Bonding polybutene

The symbols have their usual meanings (] ). From measured values of NTj and ri on a poly (butene-1 sulfone) of degree of polymerization 700 the values of t (in nanosec.) shown in Table III are obtained. The discrepancy between the values of from NT and from ri, particularly marked for the side-chain motions, indicates the inadequacy of the single-Tg model. Nevertheless it is evident that the backbone motions are relatively rapid. (Comparison to polybutene-1 (jW) shows that SO2 groups retard the motion of the copolymer chains by a factor of about 50.) The question now becomes why are these rapid motions NMR-active but dielectrically inactive One possible type of motion which would account for this is shown in Fig. 9. Five backbone bonds and six main-chain atoms are involved, i.e. the sequence C-S-C-C-S-C, with concerted segmental transitions about two C-S bond, allowing interconversion... 

A. Jones Yes, I didn t show all the data. Most of the data is from the literature. Polystyrene data and polyisobutylene data at two field strengths can be accounted for by these lattice models based upon the three bond jump. Some recent data by Dr. Bovey on the polybutene was more difficult to fit with regard to the frequency dependence. (F. C. Schilling, R. E. Cais and F. A. Bovey, Macromolecules ]A, 325 (19T8).) Frequency dependent data I think is important information to acquire when trying to understand the dynamics. 

The polybutene structure also contains one carbon-carbon double bond at the end of the polymer chain [40]. The nature of this double bond is important in defining the ease with which it will undergo chemical modification. Normally it is found as the CIS- and franx-trisubstituted group, but polybutenes having the more reactive disubstituted vinylidene structure are now available. Fig. 2.2. Polybutenes have good stability as lubricant components, even whilst containing the residual unsaturation. It is possible to react the double bond to produce products such as lubricant dispersants, see Chapter 7, but the reaction is achieved only under certain controlled conditions. 

Puskas, I., Banas, E.M., Nerheim, A.G., 1976. Nature of double-bond in low-molecular weight polyisobutylenes and polybutene copolymers. J. Polym. Sci. Polym. Symp. 56, 191—202. Quirk, R.P., 1984. Recent advances in controlled grafting of elastomers. Rubber Chem. Technol. 57 (3), 557-582. 

The aim of this example is to determine a mode of production of polybutene to obtain a product similar to standard UV-10. This means, to produce a material with a greater concentration of terminal double bonds from the process variables and a commercial catalyst. 

In solvent-borne rubber adhesives, a variety of solvents can be chosen to control drying rate, adjust viscosity and dissolve important ingredients. Resins can be added to improve tack, wetting properties, heat resistance, bond strength and oxidation resistance. The most common resins nsed in rubber-based adhesives are rosins, rosin esters, and terpene, coumarone-indene, hydrocarbon and phenobc resins. Plasticizers and softeners reduce hardness, enhance tack and decrease cost of rubber adhesive formulations. Paraffinic oils, phthalate esters and polybutenes are typical plasticizers. Fillers are not often added to rubber adhesive formulations because they reduce adhesion. However they are sometimes used because they decrease cost and increase solution viscosity. Carbon black and titanium dioxide are also used to provide colour to the adhesives. Clays, calcium carbonate and silicates are also common fillers in rubber adhesive formulations. For water-borne adhesives, typically protective colloid, preservative, defoamers, wetting agents and emulsifiers are included in the formulations. 

Equations (7.21) and (7.22) may be generalized to the case in which the species are chemically different (with unequal segment volumes, Va and Vb) and applied to polymer blends (see Section 7.6.2.1). However, when this approach is applied to isotopic mixtures, the H- and D-labeled molecules may be regarded as different species with the same segment volume (F) and volume fractions, cpA = cpu and = (pD- The RPA (Eq. (7.22)) may then be fitted to the data with xhd as the only adjustable parameter [107-109, 112-114]. Measurements on polybutadiene [107,109], polystyrene [110], polybutene [109], polyethylene [114], and poly-dimethylsiloxane [111] confirm the existence of a universal isotope effect arising from small differences in volume and polarizability between C— H and C— bonds [107,112]. Table 7.4 lists typical values of the isotopic interaction parameter in the range 0.2 < < 0.8, where xhd has been shown to be relatively independent... 

Polybutene-based hot-melt adhesives are tough, partially crystalline, and their slow crystallization rates lead to long open times. Copolymers of butene result in softer and more flexible adhesives. In general, polybutene and its copolymers have low temperatures for recrystallization from the melt. This permits stress release in the adhesive bond, which may have been applied to cold surfaces. Polybutene and its olefinic copolymers exhibit good bonding to nonpolar surfaces but poor compatibility with polar substances. These hot-melt adhesives have been used on rubbery substrates and are available as pressure-sensitive adhesives. 

Polyolefins. Polyethylene, polypropylene, and polybutene can be bonded only after treatment to increase the surface energy, generally by oxidation, and make the surfaces receptive to bonding. Pretreatment can be carried out with an oxidizing flame, with oxidizing chemicals, or by electrical discharge. 

Polybutene is incorporated into polyolefines (frequently octene LLDPE) for these products. The film may have up to three coextruded layers with polybutene in two of them. This process has been well established for some years and data on such properties as the influence of polybutene on ultimate bond and rate of generation of tack properties have been produced by a polybutene supplier [3]. 

Polybutene exists in two isomeric forms depending on where the carbon double bond is positioned in the monomer molecule. If it is between the first and second carbon atoms in a linear molecule (Butene-1), then the chemically accurate name of the resulting polymer is PB-1. If it is a branched monomer... 

Formulation I at the end of this chapter is a suitable base. Preservation against bacterial attack is necessary, as also is a fungicide, as the dried film is open to the atmosphere. Zinc di-ethyldithiocarbamate performs both functions. It is sometimes found that an occasional batch of latex does not display a sufficient degree of self adhesion, and this may be overcome by adding a small amount of a high molecular weight plasticizer. A liquid polybutene added up to 10 pphr as a 50% emulsion is suitable. In some cases it may be necessary to improve the bond to the paper so that the envelope may not be opened without tearing the paper a polyvinyl acetate latex added at about 10 pphr has been found to achieve this without noticeable loss of self tack. 

For the purposes of this chapter, polyolefins are defined as polymers based on unsaturated aliphatic hydrocarbons containing one double bond per molecule. Polymers derived from unsaturated aromatic hydrocarbons and dienes are considered in later chapters. At the present time the principal commercial polyolefins are polyethylene (polythene), polypropylene, polyisobutene, polybutene and poly(4-methyl-l-pentene) together with related copolymers. These polymers are considered individually in subsequent sections after a brief account of relevant raw materials. 

In the Raman spectra of conformationally disordered polyethylene, the D-LAM mode found at a frequency (near 200 cm ) that is proportional to the concentration of gauche bonds [74]. This D-LAM mode is also observed in other molten vinyl polymers including polypropylene, polybutene and polystyrene. The presence of this Raman line in these polymers suggests a common structural basis although the chains themselves have different side chains [75]. In the vinyl polymers the band may appear as a doublet. For polypropylene, for example, there is a line near 200 cm and 400 cm and it is suggested that these two components are associated with the conformationally ordered (gt)4 polypropylene. 

---