Oxidized starch films reinforced with natural halloysite
- PDF / 619,516 Bytes
- 7 Pages / 584.957 x 782.986 pts Page_size
- 12 Downloads / 230 Views
idized starch (OSt) films reinforced with natural halloysite were prepared by adding modified natural halloysite nanotubes into an OSt matrix. The halloysite/OSt films were characterized by x-ray diffraction, scanning electron microscopy, and ultraviolet spectrometry. The mechanical properties and moisture absorbability of the films were also studied. The modified halloysite nanotubes were well distributed in the starch matrix, and the tensile strength (TS) of the films was greatly enhanced, but the moisture adsorption ability of the films only changed slightly. The flexibility of the films was improved by adding glycerol but at a cost of reducing the TS. Incorporating a small amount of poly(vinyl alcohol) (PVA) improved both the TS and the percent elongation at break of the halloysite/OSt films.
I. INTRODUCTION
Plastics are one of the most commonly used materials and provide great convenience for us in our daily lives. Poly (lactic acid) and poly (lactic-co-glycolic acid) are two common biopolymers and have been widely used as biomaterials in clinical rehabilitative medicine. Since they are expensive, it is desirable to find renewable cheap and environmentally benign materials to use as common plastics.1 Starch is one of the most promising biopolymers and has attracted worldwide attention because of its abundance, nontoxicity, biodegradability, and low cost.2 Starch films, as packing materials, have been prepared from many different starch sources.3,4 Oxidized starch (OSt) is widely used in industries such as paper, textile, and laundry finishing. It also shows great potential in making films because of its low viscosity, excellent film forming ability, and transparency. But because of its poor mechanical properties and high moisture sensitivity, starch films often fail to meet the demands of many applications. Several methods have been used to overcome these drawbacks, including modification of the starch or blending it with other materials.5–7 Biocompatible synthetic polymers such as poly(vinyl alcohol) (PVA), ethylene vinyl acetate copolymer, poly(e-caprolactone), and Bionolle have been incorporated into starch to improve its properties.8 But to maintain its biodegradability, natural polymers such as chitosan,9 cellulose nanofibers,10 alginate,11 pullulan,12 gelatin,13 or other proteins14,15 are more suitable. These can be selected to improve the mechan-
Address all correspondence to these authors. a) e-mail: [email protected] b) e-mail: [email protected] DOI: 10.1557/jmr.2011.359 2938
J. Mater. Res., Vol. 26, No. 23, Dec 14, 2011
http://journals.cambridge.org
Downloaded: 12 Oct 2014
ical and other properties of the starch films. In addition to organic materials, inorganic materials have also been incorporated into starch films. Reis and coworkers16 prepared starch thermoplastic/hydroxyapatite composites and studied the possibility of using them as a bone material. Clay is another important inorganic filler, and it is often used to make clay-reinforced synthetic polymers. Starch films with montmorillonite nanoparticles disp
Data Loading...
