Preparation and Characterization of Polyamides Composites with Poly(β-hydroxybutyrate) And Poly(vinyl alcohol) pp.1181-1206
Authors: (Aiman Eid Al-Rawajfeh, Hasan A. Al-Salah, Tafila Technical Univesity, Department of Chemical Engineering, Jordan)
Abstract: This chapter tackles all aspects of blending of two groups of polymers; a typical polyamide with either a typical polyester or a typical polyvinyl. Polyamide-6 (PA6), bacterial poly (β -hydroxybutyrate) (PHB) and poly (vinyl alcohol) (PVA) are typical polyamide, polyester and polyvinyl, respectively. PA6 is known to be high-strength engineering thermoplastic. Although it is ductile at room temperature, it becomes brittle under severe conditions such as high strain rates and/or low temperatures. This is due to the low crack propagation resistance of polyamides. PHB is a biodegradable and biocompatible thermoplastic polymer of high melting temperature (180 oC ) and crystallinity. PHB has attracted much attention as an environmentally degradable resin to be used for agricultural, marine and medical applications. One of the limitations of PHB for these applications is its brittleness and narrow processing window. Blending of friendly environmental biopolymers with synthetic polymers has proven to be a suitable tool to produce novel materials with combined characteristics in having both improved application properties and low cost advantages in material performance. PVA is a vinyl polymer of simple structure with a wide range of applications. It is a water soluble polymer. Commonly used PVA is atactic and usually obtained by radical polymerization of vinyl acetate with subsequent hydrolysis of the side group. In this chapter, the interaction parameters, crystallinity, miscibility and morphology of polymer blends (PB) of PA6/PHB and PA6/PVA have been studied at different weight fractions and different crystallization temperatures. The equilibrium melting points ( o mB T ) values for individual blends were determined by the method of Hoffman and Weeks. The interaction parameters were calculated using the Nishi-Wang equation, which is based on the Flory- Huggins theory. A corrected interaction parameter ( ' ij χ ), accounting for the effect of molar fraction of the mixed polymers , has been presented by introducing an adjustable parameter ( i α ) that fits the value of volume fraction ( i Φ ). The corrected interaction parameter values reflect the real image of the interaction between the different segments in the mixed polymers better than the previous approach of Ellis.