Polymer liquid-crystalline blends with engineering polymers

Ramanathan, R., Blizard, K., and Baird, D., Characterization of blends of liquid crystalline polymers with engineering thermoplastics, SPE ANTEC 34 23... 

Specific blends, which could offer an interesting combination of properties with proper com-patibilization, include PPS/PSE, PEl/PPS, PA/PSE, PA/PEI, and PC/PPS. Patent activity has been noted for most of these blend combinations as well as other selected blends involving engineering polymers as noted in Table 17.3. A number of recent patent and published papers have discussed blends of engineering polymers with various specialty polymers including high temperature polymers, liquid crystalline polymers (LCP s), conductive polymers, and as matrix materials for molecular composites. These will be discussed in the following sections. 

Novel Composites from Blends of Amorphous and Semicrystalline Engineering Thermoplastics with Liquid-Crystalline Polymers... 

In spite of the promising performances of the liquid-crystalline polymers, their use is limited to few practical application. This is due to the high pronounced anisotropy of orientation and properties of LCP processed in the pure state. The apparent contraddiction can be avercome by blending the mesomorphous polymer with ordinary engineering thermoplastics. 

Description of the mechanical properties of polymer composites are also made by considering the properties of particulate-long fiber and laminate composites through the different models generated in the literature. It is shown that, many advantages can be derived by use of liquid crystalline compounds as reinforcing fillers to produce blends with engineering thermoplastics. 

It has also been found that the properties of ordinary engineering polymers can be greatly improved by blending them with thermotropic liquid crystal polymers. Usually the processing properties are also improved. The fact that the materials are biphasic is not a disadvantage. The predominantly flexible phase contains some liquid-crystalline sequences which provide a certain amount of reinforcement in these regions. Costs are lower than for pure liquid-crystalline materials. 

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