Interactions, structure and properties in poly(lactic acid)/thermoplastic polymer blends

Abstract

Abstract. Blends were prepared from poly(lactic acid) (PLA) and three thermoplastics, polystyrene (PS), polycarbonate (PC) and poly(methyl methacrylate) (PMMA). Rheological and mechanical properties, structure and component interactions were determined by various methods. The results showed that the structure and properties of the blends cover a relatively wide range. All three blends have heterogeneous structure, but the size of the dispersed particles differs by an order of magnitude indicating dissimilar interactions for the corresponding pairs. Properties change accordingly, the blend containing the smallest dispersed particles has the largest tensile strength, while PLA/PS blends with the coarsest structure have the smallest. The latter blends are also very brittle. Component interactions were estimated by four different methods, the determination of the size of the dispersed particles, the calculation of the Flory-Huggins interaction parameter from solvent absorption, from solubility parameters, and by the quantitative evaluation of the composition dependence of tensile strength. All approaches led to the same result indicating strong interaction for the PLA/PMMA pair and weak for PLA and PS. A general correlation was established between interactions and the mechanical properties of the blends.

Physical and Degradation Properties of Polylactic Acid and Thermoplastic Starch Blends – Effect of Citric Acid Treatment on Starch Structures

“…The large size of TPS granules showed that untreated TPS had failed to improve the interfacial interaction between the hydrophobic PLA and the hydrophilic TPS, thus producing immiscible blends of PLA/TPS blends. Imre et al (2014) reported that a heterogeneous structure from immiscible blends could weaken the interaction between the blends in the system. Thus, a large phase separation could be seen in the SEM micrograph.…”

“…It also had good stiffness and strength (Imre et al 2014). However, PLA has some drawbacks, such as brittleness, moisture problems, and, most importantly, it is produced at a relatively high price (Acton 2013;Imre et al 2014). To reduce these undesirable properties of PLA, researchers have attempted to modify the PLA in many ways, such as by plasticization, copolymerization, blending, and composite production, to enhance its properties and, most importantly, to lower the cost of producing the PLA itself (Auras et al 2011).…”

“…PLA can be recyclable and compostable. It also had good stiffness and strength (Imre et al 2014). However, PLA has some drawbacks, such as brittleness, moisture problems, and, most importantly, it is produced at a relatively high price (Acton 2013;Imre et al 2014).…”

Toughness Improvement in Ternary HDPE/PS/PET Polymer Blends with Compatibilizer

“…The most influential factors, during the formation of the microstructure, are the compositional ratio, the viscosity and the interfacial bond between the phases [10]. By combining the effects of these factors, different complex morphological structures can be formed, e.g.…”

Investigation of compatibilization effects of SEBS-g-MA on polystyrene/polyethylene blend with a novel separation method in melted state

“…In case of preparing polymer blends, the final morphology strongly depends on droplet breakup and coalescence processes during shear flow [7]. These two forces both dominate under transient condition, and their balance in steady state was described by Taylor's theory of Capillary number [8,9].…”