The effect of curing schedules on fiber-matrix adhesion in carbon fiber–epoxy resin composites

2021 ◽  
pp. 002199832110604
Author(s):  
Luke ElKhoury ◽  
John C Berg
Keyword(s):  
Yield Strength ◽  
Carbon Fibers ◽  
Curing Temperature ◽  
Scanning Calorimetry ◽  
Degree Of Cure ◽  
Matrix Adhesion ◽  
Plastic Yield ◽  
Fiber Matrix ◽  
Fiber Fragmentation ◽  
Carbon Fiber Epoxy

Fiber-reinforced polymeric composites are used in a large and growing number of applications, all requiring different property sets including the nature of the fiber-matrix adhesion to which the present work is addressed. Specifically, the number of curing cycles, curing temperature and schedule, degree of cure, use of accelerants, annealing, and the use of fiber handling agents are investigated for systems of Hexcel IM7 carbon fibers embedded in Epon862 (resin) and Epikure Curing Agent W (hardener) using the single-fiber fragmentation method. The fractional extent of cure is monitored using differential scanning calorimetry (DSC), so that comparisons are made at the same degree of cure (99%). Single-stage curing at the highest temperature produces the highest apparent adhesion, and the use of accelerants significantly increases the curing rate while maintaining the same level of adhesion. Accelerants in some cases, however, decrease the plastic yield strength of the specimens. Annealing reduces induced residual stress and apparent adhesion, but not below the baseline achieved at lower curing temperatures. Plastic yield strength and apparent adhesion decrease for any degree of cure lower than 95%, while the use of handling agents shows no effect on adhesion.

Cryogenic Microcracking of Carbon Fiber/Epoxy Composites: Influences of Fiber-Matrix Adhesion

2003 ◽  
Vol 37 (21) ◽  
pp. 1939-1950 ◽  
Author(s):  
John F. Timmerman ◽  
Brian S. Hayes ◽  
James C. Seferis
Keyword(s):  
Carbon Fiber ◽  
Epoxy Composites ◽  
Matrix Adhesion ◽  
Fiber Matrix ◽  
Carbon Fiber Epoxy

An Investigation of the Influence of Interface Chemical Structure on Fiber/Matrix Adhesion

2006 ◽  
Vol 977 ◽  
Author(s):  
Dharmaraj Raghavan
Keyword(s):  
Mass Fraction ◽  
Chemical Structure ◽  
Primary Objective ◽  
Self Assembled Monolayer ◽  
Matrix Adhesion ◽  
In Situ Modification ◽  
Fiber Matrix ◽  
Fiber Breaks ◽  
Fiber Fragmentation ◽  
The Impact

AbstractThe primary objective of the study is to investigate the impact of chemical structure at the interface on the interface strength of fiber/matrix composite. A solvent based method was used to deposit trichlorosilane on E-glass fiber surfaces followed by in situ modification of the deposited layer to prepare pure and mixed amine undecyl self assembled monolayer (SAM). The extent of fiber/matrix adhesion was determined by performing single fiber fragmentation test (SFFT). The SFFT data indicate that ≈ 85 % of fiber breaks obtained for epoxy composite occurs at a much lower mass fraction of amine coverage for SAM while a similar number of fiber breaks occur at a much higher mass fraction of amine coverage for aqueous solution deposited coupling agent system.

Application of CNT Enhanced Carbon Fibers in Hybrid Composites with Improved Interfacial Properties

2013 ◽  
Vol 832 ◽  
pp. 237-242 ◽  
Author(s):  
Shazed Md. Aziz ◽  
Suraya Abdul Rashid ◽  
Saeed Rahmanian ◽  
Mohamad Amran Mohd Salleh
Keyword(s):  
Mechanical Properties ◽  
Carbon Fibers ◽  
Hybrid Composites ◽  
Chemical Vapor ◽  
Interfacial Properties ◽  
Single Fiber ◽  
Growth Time ◽  
Atmospheric Conditions ◽  
Matrix Adhesion ◽  
Fiber Matrix

Growing carbon nanotubes (CNT) on the surface of high performance carbon fibers (CF) offers a means to tailor the mechanical properties of the fiber-matrix interface of a composite. In the context of this work, a floating catalyst chemical vapor deposition (CVD) unit was utilized to grow CNT onto the surface of CF. The surface and mechanical properties of the resultant fibers, CNT density and alignment morphology were explained to depend on the CNT growth temperature, growth time, and atmospheric conditions within the CVD chamber. Single fiber/Epoxy composite coupons were fabricated by using both neat and CNT-coated CF to conduct single fiber fragmentation test (SFFT). It was observed that the coating of CNT onto CF surface improves the IFSS between CF and matrix when compared with neat-CF. Particularly, CF treatment condition for CNT-coating with 700 °C reaction temperature and 30 minutes reaction time has shown a considerable increase in IFSS approximately of 45% over that of the untreated fiber from which it was processed. The fiber-matrix adhesion was analyzed by using SEM on cryogenically fractured surface of both types of composites. The proper justification of fiber-matrix adhesion featured by composite interfacial properties was explained through IFSS.

Improving Wire Sweep Performance by Measuring Degree of Cure of Epoxy Mold Compounds

2011 ◽  
Author(s):  
Sheila Liza B. Dal
Keyword(s):  
Differential Scanning Calorimetry ◽  
Shelf Life ◽  
Trial And Error ◽  
Active Components ◽  
Scanning Calorimetry ◽  
Degree Of Cure ◽  
Electronic Package ◽  
Viscosity Changes ◽  
Epoxy Mold Compounds

Abstract The choice of epoxy mold compound (EMC) for an electronic package is based mostly on how much protection it provides to the active components in the package. But the choice is not a straightforward process. Rather it is mostly trial and error using different assembly parameters to find the most robust material while assembly defects are monitored. One such defect associated to EMC processing is wire sweep, and many studies have shown that it is mainly caused by viscosity changes in the EMC. In this study, samples of EMC in various stages of shelf life and staging times were analyzed for degree of cure using a method called differential scanning calorimetry (DSC). Samples are then processed at assembly for wire sweep measurement. It was found out that degree of cure increases with staging time at different rates for each shelf life. It was also found out that wire sweep did not only increase with degree of cure but it was also found to be predictable with respect to the latter. Using this information, the age and staging limit for each material was identified that would not cause wire sweep issues.

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