Poly -3-methylpentene

The molecular weight of the polymer decreases sharply at the beginning of the reaction, and then more slowly. The rapid decrease is assigned to the breaking of abnormal weak structures distributed at random along 

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Poly(ethylene terephtlhalate) Phenol-formaldehyde Polyimide Polyisobutylene Poly(methyl methacrylate), acrylic Poly-4-methylpentene-1 Polyoxymethylene polyformaldehyde, acetal Polypropylene Polyphenylene ether Polyphenylene oxide Poly(phenylene sulphide) Poly(phenylene sulphone) Polystyrene Polysulfone Polytetrafluoroethylene Polyurethane Poly(vinyl acetate) Poly(vinyl alcohol) Poly(vinyl butyral) Poly(vinyl chloride) Poly(vinylidene chloride) Poly(vinylidene fluoride) Poly(vinyl formal) Polyvinylcarbazole Styrene Acrylonitrile Styrene butadiene rubber Styrene-butadiene-styrene Urea-formaldehyde Unsaturated polyester... 

Poly(4-Methylpentene-1). It was first discovered by Natta, later researched by many companies for synthetic fiber, and finally commercialized by ICI as a specialty molding resin. It is mainly isotactic, 40-65% microcrystalline, and has the lowest density of any plastic, 0.83, which may be approaching the theoretical minimum. 

MHE) and of isopropylvinylether with sec-butylvinylether. The binary mixtures of isotactic poly-4-methylpentene with isotactic poly-4-methyl-hexene and of isotactic poly-i-propylvinylether with isotactic poly-see-butylvinylether were also examined. 

Natta, Allegra, Bassi, Carlini, Chiellini, and Montagnoli (26) studied the binary mixtures of isotactic poly-4-methylpentene (P4MP) with isotactic poly-4-methylhexene (P4MHE), of poly-t-propylvinylether (PIPVE) with poly-sec-butylvinylether (PSBVE), or P4MP with PIPVE and of P4MHE with PSBVE (Fig. 10). 

Fig. 10. Variation of the a axis of the tetragonal unit cell of poly-4-methylhexene/ poly-4-methylpentene mixtures as a function of the composition (from Macromolecules, in press)...

Poly (4-methylpentene-l) possesses a largely isotactic structure with over 40% crystallinity. Characteristic properties are its high transparency and very low density of 0.83 g/cm3, as well as its applications at high temperatures up to 150 °C. 

Methylbutene-l, 4-methylpentene-1 and 5-methylhexene-l represent a homologous series. Thus, it is conceivable that intramolecular hydride shift polymerization will also occur with the latter two monomers. Indeed NMR spectra seem to suggest that a predominantly 1,4 and 1,5 type isomerization polymerization occurs when 4-methylpentene-1 and 5-methylhexene-l are reacted with catalysts of the Lewis acid type at low temperatures (—73° C.) (163). According to the NMR evidence, low temperature cationic poly(4-methylpentene-l) shows only 2 sharp peaks, characteristic for the CH3 and CH2 groups. This is in agreement with a gem. dimethyl structure of the a,a-dimethylbutane type ... 

Transparency. Some applications of plastics require transparency. Amorphous plastics should be able to transmit light. Some factors which prevent transparency include unsatura-tion/light absorption, crystallinity, fillers and reinforcing fibers, and use of rubber particles to increase impact strength. The plastics most often used for their transparency are poly(4-methylpentene-l) (TPX), poly(methyl methacrylate) (almost equal to glass), cellulose acetate, propionate, and butyrate, polycarbonate, and polysulfones (slightly yellow). As a research challenge, it is quite possible that fillers and rubber particles could... 

Individual Specialties. There are a number of special plastics which are used for their individual special properties and applications. Poly(4-methylpentene-l) combines rigidity, impact resistance, heat resistance, transparency, and chemical resistance, making it a unique replacement for glass in chemical... 

Polyphthalate carbonate Polyethersulfone Poly-4-methylpentene-l Good thermal properties, autoclavable Excellent thermal stability, resists creep UV/moisture sensitive, high crystalline melting point, lowest density o all thermoplastics... 

Figure 8-16. Helical segments Left, isotactic poly-4-methylpentene having 3.5 monomeric units per pitch Right, alpha-helix having 3.7 amino acid residues per pitch [17],...

Charlet, G. Ducasse, R. Delmas, G., "Thermodynamic Properties of Polyolefin Solutions at High Temperature 2. Lower Critical Solubility Temperatures for Polybutene-1, Polypen-tene-1 and Poly(4-methylpentene-1) in Hydrocarbon Solvents and Determination of the Polymer-Solvent Interaction Parameter," Polymer, 22, 1190 (1981). 

Zoller, P., "The Specific Volume of Poly(4-methylpentene-1) as a Function of Temperature (30-320C) and Pressure (0-2000kg/cm2)," J. Appl. Polym. Sci., 21, 3129 (1977). 

Rastogi, S., Hohne, G. W. H., and Keller, A., Unusual pressure-induced phase behavior in crystalline poly (4-methylpentene-l) Calorimetric and spectroscopic results and further implications. Macromolecules 32, 8897 (1999). 

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