1. Polymer Matrix Composites Matrix Resins and Composite Fabrication
Polymer Matrix Composites Matrix Resins and Composite Fabrication
NESC Academy Materials
Technology Discipline Team
Brian J. Jensen, Ph.D.
March, 2011
MODIFIED COMPLETELY

2. Objectives Provide Introduction to Polymeric Matrices for Composites.
Objectives
Provide Introduction to Polymeric Matrices for
Composites.
Provide Introduction to Processing of Polymeric
Matrix Composites.

3. Outline Introduction to Polymers Composite Fabrication Processes
Outline
Introduction to Polymers
Thermoplastics
Thermosets
Definitions
Composite Fabrication Processes
Fabrication Methods
Required Polymer Properties
Advantages/Disadvantages
MODIFIED COMPLETELY

4. Polymeric Material Types
Polymeric Material Types
Thermoplastics
High Molecular Weight (Large)
Nonreactive / Reprocessable
High Melt Viscosity
Thermosets
Low Molecular Weight (Small)
Reactive / Crosslinked / Not Reprocessable
Low Melt Viscosity

5. Polymer Properties Controlled by Molecular Structure
Polymer Properties Controlled by Molecular Structure
Processability
Physical (Tg, CTE)
Mechanical (strength, stiffness)
Toughness
Solvent Resistance
Environmental Resistance (thermal, radiation)
Durability

6. Environments Affecting Polymer Durability
• Temperature
• Stress
• Time
• Atmosphere
• Chemical, mechanical and electrical action
• Radiation
Durability - Capacity of a material to retain useful properties
for a required period of time under environmental conditions of application.

7. Role of Fiber & Matrix Role of Matrix Role of Fiber
Role of Fiber & Matrix
Role of Fiber
• Carries In-Plane Loads: Provides stiffness & Strength
• Reduces Thermal Coefficient Of Expansion
Role of Matrix
• Bonds and Holds Filaments In Place
• Protects Filaments
• Provides Transverse Strength
• Acts As A Load Transfer Medium
• Provides Interlaminar Toughness
• Provides Durability

8. Fiber/Matrix Bonding Quality and Resulting Failure Modes
Fiber/Matrix Bonding Quality and Resulting Failure Modes
Adhesive Failure – Undesirable Indicative of Weak Interfacial Bond Strength
Cohesive Failure – Desirable
Indicative of Strong Interfacial Bond Strength

9. Processes For Getting Resin Onto the Fiber
Processes For Getting Resin Onto the Fiber
Prepregging Unidirectional Fiber
Prepregging Machine
Infusing Preforms
Resin Film Infusion (RFI)
Resin Transfer Molding (RTM)
Vacuum Assisted Resin Transfer Molding (VARTM)

12. Solution Prepregging Using the Dip Tank Method
Solution Prepregging Using the Dip Tank Method

14. Prepregging Challenges
Prepregging Challenges
1) Proper tack over long period at RT
2) Proper drape over long period at RT
3) Acceptable RT out-time; good prepreg stability
4) Proper fiber/resin ratio
Parallel fiber alignment, minimum overlaps, splits, surface imperfections, hair balls
6) Solvent removal to acceptable level
7) 100% wet-out of filaments
8) Automated control to achieve reproducibility
9) Creel set-up and machine alignment

15. Vacuum Bag: Oven/Autoclave Cure

16. NASA Langley Research Center Autoclave
NASA Langley Research Center Autoclave
Capabilities
800°F
400 psi
24” x 48”

17. Autoclave state-of-the-art (Vought Aircraft; Charleston, SC)
Autoclave state-of-the-art
(Vought Aircraft; Charleston, SC)
- Inside working diameter: 30ft. (9.26M) Outside diameter: 32ft. (9.88M)
- Inside working length: 76 ft. (23.5M) Overall length: 112 ft. (34.5M)
- Vessel volume: 82,000 cu.ft Max temperature: 450F
- Max pressure: 150 psig Heating system: 40 million BTU
Control system: CPC Level III Weight: over 1,000,000 lbs.
- Man-hours to construct: 65,000+

18. Vacuum Assisted Resin Transfer Molding
Vacuum Assisted Resin Transfer Molding
Upper half of metal mold replaced by vacuum bag
Atmospheric pressure provides both the resin driving
force and the preform compaction force
Distribution medium is used to facilitate the resin flow
Typically a room temperature process
ROLE OF MATRIX
• BONDS AND HOLDS FILAMENTS IN PLACE
• PROTECTS FILAMENTS
• PROVIDES TRANSVERSE STRENGTH
• ACTS AS A LOAD TRANSFER MEDIUM
• PROVIDES INTERLAMINAR TOUGHNESS
• PROVIDES DURABILITY

19. Melt Viscosity of Comparison Materials
Melt Viscosity of Comparison Materials

20. Composite Fabrication: Technical Challenges
Composite Fabrication: Technical Challenges
Remove all air and volatiles so no porosity/voids
Debulk to desired and uniform net shape at all locations
on the part - full consolidation
Achieve proper fiber/resin ratio
Achieve reproducibility from part to part
Minimize warping and microcracking
Minimize scrappage and cold storage
Try for non-autoclave processing where possible
Be cost effective: automation; effective process models;
in-process control with in-line NDE; short cure cycles;
low part count; simple tooling

21. Summary
Polymer matrix composites are prepared by combining a matrix resin with fibers. The matrix resin bonds the fibers together and protects them. The fibers provide the capability to carry large loads efficiently. When the proper combination of matrix resin and fiber type is selected and a fabrication process resulting in a high quality composite is utilized, highly efficient and durable structures can be prepared with the required combination of properties for many different high performance applications.
MODIFIED COMPLETELY