Poly(α-Hydroxy Ester)/Short Fiber Hydroxyapatite Composite Foams for Orthopedic Application

1995 ◽  
Vol 394 ◽  
Author(s):  
Robert C. Thomson ◽  
Michael J. Yaszemski ◽  
John M. Powers ◽  
Timothy P. Harrigan ◽  
Antonios G. Mikos
Keyword(s):  
Composite Material ◽  
Bone Regeneration ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Short Fiber ◽  
Processing Technique ◽  
Compressive Yield Strength ◽  
Short Fibers ◽  
Gelatin Microspheres ◽  
Composite Foams

AbstractA process has been developed to manufacture biodegradable composite foams of poly(DL-lactic- co-glycolic acid) (PLGA) and hydroxyapatite short fibers for use in bone regeneration. The processing technique allows the manufacture of three-dimensional foam scaffolds and involves the formation of a composite material consisting of a porogen material (either gelatin microspheres or salt particles) and hydroxyapatite short fibers embedded in a PLGA matrix. After the porogen is leached out, an open-cell composite foam remains which has a pore size and morphology defined by the porogen. The foam porosity can be controlled by altering the volume fraction of porogen used to make the composite material. Foams made using NaCl particles as a porogen were manufactured with porosities as high as 0.84±0.01 (n=3). The short hydroxyapatite fibers served to reinforce the PLGA. The compressive yield strength of foams manufactured using gelatin microspheres as a porogen was found to increase with fiber content. Foams with compressive yield strengths up to 2.82±0.63 MPa (n=3) with porosities of 0.47±0.01 (n=3) were manufactured using 30% by weight hydroxyapatite fibers in the initial composite prior to leaching. These composite foams with improved mechanical properties may also be expected to have enhanced osteoconductivity and hence provide a novel material which may prove useful in the field of bone regeneration.

Effect of Fiber Volume Fraction on High Temperature Creep of Al2O3-SiO2(sf)/AZ91D Composite

2011 ◽  
Vol 474-476 ◽  
pp. 548-552
Author(s):  
Jun Tian
Keyword(s):  
Creep Resistance ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Matrix Alloy ◽  
Short Fiber ◽  
Tensile Creep ◽  
Short Fibers ◽  
Creep Tests ◽  
Fiber Volume ◽  
The Matrix

Constant stress tensile creep tests were conducted on AZ91D–20 vol.%, 25 vol.%, and 30 vol.% Al2O3-SiO2short fiber composites and on an unreinforced AZ91D matrix alloy. The creep resistance of the reinforced materials is shown to be considerably improved compared with the matrix alloy. With the increasing volume fraction of short fibers, the creep resistance of AZ91D composites is improved, and their creep threshold stresses are also increased accordingly. Because of the increasing volume fraction of short fibers, loads of bearing and transmission of short fibers will increase, and thus the creep resistance of AZ91D composites further improves, but the precipitation of β-Mg17Al12precipitate increases in the number, it is easy to soften coarse, so that threshold stress of AZ91D composite does not increase greatly.

Experimental Study on Manufacturing Process of Short Fiber-Rubber Composite Material Using New Type Six-Wing Synchronous Rotor

2009 ◽  
Vol 87-88 ◽  
pp. 317-322
Author(s):  
De Wei Zhang ◽  
Chuan Sheng Wang
Keyword(s):  
Experimental Study ◽  
Composite Material ◽  
Manufacturing Process ◽  
Short Fiber ◽  
Short Fibers ◽  
Rubber Composite ◽  
New Type ◽  
Mechanical Performances

A new type of six-wing synchronous rotor has been designed and manufactured for mixing requirements of the short fiber-rubber composite material. During the manufacturing process of the composite material, different addition proportions of the short fibers have been used. The physical and mechanical performances of the short fiber-rubber composite material have been investigated. The new type rotor meets the mixing requirements of the short fiber-rubber composite material, with the best addition proportion of the short fibers.

scholarly journals PENGARUHORIENTASI DANFRAKSI VOLUME SERAT DAUN NANAS (ANANAS COMOSUS)TERHADAP KEKUATAN TARIK KOMPOSIT POLYESTERTAK JENUH(UP)

2012 ◽  
Vol 2 (1) ◽  
Author(s):  
Paryanto Dwi Setyawan ◽  
Nasmi Herlina Sari ◽  
Dewa Gede Pertama Putra
Keyword(s):  
Tensile Strength ◽  
Fiber Orientation ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Short Fiber ◽  
Ananas Comosus ◽  
Short Fibers ◽  
Random Orientation ◽  
Fiber Volume ◽  
Pineapple Leaves

Composite manufacturing is done by hand lay-up method with a fiber volume fraction 10%, 20%, 30%, and 40% with unidirectional and random short fiber orientation of pineapple leaves. Specimen testing is performed with a standard tensile strength test ASTM D3039. As a results is known that the tensile strength of composites increased with increasing fiber volume fraction for unidirectional fiber orientation, but rather to the random orientation of short fibers. Meanwhile, the composite tensile strain increases withincreasingfibervolume fractionfor both theorientation of thefibersof pineappleleaves.

A Novel Biodegradable Poly(Lactic-Co-Glycolic Acid) Foam for Bone Regeneration

1993 ◽  
Vol 331 ◽  
Author(s):  
Robert C. Thomson ◽  
Michael J. Yaszemski ◽  
John M. Powers ◽  
Antonios G. Mikos
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Composite Material ◽  
Bone Regeneration ◽  
Pore Size ◽  
Glycolic Acid ◽  
Average Molecular Weight ◽  
Gelatin Microspheres ◽  
Degradable Polymer ◽  
Biodegradable Poly

AbstractWe present a novel method for manufacturing three-dimensional, biodegradable poly(DL-lactic-co-glycolic acid) (PLGA) foam scaffolds for use in bone regeneration. The technique involves the formation of a composite material consisting of gelatin microspheres surrounded by a PLGA matrix. The gelatin microspheres are leached out leaving an open-cell foam with a pore size and morphology defined by the gelatin microspheres. The foam porosity can be controlled by altering the volume fraction of gelatin used to make the composite material. PLGA 50:50 was used as a model degradable polymer to establish the effect of porosity, pore size, and degradation on foam mechanical properties. The compressive strengths and moduli of PLGA 50:50 foams were found to decrease with increasing porosity but were largely unaffected by pore size. Foams with compressive strengths up to 2.5 MPa were manufactured. From in vitro degradation studies we established that for PLGA 50:50 foams the mechanical properties declined in parallel with the decrease in molecular weight. Below a weight average molecular weight of 10,000 the foam had very little mechanical strength (0.02 MPa). These results indicate that PLGA 50:50 would not be suitable as a scaffold material for bone regeneration. However, the dependence of mechanical properties on porosity, pore size, and degree of degradation which we have determined will aid us in designing a PLGA foam (with a comonomer ratio other than 50:50) suitable for bone regeneration.

Experimental Study of Screw Speed Effects on Quality of Short Fiber-Rubber Composite Material

2011 ◽  
Vol 221 ◽  
pp. 369-372 ◽  
Author(s):  
Chuan Sheng Wang ◽  
De Wei Zhang ◽  
Hui Guang Bian ◽  
Xiao Bo Wang ◽  
Lei Guo
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Composite Material ◽  
Physical And Mechanical Properties ◽  
Short Fiber ◽  
Experimental Results ◽  
Short Fibers ◽  
Screw Speed ◽  
Rubber Composite

During the extruding process of short fiber-rubber composite material, screw speed is an important factor which influences the orientation of short fibers, as well as the physical and mechanical properties of short fiber-rubber composite material. The effects of different screw speeds on physical and mechanical properties of short fiber-rubber composite material have been studied by experimental study. In the experiments, the screw speeds were 10rpm, 15rpm, 20rpm, 25rpm and 30rpm respectively. The experimental results indicated that when the screw speed was 15rpm, the physical and mechanical properties of short fiber-rubber composite material are better.

Isotropic Properties of Platelet-Reinforced Media

1979 ◽  
Vol 101 (3) ◽  
pp. 299-303 ◽  
Author(s):  
R. M. Christensen
Keyword(s):  
Composite Material ◽  
Edge Effects ◽  
Volume Fraction ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Effective Moduli ◽  
Dilute Suspension ◽  
Stiffening Effect ◽  
Special Case ◽  
Three Dimensional Space

The effective moduli are derived for a composite material containing platelet-type inclusions. The platelets are taken to be randomly oriented in three-dimensional space and to have so large a diameter-to-thickness ratio that edge effects can be neglected. The effective moduli that are derived reduce to known results in the special case of a dilute suspension. Comparisons are made with the corresponding type of composite medium that involves randomly oriented fibers. For the same volume fraction of reinforcing phase, the platelet case provides a stiffening effect about three times greater than the fiber case.

Effective Longitudinal Young’s Modulus of Misoriented Short Fiber Composites

1982 ◽  
Vol 49 (3) ◽  
pp. 536-540 ◽  
Author(s):  
Y. Takao ◽  
T. W. Chou ◽  
M. Taya
Keyword(s):  
Young’S Modulus ◽  
Volume Fraction ◽  
Young's Modulus ◽  
Orientation Distribution ◽  
Short Fiber ◽  
Short Fibers ◽  
Fiber Volume ◽  
Equivalent Inclusion Method ◽  
Equivalent Inclusion ◽  
Fiber Orientation Distribution

This paper examines the effective longitudinal Young’s modulus of composites containing misoriented short fibers. The analysis is based on the Eshelby’s equivalent inclusion method and the average induced strain approach of Taya, Mura, and Chou. The present approach is unique in that it takes into account the interactions among fibers at different orientations. Numerical results are presented to demonstrate the effects of fiber elastic property, aspect ratio, volume fraction, and orientation distribution function on composite Young’s modulus. Fiber orientation distribution has a more significant effect on composite longitudinal Young’s modulus than fiber volume friction, within the range examined.

Effect of Die Structure on Radial Orientation of Short Fiber in Tire Tread and its Performance

2012 ◽  
Vol 501 ◽  
pp. 247-252 ◽  
Author(s):  
De Wei Zhang ◽  
Chuan Sheng Wang ◽  
Guang Yi Lin ◽  
Shao Ming Li ◽  
Chun Ping Chen
Keyword(s):  
Composite Material ◽  
Short Fiber ◽  
Channel Length ◽  
Channel Height ◽  
Manufacturing Processes ◽  
Short Fibers ◽  
Orientation Degree ◽  
Radial Orientation ◽  
Die Structure ◽  
Rubber Composite

Extrusion and molding is one of the most important manufacturing processes of short fiber-rubber composite material. In order to be used to tire tread, the short fibers in rubber are wanted to be radial orientated. But the orientation of short fibers depends on the die structure, and the performances of short fiber-rubber composite material depend on the radial orientation degree of short fibers. So, the die structure has been studied by experiments in order to get a proper die structure for manufacturing of short fiber-rubber composite material. The experimental results indicate that the proper die structure parameters are: the molding length is 15mm, the molding height is 9mm, the channel length is 75mm, the channel height is 12mm and the channel angle is 135º.

Research on Vulcanization Process of Short Fiber-Rubber Composite Material

2012 ◽  
Vol 501 ◽  
pp. 325-329
Author(s):  
Chuan Sheng Wang ◽  
De Wei Zhang ◽  
Lei Guo ◽  
Xian Kui Zeng ◽  
Xiao Bo Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Physical And Mechanical Properties ◽  
Short Fiber ◽  
Short Fibers ◽  
Iron Wire ◽  
Rubber Composite ◽  
Fibers Orientation ◽  
Vulcanization Process

Vulcanization process is the last step of manufacturing rubber products. For tire tread which is made of short fiber rubber composite material, vulcanization is complex due to during vulcanization process the flow of mixed rubber maybe change short fibers orientation. As a result, during vulcanization process, several pieces of iron wire have been put in the mold to play the role of tire patterns for the first step research. The experimental results indicate that the flow of mixed rubber would not change short fibers orientation greatly, and physical and mechanical properties of short fiber-rubber composite material keep as good as that vulcanized without iron wire.

Fatigue Property and Fatigue Crack Propagation Behavior of Al2O3/A6061 MMCs at Room and Elevated Temperature

2004 ◽  
Vol 261-263 ◽  
pp. 1073-1078 ◽  
Author(s):  
Yasuo Ochi ◽  
Kiyotaka Masaki ◽  
Takashi Matsumura ◽  
M. Wadasako
Keyword(s):  
Fatigue Strength ◽  
Crack Initiation ◽  
Fiber Volume Fraction ◽  
Elevated Temperatures ◽  
Volume Fraction ◽  
Fatigue Property ◽  
Short Fiber ◽  
Short Fibers ◽  
Fiber Volume ◽  
Large Size

The rotating bending fatigue tests in high cycle region were carried out on alumina short fiber reinforced aluminum alloy composites (MMCs) at room and elevated temperatures of 200, 350, 400 and 450°C. The four kind of MMCs with 0%, 10%, 18% and 25% volume fraction were prepared in order to investigate the effects of alumina short fiber volume fraction on the fatigue property such as the fatigue strength, the crack initiation and propagation behaviors. As results, it was found that the fatigue strength at 107 cycles decreased with increase in the test temperature, but increased with an increase in alumina short fiber volume fraction at room and elevated temperatures. The crack initiation sites were large size alumina short fibers; some kind of cluster of short fibers and large size alumina particles (i.e. shots). And the crack growth paths were related to the distribution of the short fibers.

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