Factors affecting product distributions in ethylene/styrene copolymerization by (aryloxo)(cyclopentadienyl)titanium complexes-MAO catalyst systems

Nomura, Kotohiro,Zhang, Hao,Byun, Doo-Jin Wiley Subscription Services, Inc., A Wiley Company 2008 Journal of polymer science Part A, Polymer chemist Vol.46 No.12

<P>Ethylene/styrene copolymerizations using Cp′TiCl<SUB>2</SUB>(O-2,6-<SUP>i</SUP>Pr<SUB>2</SUB>C<SUB>6</SUB>H<SUB>3</SUB>) [Cp′ = Cp* (C<SUB>5</SUB>Me<SUB>5</SUB>, 1), 1,2,4-Me<SUB>3</SUB>C<SUB>5</SUB>H<SUB>2</SUB> (2), tert-BuC<SUB>5</SUB>H<SUB>4</SUB> (3)]-MAO catalyst systems were explored under various conditions. Complexes 2 and 3 exhibited both high catalytic activities (activity: 504–6810 kg-polymer/mol-Ti h) and efficient styrene incorporations at 25, 40°C (ethylene 6 atm), affording relatively high molecular weight poly (ethylene-co-styrene)s with unimodal molecular weight distributions as well as with uniform styrene distributions (M<SUB>w</SUB> = 6.12–13.6 × 10<SUP>4</SUP>, M<SUB>w</SUB>/M<SUB>n</SUB> = 1.50–1.71, styrene 31.7–51.9 mol %). By-productions of syndiotactic polystyrene (SPS) were observed, when the copolymerizations by 1–3-MAO catalyst systems were performed at 55, 70 °C (ethylene 6 atm, SPS 9.0–68.9 wt %); the ratios of the copolymer/SPS were affected by the polymerization temperature, the [styrene]/[ethylene] feed molar ratios in the reaction mixture, and by both the cyclopentadienyl fragment (Cp′) and anionic ancillary donor ligand (L) in Cp′TiCl<SUB>2</SUB>(L) (L = Cl, O-2,6-<SUP>i</SUP>Pr<SUB>2</SUB>C<SUB>6</SUB>H<SUB>3</SUB> or N=C<SUP>t</SUP>Bu<SUB>2</SUB>) employed. Co-presence of the catalytically-active species for both the copolymerization and the homopolymerization was thus suggested even in the presence of ethylene; the ratios were influenced by various factors (catalyst precursors, temperature, styrene/ethylene feed molar ratio, etc.). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4162–4174, 2008</P> <B>Graphic Abstract</B> <P>Ethylene/styrene copolymerizations using Cp′TiCl<SUB>2</SUB>(O-2,6-<SUP>i</SUP>Pr<SUB>2</SUB>C<SUB>6</SUB>H<SUB>3</SUB>) [Cp′ = Cp* (1), 1,2,4-Me<SUB>3</SUB>C<SUB>5</SUB>H<SUB>2</SUB> (2), tert-BuC<SUB>5</SUB>H<SUB>4</SUB> (3)]-MAO catalysts were explored under various conditions. Complexes 2–3 exhibited high catalytic activities and efficient styrene incorporations at 25–40 °C (ethylene 6 atm), affording poly(ethylene-co-styrene)s with uniform molecular weight and styrene distributions. Syndiotactic polystyrene (SPS) was by-produced when the copolymerizations by 1–3 were performed at 55, 70 °C; ratios of the copolymer/SPS were affected by the temperature, [styrene]/[ethylene] feed molar ratios, and by both Cp′ and anionic donor ligand. Co-existence of the active species for both the copolymerization and the homopolymerization was thus suggested under these conditions. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.] <img src='wiley_img/0887624X-2008-46-12-POLA22765-gra001.gif' alt='wiley_img/0887624X-2008-46-12-POLA22765-gra001'> </P>

Co(acac)2 Mediated Controlled Radical Copolymerization of Vinyl Acetate and Methyl Acrylate Initiated by Benzoyl Peroxide

Mohammad Ali Semsarzadeh,Parisa Alamdari 한국고분자학회 2015 Macromolecular Research Vol.23 No.2

Cobalt mediated radical copolymerization of vinyl acetate (VAc) and methyl acrylate (MA) was successfullyperformed in the presence of cobalt(II) acetylacetonate (Co(acac)2), dimethylformamide (DMF) and benzoylperoxide (BPO) as catalyst, cobalt coordinating agent and initiator, respectively, at 45 oC. The individual monomerconversion and comonomer composition of copolymers were determined by 1H NMR spectroscopy. Molecularweight (Mn) and its distribution (Mw/Mn) were analyzed by GPC technique. The time dependence of ln[M]0/[M], thevariation of molecular weight with respect to the conversion, and molecular weight distribution of copolymers werestudied to evaluate controlled characteristics of copolymerization. It was found that Co(acac)2 successfully mediatedthe radical copolymerization of VAc and MA. Moreover, copolymer molecular weight and copolymerization rateincreased with increasing initial MA ratio. The spectroscopy analysis revealed VAc content in the copolymerincreased with conversion regardless of VAc initial ratio, indicating a gradient sequence distribution of the copolymer.

Methacrylate Polymers Having Pendant Chalcone Moieties

Gamze Barim,Ozgul Altun,Mustafa Gokhun Yayla 한국고분자학회 2015 폴리머 Vol.39 No.1

A new methacrylate copolymer that includes chalcone as a side group, poly(4-methacryloyloxyphenyl-4"-methoxystyryl ketone-co-styrene) was synthesized by free radical copolymerization. FTIR and 1H NMR spectroscopic techniques were used to characterize the homopolymers and copolymers. The copolymerizations were carried out to high conversions. Copolymer compositions were established by 1H NMR spectra analysis. The monomer reactivity ratios for copolymer system were determined by the linearized Kelen Tudos, and Extended Kelen Tudos methods and a non-linear least squares method. The molecular weights and polydispersity index of copolymers were measured by using the gel permeation chromatography (GPC). The effect of copolymer compositions on their thermal behavior were studied by differential scanning calorimetry and thermogravimetric analysis methods. The optical properties of the resulting copolymer were also investigated.

Kinetic Investigations of RAFT Polymerization: Difunctional RAFT Agent Mediated Polymerization of Methyl Methacrylate and Styrene

Jianying Ma,Hui Xuan Zhang 한국고분자학회 2015 Macromolecular Research Vol.23 No.1

A difunctional reversible addition-fragmentation transfer (RAFT) agent, S,S′-bis (α,α′-dimethylacetic acid)trithiocarbonate (BDAT) is synthesized and used as chain transfer agent (CTA) to mediate homopolymerization ofmethyl methacrylate (MMA) and random copolymerization of methyl methacrylate-styrene (St) system, respectively. Kinetic factors of these two polymerizations, which influence polymerization process and characteristics ofpolymers, are investigated. Experimental results show that molecular weights of polymers increase linearly withmonomer conversions and these two polymerization kinetics behaviors exhibit “controlled/living” characteristics. Forthe homopolymerization of MMA, molecular weights increase gradually and are close to their theoretical values. Wherever, for the random copolymerization of MMA-St system, the presence of St has important influence on thekinetics of copolymerization. Addition of St to this system induces an induction period and this period increase withincreasing content of St in monomer composition.

Synthesis and characterization of indeno[1,2-b]fluorene-based white light-emitting copolymer

Jeong, Eunjae,Kim, Sun Hee,Jung, In Hwan,Xia, Yangjun,Lee, Kwanghee,Suh, Hongsuk,Shim, Hong-Ku,Woo, Han Young Wiley Subscription Services, Inc., A Wiley Company 2009 Journal of polymer science Part A, Polymer chemist Vol.47 No.14

<P>An indenofluorene-based copolymer containing blue-, green-, and red light-emitting moieties was synthesized by Suzuki polymerization and examined for application in white organic light-emitting diodes (WOLEDs). Tetraoctylindenofluorene (IF), 2,1,3-benzothiadiazole (BT), and 4,7-bis(2-thienyl)-2,1,3-benzothiadiazole (DBT) derivatives were used as the blue-, green-, and red-light emitting structures, respectively. The number-average molecular weight of the polymer was determined to be 25,900 g/mol with a polydispersity index of 2.02. The polymer was thermally stable (T<SUB>d</SUB> = ∼398 °C) and quite soluble in common organic solvents, forming an optical-quality film by spin casting. The EL characteristics were fine-tuned from the single copolymer through incomplete fluorescence energy transfer by adjusting the composition of the red/green/blue units in the copolymer. The EL device using the indenofluorene-based copolymer containing 0.01 mol % BT and 0.02 mol % DBT units (PIF-BT01-DBT02) showed a maximum brightness of 4088 cd/m<SUP>2</SUP> at 8 V and a maximum current efficiency of 0.36 cd/A with Commission Internationale de L'Eclairage (CIE) coordinates of (0.34, 0.32). The EL emission of PIF-BT01-DBT02 was stable with respect to changes in voltage. The color emitted was dependent on the thickness of the active polymer layer; layer (∼60 nm) too thin was unsuitable for realizing WOLED via energy transfer. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3467–3479, 2009</P> <B>Graphic Abstract</B> <P>We have synthesized an indenofluorene-based copolymer composed of blue-, green-, and red-emitting comonomers by Suzuki polymerization to produce white-light emission. By fine-tuning the composition of red/green/blue units and partial energy transfer among them, pure and stable white emission was obtained with the polymer containing 0.01 mol % 2,1,3-benzothiadiazole and 0.02 mol % 4,7-bis(2-thienyl)-2,1,3-benzothiadiazole. It showed bright white electroluminescence (4088 cd/m<SUP>2</SUP>) and a luminance efficiency of 0.36 cd/A with the CIE coordinates of (0.34, 0.32). The color emitted was dependent on the thickness of the active layer; a layer too thin was unsuitable for realizing white emission via energy transfer. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]</P> <img src='wiley_img/0887624X-2009-47-14-POLA23422-gra001.gif' alt='wiley_img/0887624X-2009-47-14-POLA23422-gra001'>

CO2/Propylene Oxide Copolymerization with a Bifunctional Catalytic System Composed of Multiple Ammonium Salts and a Salen Cobalt Complex Containing Sulfonate Anions

서영현,현용빈,이현주,이홍철,이정현,정선미,이분열 한국고분자학회 2021 Macromolecular Research Vol.29 No.12

A (Salen)Co(III) complex tethering four quaternary ammonium salts with covalent bonds is one of the most highly active catalysts for CO2/epoxide copolymerization. In this work, we aimed to prepare similar (Salen)Co(III) complexes to which quaternary ammonium salts are linked via ionic interactions. Thus, multiple ammonium salts containing 2-5 quaternary ammonium salt units and (Salen)Co(III) complexes containing one or two -SO3 -[PhNH3]+ moieties were prepared. A binary catalytic system composed of the prepared multiple ammonium salts and the prepared (Salen)Co(III) complex containing -SO3 -[(nBu)4N]+ moieties showed high activity (TOF, 1500-4500 h-1) for CO2/propylene oxide (PO) copolymerization, whereas a combination of the multiple ammonium salts and the conventional (Salen)Co(III) complex not containing -SO3 -[(nBu)4N]+ moieties was inactive under the identical polymerization conditions of [PO]/[Co] = 20000. However, a substantial amount of cyclic carbonate was concomitantly generated, especially when a (Salen)Co(III) complex containing two -SO3 -[(nBu)4N]+ moieties was used (25-30%). This side-reaction could be mitigated by ca. 50% by employing a (Salen)Co(III) complex containing one -SO3 -[(nBu)4N]+ moiety. Cyclic carbonate generation can reasonably be ascribed to ammonium salts ([(nBu)4N]+[carbonate]-) not linked to the (Salen)Co(III) complex formed in the binary catalytic system.

플라즈마 처리된 폴리프로필렌 표면 위에 글리시딜메타크릴레이트의 에멀젼 그래프팅

지한솔(Han Sol Ji),류옥연(Xu Yan Liu),최호석(Ho Suk Choi),김재하(Jae Ha Kim),박한오(Han Oh Park) 한국고분자학회 2012 폴리머 Vol.36 No.1

글리시딜메타크릴레이트(GMA)의 플라즈마 유도 그래프트 공중합을 통해 기재로 사용한 평판형 폴리프로필렌 위에 에폭시 그룹을 도입하였다. 그래프트 공중합은 에멀젼 공중합법을 적용하였고, 기존의 용액 공중합과 비교하여 그 효과를 확인하고자 하였다. 대기압 플라즈마 처리 조건은 RF power 200 W, 처리시간 30초, Ar 기체 유속 6 LPM으로 고정하였고, 처리 후의 대기 중 노출시간 역시 5분으로 고정하였다. 중합반응에서는 GMA의 농도, 반응온도, 반응시간에 따라 표면 그래프트도의 변화를 최적화하였다. 그 결과, GMA 농도 12%, 반응온도 90℃, 반응시간 5시간으로 중합하였을 때 가장 높은 그래프트도를 나타내었다. 분석 결과, 같은 반응조건 하에서 에멀젼 중합이 용액 중합에 비하여 더 많은 에폭시 그롭 도입에 효과적임을 확인하였다. Glycidyl methacrylate (GMA) was used to introduce epoxy groups on the surface of polypropylene (PP) plate, used as a substrate, through plasma-induced graft copolymerization. Emulsion polymerization was applied for graft copolymerization of GMA and was compared with conventional solution polymerization to confirm its effect. Plasma treatment conditions under one atmospheric pressure were fixed as follows; the RF power of 200 W, the treatment time of 30 sec, the Ar gas flow rate of 6 LPM, and the exposure time of treated PP samples in air of 5 min. For graft-copolymerization, GMA concentration, reaction temperature, and reaction time was optimized to maximize the grafting degree of GMA. The maximum grafting degree of GMA was obtained at the condition of 12%-GMA concentration, 90 oC reaction temperature, and 5 hr-reaction time. Analysis results supported that the emulsion polymerization was more effective than the solution polymerization for grafting more GMAs on the surface of PP plate under the same reaction conditions.

A Kinetic Monte Carlo Simulation of Individual Site Type of Ethylene and α-Olefins Polymerization

S. M. Ghafelebashi Zarand,S. Shahsavar,M. R. Jozaghkar 대한화학회 2018 대한화학회지 Vol.62 No.3

The aim of this work is to study Monte Carlo simulation of ethylene (co)polymerization over Ziegler-Natta catalyst as investigated by Chen et al. The results revealed that the Monte Carlo simulation was similar to sum square error (SSE) model to prediction of stage II and III of polymerization. In the case of activation stage (stage I) both model had slightly deviation from experimental results. The modeling results demonstrated that in homopolymerization, SSE was superior to predict polymerization rate in current stage while for copolymerization, Monte Carlo had preferable prediction. The Monte Carlo simulation approved the SSE results to determine role of each site in total polymerization rate and revealed that homopolymerization rate changed from site to site and order of center was different compared to copolymerization. The polymer yield was reduced by addition of hydrogen amount however there was no specific effect on uptake curve which was predicted by Monte Carlo simulation with good accuracy. In the case of copolymerization it was evolved that monomer chain length and monomer concentration influenced the rate of polymerization as rate of polymerization reduced from 1-hexene to 1-octene and increased when monomer concentration proliferate.

A Kinetic Monte Carlo Simulation of Individual Site Type of Ethylene and α-Olefins Polymerization

Zarand, S.M. Ghafelebashi,Shahsavar, S.,Jozaghkar, M.R. Korean Chemical Society 2018 대한화학회지 Vol.62 No.3

The aim of this work is to study Monte Carlo simulation of ethylene (co)polymerization over Ziegler-Natta catalyst as investigated by Chen et al. The results revealed that the Monte Carlo simulation was similar to sum square error (SSE) model to prediction of stage II and III of polymerization. In the case of activation stage (stage I) both model had slightly deviation from experimental results. The modeling results demonstrated that in homopolymerization, SSE was superior to predict polymerization rate in current stage while for copolymerization, Monte Carlo had preferable prediction. The Monte Carlo simulation approved the SSE results to determine role of each site in total polymerization rate and revealed that homopolymerization rate changed from site to site and order of center was different compared to copolymerization. The polymer yield was reduced by addition of hydrogen amount however there was no specific effect on uptake curve which was predicted by Monte Carlo simulation with good accuracy. In the case of copolymerization it was evolved that monomer chain length and monomer concentration influenced the rate of polymerization as rate of polymerization reduced from 1-hexene to 1-octene and increased when monomer concentration proliferate.

Preparation and Physical Properties of a Silicone Hydrogel Contact Lens Grafted with a Phosphorylcholine-Containing Hydrophilic Copolymer

배재호,최백서,김영진,이현미,김기홍,한윤수 한국고분자학회 2022 Macromolecular Research Vol.30 No.7

Silicone hydrogel contact lenses (SiH CLs) covalently grafted with a highwater- content copolymer layer, poly(2-methacryloyloxyethyl phosphorylcholineco- 2-hydroxyethyl acrylate) [P(MPC-co-HEA)], were fabricated, and their physical properties were investigated. SiH CLs were first prepared by radical copolymerization of a siloxane monomer and hydrophilic comonomers, and they were exposed to oxygen plasma to create peroxide groups on the lens surfaces. By letting peroxide- containing (O2-plasma-treated) SiH CLs act as a thermal free radical initiator, the P(MPC-co-HEA) layer with a water content of approximately 87% could be incorporated onto the surface by graft copolymerization between the lenses and mixed monomers (MPC and HEA). A P(MPC-co-HEA)-grafted SiH CL showed a contact angle of 49.9°, decreased from that of a pristine SiH CL (89.6°). The oxygen permeability of the P(MPC-co-HEA)-grafted SiH CL was recorded to be 54.46 barrer, almost the same as that of the pristine SiH CL (56.01 barrer). Meanwhile, the optical transmittance, tensile strength, and thermal characteristics of the P(MPC-co-HEA)-grafted SiH CL did not deteriorate following the O2 plasma treatment and graft copolymerization.