Syndiotactic 1,2-polybutadiene, thermoplastic

A New Thermoplastic Syndiotactic 1,2-Polybutadiene. I. Production, Fundamental Properties, and Processing... 

A new thermoplastic syndiotactic 1, 2-polybutadiene (1, 2-PBD) has been developed by Japan Synthetic Rubber Co., Ltd.(JSR). 

As regards high Irons- 1,4-poly butadiene, it has a few applications, especially as a blend with natural rubber. Syndiotactic 1,2-polybutadiene is a unique material that combines the properties of plastic and rubber. These properties lead to applications both as a thermoplastic resin and as a rubber. As regards isotactic 1,2-polybutadiene, one may note that its properties have not excited sufficient interest for commercial development. 

JSR Corp. Polybutadiene 1,2 Butadiene Syndiotactic polybtadiene 1-2 and curable thermoplastic elastomer NA NA... 

Polystyrene (PS) in its atactic and syndiotactic forms is a brittle thermoplastic, even in an orientated state [4]. To improve the toughness of aPS, impact modification has been practised for a long time, either by polymerizing the styrene in the presence of a polybutadiene rubber leading to high-impact polystyrene, commonly called HIPS, or by blending the polystyrene with multi-block copolymers, mainly of the styrene-butadiene-styrene (S-B-S) type. 

PROPERTIES OF SPECIAL INTEREST Syndiotactic 1,2-polybutadiene is a reactive thermoplastic resin, which has characteristics of both a thermoplastic and an elastomer. 

Definition Thermoplastic consistg. of 50-65% syndiotactic polybutadiene with > 90% of the monomers linked at their 1,2-positions polymer is partially cryst., but transparent film has high gas permeability, high tear/puncture resist. 

Polybutadiene-type resins n. Unsaturated, thermosetting hydrocarbons cured by a peroxide-catalyzed, vinyl-type polymerization reaction, or by sodium-catalyzed polymerization of butadiene or blends of butadiene and styrene. Liquid systems, curable in the presence of monomers, are used for casting, encapsulation, and potting of electrical components, and in making laminates. Molding compounds, often containing fillers and modified with other resins or rubbers, may be compression or transfer molded. Syndiotactic 1,2-butadiene, introduced in 1974 in Japan, is thermoplastic, with semicrystalline nature, with good transparency and flexibility without plasticization. In the presence of a photosensitizer such as p,p -tetramethyl... 

Considering only a single repeat unit the 1,2 and 3,4 structures are identical and both polymers may be considered as 1,2-polybutadienes. However, as with polypropylene, polyvinyl chloride, polystyrene and many other thermoplastics, 1,2-polybutadiene possesses an asymmetric carbon atom so that both isotactic and syndiotactic stereoregular forms as well as the stereo-irregular atactic form are possible. 

The commercial polydienes are elastomers. Q s-1,4 polybutadiene has a Tg of -100 °C and has a crystalline melting point of less than 0 °C. Q s-1,4 polyisoprene has a Tg of -70 °C and has a crystalline melting point of 35 C. Both polymers crystallize rather slowly. Trans-1,4 polybutadiene and polyisoprenes are crystalline thermoplastics at room temperature. They are not, however, used commercially because of their poor aging characteristics relative to polyolefins. This is associated with the double bonds in their backbones. Polybutadienes with high atactic 1,2-contents have been widely used in the tire industry. Their Tg is about -15 °C. Isotactic and syndiotactic 1,2-polybutadienes are high melting crystalline thermoplastics, but age poorly compared to polyolefins. The 1,2-polybutadienes have been used as packaging for additives in the rubber industry. 

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