Page 547 - Carrahers_Polymer_Chemistry,_Eighth_Edition

510 Carraher’s Polymer Chemistry

CH
CH 3 3
H C O
3
O
O

CH 3 O
O (15.5)
O

3
H 3 C H C
TOTM

Compatibility is the ability to mix together without forming different phases. A good approach
to measure likelyhood of compatibility is solubility parameters (Section 3.2). Plasticizers with solu-
bility parameters and type of bonding similar to those of the polymer are more apt to be compati-
ble than when the solubility parameters are different. The solubility parameter for PVC of 9.66 is near
that of good plasticizers for PVC such as DOP with a solubility parameter of 8.85. Table 15.2 contains
solubility parameters for typical plasticizers.
The development of plasticizers has been plagued with toxicity problems. Thus, the use of highly
toxic polychlorinated biphenyls (PCBs) has been discontinued. Phthalic acid esters, such as DOP,
may be extracted from blood stored in plasticized PVC blood bags and tubing. These aromatic esters
are also distilled from PVC upholstery in closed automobiles in hot weather. These problems have
been solved by using oligomeric polyesters as nonmigrating plasticizers in place of DOP for appro-
priate situations. Recently, some limited tests have indicated a relationship of prenatal exposure
to phthalates and reproductive abnormalities of male babies. The chemical industry is monitoring
these results taking appropriate steps to limit or eliminate exposure to dangerous materials.

TABLE 15.2
Solubility Parameters of Typical Plasticizers
Plasticizer Solubility Parameter (H)
Paraffi nic oils 7.5
Dioctyl phthalate 7.9
Dibutoxyethyl phthalate 8.0
Tricresyl phosphate 8.4
Dioctyl sebacate 8.6
Triphenyl phosphate 8.6
Dihexyl phthalate 8.9
Hydrogenated terphenyl 9.0
Dibutyl sebacate 9.2
Dibutyl phthalate 9.3
Dipropyl phthalate 9.7
Diethyl phthalate 10.0
Glycerol 16.5

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