This document describes a study investigating the tensile properties of nano-composite materials manufactured using the Vacuum Assisted Resin Transfer Molding (VARTM) process. It details the materials used including unidirectional carbon fiber sheets, epoxy matrix, and halloysite nanoclay filler. Methods for fabricating composite laminates with and without nano-fillers using VARTM are presented. Mechanical properties were experimentally determined through tensile testing according to ASTM standards and analytically calculated. Results were compared to evaluate the effect of nano-filler inclusion and manufacturing technique.

1. MESF6950C Independent Project
Tensile properties of Nano-composite materials
manufactured with VARTM process
KARTCEV Egor
20304323
May 2016

2. 2
List of contents
Abstract ......................................................................................................................7
Introduction................................................................................................................8
1. Material Used..............................................................................................10
1.1. Unidirectional carbon fiber sheets ..............................................................10
1.2. Epoxy matrix...............................................................................................11
1.3. Nano-material..............................................................................................11
2. Composite material without Nano-fillers manufactured using the Vacuum-
Assisted Resin Infusion Process (VARIP) .................................................13
2.1. Fabrication...................................................................................................13
2.1.1. Preparation of mould, layers and lay-up.....................................................13
2.1.2. Bagging .......................................................................................................14
2.1.3. Preparation of resin .....................................................................................16
2.1.4. Infusion .......................................................................................................16
2.1.5. Curing..........................................................................................................17
2.2. Inspection of laminates ...............................................................................18
2.3. Specimen preparation..................................................................................25
2.4. Experimental determination of mechanical properties ...............................28
2.5. Analytic determination of certain mechanical properties...........................39
2.6. Comparison of analytic and experimental results.......................................40
3. Composite material with Nano-fillers manufactured using Vacuum-
Assisted Resin Transfer Mould (VARTM) ................................................41
3.1. Fabrication...................................................................................................41
3.1.1. Preparation of the solution with Nano-material..........................................41
3.1.2. Adjustment of the mould.............................................................................42
3.1.3. Preparation and placement of carbon fibers and mat..................................45
3.1.4. Mixing of resin............................................................................................46
3.1.5. Degassing ....................................................................................................47
3.1.6. Infusion .......................................................................................................47
3.1.7. Cleaning ......................................................................................................51
3.1.8. Curing..........................................................................................................51
3.2. Inspection of laminates ...............................................................................52
3.3. Specimen’s preparation...............................................................................55
3.4. Experimental determination of mechanical properties ...............................57

3. 3
4. Composite material without Nano-fillers manufactured using Vacuum-
Assisted Resin Transfer Mould (VARTM) ................................................62
4.1. Fabrication...................................................................................................62
4.2. Inspection of laminates ...............................................................................63
4.3. Specimen preparation..................................................................................65
4.4. Experimental determination of mechanical properties ...............................67
4.5. Analytic determination of some mechanical properties .............................73
4.6. Comparison of analytic and experimental results.......................................74
5. Conclusion...................................................................................................75
6. References...................................................................................................79

4. 4
List of tables
Table 1. Specifications of the specimens according to ASTM standards. ................9
Table 2. Properties of unidirectional carbon fiber sheets (Toray T 200) ................10
Table 3. Properties of resin for unidirectional carbon fiber sheets..........................11
Table 4. Properties of Nano-material.......................................................................12
Table 5. C-scan characteristics ................................................................................20
Table 6. The results of ultra-sonication of VARIP laminates .................................22
Table 7. Specimen dimensions ................................................................................26
Table 8. The results of 0° longitudinal tensile tests.................................................32
Table 9. The results of 90° longitudinal tensile tests...............................................34
Table 10. The results of [45/0/-45/90]s longitudinal tensile tests............................36
Table 11. The results of [45/-45] longitudinal tensile tests. ....................................37
Table 12. VARIP experimental mechanical properties of composites....................38
Table 13. Analytical mechanical properties ............................................................40
Table 14. Comparison of mechanical properties .....................................................40
Table 15. The results of inspection of VARTM laminates with Nano-fillers.........52
Table 16. Specimen dimensions ..............................................................................56
Table 17. The results of 0° longitudinal tensile tests...............................................59
Table 18. The results of 90° longitudinal tensile tests.............................................60
Table 19. The results of [45/-45] longitudinal tensile tests .....................................62
Table 20. Experimental mechanical properties........................................................62
Table 21. The results of inspection of VARTM laminates without Nano-fillers....63
Table 22. Specimen dimensions ..............................................................................66
Table 23. The results of 0° longitudinal tensile tests...............................................68
Table 24. The results of 90° longitudinal tensile tests.............................................70
Table 25. The results of [45/-45] longitudinal tensile tests .....................................72
Table 26. Experimental mechanical properties........................................................73
Table 27. Analytical mechanical properties ............................................................74
Table 28. Comparison of mechanical properties .....................................................74
Table 29. Summary of the mechanical properties ...................................................75

5. 5
List of figures
Figure 1. A Unidirectional Carbon Fiber Sheet.......................................................10
Figure 2. Nanomaterial (with microscopic view on right) ......................................12
Figure 3. The preparation of the mould and lay-up of carbon fibers.......................13
Figure 4. Schematic diagram of the resin infusion tube ..........................................14
Figure 5. The protection layer..................................................................................15
Figure 6. The mould prepared for the infusion........................................................15
Figure 7. The infusion process.................................................................................17
Figure 8. C-scan .......................................................................................................18
Figure 9. Ultra-sonication ........................................................................................19
Figure 10. Visible surface defects of failed laminates.............................................19
Figure 11. Marking of the laminates........................................................................25
Figure 12. The preparation of the specimens...........................................................25
Figure 13. Set up of the tensile machine..................................................................28
Figure 14. Typical fracture pattern of a sample.......................................................29
Figure 15. 2015-10-24-[0]-6-1 stress-strain response .............................................29
Figure 16. 2015-10-24-[0]-6-2 stress-strain response .............................................30
Figure 17. 2015-10-24-[0]-6-3.................................................................................30
Figure 18. 2015-10-24-[0]-6-4 stress-strain response .............................................31
Figure 19. 2015-10-24-[0]-6-5.................................................................................31
Figure 20. 2015-11-05-[90]-10-3 stress-strain response .........................................32
Figure 21. 2015-11-05-[90]-10-4 stress-strain response .........................................33
Figure 22. 2015-11-05-[90]-10-5 stress-strain response .........................................33
Figure 23. 2015-11-12-[45/0/-45/90]s -8-1 .............................................................34
Figure 24. 2015-11-12-[45/0/-45/90]s -8-3 stress-strain response...........................35
Figure 25. 2015-11-12-[45/0/-45/90]s -8-5 stress-strain response...........................35
Figure 26. 2015-11-19-[45/-45]-6-1 ........................................................................36
Figure 27. 2015-11-19-[45-45]-6-5 stress-strain response......................................37
Figure 28. Preparation of the solution of Nano-material and hardener...................41
Figure 29. Preparation of the solution of Nano-material and hardener...................42
Figure 30. Adjustment of the mould........................................................................43
Figure 31. Connection of the tubes..........................................................................43
Figure 32. Sealing of the mould’s gaps ...................................................................44
Figure 33. Carbon fibers lay-up and mat .................................................................45
Figure 34. Covering of the mould............................................................................46

6. 6
Figure 35. Preparation of the resin...........................................................................46
Figure 36. Degassing................................................................................................47
Figure 37. The pot for extra resin ............................................................................47
Figure 38. Prepared set-up for infusion ...................................................................48
Figure 39. Infusion...................................................................................................49
Figure 40. Bubbles in the vacuum tube ...................................................................50
Figure 41. Sealing of the tubes ................................................................................50
Figure 42. Cleaning..................................................................................................51
Figure 43. Heating....................................................................................................51
Figure 43. Preparation of the specimens..................................................................55
Figure 44. 2016-01-27-[0]-6-1 stress-strain response .............................................57
Figure 45. 2016-01-27-[0]-6-2 stress-strain response .............................................58
Figure 46. 2016-01-27-[0]-6-3 stress-strain response .............................................58
Figure 47. 2016-02-04-[90]-12-2.............................................................................59
Figure 48., 2016-02-04-[90]-12-3 stress-strain response ........................................60
Figure 49. 2016-02-01-[45/-45]-6-1 stress-strain response.....................................61
Figure 50. 2016-02-01-[45/-45]-6-3 ........................................................................61
Figure 51. 2016-03-10-[0]-6-1 stress-strain response .............................................67
Figure 52. 2016-03-10-[0]-6-2 stress-strain response .............................................67
Figure 53. 2016-03-10-[0]-6-3 stress-strain response .............................................68
Figure 54. 2016-03-09-[90]-12-1.............................................................................69
Figure 55. 2016-03-09-[90]-12-2 stress-strain response .........................................69
Figure 56. 2016-03-09-[90]-12-3 stress-strain response .........................................70
Figure 57. 2016-03-15-[45/-45]-6-1 stress-strain response.....................................71
Figure 58. 2016-03-15-[45/-45]-6-2 stress-strain response.....................................71
Figure 59. 2016-03-15-[45/-45]-6-3 ........................................................................72
Figure 60. Image of the arrested crack tip [4]..........................................................76
Figure 61. Bridging of the fracture surfaces with Nano-tubes [4]...........................77
Figure 62. Toughening mechanism of quasi-static fracture ....................................77

7. 7
Abstract
This paper aims to determine how the introduction of nano-particles into carbon
fiber-reinforced composite material can change its mechanical properties.
Two different manufacturing techniques were considered: Vacuum bagging and
VARTM. A number of the specimens were prepared and then tested following
ASTM standards: ASTM D3039/D3039M-00 and D3518/D3518M-13 [5, 6].
Analytical determination of certain mechanical properties was also conducted.

8. 8
Introduction
Composite materials can provide the best weight-performance properties which
can be applied in many different fields of design and construction. These
properties can be achieved by combining matrix and reinforcement material with
different mechanical properties. There are two levels of reinforcement of carbon
fiber-reinforced composites. The first level, which is called traditional composites,
includes two ingredients: the epoxy matrix and carbon fibers, where fibers are
expected to carry the main load, whereas the matrix protect them from the
aggressive environment and support fibers in the certain position. The second level
of reinforcement includes composite, described above, which is reinforced with
nano-fillers. The reinforcing principle in nano-scale is different from that in marco-
scale. The carbon fibers, interacting with the matrix, form an interface between
them, the stronger the interface, the better mechanical properties of the composite.
Nano-particles form an interphase between them and the matrix, the properties of
the interphase differ from the original properties of both those materials, in the
case of debonding, the separation line will follow the outer boundary of the
interphase, increasing the fracture energy.
The main aim of this project is to determine, using tensile test, the mechanical
properties of carbon fiber reinforced composite materials with Nano-particles
manufactured using the VARTM process. The tests have been performed
according to the ASTM standards. To make a comprehensive assessment, the
results of laminates without Nano-fillers and laminates prepared with a different
manufacturing technique, called the Vacuum-Assisted Resin Infusion process,
were compared. Further, the analytic determination of certain mechanical
properties is also presented in this report.

9. 9
The specimens were prepared according to the specifications described in the
ASTM standards [5, 6].
Table 1. Specifications of the specimens according to ASTM standards.
Test
method
Type
Ply
count
Fiber
orientation, (°)
Gauge
length, mm
Size of
specimens, mm
ASTM
D 3039
Longitudinal 6 [0] 139.7 12.7 by 292.1
Transverse 12 [90] 152.4 19.1 by 228.6
ASTM
D 3518
Shear 6 [45/-45] 139.7 25.4 by 292.1

10. 10
1. Material Used
1.1. Unidirectional carbon fiber sheets
Table 2. Properties of unidirectional carbon fiber sheets (Toray T 200)
Properties Unit MRL-T700-200 Test method
Carbon fiber area weight g/cm2
200 ASTM D3776
Tensile strength kg/cm-ply 460 ASTM D3039
Tensile modulus kg/cm-ply 25800 ASTM D3039
Tensile strength for design MPa 4200 ASTM D3039
Tensile modulus for design GPa 235 ASTM D3039
Elongation % 1.8 ASTM D3039
Functional properties of fibers
CTE: -0.38 .10-6
/ C
Specific Heat: 0.18 Cal/g. C
Thermal Conductivity: 0.0224 Cal/cm.s. C
Electric Resistivity: 1.6 x 10-3
.cm
Chemical Composition: Carbon 93%, Na + K < 50 ppm
Figure 1. A Unidirectional Carbon Fiber Sheet

11. 11
1.2. Epoxy matrix
Epoxy: MRT-A1, made in Taiwan; Hardener: MRL-B1, made in Taiwan
Table 3. Properties of resin for unidirectional carbon fiber sheets.
Specification Test method
Material
Room Temperature
Cured Epoxy Resin
Work life at 25 C 60-100 min
CNS 13065
ASTM D2471
Viscosity at 25 C 900-2000cps
CNS 13065
ASTM D2471
Tensile strength
Completely cured for 7
days at 25 C
>30 MPa
CNS 4396
ASTM D638
Tensile modulus
Completely cured for 7
days at 25 C
>3.5 GPa
CNS 4396
ASTM D638
Flexural strength
Completely cured for 7
days at 25 C
>56 MPa
CNS 4392
ASTM D790
Shear strength
Completely cured for 7
days at 25 C
>10 MPa
CNS 5606
ASTM D1002
1.3. Nano-material
Specification:
Name: Halloysite Nanoclay,
Product number: 685445-500G,
Manufacturer: Sigma-albrich company of USA

12. 12
Table 4. Properties of Nano-material.
Diameter x L 30-70 nm x 1-3 m, Nanotube
Color 75-96, Hunter Brightness
Refractive Index n20/D 1.54
CAS number 1332-58-7
Formula H2Al2O9Si2 2 H2O
Molecular Weight 294.19
Pore size 1.26-1.34 mL/g pore volume
Surface area 64m2
/g
Capacity 8.0 meq/g cation exchange capacity
Figure 2. Nanomaterial (with microscopic view on right)