Poly butene structure

Poly(butene-l sulfone) (PBS), a sensitive, positive, electron beam resist, is highly sensitive to 185-nm radiation (Table 3.4) (9). However, PBS does not absorb above 200 nm, and the sensitization has not been successful. Incorporation of pendant aromatic rings into the polysulfone structure extends the photosensitivity to the DUV and mid-UV regions (72). Himics and Ross (73) reported that carbonyl-containing poly(olefin sulfones) such as poly(5-hexen-2-one sulfone) are sensitive to UV-induced degradation and... 

Polyolefin homopolymers include polyethylene (PE), polypropylene (PP), poly-butene-1 (PB), polymethylpentene-1 (PMP), and higher polyolefins. Table 1.2 shows the structures of commercial polyolefin homopolymers. 

These homopolymers have structure units as shown in Fig. 2.1, where the asterisk indicates asymmetric carbon atoms. Thus, polypropylene (PP), poly (butene-1) (PB1), and poly(4-methylpentene-l) (P4MP1) have different tactic forms. The most important commercial polyolefins are polyethylene, polyisobutene, and the isotactic forms, that is, iPP, iPBl, and iP4MPl. Polyisobutene was first polymerized by the IG Farbenindustries (BASF) in the late 1920s. Polyethylene was first polymerized by ICI in the late 1930s in a branched form (1). Linear polyethylene... 

Draw the chemical structure of isotactic poly(butene-1). How is it prepared and used ... 

Polymorphism is observed relatively frequently in long-chain macromolecules, for which approximately isoenergetic structures exist. The stable crystal form of poly(ethylene), for example, possesses an orthorhombic lattice, but on elongation, triclinic and monoclinic modifications are observed. Three modifications are known in it-poly(propylene) a (monoclinic), P (pseudohexagonal), and y (triclinic). Since the molecules are in a 31 helix conformation in all the modifications, differences in the packing of the chain must be responsible for this polymorphism. The three modifications appear at varying crystallization temperatures. In it-poly(butene-l), however, the various modifications correspond to different kinds of helix, so that variations in conformation must be important (see also Table 5-5). 

It is now known that a wide array of polymers can be etched using potassium permanganate [273] although some care must be taken to limit the effect of artifacts. The list includes linear and branched PE, PP, PS, poly(4-methylpentene-l), poly (butene-1), PVF2, PEEK, PET and various copolymers such as EPDM terpolymers [273]. More recent work has shown that even liquid crystalline polymers can be etched by a variation of this method. Controls and complementary microscopy are essential to ensure that the experimentalist is not led astray imaging artifacts, hills and valleys or nussing fine structure, lost in the wash baths. 

Spirals on a poly(butene-l) lamellar structure grown from solution are seen in the TEM micrgraphs in Fig. 24 [205]. Spiral growths are frequently found when crystallization is carried out nonisothermally or at high degrees of supercooling. 

High performance elastomeric butyl tapes are available for large window lite glazing in high-rise structures and for windshield sealing. These usually contain crosslinked butyl elastomers (20-40%) plus poly butenes, resinous tackifiers, and reinforcing fillers such as carbon black and platy talc. Chlorobutyl rubber compositions are available for faster and more thorough vulcanization. 

Zhang B, Yang D, De Rosa C, Yan S, Petermann J. Single crystal structure of form 1 syndiotactic poly(butene-l). Macromolecules 2001 34 5221-5223. 

When Rj is different from R2 in Formula (1.1) the carbon atom is asymmetric and may have d or 7 forms. If all the asymmetric carbon atoms have either d or 7 forms, the polymer chain is said to be isotactic. If these carbon atoms are instead alternating d and 7 , the polymer chain is said to be syndiotactic. If the d and 7 assignments are random along the chain, it is said to be atactic [8,18-20] (see Fig. 1.1). Isotactic polypropylene, poly(butene-l) and poly(4-methylpentene-l) are commercially available. Both isotactic and syndiotactic polypropylene and polystyrene have been synthesized, subjected to extensive investigation. The two isomeric polymers have different crystal structures and their atactic forms do not crystallize. Isotactic and syndiotactic polymers were originally developed by Natta and his coworkers [18, 19] at Milan Polytechnic and Montecatini. In recent years, there has been interest in producing polyolefins with controlled intermediate tacticities [20]. 

Multilayered materials owe their properties and behavior to the properties of and the interactions between the components (5). Each of the two or more components contributes its particular property to the total performance of the multilayered material. For example, in Pouch 1, Table II, the aluminum foil provides high oxygen and water vapor permeability resistance, poly (ethylene terephthalate) provides structural strength and stiffness, and the ethylene-butene copolymer provides a heat sealable layer. If the components of the multilayered materials interact then the whole would be something different than the sum of its parts. In other words, the properties of the components of the multilayered materials are not independent of one another but rather are interdependent. 

Most commercial polymers are substantially linear. They have a single chain of mers that forms the backbone of the molecule. Side-chains can occur and can have a major affect on physical properties. An elemental analysis of any polyolefin, (e.g., polyethylene, polypropylene, poly(l-butene), etc.) gives the same empirical formula, CH2, and it is only the nature of the side-chains that distinguishes between the polyolefins. Polypropylene has methyl side-chains on every other carbon atom along the backbone. Side-chains at random locations are called branches. Branching and other polymer structures can be deduced using analytical techniques such as NMR. 

Figure 5.1 The structure of poly(alkenoic acid)s containing acrylic, itaconic, maleic and 3-butene 1,2,3-tricarboxylic acid units.

The liquid is usually a 30-43 % solution of a poly(alkenoic add) which is a homopolymer of acrylic acid or a copolymer with itaconic acid, maleic add, or 3-butene 1,2,3-tricarboxylic add (Smith, 1969 Bertenshaw Combe, 1972a Jurecic, 1973 ESPE, 1975 Wilson, 1975b Suzaki, 1976 Crisp, Lewis Wilson, 1976a Crisp Wilson, 1974c, 1977 Crisp et al., 1980). The method of preparation has already been given in Section 5.3, and the structures of these alkenoic add units are shown in Figure 5.1. The molecular mass of these polyadds varies from 22000 to 49000... 

In the crystal structures of many other isotactic polymers, with chains in threefold or fourfold helical conformations, disorder in the up/down positioning of the chains is present. Typical examples are isotactic polystyrene,34,179 isotactic poly(l-butene),35 and isotactic poly(4-methyl-l-pentene).39,40,153,247... 

Such isomerizations are sometimes desired and sometimes are the cause of or explanation for unwanted structures. In the cationic polymerization forming poly(l-butene), nine different structural units have been found. Classical 1,2-hydride and 1,2-methide shifts, hydride transfer, and proton elimination account for these structures. 

D. Where there is no conflict with other guidelines, triple bonds are senior to double bonds, which in turn are senior to single bonds multiple bonds should be assigned the lowest possible locants. Thus, the polymer from 1,3-butanediene polymerized in the 1,4- mode is usually indicated as-(—C—C=C—C — )-but is named as though it were-( - C=C - C - C - )-and named poly(l-butene-1,4-diyl) with the appropriate cis- or tra i-designation. Polyisoprene, typically drawn as-(—CH2 —C(CH3)=CH—CH2 —) —is frequently named poly(2-methyl-1,3-butadiene) but is named as though its structure were-(C(CH3)=CH—CH2—CH2 — ) —with the namepoly(l-methyl-1 -butene-1,4-diyl). 

Poly(1-butene). Loy (31) reported that the spectrum of high energy-irradiated poly(1-butene) at — 190°C. gave a poorly resolved six-line spectrum, with a hyperfine splitting constant of 21 gauss, indicating that the radicals formed have the structure (XVI) ... 

In spite of the similarity of the structure of the monomer units the two corresponding isotactic polymers crystallize in two different chain conformations tiie helix of poly-3-methyl-l-butene contains four monomer units per turn (4/1) with a chain repeat of 6.85 A the helix of poly-4-methyl-l-pentene contains 3.5 units per turn (7/2) and has a repeat of 13.85 A. The copolymers tend to crystallize. Their chain conformation and cross sectional area in the crystal lattice are analogous to those of the homopolymer corresponding to the predominant comonomer. For 4-methyl-l-pentene contents higher than 50% some evidence exists that the system simultaneously contains both chain conformations. 

Kennedy and Thomas (1) first reported the synthesis of a crystalline poly(3-methyl- 1-butene) by cationic polymerization at —130°C. Preliminary HNMR studies indicated that the polymer was not simply a tactic modification of the conventional 1,2-polymer but, in fact, possessed a repeat structure which resulted... 

Kennedy et al. (4) developed a near-infrared method to determine quantitatively the amount of 1,3- and 1,2-structures in poly(3-methyl-l-butene). The structure ratio" P1>3/Pl2, the ratio of percent 1,3- to percent 1 -structures in the polymer,... 

The first objective of this work was to explore by high resolution H NMR and 13CNMR spectroscopy the detailed structures of poly(3-methyl-l-butene) and poly(4-methyl-l-pentene) obtained by cationic isomerization polymerization. 

The investigation of the 300 MHz spectrum of poly(3-methyl-l -butene) indicates that the conclusions drawn by previous workers (2—4) concerning the structures of the crystalline and amorphous polymers are essentially correct the crystalline polymer being almost entirely of the 1,3-structure and the amorphous polymer being a mixture of both 1,2- and 1,3-structures. Further, it has indicated that this method is useful for analysis of the composition of the polymer. Quantitative composition determination, however, has not been carried out, since it is felt that the accuracy of the previous estimates utilizing near infrared spectroscopy were satisfactory. 

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