含异氰脲酸酯结构聚醚多元醇的合成

以1,3,5-三羟乙基异氰脲酸酯(THEIC)为引发剂、三氟化硼乙醚络合物为催化剂,环氧化合物为环单体,进行了阳离子开环聚合反应的研究.发现THEIC与环氧单体可在非均相体系中平稳地进行阳离子开环聚合反应.在THEIC体系,就链引发而言,环氧氯丙烷的大于环氧丙烷、丁基醚环氧乙烷.调整环单体加料次序就可以获得嵌段共聚醚多元醇.     

Synthesis of novel highly reactive silicone-epoxy monomers for cationic photopolymerizations

A series of novel cationically photopolymerizable silicone-epoxide monomers bearing substituted benzyl ether groups were prepared. Monomers with methoxy groups on the aromatic ring of the benzyl ether group were synthesized by sequential hydrosylation reactions of 1,1,3,3-tetramethyl disiloxane. Kinetic studies using real-time infrared spectroscopy of the cationic photopolymerizations of these novel monomers showed that those monomers with methoxy groups exhibited elevated rates of photopolymerization. The acceleration effect was explained on the basis of synergistic effects of two mechanisms, namely, the normal ring opening polymerization catalyzed by a Brönstead acid, and the cationic photopolymerization induced by the redox interaction between the free radicals formed in the backbone of the monomer and the onium salt used as photoinitiator. The methoxy groups on the aromatic ring of the benzyl ether enhance the stabilization of the carbocation formed in the structure of the monomer. Silicone-epoxy monomer with 2,5-dimethoxybenzyl ether group exhibited the higher photopolymerization rate. The latter compound can also be used as accelerator of the cationic photopolymerization of commercial silicone-epoxy monomer when used in low concentrations.     

Redox Initiated Cationic Polymerization: Reduction of Triarylsulfonium Salts by Silanes

A novel redox initiator system for carrying out the cationic polymerization of epoxide, oxetane and vinyl ether monomers has been developed. The redox couple is based on a triarylsulfonium salt as the oxidant with an organosilane as the reducing agent. The reaction between these two agents is markedly catalyzed by platinum and palladium complexes. Cationic polymerizations using this redox initiator system were carried out in a conventional manner with neat monomer or under solution conditions. This paper also describes the novel use of a two-component redox system in which the silane is delivered to the monomer sample in the vapor state. Optical pyrometry (infrared thermography) was employed as a convenient method with which to monitor the polymerizations. A study of the effects of variations in the structures of the triarylsulfonium salt, the silane and the type of noble metal catalyst were carried out. The use of this initiator system for carrying out commercially attractive cross-linking polymerizations for coatings, composites and electronic encapsulations is discussed.     

Design of network polymers by photopolymerization

The base and transition metal catalyzed isomerization of allyl and crotyl ethers affords a facile, high yield route to the preparation of a variety of mono-, di-, and multifunctional 1-propenyl and 1-butenyl ethers. Employing this novel method, monomers containing epoxide, ester, ether carbonate and urethane groups can be prepared from their readily available allyl and crotyl precursors. In general, these monomers display very high reactivity in cationic polymerizations. In our work, we have focused on photoinduced cationic polymerizations of these monomers using diaryliodonium and triarylsulfonium salt photoinitiators. To study these very fast photopolymerizations, extensive use of real-time infrared spectroscopy was made. Employing this technique, the effects of monomer and photoinitiator structure on the rates of polymerization were studied.     

UV curing of epoxy functional hybrid silicones

Several epoxy difunctional hybrid alkylene‐silicone telomers with different silicone characters and organic spacers (linkers) were prepared via the platinum‐catalyzed polyhydrosilylation of α,ω‐dihydrosiloxanes and α,ω‐dienes. Thereafter, the resulting Si? H‐terminated prepolymers were terminally functionalized with 4‐vinyl‐1,2‐epoxycyclohexane or allyl glycidyl ether. In the presence of a lipophilic cationic photoinitiator, the terminally epoxy‐functionalized hybrid alkylene–silicone telomers were photopolymerized to give crosslinked, soft, elastomeric, and transparent films. The progress of the photoinitiated cationic ring‐opening epoxide polymerizations was monitored using optical pyrometry. Potential applications for these novel photocurable epoxy‐functional telomers are as modifiers for UV curable coatings, printing inks, adhesives, and release coatings. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Novel piperidinium salts as latent initiators for cationic polymerization of epoxide and vinyl ether

Novel dibenzylpiperidinium salts with nonnucleophilic anions (DBPi‐SbF₆, DBPi‐PF₆) have been prepared as latent cationic initiators. Utility of these salts in the photo and thermal‐induced cationic polymerizations of epoxide and vinyl ether monomer systems has been studied. The new initiator, DBPi‐SbF₆ showed good solubility, high reactivity, and high thermal latency for polymerizations of epoxide and vinyl ether monomers with only 1 wt % of concentration. Cationic polymerization of vinyl ether monomer was significantly faster than epoxide monomer by the synthesized initiators. This article describes the synthesis, characterization, and activity of novel initiators. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

UV‐initiated free radical and cationic photopolymerizations of acrylate/epoxide and acrylate/vinyl ether hybrid systems with and without photosensitizer

Various properties of UV‐initiated acrylate/epoxide and acrylate/vinyl ether hybrid photopolymerizations with and without photosensitizer in the presence of free radical and cationic‐type photoinitiators have been determined by dynamic mechanical thermal analysis (DMTA), calorimetric analysis (photodifferential scanning calorimetry, photo‐DSC; and differential scanning calorimetry), and scanning electron microscopy. DMTA experiments revealed that the UV curing of hybrid systems may produce interpenetrating polymer networks. Photo‐DSC analyses indicated that the acrylates polymerized faster than the epoxide and vinyl ether in the hybrid systems; the addition of a photosensitizer, isopropylthioxanthone (ITX), increased the polymerization rate of the epoxide and vinyl ether in the hybrid systems. SEM analysis confirmed that the free radical system seemed to be significantly affected by oxygen inhibition, while the cationic and hybrid systems were not nearly inhibited by oxygen; the presence of photosensitization produced by the addition of ITX enhanced the surface curing of the hybrid systems. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1473–1483, 2004     

Investigation of the photoactivated frontal polymerization of oxetanes using optical pyrometry

An investigation of the photoactivated cationic ring-opening frontal polymerization of a series of 3,3-disubstituted oxetanes was carried out with the aid of a novel technique, optical pyrometry. Using this technique, the effects of various experimental parameters such as photoinitiator type and concentration, light intensity and sample configuration as well as the effects of monomer structure on the frontal behavior of these monomers were examined. Upon photoactivation with UV light, 3,3-disubstituted oxetanes display a long dormant period at room temperature as the result of the formation of metastable tertiary oxonium ions. Only small amount of thermal activation energy is required to induce the further reaction of these species with resulting exothermic autoaccelerated ring-opening polymerization. Frontal polymerization was observed for both mono- and difunctional oxetane monomers and the velocity of propagation of a given monomer was found to be related to its oxetane equivalent weight.     

Quinoxaline derivatives as long wavelength photosensitizers in photoinitiated cationic polymerization of diaryliodonium salts

The present paper is focused on visible light initiated cationic polymerizations. Photoinitiated polymerization of representative vinyl ether and oxirane monomers using two quinoxaline derivatives; namely (2-(2,3-dihydrobenzo [b][1,4]dioxin-6-yl)-3-(2,3-dihydrobenzo[b]-[1,4]dioxin-7-yl)-5-(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-8-(2,3-dihydrothieno[3,4-b][1,4]dioxin-7yl) quinoxaline) (DBQEd) and 2,3,5,8-tetra(thiophen-2-yl)quinoxaline (TTQ) are studied. Novel dyes based on the quinoxaline skeleton are employed as efficient photosensitizers in cationic photopolymerizations. Polymerizations were initiated at room temperature upon irradiation with long-wavelength UV and visible lights in the presence of diphenyliodonium hexafluorophosphate (Ph₂I⁺PF₆^?). The progress of the polymerizations was monitored by optical pyrometry (OP). Solar irradiation is also employed to carry out the cationic polymerization of a diepoxide monomer in the presence of air.     

Synthesis and modification of epoxy‐ and hydroxy‐functional microspheres

This article describes the synthesis and surface modification of epoxy‐ and hydroxy‐functional polymeric microspheres. The functionalized microspheres were synthesized using aqueous and nonaqueous cationic suspension photopolymerizations using multifunctional silicon‐containing epoxy monomers with iodonium salt photoinitiators. Although generally solid microspheres were obtained using these techniques, macroporous spheres could be obtained though the use of porogens. Various rapid and facile acid‐ and base‐catalyzed ring‐opening addition reactions were performed on the epoxy‐functional microspheres. These reactions include the additions of mercaptans, acid chlorides, isocyanates, amines, sodium azide, water, and alcohols. Similar functionalization reactions were performed on the hydroxy‐functional microspheres. The particle size and size distribution were determined using scanning electron microscopy. Fourier transform infrared spectroscopy was used to monitor the functionalization reactions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1574–1585, 2005     

Synthesis and polymerizations of novel bisphosphonate‐containing methacrylates derived from alkyl α‐hydroxymethacrylates

The synthesis and polymerizations of four novel bisphosphonate‐containing monomers are reported. The monomers were synthesized from reaction of ethyl and tert‐butyl α‐bromomethacrylates with 3,3‐bis(diethoxyphosphoryl)propanoic acid or with tetraethyl 4‐hydroxybutane‐1,1‐diyldiphosphonate. Their thermal bulk polymerizations, photopolymerizations and copolymerizations with poly(ethylene glycol) methyl ether methacrylate were investigated. The homopolymerizations resulted in polymers with values of 25 000–83 000 g mol^?1; the copolymerizations yielded soluble polymers with 22–34% incorporation of the new monomers; the photopolymerizations gave some structure–reactivity correlation; and one of the homopolymers, upon hydrolysis of its bisphosphonate groups, could interact with hydroxyapatite. © 2013 Society of Chemical Industry     

不同官能度环氧树脂的阳离子光固化研究

对4种不同官能度的环氧树脂在紫外光辐照下用一种二苯基碘钅翁盐或两种二烷基苯甲酰锍盐光引发剂进行阳离子光固化的体系作了系统的研究。研究结果表明,二氨基二苯甲烷环氧树脂AG-80不能阳离子光固化,而E-51,711和TDE-85均可在二苯基碘钅翁六氟磷酸盐或1-甲基-1-十二烷基苯甲酰甲基六氟锑酸锍盐作用下进行紫外光引发阳离子聚合,其中二苯基碘钅翁六氟磷酸盐引发E-51环氧树脂阳离子光固化的效果最好,该树脂体系可用做紫外光固化复合材料的树脂基体。研究还发现,在停止紫外光辐照后,由于阳离子聚合链终止困难而使碘钅翁盐引发的环氧树脂光固化体系存在后固化现象,后固化速度与后固化时的温度有关。     

Kinetic studies of cationic photopolymerizations of cycloaliphatic epoxide,triethyleneglycol methyl vinyl ether,and cyclohexene oxide

The cationic photopolymerizations of monofunctional monomers and cycloaliphatic diepoxide monomer were examined in detail. Phenomenological kinetic models were developed for photopolymerizations of the monofunctional and difunctional monomers. For monofunctional monomers, the nonlinear models gave an excellent fit to the experimental data. Although a second‐order autocatalytic model was shown to be invalid above 10% conversion for the polymerization of a difunctional monomer (3,4‐epoxycyclohexylmethyl‐3′,4′‐epoxycyclohexane carboxylate, ECH), an autocatalytic model using diffusion‐controlled reaction with a Williams‐Landel‐Ferry (WLF) equation fits the experimental data well over the entire conversion range. A mechanistic model based on the free volume theory was also developed for cationic polymerization of the cycloaliphatic di‐epoxide monomer by using the method of moments. The model gives a good fit for the conversion and M_w development, but the calculated M_n results are lower than the experimental values. POLYM. ENG. SCI., 45:1546–1555, 2005. © 2005 Society of Plastics Engineers     

Dithioester functionalization of poly(cyclohexene oxide) and its application to obtain block copolymers

A new method of introducing dithioester groups into the polymer chain of poly(cyclohexene oxide) is reported. It includes the use of diaryliodonium salt and an aromatic dithioacid as a redox couple to initiate the cationic polymerization of cyclohexene oxide. It was found that the dithioacid by itself cannot start the polymerization of cationic polymerizable monomers; however, in combination with a diaryliodonium salt, an exothermic reaction was produced, yielding a thiocarbonylthio‐functionalized polyether. Thermal profiles of the redox polymerizations were determined by means of optical pyrometry. A preliminary study showed that when the poly(cyclohexene oxide) functionalized with dithioester groups was introduced into the radical polymerization of styrene, the polystyryl growing radicals reacted with the dithioester‐functionalized polyether to form a block polymer. The amount of polyether actually incorporated into the block copolymer was calculated to be 70% of the initial amount of poly(cyclohexene oxide)/dithiobenzoic acid charged into the reactor. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and photo‐curing behaviors of silicon‐containing (vinyl ether)–(allyl ether) hybrid monomers

A series of silicon‐containing (vinyl ether)–(allyl ether) hybrid monomers used in nano‐imprint lithography resists were synthesized and subjected to photo‐initiated polymerization. The surface energies of the monomers and the resulting polymer films were then investigated. The surface energies of the monomers were very low at less than 15 mJ m^–2. The photo‐curing behaviors of the five hybrid monomers were investigated using real‐time Fourier transform infrared spectroscopy. The monomers were sequentially initiated with cationic (PAG201) and mixed (cationic initiator PAG201, radical initiator ITX or TPO) initiators. The vinyl ether double bond polymerized both rapidly and completely, whereas the allyl ether double bond remained when PAG201 was used as the photo‐initiator and polymerized completely with mixed initiators. The different double bonds of the silicon‐containing (vinyl ether)–(allyl ether) hybrid monomer increased the efficiency of the polymerization and overcame the intrinsic limitations of the free radical and cationic polymerization processes, including strong oxygen inhibition, large volume shrinkage and high humidity sensitivity. The five monomers with low viscosity, low surface energy, good thermal stability and good photo‐polymerization properties were suitable for nano‐imprint photoresists. © 2013 Society of Chemical Industry     

Ring‐opening bulk polymerization of five‐ and six‐membered cyclic phosphonates using maghnite,a nontoxic proton exchanged montmorillonite clay

A new method of preparation of poly(alkylene H‐phosphonate)s by ring‐opening bulk polymerization of the five‐ and six‐membered cyclic phosphonates monomers using the nontoxic Maghnite‐H⁺ as the initiator is described. Cyclic phosphonate monomers have been first synthesized. In particular, a new one‐step synthesis of 2‐hydro‐2‐oxo‐1,3,2‐dioxaphospholane is reported with a yield of 70%. The efficiency of the montmorillonite sheet silicate clay which exchanged with protons, called Maghnite‐H⁺, as cationic initiator has been proved and the resulting biomimetic poly(alkylene H‐phosphonate)s have been characterized. The Maghnite‐H⁺ regenerated after one turn‐over has showed to be still efficient as initiator for the ring‐opening polymerization. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effects of monomer and ether structure on metal-free living cationic polymerization of various vinyl ethers using hydrogen chloride with ether

A highly effective initiating system has been achieved for living cationic polymerization of vinyl ethers consisting of HCl alone without Lewis acid. This system is a facile metal-free living cationic polymerization using no HCl/Lewis acid but the already adopted complex HCl·Et₂O. In this study, we investigated the effects of a monomer and ether structure on the polymerization behavior. The monomers are classified into three kinds of monomers: alkyl vinyl ether, vinyl ether with electron-donating groups in the pendant, and vinyl ether with bulky group next to the electron-donating substituent in the pendant. The HCl·Et₂O systems were applicable for the polymerizations of all vinyl ethers used. However the structure around electron-donating groups in the pendant of monomer affected the polymerizations rate and induction period. The initiation reactions can be successfully achieved using ether effectively dissociating HCl, especially symmetrical ether.     

Volume‐expandable monomer 5,5‐dimethyl‐1,3‐dioxolan‐2‐one: Its copolymerization behavior with epoxide and its applications to shrinkage‐controlled epoxy‐curing systems

The copolymerization of epoxides and a six‐membered cyclic carbonate, 5,5‐dimethyl‐1,3‐dioxan‐2‐one (DM6CC), was carried out with 1,8‐diazabicyclo[5.4.0]undec‐7‐ene as an initiator. In the copolymerization of glycidyl phenyl ether (GPE) and DM6CC, DM6CC remarkably accelerated the polymerization rate of GPE and also effectively suppressed chain‐transfer reactions, which occur in the homopolymerization of the epoxide. This suppression resulted in the formation of the corresponding copolymer with a higher molecular weight. Similar effects of DM6CC were also observed in a curing system with a Novolac‐type multifunctional epoxide (Novolac glycidyl ether). The curing reaction of the epoxide in the presence of DM6CC smoothly proceeded and yielded the corresponding networked polymer, showing a decrease in the volume shrinkage as the DM6CC content increased. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 372–378, 2005     

Synthesis and characterization of homo‐ and copolymers of 3‐(2‐cyano ethoxy)methyl‐ and 3‐[methoxy(triethylenoxy)]methyl‐3′‐methyl‐oxetane

Two oxetane‐derived monomers 3‐(2‐cyanoethoxy)methyl‐ and 3‐(methoxy(triethylenoxy)) methyl‐3′‐methyloxetane were prepared from the reaction of 3‐methyl‐3′‐hydroxymethyloxetane with acrylonitrile and triethylene glycol monomethyl ether, respectively. Their homo‐ and copolyethers were synthesized with BF₃· Et₂O/1,4‐butanediol and trifluoromethane sulfonic acid as initiator through cationic ring‐opening polymerization. The structure of the polymers was characterized by FTIR and¹H NMR. The ratio of two repeating units incorporated into the copolymers is well consistent with the feed ratio. Regarding glass transition temperature (T_g), the DSC data imply that the resulting copolymers have a lower T_g than pure poly(ethylene oxide). Moreover, the TGA measurements reveal that they possess in general a high heat decomposition temperature. The ion conductivity of a sample (P‐AN 20) is 1.07 × 10^?5 S cm^?1 at room temperature and 2.79 × 10^?4 S cm^?1 at 80 °C, thus presenting the potential to meet the practical requirement of lithium ion batteries for polymer electrolytes. Copyright © 2005 Society of Chemical Industry     

Cationic activated monomer polymerization of heterocyclic monomers

In the first part of this review the meaning of activation is discussed and selected examples of polymerizaton processes in which activation of monomer is required prior to actual propagation are presented. In some systems, activation of monomer proceeds with such a strong interaction between an activator and monomer that a new chemical entity is derived from the monomer. To describe the mechanism of such a process, the term ‘Activated Monomer Mechanism’ has been coined.

The main part of the review is concerned with cationic Activated Monomer (AM) polymerization of cyclic ethers. In this process, cyclic ether is activated by formation of protonated species in the presence of a protic acid. Reaction of the protonated (activated) cyclic ether with hydroxyl group containing compounds leads to ring opening reforming the hydroxyl group. Several repetitions of such a reaction constitute a chain process. Thus, in AM polymerization of cyclic ethers hydroxyl group containing compounds act as initiator, protic acid is a catalyst, growing chain end is fitted with hydroxyl group and the charged species is a protonated monomer. The important feature of such a polymerization mechanism is that due to the absence of charged species at the growing chain end, back-biting leading to the formation of macrocyclics can be eliminated.

The mechanism and kinetics of AM polymerization of cyclic ethers is discussed and the approach allowing one to determine the rate constant for propagation involving activated monomer species is outlined. The application of the AM concept to the copolymerization of cyclic ethers as well as to the polymerization of monomers containing both initiating (hydroxyl groups) and propagating (cyclic ether) functions within one molecule are presented.

In the subsequent parts of the review, examples of cationic AM polymerization of other types of heterocyclic monomers, including cyclic acetals, cyclic esters (lactones), amines and amides (lactams), are given.

Finally, the polyaddition of oxiranes to derivatives of phosphoric acid is discussed. Although this system does not conform to the AM polymerization scheme, it bears formal resemblance to earlier systems in such a sense that the activation of the cyclic ether is required for the reaction to occur.