%0 Journal Article
%T Chitin Fiber and Chitosan 3D Composite Rods
%A Zhengke Wang
%A Qiaoling Hu
%A Lei Cai
%J International Journal of Polymer Science
%D 2010
%I Hindawi Publishing Corporation
%R 10.1155/2010/369759
%X Chitin fiber (CHF) and chitosan (CS) 3D composite rods with layer-by-layer structure were constructed by in situ precipitation method. CHF could not be dissolved in acetic acid aqueous solution, but CS could be dissolved due to the different deacetylation degree (D.D) between CHF and CS. CHF with undulate surfaces could be observed using SEM to demonstrate that the sufficiently rough surfaces and edges of the fiber could enhance the mechanical combining stress between fiber and matrix. XRD indicated that the crystallinity of CHF/CS composites decreased and CS crystal plane d-spacing of CHF/CS composites became larger than that of pure CS rod. TG analysis showed that mixing a little amount of CHF could enhance thermal stability of CS rod, but when the content of CHF was higher than the optimum amount, its thermal stability decreased. When 0.5% CHF was added into CS matrix, the bending strength and bending modulus of the composite rods arrived at 114.2£¿MPa and 5.2£¿GPa, respectively, increased by 23.6% and 26.8% compared with pure CS rods, indicating that CHF/CS composite rods could be a better candidate for bone fracture internal fixation. 1. Introduction Chitin, a natural polymer from marine resources [1], is found particularly in the shells of crustaceans such as crab and shrimp, the cuticles of insects, and the cell walls of fungi and is one of the most abundant biopolymers next to cellulose [2]. The shells contain 15%¨C40% chitin and its amount in the whole marine environment has been estimated at 1560 million tons [3, 4]. It has attracted more and more attention nowadays, due to its abundant resources, friendliness to the environment, and potential to substitute some petrochemicals [1]. Commercially, chitin is obtained at a relatively low cost from the wastes of the seafood processing industry. Briefly, the process consists of deproteinization of the raw shell material in a dilute NaOH solution and decalcification in a dilute HCl solution [5]. Chitosan (CS), a fully or partially deacetylated form of chitin, has become important materials in various fields, including medicine, biochemistry, analytical chemistry, and chemical engineering [6]. This derivative product with higher degree of deacetylation (D.D) results from the reaction of chitin with alkali (40%¨C45% NaOH solution) at elevated temperatures at prolonged exposures [5, 7]. Chitin and CS are polymers consisted of N-acetyl-glucosamine and N-glucosamine units randomly or block distributed throughout the biopolymer chain (Figure 1) [7, 8]. They are characterized by D.D; when D.D is lower than 50%,
%U http://www.hindawi.com/journals/ijps/2010/369759/