Polymerization Of Butadiene Research Articles

High Molecular Weight Semicrystalline Substituted Polycyclohexene From Alternating Copolymerization of Butadiene and Methacrylate and Its Ambient Depolymerization.

Cyclohexene cannot be polymerized via ring-opening polymerization under any conditions due to its lack of ring strain. A hypothetical polycyclohexene would therefore have a strong thermodynamic driving force to depolymerize to monomer if a metathesis catalyst were provided while otherwise having thermal and hydrolytic stability under normal conditions because of its hydrocarbon backbone. We envisioned access to this otherwise unattainable family of polymers via the alternating polymerization of a diene and an alkene. Ethyl aluminum chloride was found to promote highly alternating polymerization of butadiene and methacrylate when radically initiated at room temperature, resulting in formal polycyclohexene structures. Ultrahigh molecular weight (up to 1750 kDa) polymers can be synthesized at the decagram scale in high monomer conversions. The resulting presumably atactic copolymers exhibited semicrystallinity, leading to high toughness. In the presence of a small amount of the Grubbs catalyst, the generated polycyclohexene can be fully depolymerized at ambient temperatures into pure constituent cyclohexene. The strategy of using orthogonal chemistry for the polymerization and depolymerization processes allows access to polymer structures with subambient ceiling temperatures without using ultralow temperature synthesis or relying on the monomer-polymer equilibrium.

Correction to “Calcium–Lithium Systems as Innovative Bimetallic Initiators for the Anionic Polymerization of Butadiene: Toward Control and High 1,4-Trans Microstructure”

Correction to “Calcium–Lithium Systems as Innovative Bimetallic Initiators for the Anionic Polymerization of Butadiene: Toward Control and High 1,4-Trans Microstructure”

Novel polybutadiene rubber with long cis-1,4 and syndiotactic vinyl segments (CVBR) for high performance sidewall of all-steel giant off-the-road tire

The novel polybutadiene rubbers (CVBR) carrying 88–97% of long cis-1,4 polybutadiene segments (cis-PB, cis-1,4 content >98.3%) and 3–12% of long syndiotactic1,2-polybutadiene segments (sPB, 1,2 content >87.0%) could be successfully synthesized via in-situ coordination polymerizations of butadiene in hexanes in our lab and also be scaled up via continuous polymerization process in pilot (scale: 200 t/a). The natural rubber (NR)-based compound formulations containing different contents of CVBR, and carbon black (CB) fillers were developed and the optimized NR/CVBR/CB vulcanizates with 40% of CVBR were manufactured for the sidewall of all-steel giant off-the-road tire. The storage modulus of NR/CVBR/CB compounds and the elastic modulus, tensile strength and tear strength of NR/CVBR/CB vulcanizates could be remarkably increased by increasing CVBR content. The crack generation and growth could be effectively restricted due to both the fast relaxation, the rigid polymer-filler interface and synergistic effect of high cis-polybutadiene and crystalline 1,2-polybutadiene particles on the strain-induced crystallization behaviors of rubber matrix. The heat build-up of NR/CVBR/CB vulcanizates could be greatly reduced by introduction of cis-PB segments in CVBR for the easy mobility and low hysteresis of macromolecular chains. The NR/CVBR/CB vulcanizates with high strength and elastic modulus, good flex fatigue crack resistance and low heat build-up would meet the requirement for high performance sidewall in manufacturing giant all-steel off-the-road tires.

Calcium–Lithium Systems as Innovative Bimetallic Initiators for the Anionic Polymerization of Butadiene: Toward Control and High 1,4-trans Microstructure

Calcium–Lithium Systems as Innovative Bimetallic Initiators for the Anionic Polymerization of Butadiene: Toward Control and High 1,4-trans Microstructure

Study on Catalytic Behavior of Iron-based Catalyst with IITP as Electron Donor in the Polymerization of Butadiene

Study on Catalytic Behavior of Iron-based Catalyst with IITP as Electron Donor in the Polymerization of Butadiene

Soft-sensor estimation via parameter fitting and dynamic optimization in an experimental batch butadiene homopolymerization reactor

In this work, we address modeling and experimental tasks to develop an industrial process for the anionic polymerization of butadiene, which is a key compound used in the production of high-performance tires. The aim of this study was to determine the processing conditions that lead to the efficient manufacturing of polybutadiene. Accordingly, an experimental polymer reaction facility was constructed to record both butadiene conversion and temperature profiles. A first-principles dynamic mathematical model was developed to track the measurement variables as best as possible. To improve the tracking of recorded variables, some process variables were deployed as manipulated variables. Because good experimental tracking was not acceptable, we used the soft-sensor approach to estimate some additional degrees of freedom. The estimation task was performed by describing the problem as a dynamic optimization problem. The results clearly show that the optimization and control tasks of butadiene polymerization reaction facilities are demanding and require good experimental information to develop reliable mathematical models that can be leveraged to speed up the development of such industrial polymerization systems.

Investigating The Kinetics of Anionic Polymerization of Butadiene in Presence of 1,2‐diethoxypropane Using Online Near‐Infrared Spectroscopy

AbstractOnline near‐infrared spectroscopy technique is employed to investigate the kinetics of the anionic polymerization of butadiene with n‐butyllithium initiator in the presence of the microstructure modifier 1,2‐diethoxypropane (DEP) in cyclohexane solvent. A phenomenological kinetic model is developed to describe the anionic polymerization process in the presence of DEP, and its influence on the microstructure of polybutadiene under different conditions is determined.

Polymerization of isoprene and butadiene with unparalleled stereoselectivity catalysed by rare-earth metal cationic species bearing a novel tridentate ligand

Phenylthiol-functionalized rare-earth metal cationic species showed unparalleled stereoselectivity in the polymerization of isoprene and butadiene to respectively produce cis-1,4-polyisoprene and trans-1,4-polybutadiene.

Stereoselectivity in Butadiene Polymerization Promoted by Using Ziegler–Natta Catalysts Based on (Anilidomethyl)pyridine Group (IV) Complexes

The stereoselective polymerization of conjugated dienes promoted by using transition metal complexes has attracted much interest in both industrial and academic environments for the relevance of polydienes as synthetic rubbers and for the challenging reaction mechanisms. Among the different transition metal complexes, those based on group IV have been demonstrated to be versatile and efficient catalysts. Titanium complexes are generally more active than zirconium complexes. A rare exception to this trend is represented by a series of Zr(IV) complexes supported by (anilidomethyl)pyridine ligands that, after activation by using Al(iBu2H)/MAO, were found to be highly active affording exclusively cis-1,4-polybutadiene. To rationalize this unexpected trend and to obtain more insights into the parameters that control the reactivity of group IV complexes, a theoretical investigation of the entire polymerization mechanism, employing density functional methods, was undertaken. In the framework of the widely accepted polymerization scheme, the different intermediates featuring h4 (both cis and trans) coordination of the monomer and h1 or h3 (syn or anti)allyl coordination of the growing chain were scrutinized. Subsequently, the effects of the metal center on the free-energy profiles of the elementary steps involved in the reaction were examined. The results presented herein aim to achieve a better knowledge of the influence of the metal on the polymerization rates and on the stereoselectivity of the reaction.

Coordinative Chain Transfer Polymerization of Butadiene Using Nickel(II) Allyl Systems: A Straightforward Route to Branched Polybutadiene

Coordinative Chain Transfer Polymerization of Butadiene Using Nickel(II) Allyl Systems: A Straightforward Route to Branched Polybutadiene

Synthesis of block copolymer with cis-1,4-polybutadiene and isotactic-rich polystyrene using α-diimine nickel catalysts.

A series of styrene-butadiene di-block copolymers with high cis-1,4 unit content (greater than 92%) polybutadiene (PB) and isotactic-rich polystyrene (PS) (mmmm > 65%) was synthesized using α-diimine nickel catalysts (Ni-diimine). Four different Ni-diimine catalysts were synthesized via a complexing reaction between nickel (II) naphthenate and laboratory-made α-diimine ligands L1, L2, L3 and L4, which have different steric volume structures. The results indicate that the Ni-diimine catalyst prepared using the L4 ligand with a higher steric volume can effectively initiate the block polymerization of butadiene and styrene, and the resulting polymer has distinguished cis-1,4 structure unit PB and high isotactic-selective PS block. Differential scanning calorimetry and electrochemical performance tests show that these block copolymers with cis-1,4-regulated and isotactic-selective polymerization have advantages in terms of high-temperature and low-temperature resistance as well as corrosion resistance. Therefore, these copolymers are expected to be widely used in some harsh industrial environments.

Polymerization of isoprene, myrcene, and butadiene catalyzed by cobalt complexes supported with 2‐acetyl‐6‐iminopyridine ligand

Cobalt complexes carrying 2‐acetyl‐6‐iminopyridine ligand are synthesized and characterized. Single‐crystal X‐ray diffraction reveals the cobalt ion is chelated with two nitrogen atoms and an acetyl oxygen atom additionally. A significant prolonged Co–O distance (2.3960(57) Å) is found, indicative of a labile character. Activated by diethylchloroaluminum, all complexes show high conversion rates for isoprene and myrcene polymerizations, affording cis‐1,4/3,4 regulated 1,3‐diene polymers. The polymerization of butadiene, interestingly, gives predominant cis‐1,4 selectivity (>99.2%) with moderate activity. The substituent at ortho‐position of arylimine plays a minor role in controlling activity and selectivity as well as the molecular weight of the resultant polymers. The properties of resultant poly(1,3‐diene)s are stable even in a wide range of operational conditions, such as [Al]/[Co] varied from 20 to 600, temperature spanning from 0°C to 60°C, and monomer–catalyst ratio from 1000 to 4000. These additional benefits of minimum fluctuation in catalytic performances may be suitable for industrial polymerization process.

Cationic polymerization of butadiene with isomerization of the initiator structure

Cationic polymerization of butadiene with isomerization of the initiator structure

Threading-the-Needle: Compatibilization of HDPE/iPP blends with butadiene-derived polyolefin block copolymers

Management of the plastic industry is a momentous challenge, one that pits enormous societal benefits against an accumulating reservoir of nearly indestructible waste. A promising strategy for recycling polyethylene (PE) and isotactic polypropylene (iPP), constituting roughly half the plastic produced annually worldwide, is melt blending for reformulation into useful products. Unfortunately, such blends are generally brittle and useless due to phase separation and mechanically weak domain interfaces. Recent studies have shown that addition of small amounts of semicrystalline PE-iPP block copolymers (ca. 1 wt%) to mixtures of these polyolefins results in ductility comparable to the pure materials. However, current methods for producing such additives rely on expensive reagents, prohibitively impacting the cost of recycling these inexpensive commodity plastics. Here, we describe an alternative strategy that exploits anionic polymerization of butadiene into block copolymers, with subsequent catalytic hydrogenation, yielding E and X blocks that are individually melt miscible with PE and iPP, where E and X are poly(ethylene-ran-ethylethylene) random copolymers with 6 wt% and 90 wt% ethylethylene repeat units, respectively. Cooling melt blended mixtures of PE and iPP containing 1 wt% of the triblock copolymer EXE of appropriate molecular weight, results in mechanical properties competitive with the component plastics. Blend toughness is obtained through interfacial topological entanglements of the amorphous X polymer and semicrystalline iPP, along with anchoring of the E blocks through cocrystallization with the PE homopolymer. Significantly, EXE can be inexpensively produced using currently practiced industrial scale polymerization methods, offering a practical approach to recycling the world's top two plastics.

Preparation and properties of high vinyl polybutadiene/sepiolite nanocomposites using a sepiolite immobilized Mo‐based catalyst

AbstractThe preparation of polymer/nanoclay nanocomposite has received much attention in recent years from both academic researchers and industry. The addition of nanoclay in polymer matrix could prepare material with improved performance and reduced cost. However, nanocaly is easy to agglomerate resulting in poor dispersion in the matrix. In this work, we proposed the immobilized catalyst prepared by coordination between molybdenum pentachloride (MoCl5) and hydroxyl groups on the nano sepiolite. The obtained sepiolite immobilized catalyst was used for the in situ polymerization of butadiene. The butadiene monomers were diffused into the tiny holes and channels of the sepiolite and sepiolite dispersed uniformly by the effect of in situ polymerization. The immobilization of sepiolite improves the dispersity of MoCl5 during polymerization and further enhances the activity of the catalyst. The coordination between sepiolite and MoCl5 results in a slight drop in vinyl content, and the molecular weight distribution remain unchanged. The flame retardant property of the nanocomposite was further investigated, and the result shows that the addition of sepiolite could increase the Oxygen index. This novel composite with well‐dispersed sepiolite and high content of vinyl can be further applied to flame‐retardant elastic materials.

Polymerization of butadiene and isoprene using α-diimine cobalt catalysts bearing electron donor at the N-aryl of imine

Cobalt dibromide supported by α-diimine ligand ortho-positioned with sulfur and oxygen donor are synthesized and characterized. Single X-ray diffraction result shown the oxygen donor is connected with the metal center in complex Co4, resulting in a triangle bipyramidal configuration. With AlEt2Cl as an activator, the formed catalysts are able to efficiently catalyze butadiene polymerization following in an essential cis-1,4 chemoselectivity at 1/2000–1/6000 catalyst feeding. These catalysts are more active and robust for isoprene polymerization under identical conditions, affording polyisoprene rich in cis-1,4 fraction randomly incorporated with 3,4 units. The number average molecular weights (Mns) of the formed polymers are determined to be 1.1–7.8 × 105, higher than those found for polybutadiene (0.4–9.3 × 104). The O-Me donor in the N-Aryl impacts positively on the activity and the molecular weight of the resultant polymer. The catalysts show a stable chemoselectivity despite the activator and catalyst feeding, applied temperature, even the catalyst structure are varied.

Cationic Half-Sandwich Tetrahydrofluorenyl Rare-Earth Metal Complexes as Stable Single-Site Catalysts for (Co)Polymerization of Styrene and Butadiene.

As indenyl-derivates, the tetrahydrofluorenyl ligands had an expanded "wingspan" with considerable steric hindrance. In this text, the rare-earth metal complexes bearing tetrahydrofluorenyl ligands have been synthesized and fully characterized by NMR (1H and 13C) and X-ray diffraction analyses. Upon the activation by [Ph3C][B(C6F5)4], all the scandium complexes exhibited excellent catalytic activity for highly syndioselective polymerization of styrene with a narrow molecular weight distribution (Mw/Mn < 2.0), suggesting the beneficial influence of tetrahydrofluorenyl ligands in stabilizing the single-site active species during the polymerization. Moreover, the scandium-based catalytic systems also promoted the 1,4-regular polymerization of butadiene and its copolymerization with styrene, affording diblock copolymers featuring a highly syndiotactic polystyrene block and a 1,4-specific PBD block. The kinetics investigation revealed the huge gap in TMS-Sc-catalyzed polymerization reactivity ratios (rBD/rSt > 300) between butadiene and styrene, and this further proved the block structure of styrene-butadiene copolymers. The morphology and mechanical property of the selected diblock copolymer were, respectively, investigated by atomic force microscopy and stress-strain experiments.

Popcorn Polymers in Butadiene Extraction Units

Several aspects disturb operation of industrial facilities which can cause severe impact on their efficiency and productivity. In some cases, the impact can expose industrial facilities to serious safety concerns. Therefore, Industrial facilities should always plan to invest in reliability and sustainability of their daily operation. Polymerization is one of the unavoidable risks that can be unpredictable and cause several issues to operating facilities. On the other hand, effective proactive plans can be addressed to minimize and eliminate polymerization risks. This article provides introductory information about polymerization of butadiene “Popcorn polymers”, formation mechanism, associated hazard, control and mitigation methodologies.

Dichloro(2,2′-bipyridine)copper/MAO: An Active and Stereospecific Catalyst for 1,3-Diene Polymerization

Dichloro(2,2'-bipyridine)copper was synthesized by reacting copper dichloride with bypyridine, and its behavior, in combination with methylaluminoxane (MAO), in the polymerization of butadiene, isoprene, 2,3-dimethyl-1,3 butadiene, and 3-methyl-1,3-pentadiene was examined. The purpose of this study is to find catalytic systems that are more sustainable than those currently used for the polymerization of butadiene and isoprene (e.g., Co and Ni), but that are comparable in terms of catalytic activity and selectivity. Predominantly, syndiotactic 1,2 polybutadiene, crystalline syndiotactic 3,4 polyisoprene, crystalline syndiotactic 1,2 poly(3-methyl-1,3-pentadiene), and crystalline cis-1,4 poly(2,3-dimethyl-1,3-butadiene) were obtained in a manner similar to that observed with the analogous iron complex. As far as we know, the investigated catalytic system represents the first example of a copper-based catalyst in the field of stereospecific polymerization. Given the great availability of copper, its extremely low toxicity (and therefore high sustainability), and the similarity of its behavior to that of iron, the result obtained seems to us of considerable interest and worthy of further investigation.

Synthesis of Low Molecular Weight Butadiene Polymers Using Cationic Catalytic Systems Based on Diethylaluminium Chloride

Сationic polymerization of butadiene with the catalytic systems based on diethylaluminium chloride (AlEt2Cl) in combination with tertiary alkyl halides (AH), such as tert-butyl chloride, tert-butyl bromide and 2-chloro-2-methylbutane, is an effective method for obtaining fully soluble butadiene polymers at a industrially relevant temperature of 20°C. It is shown that, regardless of the nature of AH in the catalytic system, with an increase in the duration of the polymerization process of butadiene, the values of the weight-average molecular weight and polydispersity of the polymers significantly increase with the simultaneous decrease of polybutadiene unsaturation, which is associated with the transfer reaction of the growing chain to the polymer double bond during polymerization. Using the 13C NMR spectroscopy method, it was found that polybutadiene macromolecules synthesized on the AlEt2Cl–tert-butyl chloride catalytic system consist mainly of 1,4-trans units, contain two types of initial tert-butyl units and two types of end chlorine-containing units formed as a result of the transfer reaction of the growing chain to tert-butyl chloride. Based on the data of 13C NMR spectra of polybutadiene, a method for calculating the conversion of butadiene during polymerization has been developed, and a mechanism of the process of cationic butadiene polymerization has been proposed. It is shown that the synthesized “cationic” polybutadiene is characterized by high film-forming properties and can be a promising component in the production of paint and varnish materials.