Polybutadienes, low-moLecular weight

Low molecular weight polybutadienes with terminal pyridine groups, like their hydrogen terminated counterparts, are mobile liquids. However, when quaternized in bulk with benzyl bromide (equation 3) they are transformed into solid materials. This... 

Low molecular weight polybutadienes of various mixed microstructures are prepared281 commercially via an anionic chain transfer process. These polymerizations use toluene as the solvent and transfer agent and lithium as the counter ion. The transfer reactions is promoted by the use of diamines, e.g., tetramethylethylene-diamine, or potassium t-butoxide. The preparation, modification, and applications of these materials has been described by Luxton281). 

Argon and coworkers have recently shown that low molecular weight polybutadiene may cause profile crazing in polystyrene by local plasticization. Since Argon and Cohen review this craze phenomenon in their contribution to this volume (Chapter VII) it will not be considered in this paper. 

Fig. 19a-d. Morphologies of four compliant particles in PS matrix a) KRO-1 resin particle b) HIPS particle c) concentric spherical shell (CSS) particle d) pools of low molecular weight polybutadiene as pure rubber particles (from Ref. [34] courtesy of Pergamon Press)... 

Chapman, A.V. Tinker, A.J. The effect of low molecular weight polybutadiene as processing aid on properties of silica-filled rubber compounds. Kautschuk Gummi K 2003, 56, 533. 

Until the early 1970s, all ED binders used industrially were based on maleinised natural oils, acidic alkyd resins or epoxy resin esters. Later, binders based on maleinised polybutadiene oils (LMPBs= low-molecular-weight polybutadienes) also came into industrial use, particularly in Western Europe. All these systems were of the anionic type, i.e. their water solubility and their deposition at the anode were due to the presence of carboxylate groups in the binder molecules. More recently, cathodic ED, with binders carrying cationic groups (e.g. -N 2h)j has proved to be an interesting alternative. This paper describes development work directed towards improving the corrosion resistance of anionic, and more briefly, cationic ED binders. 

Cansarz, I. and Laskawski, W. 1979. Peroxide-initiated crosslinking of maleic anhydride-modified low-molecular-weight polybutadiene. I. Mechanism and kinetics of the reaction. 

Boi greve, R. J. M. and Caymans, R. J. 1988. Impact modification of poly(caprolactam) by copolymerization with a low molecular weight polybutadiene. Polymer 29 1441-1446. 

The micelles formed when styrene-butadiene diblock copolymer is mixed with a large excess of low molecular weight polybutadiene were studied by Rigby and Roe (by SAXS) and by Selb et al. (by SANS). The first group employed three block... 

Fig. 18. The critical micelle concentrations of three styrene/butadiene diblock copolymer samples in the matrix of low molecular weight polybutadiene are plotted against temperature. The approximate compositions (stytene vs. butadiene) of the block copolymers are indicated.. (From Rigby and Roe )...

Low-molecular-weight polybutadiene oils result when the polymerization is catalyzed by a mixed system of butyllithium, 1,2-bis(dimethylamino)ethane, and potassium z-butanolate [110-112]. With 1,4-dilithium-1,1-4,4-tetraphenylbutane it is possible to get bifunctional living polymers (seeding technique) [113-118]. 

Low molecular weight polybutadienes (LMWPBs) have been employed in the past for UV curable coatings. However, one must expose these LMWPB formulated coatings to UV radiation for an excessively long period time to achieve an acceptable level of curing. 

The earhest information with regard to oxidized HRs appeared between 1955 and 1966 and relates to oxidized LMWPBs (low molecular weight polybutadienes) launched by Phillips under the trade names Butarez 200 and Butarez 300 [225,226], and to hquid copolymers of butadiene with 20% styrene, obtained by Esso. Research under the trade names Buton 200 and Buton 300 [227—229]. 

Grafting of maleimide copolymers on conjugated diolefin elastomers has been discovered as a route to new molding resins with improved physical properties.Low-molecular-weight polybutadiene, with substantial 1,2-microstructure, have also been heated with bismaleimides and peroxides to obtain grafted prepreg materials. Composites prepared from these... 

Low molecular weight polybutadiene and butadiene-acrylonitrile copolymers terminated with carboxyl, vinyl, amine, epoxy, phenol, and hydroxyl groups have been widely used as toughening agents both for epoxy and polyester resins. Thermally reactive isoprene-acrylonitrile and ethylacrylate-butylacrylate copolymers have also been used [82,83]. 

Table 1 Commercial sources and properties of low molecular weight polybutadienes... 

---