Temperature‐dependent fluorescence from pyrenyl‐modified polyethylene films. A comparison of attachment methods and morphology changes by irradiation with eV‐range photons and bombardment with MeV‐range positive ions

1‐Pyrenyl groups were attached covalently to three polyethylene ( Py–PE ) films with different crystallinities by irradiating (eV‐range photons–UV‐photons) or by bombarding (MeV‐range ions–protons and alpha particles) pyrene‐doped PE films ( Py/PE ). Onset temperatures of relaxation processes (T_x) of the Py–PE were approximated from (1) Arrhenius‐type plots of the normalized integrated intensities of the films and (2) the temperature dependence of the full‐width half‐maximum (FWHM) films and the position of the 0–0 fluorescence band. DSC thermograms of the native and irradiated or bombarded films were also compared to independently assess the morphological changes. The onset temperatures T_x in lower crystallinity Py–PE films were more difficult to locate when prepared by bombardment with high doses than with low doses of photons or ions or by irradiation. The ease of locating the T_x in higher crystallinity Py–PE films was independent of dose, suggesting little change in the mobility in the vicinity of pyrenyl probes. Fluorescence from Py–PE bombarded with alpha particles indicated the presence of both singly‐ and doubly‐attached pyrenyl groups. The singly‐attached pyrenyl groups were less sensitive than the doubly attached to the T_x. Py–PE films were more sensitive luminescence reporters of T_γ segmental motions than were 9‐anthryl groups covalently attached to the same polymers. We also discuss possible reasons why the values of the activation energies for the relaxation processes, as calculated from the Arrhenius plots, were much smaller than those based on the dynamic mechanical methods. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2957–2970, 2004     

Grignard condensation routes to 1,3‐disilacyclobutane‐containing cyclolinear polycarbosilanes

Alkylene‐ and arylene‐bridged cyclolinear polycarbosilanes (CLPCS) with 1,3‐disilacyclobutane (DSCB) rings incorporated in the main chain of the polymer were prepared by polycondensation between corresponding di‐functional DSCB derivatives and di‐Grignard reagents. Well‐defined, low molecular weight (M_n = 3–5K; DP = 17–26), hexylene‐ and phenylene‐bridged CLPCS polymers were obtained without appreciable ring opening of the DSCB rings. Large exothermic peaks were observed in the DSC for these CLPCSs, which indicated, along with the IR spectra, that crosslinking occurred on heating to about 250 °C via the ring opening of the embedded, alternating, DSCB rings. Moreover, PB‐CLPCS undergoes photochemically induced crosslinking on UV irradiation to form crosslinked polycarbosilane network films. The spin‐cast, cured, films of these CLPCSs exhibit relatively low dielectric constants and promising thermal and mechanical properties for applications in electronics, for example, directly UV‐photoimprinted low‐k dielectrics. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1547–1557     

Preparation of Polyethylene/Graphene Nanocomposites with Octadecylamine‐Modified Graphene Oxide‐MgCl‐Supported Ziegler–Natta Catalyst

In this work, an octadecylamine‐modified graphene oxide (ODA‐GO)‐MgCl‐supported Ziegler–Natta catalyst was synthesized by reacting ODA‐GO with a Grignard reagent, followed by anchoring TiCl₄ to the structure. The effect of the ODA‐GO on the catalyst morphology and ethylene polymerization behavior was examined. The resultant polyethylene (PE)/ODA‐GO nanocomposites directly mirrored the catalyst morphology by forming a layered morphology, and the ODA‐GO fillers were well dispersed in the PE matrix and showed strong interfacial adhesion with it. The resultant PE/ODA‐GO nanocomposites exhibited better thermal stability and mechanical properties than neat PE, even with a small amount of ODA‐GO added. Thus, this work provides a facile approach to the production of high‐performance PE. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 855–860     

Synthesis of well‐defined polymers end‐functionalized with crosslinkable aziridine groups by living anionic polymerization

Well‐defined end‐functionalized polystyrene, poly(α‐methylstyrene), and polyisoprene with polymerizable aziridine groups were synthesized by the termination reactions of the anionic living polymers of styrene, α‐methylstyrene, and isoprene with 1‐[2‐(4‐chlorobutoxy)ethyl]aziridine in tetrahydrofuran at ?78 °C. The resulting polymers possessed the predicted molecular weights and narrow molecular weight distributions (weight‐average molecular weight/number‐average molecular weight < 1.1) as well as aziridine terminal moieties. The cationic ring‐opening polymerization of the ω‐monofunctionalized polystyrene having an aziridinyl group with Et₃OBF₄ gave the polymacromonomer, whereas the α,ω‐difunctional polystyrene underwent crosslinking reactions to afford an insoluble gel. Crosslinking products were similarly obtained by the reaction of the α,ω‐diaziridinyl polystyrene with poly(acrylic acid)‐co‐poly(butyl acrylate). © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4126–4135, 2005     

Electrochemical polymerization of imidazolum‐ionic liquids bearing a pyrrole moiety

A series of imidazolium‐based ionic liquid monomers bearing a terminal pyrrole moiety were synthesized and electrochemically polymerized. It is found that the polymerizability of the synthesized ionic liquids is strongly dependent on the type of the counteranions. Although bromide monomer is not polymerizable, well‐defined polymeric films can be formed on various substrates in the cases of flour‐containing anions (BF₄^?, PF₆^?). The performed characterizations show that all resulting polypyrrole films are electroactive, and the imidazolium‐based ionic liquid moieties are correctly incorporated in polymer films during the electropolymerization process. This work not only provides a facile new method to immobilize ionic liquids on solid surface. Interestingly, without use of any template unique “knit” morphology and nanostructure, even hierarchical structures could also be produced by the electropolymerization of these new functionalized pyrrole monomers. We found that the properties of the pendant ionic liquid units on the surface of the formed polymer films preserved, and by simple anion exchange their surface energy and tension could be easily tuned without loss of the electrical, optical properties, and morphology of the polypyrrole films. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4151–4161, 2008     

Synthesis and characterization of poly(isobutylene‐co‐isoprene)‐derived macro‐monomers

Allylic halide displacement from brominated poly(isobutylene‐co‐isoprene) (BIIR) by carboxylate nucleophiles is used to prepare elastomer derivatives containing pendant polymerizable functionality. These solvent‐borne substitutions are conducted under homogeneous and phase‐transfer catalyzed reaction conditions to synthesize acrylate and vinylbenzoate esters in high yield. The resulting macro‐monomer derivatives are shown to crosslink efficiently with peroxide initiation to give high modulus, thermoset products that cannot otherwise be accessed from isobutylene‐rich elastomers. The extent of cure, as measured by the storage modulus of the vulcanizate, scales with RCH=CH₂ content, and can be extended by co‐oligomerization of pendant unsaturation with that contained within multifunctional coagents. An alternate approach involving the introduction of pendant sulfonyl azide functionality is described, wherein thermal decomposition to nitrene intermediates supports an efficient crosslinking process. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Thermal behavior of poly(vinylbenzyl chloride)‐grafted poly(ethylene‐co‐tetrafluoroethylene) films

The effect of the degree of grafting (DOG) on the thermal behavior of poly(vinylbenzyl chloride)‐grafted poly(ethylene‐co‐tetrafluoroethylene) (ETFE‐g‐PVBC) films was investigated by differential scanning calorimetry (DSC), X‐ray diffraction (XRD), dynamic mechanical analysis ( DMA), FT‐IR, and thermogravimetric analysis (TGA) instruments. Several ETFE‐g‐PVBC films with various degrees of grafting, including 10, 24, 41, 60, and 94%, were prepared using a radiation grafting technique. The DSC and XRD results of the ETFE‐g‐PVBC films revealed that the crystallinity of the films decreased as the DOG increased. The DMA and FT‐IR results of the films indicated that a crosslinking reaction occurred at temperatures above 250 °C. In the thermal properties of the grafted films, an increase in the DOG led to an increase in the decomposition temperature. The activation energy (E_a) of the thermal decomposition was calculated using Kissinger's equation from TGA results. The E_a value of the PVBC graft chain was found to increase as the DOG increased, indicating that the crosslinking reaction of ETFE‐g‐PVBC films increased with an increase in the DOG during the thermal degradation process. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 517–525     

Highly Stereoselective β‐Mannopyranosylation via the 1‐α‐Glycosyloxy‐isochromenylium‐4‐gold(I) Intermediates

While the gold(I)‐catalyzed glycosylation reaction with 4,6‐O‐benzylidene tethered mannosyl ortho‐alkynylbenzoates as donors falls squarely into the category of the Crich‐type β‐selective mannosylation when Ph₃PAuOTf is used as the catalyst, in that the mannosyl α‐triflates are invoked, replacement of the ^?OTf in the gold(I) complex with less nucleophilic counter anions (i.e., ^?NTf₂, ^?SbF₆, ^?BF₄, and ^?BAr₄^F) leads to complete loss of β‐selectivity with the mannosyl ortho‐alkynylbenzoate β‐donors. Nevertheless, with the α‐donors, the mannosylation reactions under the catalysis of Ph₃PAuBAr₄^F (BAr₄^F=tetrakis[3,5‐bis(trifluoromethyl)phenyl]borate) are especially highly β‐selective and accommodate a broad scope of substrates; these include glycosylation with mannosyl donors installed with a bulky TBS group at O3, donors bearing 4,6‐di‐O‐benzoyl groups, and acceptors known as sterically unmatched or hindered. For the ortho‐alkynylbenzoate β‐donors, an anomerization and glycosylation sequence can also ensure the highly β‐selective mannosylation. The 1‐α‐mannosyloxy‐isochromenylium‐4‐gold(I) complex ( Cα ), readily generated upon activation of the α‐mannosyl ortho‐alkynylbenzoate ( 1 α ) with Ph₃PAuBAr₄^F at ?35 °C, was well characterized by NMR spectroscopy; the occurrence of this species accounts for the high β‐selectivity in the present mannosylation.     

Improved Synthesis of the [Ru(η6‐p‐cymene)Cl3] Anion: Facile Isolation under Mild Conditions

Reaction of [Ru(η⁶‐p‐cymene)Cl₂]₂ with two equivalents of [Ph₄P][Cl] in CH₂Cl₂ yields [Ph₄P][Ru(η⁶‐p‐cymene)Cl₃], containing a trichlororuthenate(II) anion. In solution, an equilibrium between the product and [Ru(η⁶‐p‐cymene)Cl₂]₂ is observed, which in CDCl₃ is nearly completely shifted to the dimer, whereas in CD₂Cl₂ essentially a 1:1‐mixture of the two ruthenium species is present. Crystallization from CH₂Cl₂/pentane yielded two different crystals, which were identified by X‐ray analysis as [Ph₄P][Ru(η⁶‐p‐cymene)Cl₃] and [Ph₄P][Ru(η⁶‐p‐cymene)Cl₃]·CH₂Cl₂.     

Synthesis and Chloride Affinity of Sterically Demanding Ditopic Lithium Bis(pyrazol‐1‐yl)borates

The synthesis and full characterization of the sterically demanding ditopic lithium bis(pyrazol‐1‐yl)borates Li₂[p‐C₆H₄(B(Ph)pz^R₂)₂] is reported (pz^R = 3‐phenylpyrazol‐1‐yl ( 3 ^Ph), 3‐t‐butylpyrazol‐1‐yl ( 3 ^tBu)). Compound 3 ^Ph crystallizes from THF as THF‐adduct 3 ^Ph(THF)₄ which features a straight conformation with a long Li···Li distance of 12.68(1) Å. Compound 3 ^tBu was found to function as efficient and selective scavenger of chloride ions. In the presence of LiCl it forms anionic complexes [ 3 ^tBuCl]⁻ with a central Li‐Cl‐Li core (Li···Li = 3.75(1) Å).     

Synthesis of well‐defined and end‐polymerizable star‐shaped polysulfides and their application to negative photoresist

Various star‐shaped poly(phenoxy propylene sulfide)s (PPSs) bearing curable end groups were synthesized by the functionalization of the propagating ends of star‐shaped poly(PPS) with various electrophilies. The functionalization with chloromethyl styrene proceeded quantitatively, and afforded polymers with M_n almost agreed with theoretical value and narrow M_w/M_n. The photocuring conditions were optimized, and the addition of 10 wt % of poly(ethylene glycol) diacrylate was effective to attain sufficient crosslinking. The photocuring reaction of the end‐functionalized poly(PPS) films cast on silicon wafers was conducted by UV irradiation. The cured poly (PPS)s became insoluble in THF, supporting the sufficient crosslinking. Developing of a cured polymer yielded a negative photoresist pattern. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Well‐defined non‐linear polyethylene‐based macromolecular architectures

Polyethylene (PE)‐based 3‐ and 4‐miktoarm star [PE(PCL)₂, PE(PCL)₃] and H‐type [(PCL)₂PE(PCL)₂] block copolymers [polycaprolactone (PCL)] were synthesized by a combination of polyhomologation, chlorosilane chemistry, and ring opening polymerization (ROP). The following steps were used for the synthesis of the miktoarm stars: (a) reaction of a hydroxy‐terminated polyethylene (PE‐OH), prepared by polyhomologation of dimethylsulfoxonium methylide with a monofunctional boron initiator followed by oxidation/hydrolysis, with chloromethyl(methyl)dimethoxysilane or chloromethyltrimethoxysilane; (b) hydrolysis of the produced ω‐di(tri)methoxysilyl‐polyethylenes to afford ω‐dihydroxy‐polyethylene (difunctional initiator) and ω‐trihydroxy‐polyethylene (trifunctional initiator); and (c) ROP of ɛ‐caprolactone with the difunctional (3‐miktoarm star) or trifunctional macroinitiator (4‐miktoarm star), in the presence of 1‐tert‐butyl‐2,2,4,4,4‐pentakis(dimethylamino)‐2λ⁵,4λ⁵‐catenadi(phosphazene) (t‐BuP₂). The H‐type block copolymers were synthesized using the same strategy, but with a difunctional polyhomologation initiator. All intermediates and final products were characterized by HT‐GPC, ¹H NMR and FTIR analyses. Thermal properties of the PE precursors and all final products were investigated by DSC and TGA. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2129–2136     

Synthesis,characterization, and applications in photovoltaic cells of oxetane‐functionalized P3HT derivatives

Several crosslinkable oxetane‐functionalized copolymers, containing regio‐regular segments of 3‐hexylthiophene, are synthesized using the Grignard metathesis polymerization. The optical and electrochemical properties of the new polymers, both in the soluble and crosslinked forms, are reported. These polymers are used in the preparation of organic photovoltaics upon blending with PCBM as electron‐acceptor. The effect of the crosslinking of these copolymers, once the blend films are formed, on the devices performance is also studied. In particular, the insertion of the oxetane‐functionalized thiophene comonomers leads to a decrease of the devices performance, which is further decreased upon crosslinking of the copolymer. However, the stability of the devices overall improves upon crosslinking of the copolymer. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 652–663     

Boron as a Powerful Reductant: Synthesis of a Stable Boron‐Centered Radical‐Anion Radical‐Cation Pair

Despite the fundamental importance of radical‐anion radical‐cation pairs in single‐electron transfer (SET) reactions, such species are still very rare and transient in nature. Since diborenes have highly electron‐rich B? B double bonds, which makes them strong neutral reductants, we envisaged a possible realization of a boron‐centered radical‐anion radical‐cation pair by SET from a diborene to a borole species, which are known to form stable radical anions upon one‐electron reduction. However, since the reduction potentials of all know diborenes (E_1/2=?1.05/?1.55 V) were not sufficiently negative to reduce MesBC₄Ph₄ (E_1/2=?1.69 V), a suitable diborene, IiPr?(iPr)B?B(iPr)?IiPr, was tailor‐made to comply with these requirements. With a halfwave potential of E_1/2=?1.95 V, this diborene ranks amongst the most powerful neutral organic reductants known and readily reacted with MesBC₄Ph₄ by SET to afford a stable boron‐centered radical‐anion radical‐cation pair.     

Free radical initiated low temperature crosslinking of phenylethynyl (PE) end‐capped oligomides

A relatively low‐temperature crosslinking method for phenylethynyl (PE) end‐capped oligomides was developed. PE end‐capped oligomides are typically cured into crosslinked polyimides at 370 °C for about 1 h. The addition of a low viscosity mixed‐solvent of N‐methylpyrrolidinone (NMP)/dimethyl ether of polyethylene glycol (M = 250 g/mol), NMP/DM‐PEG‐250, or NMP/polyethylene glycol (M = 400 g/mol), NMP/PEG‐400, as film forming medium for PE‐end‐capped oligomides was investigated. Fourier transform infrared spectroscopy and ¹³C NMR showed that the mixed solvent addition was effective for achieving low‐temperature crosslinking of the ethynyl end‐caps over the temperature range 200–250 °C. The low temperature crosslinking process was explained by thermolysis of the PEG molecules over this temperature range forming free radical species such as ～CH₂CH₂O· or ～CH₂CH₂^· which initiate cure of the ethynyl groups resulting in a cross linked polyimide membrane. The PEG solvents also provide a radical source for the degradation polymerization of the solvents to a water and NMP insoluble polymer, which formed a miscible blend with the crosslinked membrane. Glass transition temperature (differential scanning calorimetry) data and thermo gravimetric analysis data provide evidence for the miscible blend. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3950–3963, 2010.     

Fluorene‐rich high performance polyesters: Synthesis and characterization of 9,9‐fluorenylidene and 2,7‐fluorenylene‐based polyesters with excellent optical property

Polyesters PEs containing high content of fluorene units in their backbones were synthesized from 9,9‐diarene‐substituted fluorene diols ( 1 ) and fluorene‐based diacid chlorides ( 2 ) by high temperature polycondensation at 185 °C in diphenyl ether. The molecular weights of the polyesters PE1‐PE5 were in a range of M_w 25,000–165,000. The polyesters displayed their high thermostability: the glass transition temperatures (T_g) by differential scanning calorimetry analysis ranged from 109 to 217 °C, while the 10% weight loss temperatures (T_d10) measured by thermogravimetric analysis were over 400 °C in nitrogen and 395 °C in air. The polyesters had good solubility in most common organic solvents such as chloroform and toluene and gave tough, transparent and flexible cast films. The transmittance of the films was over 80% in the wavelength range from 450 to 700 nm in any PEs . The PEs exhibited high refractive index values around 1.65, while they had very low degree of birefringence. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2549–2556, 2008     

Photochemical reactions of quaternary ammonium dithiocarbamates as photobase generators and their use in the photoinitiated thermal crosslinking of poly(glycidyl methacrylate)

The photochemical behavior of quaternary ammonium salts (QA salts) with N,N‐dimethyldithiocarbamate as photobase generators and the photoinitiated thermal crosslinking of poly(glycidyl methacrylate) (PGMA) with the QA salts were investigated. The formation of basic compounds in the photolysis of 1‐phenacyl‐(1‐azonia‐4‐azabicyclo[2,2,2]octane) N,N‐dimethyldithiocarbamate was ascertained by the color change of phenol red as an acid–base indicator. ¹H NMR spectra of photoproducts in CDCl₃ under N₂ showed that the photolysis of 1‐naphthoylmethyl‐(1‐azonia‐4‐azabicyclo[2,2,2]octane) N,N‐dimethyldithiocarbamate resulted in the quantitative formation of triethylenediamine and a dithiocarbamate derivative. The presence of oxygen in the photolysis decreased the photolysis rate. The amine was also detected in its photolysis in polystyrene films. The effects of ammonio groups and counteranions of QA salts on the photoinitiated thermal crosslinking of PGMA films were also investigated. Quaternary ammonium dithiocarbamates acted as excellent photobase generators and effective photoinitiated thermal crosslinkers for PGMA. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1329–1341, 2001     

Synthesis and Electroluminescence of Metal 4‐Styryl‐8‐hydroxyquinolates

Aluminum and zinc complexes of 4‐substituted 8‐hydroxyquinoline were used effectively as emissive materials in light‐emitting diodes (LED). The substituents chosen in this study were p‐methoxy‐2‐styryl, p‐diethylamino‐2‐styryl, and naphthalene‐2‐vinyl groups. Their emission spectra were red‐shifted with respect to that of aluminum tris(hydroxylquinolate) (Alq₃) as a result of extending their π‐conjugation. All complexes formed amorphous glasses, which exhibited high thermal and electrical stability. Typical LED devices were fabricated by mixing the dyes with polyvinylcarbazole and spin‐coated to form thin films, which were sandwiched between ITO (indium tin oxide) and a metal electrode. These devices displayed yellow‐orange emissions with quantum efficiency ca. 0.4%.     

Diblock copolymer–azobenzene complexes through hydrogen bonding: Self‐assembly and stable photoinduced optical anisotropy

We have demonstrated the preparation of a series of photoaddressable supramolecular block copolymers by mixing a carboxy‐terminated azobenzene derivative, 6‐[4‐(4′‐cyanophenylazo)phenyloxy]hexanoic acid (AZO), and two polystyrene‐b‐poly(4‐vinylpiridine) (PS‐b‐P4VP) block copolymers. AZO can be selectively attached to the P4VP block of PS‐b‐P4VP through hydrogen bonding interactions. The assembly of AZO with vinylpyridine group‐containing polymers was initially investigated on a model system composed of P4VP homopolymer and AZO. Homogeneous liquid crystalline materials were obtained for ratios of AZO to vinylpyridine repeating unit, x, lower or equal to 0.50. Mixtures with higher x resulted in heterogeneous materials showing clear macrophase separation. Accordingly, a series of hydrogen‐bonded complexes of PS‐b‐P4VP and AZO, PS‐b‐P4VP(AZO)_x, with x = 0.25 and x = 0.50 were prepared. Lamellar and spherical morphologies were observed for the complexes based on PS24‐b‐P4VP9.5 (M_n,PS = 24,000, M_n,P4VP = 9500) and PS24‐b‐P4VP1.9 (M_n,PS = 24,000, M_n,P4VP = 1900), respectively. Photoinduced orientation of the azobenzene units was obtained in films of P4VP(AZO)_x and PS‐b‐P4VP(AZO)_x with x = 0.25 and 0.50 by using 488 nm linearly polarized light and characterized through birefringence and dichroism measurements. This investigation shows a versatile and less laborious approach to azobenzene‐containing polymer materials with low chromophore content, of interest in optical application. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Catalytic synthesis of styryl‐capped isotactic polypropylenes

Bis‐styrenic molecules, 1,4‐divinylbenzene (DVB) and 1,2‐bis(4‐vinylphenyl)ethane (BVPE), were successfully combined with hydrogen (H₂) to form consecutive chain transfer complexes in propylene polymerization mediated by an isospecific metallocene catalyst (i.e., rac‐dimethylsilylbis(2‐methyl‐4‐phenylindenyl)zirconium dichloride, I ) activated with methylaluminoxane (MAO), rendering a catalytic access to styryl‐capped isotactic polypropylenes (i‐PP). The chain transfer reaction took place in a unique way where prior to the ultimate chain transfer DVB/H₂ or BVPE/H₂ caused a copolymerization‐like reaction leading to the formation of main chain benzene rings. A preemptive polymer chain reinsertion was deduced after the consecutive actions of DVB/H₂ or BVPE/H₂, which gave the styryl‐terminated polymer chain alongside a metal‐hydride active species. It was confirmed that the chain reinsertion occurred in a regio‐irregular 1,2‐fashion, which contrasted with a normal 2,1‐insertion of styrene monomer and ensured subsequent continuous propylene insertions, directing the polymerization to repeated DVB or BVPE incorporations inside polymer chain. Only as a competitive reaction, the insertion of propylene into metal‐hydride site broke the chain propagation resumption process while completed the chain transfer process by releasing the styryl‐terminated polymer chain. BVPE was found with much higher chain transfer efficiency than DVB, which was attributed to its non‐conjugated structure with much divided styrene moieties resulting in higher polymerization reactivity but lower chain reinsertion tendency. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3709–3713, 2010