Poly(lactic acid)/(styrene‐ethylene‐butylene‐styrene)‐g‐maleic anhydride copolymer/sepiolite nanocomposites: Investigation of thermo‐mechanical and morphological properties

Abstract

In this study, sepiolite nanoclay is used as reinforcing agent for poly(lactic acid) (PLA)/(styreneethylene-butylene-styrene)-g-maleic anhydride copolymer (SEBS-g-MA) 90/10 (w/w) blend.Effects of sepiolite on thermal behavior, morphology, and thermomechanical properties of PLA/SEBS-g-MA blend were investigated. Differential scanning calorimetry results showed 7% improvement in crystallinity at 0.5 wt% of sepiolite. The nanocomposite exhibited approximately 36% increase in the tensile modulus and 17% increase in toughness as compared with the blend matrix at 0.5 and 2.5 wt% of sepiolite respectively. Field emission scanning electron microscopy and transmission electron microscopy images exhibited sepiolite-induced morphological changes and dispersion of sepiolite in both PLA and SEBS-g-MA phases. Dynamic mechanical analysis and wide angle X-ray diffraction present evidences in support of the reinforcing nature of sepiolite and phase interaction between the filler and the matrix. This study confirms that sepiolite can improve tensile modulus and toughness of PLA/SEBS-g-MA blend. Biobased polymers have received a great deal of attention because they minimize the use of petrochemical resources and are superior in eco-friendliness. 1 The poly(lactic acid) (PLA) is a biodegradable polyester with high tensile strength and modulus. However, because of its brittleness, low thermal stability, and tensile toughness, neat PLA is limited in applications. Properly modified PLA can be used in many applications like food packaging, textile, electronics, surgical sutures, drug delivery systems, and transport and building. [2][3][4][5] Techniques such as plasticization, copolymerization, and blending are used to deal with the drawbacks of PLA. Blending is a feasible option compared with other techniques because of its cost effectiveness and minimum trade-off in properties. Blending with a thermoplastic elastomer like SEBS can be an effective way to toughen PLA. The SEBS is widely used in commercial applications such as sealants, footwear, coatings, 6 automotive parts, adhesives, temperature sensors, 7 and wire insulation. Sangeetha et al 8 reported that impact strength was higher in PLA/SEBS-g-MA blends than that in PLA/SEBS, which may be due to the interaction between maleic anhydride groups in SEBS-g-MA and carbonyl groups of PLA. SEBS-g-MA copolymer is used to toughen many polymers such as polypropylene (PP), 9 high density polyethylene, 10 nylon-6, 11 nylon-6,6 12 and PLA. 8,[13][14][15] reported that SEBS-g-MA is an effective impact modifier for PP/PLA blends. However, tensile modulus and strength decreased.Various kinds of fillers such as organo-modified montmorillonite (OMMT), [16][17][18][19] carbon nanotubes (CNTs), 20-22 calcium carbonate, [23][24][25] silica, 26-28 and carbon fullerenes 29,30 are used to enhance the thermomechanical properties of PLA. Although, OMMTs and carbon nanotubes worked well with PLA, the formers need special organic treatments to get exfoliated, while the latters are expensive and are detrimen...

Effects of halloysite nanotube on the performance of natural fiber filled poly(lactic acid) composites

“…In addition, the degree of crystallinity ( X c ) gradually decreases with increase the loading of HNT due to the physical presence of rigid clay, which disturbs crystalline orientation of PLA chains on account of enhanced surface adsorption interaction with PLA. Similar tendency has been reported in the literature . On the other hand, at 2 phr loading of HNT in PLA matrix, the improvement of crystallinity of the PLA‐HNT composites is by 16% with the addition of MA‐g‐PLA (Table ).…”

“…This can be attributed to the fact that MA‐g‐PLA is able to promote better dispersibility of HNT in the PLA matrix, which subsequently increases the nucleating effect of HNT. Similar observation has been also reported in the literature …”

ZnO nanoparticles as chain elasticity reducer and structural elasticity enhancer: Correlating the degradating role and localization of ZnO with the morphological and mechanical properties of PLA/PP/ZnO nanocomposite

“…Today, the development and production of biodegradable plastics is one of the appropriate ways to control or reduce the accumulation of nonbiodegradable plastics to preserve the limited resources of fossil fuels and also to reduce the ecosystem destruction. [1][2][3][4][5][6] Because of its biocompatibility and inherent biodegradability, polylactic acid (PLA) is one of the most important prominent biodegradable biopolymers that has found extensive applications in the various medical, packaging, and textile industries. 7,8 The main drawback of this polymer returns to its brittleness, which diminishes its widespread application.…”

A comparative study on the effect of different reactive compatibilizers on injection‐molded pieces of bio‐based high‐density polyethylene/polylactide blends

“…These tailor-made copolymers can reduce particle size, increase morphological stability and interfacial adhesion, and improve final mechanical properties. 23 Some copolymers have been specifically designed for PLA 24,25 or PE, 22,26 providing good results as compatibilizers. 27 The second method to improve the compatibility in polymer blends is the use of in situ (reactive) compatibilization, the so-called reactive extrusion (REX), during the compounding of the polymer formulation.…”