Thermoset Materials

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Thermoset Materials

• MFG 355

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Introduction

• Thermoplastics vs Thermosets
• Thermal properties
• Strength
• Uses
• Processing

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Viscosity and Thermal Control during Crosslinking
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General Properties of Thermosets

• Strength
• Flexibility
• Thermal
• Creep
• Ability to reinforce
• Ability to cure at room temperature

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Formaldehyde Resins

• Phenolic
• Urea formaldehyde
• Melamine formaldehyde

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Crosslinking

• Reactive GroupsPhenolics

Plus
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Thermoset Types

• Phenolics

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Crosslinking

• Reactive GroupsAmino plastics

Plus
Amine
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Amine plastics clear adhesive
Chipboard
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Crosslinking as Polymers are Formed
Plus
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Crosslinking as Polymers are Formed
Melamine Formaldehyde
Water
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Thermoset Types

• Melamine Plastics

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Crosslinking as Polymers are Formed
Water
Melamine Formaldehyde
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Polyester Thermosets (TS) or Unsaturated
Polyesters (UP)

• Largest group of thermosets
• Most like to be reinforced with fiberglass

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Crosslinking

• Reactive GroupsUnsaturated polyesters

Plus
Carbon-carbon Double bond
Initiator (usually peroxide)
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Thermoset Types

• Unsaturated Polyesters

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Crosslinking Mechanism for Thermoset Polyesters
Polyester
Styrene (large quantities)
Peroxide
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Crosslinking Heat
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Crosslinking Approach of styrene
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Crosslinking bond to styrene
When styrene's double bond breaks, one end forms
a free radical
Half of peroxide bonds with other end of broken
styrene molecule
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Crosslinking approach to polymer
Styrene free radical causes the polymer's double
bond to break and allows it to accept a new pi
bond
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Crosslinking bonding to polymer
New free radical
New bond
Problems Polymers not lined up, steric
interference
Solution Styrene
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Crosslinking approach of styrene
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Crosslinking activation of styrene
Styrene's double bond opens, allowing two new
free radical sites
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Crosslinking bonding of styrene
New bond
Double bond opens but can't create a bond with
any other open bond because of steric effects
Problems Polymers still not lined up, steric
interference
Solution Still more styrene
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Crosslinking bonding of 2nd styrene
Free radical
New bond
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Crosslinking bonding with 2nd polymer
Up to 8 styrenes might be needed in the bridge
New bond
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Crosslinking bonding with 2nd polymer
Etc.
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Crosslinking more styrene
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Crosslinking more styrene
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Crosslinkingbonding to 3rd polymer
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Laminating Resins
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Additives to Thermoset Polyesters
Fillers like Calcium Carbonate
Tougheners like rubbers
Antioxidants and UV stabilizers
Reinforcements
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Molding Compounds
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Molding Compounds
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Crosslinking

• Reactive GroupsEpoxies

Plus
Epoxy Rings
Hardener (amine shown)
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Thermoset Types

• Epoxies

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Vinyl Esters (VE)
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Polyimides
Carbon-carbon Double bond Imide
Condensation Imide
React with addition reaction
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Thermoset Types

• Imides

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Crosslinking

• Reactive GroupsPolyurethanes

Plus
Diisocyanates
Polyols
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Thermoset Types

• Polyurethanes

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Crosslinking Between two Existing Polymer Chains
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Thank You