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Study on the Preparation, Structure and Properties of Starch Based Medical Sponge

Author: HuQin
Tutor: MaJingHong
School: Donghua University
Course: Materials Science
Keywords: Medical sponge Starch Freeze-drying method Gelatinization Graft copolymerization
CLC: TS231
Type: Master's thesis
Year: 2010
Downloads: 262
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Abstract


Natural polymer prepared porous absorbable sponge in wound dressings, drug release, cell culture and tissue engineering has shown promising applications in recent years by the widespread concern. Medical sponges used for this purpose should have a larger pore surface area can be completely degraded, and capable of being absorbed by the body. Starch as one of nature's most abundant natural polymer, is an ideal preparation for medical sponge material has good biocompatibility, non-toxic and non-allergic reactions advantages. The preparation of porous medical sponge There are many methods, wherein one of the freeze-drying method is the easiest and most application value, can not use any organic reagent under the conditions of preparation of a porous sponge. In this thesis, the original starch gelatinization and graft modified, then gelatinized starch sponge and grafted starch sponge was prepared by freeze-drying, the sponge structure, morphology and performance characterization and study the process of freeze-drying different pre-freezing conditions on the the the sponge forming and pore structure of impact. The main findings are summarized as follows: (1) Starch Medical sponge was prepared by freeze-drying method to study the main factors affecting the structure and properties of the sponge. Found starch a subject gelatinized modified to get a porous medical sponge, and gelatinized starch is a starch molecule between interconnected, winding a three-dimensional network structure is formed, the aqueous colloid of the mesh, and its internal, has good The pore structure. In the freeze-drying process, the the colloid liquid water into solid ice, and then in the high vacuum environment, the ice sublimates directly into water vapor, is withdrawn from the system, thereby forming a three-dimensional network structure of the porous sponge. Gelatinized modified starch prepared sponge showing a good water absorbency, water absorption rate, and mechanical properties. (2) a detailed study of the freeze-drying conditions pre-frozen sponge structure and morphology was found: the freezing conditions have a great impact on the the sponge holes in the structure. With the decrease of the pre-freezing temperature, the pore size of the sponge is also reduced; addition, the structure of the different parts of the holes in the sponge was characterized by scanning electron microscopy, and found that the size of the holes, the orientation, and uniformity are governed by the mode of heat transfer a significant impact . Can be adjusted by controlling the heat transfer structure and morphology of the holes in the sponge. (3) introduced in the starch molecular chain by a graft copolymerization method hydrophilic polyacrylamide and polyacrylic acid, and the gelatinized starch to be further modified. The chemical structure of the grafted starch characterized by IR and NMR. Grafted starch were freeze-dried to prepare a sponge and grafted starch composition forming performance, physical and mechanical properties and water absorption sponge. The results showed that: compared with the gelatinized starch sponge, grafted starch sponge absorbent rate, high absorbency, excellent mechanical properties, its performance is further improved compared with the gelatinized starch sponge. (4) The paper also starch / poly (N-isopropyl acrylamide) (PNIPAAm) composite sponge preparation and preliminary study of the starch film. The observation of the scanning electron microscope showed that the starch / PNIPAAm composite sponge with interconnected pore structure, which greatly improve its water absorption. In the same time, the introduction of the heat-sensitive poly (N-isopropyl acrylamide), the composite sponge has a certain degree of temperature sensitivity. In addition, the paper also explore different methods for the preparation of the starch film and found that the slow drying in the air can be prepared with good transparency and flexibility of the starch film.

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CLC: > Industrial Technology > Light industry,handicrafts > Food Industry > Starch Industry > Basic theory
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