HER Materials for Polyurethane Applications

With the development of technical grade HER (HER TG), the processing temperature of the HER was further lowered without sacrificing the physical and mechanical properties of the final cured cast elastomers. The major difference between HER HP and HER TG chain extenders is the presence of some higher molecular weight (MW) reactive aromatic diol monomer in the technical grade material. With this unique 

To develop low melting and highly processable aromatic diol extenders from resorcinol and ethylene carbonate (HER materials). 

To determine the nature of products or by-products formed by the resorcinol-ethylene carbonate reaction. 

To investigate how the high MW aromatic diol monomer affects the phase separation behavior of polyurethane elastomers. 

To examine the effect of various HER chain extenders on the physical, mechanical and dynamic mechanical properties of cast polyurethanes made with MDI-terminated prepolymers. 

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Loss compliance quantifies the heat generated during dynamic loading in applications like tyres, wheels and rollers. Polyurethane elastomers with lower loss compliance values will experience less heat build up and, consequently, may suffer fewer field failures [14]. Figure 8.8 shows the graph of loss compliance as a function of temperature for the cast elastomers made with HER extended materials. The results are summarised in Table 8.5. 

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