Composites Test 1
-Combination of at least two components, a matrix/ reinforcements.
-This combination creates a material that has properties greater than or equal to the sum of the parts.
Isotropic vs. Anitropic
-Isotropic: Strength is the same in all directions.
-Anitropic: Strength is greatest in a certain direction.
Natural and Synthetic composites
-Synthetic: Plie wood, Carbon Fibers (man made)
Classification of Composites
Composed of layers or piles of matrix
Particles dispersed in the matrix
-Binder to the reinforcer
-Transfer loads across the structure
-Protects the reinforcement from outside environment
Major classes of Matrices
Considerations in determining proper matrix
Bond well with reinforcements
Sources of matrix
Starting material that is changed into a new material by means of further processing and use of additives.
Use of Thermoplastic polymers
Very brittle, high temperature resistant material. Can be the matrix only but in many cases is both the matrix and the reinforcer.
Use of Thermoset Polymers
Produced by combining a one-stage phenolic with melamine resin, not used for large volume applications and are generally produced in black or dark colors.
Co-polymer vs. Alloy
The combination of two or more monomers
The combination of two or more basic polymers into a mechanical mix
Various Thermoset polymers used in composites
Advantages of Thermoplastics in composites
-Ease of repairability
-Improved impact strength
-No need to refrigerate
-Much quicker processing time
Disadvantages of Thermoplastics in composites
-Overall lower high temperature properties
-Still some problems with fiber adherence
-Higher material cost
-Lack of tacticity/ flexibility in prepreg from
Advantages of Thermosets in composites
-Higher temperature properties
-Lower material cost
-Good fiber adherence
-Better tacticity/ flexibility
Disadvantages of Thermosets in composites
-Lower impact strength
-More difficult to repair
-Have to refrigerate
-Longer processing time
-Hard to recycle
Four methods of impregnating reinforcement to make prepreg
Composites Test 1
questions for first composites test