Study on the Preparation and Properties of Polylactic acidEthyl cellulose Blend Films

Poly(lactic acid)/ethyl cellulose composite films(PLA-EC) were prepared by a casting method when using n-alkenyl succinic anhydride(ASA) as a novel plasticizer and chloroform as co-solvent. Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction

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Study on the Preparation and Properties of Polylactic

acid/Ethyl cellulose Blend Films1

Shen Yiding﹡，Lai Xiaojuan，Wang Lei

College of chemistry and chemical engineering，Shaanxi University of Science & Technology，

Xi’an （710021）

E-mail：

Abstract

Poly(lactic acid)/ethyl cellulose composite films(PLA-EC) were prepared by a casting method when using n-alkenyl succinic anhydride(ASA) as a novel plasticizer and chloroform as co-solvent. Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction (XRD) and scanning electron microscope(SEM) were used to analyze the morphological properties of the composite films. Mechanical properties and water absorption of the cast composite films were also measured. FT-IR indicates there are some strong interaction and good compatibility in composite films. XRD shows that both EC and PLA lost crystallinity after being plasticized, and the PLA/EC composite films plasticized with n-ASA result in a markedly enhanced coalescence of the two polymers. n-ASA is proved to be an ideal plasticizer for EC based films after testing mechanical properties. The PLA resin has a reinforcing effect on PLA/EC composite films when w(PLA) ≤37%. Water absorption decreases with increasing ASA content while it increases with increasing PLA content in the PLA/EC composite films. The composite films can be used as a new kind of drug delivery material with the wide application prospect. Keywords：Poly(lactic acid)；Ethyl cellulose；n-alkenyl succinic anhydride；Composite film

1 Introduction

Poly(lactic acid) (PLA) is well known for its highly biocompatible and biodegradable character and has been widely investigated for application in medical and pharmaceutical devices for controlled release of drugs [1,2]. Ethyl cellulose (EC) is probably the most widely used and broadly studied film-forming polymer in coated controlled release solid dosage forms. However, plain EC films are brittle and the behavior of plain EC is like behavior of glass, which is a disadvantage of film for controlled release of drug. Therefore, addition of other components is essential to enhance film-forming characteristic, workability and serviceability of the coatings[3].

In the present study, composite films of poly(lactic acid) (PLA) and ethylcellulose (EC) with various compositions were prepared. Thereinto, ethyl cellulose is used as a primary component of the film and poly(lactic acid) is used for adjusting release of drugs. In polymeric solutions, plasticizers increase the free volume between the polymer chains by reducing the number of active centers available for rigid polymer–polymer contacts. The composite films of PLA and EC were obtained successfully using n-alkenyl succinic anhydride(ASA) as a novel plasticizer and chloroform as co-solvent for PLA and EC. Both PLA and EC have been widely used in a variety of medical applications and, to our knowledge, there has not been a systematic investigation of the mechanical properties of these blends. we investigated the structural and mechanical properties of PLA-EC composite films by Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction (XRD) and scanning electron microscope(SEM) and so on. The films may be used as a potential material for controlled release of drugs with good application foreground. 1The authors are thankful to the National Natural Science Foundation of China (grant number: 20576067) and the Ph.D. Programs Foundation of Ministry of Education of China under grant No. 20050708004 for financial support.

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