Effect of Primary Hydroxyl Concentration on One-Shot Elastomer Processability

1 Effect of Primary Hydroxyl Concentration on One-Shot Elastomer Processability 

The reactivity of PPG polyols can be increased by reacting with EO, which ring opens to form a primary hydroxyl group. A 100% primary hydroxyl content cannot be achieved using this approach since EO has a tendency to form chains instead of distributing evenly to each secondary hydroxyl group however, it is well known that a 100% primary content is not required to achieve one-shot processability. The effect of the primary hydroxyl content on the processability of a one-shot elastomer system is discussed next. 

To determine the effect of the polyol primary content on the processability of a one-shot system, two 4000-MW, ultra-low monol PPG diols, which were EO-capped to obtain primary contents of 80 and 87 percent were prepared. These were compared with a 

The previous studies led to the development of three products, a 2250-MW diol (Acclaim Polyol 2220), 4000-MW diol (Acclaim Polyol 4220) and a 6000-MW triol (Acclaim Polyol 6320). Table 9.4 shows the typical properties of these new higher-reactivity, ultra-low monol PPG polyols. The behaviour of these products in one-shot systems is discussed below. 

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