Synthesis of poly(cyclohexene oxide)‐block‐polystyrene by combination of radical‐promoted cationic polymerization,atom transfer radical polymerization and click chemistry

The combination of radical‐promoted cationic polymerization, atom transfer radical polymerization (ATRP) and click chemistry was employed for the efficient preparation of poly(cyclohexene oxide)‐block‐polystyrene (PCHO‐b‐PSt). Alkyne end‐functionalized poly(cyclohexene oxide) (PCHO‐alkyne) was prepared by radical‐promoted cationic polymerization of cyclohexene oxide monomer in the presence of 1,2‐diphenyl‐2‐(2‐propynyloxy)‐1‐ethanone (B‐alkyne) and an onium salt, namely 1‐ethoxy‐2‐methylpyridinium hexafluorophosphate, as the initiating system. The B‐alkyne compound was synthesized using benzoin photoinitiator and propargyl bromide. Well‐defined bromine‐terminated polystyrene (PSt‐Br) was prepared by ATRP using 2‐oxo‐1,2‐diphenylethyl‐2‐bromopropanoate as initiator. Subsequently, the bromine chain end of PSt‐Br was converted to an azide group to obtain PSt‐N₃ by a simple nucleophilic substitution reaction. Then the coupling reaction between the azide end group in PSt‐N₃ and PCHO‐alkyne was performed with Cu(I) catalysis in order to obtain the PCHO‐b‐PSt block copolymer. The structures of all polymers were determined. Copyright © 2010 Society of Chemical Industry     

Synthesis of well-defined bisbenzoin end-functionalized poly(ε-caprolactone) macrophotoinitiator by combination of ROP and click chemistry and its use in the synthesis of star copolymers by photoinduced free radical promoted cationic polymerization

A new well-defined bisbenzoin group end-functionalized poly(ε-caprolactone) macrophotoinitiator (PCL-(PI)₂) was synthesized by combination of ring opening polymerization (ROP) and click chemistry. The ROP of ε-CL monomer in bulk at 110 °C, by means of a hydroxyl functional initiator namely, 3-cyclohexene-1-methanol in conjunction with stannous-2-ethylhexanoate, (Sn(Oct)₂), yielded a well-defined PCL with a cyclohexene end-chain group (PCL-CH). The bromination and subsequent azidation of the cyclohexene end-chain group gave bisazido functionalized poly(ε-caprolactone) (PCL-(N₃)₂). Separately, an acetylene functionalized benzoin photoinitiator (PI-alkyne) was synthesized by using benzoin and propargyl bromide. Then the click reaction between PCL-(N₃)₂ and PI-alkyne was performed by Cu(I) catalysis. The spectroscopic studies revealed that poly(ε-caprolactone) with bisbenzoin photoactive functional group at the chain end (PCL-(PI)₂) with controlled chain length and low-polydispersity was obtained. This PCL-(PI)₂ macrophotoinitiator was used as a precursor in photoinduced free radical promoted cationic polymerization to synthesize an AB₂-type miktoarm star copolymer consisting of poly(ε-caprolactone) (PCL, as A block) and poly(cyclohexene oxide) (PCHO, as B block), namely PCL(PCHO)₂.     

One‐step,one‐pot photoinitiation of free radical and free radical promoted cationic polymerizations

We describe here a novel approach to photoinitiate free radical and cationic polymerizations concurrently, involving the use of benzoin in conjunction with an onium salt such as diphenyl iodonium or N‐alkoxy pyridinium salt. On photolysis, benzoyl radicals formed from the decomposition of benzoin initiate free radical polymerization of methyl methacrylate. The hydroxy benzyl radicals formed concomitantly are readily oxidized to the corresponding cation by the onium salt to initiate cationic polymerization of cyclohexene oxide in the same system. Evidence for two independent polymerizations was obtained from studies involving gel permeation chromatography, extractions, and infrared and proton nuclear magnetic resonance analysis of the polymers. The effect of the type of the onium salt on each polymerization was also investigated. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2389–2395, 2002     

Phthalic anhydride promoted ring‐opening polymerization of cyclohexene oxide catalyzed by dinuclear chromium complex supported by piperazine‐bridged [ONSO] ligand

New bimetallic chromium complexes bearing a piperazine‐bridged tetradentate‐dianionic iminethiobis(phenolate) (ONSO) ligand and an ancillary chloride group (complex 1 ) have been developed. Of interest, it was found that the complex 1 catalyzed copolymerization of cyclohexene oxide with phthalic anhydride (PA) gives a product with more than 97% ether linkage content, i.e. selective synthesis of poly(cyclohexene oxide), which is in sharp contrast to the mononuclear [ONSO]CrCl analogue where a resulting polymer with more than 86% ester units is achieved under identical conditions. The influences of PA loading, reaction time and temperature on the polymerization were investigated. According to the kinetics data, the apparent activation energy of the ring‐opening polymerization of cyclohexene oxide is 12.5 kJ mol^?1. A cationic polymerization mechanism is proposed according to the polymer structure and the interaction between metal complex 1 and PA. © 2019 Society of Chemical Industry     

Cationic polymerization using allyl sulfonium salt. 3. Allyl sulfonium salt/ascorbate redox couple

The cationic polymerization of cyclohexene oxide was initiated by reduction of allyl sulfonium salt in the presence of ascorbyl-6 hexadecanoate and copper (II) benzoate. A redox reaction in which the copper compound serving as an electron carrier for the initiation step was proposed.     

Synthesis of a graft polymer PVAc-g-[P(AN-r-BVE)-b-PCHO] in “one-step” by radical/cationic transformation polymerization and coupling reaction

This article reports a new “one-step” synthesis of graft polymers based on the radical/cationic transformation polymerization. Using the synthetic method proposed, a graft polymer (PVAc-g-[P(AN-r-BVE)-b-PCHO]) consisting of a partly hydrolyzed poly(vinyl acetate) (PVAc-OH) backbone and block polymer grafts of acrylonitrile/n-butyl vinyl ether random copolymer (P(AN-r-BVE)) and poly(cyclohexene oxide) (PCHO) was synthesized in situ by radical/cationic transformation polymerization of a mixture of AN/BVE/CHO in the presence of PVAc-OH. The graft polymer, PVAc-g-[P(AN-r-BVE)-b-PCHO], was fully characterized by ¹H NMR, IR, gel permeation chromatography and differential scanning calorimetry. The graft polymer, PVAc-g-[P(AN-r-BVE)-b-PCHO], was hydrolyzed with NaOH to form a poly(vinyl alcohol)-based amphiphilic graft polymer, PVA-g-[P(AN-r-BVE)-b-PCHO]. The aggregation behavior of the amphiphilic graft polymer was investigated briefly by atomic force microscopy and dynamic light scattering measurements.     

梳型紫外光快速固化聚氨酯的制备及涂层性能

以1,3-丙二醇、甲基丙烯酸缩水甘油酯为主要原料,无水四氯化锡为催化剂,三氟乙酸为助催化剂,合成了一种具有光化学活性的聚醚(PGMA)。此聚醚以碳氧键为主链,以甲基丙烯酸酯基为梳型侧链,端基为羟基。将上述具有光化学活性的聚醚(PMGA)与异佛尔酮二异氰酸酯(IPDI)反应,制得具有光化学活性的聚氨酯[Poly(PGMA-IPDI)]。采用FTIR和~1HNMR对PGMA和Poly(PGMA-IPDI)进行表征。在上述聚氨酯中加入活性稀释剂和光引发剂,制备出一种能够快速光固化的树脂,固化时间可以达到1 s,柔韧性达到0.5 mm、附着力为最高级级,同时固化涂层在盐溶液、水溶液、碱溶液中浸泡无脱落,在酸性水溶液中脱落时间也达到36 h,涂层具有优异的性能。     

Synthesis of PMMA‐PTHF‐PMMA and PMMA‐PTHF‐PST linear and star block copolymers

Combination of cationic, redox free radical, and thermal free radical polymerizations was performed to obtain linear and star polytetramethylene oxide (poly‐THF)‐polymethyl methacrylate (PMMA)/polystyrene (PSt) multiblock copolymers. Cationic polymerization of THF was initiated by the mixture of AgSbF₆ and bis(4,4′ bromo‐methyl benzoyl) peroxide (BBP) or bis (3,5,3′,5′ dibromomethyl benzoyl) peroxide (BDBP) at 20°C to obtain linear and star poly‐THF initiators with M_w varying from 7,500 to 59,000 Da. Poly‐THF samples with hydroxyl ends were used in the methyl methacrylate (MMA) polymerization in the presence of Ce(IV) salt at 40°C to obtain poly(THF‐b‐MMA) block copolymers containing the peroxide group in the middle. Poly(MMA‐b‐THF) linear and star block copolymers having the peroxide group in the chain were used in the polymerization of methyl methacrylate (MMA) and styrene (St) at 80°C to obtain PMMA‐b‐PTHF‐b‐PMMA and PMMA‐b‐PTHF‐b‐PSt linear and star multiblock copolymers. Polymers obtained were characterizated by GPC, FT‐IR, DSC, TGA, ¹H‐NMR, and ¹³C‐NMR techniques and the fractional precipitation method. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 219–226, 2004     

Synthesis and characterization of poly(4‐diphenylaminostyrene)‐Poly(9‐vinylanthracene) binary block copolymer

Block copolymerization of plural types of monomers offers a new opportunity for the preparation of a variety of multifunctional polymers. Poly(4‐diphenylaminostyrene) (PDAS)‐poly(9‐vinylanthracene) (PVAN) binary block copolymer (PDAS‐PVAN) was synthesized by (living) anionic polymerization using the benzyllithium/N,N,N′,N′‐tetramethylethylenediamine system. The photoluminescence emission of PDAS‐PVAN was enhanced by the fluorescence resonance energy transfer from PDAS block to PVAN block in PDAS‐PVAN. The hole drift mobility of the copolymer was controllable by the amount of triphenylamino groups in the polymer chain. The optical and electrical properties of PDAS‐PVAN were adjustable through the polymer chain structure. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Cyclohexene oxide mid‐chain functional macromonomer of poly(ε‐caprolactone): Synthesis,characterization, and photoinitiated cationic homo‐ and copolymerization

In this study, a novel well‐defined epoxy mid‐chain functional macromonomer of poly(ε‐caprolactone) (PCL) has been synthesized by ring‐opening polymerization (ROP) of ε‐caprolactone (ε‐CL) and epoxidation on workup with 3‐chloroperoxybenzoic acid. The ROP of ε‐CL monomer in bulk at 110°C, by means of a dihydroxy functional initiator namely, 3‐cyclohexene‐1,1‐dimethanol in conjunction with stannous‐2‐ethylhexanoate, (Sn(Oct)₂), yielded a well‐defined PCL with a cyclohexene mid‐chain group. The epoxidation of the cyclohexene (CH) mid‐chain group of PCL was performed using 3‐chloroperoxybenzoic acid. GPC, IR, and ¹H‐NMR analyses revealed that a low‐polydispersity macromonomer of PCL with the desired cyclohexene oxide (CHO) functionality at the mid‐chain was obtained. The photoinduced cationic polymerizations of this macromonomer yielded comb‐shaped and graft copolymers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis of well‐defined dendritic hyperbranched polymers by iterative methodologies using living/controlled polymerizations

This review presents firstly the synthesis of various dendritic hyperbranched polymers with well‐defined structures by generation‐based growth methodologies using living/controlled polymerization. Secondly, the synthesis of dendritic hyperbranched poly(methyl methacrylate)s (PMMAs) and their functionalized block copolymers using a novel iterative methodology is described. The methodology involves a two‐reaction sequence in each iterative process: (a) a linking reaction of α‐functionalized living anionic PMMA with tert‐butyldimethylsilyloxymethylphenyl (SMP) groups with benzyl bromide (BnBr)‐chain‐end‐functionalized polymer and (b) a transformation reaction of the SMP groups into BnBr functions. This reaction sequence is repeated several times to construct high‐generation (maximum seventh generation) dendritic hyperbranched polymers. Similar branched architectural block copolymers have also been synthesized by the same iterative methodology using other α‐functionalized living anionic polymers. Surface structures of the resulting dendritic hyperbranched block copolymers composed of PMMA and poly(2‐(perfluorobutyl)ethyl methacrylate) segments have been characterized using X‐ray photoelectron spectroscopy and contact angle measurements. Solution behaviors of dendritic hyperbranched PMMAs with different generations and branch densities are discussed based on their intrinsic viscosities, g′ values and R_h values. Copyright © 2007 Society of Chemical Industry     

Synthesis of an oxetane‐functionalized hemispiroorthocarbonate used as a low‐shrinkage additive in the cationic ultraviolet curing of oxetane monomers

The synthesis of an hemispiroorthocarbonate functionalized with an oxetane group is reported. The obtained monomer was used as a slow shrinkable additive in the cationic ultraviolet curing of a commercially available dioxetane resin. We evidenced polymer network flexibilization by increasing the oxetane‐functionalized hemispiroorthocarbonate content in the photocurable formulation. It was demonstrated that spiroorthocarbonate acted as a shrinkage reduction additive and reached expansion on volume after polymerization in the presence of 50 wt % of the functionalized spiroorthocarbonate. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

A glance at violet LED sensitive photoinitiators based on the spiroxanthene scaffold

A novel photoinitiator based on a spiroxanthene scaffold in the presence of an iodonium salt is proposed for the cationic ring‐opening polymerization of a diepoxide, as well as for the free‐radical polymerization of an acrylate upon violet LED exposure (385 and 405 nm). Good‐to‐excellent rates of polymerization and final conversions are obtained. These systems are characterized by a higher reactivity compared with that of anthracene/iodonium salt used as reference for cationic near UV polymerization. The addition of a poly(ionic liquid) improves the cationic polymerization profiles. The photochemical mechanisms are studied by steady‐state photolysis, fluorescence, and electron spin resonance spin‐trapping techniques. Molecular orbital calculations give an insight into the light absorption properties. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43213.     

Photocrosslinked polymer and interpenetrating polymer network for nonlinear optics

Two photocrosslinkable NLO polymers of poly(glycidyl methacrylate) substituted with 4‐nitro‐4′‐hydroxyl stilbene (PGMAS) and acryloyl‐functionalized epoxy‐based polymer (PENAA) carrying 4‐nitroaniline moieties were synthesized and characterized. By using the sulfonium salt cationic photoinitiator BDS · 2PF₆ which can induce cationic or/and radical polymerization, the photocrosslinking of PGMAS and the interpenetrating polymer network (IPN) formed by the photocrosslinking of PGMAS and PENAA simultaneously were reported. The poled and photocrosslinked polymer films and IPN films exhibit relatively stable second‐order nonlinear optical activity. The influence of stilbene isomerization in PGMAS films with different crosslink densities on the SHG stability was also investigated. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1081–1087, 1999     

Click‐ligation of coumarin to polyether polyols for polyurethane foams

A simple strategy for the synthesis and functionalization of polyurethanes is described. Anionic ring‐opening polymerization was combined with ‘click’ chemistry to synthesize polyols with fluorescent properties. This route allows the incorporation of a wide range of functionalities in the polyols with an easy, clean and highly selective process compatible with several types of functional groups. The proposed strategy opens the way to the production, in a cost‐effective way, of ‘smart’ polyurethanes with non‐conventional properties like fire retardancy, antimite properties, antibacterial properties, etc. Alkynyl groups were introduced into the polyol chains by the controlled addition of glycidyl propargyl ether as co‐monomer during a conventional anionic ring‐opening copolymerization with propylene oxide. Subsequently 4‐azidomethyl‐7‐methoxycoumarin molecules were introduced onto the alkynyl‐polyether polyols by copper‐catalysed cycloaddition reactions to produce end‐functionalized polyols. The chemical structure of the novel polyols was characterized using infrared spectroscopy, nuclear magnetic resonance spectroscopy, gel permeation chromatography with triple detection and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectroscopy. These characterization techniques confirmed the presence of a considerable amount of functional groups in the structure of the polyols. Finally, various fluorescent rigid foams, based on the functionalized polyols, were synthesized. Copyright © 2012 Society of Chemical Industry     

Structural and photooxidation studies of poly(styrene oxide) prepared with Maghnite‐H+ as cationic catalyst

The nature of irregularities and end‐groups in poly(styrene oxide) samples prepared using Maghnite‐H⁺ as a cationic catalyst were studied by ¹H‐ and ¹³C‐NMR at 200 MHz. Head‐to‐head (H‐H) and tail‐to‐tail (T‐T) irregularities are detected in all the samples studied. Secondary hydroxyl terminal groups are identified in polymers prepared with Maghnite‐H⁺. Poly(styrene oxide) was found to undergo chain scission by aging at 25°C. It was confirmed that oxidation of this type of polymers results from the important sensitivity of the polyether soft segment to oxidative degradation. For this reason, the scissions due to the oxidation of the material lead to notable quantities of low molecular weight photoproducts. Among the various structures produced by the oxidative degradation process, benzoate and secondary hydroxyl groups are identified by MALDI‐TOF‐MS. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of diblock,triblock, and multiblock copolymers containing poly(3‐hydroxy butyrate) units

A poly[(R,S)‐3‐hydroxybutyrate] macroinitiator (PHB‐MI) was obtained through the condensation reaction of poly[(R,S)‐3‐hydroxybutyrate] (PHB) oligomers containing dihydroxyl end functionalities with 4,4′‐azobis(4‐cyanopentanoyl chloride). The PHB‐MI obtained in this way had hydroxyl groups at two end of the polymer chain and an internal azo group. The synthesis of ABA‐type PHB‐b‐PMMA block copolymers [where A is poly(methyl methacrylate) (PMMA) and B is PHB] via PHB‐MI was accomplished in two steps. First, multiblock active copolymers with azo groups (PMMA‐PHB‐MI) were prepared through the redox free‐radical polymerization of methyl methacrylate (MMA) with a PHB‐MI/Ce(IV) redox system in aqueous nitric acid at 40°C. Second, PMMA‐PHB‐MI was used in the thermal polymerization of MMA at 60°C to obtain PHB‐b‐PMMA. When styrene (S) was used instead of MMA in the second step, ABCBA‐type PMMA‐b‐PHB‐b‐PS multiblock copolymers [where C is polystyrene (PS)] were obtained. In addition, the direct thermal polymerization of the monomers (MMA or S) via PHB‐MI provided AB‐type diblocks copolymers with MMA and BCB‐type triblock copolymers with S. The macroinitiators and block copolymers were characterized with ultraviolet–visible spectroscopy, nuclear magnetic resonance spectroscopy, gel permeation chromatography, cryoscopic measurements, and thermogravimetric analysis. The increases in the intrinsic viscosity and fractional precipitation confirmed that a block copolymer had been obtained. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1789–1796, 2004     

Low‐energy electron beam‐induced cationic polymerization with onium salts

Demand for higher polymer performance with very short cure times has resulted in the development of low energy electron beam processes. This article presents the results of such a process for curing two epoxy systems, namely 3,4‐epoxycyclohexylmethyl‐3′,4′‐epoxycyclohexane carboxylate and di‐glycidyl ether of bisphenol A (DGEBA), using the cationic photoinitiator salts, triarylsulfonium hexafluoroantimonate, and diaryliodonium hexafluoroantimonate, respectively. Glass transition temperature measurements were done using a modulated DSC method while the degree of conversion was measured using FTIR spectroscopy. Results indicate that for both epoxy systems a relatively low dosage of not more than 5 Mrad was sufficient to achieve up to 60% conversion, with up to 80% conversion achievable using 30 Mrad. The diaryliodonium salt appeared to be more effective than the sulphonium salt in the above study. The effect of varying photoinitiator concentration and the resulting glass transition temperature has been studied. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3099–3108, 2001     

Grafting polymer brushes on graphene oxide for controlling surface charge states and templated synthesis of metal nanoparticles

In this article, poly[(dimethylamino)ethyl methacrylate] (PDMAEMA) brushes were grafted onto graphene oxide (GO) sheet via noncovalent modification of pyrene terminated initiator and subsequent in situ surface‐initiated atom transfer radical polymerization (SI‐ATRP). The results of zeta‐potentials, dispersivity measurement as well as the permeability of cationic and anionic redox‐active probe molecules reveal that the as‐prepared GO/PDMAEMA composite exhibits zwitterionicity because of the presence of phenol hydroxyl, carboxyl, and amine groups and the charging state can be manipulated by controlling pH values. Furthermore, by ion exchange and in situ reduction, palladium and gold nanoparticles were successfully uploaded and the catalytic property of the uniformly distributed Pd‐Au nanoparticles on GO sheet was investigated. These results reported in this work may open primarily toward constructing a bridge among GO, charged polymer and metal nanoparticles and secondarily to represent a new strategy for uniformly depositing inorganic nanoparticles. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Visible light polymerization of epoxy monomers using an iodonium salt with camphorquinone/ethyl‐4‐dimethyl aminobenzoate

A visible light initiator system for the photoinduced cationic polymerization of epoxy monomers is reported. The system consists of camphorquinone (CQ) in combination with ethyl‐4‐dimethyl aminobenzoate (EDMAB) and a diaryliodonium salt (Ph₂ISbF₆.) The three‐component system efficiently photoinitiates the polymerization of monomers containing an epoxycyclohexane group, 3,4‐epoxycyclohexylmethyl 3',4'‐epoxycyclohexane carboxylate (UVR) and 1,3‐bis(3,4‐epoxycyclohexyl‐2‐ethyl),1,1,3,3‐tetramethyldisiloxane (SIB), under irradiation with blue light (λ = 467 nm). Very rapid photopolymerization resulted from irradiation of SIB containing Ph₂ISbF₆ in combination with CQ and better results were obtained in the presence of EDMAB. On the other hand, no polymerization was detected after irradiation of UVR photoactivated with Ph₂ISbF₆ and CQ. However, this monomer polymerized readily and to high conversion when EDMAB was present. Moreover, almost complete conversion of UVR occurs in the absence of external heating. The polymer resulting from UVR displayed higher values of compressive and flexural properties than the polymer prepared from SIB. This is explained in terms of a higher density of crosslinking points in UVR which is accompanied by a lower content of non‐reacted monomer; this has a plasticizing effect on the hardened material. © 2013 Society of Chemical Industry