Dibutyl phthalate, physical properties

Uses. Phthabc anhydride is used mainly in plasticizers, unsaturated polyesters, and alkyd resins (qv). PhthaUc plasticizers consume 54% of the phthahc anhydride in the United States (33). The plasticizers (qv) are used mainly with poly(vinyl chloride) to produce flexible sheet such as wallpaper and upholstery fabric from normally rigid polymers. The plasticizers are of two types diesters of the same monohydric alcohol such as dibutyl phthalate, or mixed esters of two monohydric alcohols. The largest-volume plasticizer is di(2-ethylhexyl) phthalate [117-81-7] which is known commercially as dioctyl phthalate (DOP) and is the base to which other plasticizers are compared. The important phthahc acid esters and thek physical properties are Hsted in Table 12. The demand for phthahc acid in plasticizers is naturally tied to the growth of the flexible poly(vinyl chloride) market which is large and has been growing steadily. 

There are several plasticizers for PVC that may be used in propellants. Weil (19) mentions sebacates, phthalates, adipates, and glycol esters of higher fatty acids as being desirable. Dibutyl sebacate, dioctyl sebacate, and 2-ethylhexyl adipate are all good. The plasticizer has a most important effect on the physical properties of the cured propellant and the variation of these properties with temperature. Long chain, aliphatic plasticizers impart improved low temperature flexibility, and hence are preferable to aromatic plasticizers such as the phthalates. An increase in plasticizer viscosity leads to an increase in viscosity of the mixed pro-... 

Non-reactive diluents. These diluents are low-viscosity materials which do not have any reactive sites and thus do not react with the epoxy systems. These diluents generally impart flexibility and improve the impact resistance, giving better thermal mechanical shock resistance. However, there is a sacrifice in physical strength, chemical resistance and high-temperature performance. Addition of 30 parts non-reactive diluent to 100 parts epoxy resin usually does not affect the physical properties of the system. Commonly used non-reactive diluents are nonyl phenol, furfuryl alcohol and dibutyl phthalate. 

The difference between plasticizers and tackifiers is somewhat arbitrary and the effect of this difference is described below in the section on Physical Properties. Plasticizers are typically lower in molecular weight and melting or softening point than are tackifiers. Hydrocarbon oils including aromatic, naphthenic, and paraffinic are commonly used with rubber-based adhesives. Phthalates, such as dioctyl phthalate or dibutyl phthalate, are more typically used in small amounts with acrylics. Since plasticizers are usually low molecular weight compounds, there is often more latitude in the chemical types that will be compatible with the base pol5mier because of the contribution from entropy of mixing. 

Dry cellulose nitrate is a colourless solid, much like cellulose in appearance but with a harsher feel. The straight material has a glass transition temperature of about 53°C but only plasticized material finds commercial use. In the case of surface coatings, plasticizers (such as dibutyl phthalate and tritolyl phosphate) are necessary to give films of acceptable flexibility and adhesion. For use in bulk form, the material is plasticized (with camphor) to permit compounding and shaping operations. Typical values of some physical properties of celluloid are shown in Table 11.5. 

Figure 10.7 Shear modulus and loss factor tan S for PVC plasticised with diethyl phthalate (DEP), dibutyl phthalate (DBF) and n-dioctylphthalate (DOP). (Reproduced from Neilsen, LE. Buchdahl, R. and Levreault, R., (1950) Mechanical and electrical properties of plasticised vinyl chloride compositions, j. Appl. Phys., 21, 607. Copyright (1950) American Institute of Physics.)...

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