Highly crystalline syndiotactic 1,2‐polybutadiene (s‐PB) having melting point (mp) up to 216°C was obtained by using a Co(acac)3‐AIEt3‐CS2 catalyst. The polymer with mp 208°C was found to have 99.7% 1,2 content and 99.6% syndiotacticity by 1H and 13C‐NMR measurements. The s‐PB can be molded by addition of a stabilizer such as 2,6‐di‐t‐butyl‐4‐hydroxymethylphenol into fiber, film, and various shaped articles. The physical properties presented in the present article include stress‐strain and dynamic mechanical behavior. The highly crystalline syndiotactic 1,2‐polybutadiene was applied to a carbon fiber and UBEPOL VCR (cis‐1,4‐polybutadiene reinforced by fibrous syndiotactic 1,2‐polybutadiene).

SynopsisButadiene is polymerized by cobalt compound-organoaluminum-CSz catalysts to give highly crystalline syndiotactic 1,2-polybutadiene (s-PB) having melting point up to 216OC. An aluminum-free catalyst, CO(C4H6)(C8H13)-CS2, is also effective. Syndiotactic polymerization with C O ( C~H~) ( C~H~& C S~ is not interrupted by the addition of protic substances such as water and alcohol, but is influenced by donor or acceptor substances. The donor molecule, e.g., dimethylsulfoxide or dimethylformamide, decreases the stereoregularity, i.e., syndiotacticity and 1,2 content. An acceptor molecule of organoaluminum with appropriate acidity such as AlEt3-AlEtzCl or tetraethylaluminoxane increases the molecular weight, stereoregularity, and yield of the polymer. In the presence of CSz a mixture of cis-PB and s-PB was obtained by using Co(octoate)z-AlEtzCl-HzO, with molar ratio H20/Co less than unity. In the case of HzO/Co > 1, only cis-PB was obtained. By the addition of donor substances such as ester, ether, nitrile, and U t 3 , s-PB was obtained even when H20/Co > 1. The amount and ratio of cis-PB and s-PB are dependent upon the nature and amount of the additives. [43& = [7]gg&,, = 8.18 x 1 0 -5~~o . w a Polymerization conditions: benzene 860 mL, butadiene 85 g, at 4OoC with HzO (variable)-AlEta (3.0 mmol)-Co(acac)3 (0.045 mmol)-CSz (0.13 mmol) as the catalyst.

SynopsisThe 'Hand '3C-NMR spectra of highly crystalline syndiotactic 1,2-polybutadiene (s-PB) are discussed in order to clarify the mechanism of butadiene polymerization with cobalt compoundorganoaluminum-C& catalysts. Cis opening of the double bonds in the syndiotactic polymerization is affirmed by the study of the copolymer from perdeuteriobutadiene and cis,cis-l,4-dideuteriobutadiene. S-PB (mp 21OOC) has 99.7% 1,2 units, 0.3% isolated ck-l,4 units, and 99.6% syndiotacticity.Polymer ends (2-methyl-3-butenyl group and conjugated diene structure) are also determined. The differences in free energy of activation between 1,2 and ck-l,4 propagation and between syndiotactic and isotactic propagation are 14.0 and 9.6 kcal/mol, respectively, for Co(acac)3-AlEt3-AlEt2Cl-CS2, and 6.7 and 5.7 kcal/mol, respectively, for the aluminum-free CO(C&)(C&~)-CS~ system. The conformation of s-PB in o-dichlorobenzene at 150°C is described by the sequence (tt)l.fj(gg)(tt).

SynopsisA mechanism is proposed for the polymerization of syndiotactic 1,2-polybutadiene (s-PB) with soluble cobalt-organoaluminum-CS2. The proposed active species have structures which consist of side-on coordination of CS2 to cobalt, anti-r-ally1 growing end, cisoid bidentate coordination of butadiene, and activation by complex formation with organoaluminum at the nonbonded sulfur of the coordinated CS2. This proposal is based on findings for the aluminum-free catalyst CO(C.&)(C&I~&CS~. It is tentatively interpreted that syndiotactic 1,2 polymerization proceeds under the influence of the side-on coordinated CS2, by which the reactivity between the terminal carbons of butadiene and the C3 of the s-ally1 end is enhanced.

A complex of poly(ethylene oxide)-grafted poly(methyl)-methacrylate (PEO-PMMA) with a lithium salt has been examined as a solid electrolyte of an ambient-temperature rechargeable lithium battery. The electrolyte film was prepared by radical polymerization of PEO-grafted methacrylate which contained a lithium salt dissolved in poly(ethylene glycol) dimethyl ether. The resulting composite had a high conductivity of 10 -4 S cm -~ at room temperature. The rate of charge transfer at the lithium electrode/polymeric electrolyte interface was high, and the ion transfer in the bulk electrolyte was rate-determining at high cathodic polarization. The coulombic efficiency of lithium during the charge-discharge cycle depended on the cycling current density. The average efficiency reached 88% at 50 ~A cm -2 cycling when an A1 plate was used as a substrate.Rechargeable lithium (Li) batteries using so-called polymeric solid electrolytes such as poly(ethylene oxide) (PEO)-based polymer complexes with Li salts have been fabricated by way of trial and error (1-4). This type of battery can have an ultra-thin form and high energy density. Also, the use of a polymeric solid electrolyte will give high reliability to the battery without leakage of the electrolyte during long-term storage. Therefore, much interest has been taken in the charge-discharge behavior of cells with polymeric solid electrolytes. On the other hand, some disadvantages are also anticipated (5), e.g., relatively low conductivity of the polymeric electrolyte at ambient temperature, and poor electrical contact at the electrode/ electrolyte interface due to the volumetric change of the electrode material, especially the positive electrode, during the charge-discharge cycle.The polymer matrices so far considered are mainly PEO, poly(propylene oxide) (PPO), and related polymers. There have been many publications regarding the compositions of polymers. There have been many publications regarding the compositions of the polymer matrix-electrolytic salt systems and the ionic conductance of the resulting complexes (6). However, only a few research groups have studied the electrochemical processes at the solid electrode(s)/polymeric electrolyte interface (7-13). Despite the technical difficulty of the experimental work, it is of much importance to understand the interfacial properties of the solid electrode/polymeric electrolyte system in order to develop a high-performance rechargeable battery for practical use.We have previously reported the synthesis of a new polymeric electrolyte (Fig. 1) composed of PEO-grafted poly-(methylmethacrylate) (PEO-PMMA) with a Li salt, and showed its high ionic conductivity at room temperature (~ = -10 -4 S cm -1 at 30~ (14). The polymer matrix was PMMA with flexible side chains of PEO groups, which are effective for the transport of Li + in the matrix. Analogous concepts for designing the polymer matrix have been presented by Bannister et al. (15), and Tada and Kawahara (16). At this point Scrosati and co-workers (12, 13) have demonstrated th...