Polyarylates flexural moduli

Polyarylate (PAR)-b-PSt and PAR-b-PMMA for compatibiiizers are described 135,39,40). The addition of PAR-b-PSt (1-10 parts) to 100 parts of a blend of PAR-PSt (7w-3w) resulted in improvement of the tensile and flexural modulus (Fig. 4), and PSt dispersed particles were diminished from 1-5 microns to an order that is undetectable by SEM, indicating the excellent, compatibilizing effect of the block copolymer. The alloy thus formed exert the characteristic of PAR, an engineering plastic, as well as easy processability of PSt. Addition of PAR-b-PMMA (3 or 8 parts) to 100 parts of a blend of PAR-polyvinylidenefluoride (PVDF) (7w-3w) resulted in improved microdispersed state of PVDF due to compatibility of PMMA with PVDF, while segregation of PVDF onto the surface was controlled. 

Accordingly, we have evaluated the flexural modulus of injection molded specimens of CP-HQ/BB having higher F-values than those of Me-HQ/BB polyarylates. The flexural modulus of injection molded specimens of Me-HQ/BB... 

The test pieces of polyarylates were obtained by injection molding using Sumitomo NESTAL injection molding machine(0.5 ounce).ASTM D790 was used for measuring flexural modulus of injection molded test pieces(thickness, 1/32 ). 

Thus,the relationship between the modulus of as-spun fibers and the modulus of injection molded test pieces is not clear,but the flexural modulus is depending upon the BB mol% of polyarylates and the BB mol% might be used as the parameter of the rigidity of polymer chains.We observed many plate-like fibrils and a few needle like fibrils on the cross section of the flexural fractured test pieces of Me-HQ/BB/Cl-PEC(m/n=9/l).Then we prepared TLCPs with more rigid chemical structure,Me-HQ/BB/Cl-PEC(m/n=9.5/0.5),which showed a similar flexural modulus of 39 GPa as Me-HQ/BB/Cl-PEC(m/n 9/l),but X-ray diffraction pattens and SEM of these 2 polymers were quite different.The injection molded test pieces of Me-HQ/BB/Cl-PEC(m/n-9.5/0.5) showed lower degree of orientation and fewer fibrils than those of m/n=9/l as shown in Fig.7 and8(8). 

Amorphous polyarylates are light-amber transparent materials which exhibit mechanical properties comparable to that of unfilled PET in terms of tensile or flexural strength and modulus (Table 2.13) but are notably superior in terms of heat resistance (HDT = 174°C vs. 85°C for PET) and impact strength. 

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