Vinyl‐addition copolymerization of norbornene and polar norbornene derivatives using novel bis(β‐ketoamino)Ni(II)/B(C6F5)3/AlEt3 catalytic systems

Copolymerization of norbornene (NBE) and polar norbornene derivatives undergoes vinyl polymerization by using novel catalyst systems formed in situ by combining bis(β‐ketoamino)Ni(II) complexes {Ni[R₁C(O)CHC(NR₃)R₂]₂ (R_l = R₂ = CH₃, R₃ = naphthyl, 1 ; R₁ = R₂ = CH₃, R₃ = C₆H₅, 2 ; R₁ = C₆H₅, R₂ = CH₃, R₃ = naphthyl, 3 ; R_l = R₂ = CH₃, R₃ = 2, 6‐(CH₃)₂C₆H₃, 4 ; R₁ = R₂ = CH₃, R₃ = 2, 6‐′Pr₂C₆H₃ 5 ; R₁ = C₆H₅, R₂ = CH₃, R₃ = 2, 6‐′Pr₂C₆H₃, 6 )} and B(C₆F₅)₃/AlEt₃ in toluene. The 1 /B(C₆F₅)₃/AlEt₃ catalytic system is effective for copolymerization of NBE with NBE OCOCH₃ and NBE CH₂OH, respectively, and copolymerization activity is followed in the order of NBE CH₂OH > NBE OCOCH₃ > NBE CN. The molecular weights of the obtained poly(NBE/NBE CH₂OH) reached 5.97 × 10⁴ to 2.07 × 10⁵ g/mol and the NBE CH₂OH incorporation ratios reached 7.0–55.4 mol % by adjusting the comonomer feedstock composition. The copolymerization of NBE and NBE CH₂OH also depend on catalyst structures and activity of catalyst followed in the order of 2 > 1 > 3 > 5 > 4 > 6 . The molecular weights and NBE CH₂OH incorporation ratios of poly(NBE/NBE CH₂OH) were adjustable to be 1.91–5.37 × 10⁵ g/mol and 9.5–41.1 mol %  OH units by using catalysts 1 – 6 . The achieved copolymers were confirmed to be vinyl‐addition type, noncrystalline and have good thermal stability (T_d = 380–410°C). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Binary copolymerization of 4‐methyl‐1,3‐pentadiene with styrene,butadiene and isoprene catalysed by a titanium [OSSO]‐type catalyst

Binary copolymerization of 4‐methyl‐1,3‐pentadiene (4MPD) with styrene, butadiene and isoprene promoted by the titanium complex dichloro{1,4‐dithiabutanediyl‐2,2′‐bis[4,6‐bis(2‐phenyl‐2‐propyl)phenoxy]}titanium activated by methylaluminoxane is reported. All the copolymers are obtained in a wide range of composition and the molecular weight distributions obtained from gel permeation chromatographic analysis of the copolymers are coherent with the materials being copolymeric in nature. The copolymer microstructure was fully elucidated by means of ¹H NMR and ¹³C NMR spectroscopy. Differential scanning calorimetry shows an increase of glass transition temperature (T_g) with the amount of 4MPD in the copolymers with butadiene and isoprene, while in the copolymers with styrene T_g is increased on increasing the amount of styrene. © 2016 Society of Chemical Industry     

Novel bis(benzoin) titanium catalyst for homo- and copolymerization of norbornene with ethylene: Synthesis, characterization and catalytic properties

A novel titanium(IV) dimeric complex [(OC(Ph)HC(Ph)O)TiCl(μ-OCH(Ph)C(Ph)(n-Bu)O)]₂ (1) was synthesized and characterized, and its catalytic behaviors toward homo- and copolymerization of ethylene (E) and norbornene (NB) were also investigated. X-ray diffraction analysis of single crystal structure revealed that the titanium complex features a binuclear and six-coordinate, pseudo-octahedral geometry around titanium metal center with oxo-bridge in the solid state. Activated with methylalumoxane (MAO), the titanium complex exhibited good activities for the homopolymerizations of ethylene and norbornene with long lifetime and produced high-molecular weight linear PE and vinyl-type PNB, respectively. E-NB copolymers with high-molecular weight and high NB incorporation content could be also obtained by this catalyst. The incorporation of NB in the E-NB copolymers could be controlled by varying monomer ratio and reaction temperature. ¹³C NMR analyses showed that the microstructures of the E-NB copolymers are predominantly alternated and isolated NB units, but the dyad and triad sequences of NB unit could be detected in the copolymers with high NB incorporation. The monomer reactivity ratios of the copolymerization were measured to be r_E = 6.0, r_N = 0.05 at 30 °C.     

Novel Ni and Pd(benzocyclohexan‐ketonaphthylimino)2 complexes for copolymerization of norbornene with octene

Two novel late transition metals complexes with bidentate O?N chelate ligand, Mt(benzocyclohexan‐ketonaphthylimino)₂ {Mt(bchkni)₂: bchkni ?C₁₀H₈(O)C[N(naphthyl)CH₃]; Mt ? Ni, Pd}, were synthesized. In the presence of B(C₆F₅)₃, both complexes exhibited high activity toward the homo‐polymerization of norbornene (NB) (as high as 2.7 × 10⁵ g_polymer/mol_Ni·h for Ni(bchkni)₂/B(C₆F₅)₃ and 2.3 × 10⁵ g_polymer/mol_Pd·h for Pd(bchkni)₂/B(C₆F₅)₃, respectively). Additionally, both catalytic systems showed high activity toward the copolymerization of NB with 1‐octene under various polymerization conditions and produced the addition‐type copolymer with relatively high molecular weights (0.1–1.4 × 10⁵g/mol) as well as narrow molecular weight distribution. The 1‐octene content in the copolymers can be controlled up to 8.9–14.0% for Ni(bchkni)₂/B(C₆F₅)₃ and 8.8–14.6% for Pd(bchkni)₂/B(C₆F₅)₃ catalytic system by varying comonomer feed ratios from 10 to 70 mol %. The reactivity ratios of two monomers were determined to be r_1‐octene = 0.052, r_NB = 8.45 for Ni(bchkni)/B(C₆F₅)₃ system, and r_1‐octene = 0.025, r_NB = 7.17 for Pd(bchkni)/B(C₆F₅)₃ system by the Kelen‐TÜdÕs method. The achieved NB/1‐octene copolymers were confirmed to be noncrystalline and exhibited good thermal stability (T_d > 400°C, T_g = 244.1–272.2°C) and showed good solubility in common organic solvents. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Highly trans‐1,4‐specific polymerization of 1,3‐butadiene catalyzed by [2,6‐bis{(4S)‐ (−)‐isopropyl‐2‐oxazolin‐2‐yl}pyridine] chromium complex activated with modified methylaluminoxane

Chromium complexes with N,N,N‐tridentate ligands, LCrCl₃ (L = 2,6‐bis{(4S)‐(?)‐isopropyl‐2‐oxazolin‐2‐yl}pyridine ( 1 ), 2,2′:6′,2″‐terpyridine ( 2 ), and 4,4′,4″‐tri‐tert‐butyl‐2,2′:6′,2″‐terpyridine ( 3 )), were prepared. The structures of 1 and 2 were determined by X‐ray crystallography. Upon activation with modified methylaluminoxane (MMAO), 1 catalyzed the polymerization of 1,3‐butadiene, while 2 and 3 was inactive. The obtained poly(1,3‐butadiene) obtained with 1 ‐MMAO was found to have completely trans‐1,4 structure. The 1 ‐MMAO system also showed catalytic activity for the polymerization of isoprene to give polyisoprene with trans‐1,4 (68%) and cis‐1,4 (32%) structure. Copyright © 2011 Society of Chemical Industry     

Comparison of thermal properties of ethylene‐norbornene copolymers prepared by batch and semi‐batch processes

Ethylene‐norbornene copolymers (ENCs) with various norbornene (NB) fractions could be synthesized by metallocene catalyst in both batch and semi‐batch processes. The batch process with long reaction time produced the ENC samples having considerable copolymer composition drift (CCD) while the semi‐batch process yielded narrow CCD. Furthermore, the effects of CCD on the resultant ENC's thermal properties were discussed. It was found that the thermal properties were dependent on both the NB fraction in obtained ENC and its CCD. The work demonstrated the importance of controlling CCD in the production of ENCs for superior materials properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Polymerization of norbornene using bis(β‐ketoamino)nickel(II)/MAO catalytic systems

The polymerizations of norbornene were investigated using a series of bis(β‐ketoamino)nickel(II) complexes( 1–6 ) in combination with methylaluminoxane (MAO) in toluene solution. The effects of catalyst structure, Al/Ni molar ratio, reaction temperature, and reaction time on catalytic activity and molecular weight of the polynorbornene were examined in detail. The electronic effect of the substituent around the imino group in the ligand is stronger than the steric bulk one on the polymerization activities, and the activities are in the order of 1 > 2 > 4 > 5 > 6 > 3 . The obtained polynorbornenes were characterized by means of ¹H‐NMR, ¹³C‐NMR, FTIR, TG, and WAXD techniques. The analyses results of polymers' structures and properties indicate that the polymerization reaction of norbornene runs in vinyl‐addition polymerization mode. The obtained polynorbornene was confirmed to be vinyl‐type and atactic polymers and showed good thermostability (T_dec > 458°C) and were noncrystalline but had short‐range order. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4172–4180, 2006     

Vinyl polymerization of norbornene with bis(imino)pyridyl nickel(II) complexes

A series of different steric hindrance nickel(II) complexes 1 – 6 bearing 2,6‐bis(imino)pyridine ligands have been synthesized and characterized. The molecular structures of the complexes 3 – 5 were determined by X‐ray diffraction analysis. The coordination geometry around the nickel center of the complexes is either square pyramid for complexes 3 and 4 or trigonal bipyramid for complex 5 . All of the nickel complexes exhibit high catalytic activity for norbornene polymerization in the presence of MAO, although low activity for ethylene oligomerization and polymerization. The effects of the Al/Ni ratio, halogen, monomer concentration, temperature, and reaction time on activity of catalyst for norbornene polymerization and polymer microstructure were investigated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Ring‐opening metathesis polymerization of norbornene catalyzed by tantalum and niobium complexes with chelating O‐donor ligands

BACKGROUND: In comparison with group 6 transition metals, such as tungsten and molybdenum, and group 8 metal ruthenium, group 5 metal‐based catalysts for ring‐opening metathesis polymerization (ROMP) have remained much less studied. The few reported ROMP catalysts of group 5 metals require multiple reaction steps to be synthesized, and are highly sensitive to air and moisture. RESULTS: A series of pentavalent tantalum and niobium complexes having catecholato, tropolonato, hinokitiolato, biphenolato and binaphtholato ligands were prepared and their catalytic activities for the ROMP of norbornene (NBE) were studied in the presence of trialkylaluminium as a co‐catalyst. Among these complexes, the tantalum complexes showed high activity upon activation with Buⁱ₃Al. In sharp contrast, the niobium complexes were effectively activated with Me₃Al. The polymers obtained with these complexes had high molecular weights (M_n > 10⁵ g mol⁻¹) and relatively narrow molecular weight distributions (M_w/M_n ≈ 2). CONCLUSION: We found that easily accessible and relatively stable tantalum and niobium complexes with such chelating O‐donor ligands showed high catalytic activity for ROMP of NBE depending on the kind of co‐catalyst. These findings could contribute to future development of ROMP catalysts. Copyright © 2008 Society of Chemical Industry     

Ring opening metathesis copolymerization of norbornene with norbornadiene from solutions with different mole fractions of the comonomers catalyzed by Ru‐amine complexes

Copolymers from norbornene (NBE) with norbornadiene (NBD) were synthesized via ring opening metathesis copolymerization varying the mole fractions of the comonomers (0.8 : 0.2; 0.6 : 0.4; 0.4 : 0.6; 0.2 : 0.8) for a total monomer quantity of 5000 equivalents/[Ru]. The batch reactions were performed with [RuCl₂(PPh₃)₂(amine)] complex types as precatalysts, where amine is perhydroazepine ( 1 ) or piperidine ( 2 ), in CHCl₃ (2 mL) in the presence of ethyl diazoacetate (5 μL) for different intervals of times (5, 30, 60, and 120 min) at 40°C. The copolymers were characterized by ¹³C NMR. Quantitative yields of isolated materials were obtained from solutions with NBD : NBE 0.8 : 0.2 mole fraction in the presence of 1, decreasing to 70% for NBD : NBE 0.2 : 0.8 solutions. Concerning 2 , the yields were 70% at most. Polymeric materials obtained with 1 were less soluble in CHCl₃ than those synthesized with 2 . The dependence of the reaction yields and occurrence of crosslinking on the starting NBE : NBD proportion related to reactivity of the complexes 1 and 2 were discussed. A few differences in the amines such as ancillary ligands were sufficient to change the reactivity of the {RuCl₂(PPh₃)} moiety complex to provide copolymers with different compositions. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Ring‐opening copolymerization of epoxycyclohexane and phthalic anhydride catalyzed by the asymmetric Salen‐CrCl complex

A new metallic chromium complex with asymmetric salen ligand and ancillary chloride group (complex 1 ) has been synthesized and applied as co‐catalytic system with bis(triphenylphosphine)iminium chloride (PPNCl) for the polymerization of epoxycyclohexane (CHO) and phthalic anhydride (PA). The catalyst loading, polymerization temperature, reaction time and type of co‐catalyst were varied in order to explore the influences on the catalytic activity of 1 . It was found that 1 exhibited relatively good activity in the catalytic copolymerization of PA and CHO to form the product with more than 90% ester linkage content under mild conditions after the addition of the PPNCl co‐catalyst. This was in sharp contrast to the dinuclear [ONSO]CrCl analogue, where the resulting polymer with more than 97% ether units was achieved under identical conditions. According to the kinetic data, the apparent activation energy of CHO ring‐opening copolymerization was 9.0 kJ mol^?1. A reasonable polymerization mechanism was proposed based on the interaction between the single‐metal two‐component catalyst system and the monomer. © 2020 Society of Chemical Industry     

Effects of 1,2‐butadiene on the anionic copolymerization of styrene and 1,3‐butadiene in the presence of polar additives

1,2‐Butadiene is shown to be a chain terminating/transferring agent in butyllithium‐initiated diene polymerization. The influence of 1,2‐butadiene on the anionic copolymerization of 1,3‐butadiene and styrene is investigated using n‐butyllithium as initiator and tetrahydrofuran or N,N,N′,N′‐tetramethylethylenediamine as polar additive. A decrease of copolymerization rate is observed on the addition of 1,2‐butadiene. On introducing 1,2‐butadiene, the number average molecular weight (M_n ) decreases and the molecular weight distribution broadens. The vinyl content of copolymer increases slightly with an increase of 1,2‐butadiene. During the copolymerization, 1,2‐butadiene in the presence of a high ratio of polar additives to n‐butyllithium greatly decreases the copolymerization rate, resulting in a lower value of M_n and a narrower molecular weight distribution than that found for a low ratio of polar additives to n‐butyllithium. This evolution can be explained by the base‐catalyzed isomerization of 1,2‐butadiene to form 1‐butylene in the presence of polar additives. With an increasing amount of 1,2‐butadiene, the vulcanized rubber exhibits an increased rolling resistance and a reduced wet skid resistance owing to the decrease of coupling efficiency. These results further indicate the activity of alkynyllithium derivatives produced by the reaction of alkyllithium and 1‐butyne is less than that of the alkyllithium. Copyright © 2007 Society of Chemical Industry     

Influence of chain microstructure on ethylene–norbornene copolymer film properties

The effects of copolymer composition, copolymer composition distribution, and polar α‐olefin incorporation on transparency, refractive index, and hydrophilicity of resultant ethylene–norbornene copolymer films were investigated. It has been found that the transparency is mainly determined by the copolymer composition distribution. The samples having uniform compositions gave better transparency. However, the copolymer composition distribution had little effect on refractive index. The refractive index increased linearly with increasing norbornene content. Furthermore, the incorporation of polar α‐olefin with long carbon chain improved refractive index and hydrophilicity of the films. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Regulating the physical and biological performances of poly(p‐dioxanone) by copolymerization with L‐phenylalanine

The high crystallinity, low solubility in normal solvents, and low hydrophilicity of poly(p‐dioxanone) (PPDO) are unsuitable for the expansion of its biomedical applications. In order to circumvent these problems and induce biological properties, a series of poly(ester amide)s based on p‐(dioxanone) and l ‐phenylalanine were synthesized by copolymerization of p‐dioxanone with l ‐phenylalanine N‐carboxyanhydride monomers. The structures of the copolymers were confirmed by ¹H NMR. The crystallinity of the copolymers was investigated by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). Increasing contents of phenylalanine resulted in decreased crystallinity owing to the rigid phenyl groups of phenylalanine, which disrupted the regularities of the chains, thus confining their movement. The synthesized copolymers were more soluble in chloroform than PPDO. Moreover, the copolymers were more hydrophilic and hydrolyzed more slowly than PPDO, as indicated by water angle contact measurements and in vitro hydrolysis studies. Especially, the copolymers showed inhibition on cell proliferation of L929 mouse fibroblasts by MTT assay, suggesting that the polymers might be useful in the areas where cell proliferation need to be inhabited such as adhesion prevention. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2311–2319, 2013     

Synthesis and characterization of poly(methacrylates) containing spiroacetal and norbornene moieties in side chain

A four‐step synthetic strategy was applied to achieve novel methacrylic monomers. 5‐Norbornene‐2,2‐dimethanol was prepared from a Diels–Alder reaction of cyclopentadiene and acrolein, followed by the treatment of the adduct with an HCHO/KOH/MeOH solution. The resulting 1,3‐diol (1) was then acetalized with different aromatic aldehydes having OH groups on the ring to produce four spiroacetal derivatives. The reaction of methacryloyl chloride with the phenolic derivatives led to four new methacrylic monomers that were identified spectrochemically (mass, FTIR, ¹H‐NMR, and ¹³C‐NMR spectroscopy). Free radical solution polymerization was used to prepare novel spiroacetal–norbornene containing polymethacrylates, which were characterized by FTIR and ¹H‐NMR spectroscopy and differential scanning calorimetry and thermogravimetric thermal analysis. Gel permeation chromatography was performed to determine molecular weight averages and polydispersity. The polymethacrylate having naphthalenic nuclei was recognized to be the highest molecular weight polymer (M̄_n = 12144, η_inh = 0.80 dL/g) with the highest thermal stability. All the polymers showed good solubility in a variety of common organic solvents. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 30–38, 2000     

Poly(hydroxyether of bisphenol A) ‐alt‐polydimethylsiloxane: a novel thermally crosslinkable alternating block copolymer

BACKGROUND: An important strategy for making polymer materials with combined properties is to prepare block copolymers consisting of well‐defined blocks via facile approaches. RESULTS: Poly(hydroxyether of bisphenol A)‐block‐polydimethylsiloxane alternating block copolymers (PH‐alt‐PDMS) were synthesized via Mannich polycondensation involving phenolic hydroxyl‐terminated poly(hydroxyether of bisphenol A), diaminopropyl‐terminated polydimethylsiloxane and formaldehyde. The polymerization was carried out via the formation of benzoxazine ring linkages between poly(hydroxyether of bisphenol A) and polydimethylsiloxane blocks. Differential scanning calorimetry and small‐angle X‐ray scattering show that the alternating block copolymers are microphase‐separated. Compared to poly(hydroxyether of bisphenol A), the copolymers displayed enhanced surface hydrophobicity (dewettability). In addition, subsequent crosslinking can occur upon heating the copolymers to elevated temperatures owing to the existence of benzoxazine linkages in the microdomains of hard segments. CONCLUSION: PH‐alt‐PDMS alternating block copolymers were successfully obtained. The subsequent self‐crosslinking of the PH‐alt‐PDMS alternating block copolymers could lead to these polymer materials having potential applications. Copyright © 2008 Society of Chemical Industry     

A new post‐metallocene catalyst for alkene polymerization: copolymerization of ethylene and 1‐hexene with titanium complexes bearing N,N‐dialkylcarbamato ligands

A new type of post‐metallocene polymerization catalyst based on titanium complexes with N,N‐dialkylcarbamato ligands was used to copolymerize ethylene and 1‐hexene. These easy‐to‐synthesize and stable complexes in combination with different organoaluminium co‐catalysts produce random ethylene/1‐hexene copolymers characterized by a broad molecular weight distribution and high 1‐hexene incorporation, as confirmed by SEC, DSC and ¹³C NMR analysis. The influence of the main reaction parameters on the polymerization reactions was studied including the type of catalyst components, solvent, temperature, the ethylene partial pressure and the [Al]/[Ti] ratio in the catalyst. A higher activity and a higher 1‐hexene incorporation were achieved with AlMe₃‐depleted methylalumoxane as co‐catalyst and chlorobenzene as solvent. © 2013 Society of Chemical Industry     

Facile,Efficient Copolymerization of Ethylene with Bicyclic,Non‐Conjugated Dienes by Titanium Complexes Bearing Bis(β‐Enaminoketonato) Ligands

Copolymerizations of ethylene with 5‐vinyl‐2‐norbornene or 5‐ethylidene‐2‐norbornene under the action of various titanium complexes bearing bis(β‐enaminoketonato) chelate ligands of the type, [R¹NC(R²)CHC(R³)O]₂TiCl₂ ( 1 , R¹=Ph, R²=CF₃, R³=Ph; 2 , R¹=C₆H₄F‐p, R²=CF₃, R³=Ph; 3 , R¹=Ph, R²=CF₃, R³=t‐Bu; 4 , R¹=C₆H₄F‐p, R²=CF₃, R³=t‐Bu; 5 , R¹=Ph, R²=CH₃, R³=CF₃; 6 , R¹=C₆H₄F‐p, R²=CH₃, R³=CF₃), have been shown to occur with the regioselective insertion of the endocyclic double bond of the monomer into the copolymer chain, leaving the exocyclic vinyl double bond as a pendant unsaturation. The ligand modification strongly affects the copolymerization behaviour. High catalytic activities and efficient co‐monomer incorporation can be easily obtained by optimizing the catalyst structures and polymerization conditions.     

One‐step synthesis of bis‐macromonomers of poly(1,3‐dioxolane) catalyzed by Maghnite‐H+

Telechelic poly(1,3‐dioxolane) (PDXL) bis‐macromonomers bearing methyl methacrylate end groups were prepared by cationic ring‐opening polymerization of 1,3‐dioxolane (DXL), in the presence of methacrylic anhydride, catalyzed by Maghnite‐H⁺ (Mag‐H⁺), in bulk and in solution. Maghnite is a montmorillonite sheet silicate clay, which exchanged with protons to produce Mag‐H⁺. The influence of the amount of Mag‐H⁺, monomer (DXL), and methacrylic anhydride on monomer conversion was studied. The polymerization yield and the molecular weight of α,ω‐bis‐unsaturated PDXLs prepared depend on the amount of Mag‐H⁺ used and the reaction time. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Syndiospecific polymerization of styrene based on dichlorobis(1,3‐diketonato)titanium/methylaluminoxane catalyst system: effects of substituents on catalyst activity

Dichlorobis(substituted‐1,3‐diketonato)titanium complexes 4a–e have been synthesized and were combined with methylaluminoxane as cocatalyst to be employed in the polymerization of styrene. The polystyrenes produced have high syndiotacticities of 94.0–98.2%. The substituents at either 2‐ or 1,3‐positions of 1,3‐diketones can noticeably influence catalyst activities. The catalytic activities of 4a–c bearing 2‐substituents and 4e bearing 1,3‐diphenyl groups are tenfold higher than that of 4d bearing 1,3‐dimethyl groups. The effects of polymerization conditions on the catalyst activities and the syndiotacticities of the polystyrene produced have been examined. © 2000 Society of Chemical Industry