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Improvement of mechanical stability for porous polymer monoliths is one of the prime concerns as represented by the long‐standing research efforts on resorcinol‐formaldehyde (RF) aerogels. To this end, it is imperative not only to tailor mechanically robust porous morphology but also to design macromolecular structure of polymer scaffolds. Previously, we have developed porous RF gels showing a unique mechanical feature combining high mechanical strength and outstanding flexibility against uniaxial compression. Comparison of mechanical properties between the porous gels with varied morphologies has elucidated the influence of porous structure, whereas effects of macromolecular structure still remain elusive. Herein, we have fabricated a series of macroporous phenolic resins from three types of linear prepolymers with phenol pendant groups, poly(4‐vinylphenol) or poly(4‐hydroxystyrene), which differ in molecular‐weight properties, by the sol–gel process in conjunction with spinodal decomposition. The difference in gelation and phase separation behaviors observed for the discrete systems indicates the dissimilar cross‐linked networks developed in the respective gels, which consequently influence the mechanical strength and flexibility against uniaxial compression. This study also demonstrates the improvement of mechanical features by thermal treatment for the porous monoliths derived from the high‐molecular‐weight prepolymer with a view to the application in mechanical energy absorption. [ABSTRACT FROM AUTHOR]

In this work, poly(α-methyl styrene) (PAMS) was synthesized through living anionic polymerization and characterized by 13C NMR, 1H NMR, GPC, TGA, DSC. The kinetics study was performed using multi-stage dosing of initiator. The results obtained via GPC analysis revealed that polydispersity index of the synthesized PAMS was close to the true value. Moreover, multi-stage dosing of initiator offers valuable and accurate method to determine propagation rate constant and initial impurities value of the system. 13C NMR analysis demonstrated that Bernoullian statics model exhibits a superior fit compared to 1st -order Markov statics model for the assigned sequence. Furthermore, the synthesized PAMS presents higher degree of racemic addition with Pm=0.439. 1H NMR spectroscopy was utilized to ascertain number-average molecular weight of the synthesized samples, corroborating the values estimated through GPC analysis. From the thermal analysis, it was shown that PAMS containing very low molecular weight demonstrates negative glass transition temperature and broad thermal decomposition range. [ABSTRACT FROM AUTHOR]

Innovative strides in polymer synthesis have led to the successful living anionic polymerization of styrene-olefin triblock copolymers, yielding varying molecular weights and a remarkably narrow dispersity (Đ) in cyclohexane solvent at 45°C, initiated by n-butyllithium. The novel approach employs anionic polymerization, augmented by the aid of a coupling agent known as 1,12-dibromododecane. Unlike traditional alcohol-based methods employed in polystyrene synthesis, this coupling agent, introduced at the end of the reaction, grafts two living macro-styrene chains with the dodecane chain, effectively acting as the pivotal second component in the formation of the triblock copolymer. Extensive experimentation pinpointed 45°C as the optimal temperature for anionic copolymerization in cyclohexane solvent. The comprehensive analysis, encompassing 13C NMR, 1H NMR, FTIR spectroscopy, and GPC, confirms the successful synthesis of styrene-dodecane-styrene triblock copolymer. The NMR results illustrate successful molecular structures, while GPC attests to the precision, showing a narrow Đ of below 1.2. This pioneering approach not only underscores the efficiency of anionic polymerization in the synthesis of styrene-olefin-styrene triblock copolymer using termination strategy but also promises extensive implications in material science and industrial applications.

Graft copolymers have unique application scenarios in the field of high-performance thermoplastic elastomers, resins and rubbers. β-myrcene (My) is a biomass monomer derived from renewable plant resources, and its homopolymer has a low glass transition temperature and high elasticity. In this work, a series of tapered copolymers P(My-co-AMS)k (k = 1, 2, 3) were first synthesized in cyclohexane by one-pot anionic polymerization of My and α-methyl styrene (AMS) using sec-BuLi as the initiator. PAMS chain would fracture when heated at high temperature and could endow the copolymer with thermal degradation property. The effect of the incorporation of AMS unit on the thermal stability and glass transition temperature of polymyrcene main chain was studied. Subsequently, the double bonds in the linear copolymers were partially epoxidized and hydroxylated into hydroxyl groups to obtain hydroxylated copolymer, which was finally used to initiate the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) to synthesize the graft copolymer with PCL as the side chain. All these copolymers before and after modifications were characterized by proton nuclear magnetic resonance (1H NMR), gel permeation chromatography (GPC), thermogravimetry analysis (TGA), and differential scanning calorimeter (DSC). [ABSTRACT FROM AUTHOR]

I nnovative strides in polymer synthesis have led to the successful living anionic polymerization of styrene-olefin triblock copolymers, yielding varying molecular weights and a remarkably narrow dispersity (Đ) in cyclohexane solvent at 45°C, initiated by n-butyllithium. The novel approach employs anionic polymerization, augmented by the aid of a coupling agent known as 1,12-dibromododecane. Unlike traditional alcohol-based methods employed in polystyrene synthesis, this coupling agent, introduced at the end of the reaction, grafts two living macro-styrene chains with the dodecane chain, effectively acting as the pivotal second component in the formation of the triblock copolymer. Extensive experimentation pinpointed 45°C as the optimal temperature for anionic copolymerization in cyclohexane solvent. The comprehensive analysis, encompassing 13C NMR, ¹H NMR, FTIR spectroscopy, and GPC, confirms the successful synthesis of styrene-dodecane-styrene triblock copolymer. The NMR results illustrate successful molecular structures, while GPC attests to the precision, showing a narrow Đ of below 1.2. This pioneering approach not only underscores the efficiency of anionic polymerization in the synthesis of styreneolefin-styrene triblock copolymer using termination strategy but also promises extensive implications in material science and industrial applications. [ABSTRACT FROM AUTHOR]

Metallopolymers with precise structures and particular properties have emerged as promising functional materials. The applications of metallopolymers depend on the unique characteristics of the metal centers (such as electronic, optical, magnetic, redox, etc.) and the superior mechanical and processing performances of classical polymers. Access to accurately design metallopolymers with well-defined structures and chemical compositions has enabled researchers to detailedly investigate their performances and a series of advanced applications. Along with the rapid development of modern synthetic chemistry and polymerization techniques, various functional metallopolymers have been synthesized largely and have shown many potential applications. Especially, controlled polymerizations, including ATRP, RAFT, ROMP, living anionic polymerization, and so on, are currently attracting considerable attention for the synthesis of well-defined metallopolymers. These polymerizations have become versatile and powerful synthetic tools, which enable the synthesis of new metallopolymers with accurately controlled molecular weight, relatively narrow molecular weight distribution, composition (block, graft, alternating gradient copolymers), and various functionalities. In this review, we highlight the most recent progress on the controlled synthesis of various well-defined metallopolymers. The review summarizes the recent progress on controlled polymerizations (such as ATRP, RAFT, ROMP, living anionic polymerization, etc.) for various well-defined metallopolymers, and these polymerizations enable the synthesis of novel metallopolymers with accurately controlled molecular weight, relatively narrow molecular weight distribution, composition (block, graft, alternating gradient copolymers), and diverse functionalities. [ABSTRACT FROM AUTHOR]

Well controlled living anionic polymerization of vinyl monomers was achieved by using the initiator system composed of desilylation of benzyltrimethylsilane (BnTMS) by potassium tert‐butoxide (t‐BuOK) in tetrahydrofuran and trapping the resulting benzyl anion with α‐methylstyrene or 1,1‐diphenylethylene in the initiator system in order to control the desilylation and polymerization reaction. This method led to high initiation efficiency and strict control of molecular weights of the obtained polymers. Furthermore, the initiator system could be applied to the synthesis of a block copolymer of PMMA‐b‐PtBMA. These results showed that living nature of the polymer obtained using BnTMS/t‐BuOK initiator system in the presence of the appropriate additives. [ABSTRACT FROM AUTHOR]

Graft copolymers have unique application scenarios in the field of high-performance thermoplastic elastomers, resins and rubbers. β-myrcene (My) is a biomass monomer derived from renewable plant resources, and its homopolymer has a low glass transition temperature and high elasticity. In this work, a series of tapered copolymers P(My-co-AMS)k (k = 1, 2, 3) were first synthesized in cyclohexane by one-pot anionic polymerization of My and α-methyl styrene (AMS) using sec-BuLi as the initiator. PAMS chain would fracture when heated at high temperature and could endow the copolymer with thermal degradation property. The effect of the incorporation of AMS unit on the thermal stability and glass transition temperature of polymyrcene main chain was studied. Subsequently, the double bonds in the linear copolymers were partially epoxidized and hydroxylated into hydroxyl groups to obtain hydroxylated copolymer, which was finally used to initiate the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) to synthesize the graft copolymer with PCL as the side chain. All these copolymers before and after modifications were characterized by proton nuclear magnetic resonance (1H NMR), gel permeation chromatography (GPC), thermogravimetry analysis (TGA), and differential scanning calorimeter (DSC).

Copyright of Polymer Materials Science & Engineering is the property of Sichuan University, Polymer Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We report the first anionic polymerization of 1‐vinylcyclohexene (VCH). This structure may be considered as an intermediate between dienes and styrene. The polymerization of this cyclic 1,2‐disubstituted 1,3‐diene proceeded quantitatively in cyclohexane at 25 °C with sec‐butyllithium as an initiator. The obtained polymers have well‐controlled molecular weights in the range of 5 to 142 kg mol−1, controlled by the molar ratio of monomer and initiator, with narrow molecular weight distributions (Đ<1.07–1.20). In situ 1H NMR kinetic characterization revealed a weak gradient structure for the copolymers of styrene and VCH, (rSty=2.55, rVCH=0.39). P(VCH) obtained in cyclohexane with sec‐BuLi as an initiator showed both 1,4‐ and 3,4‐incorporation mode (ratio: 64 : 36). It was demonstrated that the microstructure of the resulting P(VCH) can be altered by the addition of a modifier (THF), resulting in increasing 3,4‐microstructure (up to 78 %) and elevated glass‐transition temperature up to 89 °C. Thus, the monomer VCH polymerizes carbanionically like a diene, however leading to rigid polymers with high glass transition temperature, which provides interesting options for combination with other dienes to well‐defined polymer architectures and materials. [ABSTRACT FROM AUTHOR]

Wir berichten über die erste anionische Polymerisation von 1‐Vinylcyclohexen (VCH). Diese Struktur kann als eine Kombination von Dien und Styrol betrachtet werden. Die Polymerisation dieses zyklischen, 1,2‐disubstituierten 1,3‐Diens verlief quantitativ in Cyclohexan bei 25 °C mit sec‐Butyllithium als Initiator. Die erhaltenen Polymere wiesen gut kontrollierte Molekulargewichte im Bereich von 5 bis 142 kg mol−1 auf, die durch das molare Verhältnis von Monomer und Initiator einstellbar waren, mit engen Molekulargewichtsverteilungen (Đ<1.07–1.20). Die kinetische in situ Untersuchung der Polymerisation mittels 1H NMR ergab eine schwach ausgeprägte Gradientenstruktur für die Copolymere von Styrol und VCH (rSty=2.55, rVCH=0.39). PVCH, das in Cyclohexan mit sec‐BuLi als Initiator erhalten wurde, zeigte sowohl 1,4‐ als auch 3,4‐Einbau von VCH (Verhältnis: 64 : 36). Es wurde weiterhin gezeigt, dass die Mikrostruktur des resultierenden PVCH durch Zugabe eines polaren Additivs (THF) verändert werden kann, was zu einem erhöhten Anteil der 3,4‐Mikrostruktur (bis zu 78 %) und einer erhöhten Glasübergangstemperatur von bis zu 89 °C führte. Somit polymerisiert das Monomer VCH carbanionisch lebend wie ein Dien, liefert dabei jedoch recht rigide Polymere mit hoher Glasübergangstemperatur, was interessante Möglichkeiten für die Kombination mit anderen Dienen zu hoch definierten Polymerarchitekturen und Materialien bietet. [ABSTRACT FROM AUTHOR]

Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Block solution-polymerized styrene-butadiene rubber (SSBR) with two different compositions and ratios was designed and synthesized by living anionic polymerization with styrene and butadiene as monomers, n-butyllithium as initiator, 2,2-bis(tetrahydrofuran)propane as modifier, and cyclohexane as solvent. The microstructure, chemical composition and molecular weight and its distribution of the block SSBR were characterized by proton nuclear magnetic resonance spectrometer and gel permeation chromatographer, and the mechanical properties and dynamic mechanical properties of the block SSBR vulcanizate were analyzed by rubber tension machine and dynamic mechanical analyse respectively. The results showed that the molecular structure of the block SSBR met the desired molecular structure. The vulcanizate had good mechanical properties and dynamic mechanical properties. The higher the mass ratio of the soft block to the hard block of the block SSBR, the wider the damping temperature range. As the soft block had lower bound styrene content, the damping temperature range of the block SSBR was more widened. When mass fraction of bound styrene of the two blocks of block SSBR was 15% and 50%, and the mass ratio was 7/3, the efficient damping temperature range exceeded 53 ℃ with loss factor of not less than 0.3.

A series of polystyrene macromonomers were synthesized by living anionic polymerization technique using styrene as monomer and p-vinylbenzyl chloride as capping agent.The star-branched styrene-butadiene-styrene (S-g-SBS) copolymer with ordered polystyrene as side chains was designed and synthesized using butadiene and polystyrene macromonomer as monomers and divinyl benzene as coupling agent.The chemical constitution and microstructure of polystyrene macromonomers and S-g-SBS were characterized by proton nuclear magnetic resonance spectrometer, gel permeation chromatographer and differential scanning calorimeter, and the rheological properties of S-g-SBS were analyzed by rotational rheometer.The results showed that polystyrene macromonomers with controlled molecular weight and narrow molecular weight distribution were obtained.The content of 1,2-structure of polybutadiene in S-g-SBS could be regulated between 30% and 70%, and the lower the content of 1,2-structure, the lower the melt viscosity.For the similar molecular structural parameter, the melt viscosity of S-g-SBS was obviously lower than that of linear SBS.

[Display omitted] • A well-defined polymer containing the triphenylamine group (poly(A)) was precisely synthesized via living anionic polymerization. • Simple thermal treatment at temperature above the glass transition temperature yielded a poly(A) film resistant to the solvent used in the emissive layer. • The suitability of poly(A) as a hole-transporting layer for solution-processable OLEDs has been confirmed. In this study, we conducted anionic polymerization of N -[1,1′-biphenyl]-4-yl- N -(4′-ethenyl[1,1′-biphenyl]-4-yl)-9,9-dimethyl-9 H -fluoren-2-amine (A) incorporating a triphenylamine group as a hole-transporting unit using sec -butyllithium and potassium naphthalenide as initiators in tetrahydrofuran at −30 ℃ for 10 min. The resultant poly(A)s exhibited controlled molecular weights (M n = 20.9−126.3 kg/mol) and narrow molecular weight distributions (M w / M n ≤ 1.12). The living nature of the propagating chain end of poly(A) was confirmed by postpolymerization. Additionally, block copolymerization of A with styrene (St) and 2-vinylpyridine (2VP) was performed to assess its relative reactivity. Copolymerization resulted in the precise synthesis of well-defined block copolymers with poly(A) segments. Thermal properties of poly(A) were investigated using thermogravimetric analysis and differential scanning calorimetry. Notably, the thermal annealing of poly(A) film at 230 ℃ for 10 min made it insoluble in toluene, indicating its solvent resistance. Thus, poly(A) was used as the hole-transporting layer (HTL) in solution-processable organic light-emitting diodes (OLEDs). A comparative analysis against a reference device containing poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) revealed an enhancement in the performance of the OLED comprising thermally annealed poly(A) as the HTL. These results strongly suggest that poly(A) is a promising HTL material for solution-processable OLEDs. [ABSTRACT FROM AUTHOR]

[Display omitted] • As for styrene (S) and conjugated 1,3-dienes (e.g. 1,3-pentadiene, P) monomers, living anionic polymerization (LAP) has significant advantages in precise control of molecular weight and its distribution and precise control of microstructure and the sequence distribution. • a series of novel symmetrical triblock copolymers of different compositions with homo-polystyrene as end-blocks and strictly alternating sequence as mid-block, Poly(S)-b-Poly(S-alt-P) -b-Poly(S) (SSPS), was synthesized in cyclohexane by classical three-step sequential feeding method using n-BuLi as initiator. • Quantitative epoxidation post-polymerization functional modification was performed to obtain the novel triblock copolymer product which had a high-polarity and high-transparent thermoplastic resin with well-defined structure and quantitative degree of epoxidation (ED). Pure multi-block copolymers and deformed multi-block copolymers have unique applications in the field of high-performance thermoplastic elastomers, resins and rubber materials. For styrene (S) and conjugated 1,3-dienes (e.g. 1,3-pentadiene, P) monomers, living anionic polymerization (LAP) has significant advantages in precise control of molecular weight and its distribution and precise control of microstructure and the sequence distribution. Subsequently, the post-polymerization modification strategy including epoxidation can further expand the application field of such polymer materials. Herein, a series of novel symmetrical triblock copolymers of different compositions with homo-polystyrene as end-blocks and strictly alternating sequence as mid-block, poly(S)- b -poly(S - alt - P)- b -poly(S) (SSPS), were synthesized in cyclohexane by the classical three-step sequential feeding method using n -BuLi as initiator. The effect of the block ratio of SSPS triblock copolymer on impact strength, flexural strength and yield strength of transparent resin products was studied in detail. In addition, quantitative epoxidation post-polymerization functional modification was performed to obtain the novel triblock copolymer product which had a high-polarity and high-transparent thermoplastic resin with well-defined structure and quantitative degree of epoxidation (ED). All these novel copolymers before and after modification were characterized by 1H NMR, 13C NMR, FTIR, DSC and GPC. [ABSTRACT FROM AUTHOR]

Liquid crystalline block copolymers (LCBCPs) are promising for developing functional materials owing to an assembly of better functionalities. Taking advantage of differences in reactivity between alkynyl and vinyl over temperature during hydrosilylation, a series of LCBCPs with modular functionalization of the block copolymers (BCPs) are reported by independently and site‐selectively attaching azobenzene moieties containing alkynyl (LC1) and Si‐H (LC2) terminals into well‐designed poly(styrene)‐block‐polybutadienes (PS‐b‐PBs) and poly(4‐vinylphenyldimethylsilane)‐block‐polybutadienes (PVPDMS‐b‐PBs) produced from living anionic polymerization (LAP). By the principle of modular functionalization, it is demonstrated that mono‐functionalized (PVPDMS‐g‐LC1)‐b‐PB and PS‐b‐(PB‐g‐LC2) not only maintain independence but also have cooperative contributions to bi‐functionalized (PVPDMS‐g‐LC1)‐b‐(PB‐g‐LC2) in terms of mesomorphic performances and microphase separation, which is evident from differential scanning calorimetry (DSC) and polarized optical morphologies (POM) and identified by powder X‐ray diffractions. With the application of the new principle of modular functionalization, local‐crosslinked liquid crystalline networks (LCNs) with controlled functionality are successfully synthesized, which show well‐controlled phase behaviors over molecular compositions. [ABSTRACT FROM AUTHOR]

This article reviews the various developments of a new methodology combining the living anionic polymerization and a designed linking chemistry for the synthesis of block polymers using two, two of three, three, or four monomers with different reactivities. With this methodology, a number of well-defined triblock copolymers, triblock terpolymers, tetrablock quaterpolymers, and multiblock copolymers with alternating two segments have been successfully synthesized. The obtained polymers were all novel well-defined block polymers with unusual block sequences. More importantly, they are definitely inaccessible by the sequential polymerization using monomers with different reactivities. The monomers used in the synthesis were mainly styrene, 2-vinylpyridine, and methyl (or tert-butyl) methacrylate classified into three categories by their reactivities. In addition, 1,2-butylene oxide was used as the fourth monomer to synthesize the tetrablock quaterpolymers. There are also a number of other monomers classified into each of these categories, which can be readily replaced from the main monomers. By developing the methodology using these monomers, it becomes possible to synthesize a far more number of block polymers beyond our imagination. In practice, several synthetic feasibilities are described in each chapter. The key for this synthetic success is to suitably choose an α-phenylacrylate function used as the reaction site, capable of quantitatively linking with each of the living anionic polymers having a wide range of reactivity, which makes it possible to connect two different polymer segments difficult to access by the sequential polymerization. One more important issue is to employ the iterative linking process, which enables the successive synthesis of alternating multiblock copolymers of up to the decablock type and possibly with more blocks. Generality, versatility, and advantages of the proposed methodology have been demonstrated throughout the synthesis of the block polymers. [ABSTRACT FROM AUTHOR]

Well-controlled anionic polymerization of an initiator-functionalized monomer, p-(2,2′-diphenylethyl)styrene (DPES), was achieved for the first time. The polymerization was performed in a mixed solvent of cyclohexane and tetrahydrofuran (THF) at 40 °C with n-BuLi as initiator. When the volume ratio of cyclohexane to THF was 20, the anionic polymerization of DPES showed living polymerization characteristics, and well-defined block copolymer PDPES-b-PS was successfully synthesized. Furthermore, radical polymerization of methyl methacrylate in the presence of PDPES effectively afforded a graft copolymer composed of a polystyrene backbone and poly(methyl methacrylate) branches. The designation of analogous monomers and polymers was of great significance to synthesize a variety of sophisticated copolymer and functionalize polymer materials.

We report here a method for the preparation of amphiphilic dendrimer-like copolymers with dendritic polystyrene (PS) core and protonated poly(2-vinyl pyridine) (P2VP) or poly(methacrylic acid) (PMAA) shell. The method employed the efficient coupling reaction of anionic living polymer chains and chlorosilane. The synthesis started from a functionalized 3rd generation dendritic polystyrene, G3PS-g-SiCl, used as the precursor. The dendrimer-like copolymer of styrene and 2-vinyl pyridine, G3PS-g-P2VP, was synthesized by direct coupling of living P2VPLi to the precursor. The dendrimer-like copolymer of styrene and tert-butyl methacrylate, G3PS-g-PtBMA, was synthesized by an indirect procedure in which a living polymer containing mainly PtBMA segment was attached to the precursor. Both methods resulted in the formation of dendrimer-like copolymers with the high molecular weights (up to 8.5 × 106 Da), large molecular sizes (diameter up to 73 nm), and dense shells (number of arms up to 1300). These products, G3PS-g-P2VP and G3PS-g-PtBMA, were protonated with trifluoroacetic acid and acidic hydrolyzed, respectively. After transformation, amphiphilic dendrimer-like copolymers, G3PS-g-P2VPH+ and G3PS-g-PMAA, were obtained. Preliminary results on the solution properties of the amphiphilic products were presented. [ABSTRACT FROM AUTHOR]

"Thiol-yne" click reaction has already been widely applied in synthesis and modification of new polymer structures or novel materials due to its specific features. However, in most studies, only chain-end strategy was employed when using the di-addition feature of thiol-yne reaction, thus the in-chain di-addition strategy could endow us with a broader space to develop the synthesis of advanced polymers. Therefore, in this paper, the features of in-chain mono- and di-addition were investigated when modifying the alkyne-functionalized polymers to prepare grafted polymers via thiol-yne click reaction. The results showed that it is almost impossible to obtain the in-chain di-adducts even under excess feeding of chain-end thiol-functionalized grafts, while only the in-chain mono-adducts could be obtained efficiently. Further researches investigated that the controlled grafting could be encountered when carrying out the thiol-yne click reaction between chain-end alkyne-functionalized polystyrenes and chain-end thiol-functionalized polystyrenes under proper feedings. Therefore, the effect of steric-hindrance might be the primary reason for the alternative grafting via thiol-yne click reaction between in-chain and chain-end alkyne-functionalized polymers. [ABSTRACT FROM AUTHOR]

Microphase‐separated structures of a series of AB6 block‐graft copolymers were studied by TEM and SAXS. Ten copolymers with the same polystyrene (S) backbone and six polyisoprene (I) grafts on the average but with different graft chain lengths were carefully synthesized by living anionic polymerization, covering the range 0.21 ≤ ϕS ≤ 0.90, where ϕS denotes polystyrene compositions. From TEM observation of the AB6 block‐graft copolymers, it turns out to be clear that they show four microphase‐separated structures, S‐spheres, S‐cylinders(S‐prisms), alternative lamellae, and I‐cylinders. Among them, for example, the samples with 0.54 ≤ ϕS ≤ 0.58 shows prism structures whose cross sections of the S domains are close to hexagons, not circles, due to packing frustration of grafts. Composition dependence of morphologies of the present AB6 block‐graft copolymers reveals their phase diagram is extremely asymmetric with respect to ϕS = 0.5. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 952–960 [ABSTRACT FROM AUTHOR]

Block copolymers containing polytetrahydrofuran segments were synthesized by umpolung or propagating end of the cationic living polymer and successive anionic polymerization of methacrylates (RMAs) or radical polymerization of RMAs, acrylonitrile (AN), and styrene (St). Living polytetrahydrofuran (poly-THF) was prepared by cationic polymerization of tetrahydrofuran (THF), whose propagation end was reduced by samarium(II) iodide (SmI2). Anionic polymerizations of RMAs were conducted by addition of the monomers to the reduced poly-THF to obtain poly(THF-b-RMAs). On the other hand, the 2-bromoisobutyrate group, which can act as an initiator of radical polymerization, was introduced to the cationic propagating end of poly-THF by adding sodium 2-bromoisobutyrate. Block copolymers were synthesized by living radical polymerization of RMAs, St, or AN using the 2-bromoisobutyrate-capped poly-THF as a macroinitiator and copper(I) bromide (CuBr) as a catalyst. [ABSTRACT FROM AUTHOR]

A novel convenient dual-side initiator of lutidine dianion for anionic polymerization has been investigated in terms of their initiation and propagation kinetics. This lutidine dianion could be synthesized in quantitative yields reacting commercial products of 2,6-lutidine with sec-butyl lithium without any complex organic synthesis, and could be used effectively as the dual-side initiator to synthesize polyisoprene with various molecular weights via living anionic polymerization. In addition, this lutidine dianion can produce 50% of 1.4-microstructure contents in polyisoprene which is very important for elastomeric property of polydienes. All experimental evidences showed the living property and were consistent with quantitative yields without any side reactions when the anionic living polymerization proceeded using lutidine dianion as the initiator. [ABSTRACT FROM AUTHOR]

The specific features for the synthesis of periodic polymers with the 1,1-diphenylethylene (DPE) derivatives were investigated via living anionic copolymerization. Thus, three DPE derivatives, including dimethyl-[4-(1-phenylvinyl)phenyl]silane (DPE-SiH), 1,1-diphenylethylene (DPE) and 1-propyl-4-(1-phenylvinyl)benzene (DPE-propyl), were selected for living anionic copolymerization with styrene (St) under regulated feed ratios. Real-time in situ 1H NMR method was applied to monitor the whole chain propagation process to investigate the detail kinetics of the formation of periodic structures and corresponding sequence distribution in chain. Through the real time 1H NMR monitoring, the special phenomena were observed that kinetic curves of DPE derivatives and St showed almost coincide and the apparent kinetic parameters were nearly equal in broad feed ratios. Meanwhile, the in situ 1H NMR results indicated that a series of periodic structure, in which the DSDSS or DSS repeating patterns dominantly distributed along the chains, were deduced and the sequence structures are determined by the feed ratios and the reactivity of corresponding DPE derivatives. The glass transition temperatures (T g s) of the resultant copolymers have been tested to investigate the influence of the repeating patterns on the thermal properties. Image 1 • Periodic polymers with different repeating patterns were obtained with DPE derivatives via living anionic polymerization. • Sequence structures in periodic polymers are relate to the monomer feeding ratio and the reactivity of the DPE derivatives. • Coincided kinetic behaviors were observed when periodic structures were generated during the copolymerization. [ABSTRACT FROM AUTHOR]

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 The direct mechanistic transformation during "controlled"/living polymerizations of styrene derivatives was accomplished through anionic, cationic, and radical growing active species via terminal carbon–halogen bond. The terminal chlorination in the anionic polymerization proceeded quantitatively under an appropriate condition, which consequently produced a macroinitiator for living cationic and radical polymerizations. The transformation allowed the synthesis of novel block copolymers including gradient block copolymers composed of styrene and p‐methylstyrene. [ABSTRACT FROM AUTHOR]

Reported is an intriguing advance in living anionic polymerization (LAP) by a "locked‐unlocked" mechanism in which the living anionic species can be quantitatively locked by end‐capping with 1‐(tri‐isopropoxymethylsilylphenyl)‐1‐phenylethylene (DPE‐Si(O‐iPr)3) and can be unlocked by adding the key, sodium 2,3‐dimethylpentan‐3‐olate (NaODP). These new insights into this mechanism were carefully confirmed by designing reactions involving sequential feeding of quantitative DPE‐Si(O‐iPr)3 and traditional monomers mixed with NaODP, and subsequently characterizing the corresponding samples, taken during the feeding process, by GPC, NMR, and MALDI‐TOF‐MS techniques. The switch from the locked to unlocked state was clearly confirmed by these characterization techniques. The putative locked‐unlocked mechanism in the LAP was simulated by the Gaussian method. This intriguing mechanistic finding of LAP reactions is expected to supplement the existing knowledge and facilitate the tailoring of specific structures for these polymerizations. Locked in: An intriguing advance in living anionic polymerization (LAP) by a "locked‐unlocked" mechanism was investigated. The living anionic species can be quantitatively locked by end‐capping with 1‐(tri‐isopropoxymethylsilylphenyl)‐1‐phenylethylene (DPE‐Si(O‐iPr)3) and can be unlocked by adding the key, sodium 2,3‐dimethylpentan‐3‐olate (NaODP). [ABSTRACT FROM AUTHOR]

Poly(ethylene oxide) (PEO) was controllably grafted from styrene-b-(ethylene-co-propylene)-b-styrene (SEPS) backbones by combining lithiation of styrenic units and living monomer-activated anionic ring-opening polymerization of ethylene oxide (EO) monomers with the aid of co-initiators triisobutyl aluminum. The as-synthesized SEPS-g-PEO copolymers were characterized by SEC, 1H-NMR, FTIR, SAXS, AFM and DSC. When the branch length is relatively small, increase of PEO fraction leads to the increase of the correlation length between neighboring hard domains, but the degree of correlation reduces. When the branch length is relatively large, the phase-separated structures become random both in terms of size and spatial correlation, and macro-phase separated structures appear. The crystallization behavior of the PEO branches can be effectively inhibited in SEPS-g-PEO, so no significant crystallization takes place until the fraction of PEO branches is 20.1 wt%, which greatly promotes the rapid delivery of hydrophilic drugs in the hot-melting pressuresensitive adhesives (HMPSAs) based on SEPS-g-PEO. Their cumulative release amount of a model drug could achieve 80%, more than twice the value in the HMPSAs based on linear PEO-containing styrenic block copolymers. [ABSTRACT FROM AUTHOR]

Three amine-functionalized 1,1-diphenylethylene (DPE) derivatives (DPE-(NMe 2 ) 2 , DPE-NMe 2 and DPE-SiH/NMe 2 ) were used to study the end-capping reactions of poly(styryl)lithium (PS-Li) for investigating the effect on end-capping of electron-donating groups in DPE structures. In situ 1 H NMR was used to measure the kinetic parameters of end-capping reactions. When the DPE derivative was held constant in the PS-Li capping reaction, the kinetic parameter (k SD ) did not change with the variance of either concentration or degree of polymerization of PS-Li. Additionally, the k SD value changed dramatically when various electronic properties of the DPE derivative substituents were modified. Electron-withdrawing groups accelerated the end-capping reaction, while electron-donating groups decelerated it. The k SD experimental values of DPE-(NMe 2 ) 2 , DPE-NMe 2 and DPE-SiH/NMe 2 were found to be 0.155 × 10 −3 , 1.26 × 10 −3 , and 6.24 × 10 −3 L 1/2  mol −1/2 s −1 , respectively. An intuitive model was established to simulate the precision of the sequence-controlled copolymerization with DPE derivatives based on investigations of end-capping kinetics. The model depicts the degree of fictitious styrene propagation for the chain insertion of one DPE derivative unit. The fictitious degrees of polymerization of styrene (FDPs) for DPE-NMe 2 and DPE-SiH/NMe 2 were calculated to be 37 and 13, respectively, suggesting that using DPE derivatives containing an electron-withdrawing group in the synthesis of sequence-controlled polymers might lead to a more precise structure. [ABSTRACT FROM AUTHOR]

The living anionic polymerization of 1,4-divinylbenzene and its derivatives was reviewed. With the use of a specially-designed initiator system prepared from oligo(α-methylstyryl) lithium and potassium tert -butoxide, the living anionic polymerization of 1,4-divinylbenzene was successfully realized for the first time. During this polymerization, one of the two vinyl groups was selectively polymerized in a living manner, while the other vinyl group remained completely intact in the main chain. Soluble linear polymers with well-controlled molecular weights up to 60.5 kg mol −1 and narrow molecular weight distributions ( M w / M n  < 1.05) were obtained under such conditions. The success of the living polymerization may possibly result from the formation of the less reactive by less dissociation and bulkier anionic species and the reactivity differentiation between the two vinyl groups before and after the polymerization. It was also demonstrated that a variety of divinylbenzene derivatives, such as 1,2-divinylbenzene, 1,4-divinylnaphthalene, 2-methoxy-1,4-divinylbenzene, 4-methoxy-1,2-divinylbenzene, 4-methoxy-1,3-divinylbenzene, 1,4-diisopropenylbenzene, 4-(α-methylethenyl)styrene, 4-(α-ethylethenyl)styrene, 4-(α-butylethenyl)styrene, 4-(α-isopropylethenyl)styrene, and 4-(α- tert -butylethenyl)styrene, underwent the living anionic polymerization with the same designed initiator system under similar conditions. New well-defined block polymers and star -branched polymers with reactive poly(1,4-divinylbenzene) segment(s) could be successfully synthesized by using the living anionic poly(1,4-divinylbenzene). Throughout the block copolymerization study, it was found that the reactivities of 1,4-divinylbenzene and the generated chain-end anion were comparable to those of 2-vinylpyridine. Although 1,4-divinylbenzene is a styrene derivative, it was higher in monomer reactivity than styrene, but its chain-end anion was less reactive than that generated from styrene. [ABSTRACT FROM AUTHOR]

Thermoplastic elastomers (TPEs) have been widely studied because of their recyclability, good processibility, low production cost, and unique performance. The building of graft-type architectures can greatly improve mechanical properties of TPEs. This review focuses on the advances in different approaches to synthesize multigraft copolymer TPEs. Anionic polymerization techniques allow for the synthesis of well-defined macromolecular structures and compositions, with great control over the molecular weight, polydispersity, branch spacing, number of branch points, and branch point functionality. Progress in emulsion polymerization offers potential approaches to commercialize these types of materials with low production cost via simple operations. Moreover, the use of multigraft architectures provides a solution to the limited elongational properties of all-acrylic TPEs, which can greatly expand their potential application range. The combination of different polymerization techniques, the introduction of new chemical compositions, and the incorporation of sustainable sources are expected to be further investigated in this area in coming years. [ABSTRACT FROM AUTHOR]

Frontispiece: Merging Styrene and Diene Structures to a Cyclic Diene: Anionic Polymerization of 1-Vinylcyclohexene (VCH) Keywords: 1,3-Dienes; Copolymerization Kinetics; Living Anionic Polymerization; Polyisoprene; Polystyrene EN 1,3-Dienes Copolymerization Kinetics Living Anionic Polymerization Polyisoprene Polystyrene 1 1 1 07/05/23 20230710 NES 230710 B Polymers b . 1,3-Dienes, Copolymerization Kinetics, Living Anionic Polymerization, Polyisoprene, Polystyrene. [Extracted from the article]

Keywords: Copolymerization Kinetics; 1,3-Dienes; Living Anionic Polymerization; Polyisoprene; Polystyrene DE Copolymerization Kinetics 1,3-Dienes Living Anionic Polymerization Polyisoprene Polystyrene 1 1 1 07/05/23 20230710 NES 230710 B Polymers b . The obtained polymers have well-controlled molecular weights, determined by the molar ratio of monomer and initiator, with narrow molecular weight distributions. In their Communication (e202302907), Holger Frey et al. report the first anionic polymerization of 1-vinylcyclohexene. [Extracted from the article]

This article reviews the development of a novel all-around iterative methodology combining living anionic polymerization with specially designed linking chemistry for macromolecular architecture syntheses. The methodology is designed in such a way that the same reaction site is always regenerated after the polymer chain is introduced in each reaction sequence, and this "polymer chain introduction and regeneration of the same reaction site" sequence is repeatable. Accordingly, the polymer chain can be successively and, in principle, limitlessly introduced to construct macromolecular architectures. With this iterative methodology, a variety of synthetically difficult macromolecular architectures, i.e., multicomponent µ-star polymers, high generation dendrimer-like hyperbranched polymers, exactly defined graft polymers, and multiblock polymers having more than three blocks, were successfully synthesized. [ABSTRACT FROM AUTHOR]

By combining living anionic polymerization and the highly efficient Ugi four-component reaction (Ugi-4CR), in-chain, multicomponent, functionalized polymers are facilely synthesized with efficient conversation and abundant functionality. l-[4-[ N, N-Bis(trimethylsilyl)-amino]phenyl]-l-phenylethylene, which is redefined as Ugi-DPE, is anionically copolymerized to synthesize the well-defined in-chain, multi-amino functionalized polystyrene (P(St/DPE-NH2)), the backbone for the Ugi-4CR, via hydrolysis of the copolymerization (P(St/Ugi-DPE)). Subsequently, several functionalized components are facilely clicked onto P(St/DPE-NH2) to investigate the model reactions of the in-chain, multicomponent functionalization via the Ugi-4CR. In contrast to conventional postpolymerization modifications, this approach proceeds under mild reaction conditions without the use of a catalyst and meanwhile an efficient conversation is obtained. Finally, the modified experimental results investigated in this research show the promising potential of the combination of well-defined amino functionalized polymers and Ugi-4CR in the field of multicomponent, functionalized postpolymerization modification. [ABSTRACT FROM AUTHOR]