國立虎尾科技大學 |

Mechanical and Fracture Properties of Soft Materials.

紀錄類型:	書目-語言資料,手稿 : Monograph/item
正題名/作者:	Mechanical and Fracture Properties of Soft Materials./
作者:	Otim, Kathryn J.
面頁冊數:	1 online resource (170 pages)
附註:	Source: Dissertation Abstracts International, Volume: 72-08, Section: B, page: 4916.
Contained By:	Dissertation Abstracts International72-08B.
標題:	Materials science. -
電子資源:	click for full text (PQDT)
ISBN:	9781124661582

Mechanical and Fracture Properties of Soft Materials.
Otim, Kathryn J.

Mechanical and Fracture Properties of Soft Materials. - 1 online resource (170 pages)

Source: Dissertation Abstracts International, Volume: 72-08, Section: B, page: 4916.

Thesis (Ph.D.)

Includes bibliographical references

The mechanical and fracture behavior of polymer gels is an area of increasing interest as these materials are currently being used in a wide range of applications. Despite their increased use, the implementation of polymer gels in practical applications is often limited by their low toughness. These materials exhibit unique failure behavior that cannot be modeled using traditional linear elastic fracture mechanics. This research aims to develop model systems that will allow us to examine the energy dissipation mechanisms that govern sample response across a broad range of deformations and contribute to an increase in toughness.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2018

Mode of access: World Wide Web

ISBN: 9781124661582Subjects--Topical Terms:

557839
Materials science.
Index Terms--Genre/Form:

554714
Electronic books.

Mechanical and Fracture Properties of Soft Materials.
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100 1 $a Otim, Kathryn J. $3 1182063
245 1 0 $a Mechanical and Fracture Properties of Soft Materials.
264 0 $c 2011
300 $a 1 online resource (170 pages)
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500 $a Source: Dissertation Abstracts International, Volume: 72-08, Section: B, page: 4916.
500 $a Adviser: Kenneth R. Shull.
502 $a Thesis (Ph.D.) $c Northwestern University $d 2011.
504 $a Includes bibliographical references
520 $a The mechanical and fracture behavior of polymer gels is an area of increasing interest as these materials are currently being used in a wide range of applications. Despite their increased use, the implementation of polymer gels in practical applications is often limited by their low toughness. These materials exhibit unique failure behavior that cannot be modeled using traditional linear elastic fracture mechanics. This research aims to develop model systems that will allow us to examine the energy dissipation mechanisms that govern sample response across a broad range of deformations and contribute to an increase in toughness.
520 $a Axisymmetric indentation experiments were conducted on cross-linked PDMS networks filled with an uncross-linked PDMS sol fraction. Despite a reduction in the elastic modulus, sample resistance to fracture was increased with the addition of sol fraction. Networks with high and medium cross-link densities exhibited three different modes of crack initiation, resulting from surface flaws or high tensile stresses at the corners of the probe, that were dependent upon the displacement at fracture. The rate-dependent fracture of loosely cross-linked PDMS gels was characterized using tensile tear tests. The energy release rate, G , was dependent upon both sample composition and crack velocity. The highest toughnesses were obtained from gels with large amounts of high molecular weight sol. Crack morphology also showed a velocity dependence and may be related to the length scale defined by G /E.
520 $a Double network gels served as the model for hybrid silica-triblock gels. These gels aim to optimize the load sharing mechanisms and fracture resistance of double network gels. The elastic modulus and recoverability of the samples was tested using indentation. An increase in triblock concentration resulted in an increase in the amount of deformation the samples could withstand before failure occurred. The mechanical response of samples with higher triblock concentrations was affected by aging temperature. Samples aged at room temperature had lower moduli and dissipated more energy than their high temperature counterparts. Preliminary X-ray scattering data confirm formation of the micellar triblock network in the samples.
520 $a Understanding the swelling behavior of hydrophilic polymers, such as polyethylene oxide and hydroxypropylmethylcellulose, is critical to optimizing the efficiency and accuracy of the drug-release profile from polymer matrices. Gel strength of polymer matrices, a key property related to hydration and swelling behavior, is commonly measured using texture analysis. This study found that indentation experiments provide an ideal alternative to conventional texture analysis for measuring gel strength. Because indentation experiments use a smaller punch and load cell, they are more sensitive to changes over a small range of displacements. Since the indentation experiments are nondestructive, measurements can be made on the same compact over time, allowing for better understanding of swelling behavior of a single tablet over several hours. This technique is also sensitive to changes in tablet thickness and mechanical response and can be used to characterize changes in the mechanical properties of the gel matrix during the swelling process.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2018
538 $a Mode of access: World Wide Web
650 4 $a Materials science. $3 557839
655 7 $a Electronic books. $2 local $3 554714
690 $a 0794
710 2 $a ProQuest Information and Learning Co. $3 1178819
710 2 $a Northwestern University. $b Materials Science and Engineering. $3 1181794
773 0 $t Dissertation Abstracts International $g 72-08B.
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3456590 $z click for full text (PQDT)