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Thermoset Materials MFG 355. Introduction Thermoplastics vs Thermosets –Thermal properties –Strength –Uses –Processing.

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Presentation on theme: "Thermoset Materials MFG 355. Introduction Thermoplastics vs Thermosets –Thermal properties –Strength –Uses –Processing."— Presentation transcript:

1 Thermoset Materials MFG 355

2 Introduction Thermoplastics vs Thermosets –Thermal properties –Strength –Uses –Processing

3 Viscosity and Thermal Control during Crosslinking

4 General Properties of Thermosets Strength Flexibility Thermal Creep Ability to reinforce Ability to cure at room temperature

5 Formaldehyde Resins Phenolic Urea formaldehyde Melamine formaldehyde

6 Crosslinking Reactive GroupsPhenolics Phenol Formaldehyde Plus

7 Thermoset Types Phenolics

8 Crosslinking Reactive GroupsAmino plastics Amine Plus Formaldehyde

9 Amine plastics – clear adhesive Chipboard

10 Melamine Crosslinking as Polymers are Formed Three active sites Formaldehyde Plus

11 Crosslinking as Polymers are Formed Melamine Formaldehyde Water

12 Thermoset Types Melamine Plastics

13 Crosslinking as Polymers are Formed Melamine Formaldehyde Water

14 Polyester Thermosets (TS) or Unsaturated Polyesters (UP) Largest group of thermosets Most like to be reinforced with fiberglass

15 Initiator (usually peroxide) Carbon-carbon Double bond Crosslinking Reactive GroupsUnsaturated polyesters Plus

16 Thermoset Types Unsaturated Polyesters

17 Crosslinking Mechanism for Thermoset Polyesters Polyester Peroxide Styrene (large quantities)

18 Crosslinking – Heat Peroxide breaks apart

19 Crosslinking – Approach of styrene

20 Crosslinking – bond to styrene Half of peroxide bonds with other end of broken styrene molecule When styrene's double bond breaks, one end forms a free radical

21 Crosslinking – approach to polymer Styrene free radical causes the polymer's double bond to break and allows it to accept a new pi bond

22 Crosslinking– bonding to polymer Problems: Polymers not lined up, steric interference Solution: Styrene New bond New free radical

23 Crosslinking– approach of styrene

24 Crosslinking– activation of styrene Styrene's double bond opens, allowing two new free radical sites

25 Crosslinking – bonding of styrene Problems: Polymers still not lined up, steric interference Solution: Still more styrene New bondDouble bond opens but can't create a bond with any other open bond because of steric effects

26 Crosslinking – bonding of 2 nd styrene New bond Free radical

27 Crosslinking– bonding with 2 nd polymer Up to 8 styrenes might be needed in the bridge New bond

28 Crosslinking– bonding with 2 nd polymer Etc.

29 Crosslinking– more styrene

30

31 Crosslinking–bonding to 3 rd polymer

32 Laminating Resins

33 Additives to Thermoset Polyesters Fillers like Calcium Carbonate Tougheners like rubbers Antioxidants and UV stabilizers Reinforcements

34 Molding Compounds

35

36 Hardener (amine shown) Epoxy Rings Crosslinking Reactive GroupsEpoxies Plus

37 Thermoset Types Epoxies

38 Vinyl Esters (VE)

39 Polyimides Condensation Imide Carbon-carbon Double bond Imide React with addition reaction

40 Thermoset Types Imides

41 Crosslinking Reactive GroupsPolyurethanes Plus Polyols Diisocyanates

42 Thermoset Types Polyurethanes

43 Crosslinking Between two Existing Polymer Chains Polymerization Active Sites Crosslinking Active Site

44 Thank You


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