Comparison Between Different Syntesis Methods of PMMA/HA Using Ultrasonic Radiation

Abstract

Summary: The use of PMMA as dental and osseous cement and also in the fabrication of intraocular lenses has been widely reported. The combination of its excellent properties with those of hydroxyapatite (HA) to form a composite material, can result in very interesting properties as a biomaterial. The key is to obtain a good filler dispersion and interface bonding. Ultrasonic radiation seems to be a very versatile method for the synthesis of these materials, since the use of conventional initiators can be avoided, the filler dispersion improved and the interface interaction can be promoted. In the present work PMMA/HA composite materials were prepared by three different synthesis routes using ultrasonic radiation, in order to study the effect of the synthesis method on the final microstructure. Method I: in situ synthesis of PMMA and HA, under ultrasonic radiation by emulsion polymerization of MMA and HA precursors. Method II: in situ synthesis of HA, (from its precursors) by high frequency ultrasound in commercial PMMA solution Method III: in situ polymerization of MMA under high frequency ultrasonic radiation and adding HA to the solution and Method IV Mixing of hydroxyapatite nanocrystals, in different proportions, in a solution of commercial PMMA, by different periods from 10 min to 7 h, under low frequency (conventional) ultrasonic radiation, to compare the effect of high frequency and conventional ultrasound radiation. The different materials were characterized by FTIR, SEM, TEM, DRX, 1H NMR and TGA. The results showed that, all the composites prepared by in situ synthesis showed an interaction between HA and PMMA, manifested by a bonding of the phosphate groups with the polar groups of the polymer matrix observed by FTIR. On the other hand, when the synthesis was carried out simultaneously adding HA and PMMA precursors a inhibition of the polymerization reaction of MMA was observed.

Comparative Kinetic Study and Microwaves Non-Thermal Effects on the Formation of Poly(amic acid) 4,4′-(Hexafluoroisopropylidene)diphthalic Anhydride (6FDA) and 4,4′-(Hexafluoroisopropylidene)bis(p-phenyleneoxy)dianiline (BAPHF). Reaction Activated by Microwave, Ultrasound and Conventional Heating

“…A yield of 87% was reached with 90 min of sonication time, sample U709, if we compare this yield value with the value obtained in the same reaction conditions of temperature (70 °C) and time for sample synthesized by microwave irradiation, sample M709, just a slight difference of 4% was observed. The high yield observed under US conditions can be explained by effective acoustic cavitation, ultrasound comprises sonic waves with frequencies in the range of 0.001 to 107 MHz, when these waves are transmitted through a liquid cavitation takes place [ 37 ], it can be defined as the growth and violent collapse of micrometer-sized bubbles. The collapse of these bubbles generates extreme conditions within the core of the bubble, resulting in very high temperatures and pressures, which provide enough energy for polycondensation reaction; very efficient mixing and formation of liquid jets can also occur, due to the rapid motion of fluid [ 38 ].…”

Effect of barium-coated halloysite nanotube addition on the cytocompatibility, mechanical and contrast properties of poly(methyl methacrylate) cement

“… 14 , 15 A major focus has been on the inclusion and testing of various additives or fillers designed to improve or remediate the mechanical, thermal and biological deficiencies in conventional PMMA. 16 , 17 Researchers have studied combinations of PMMA bone cement and several micro- and nanoparticles, including barium sulfate, 18 carbon nanotubes, 19 , 20 chitosan, 21 collagen, 22 clays, 23 , 24 hydroxyapatite, 25 , 26 magnesium oxide, 27 silica 28 , 29 and silver nanoparticles 30 (refer the study by Lewis 17 for an extensive review of these, and other additives, and their effects on PMMA).…”