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1.
This paper focuses on two recent topics in living cationic polymerization of vinyl monomers, i.e., (a) Development of new initiating systems: RCOOH/Lewis acid for vinyl ethers; CH3CH(C6H5)Cl/SnCl4/nBu4NCl for styrene. (b) Synthesis of shape-controlled poly(vinyl ethers): Tri-armed star polymers; Multi-armed spherical polymers. For the RCOOH-based systems, a generalized concept of living cationic polymerization was discussed on the basis of the effects of the counteranions (or R) and Lewis acids (ZnCl2 and EtAlCl2). The CH3CH(C6H5)Cl-based system permitted a truly living cationic polymerization of styrene. The tri- and multi-armed poly(vinyl ethers) included new amphiphilic polymers of unique topology, solubility, etc., all of which were prepared by living cationic polymerization. 相似文献
2.
Sadahito Aoshima Hideshi Onishi Masamichi Kamiya Kenji Shachi Eiichi Kobayashi 《Journal of polymer science. Part A, Polymer chemistry》1994,32(5):879-887
In the living cationic polymerization of isobutyl vinyl ether (IBVE) by the CH3CH (OiBu) OCOCH3 ( 1 )/EtAlCl2 initiating system in the presence of the added base in hexane at +40°C, the stability of the initiating system 1 /EtAlCl2, which form initiating species CH3CH⊕ (OiBu) derived from 1 , was investigated. In the presence of the Lewis base such as ethyl acetate or 1,4-dioxane, the active species was stable for 300 min even at +40°C in the absence of IBVE, and the living polymers were quantitatively obtained by adding IBVE. However, the active species was partly consumed by side reactions during the standing time for 60 min in the presence of a less basic additive such as ethyl benzoate, and about 50% of the active species was deactivated in the presence of methyl chloroacetate. Consequently, in the case of a less basic additive such as methyl chloroacetate (which was effective for the fast living polymerization), it can be seen that the careful selection of polymerization conditions was required. The living polymerization rate was dependent on the second order of EtAlCl2 concentration. EtAlCl2 induced the cleavage of 1 into CH3CH⊕ (OiBu) and EtAl?Cl2(OCOCH3), and the reactivity of CH3CH⊕ (OiBu) and propagating carbocation may be controlled by EtAl?Cl2(OCOCH3) with the aid of other EtAlCl2. Et1.5AlCl1.5 exists as a bimetallic complex of EtAlCl2 and Et2AlCl, and it is expected that the polymers having a bimodal molecular weight distribution will be obtained due to two kinds of counteranions coming from EtAlCl2 and Et2AlCl. However, in the cationic polymerization of IBVE by 1 /Et1.5AlCl1.5 in the presence of ethyl acetate, the living polymer exhibiting a unimodal and very narrow molecular weight distribution was obtained. Thereby, it was suggested that the counteranions, EtAl?Cl2(OCOCH3) and Et2Al?Cl(OCOCH3), exchange rapidly with each other. © 1994 John Wiley & Sons, Inc. 相似文献
3.
Motomasa Yonezumi Nanako Takano Shokyoku Kanaoka Sadahito Aoshima 《Journal of polymer science. Part A, Polymer chemistry》2008,46(20):6746-6753
A quite small dose of a poisonous species was found to induce living cationic polymerization of isobutyl vinyl ether (IBVE) in toluene at 0 °C. In the presence of a small amount of N,N‐dimethylacetamide, living cationic polymerization of IBVE was achieved using SnCl4, producing a low polydispersity polymer (weight–average molecular weight/number–average molecular weight (Mw/Mn) ≤ 1.1), whereas the polymerization was terminated at its higher concentration. In addition, amine derivatives (common terminators) as stronger bases allow living polymerization when a catalytic quantity was used. On the other hand, EtAlCl2 produced polymers with comparatively broad MWDs (Mw/Mn ~ 2), although the polymerization was slightly retarded. The systems with a strong base required much less quantity of bases than weak base systems such as ethers or esters for living polymerization. The strong base system exhibited Lewis acid preference: living polymerization proceeded only with SnCl4, TiCl4, or ZnCl2, whereas a range of Lewis acids are effective for achieving living polymerization in the conventional weak base system such as an ester and an ether. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6746–6753, 2008 相似文献
4.
Won Ok Choi Mitsuo Sawamoto Toshinobu Higashimura 《Journal of polymer science. Part A, Polymer chemistry》1990,28(11):2937-2948
The concentration ([P*]) and lifetime (half-life) of the propagating species were measured in the living cationic polymerization of isobutyl vinyl either initiated by the 1-(isobutoxy) ethyl acetate [CH3COOCH (OiBu) CH3]/ethylaluminum dichloride (EtAlCl2) system in the presence of excess 1,4-dioxane in n-hexane at 0 to +70°C; the acetate serves as a cationogen that forms an initiating vinyl ether-type carbocation. The measurements were based on the end-capping reaction with sodiomalonic ester [Na⊕?CH (COOEt)2], which was shown to react rapidly and quantitatively with the living growing end. From the terminal malonate group of the quenched polymers, [P*] was determined by 1H-NMR spectroscopy. In contrast to its constancy during the polymerization, [P*] progressively decreased with time after the complete consumption of monomer. The postpolymerization decay was first order in [P*], and the lifetime (half-life) of the living end was determined from the decay rate constant. The lifetime increased on lowering polymerization temperature, decreasing EtAlCl2 concentration, and increasing dioxane concentration. In particular, the “base-stabilized” living ends, generated by the CH3COOCH (OiBu) CH3/EtAlCl2/dioxane system, turned out extremely stable at 0°C (half-life > 5 days in the absence of monomer). 相似文献
5.
This paper focuses on in-situ 1H NMR analysis of model reactions that are directed to clarify the nature of the growing species in the following three classes of living cationic polymerization based on the stabilization of the growing carbocations with nucleophilic counteranions and added salts: (a) Vinyl ethers/HCl/SnCl4/added nBu4N+Y-; (b) Vinyl ethers/HX/ZnCl2 (salt free); (c) Styrene/HX/SnCl4/added nBu4N+Y- (X and Y: halogen) Through the NMR analysis, system (a) provides evidence for the generation of carbocations from adducts [CH3CH(OR)Cl] of vinyl ethers and hydrogen chloride and also for the suppression of such ionic species by the added salts. For systems (b) and (c) the spectroscopic observation demonstrated rapid counteranion exchanges in the growing species, indicating that upon reacting with a monomer the living end assumes an ionic character. 相似文献
6.
《高分子科学杂志,A辑:纯化学与应用化学》2013,50(6):529-548
The effect of 1,4-dioxane as an added base on the cationic polymerization of isobutyl vinyl ether (IBVE) initiated by carboxyl groups on carbon black surface/ethylaluminum dichloride (EtAlCl2) system was investigated. Although the cationic polymerization of IBVE by carbon black/EtAlCl2 system the absence of 1,4-dioxane instaneously proceeded and the monomer conversion achieved 100% within a minute. The molecular weight distribution (MWD) of polyIBVE obtained was very broad. On the contrary, the MWD of polyIBVE obtained was very narrow and narrower than that obtained from the carbon black/ZnCl2 initiating system by the addition of 1,4-dioxane. The number-average molecular weight (Mn) of polyIBVE obtained was directly proportional to monomer conversion in the cationic polymerization. However, the Mn of polyIBVE obtained from the polymerization by the initiating system in the the presence of 1,4-dioxane was smaller than that of the calculated value, assuming that polyl(IBVE) chain forms per unit carboxyl group on carbon black surface. It was concluded that carbon black/EtAlCl2 initiating systems in the presence of 1,4-dioxane has an ability to initiate “living-like” cationic polymerization of IBVE based on the above results. PolyIBVE was grafted onto a carbon black surface after quenching the above “living-like” cationic polymerization systems with methanol. 相似文献
7.
Masami Kamigaito Mitsuo Sawamoto Toshinobu Higashimura 《Journal of polymer science. Part A, Polymer chemistry》1993,31(12):2987-2994
Phosphoric and phosphinic acid derivatives (R1R2PO2H; R1, R2 = OPh, OPh; OnBu, OnBu; Ph, Ph; Ph, H) in conjunction with zinc chloride (ZnCl2) led to living cationic polymerization of isobutyl vinyl ether (IBVE) in toluene below 0°C. The number-average molecular weights (M?n) of the polymers (M?n > 2 × 104) were directly proportional to monomer conversion and in excellent agreement with the calculated values assuming that one polymer chain forms per R1R2PO2H molecule. Throughout the reaction, the molecular weight distributions (MWDs) stayed narrow (M?w/M?n ? 1.1). A dibasic acid, PhOP (O) (OH)2, coupled with ZnCl2, also induced living cationic polymerization of IBVE where one molecule of the acid generated two living polymer chains. The polymerization by (PhO)2PO2H/ZnCl2 and its model reactions were directly analyzed by 31P and 1H-NMR spectroscopy. The analysis showed that the acid initially forms the adduct [CH3CH(OiBu)OP(O)(OPh)2], the phosphate linkage of which is in turn activated by ZnCl2 so as to initiate living propagation. The finding thus indicates that (PhO)2PO2H indeed acts as an initiator in the living polymerization. The NMR analysis also suggested that an exchange reaction occurs between the phosphate group at the polymer terminal and the chlorine in ZnCl2. The occurrence of living IBVE polymerization with these various R1R2PO2H/ZnCl2 systems shows that phosphoric and phosphinic acids are another general class of protonic acids which are effective initiators for the living cationic polymerization assisted by Lewis acids. © 1993 John Wiley & Sons, Inc. 相似文献
8.
This paper discusses recent developments in living cationic polymerization of vinyl monomers, specifically focusing on (a) new initiating systems, (b) kinetics and mechanism, and (c) controlled polymer synthesis. The new initiating systems were based on nucleophilic stabilization of the growing carbocations, either by counteranions (as in phosphate/ZnI2 and Me3SiI/ZnI2 systems) or by added Lewis bases (as 2,6-dimethylpyridine for EtAlCl2). The kinetic study included the determination of the lifetime of living cationic polymers. The controlled polymer synthesis by living cationic processes led to not only end- and pendant-functionalized polymers of narrow molecular weight distributions but also star-shaped polymers and sequence-regulated vinyl ether oligomers with functional groups. 相似文献
9.
Yoshiaki Terada Shokyoku Kanaoka Toshinobu Higashimura 《Journal of polymer science. Part A, Polymer chemistry》2000,38(1):229-236
Cationic polymerization of n‐butyl propenyl ether (BuPE; CH3CH CHOBu, cis/trans = 64/36) was examined with the HCl–IBVE (isobutyl vinyl ether) adduct/ZnCl2 initiating system at −15 ∼ −78 °C in nonpolar (hexane, toluene) and polar (dichloromethane) solvents, specifically focusing on the feasibility of its living polymerization. In contrast to alkyl vinyl ethers, the living nature of the growing species in the BuPE polymerization was sensitive to polymerization temperature and solvent. For example, living cationic polymerization of IBVE can be achieved even at 0 °C with HCl–IBVE/ZnCl2, whereas for BuPE whose β‐methyl group may cause steric hindrance ideal living polymerization occurred only at −78 °C. Another interesting feature of this polymerization is that the polymerization rate in hexane is as large as in dichloromethane, much larger than in toluene. A new method in determining the ratio of the living growing ends to the deactivated ones was developed with a devised monomer‐addition experiments, in which IBVE that can be polymerized in a living fashion below 0 °C was added to the almost completely polymerized solution of BuPE. The amount of the deactivated chain ends became small in hexane even at −40 °C in contrast to other solvents. Thus hexane turned out an excellent solvent for living cationic polymerization of BuPE. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 229–236, 2000 相似文献
10.
Shokyoku Kanaoka Toshinobu Higashimura 《Journal of polymer science. Part A, Polymer chemistry》1999,37(19):3694-3701
In contrast to the common view, living cationic polymerization of p-methoxy- and p-t-butoxystyrenes proceeded in polar solvents such as EtNO2/CH2Cl2 mixtures, and involvement of free ionic growing species therein was examined. For example, the two alkoxystyrenes were polymerized with the isobutyl vinyl ether-HCl adduct/ZnCl2 initiating system at −15°C in such polar solvents as CH2Cl2 or EtNO2/CH2Cl2 [1/1 (v/v)], as well as toluene. The number average molecular weight (M̄n) of the polymers increased in direct proportion to the monomer conversion, even after sequential monomer addition, and the molecular weight distribution (MWD) stayed very narrow throughout the reaction. In addition, the M̄n agreed with the calculated values, assuming that one adduct molecule generates one living polymer chain. In these polar media the addition of a common ion salt retarded the polymerization, indicating that dissociated ionic species are involved in the propagating reaction. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3694–3701, 1999 相似文献
11.
Kotaro Satoh Yuya Mori Masami Kamigaito 《Journal of polymer science. Part A, Polymer chemistry》2019,57(3):465-473
In this work, we examined the synthesis of novel block (co)polymers by mechanistic transformation through anionic, cationic, and radical living polymerizations using terminal carbon–halogen bond as the dormant species. First, the direct halogenation of growing species in the living anionic polymerization of styrene was examined with CCl4 to form a carbon–halogen terminal, which can be employed as the dormant species for either living cationic or radical polymerization. The mechanistic transformation was then performed from living anionic polymerization into living cationic or radical polymerization using the obtained polymers as the macroinitiator with the SnCl4/n‐Bu4NCl or RuCp*Cl(PPh3)/Et3N initiating system, respectively. Finally, the combination of all the polymerizations allowed the synthesis block copolymers including unprecedented gradient block copolymers composed of styrene and p‐methylstyrene. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 465–473 相似文献
12.
Sachio Yoshikawa Rie Nishizaka Ken'ichi Oyanagi Norio Tsubokawa 《Journal of polymer science. Part A, Polymer chemistry》1995,33(13):2251-2256
The effect of zinc chloride (ZnCl2) on the cationic polymerization of isobutyl vinyl ether (IBVE) initiated by carboxyl groups on a carbon black surface was investigated. Although the polymerization of IBVE was initiated by carboxyl groups on the surface, the rate of polymerization was small and the molecular weight distribution (MWD) of poly IBVE was very broad. The rate of the polymerization was found to be drastically increased, and 100% monomer conversion was achieved in a short time by the addition of ZnCl2. The number-average molecular weights (Mn) of the polyIBVE were directly proportional to monomer conversion in the polymerization initiated by the carbon black/ZnCl2 system. By addition of the monomer at the end of the first-stage polymerization, the added monomer was smoothly polymerized at the same rate as in the first stage. The Mn of the polymer was in excellent agreement with the calculated value, assuming the polyIBVE chain forms per unit carboxyl group on the surface and MWD was narrow (Mw/Mn = 1.2 ~ 1.3). Based on the results, it is concluded that carbon black/ZnCl2 system has an ability to initiate the living cationic polymerization of IBVE. Furthermore, it was found that polyIBVE was grafted onto the carbon black surface after the quenching of the living polymer with methanol. © 1995 John Wiley & Sons, Inc. 相似文献
13.
Tomohide Yoshida Ken‐Ichi Seno Shokyoku Kanaoka Sadahito Aoshima 《Journal of polymer science. Part A, Polymer chemistry》2005,43(6):1155-1165
The living cationic polymerization of octadecyl vinyl ether (ODVE) was achieved with an 1‐(isobutoxy)ethyl acetate [CH3CH(OiBu)OCOCH3]/EtAlCl2 initiating system in hexane in the presence of an added weak Lewis base at 30 °C. In contrast to conventional polymers, poly(octadecyl vinyl ether) underwent upper‐critical‐solution‐temperature‐type phase separation in various solvents, such as hexane, toluene, CH2Cl2, and tetrahydrofuran, because of the crystallization of octadecyl chains. Amphiphilic block and random copolymers with crystallizable substituents of ODVE and 2‐methoxyethyl vinyl ether (MOVE) were synthesized via living cationic polymerization under similar conditions. Aqueous solutions of the copolymers yielded physical gels upon cooling because of strong interactions between ODVE units, regardless of the copolymer structure. The product gels, however, exhibited different viscoelastic properties: A 20 wt % solution of a block copolymer (400/20 MOVE/ODVE) became a soft physical gel that behaved like a typical gel, whereas the corresponding random copolymer gave a transparent but stiff gel with a certain relaxation time. Differential scanning calorimetry analysis confirmed that the crystalline–amorphous transition of the octadecyl chains was a key step for inducing such physical gelation. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1155–1165, 2005 相似文献
14.
Izabela Magdalena Zaleska Masaru Kitagawa Shinji Sugihara Isao Ikeda 《Journal of polymer science. Part A, Polymer chemistry》2009,47(19):5169-5179
Applications of metal‐free living cationic polymerization of vinyl ethers using HCl · Et2O are reported. Product of poly(vinyl ether)s possessing functional end groups such as hydroxyethyl groups with predicted molecular weights was used as a macroinitiator in activated monomer cationic polymerization of ε‐caprolactone (CL) with HCl · Et2O as a ring‐opening polymerization. This combination method is a metal‐free polymerization using HCl · Et2O. The formation of poly(isobutyl vinyl ether)‐b‐poly(ε‐caprolactone) (PIBVE‐b‐PCL) and poly(tert‐butyl vinyl ether)‐b‐poly(ε‐caprolactone) (PTBVE‐b‐PCL) from two vinyl ethers and CL was successful. Therefore, we synthesized novel amphiphilic, biocompatible, and biodegradable block copolymers comprised polyvinyl alcohol and PCL, namely PVA‐b‐PCL by transformation of acid hydrolysis of tert‐butoxy moiety of PTBVE in PTBVE‐b‐PCL. The synthesized copolymers showed well‐defined structure and narrow molecular weight distribution. The structure of resulting block copolymers was confirmed by 1H NMR, size exclusion chromatography, and differential scanning calorimetry. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5169–5179, 2009 相似文献
15.
Kenji Yamada Masahiko Minoda Takeaki Miyamoto 《Journal of polymer science. Part A, Polymer chemistry》1997,35(4):751-757
D -glucosamine-containing glycopolymers with well-controlled structure were synthesized by living cationic polymerization. To this end, D -glucosamine-containing vinyl ether (VE) of the type [CH2()CH(OCH2CH2OR)] was prepared, where R denotes a 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimide-β-D -glucopyranoside, i.e., the hydroxyl and amino groups in D -glucosamine residues are protected by acetyl and phthaloyl groups, respectively. It was found that (1) the efficient living cationic polymerization of VE monomer is achieved by a combination of ethylaluminum dichloride (EtAlCl2) with an adduct of trifluoroacetic acid (TFA) and isobutyl VE (IBVE) [CH3CH(OiBu)OCOCF3] (i.e., TFA/EtAlCl2 initiating system); and (2) the polymerization in toluene at the elevated temperature (0°C) is most suitable to proceed the homogeneous polymerization over the whole conversion range. The molecular weight distribution of the resulting polymers was very narrow ($ {\bar M}_w/{\bar M}_n \sim 1.1 $). Quantitative deprotection of the resulting precursor polymers was successfully achieved with hydrazine monohydrate to afford the corresponding water-soluble polymers with pendant D -glucosamine residues. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 751–757, 1997 相似文献
16.
Yu Shinke Arihiro Kanazawa Shokyoku Kanaoka Sadahito Aoshima 《Journal of polymer science. Part A, Polymer chemistry》2012,50(24):5041-5048
Living cationic polymerization of a vinyl ether with a naphthyl group [2‐(2‐naphthoxy)ethyl vinyl ether, βNpOVE] was achieved using base‐assisting initiating systems with a Lewis acid. The Et1.5AlCl1.5/1,4‐dioxane or ethyl acetate system induced the living cationic polymerization of βNpOVE in toluene at 0 °C. The living nature of this reaction was confirmed by a monomer addition experiment, followed by 1H NMR and matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry (MALDI‐TOF‐MS) analyses. In contrast, the polymerization of αNpOVE was not fully controlled; under similar conditions, it produced polymers with broad molecular weight distributions. The 1H NMR and MALDI‐TOF‐MS spectra of the resultant poly(αNpOVE) revealed that the products had undesirable structures derived from Friedel–Crafts alkylation. The higher reactivity of αNpOVE in electrophilic substitution reactions, such as the Friedel–Crafts reaction, was attributable to the greater electron density of the naphthyl ring, which was calculated based on frontier orbital theory. The naphthyl groups significantly affected the properties of the resultant polymer. For example, the glass transition temperatures (Tg) of poly(NpOVE)s are higher by approximately 40 °C than that of poly(2‐phenoxyethyl vinyl ether). © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
17.
Mitsuo Sawamoto 《Macromolecular Symposia》1994,85(1):33-43
The objective of this paper is to discuss: (i) the general approaches to living cationic polymerizations; (ii) the nature of the growing species thus generated. For the first, it is concluded that three general methods are currently available which involve the nucleophilic stabilization of the growing carbocations by (a) a suitable counteranion, (b) an added Lewis base, or (c) an added neutral salt. According to this view, a variety of initiating systems are classified. For the second, findings are presented for the recently developed living cationic polymerization of vinyl ethers by the HCl/SnCl4 initiating system in the presence of an added salt (nBu4N+Cl−). The nature of the growing species therein is discussed on the basis of the steric structure of the living polymers, relative to nonliving counterparts, and the in-situ 13C NMR spectroscopic analysis of model reactions where the interaction of the growing end model [CH3CH(OR)Cl] with SnCl4 and the added salt is analyzed. 相似文献
18.
Isotactic 6-armed star-shaped poly(vinyl alcohol) (PVA) with a narrow molecular weight distribution was successfully prepared by the living cationic polymerization of 6-armed star-shaped poly(tert-butyl vinyl ether) (PTBVE) and subsequent acidic ether cleavage. The PTBVE was synthesized using hexa(chloromethyl) melamine (HCMM) as a hexafunctional initiator and ZnI2 or ZnCl2 as an activator in toluene/MC (1/1 v/v) at −70 °C. A better living stability of PTBVE was obtained in the ZnCl2 activator system. The number average molecular weight and the polydispersity index of the 6-armed star-shaped PTBVE polymerized with ZnCl2 at −70 °C for 24 h were 156,000 g/mol and 1.47, respectively. The fraction of the mm sequence of the resulting PVA was 52%. 相似文献
19.
Sadahito Aoshima Takashi Fujisawa Eiichi Kobayashi 《Journal of polymer science. Part A, Polymer chemistry》1994,32(9):1719-1728
The living cationic polymerization of isobutyl vinyl ether (IBVE) was investigated in the presence of various cyclic and acyclic ethers with 1-(isobutoxy)ethyl acetate [CH3CH(OiBu)OCOCH3, 1 ]/EtAlCl2 initiating system in hexane at 0°C. In particular, the effect of the basicity and steric hindrance of the ethers on the living nature and the polymerization rate was studied. The polymerization in the presence of a wide variety of cyclic ethers [tetrahydrofuran (THF), tetrahydropyran (THP), oxepane, 1,4-dioxane] and cyclic formals (1,3-dioxolane, 1,3-dioxane) gave living polymers with a very narrow molecular weight distribution (MWD) (M?ω/M?n ≤ 1.1). On the other hand, propylene oxide and oxetane additives resulted in no polymerization, whereas 1,3,5-trioxane gave the nonliving polymer with a broader MWD. The polymerization rates were dependent on the number of oxygen and ring sizes, which were related to the basicity and the steric hindrance. The order of the apparent polymerization rates in the presence of cyclic ether and formal additives was as follows: nonadditive ~ 1,3,5-trioxane ? 1,3-dioxane > 1,3-dioxolane ? 1,4-dioxane ? THP > oxepane ? THF ? oxetane, propylene oxide ? 0. The polymerization in the presence of the cyclic formals was much faster than that of the cyclic ethers: for example, the apparent propagation rate constant k in the presence of 1,3-dioxolane was 103 times larger than that in the presence of THF. Another series of experiments showed that acyclic ethers with oxyethylene units were effective as additives for the living polymerization with 1 /EtAlCl2 initiating system in hexane at 0°C. The polymers obtained in the presence of ethylene glycol diethyl ether and diethylene glycol diethyle ether had very narrow molecular weight distribution (M?ω/M?n ≤ 1.1), and the M?n was directly proportional to the monomer conversion. The polymerization behavior was quite different in the polymerization rates and the MWD of the obtained polymers from that in the presence of diethyl ether. These results suggested the polydentate-type interaction or the alternate interaction of two or three ether oxygens in oxyethylene units with the propagating carbocation, to permit the living polymerization of IBVE. © 1994 John Wiley & Sons, Inc. 相似文献
20.
Yeong-Soon Gal Sam-Kwon Choi 《Journal of polymer science. Part A, Polymer chemistry》1993,31(2):345-350
The preparation and cyclopolymerization of dipropargyl sulfoxide were studied. The polymerization of dipropargyl sulfoxide was carried out by various transition metal catalysts. WCl6–EtAlCl2, MoCl5, and PdCl2 catalyst systems were very effective. The resulting poly(dipropargyl sulfoxide) structures were characterized by NMR (1H and 13C), IR, and elemental analysis to have conjugated polyene units. Poly(dipropargyl sulfoxide) prepared by PdCl2 was mostly soluble in organic solvents such as DMF and DMSO. Thermal and oxidative properties of poly(dipropargyl sulfoxide) were also studied. The electrical conductivity of iodine-doped poly(dipropargyl sulfoxide) was 5.2 × 10?2 Ω?1 cm?1. Comparisons of poly(dipropargyl sulfoxide) properties with other similar polymers from dipropargyl sulfur derivatives such as dipropargyl sulfide and dipropargyl sulfone were also carried out. © 1993 John Wiley & Sons, Inc. 相似文献