Photo-induced Living Cationic Polymerization of Tetrahydrofuran. III. Synthesis of Poly(THF-co-3-MTHF)

Soukil Mah,Choi, Jia,Lee, Hansup,Choi, Soonja The Korean Fiber Society 2000 Fibers and polymers Vol.1 No.1

Poly(3-methyltetrahydrofuran)(3-MTHF) and poly(tetrahydrofuran-co-3-MTHF), having very narrow molecular weight distribution were successfully synthesized via photo-induced living cationic polymerization in the presence of diphenyliodonium hexafluorophosphate. Linear relationship between % conversion and number average molecular weight of resulting poly(3-MTHF) in the polymerization of 3-MTHF, carried out at -22$^{\circ}C$, indicates that the 5-membered cyclic oxonium ion, being responsible for the cationic propagation is stabilized by ion pall formation with hexafluorophosphate anion, supplied from the salt. The linear relationship between two parameters, mentioned above was also observed in the copolymerization of 3-MTHF with THF, carried out at 0 and -22$^{\circ}C$. The molecular structures including the copolymer composition and average molecular weight and its distribution is determined by reaction parameters such as monomer feed ratio and reaction temperature.

Living Cationic Polymerization of t-Butyl Vinyl Ether Initiated by iodine

Mah, Soukil,Jeon, Hyunjeong The Korean Fiber Society 2004 한국섬유공학회지 Vol.41 No.4

Living nature of the cationic polymerization of t-butyl vinyl ether(t-BVE), carried out at -78$^{\circ}C$ in a mixed solvent of toluene and diethyl ether using iodine as initiator has been investigated. The results showing attainment of 100% conversion and a linear dependence of the number average molar mass on % conversion strongly suggests the living nature of the polymerization in a limited range of iodine concentration. It is concluded that the living nature of the polymerization is ascribable to the stability of polarized C-I terminal of adduct, which is formed by the reaction of the monomer with iodine and activated by the pulling action of zinc iodide, which allows the insertion of monomer in both initiation and propagation in cationic nature. However, it is believed that this growing terminal is stable enough to depress the chain breaking process, such as chain transfer or termination. Non-living characteristics appearing at higher temperatures as well as higher iodine concentration was discussed in terms of the equilibrium established between polarized C-I terminal and dissociated carbocationic propagating species where chain breaking process operates. It was also found that highly isotactic poly(vinylalcohol) (PVA) containing more than 70% meso content is obtainable via hydrolysis of corresponding p(t-BVE).

Photo-induced Living Cationic Polymerization of Isobutyl Vinyl Ether in the Presence of Various Combinations of Halides of Diphenyliodonium and Zinc Salts in Methylene Chloride

Kwon Soonhon,Chun Hyunjeong,Mah Soukil The Korean Fiber Society 2004 Fibers and polymers Vol.5 No.4

Living nature of photoinduced cationic polymerization of isobutyl vinyl ether (IBVE) in the presence of various combinations of diphenyliodonium halide (DPIX), a photocationic initiator and zinc halide $(ZnX_2)$ in methylene chloride has been investigated. Attainment of $100\%$ conversion and a linear relationship between $\%$conversion and number average molar mass of the resulting polymer, strongly suggests the living nature of this system. Livingness of the polymerization system was observed irrespective to the type of halide anion of the initiator and zinc salts unless the reaction temperature is not higher than $-30^{\circ}C$. The rate of polymerization decreases in the order of iodide > bromide > chloride when halide salt of DPIX and $ZnX_2$ are used. It is postulated that the cationic initiation is started by the insertion of weakly basic monomer in to the activated C-X terminal of the monomer adduct which is a reaction product of monomer and HX, a photolytic product of DPIX, formed in situ during the photo-irradiation process. It was concluded that polymerization is initiated by the insertion of weakly basic monomer into activated C- X terminal of monomer adduct due to the pulling action of$ZnX_2$, which successively producing a new polarized C-X terminal for the propagation in cationic nature. This led us to a conclusion that the living nature of this cationic polymerization is ascribable to the polarized C-X growing terminal, which is stable enough to depress the processes of chain transfer or termination process.

PET Fabric Supported Fixed Site Carrier Membrane for Selective Metal ion Transport

Jin, Long Yi,Mah, Soukil The Korean Fiber Society 2002 Fibers and polymers Vol.3 No.1

Development of a novel fixed site carrier membrane (FCM), supported by PET fabric for metal ion separation is reported. The membranes were prepared by dipping PET fabric into the methylene chloride solution of Poly(5-vinyl-m-phe-nylene-m'-phenylene-32-crown-10) (P(VCE)), a polymeric metal ion carrier. It was found that the flux of mono-valent metal ion transported across the membrane is signif=cantly differed from each other and the flux decreases in the order $Cs^+$>$Rb^+$>$K^+$>$Na^+$>$Li^+$ irrespective to the anion except perchlorate anion. It was explained in terms of the stability of the complex, formed by crown ether unit of the P(VCE) and the various metal ions, meanwhile, the lower rate of transport in the presence of perchlorate anion was ascribed to its low hydrophilicity.

Copolymerization of 4′-vinylbenzo-15-crown-5 with Di(ethylene glycol) Ethyl Ether Acrylate

Jin, Long Yi,Mah, Soukil The Korean Fiber Society 2002 Fibers and polymers Vol.3 No.2

Radical copolymerization behavior of 4'-vinylbenzo-15-crown-5, a vinyl monomer having a pendant 15-membared crown ether unit (VCE) with di(ethylene glycol) ethyl ether acrylate (DEGEEA) was carried out in toluene solution using 2,2-azobisisobutyronitrile (AIBN) as an initiator. The copolymers were characterized by means of FT-IR, $^1{H-NMR}$, and $^{13}{C-NMR}$ . The reactivity ratio of VCE and DEGEEA, determined by Fineman-Ross and Kelen-Tudos method, gave values 0.55 for VCE, and 0.11 for DEGEEA respectively.

Living cationic polymerization of Viny Ethers in Presence of Iodomethyl Methyl Ether and Zinc Iodide

Kwon, Soonhong,Lee, Yunsung,Mah, Soukil The Korean Fiber Society 2001 Fibers and polymers Vol.2 No.1

Living cationic polymerization behaviors of isobutyl vinyl ehters (IBVE), initiated by iodomethyl methyl ether (IMME)/zinc iodide ($Znl_2$) have been investigated. The polymerization was carried out at 0, -15, and $-30^{\circ}C$ in toluene. It was found that the rate of polymerization increased as the IMME concentration increased and decreased as temperature decreased. 100% conversion was always achieved without exception. Furthermore, the number-average molecular weight ($M_{n}$) of polymers increased in direct proportion to monomer conversion. The molecular weights of polymers were in good agreement with the theoretical values, calculated on the basis that one polymer chain was formed by one IMME molecule and the values of polydispersity index are always less than 1.2, revealing the living nature. The living nature was also confirmed by synthesis of poly(IBVE-b-TBVE) by subsequent monomer addition of t-butyl vinyl ether (TBVE).

Synthesis of N-4-vinylbenzyl-monoaza-m-phenylene-34-crown-11 and Its Copolymerization with Styrene

Jin, Long Yi,Hou, Ruibin,Chen, Tie,Fang, Minghai,Mah, Soukil,Yin, Bingzhu The Korean Fiber Society 2007 Fibers and polymers Vol.8 No.2

A functional monomer, containing a 34-membered monoazacrown ether unit (VACE) as a pendant group has been synthesized by using resorcinol, tetraethylene glycol, p-tolenesulfonyl chloride and 4-vinylbenzyl chloride as starting materials. The product structure was characterized by means of FT-IR, $^1H-NMR$, EA and MS. Free radical homopolymerized VACE or copolymerized VACE with styrene (ST) by the conventional radical initiator 2,2'-azobis (isobutyronitrile) (AIBN) in toluene solution to afford corresponding polymers. The reactivity ratio of VACE and ST, determined by Fineman-Ross method, gave values 0.6 for VACE, and 1.4 for ST, respectively.

Diphenyliodonium염 존재하에서 비닐 에테르의 광양이온 리빙 중합(I)

권순홍,이연성,전현정,마석일,Kwon, Soonhong,Lee, Youngsung,Jeon, Hyunjeong,Mah, Soukil 한국섬유공학회 2002 한국섬유공학회지 Vol.39 No.4

Photo-induced living cationic polymerization of isobutyl vinyl ether (IBVE) has been newly developed in the presence of diphenyliodonium iodide (DPII). Zinc iodide was used as an activator in the polymerization reaction. A linear relationship between % monomer conversion and the number average molecular weight of the resulting polymer reveals the living nature. The increase in both the polymer yield and its molecular weight until the original monomer was exhausted reveals that the propagating cationic species have the long lifetime due to the absence of termination or chain transfer process. It became also evident that a PIBVE-based block copolymer can be obtained by the subsequent monomer addition technique from this photo-induced system. The effects of various factors such as concentrations of DPII and zinc iodide, temperature, and duration of photo-irradiation were also discussed.