Liquid crystalline polymers failure

The failure of poly(oxalic hydrazide) and polymers with high proportions of oxalyl units to yield liquid crystalline solutions is partly due to insufficient solubility in the solvents tested. Inadequate molecular weight may be a factor also. 

Besides the stress of state in the polymer, environmental stress cracking in polymers involves both solubility and absorption rate phenomena. Sensitizing media that cause ESC can be divided into two categories those that swell or wet the polymer and those that chemically react with the polymer. The medium may be gaseous or liquid. The former mechanism has been the subject of numerous studies and is commonly recognized as the primary cause of the majority of chemically induced failures of polymers. Although both amorphous and semicrystalline polymers are susceptible to ESC, it is well known that amorphous polymers tend to be more at risk. The close packing of chains in the crystalline domains of semicrystalline polymers acts as a barrier to fluid. 

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