Polystyrene in dibutyl phthalate

In a number of experimental studies of polymer diffusion, molar mass exponents close to 2 have been found, though always with some deviations. For example, using radio-labelled molecules, the diffusion coefficient of polystyrene in dibutyl phthalate was found to follow the relationship... 

Polystyrene Solutions 23—300 MHz. Moore et al. (85,86) obtained complex moduli data in the range of 23-300 MHz by measuring the complex reflection coefficient of shear waves reflected from a solid-liquid interface. The measurements were performed for solutions of polystyrene in dibutyl phthalate over the concentration range of 3-20 Vol.-% (86). The result is shown in Fig. 4.4 where (rf — v1 rjs)/ (t] - vt rjs) is plotted against f(t] — v1 f]s) M/cR T, vx being the volume fraction of the solvent and / the frequency in Hz. It is seen that the... 

An analogous measurement has been reported for solutions of a polystyrene in toluene at 40 MHz (55). The value of [tf ] was evaluated as about 8 ml/g at 25° C from the mechanical impedance data given in the paper. This value is close to that for polystyrene in dibutyl phthalate suggesting that the effect of t]s on is small, if any. At least, it may be... 

N. Nemoto, T. Kojima, T. Inoue, and M. Kurata. Self-diffusion of polymers in the concentrated regime I. Temperature dependence of the self-diffusion coefficient and the steady viscosity of polystyrene in dibutyl phthalate. Polym. /., 20 (1988), 875-881. 

Illers and Jenckel [36] studied aPS plasticized with diethyl, dibutyl and dioctyl phthalate. The mechanical measurements of tan<5 at 1 Hz showed the a relaxation moving rapidly to lower temperatures with increasing plasticizer content. The (3 relaxation was submerged below the a relaxation in the plasticized systems. A relaxation process was reported with a peak temperature ranging from 180 up to 267 K on addition of diethyl, dibutyl and dioctyl phthalate, respectively. The authors called this relaxation process y but they were inclined to ascribe it to the motion of low molecular weight polystyrene dissolved in discrete droplets of plasticizer. According to Heijboer [4], this can also be a motion within the plasticizer molecule, e.g. of the n-butyl group in dibutyl phthalate. 

Fig.4.4. Reduced dynamic viscosity at high frequency (rf —1>, t] s)/(ri — t>, tj,) plotted against reduced angular frequency f(rj — vx tjs) M/cR T for polystyrene solutions in dibutyl phthalate. Numbers represent concentrations in g/dl. Filled circles are extrapolated values at v2 — 0 (<%>)...

Hydrophobic polymers and films, such as paraffin wax and poly (vinyl chloride), show no change in stiffness modulus when flooded with water. On the other hand, butyl alcohol on a paraffin wax film causes a slow, slight increase of stiffness modulus over a period of several minutes. The effect of benzene on paraffin films is similar to that of methanol on PVA. A poly (vinyl chloride) film is unaffected by plasticizers such as dimethyl and diethyl phthalate over short time periods. However, PVC gives rise to the ultrasonic modulus anomaly when contacted with tetrahydrofuran, a strong solvent for PVC. The plasticizing effect of dibutyl phthalate on polystyrene has been demonstrated by ultrasonic impedometry (16). No anomalies were found. 

The technique involves first producing a seed latex by emulsifier-free emulsion polymerisation. A polystyrene latex of about 1 pva diameter is usually used. The seed particles are initially swollen using a microemulsion of a free radical initiator and a low molecular weight activating solvent , such as dibutyl phthalate, emulsified in water by sonication using sodium dodecyl sulphate as stabiliser. The seed... 

Pezzin et al. found the same kind of behavior exhibited by polyvinyl chloride PVC in two different plasticizers, dibutyl phthalate, DBP, and dicyclohexylphthalate, DCHP [62,63]. The same two equations provided excellent fits to the PVC solution data (see Fig. 12.9). For polystyrene dissolved in w-tricresyl phosphate, TCP, additional factors were noted. 

Williamswho investigated the plasticization of polystyrene. When this dielectrically rather inert polymer is added to dibutyl phthalate, the single relaxation process of the pure ester is initially broadened, but at polystyrene concentrations above 40%, two broad relaxations develop. Analysis suggests that the low temperature process involves ester molecules which are relatively free to relax their dipoles in whole or in part, whilst the high temperature relaxation involves the cooperative motion of polymer chain and ester dipoles. This latter process thus being responsible for plasticization. 

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