Dissertation > Excellent graduate degree dissertation topics show

Preparation of Fast Responsive Sensitive Macroporous Hydrogels and Their Characterization

Author: XueYuHua
Tutor: ZhaoWenYuan
School: Ocean University of China
Course: Materials Physics and Chemistry
Keywords: Sensitive hydrogels Sodium chloride (NaCl) Phase separation Holes Swelling ratio Response rate
CLC: O648.17
Type: Master's thesis
Year: 2010
Downloads: 132
Quote: 0
Read: Download Dissertation

Abstract

Sensitive hydrogels for its excellent hydrophilic and sustained release performance are widely used in industrial and agricultural production and bio-pharmaceutical field, the current research focus. Wherein the most studied is the pH and the temperature-sensitive hydrogel, because only easy control of pH and temperature, and is physiological, biological and chemical systems are two very important factors. Since the conventional hydrogel some disadvantages (such as response rate is slow, and poor mechanical properties), and thus greatly limits the application of the hydrogel, thus improving the response rate of the hydrogel becomes the current research and development of the polymer gel is an important The issue, and the most common is the preparation of the macroporous gel. By phase separation to prepare a macroporous hydrogel is a more effective method, particularly for the temperature-sensitive hydrogel, and the use of this method of the pH-sensitive hydrogel Investigator rarely. In this paper, the method of phase separation has prepared three different sensitivity of the system macroporous hydrogel to improve the response rate of the hydrogel. First prepared with different concentrations of aqueous sodium chloride solution as the polymerization medium, a typical pH sensitivity of polyacrylic acid (PAAc) macroporous hydrogel study its various properties, on this basis, in order to expand the acrylic in the hydrogel succession prepared pH-sensitive poly (acrylic acid-co-acrylamide) [P (AAc-co-AM)] macroporous hydrogel as well as pH and temperature dual sensitivity poly ( N-isopropyl acrylamide-co-acrylic acid) [P (NIPA-co-AAC)] macroporous hydrogel. Discusses the the macroporous hydrogel formation mechanism of their chemical composition and structure were determined by infrared spectroscopy (FT-IR), and their microscopic morphology was observed with a scanning microscope (SEM), and by the swelling ratio of these hydrogel measuring and comparing the performance (including the pH sensitivity, temperature sensitivity, sensitivity to ionic strength, the swelling kinetics and to the swelling kinetics, etc.) using different concentrations of aqueous sodium chloride solution prepared in the swelling of the gel. System found by: (1) NaCl aqueous solution as a polymerization medium, and their different concentrations does not affect a system of chemical composition and structure of the obtained gel; (2) P (NIPA-co-AAc) hydrogel in the polymerization phase separation occurs during the significant morphology changes, i.e. to change from a transparent to an opaque white, even after purification, the changes in the morphology of the gel; PAAc with P (AAc-co-AM) of these two hydrogel The gum did not appear such morphology changes; different (3) of NaCl concentration of the polymerization medium, resulting in the gel phase separation there are significant differences in the degree of polymerization and cross-linking process; when the NaCl concentration of the polymerization medium is not a small 0.3mol / L, the gel during the polymerization process before significant phase separation occurs, the synthesis gel before having a pore network structure; continue to increase as the polymerization medium in the concentration of NaCl, its synthetic gel contains holes network The structure is more and more, and increasingly large; (4) As the polymerization medium NaCl concentration increased, the synthesis of the gel in distilled water having a higher SRE, and demonstrate a strong pH, temperature and ion intensity sensitivity and faster to swelling and the swelling rate; (5) P (NIPA-co-AAc) hydrogel, AAc the introduction can significantly improve its phase transition temperature, and broaden its phase transition interval ; (6) P (NIPA-co-AAc) dry gel appeared during swelling in distilled phenomenon of swelling inflection, i.e. the first slow swelling, and then accelerated swelling; PAAc with P (AAc-co-AM) Two hydrogel, but does not appear this phenomenon; (7) Since the the the macroporous hydrogels have the advantages of fast response rate, the synthesis of these three large holes sensitive hydrogel is expected in biological fields such as drug control The release has been widely used.

Related Dissertations

CLC: > Mathematical sciences and chemical > Chemistry > Physical Chemistry ( theoretical chemistry ),chemical physics > Colloid chemistry ( physical and chemical dispersion system ) > Colloid > Gel and soft
© 2012 www.DissertationTopic.Net Mobile