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Mechanical properties of poly(lactid acid) plasticized by cardanol derivatives

Greco, Antonio, Ferrari, Francesca, Maffezzoli, Alfonso
Polymer degradation and stability 2019 v.159 pp. 199-204
acetates, crystal structure, crystallization, equations, glass transition temperature, mechanical properties, modulus of elasticity, plasticizers, polylactic acid
This work is aimed to study the effect of cardanol derived plasticizers on the tensile modulus of poly(lactic acid), PLA. Neat cardanol, cardanol acetate (CA), and epoxidized cardanol acetate (ECA) were used, at contents ranging between 10% and 30%. For comparison purposes, another green plasticizer, poly(ethylene glycole) (PEG), was used. Tensile tests were carried out to evaluate the influence of the type and the amount of plasticizer on the tensile modulus of injection molded PLA. Within the examined composition limits, PLA plasticized by cardanol derivatives showed lower modulus than PEG plasticized PLA. The tensile modulus of plasticized PLA was correlated to the evolution of glass transition temperature and degree of crystallinity. At low plasticizers content, the modulus of PLA decreased as the glass transition temperature decreased, due to a better miscibility of the plasticizer with PLA. The opposite occurred at high plasticizer content; in this case, the higher modulus found for more compatible plasticizers were attributed to an increased crystallization kinetic. The evolution of elastic modulus as a function of glass transition temperature and degree of crystallinity was analyzed using a single equation capable to fit the data obtained using different plasticizers.