Interaction of Microstructure and Interfacial Adhesion on Impact Performance of Polylactide (PLA) Ternary Blends

Abstract

Polyactide (PLA) was blended with an ethylene/n-butyl acrylate/glycidyl methacrylate (EBA-GMA) terpolymer and a zinc ionomer of ethylene/methacrylic acid (EMAA-Zn) copolymer. The phase morphology of the resulting ternary blends and its relationship with impact behaviors were studied systematically. Dynamic vulcanization of EBA-GMA in the presence of EMAA-Zn was investigated by torque rheology, and its cross-link level was evaluated by dynamic mechanical analysis. Reactive compatibilization between PLA and EBA-GMA was studied using Fourier transform infrared spectroscopy. The dispersed domains in the ternary blends displayed a “salami”-like phase structure, in which the EMAA-Zn phase evolved from occluded subinclusions into continuous phase with decrease in the EBA-GMA/EMAA-Zn ratio. An optimum range of particle sizes of the dispersed domains for high impact toughness was identified. Also, the micromechanical deformation process of these ternary blends was also investigated by observation of the impact-fractured surfaces using the electron microscope. It was suggested that the low cavitation resistance of dispersed particles in conjunction with suitable interfacial adhesion was responsible for the optimum impact toughness observed.

Selective localization of titanium dioxide nanoparticles at the interface and its effect on the impact toughness of poly(L-lactide)/poly(ether)urethane blends

“…For each measurement, about 5 mg of the sample was directly heated from 0 to 200°C at a heating rate of 10°C/min. The value of were determined using the most commonly used Equation (3) [21,22,41]: (3) where "H m and "H c are the enthalpies of melting and cold crystallization, respectively; w f is the weight percent of the PLLA matrix, and "H m 0 is the melting enthalpy of completely crystalline PLLA (93.7 J/g [42]). …”

Fully bio-based, highly toughened and heat-resistant poly(L-lactide) ternary blends via dynamic vulcanization with poly(D-lactide) and unsaturated bioelastomer

“…Therefore, specific compatibilization is required to fine-tune the morphology and enhance the interfacial adhesion between PLLA and the blending partners [17,18]. Dynamic vulcanization, involving selective crosslinking of rubber polymer during melt blending with a thermoplastic polymer, has been demonstrated to be a powerful technique to control the morphology, enhance interfacial adhesion, and improve the final properties of PLLA blends with elastic polymers [19][20][21][22][23]. Some supertough PLLA blends with impact strengths of more than 530 J m −1 (or 53 kJ m −2 ) have been achieved by dynamic vulcanization of PLLA with some elastic polymers [22,[24][25][26][27][28].…”

“…Some supertough PLLA blends with impact strengths of more than 530 J m −1 (or 53 kJ m −2 ) have been achieved by dynamic vulcanization of PLLA with some elastic polymers [22,[24][25][26][27][28]. It is worth noting that the sustainability of PLLA was compromised since most elastic polymers in previous studies were prepared from non-renewable feedstocks [19,25,28,29]. In this sense, some sustainable elastomers such as natural rubber, epoxidized natural rubber, and bioelastomer have gained much attention in fabricating fully sustainable supertough PLLA via dynamic vulcanization [22,24,30,31].…”

Highly toughened polylactide with novel sliding graft copolymer by in situ reactive compatibilization, crosslinking and chain extension

“…They considered a ternary blend system consisting of PLA, an epoxy-containing elastomer (EBA-GMA), and a zinc ionomer (EMAA-Zn). 25 The zinc ions catalyzed the in situ crosslinking of the epoxy-containing elastomer and also promoted the reactive compatibilization at the interface of PLA and the elastomer, resulting in the excellent impact strength of PLA.…”