On the basis of the concept of mesogen‐jacketed liquid crystalline polymers, a series of new methacrylate monomers, (2,5‐bis[2‐(4′‐alkoxyphenyl) ethynyl] benzyl methacrylate (MACn, n = 4, 6, 8, 10, and 12) and 2,5‐bis[2‐(6′‐decanoxynaphthyl) ethynyl] benzyl methacrylate (MANC10), and their polymers, PMACn (n = 4, 6, 8, 10, and 12) and PMANC10 were synthesized. The bistolane mesogen with large π‐electron conjugation were side‐attached to the polymer backbone via short linkages. Various characterization techniques such as differential scanning calorimetry, wide‐angle X‐ray diffraction, and polarized light microscopy were used to study their mesomorphic phase behavior. The polymer PMACn with shorter flexible substituents (n = 4) forms the columnar nematic (ϕN) phase, but other polymers with longer flexible tails (n = 6, 8, 10, and 12) can develop into a smetic A (SA) phase instead of a ϕN phase. The PMANC10 containing naphthyl can also form a well‐defined SA phase. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

Stir casting is a near net shape process that can cast the composite components directly. Fluidity is an important factor for mold filling in casting process, but the fluidity of composite slurry is poor due to the addition of SiCp. In this research, SiCp/A357 composites with 20wt.% SiCp were manufactured by mechanical stir casting. Effect of mechanical stirring and air pressure on the fluidity of SiCp/A357 composites were investigated with eight thin flow channels. The fluidity was compared at different rotating speed and air pressure. The results showed that the fluidity increased with rotating speed, which was more obvious in semi-solid interval. It was noticed that the fluidity decreased with air pressure, the gas involving and the cooling speed were aggravated with air pressure increasing, which reduced the fluidity.

The apparent viscosities of the semi-solid SiCp/A357 composites with 0vol.%, 10vol.% and 20vol.% SiC particles manufactured by stir casting were investigated using a Couette type viscometer, and the composite fluidity was examined with a test casting. The results showed that, the viscosities of the semi-solid SiCp/A357 composites decreased with an increase in shear rate, but increased with the increasing of solid fraction, and apparent viscosity of 10vol.% SiCp/A357 composite was the lower than that of 20vol.% SiCp/A357 composite at the same solid fraction; and the composite fluidity results were in a good agreement with the viscosity ones.