SAMPE Journal -September/October 2011 - 9
Figure 5. Changes in glass transition temperature as outtime increases. from the results presented in Figure 6b that the glass transition of the uncured epoxy could be used to accurately predict prepreg age for the 5320 system. Fit lines for enthalpy of reaction (R2=.79) and glass transition temperature (R2=.71) show a much higher degree of scatter, making them poor candidates for age prediction.
Tack Another property closely related to prepreg age is tack. To determine tack an energy of separation technique was used. Results are displayed below. It is clear from the data presented in Figure 7 that a large degree of error was present in the calculation of energy of separation. This is likely due to the sensitivity and degree of control available with the load frame used for testing. No clear trend in tack level as a function of out-time can be determined, but the data does show that after 22 days in ambient conditions the prepreg consistently displays a tack level of zero. Because the energy of separation technique described in the test method used showed a large degree of scatter, a second method was developed to calculate a representative measure of tack. The test method described by Ahn and colleagues19 uses only the area compressive region of the stress-strain plot to specify output energy. Actual tests were run, however, until the prepreg plies fully separated, which occurred significantly beyond the zero-point in fresh samples. This extension of the stress-strain curve for an unaged sample is shown in Figure 8 with photographs showing the adhesion and separation of adjacent prepreg plies. Calculating the area beyond the zero-strain point produced a plot of tack level vs. out-time showing an asymptotic decay in prepreg adhesion. The tack level can be seen to
Figure 6. Changes in DSC data as a function of out-time. (A) Enthalpy of reaction, (B) glass transition of the uncured system, (C) glass transition of the cured composite.
Figure 7. Energy of separation per unit volume as a function of aging time.
SAMPE Journal, Volume 47, No. 5, September/October 2011
Figure 8. Continuation of the tack stress-strain curve showing detachment of adjacent prepreg plies. Images show (1) compacted plies, (2) adhesion of plies in tension, (3) ply separation.
9
SAMPE Journal -September/October 2011
Table of Contents for the Digital Edition of SAMPE Journal -September/October 2011
SAMPE Journal - September/October 2011
Table of Contents
President’s Message
Technical Director’s Corner
Out-Time Effects on VBO (Vacuum Bag Only) Prepreg and Laminate Properties
Corporate Partners
SAMPE Tech 2011 Conference
SAMPE Tech 2011 Exhibition
Europe News & Views
SAMPE Europe’s SETEC 2011, Leiden
SAMPE Europe’s SEICO 2012, Paris
SAMPE China 2011
12th Japan International SAMPE Symposium and Exhibition – JISSE-12
SAMPE Books & CD’s Order Form
SAMPE Proceedings
Welcome SAMPE’s Newest Members
The SAMPE Foundation
Adhesive Characterization Using NIAR-Modified KGR Extensometer
Industry News
SAMPE LinkedIn Communities
SAMPE 2012 Call for Papers
SAMPE 2012 Exhibition
Materials & Products
SAMPE Asia 2012|Kuala Lumpur, Malaysia
SAMPE Materials Forecast Forum: Final Report
SAMPE Tech 2012 Call for Papers
SAMPE Journal Editorial Calender
Advertiser’s Index
Resource Center
Membership Application
Industry Events Calendar
Chapter Meetings Dates and Contacts
SAMPE Journal -September/October 2011 - SAMPE Journal - September/October 2011
SAMPE Journal -September/October 2011 - Cover2
SAMPE Journal -September/October 2011 - Table of Contents
SAMPE Journal -September/October 2011 - President’s Message
SAMPE Journal -September/October 2011 - 3
SAMPE Journal -September/October 2011 - 4
SAMPE Journal -September/October 2011 - Technical Director’s Corner
SAMPE Journal -September/October 2011 - Out-Time Effects on VBO (Vacuum Bag Only) Prepreg and Laminate Properties
SAMPE Journal -September/October 2011 - 7
SAMPE Journal -September/October 2011 - 8
SAMPE Journal -September/October 2011 - 9
SAMPE Journal -September/October 2011 - 10
SAMPE Journal -September/October 2011 - 11
SAMPE Journal -September/October 2011 - 12
SAMPE Journal -September/October 2011 - 13
SAMPE Journal -September/October 2011 - 14
SAMPE Journal -September/October 2011 - Corporate Partners
SAMPE Journal -September/October 2011 - SAMPE Tech 2011 Conference
SAMPE Journal -September/October 2011 - SAMPE Tech 2011 Exhibition
SAMPE Journal -September/October 2011 - Europe News & Views
SAMPE Journal -September/October 2011 - 19
SAMPE Journal -September/October 2011 - SAMPE Europe’s SETEC 2011, Leiden
SAMPE Journal -September/October 2011 - 21
SAMPE Journal -September/October 2011 - SAMPE Europe’s SEICO 2012, Paris
SAMPE Journal -September/October 2011 - 23
SAMPE Journal -September/October 2011 - SAMPE China 2011
SAMPE Journal -September/October 2011 - 25
SAMPE Journal -September/October 2011 - 12th Japan International SAMPE Symposium and Exhibition – JISSE-12
SAMPE Journal -September/October 2011 - SAMPE Books & CD’s Order Form
SAMPE Journal -September/October 2011 - SAMPE Proceedings
SAMPE Journal -September/October 2011 - 29
SAMPE Journal -September/October 2011 - Welcome SAMPE’s Newest Members
SAMPE Journal -September/October 2011 - 31
SAMPE Journal -September/October 2011 - 32
SAMPE Journal -September/October 2011 - 33
SAMPE Journal -September/October 2011 - The SAMPE Foundation
SAMPE Journal -September/October 2011 - 35
SAMPE Journal -September/October 2011 - 36
SAMPE Journal -September/October 2011 - Adhesive Characterization Using NIAR-Modified KGR Extensometer
SAMPE Journal -September/October 2011 - 38
SAMPE Journal -September/October 2011 - 39
SAMPE Journal -September/October 2011 - 40
SAMPE Journal -September/October 2011 - 41
SAMPE Journal -September/October 2011 - 42
SAMPE Journal -September/October 2011 - 43
SAMPE Journal -September/October 2011 - 44
SAMPE Journal -September/October 2011 - 45
SAMPE Journal -September/October 2011 - Industry News
SAMPE Journal -September/October 2011 - 47
SAMPE Journal -September/October 2011 - 48
SAMPE Journal -September/October 2011 - SAMPE LinkedIn Communities
SAMPE Journal -September/October 2011 - SAMPE 2012 Call for Papers
SAMPE Journal -September/October 2011 - SAMPE 2012 Exhibition
SAMPE Journal -September/October 2011 - Materials & Products
SAMPE Journal -September/October 2011 - 53
SAMPE Journal -September/October 2011 - SAMPE Asia 2012|Kuala Lumpur, Malaysia
SAMPE Journal -September/October 2011 - 55
SAMPE Journal -September/October 2011 - SAMPE Materials Forecast Forum: Final Report
SAMPE Journal -September/October 2011 - 57
SAMPE Journal -September/October 2011 - 58
SAMPE Journal -September/October 2011 - 59
SAMPE Journal -September/October 2011 - 60
SAMPE Journal -September/October 2011 - 61
SAMPE Journal -September/October 2011 - 62
SAMPE Journal -September/October 2011 - SAMPE Tech 2012 Call for Papers
SAMPE Journal -September/October 2011 - SAMPE Journal Editorial Calender
SAMPE Journal -September/October 2011 - 65
SAMPE Journal -September/October 2011 - Advertiser’s Index
SAMPE Journal -September/October 2011 - 67
SAMPE Journal -September/October 2011 - Resource Center
SAMPE Journal -September/October 2011 - 69
SAMPE Journal -September/October 2011 - 70
SAMPE Journal -September/October 2011 - 71
SAMPE Journal -September/October 2011 - 72
SAMPE Journal -September/October 2011 - 73
SAMPE Journal -September/October 2011 - 74
SAMPE Journal -September/October 2011 - Membership Application
SAMPE Journal -September/October 2011 - Chapter Meetings Dates and Contacts
SAMPE Journal -September/October 2011 - Cover3
SAMPE Journal -September/October 2011 - Cover4
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