Optical properties of polystyrene and polyarylate block copolymer and their control by morphology generation

Abstract

Relationship between phase morphology and optical properties of polystyrene and polyarylate (PS‐PAr) block copolymers synthesized from telechelic polystyrene has been investigated. In the PS‐PAr block copolymers, the PAr domains with higher melt viscosity were dispersed in the PS phase matrix with lower melt viscosity over the wide range of their composition from PS/PAr = 25/75 to 75/25 (wt ratio). The PAr domain size was dependent on the reactive ratio of PAr determined analogously by the mole fraction of the fed telechelic polystyrene. By controlling the mole fraction of the telechelic polystyrene more than 0.016 in synthesizing the PS‐PAr block copolymer, the size of PAr domains could be reduced to the microscopic scale (smaller than 100 nm). Then, the PS‐PAr block copolymers exhibited almost the same transparency as PAr in spite of the large difference in the refractive index between the PS and the PAr phase. Birefringence free condition for the PS‐PAr block copolymers was determined by not only the PS/PAr composition but also the balance in the degree of molecular orientation of these chains. The latter factor suggests that PS and PAr chains undergo inhomogeneous stress and relaxation history during the injection process. By controlling Mn (number average molecular weight) and weight fraction of the fed OH‐PS‐OH around 20 000 and 55 wt %, respectively, in the synthesis of the PS‐PAr block copolymer, the PS‐PAr block copolymer exhibited almost zero birefringence without any sacrifice of transparency. Because in the PS‐PAr block copolymer low birefringence and high transparency can coexist by controlling the adequate feeding condition in the synthesis process, the PS‐PAr block copolymer would be a promising material for optical applications, such as a substrate of optical disks or optical lenses. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 953–961, 2000

Phase morphologies and mechanical properties of high‐impact polystyrene (HIPS) and polycarbonate blends compatibilized with polystyrene and polyarylate block copolymer

“…We carried out research and development on polymer blends based mainly on polystyrene and polyarylate (PS–PAr) block copolymers 24–29. In our earlier publications, we proposed a novel synthetic procedure for a PS–PAr block copolymer (Fig.…”

“…In our earlier publications, we proposed a novel synthetic procedure for a PS–PAr block copolymer (Fig. 1)24–26 and reported its high potential for high‐precision optical applications 24, 25, 27…”

Phase morphology of polystyrene–polyarylate block copolymer/polycarbonate blends and their application to disk substrates

“…We carried out research and development on polystyrene–polyarylate (PS–PAr) block copolymers 6–12. In our earlier publications, we proposed a novel synthetic procedure of PS–PAr block copolymer utilizing a telechelic PS (Fig.…”

Synthesis of styrene-acrylonitrile random copolymers (SAN) and polyarylate block copolymers and the control of their mechanical properties by morphology generation

“…We have carried out research and development of polystyrene and polyarylate block copolymers (PAr–PS–PAr) aiming at a new high‐performance polymer, especially a resin for precise optical application 5–7. In the earlier publications, we have proposed a novel synthetic route of PAr–PS–PAr utilizing telechelic polystyrene (PS) 5.…”

“…In the earlier publications, we have proposed a novel synthetic route of PAr–PS–PAr utilizing telechelic polystyrene (PS) 5. PAr–PS–PAr was found to exhibit almost zero birefringence without any loss in transparency by controlling Mn and weight fraction of the fed telechelic‐PS around 20,000 and 55 wt %, respectively, in the synthesis process 7. Although Mn of the fed telechelic‐PS should be controlled less than 20,000 to obtain transparent PAr–PS–PAr,7 PAr–PS–PAr with such small Mn of PS segment shows too brittle behavior to be injection‐molded.…”