國立高雄大學圖資館 |

Language: English

Back

Nanofiber reinforcement of a geopoly...

Colorado State University.

Nanofiber reinforcement of a geopolymer matrix for improved composite materials mechanical performance.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Nanofiber reinforcement of a geopolymer matrix for improved composite materials mechanical performance.
Author:	Rahman, AKM Samsur.
Description:	282 p.
Notes:	Source: Dissertation Abstracts International, Volume: 77-01(E), Section: B.
Notes:	Adviser: Donald W. Radford.
Contained By:	Dissertation Abstracts International77-01B(E).
Subject:	Mechanical engineering.
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3720781
ISBN:	9781339018867

Nanofiber reinforcement of a geopolymer matrix for improved composite materials mechanical performance.
Rahman, AKM Samsur.

Nanofiber reinforcement of a geopolymer matrix for improved composite materials mechanical performance. - 282 p.

Source: Dissertation Abstracts International, Volume: 77-01(E), Section: B.

Thesis (Ph.D.)--Colorado State University, 2015.

Geopolymers have the potential to cross the process performance gap between polymer matrix and ceramic matrix composites (CMC), enabling high temperature capable composites that are manufactured at relatively low temperatures. Unfortunately, the inherently low toughness of these geopolymers limits the performance of the resulting fiber reinforced geopolymer matrix composites. Toughness improvements in composites can be addressed through the adjustments in the fiber/matrix interfacial strength and through the improvements in the inherent toughness of the constituent materials. This study investigates the potential to improve the inherent toughness of the geopolymer matrix material through the addition of nanofillers, by considering physical dimensions, mechanical properties, reinforcing capability and interfacial bond strength effects.

ISBN: 9781339018867Subjects--Topical Terms:

190348
Mechanical engineering.

Nanofiber reinforcement of a geopolymer matrix for improved composite materials mechanical performance.
LDR:04797nmm a2200313 4500 001 476119
005 20160418090157.5
008 160517s2015 ||||||||||||||||| ||eng d
020 $a 9781339018867
035 $a (MiAaPQ)AAI3720781
035 $a AAI3720781
040 $a MiAaPQ $c MiAaPQ
100 1 $a Rahman, AKM Samsur. $3 730407
245 1 0 $a Nanofiber reinforcement of a geopolymer matrix for improved composite materials mechanical performance.
300 $a 282 p.
500 $a Source: Dissertation Abstracts International, Volume: 77-01(E), Section: B.
500 $a Adviser: Donald W. Radford.
502 $a Thesis (Ph.D.)--Colorado State University, 2015.
520 $a Geopolymers have the potential to cross the process performance gap between polymer matrix and ceramic matrix composites (CMC), enabling high temperature capable composites that are manufactured at relatively low temperatures. Unfortunately, the inherently low toughness of these geopolymers limits the performance of the resulting fiber reinforced geopolymer matrix composites. Toughness improvements in composites can be addressed through the adjustments in the fiber/matrix interfacial strength and through the improvements in the inherent toughness of the constituent materials. This study investigates the potential to improve the inherent toughness of the geopolymer matrix material through the addition of nanofillers, by considering physical dimensions, mechanical properties, reinforcing capability and interfacial bond strength effects.
520 $a A process optimization study was first undertaken to develop the ability to produce consistent, neat geopolymer samples, a critical precursor to producing nano-filled geopolymer for toughness evaluation. After that, single edge notched bend beam fracture toughness and un-notched beam flexural strength were evaluated for silicon carbide, alumina and carbon nanofillers reinforced geopolymer samples treated at various temperatures in reactive and inert environments. Toughness results of silicon carbide and carbon nanofillers reinforced geopolymers suggested that with the improved baseline properties, high aspect ratio nanofillers with high interfacial bond strength are the most capable in further improving the toughness of geopolymers. Among the high aspect ratio nanofillers i.e. nanofibers, 2vol% silicon carbide whicker (SCW) showed the highest improvement in fracture toughness and flexural strength of ~164% & ~185%, respectively. After heat treatment at 650 °C, SCW reinforcement was found to be effective, with little reduction in the performance, while the performance of alumina nanofiber (ANF) reinforced geopolymer significantly reduced. By means of SEM, EDS and X-ray diffraction techniques, it was found that the longer and stronger SCW is more capable of reinforcing the microstructurally inhomogeneous geopolymer than the smaller diameter, shorter ANF. After heat treatment at 760 °C, the effectiveness of SCW as reinforcement in both fracture toughness and flexural strength was reduced by ~89% and ~43%, respectively, while, the ANF filled materials performed worse than the neat geopolymer. A strong interaction was suggested between ANF and geopolymer at high temperature by means of chemical reactions and diffusion. SEM & X-ray diffraction results suggested the formation of Al4C3 on the SCW surface, which could reduce the interface strength between SCW and geopolymer. Therefore it is suggested that the interface strength should be as high as required for load transfer and crack bridging.
520 $a Finally, to investigate the potential synergy of a nano-filled matrix material and the fiber/matrix interface toughening mechanism of a continuous fiber composite, composite specimens were produced and tested. Flexural and shear strengths of Nextel 610 continuous fiber reinforced 2vol% SCW filled geopolymer matrix composites were investigated. Specimens were produced with cleaned Nextel fiber and with carbon-coated fibers to investigate the combinations of nano-filled matrix with continuous reinforcement that is well bonded (cleaned fiber) versus poorly bonded (carbon-coated fiber) to the matrix. The results showed that flexural strength of cleaned and coated fiber composites improved by ~35% and ~21% respectively, while shear strength of the similar composite systems improved by ~39.5% and ~24%. The results verified the effectiveness of SCW in toughening not only the neat geopolymer, but also continuous fiber reinforced geopolymer matrix composites.
590 $a School code: 0053.
650 4 $a Mechanical engineering. $3 190348
650 4 $a Materials science. $3 221779
650 4 $a Nanotechnology. $3 193873
690 $a 0548
690 $a 0794
690 $a 0652
710 2 $a Colorado State University. $b Mechanical Engineering. $3 730408
773 0 $t Dissertation Abstracts International $g 77-01B(E).
790 $a 0053
791 $a Ph.D.
792 $a 2015
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3720781