Influence of CIG

Vol. 123 (2013) ACTA PHYSICA POLONICA A No. 2
Proceedings of the 2nd International Congress APMAS2012, April 2629, 2012, Antalya, Turkey
Inuence of Commercial Inert Glass Addition
on the Mechanical Properties
of Commercial Synthetic Hydroxyapatite
N. Demirkola;b, F. Nuzhet Oktarc and E. Sabri Kayalib
aTechnical Prog. Dept., Vocational School of Degirmendere Ali Ozbay, Kocaeli University, Golcuk, Turkey
bMetallurgical and Materials Engineering Dept., Istanbul Technical University, Istanbul, Turkey
cMedical Imaging Techniques Dept., School of Health Related Professions, Marmara University, Istanbul, Turkey
In this study, microstructures and mechanical properties of commercial synthetic hydroxyapatite (CSHA)
commercial inert glass (CIG) composites were investigated. The goal of development of CSHACIG composite
is to improve mechanical properties of hydroxyapatite. For this reason, CSHA powders were mixed with 5 and
10 wt% CIG separately. Pressed samples were sintered at the dierent temperatures in the range of 10001300C.
The physical and mechanical properties were determined by measuring density, compression strength, the Vickers
microhardness. Structural characterization was carried out with X-ray diraction and scanning electron microscopy
studies. The experimental results were discussed to determine optimum amount of reinforcement material and the
eect of sintering temperature on the microstructure and the mechanical properties of CSHACIG composites. The
mechanical properties of composites decreased with increasing CIG content. The highest mechanical properties
and the highest density were obtained in CSHA5 wt%CIG composite sintered at 1300C.
DOI: 10.12693/APhysPolA.123.427
PACS: 81.05.Je
1. Introduction
Hydroxyapatite (HA) is one of most important market
valued candidate biomaterial which is still in use
since decades in medicine and dentistry applications. HA
with chemical formula (Ca10(PO4)6(OH)2), assembling
the main mineral components of bones and teeth, is
among the leading biomaterials satisfying these requirements
[1]. Synthetic HA has excellent biocompatibility
due to its chemical stability with the mineral portions
of hard tissues as well as its ability to constitute chemical
bonding with surrounding tissues [2]. But still HA
as a bulk material is not suitable for loaded situations
due to its very brittle character [3]. For this reason, the
main weakness of this material lies in its poor mechanical
strength which makes it unsuitable for load-bearing
applications [4, 5]. HA material must be reinforced with
other materials to form a durable and more load resistible
composite. For this reason, HA bioceramics are reinforced
with other ceramics or metals in the form of powders,
platelets, or bers belonging to this type of material.
Addition of second-phase ceramic materials (e.g.,
zirconia, titania, or alumina) to the HA matrix in order
to obtain products with enhanced strength and toughness
has been researched in recent years [4, 6].
Glass compositions would be a good option for doping
apatite matrix. Goller et al. had used HA-bioglass (45S5)
composites. The HA used was human teeth derived
HA [7]. Batra et al. had used phosphate glass (CaO
P2O5Na2OCaF2 based glasses) and density, compressive
strength and hardness increased with increasing bioglass
content [8]. Salman et al. had used commercial
inert glass (CIG) to make HA composites. The HA
used was bovine hydroxyapatite [9]. They have shown
that glass additions can work as reinforcing phase for
HA bioceramic. To produce CIG no special sources are
needed. Simple use of some broken window glass is far
enough. But we must be very careful not to use crystal
ash trays, because those glasses contain lead. Addition
of lead makes easier the production of household crystals.
Those are produced with simply machining and we
must not forget that those are twice heavier than normal
glasses (i.e. CIG). But broken borglasses could be
also easily used. According to a recent study, Valério
et al. had used B2O3 glasses for cell culture. At the cell
culture study impressive results for cell culturing were
obtained [10]. Some US patents also result in boron containing
bioglass composites. Using boron will decrease
the melting temperature of bioglass compositions from
1450 C to 900 C [11, 12]. This dramatic decrease in
the temperature makes the production of such components
very economic. It is generally considered that the
presence of boron in glass composition assists and even
improves retentions of calcium, magnesium, and phosphorus
[13]. According to Behnamghader et al. HA composite
with 50 mol.% CaO and 50 mol.% P2O5 containing
glass decomposes to -tricalcium phosphate (TCP)
at 1300 C sintering temperature [14].
The aim of this study is to produce bioceramics composites
from CIG and synthetic HA to improve mechanical
strength of HA.
2. Materials and methods
The commercial synthetic hydroxyapatite (CSHA)
used in this study was obtained from Across company
(427)
428 N. Demirkol et al.
with average particle size of 6.5 m and molecular weight
of 502.31 g/mol. Table I shows the chemical analyses of
CIG with average particle size of 68 m. CSHA powder
was mixed with (separately) 5 and 10 wt% CIG powder
for 4 h. The samples were prepared according to a
British Standard for compression tests (BS 7253) [15].
The powder portions were pressed at 350 MPa between
hardened steel dies. Pressed samples were sintered between
1000 C and 1300 C (with the heating rate of
+5C min