Poly 4-methyl pentene

4-Methyl- 1-pentene belongs to the class of the hexenes. It can be produced by the catalytic dimerization of propylene (1,2). The dimerization of propene with a high selectivity to 4-methyl-l-pent-ene can be achieved in the presence of a catalyst, which is obtained by dispersing metallic sodium and metallic potassium on a molded article comprising an anhydrous inorganic potassium compound and elemental carbon (3). 

Maleic acid Fumaric acid Itaconic acid Citraconic acid Crotonic acid 

Acrylic acid Metacrylic acid Itaconic acid 

TPX is polymerized commercially by a Ziegler-Natta polymerization. Mostly copolymers are on the market. Besides a Ziegler-Natta polymerization, also a living polymerization process has been reported. 

The homopolymerization and copolymerization of 4-methyl-l-pent-ene is generally carried out in a batch polymerization process (5). Batch polymerization refers to a polymerization method in which a quantity of the monomers are polymerized in a reaction vessel and then the resulting polymer is recovered from that reaction vessel upon the desired level of polymerization of the monomers. It is desirable to carry out such processes under conditions, which result in a slurry of particles of the desired polymer or copolymer in the polymerization diluent rather than a solution of the polymer or copolymer. The formation of such a slurry aids in the separation and purification of the resulting polymer. 

Another commercially produced polyolefin is isotactic poly(4-methyl pentene-1). The polymer carries a trade name of TPX. This material is known for high transparency, good electrical properties, and heat resistance. PoIy(4-methyI pentene-1) has a density of 0.83 g/cm. This polyolefin exhibits poor load-bearing properties and is susceptible to UV degradation. It is also a poor barrier to moisture and gases and scratches readily. This limits its use in many applications. 

Poly(4-methyl pentene) is produced by the same process and equipment as polypropylene. A post finishing de-ashing step, however, is required. In addition, aseptic conditions are maintained during manufacture to prevent contamination that may affect clarity. 

4-Methyl pentene-1 is produced by the dimerization of propylene with potassium on graphite as catalyst at 135-165°C under 40-60 bar. It is presumed that [CH3CH=CH2] K and KH are primarily formed. The monomer is then polymerized with Ziegler catalysts. 

The polymer, which is isotactic with 40% crystallinity, is still crystal clear. It possesses the lowest density of all synthetic polymers ( 0.83 g/cm ). The glass-transition temperature is 40°C, and the softening point is 179°C. Consequently, the polymer can be sterilized and used continuously 

---

Hence at room temperature there are no solvents for polyethylene, polypropylene, poly-4-methyl-pentene-l, polyacetal or polytetrafluoroethylene, but at temperatures of about 30°C below their melting point solvents of... 

Other polyolefins A variety of other crystalline polyolefins are available such as polybutene-1 (improved creep resistance over polyethylene), poly-4-methyl pentene-1 (excellent temperature deformation resistance) and ethylene-vinyl acetate (greater flexibility). 

THF (5 g) mixed with 0.1 ml 10 NHC1 and added slowly to 5 g of titanium isopropoxide with fast stirring. This sol was then mixed with a 10 wt% solution of triethoxysilane capped PF or PEK in THF. The final solution was cast into poly(4-methyl-pentene) Petri dishes and covered for drying and curing at 60 °C for 24 h. Films were then removed and annealed at 200 °C for 15 min... 

I. Pinnau, Ultrathin Ethyl Cellulose/Poly(4-methyl pentene-1) Permselective Membranes, US Patent 4,871,378 (October 1989). 

Poly-buten-(l) und Poly-4-methyl-penten-(l), das Poly-1,4-cis-butadien, Poly-1,4-trans-butadien,... 

Hard and tough, stiff solids T[Pg.30]

A linear polymer is one in which each repealing unit is linked only to two others. Polystyrene (1-1), poly(methyl methacrylate) (1-34), and poly(4-methyl pentene-1) (1-35) are called linear polymers although they contain short branches which arc part of the monomer structure. By conirast, when vinyl acetate is polymerized by free-radical initiation, the polymer produced contains branches which were not present in the monomers. Some repeating units in these species are linked to three or four other monomer residues, and such polymers would therefore be classified as branched. 

Used as an antioxidant and thermostabilizer for polypropylene, polyethylene, impact resistant polystyrene, poly-4-methyl-pentene. Can be used as a stabilizer for natural and synthetic rubber, polyvinyl chloride. A copolymer of acrylonitrile with butadiene and styrene, polyacetals, alkyde resins, polyamides and polyesters. 

The re-entrant or Tammann loop-shape phase diagram as observed in proteins is also found in other systems and has been connected to exothermic disordering [88]. In this particular case, nematic - smectic A transitions in liquid crystals and the phase behaviour of a crystalline polymer, poly(4-methyl-pentene-l), the phase behaviour can be understood by... 

Glycidyl methacrylate High density polyethylene Isotactic copolymer of styrene and p-methyl styrene Isotactic poly(ethyl methacrylate) Isotactic poly(methyl methacrylate) Isotactic polystyrene Low density polyethylene Linear low density polyethylene Maleic anhydride Poly(4-methyl pentene) Random copolymer of phenyl ether and phenyl ketone... 

CH,CH(CH3), Poly-4-methyl pentene-1 62,000 Nonpolar, very bulky side group, amorphous... 

P4MP Poly (4-methyl-pentene-l) 830 25 238 Semi-brittle... 

---