Influence of Multiwalled Carbon Nanotubes on Biodegradable Poly(lactic acid) Nanocomposites for Electroactive Shape Memory Actuator RAJA MOHAN School of Engineering and Technology, Jagran Lakecity University, Mugaliyachap, Bhopal 462 044, India J. SUBHA Central Institute of Plastic Engineering & Technology, Govindpura, Bhopal 462 044, India JAVED ALAM King Abdullah Institute for Nanotechnology, King Saud University, P. O. Box 2455, Riyadh 11451, Saudi Arabia Correspondence to: Raja Mohan; e-mail: drmraja@jlu.edu.in. Received: November 19, 2015 Accepted: December 25, 2015 ABSTRACT: Poly(lactic acid)/epoxidized soybean oil/carbon nanotubes (PLA/ESO/CNTs) nanocomposites were prepared by the solution blending process, and the influence of ESO on the properties of the composites was studied. Differential scanning calorimetry and X-ray diffraction revealed that the addition of CNTs improved the crystallinity of the nanocomposites. The modulus increased with the addition of CNTs content in the composites. Morphological characterizations were done by scanning electron microscopy and transmission electron microscopy. Electrical conductivity of PLA/ESO/CNT composites increased with the addition of CNTs. This study revealed that the addition of ESO facilitated the dispersion of the CNTs in the PLA matrix. C  2016 Wiley Periodicals, Inc. Adv Polym Technol 2016, 00, 21664; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21664 KEY WORDS: Biopolymers, Differential scanning calorimetry (DSC), Nanocomposites, Stimuli-sensitive polymers, TEM Introduction P oly(lactic acid) (PLA) is a biodegradable aliphatic polyester derived from lactic acid, which can be obtained from the fermentation of renewable resources. It has received considerable attention as a promising environmentally friendly material suitable for replacing commodity polymers, particu- larly in disposable packaging applications. 1–3 In spite of many attractive properties of PLA such as high strength, high modu- lus, biodegradability, and processability, its engineering appli- cations have been limited due to its brittleness and high price. Considerable efforts have been conducted to modify the proper- ties of PLA. Blending of PLA with other polymers such as poly- caprolactone, polybutylene succinate, or polyetherurethane has Contract grant sponsor: National Plan for Science, Technology and Innovation (MAARIFAH), King Abdulaziz City for Science and Technology, Kingdom of Saudi Arabia. Contract grant number: 11-NAN-1486-02. ment of the flexibility could also be achieved by blending it with low-molecular-weight plasticizers such as citrate esters, polyethylene glycol, polypropylene glycol, and oligomeric lac- tic acid. 9–16 Epoxidized soybean oil (ESO) is used as a plasticizer for PLA by increasing the elongation at break of the polymer and as well as depressing the glass transition temperature of the plasticized PLA. Carbon nanotubes (CNTs) have received much attention because of their fascinating properties, such as high modulus and high electrical/thermal conductivity. 17,18 It has been reported that maleic anhydride-grafted multiwalled carbon nanotubes (MA-g-MWCNTs) were generated by chemical and physical bonding with the PLA matrix and therefore increased the interfacial bonding between CNTs and the PLA matrix. 19 The technology of surface-initiated ring opening polymeriza- tion was also done to obtain CNT-graft-poly(L-lactide). Through this method, the dispersion of CNT was optimized and it also enhanced the interfacial bonding between the polymer chains and CNTs. 20 Few other studies were also conducted by graft- ing CNTs and PLA with polyhedral oligomeric silsesquioxane 21 and also cross-linked CNTs and PLA by a water cross-linking reaction. 22 Advances in Polymer Technology, Vol. 00, No. 0, 2016, DOI 10.1002/adv.21664 C  2016 Wiley Periodicals, Inc. 21664 (1 of 6) FATHILAH BINTI ALI Department of Biotechnology Engineering, Kuliyyah of Engineering International Islamic University Malaysia (IIUM), Jalan Gombak 53100 Kuala Lumpur, Malaysia [Correction added on May 9, 2016 after first online publication on January 27, 2016: Fathilah Binti Ali has been added as the last author to the author's list.] been attempted to improve the flexibility of PLA. 4–8 Enhance-