3,3 - dibenzoic

Application of the ring opening reaction to disaccharide derivatives such as 4,6 4, 6 -di-0-benzylidene-a,a-trehalose affords the corresponding 6,6 -dibromo-4,4 -dibenzoate in good yield. 

Meso phases can be recognized and evaluated by X-ray measurements. Three-dimensionally crystalline polymers have a meridian at the equator, and also exhibit sharp diffraction reflexes in all other directions (see Figure 5-6). Other polymers only give sharp diffraction reflexes at the meridian. Examples of this behavior are poly(trimethylene terephthalamide) and poly(oxydi-ethylene-4,4 -dibenzoate). Such behavior is caused by longitudinal order in the chain direction, and lateral disorder in both other dimensions the crystals have one-dimensional order and two-dimensional disorder, which is characteristic of nematic meso phases (Figure 5-29). Smectic and cholesterinic meso phases are other one-dimensional oriented ordered systems. 

There have been many attempts to change the melt flow properties of a polymer by incorporating a small amount of an anisotropic or an immiscible polymer. For example, Brody [220,221] demonstrated a windup speed up to 5000 m/min by adding a small amount of copoly(chloro-l,4-phenylene ethylene dioxy-4,4 -dibenzoate/terephthalate) (CLOTH) or copoly(4-hydroxybenzoic/6-hydroxy-2-naphthoic acid) into nylon-6,6. More recently, Vassi-latos [222] disclosed the melt spinning of nylon-6,6 at speeds up to 6000 m/min with the addition of a minor amount of liquid crystalline polymers such as CLOTH. This technique clearly offsets some of the cost advantages of high-speed spinning. 

Lj-6,6 -dichlom-2,2 -diethoxy-1,1 -binaphthyl-4,4 -dibenzoateand L -6,6 -dichloro-2,2 -diben loxy-1,1 -binaphthyl-4,4 -dibenzoate. 

Tsai et al. [28] polycondensed methylenebis(4-phenylisocyanate) with a mixture of a,a -dihydroxy-poly(pentamethylene-4,4 -dibenzoate) and 0 ,a -di-hydroxy-poly(tetramethylene butane-1,4-dicar boxy late) ohgomers (Scheme 25). 

Methylenedioxy)dibenzoic anhydride Methylethylene 2,2 -dibenzoate Methylethylene 3,3 -dibenzoate Methylethylene 4,4 -dibenzoate Propylene 4,4 -sulfonyldibenzamide... 

Ethylene 2,2 -dibenzoate Ethylene 3,3 -dibenzoate Ethylene 4,4 -dibenzoate Isophthalaldehyde Terephthalaldehyde p-Xylylene isophthalate p-Xylylene terephthalate... 

---