Poly 4-methyl pentene isotactic

Additional examples of isomorphism include poly(isopropyl vinyl ether)/poly(sec-butyl vinyl ether) (PiPVE/PsBVE) and isotactic poly(4-methyl pentene)/isotactic poly(4-methyl hexene) (iP4MP/iP4mH) [314]. PiPVE/PsBVE blends were cocrystalline over the entire composition range, whereas iP4MP/iP4mH blends were isomorphic only in the range of 0-25 wt% of either constituent. For these blends, the chain axes and chain symmetries are identical, thus isomorphic behavior is possible. HDPE/LLDPE blends have been noted to be cocrystalline within limits of the comonomer incorporation in LLDPE. A comprehensive study of this... 

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... 

Poly(methyl methacrylate), isotactic Poly(4-methyl pentene-1) Poly(o-methyl styrene) Polyoxybutylene... 

Isotactic poly-(R)-3-methyl-l-pentene Isotactic poly-(S)-3-methyl-l-pentene... 

The intramolecular interaction energy was calculated for five isotactic polymers, namely, isotactic polypropylene, poly(U-methyl-l-pentene), poly(3-methyl-1-butene), polyacetaldehyde, and poly(methyl methacrylate) (23). The molecular structures of the first four polymers have already been determined by x-ray analyses as (3/1) (2k), (7/2) (18,25.,26), (U/l) (21), and (U/l) helices (28), respectively. Here (7/2) means seven monomeric units turn twice in the fiber identity period. For isotactic poly(methyl methacrylate) (29), a (5/l) helix was considered reasonable at the time of the energy calculation in 1970, before the discovering of... 

Figure 38 13C NMR of poly(4-methyl-1 -pentene). Isotactic, from rac-F Cp-Biilnd ZrC /MAO (bottom) syndiotactic, from Me2C(Cp)(9-Flu)ZrCI2/MAO (middle) atactic, from C2H4(9-Flu)2ZrCI2/MAO (top).

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. 

The case of conformational isomorphism of lateral groups occurs, for instance, in the crystal structure of isotactic poly(S-3-methyl-pentene), characterized by the presence of fourfold helices of only one sense (left-handed), with lateral groups which may adopt statistically two conformations of minimum energy [99,103]. 

Particular studies of the IR spectra of polymers include isotactic poly(l-pentane), poly(4-methyl-l-pentene), and atactic poly(4-methyl-pentene) [18], chlorinated PE [19], aromatic polymers including styrene, terephthalic acid, isophthalic acid [20], PS [21, 22], styrene-glycidyl-p-isopropenylphenyl ether copolymers [23], styrene-isobutylene copolymers [24], vinyl chloride-vinyl acetate-vinyl fluoride terpolymers [25], vinyl chloride-vinyl acetate copolymers [26], styrene copolymers [27], ethylene-vinyl acetate copolymers, graft copolymers, and butadiene-styrene [28] and acrylonitrile-styrene copolymers [29]. 

Similarly, isotactic poly(4-methyl pentene) has been crystallized with several different unit cells with different ordered conformations in some cases.(264)... 

Poly(4-methyl-l-pentene) (isotactic form) Square-based hollow pyramid ... 

Isotactic poly(4-methyl-1-pentene) Atactic poly(4-methyl-1-pentene) Isotactic poly(vinylcyclohexane)... 

It is pertinent to recall the work of Charlet et al. mentioned in Section II in which thermally reversible gels of isotactic poly(4-methyl pentene-1) (P4MP1) in cyclopentane or cyclohexane exist above the dissolution temperature of chain folded crystals. It was suggested that the association junctions responsible for these gels arise because of helical sequences which persist even above the boiling point of the solvent. The presence of helical segments in or-PS may play a role in connection with the af-PS gels. ... 

The synthesis of isotactic polymers of higher a-olefins was discovered in 1955, simultaneously with the synthesis of isotactic PP (1,2) syndiotactic polymers of higher a-olefins were first prepared in 1990 (3,4). The first commercial production of isotactic poly(l-butene) [9003-29-6] (PB) and poly(4-methyl-l-pentene) [9016-80-2] (PMP) started in 1965 (5). 

Figure 2.10 Maps of conformational energy of various isotactic polymers as function of backbone torsion angles 0i and 02 (a) Isotactic polystyrene, (b) polypropylene, (c) poly(l-butene), and (d) poly(4-methyl-l-pentene). Succession of torsion angles. .. 0i020i02 [s(M/N) symmetry] has been assumed. Isoenergetic curves are reported every 10 (a,c,d) or 5 (b) kJ/mol of monomeric units with respect to absolute minimum of each map assumed as zero.

Data concerning the chain conformations of isotactic polymers are reported in Table 2.1. In all the observed cases the torsion angles do not deviate more than 20° from the staggered (60° and 180°) values and the number of monomeric units per turn MIN ranges between 3 and 4. Chains of 3-substituted polyolefins, like poly(3-methyl-l-butene), assume a 4/1 helical conformation (T G )4,45,46 while 4-substituted polyolefins, like poly(4-methyl-1-pentene), have less distorted helices with 7/2 symmetry (T G )3.5-39 When the substituent on the side group is far from the chain atoms, as in poly(5-methyl-1-hexene), the polymer crystallizes again with a threefold helical conformation (Table 2.1). Models of the chain conformations found for the polymorphic forms of various isotactic polymers are reported in Figure 2.11. 

---