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Study on the Preparation and Properties of Polylactic
acid/Ethyl cellulose Blend Films
1
Shen Yiding﹡,Lai Xiaojuan,Wang Lei
College of chemistry and chemical engineering,Shaanxi University of Science & Technology,
Xi’an (710021)
E-mail:ydshen@sust.edu.cn
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.
1
The 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.