THE EFFECT OF A PARTLY HYDROLYZED STYRENE-TERT-BUTYL ACRYLATE DIBLOCK COPOLYMER ON THE PROPERTIES OF POLY(2,6-DIMETHYL-1,4-PHENYLENE ETHER) (PPE) AND POLYAMIDE-6 (PA) BLENDS

The compatibilizing effect of a polystyrene-hydrolyzed poly(t-butyl acrylate) diblock copolymer (SBAH) on the phase structure, theological properties, and mechanical properties of immiscible poly(2,6-dimethyl-1,4-phenylene ether) (PPE) and polyamide-6 (PA) blends was investigated. The SBAH was prepared by sequential anionic polymerization of styrene and t-butyl acrylate, followed by acid-catalyzed hydrolysis of t-butyl acrylate block. Scanning electron micrographs show that the blends exhibit a more regular and finer dispersion when the SBAH of 47% hydrolyzed t-butyl acrylate block is added. By addition of a small amount of the block copolymer, the blends show non-Newtonian power-law behavior, and the contribution of storage modulus (G') to the total response increases. Solubility tests support the formation of graft copolymer by chemical reaction between amine groups of the PA and carboxyl groups of the SBAH. Both modulus and strength are improved about 20% with addition of the 3 wt% SBAH, while the elongation at break decreases notably; thus, the blends fail in a brittle manner.