrow molecular weight distributions (M_n 225,000, M_w/M_n 1.15, 10-s polymerization, 25 °C). Moreover, these catalysts can copolymerize ethylene and NB in a highly controlled living manner to afford monodisperse alternating copolymers with very high molecular weights (M_n > 500,000, M_w/M_n < 1.2) at room temperature. This unique living nature allows the preparation of a number of ethylene- and NB-based block copolymers, including PE-b-poly(ethylene-co-NB) and poly(ethylene-co-NB)_a-b-poly(ethylene-co-NB)_b, in which each segment contains a different NB content. These are probably the first examples of the syntheses of block copolymers from ethylene and NB. Consequently, the discovery and application of PI Catalysts has exercised a significant influence on olefin polymerization catalysis and polymer synthesis.     

化学酶法合成五嵌段聚合物及其自组装行为的研究

用酶促开环聚合与ATRP方法相结合,制备了聚甲基丙烯酸六氟丁酯-聚己内酯-聚乙二醇-聚己内酯-聚甲基丙烯酸六氟丁酯(PHFMA-b-PCL-b-PEG-b-PCL-b-PHFMA)五嵌段聚合物.首先用Novozym e 435作为催化剂合成了聚己内酯-聚乙二醇-聚己内酯三嵌段聚合物,然后通过端基官能化法合成了大分子引发剂,并用其引发甲基丙烯酸六氟丁酯(HFMA)的ATRP反应,合成了五嵌段聚合物.通过核磁和GPC证明了大分子引发剂和五嵌段共聚物的结构,五嵌段共聚物的GPC分析表明这种合成方法的可行.共聚物胶束的直径和大小通过动态光散射方法和原子力显微镜测试,五嵌段共聚物在水中的的自组装行为也被研究.结果证明胶束是球形,其平均直径为77 nm.聚合物在四氢呋喃中的浓度对聚合物的聚集形貌有很大的影响.     

Synthesis and characterization of graft copolymers based on polyepichlorohydrin via reversible addition-fragmentation chain transfer polymerization

In this study, synthesis of poly(epichlorohydrin-g-methyl methacrylate) graft copolymers by reversible addition-fragmentation chain transfer (RAFT) polymerization was reported. For this purpose, epichlorohydrin was polymerized by using HNO₃ via cationic ring-opening mechanism. A RAFT macroinitiator (macro-RAFT agent) was obtained by the reaction of potassium ethyl xanthogenate and polyepichlorohydrin. The graft copolymers were synthesized using macro-RAFT agent as initiator and methyl methacrylate as monomer. The synthesis of graft copolymers was conducted by changing the time of polymerization and the amount of monomer-initiator concentration that affect the RAFT polymerization. The effects of these parameters on polymerization were evaluated via various analyses. The characterization of the products was determined using ¹H-nuclear magnetic resonance (¹H-NMR), Fourier-transform infrared spectroscopy, gel-permeation chromatography, thermogravimetric analysis, elemental analysis, and fractional precipitation techniques. The block lengths of the graft copolymers were calculated by using ¹H-NMR spectrum. It was observed that the block length could be altered by varying the monomer and initiator concentrations.     

螺环单体的合成、聚合及与环氧树脂的固化反应

合成了新螺环原碳酸酯单体：３，９－二（对甲氧基苄基）－１，５，７，１１－四氧杂螺环［５，５］十一烷．以ＢＦ３·ＯＥｔ２为催化剂，实现了其阳离子聚合．聚合产物的１ＨＮＭＲ、１３ＣＮＭＲ、ＩＲ及元素分析均表明发生了双开环聚合反应．探讨了其聚合历程．用ＤＳＣ和ＩＲ跟踪环氧树脂及其与螺环单体混合后的固化反应过程，研究了固化剂、反应条件对固化反应的影响     

Ring-opening polymerization of cyclobutane adduct of dimethyl 1,1-dicyanoethylene-2,2-dicarboxylate and ethyl vinyl ether

For an extension of the work on the ring-opening polymerizations of cyclobutane adducts of strong donor olefins and strong acceptor olefins yielding novel alternating copolymers of those olefins, the ring-opening polymerization of the cyclobutane adduct 3 of dimethyl 1,1-dicyanoethylene-2,2-dicarboxylate (DDED) and ethyl vinyl ether (EVE) is investigated. Cyclobutane 3 reacted with methanol and acetic acid at ambient temperature to yield the corresponding ring-opened adducts. The polymerizations of 3 were carried out with anionic initiators, tertiary amines, ammonium halides, and Lewis acids, respectively, according to the polymerization methods of the cyclobutane adduct 1 of tetracyanoethylene (TCNE) and EVE. All these polymerization catalysts except for ammonium halides were effective for the polymerization of 3 , yielding alternating copolymers of DDED and EVE. The chain transfer reactions of the polymerization with anionic initiators are also discussed on the basis of a model reaction. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1563–1570, 1997     

Coordinate anionic ring-opening polymerization of oxetanes with aluminum benzyl alcoholate bis(2,6-di-tert-butyl-4-methylphenolate)

Aluminum benzyl alcoholate bis(2,6-di-tert-butyl-4-methylphenolate) (BnOAD), which was prepared through the mixing of equimolar amounts of benzyl alcohol and methylaluminum bis(2,6-di-tert-butyl-4-methylphenolate) (MAD), successfully polymerized four-membered cyclic ethers in a coordinate anionic ring-opening manner. The polymerization of 3-(4-bromobutoxymethyl)-3-methyloxetane (OxBr) with 5 mol % BnOAD proceeded slowly in toluene at 25 °C and produced sufficiently high-molecular-weight poly(OxBr) in a moderate yield in 24 h. The polymerization was greatly accelerated by the addition of a sterically hindered Lewis acid such as MAD, and this resulted in a nearly quantitative polymer yield within 24 h. In sharp contrast, conventional cationic polymerization with boron trifluoride etherate as a typical Lewis acid initiator produced low-molecular-weight poly(OxBr) along with a substantial amount of the cyclic tetramer. The polymerization of the simplest unsubstituted oxetane with BnOAD resulted in failure. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4570–4579, 2004     

Effect of oligo(spiroorthocarbonate)s on the volume shrinkage of epoxides during crosslinking by sulfonium salt‐initiated cationic polymerization of epoxides

Oligo(spiroorthocarbonate)s 1 , which were synthesized by the polycondensation of pentaerythritol derivatives with tetraethylorthocarbonate, were employed as comonomers in the cationic polymerization of epoxide initiated by sulfonium salt. In the copolymerization, the spiroorthocarbonate moiety of 1 underwent double ring‐opening reaction, leading to the efficient diminution of the volume shrinkage upon the copolymerization. Thermal properties of the resulting networked polymers were evaluated by TGA. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1564–1568     

Preparation and Characterization of Linear and Miktoarm Star Side-Chain Liquid Crystalline block Copolymers with p-Methoxyazobenzene Moieties via a Combination of ATRP and ROP

One linear and two miktoarm star side-chain liquid crystalline (LC) block copolymers with p-methoxyazobenzene moieties were prepared by a combination of ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP) techniques. First, ROPs of ε -caprolactone (ε -CL) were carried out catalyzed by Sn(Oct)₂ using three multifunctional initiators, hydroxyethyl 2-bromoisobutyrate (AB type), 3-hydroxy-2-(hydroxymethyl)-2-methylpropyl 2-bromo-2-methylpropanoate (A₂B type) and 2,2-bis(hydroxymethyl)propane-1,3-diyl bis(2-bromo-2-methylpropanoate) (A₂B₂ type), at 110°C in toluene, respectively. Second, the previously obtained poly(ε -caprolactone)s (PCLs) with bromines functionalities were used as the macroinitiators to conduct ATRP of 6-(4-methoxy-4-oxy-azobenzene) hexyl methacrylate (MMAZO) with CuBr/PMDETA as the catalyst systems at 85°C in anisole to prepare the linear and miktoarm side-chain LC block copolymers (PCL-b-PMMAZO, (PCL)₂-(PMMAZO) and (PCL)₂-(PMMAZO)₂). The produced polymers were well-controlled with the controlled molecular weights and the relatively narrow molecular weight distributions (M _w/M _n ≤ 1.35). The structures of the obtained polymers were all characterized by NMR, FT-IR and GPC analysis. Furthermore, the LC properties of the linear and miktoarm star block copolymers were also investigated by differential scanning calorimetry (DSC) and thermal polarized optical microscopy (POM).     

Synthesis and cationic ring-opening polymerization of mono- and bifunctional spiro orthoesters containing ester groups and depolymerization of the obtained polymers: An approach to chemical recycling for polyesters as a model system

A spiro orthoester having an ester moiety, 2-acetoxymethyl-1,4,6-trioxaspiro[4.6]undecane (4) was synthesized, and its cationic polymerization and depolymerization of the obtained polymer (5) were carried out. The monomer 4 underwent cationic polymerization with a cationic catalyst to afford the corresponding poly(cyclic orthoester) 5. The obtained polymer 5 could be depolymerized with a cationic catalyst to regenerate the monomer 4 in an excellent yield. Further, bifunctional spiro orthoesters (6, 8, 9) having diester moieties were synthesized from terephthalic acid, succinic acid, and 1,4-cyclohexanedicarboxylic acid, and their acid-catalyzed reversible crosslinking–decrosslinking was examined. The bifunctional monomer 6 derived from terephthalic acid underwent cationic crosslinking to afford the corresponding network polymer (7), which could be also depolymerized to regenerate the original bifunctional monomer 6. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2551–2558, 1999