The durability of adhesive joints
Author(s)
Bland, David Jonathan
Type
Thesis
Abstract
One of the most important requirements of an adhesive joint is the ability to retain a
significant proportion of its load-bearing capability for the long periods under the wide
variety of environmental conditions encountered during its service-life. There exists a need
to improve the understanding of the mechanics and mechanisms associated with the
durability of adhesive joints in hostile environments, such as one of the most potentially
damaging and frequently encountered, water, to further their future extensive use in
engineering applications. In the present research, four important aspects in relation to the
durability of adhesive joints have been investigated. These were: (a) developing sound
short-term accelerated test methodologies to assess the durability of adhesive joints; (b)
understanding the mechanisms of environmental attack on different types of surface
pretreated adhesively bonded aluminium alloy substrates; (c) developing
adhesive/primer/pretreatment systems which possess excellent long-term durability; and (d)
investigating the potential of environmentally-friendly organosilanes as primers to enhance
the intrinsic adhesion of adhesive joints.
The results from these studies showed that: (a) constant displacement rate and cyclicfatigue
tests provide excellent quantitative durability test methodologies; (b) fracture
mechanics and advanced surface analysis of adhesive joints have proven surface
pretreatments using phosphoric acid anodising (PAA) are far superior to those employing a
grit blasting and degreasing (GBD) pretreatment which can be attributed to the increased
surface area and excellent bonding morphology of the anodised oxide surface, allowing
deep penetration of the viscous adhesive and impeding water ingress at the
adhesive/substrate interface; (c) the durability performance of PAA pretreated adhesive
joints employing a primer (PAAP) are superior to those without a primer specifically in
water, and acid-based surface pretreatments are significantly advanced compared to simple
GBD; and (d) the self assembling long carbon-chain silanes enhance the durability of
adhesive joints via the formation of covalent bonds between the adhesive and the activated
silane monolayer deposited on the substrate.
significant proportion of its load-bearing capability for the long periods under the wide
variety of environmental conditions encountered during its service-life. There exists a need
to improve the understanding of the mechanics and mechanisms associated with the
durability of adhesive joints in hostile environments, such as one of the most potentially
damaging and frequently encountered, water, to further their future extensive use in
engineering applications. In the present research, four important aspects in relation to the
durability of adhesive joints have been investigated. These were: (a) developing sound
short-term accelerated test methodologies to assess the durability of adhesive joints; (b)
understanding the mechanisms of environmental attack on different types of surface
pretreated adhesively bonded aluminium alloy substrates; (c) developing
adhesive/primer/pretreatment systems which possess excellent long-term durability; and (d)
investigating the potential of environmentally-friendly organosilanes as primers to enhance
the intrinsic adhesion of adhesive joints.
The results from these studies showed that: (a) constant displacement rate and cyclicfatigue
tests provide excellent quantitative durability test methodologies; (b) fracture
mechanics and advanced surface analysis of adhesive joints have proven surface
pretreatments using phosphoric acid anodising (PAA) are far superior to those employing a
grit blasting and degreasing (GBD) pretreatment which can be attributed to the increased
surface area and excellent bonding morphology of the anodised oxide surface, allowing
deep penetration of the viscous adhesive and impeding water ingress at the
adhesive/substrate interface; (c) the durability performance of PAA pretreated adhesive
joints employing a primer (PAAP) are superior to those without a primer specifically in
water, and acid-based surface pretreatments are significantly advanced compared to simple
GBD; and (d) the self assembling long carbon-chain silanes enhance the durability of
adhesive joints via the formation of covalent bonds between the adhesive and the activated
silane monolayer deposited on the substrate.
Date Issued
2009-02
Date Awarded
2009-07
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Kinloch, AJ
Taylor, Ambrose
Sponsor
EPSRC
Creator
Bland, David Jonathan
Publisher Department
Mechanical Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)