Balata

The unusual resiHence of ionomers combined with ease of processing have resulted in widespread replacement of balata mbber as golf-ball covers. In order to obtain desirable backspin characteristics, low glass-transition ionomer compositions have been developed (10). Transparent coatings on bowling pins promote both longer life and improved playing performance. 

Natural mbber (Hevea) Natsyn 2200" Kuraray TP-301 Natural balata... 

Non-elastomeric chemical derivatives of natural rubber are discussed in Chapter 30 in which chemically related naturally occurring materials such as gutta percha and balata are briefly considered. 

An alternative source of the frani-1,4-polyisoprene is balata, obtained from Mimosups balata, occurring in Venezuela, Barbados and Guyana. The latex is thin and may be tapped in the same way as natural rubber. 

The coagulated material consists of about 50% polyisoprene and the remainder is primarily composed of resins. Deresinated balata has been used as an alternative to gutta pereha, which it resembles in properties and also in belting applications. It is still used for making high-quality golf ball covers but for the cheaper balls it has now been replaced almost entirely by the ionomers (see Chapter 11). 

Balatagummi, m. balata gum. bald, adv. soon, presently almost.—conj.—. . . now. . . then so — als, as soon as. baldlg, a. quick, early, baldigst, adv. very soon, as early as possible. haldmdgUchst, adv. as soon as possible. 

Since 1960, gutta-percha or synthetic balata has been replaced by ionomer for use as a cover material in golf balls. It is based on a combination of ethylene and a carboxylic acid. It can be processed at a reasonable temperature to produce good, tough ball covers. Because of higher processing temperature of the ionomer... 

The infrared spectra of hevea (natural rubber), balata (or guttapercha), the latter both in the crystalline (a) and the amorphous forms, and of synthetic polyisoprene are compared in Fig. 32. The hevea and balata (amorphous) spectra offer calibrations for cfs-1,4 and irans-1,4 structures, respectively, in the synthetic polymer. Owing to the presence of the methyl substituent, however, the spectral difference between the as and trans forms is slight both absorb at about 840... 

Fig. 32.—Infrared absorption spectra of hevea (natural as-l,4-polyisoprene), of balata (natural

The hard thermoplastic hydrocarbon obtained from the latex of Mimusops globosa. Balata has the same molecular formula as natural rubber (C5H8)n but has the tram polyisoprene structure whereas natural rubber has c/ s-structure. 

A class of hydrocarbons occurring in many essential oils of plants. They can be regarded as low-molecular weight polymers of isoprene (C5I I8)n. Dipentene is a terpene, while natural rubber, gutta percha and balata have been termed polyterpenes. 

Ceccherelli G, Piazzi L, Balata D (2002) Spread of introduced Caulerpa species in macroalgal habitats. J Exp Mar Biol Ecol 280 1-11... 

Before 1800 Cotton, flax, wool, and silk fibers bitumens caulking materials glass and hydraulic cements leather and cellulose sheet (paper) natural rubber Hevea brasiliensis), gutta percha, balata, and shellac 1839 Vulcanization of rubber (Charles Goodyear)... 

Natural rubber (Hevea brasiliensis) is as-poly-2-methyl-1,4-butadiene, and gutta-percha (Palaquium oblongi/olium) and balata (Minusops globosa) are polymers of isoprene (2-methyl-1,4-butadiene) with trans configurations. Neoprene is a polymer of 2-chloro-1,3-butadiene (chloroprene). 

This polymer is a hard plastic that occurs naturally as gutta-percha or balata. Since the trans isomer packs better than the cis isomer, it has a higher specific gravity, a higher degree of crystallinity, and a higher melting point (67 C) than the ds isomer of polyisoprene. The chemical and the solvent resistance of the trans polymer are simitar to those of the ds polymer. 

Wenn sich zwischen Kettenatomen Doppelbindungen befinden, dann konnen diese cis- oder trans-Struktur besitzen. Bei llnearen Homopoly-meren sind zwei Grenzfalle zu unterscheiden alle Doppelbindungen lie-gen in cis-Struktur oder in trans-Stniktur vor (wie bci Naturkautschuk bzw. Balata). Man spricht von cis- bzw. trans-taktischen Polymeren. 

Zum SchluB sei daran erinnert, daB viele in der Natur vorkommenden Polymere cbenfalls taktisch sind und einen hohen Grad an Taktizitat be-sitzen wie die mono-taktischen Vertreter Naturkautschuk und Balata odor die funffach taktischcn Polymeren, Cellulose und andere Polysaccharide. 

Cis-1,4 polyisoprene (natural rubber or synthetic isoprene rubber) and trans-1,4 polyisoprene (balata or guttah-percha) show strongly different properties. 

Some of the polybutadienes obtained with transition metal-based coordination catalysts have practical significance the most important is cA-1,4-polybutadiene, which exhibits excellent elastomeric properties. As regards isoprene polymers, two highly stereoregular polyisoprenes, a cA-1,4 polymer (very similar to natural rubber) and a trans- 1,4-polymer (of equal structure to that of gutta percha or balata) have been obtained with coordination catalysts. Various polymers of mixed 3,4 structure, amorphous by X-ray, were also obtained [7]. 

By contrast, cis- 1,4-polyisoprene is produced in limited amounts, since it is not price competitive with natural rubber (owing to the relatively high costs of manufacturing the isoprene monomer). The same applies to trans- 1,4-polyisoprene, which is more expensive than its natural counterparts gutta percha and balata. 

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