Study On PMMA Based Nanocomposites As Denture Base Material

Poly(methyl methacrylate)(PMMA) is an important member in the family of poly(acrylic ester)s and widely used in plastics products in many areas due to its excellent physical and chemical properties. PMMA prepared by suspension polymerization is widely used as dental materials such as denture base powder and denture powder, but it doesn't yet satisfy the requirement of the dental materials completely because of the low flexural strength, low surface hardness and poor abradability. How to improve these properties becomes the research focus.In this paper, PMMA nanocomposites were prepared via in situ suspension polymerization. Nano-SiO₂, Nano-TiO₂ and montmorillonite(MMT) need to be modified to make them homogeneous disperse in the monomer MMA. The modified inorganic particles were characterized with Fourier transform infrared spectroscopy (FI-IR), thermal gravimetric analysis (TGA), transmission electron microscopy (TEM) and X-ray diffraction(XRD). It shows that MMT and the surface of nano-SiO₂ and nano-TiO₂ had been well modified .The microstructure of nanocomposites was characterized with TEM, XRD. The influence of the three inogarnic particles on molecular weight of PMMA, the shape and size of the the nanocomposite microsphere, the mechanical, thermal properties and the biological safety of the composites were investigated.The results indicate that, PMMA nanocomposites with modified SiO₂, TiO₂ and MMT could be successfully prepared via suspension polymerization. The presence of inorganic particles and the content influenced the molecular weight of PMMA and the shape and size of nanocomposite mricosphere. The modified inorganic particles could improve mechanical and thermal properties. The biological experiments proved that the PMMA/MMT nanocomposite was safe as dental material.