Fabrication Of Organic-Inorganic Nanocomposite Through A Novel In-situ Composite Hydrogels Method

The controlled growth of the nanosized mineral with respect to size, shape and crystal structure is a popular topic in modern material sciences. One of the potential ways is to synthesize minerals in polymeric solutions served as organic template for fabricating an organic-inorganic nanocomposite with different properties. So this research was very blooming in the past decades. Through the effective controls of polymers with abundant of functional groups, the mineral crystals with polymorphs and the composite with special performance were produced. These investigations accelerate the modern moterials progress.In the biomaterials field, researchers always looked for the inspirations from nature and explored different novel biomimetic/bio-inspired materials used as treatment and repair in clinic. With respect to the structure and characterization, there are many similarities between the master hydrogels and the tissue of body organs. Furthermore, the loading capability and penetrability of sensitive hydrogels are very excellent due to their particular interpenetrating network (IPN), so they were selected as drug delivery and biomineralizing matrix. So the study of the sensitive hydrogels and biomimeralization has attracted much attention, such as the collagen-hydroxyapatite membranes as tissue guided materials, poly(vinyl alcohol)-based hydrogels as artificial arthroses and ligaments, poly(vinyl alcohol)-hydroxyapatite composite hydrogels as artificial corneas, and so forth.In this work, we first investigated the structure, swelling behavior, pH sensitivity and thermal properties of poly(vinyl alcohol)-poly(acrylic acid) composite hydrogels synthesized via the radical polymerization of acrylic acid monomer in poly(vinyl alcohol) polymeric template and then chemical-physical cross-linking. Based on the investigation of the composite hydrogels, experimental parameters were modified and calcium/phosphate ions were introduced into the polymeric mixture for preparation the poly(vinyl alcohol)-poly(acrylic acid)-hydroxyapatite (PVA-PAA-HA) nanocomposites. The advantages of the aforementioned in-situ synthesized method included the size and shape of minerals could be altered, homogeneous distribution, excellent mechanical properties. The novel in-situ composite hydrogel method is a promising route applied in other research fileds.The structure and performance of the samples were chacracterized by Fourier-transformed Infrared (FTIR), X-ray diffractometer (XRD), Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), Transmission Electron Microscopy (TEM), mechanical testing, swelling behavior curve and so on. Above analyses focused on: (1) the effect of the functional groups of non-ionic poly(vinyl alcohol) and ionic poly(acryilic aicd) on the hydroxyapatite growth; (2) the structure and morphology of polymeric templates inside of the organic-inorganic composite; (3) the influence of poly(vinyl alcohol), poly(acrylic acid) and hydroxyapatite on the composites properties; (4) the mechanism of the organic network formation and hydroxyapatite mineralization, exhibition of the organic matrix configuration.The results indicated that the structure and performance of the organic-inorganic nanocomposite were improved through the novel in-situ composite hydrogel method. Porous organic-inorganic scaffold with interpenetrating network structure also could be produced via the novel method. After optimizing the experimental parameters, this novel in-situ composite hydrogel method will widely applied in other fields for fabrication fine nanocomposites.