Many attempts to upgrade polystyrene have been made in the past. One of the last and most popular examples is the upgrading of polystyrene by stereo-controlled polymerization of styrene monomer, yielding a syndiotactic material. But the property profile of polystyrene can also be improved by stiffening the polymer chain with bulky groups. 1,1-Diphenylethylene (DPE) was selected as a monomer with such a bulky group and was copolymerized anionically with styrene to give an amorphous copolymer with a statistical chain structure which was called 'super-polystyrene'. In this paper the conditions of the anionic polymerization and the properties of the resulting materials are described. Depending on the DPE content, the glass transition temperature can be varied from 104 • C to 180 • C. Up to a DPE content of 15%, these styrene-DPE copolymers are miscible with GPPS as well as with syndiotactic polystyrene. Toughening of the transparent polymers was achieved with glass fibers and grafted rubber particles. Block copolymerization with minor amounts of butadiene yielded a tough and transparent polymer. Thermoplastic elastomers with an enhanced softening point having the block sequence S /DPE-b-Bu-b-S /DPE and S /DPE-b-EB-b-S /DPE were also prepared.
Mischungen aus Polystyrol und Styrol‐Butadien‐Zweiblockcopolymeren führen bekanntermaßen zu einem Zweiphasensystem mit definierter morphologischer Struktur. Entsprechend dem Phasenvolumenverhältnis von Styrol zu Butadien im Kautschuk enstehen Zellen‐, Labyrinth‐ und Kapselteilchen sowie inverse Zylinder‐ und Kugelstrukturen.
Untersuchungen dieser Art wurden auf Styrol‐Butadien‐Styrol‐ und Butadien‐Styrol‐Butadien‐Dreiblockcopolymere ausgedehnt. Unter bestimmten Bedingungen bilden diese Sequenzpolymeren Überstrukturen, die nach ihrem Erscheinungsbild Kugelhaufen, Fadenhaufen bzw. Mehrschalenteilchen genannt wurden. Voraussetzung für die Bildung dieser Strukturen ist es, daß die außenliegenden Blöcke zwei verschiedenen Domänen angehören und das mittlere Segment der kohärenten Phase zuzurechnen ist.
SUMMARYPolystyrene is with a present day sales volume of 8,5 million tons a year one of the most important thermoplastics worldwide. Its unique property profile makes polystyrene an ideal material for housings, refrigerator inliners and demanding packaging applications, when transparency and/or surface quality as well as stiffness are important. Its economic success is due to its favourable price/performance ratio and also not least to its excellent processability as an amorphous material.In this contribution the versatility and potential for innovation of polystyrene and its copolymers are discussed. Using standard and impact modified polystyrene, it is shown how the maturity of the polymerisation process, the broad spectrum of product modifications as well as processing know how of this class of materials have helped to promote the breakthrough of this product to an acknowledged plastic material.Modern polystyrene variations are increasingly meeting the special property requirements of other materials, like for example high heat resistant PPEPS-I blends, weather resistant ASA and AES plastics, tough and crystal clear star polymers or hydrogenated and unhydrogenated elastomers.A special feature of polystyrene is that it is one of the few monomers which can be polymerised using all the known methods for vinyl monomers to produce high molecular weight products. Thus the newest Vortrag anlanlich der Tagung der Fachgruppe "Makromolekulare Chemie" der GesellschaR Deutscher Chemiker iiber "Klassische Polymere im Auhind" in Dresden, 25.
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