高分子材料与应用英文版4Thermosets

1、高分子材料与应用英文版4ThermosetsChapter 4 Thermosets高分子材料与应用英文版4ThermosetsThermosets Resin Phenolics Epoxies Melamines Silicones Polyesters Composites Thermoset vs. thermoplastic高分子材料与应用英文版4ThermosetsGeneral Properties of Thermosets Strength Flexibility Thermal Creep Ability to reinforce Ability to cure at ro

2、om temperature高分子材料与应用英文版4ThermosetsFormaldehyde Resins Phenolics Urea formaldehyde Melamine formaldehyde高分子材料与应用英文版4ThermosetsCrosslinking of Phenolics Reactive GroupsPhenolics CCCCCCOHHHHHHPhenolCOHHFormaldehydePlus高分子材料与应用英文版4ThermosetsCompression MoldingCompression molding was specifically devel

3、oped for replacement of metal components with composite parts. The molding process can be carried out with either thermosets or thermoplastics. However, most applications today use thermoset polymers. In fact,compression molding is the most common method of processing thermosets.高分子材料与应用英文版4Thermose

4、tsResin Transfer Molding In the RTM process, dry (i.e.,unimpregnated ) reinforcement is pre-shaped and oriented into skeleton of the actual part known as the preform which is inserted into a matched die mold. The heated mold is closed and the liquid resin is injected The part is cured in mold. The m

5、old is opened and part is removed from mold.高分子材料与应用英文版4ThermosetsInjection MoldingGlass Reinforced Composites Plastic pellets with glass fibers are melted in screw, injected into a cold mold, and then ejected.Glass filled resin pellets高分子材料与应用英文版4ThermosetsApplication of Phenolics Wiring devices Sw

6、itch gear Circuit breakers Insulators Gears Wear guides Pulleys Rollers高分子材料与应用英文版4ThermosetsAmino Resins (UF and MF) Formaldehyde + -NH2(amine group) (1) Urea-formaldehyde (2) Melamine-formaldehyde高分子材料与应用英文版4ThermosetsCrosslinking Reactive GroupsAmino plasticsNHHRNHHAminePlusCOHHFormaldehyde高分子材料与

7、应用英文版4ThermosetsUrea formaldehyde高分子材料与应用英文版4ThermosetsMelamineCNCNCNNNNHHHHHHCrosslinking as Polymers are FormedThree active sitesFormaldehydeCOHHPlus高分子材料与应用英文版4ThermosetsCrosslinking as Polymers are FormedMelamine FormaldehydeWater高分子材料与应用英文版4ThermosetsCrosslinking as Polymers are FormedCNCNCNCNN

8、CNCNCNCNCNNCNCNCNCNNNCCNCNCNCNCNNCNCHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHMelamine FormaldehydeOHHWater高分子材料与应用英文版4ThermosetsAmine plastics clear adhesiveChipboard Applications: wood particleboard, plywood, boat hulls flooring furniture assemblies Cellulose-filled urea compound: Electrical wall plates

9、, receptacles, knobs, handle Cellulose-filled melamine compound: dinnerware, buttons, control buttons, knob高分子材料与应用英文版4ThermosetsApplication of melamine plastics Melamine Plastics高分子材料与应用英文版4ThermosetsPolyester Thermosets (TS) or Unsaturated Polyesters (UP) Largest group of thermosets Most like to b

10、e reinforced with fiberglass高分子材料与应用英文版4ThermosetsOOR1RInitiator(usually peroxide)CCR1RHHCarbon-carbonDouble bondCrosslinking Reactive GroupsUnsaturated polyestersPlus高分子材料与应用英文版4ThermosetsViscosity and Thermal Control during Crosslinking高分子材料与应用英文版4ThermosetsThermoset Types Unsaturated Polyesters高分

11、子材料与应用英文版4ThermosetsCrosslinking Mechanism for Thermoset PolyestersCCCCOOOOHHHHCCCCOOOOHHHHOOR1RPolyesterPeroxideStyrene(large quantities)CCCCHCHCHCHCHHHH高分子材料与应用英文版4ThermosetsCrosslinking HeatROHROHCCCCHCHCHCHCHHHHCCCCOOOOHHHHCCCCOOOOHHHHPeroxidebreaks apart高分子材料与应用英文版4ThermosetsCrosslinking Approa

12、ch of styreneROHROHCCCCHCHCHCHCHHHHCCCCOOOOHHHHCCCCOOOOHHHH高分子材料与应用英文版4ThermosetsCrosslinking bond to styreneROHCCCCHCHCHCHCHHHHHHROHCCCCOOOOHHHHCCCCOOOOHHHHHalf of peroxide bonds with other end of broken styrene moleculeWhen styrenes double bond breaks, one end forms a free radical高分子材料与应用英文版4Therm

13、osetsCrosslinking approach to polymerCCCCHCHCHCHCHHHHHHROHCCCCOOOOHHHHCCCCOOOOHHHHHHStyrene free radical causes the polymers double bond to break and allows it to accept a new pi bond高分子材料与应用英文版4ThermosetsCrosslinking bonding to polymerCCCCOOOOHHHHHHCCCCHCHCHCHCHHHHHHROHCCCCOOOOHHHHProblems: Polymer

14、s not lined up, steric interferenceSolution: StyreneCCCCHCHCHCHCHHHHNew bondNew free radical高分子材料与应用英文版4ThermosetsCrosslinking approach of styreneCCCCOOOOHHHHHHCCCCHCHCHCHCHHHHHHROHCCCCOOOOHHHHCCCCHCHCHCHCHHHH高分子材料与应用英文版4ThermosetsCrosslinking activation of styreneCCCCOOOOHHHHHHCCCCHCHCHCHCHHHHHHROH

15、CCCCHCHCHCHCHHHHHHCCCCOOOOHHHHStyrenes double bond opens, allowing two new free radical sites高分子材料与应用英文版4ThermosetsCrosslinking bonding of styreneCCCCOOOOHHHHHHCCCCOOOOHHHHHHCCCCHCHCHCHCHHHHHHROHCCCCHCHCHCHCHHHHHHProblems: Polymers still not lined up, steric interferenceCCCCHCHCHCHCHHHHSolution: Sti

16、ll more styreneNew bondDouble bond opens but cant create a bond with any other open bond because of steric effects高分子材料与应用英文版4ThermosetsCrosslinking bonding of 2nd styreneCCCCOOOOHHHHHHCCCCOOOOHHHHHHCCCCHCHCHCHCHHHHHHROHCCCCHCHCHCHCHHHHHHCCCCHCHCHCHCHHHHHHNew bondFree radical高分子材料与应用英文版4ThermosetsCr

17、osslinking bonding with 2nd polymerCCCCOOOOHHHHHHCCCCOOOOHHHHHHCCCCHCHCHCHCHHHHHHROHCCCCHCHCHCHCHHHHHHCCCCHCHCHCHCHHHHHHUp to 8 styrenes might be needed in the bridgeNew bond高分子材料与应用英文版4ThermosetsCrosslinking bonding with 2nd polymerCCCCOOOOHHHHHHCCCCOOOOHHHHHHCCCCHCHCHCHCHHHHHHROHCCCCHCHCHCHCHHHHHH

18、CCCCHCHCHCHCHHHHHHEtc.CCCCOOOOHHHHHH高分子材料与应用英文版4ThermosetsCrosslinking more styreneCCCCOOOOHHHHHHCCCCOOOOHHHHHHCCCCOOOOHHHHHHCCCCHCHCHCHCHHHHHHROHCCCCHCHCHCHCHHHHHHCCCCHCHCHCHCHHHHHHCCCCHCHCHCHCHHHHHH高分子材料与应用英文版4ThermosetsCrosslinking more styreneCCCCOOOOHHHHHHCCCCOOOOHHHHHHCCCCHCHCHCHCHHHHHHROHCCCC

19、HCHCHCHCHHHHHHCCCCHCHCHCHCHHHHHHCCCCHCHCHCHCHHHHHHCCCCHCHCHCHCHHHHHHCCCCOOOOHHHHHH高分子材料与应用英文版4ThermosetsCrosslinkingbonding to 3rd polymerCCCCOOOOHHHHHHCCCCOOOOHHHHHHCCCCOOOOHHHHHHCCCCHCHCHCHCHHHHHHROHCCCCHC HC HC HC HHHHHHCCCCHC HC HC HC HHHHHHCCCCHC HC HC HC HHHHHHCCCCHC HC HC HC HHHHHH高分子材料与应用英文版

20、4ThermosetsLaminating Resins高分子材料与应用英文版4ThermosetsAdditives to Thermoset PolyestersFillers like Calcium CarbonateTougheners like rubbersAntioxidants and UV stabilizersReinforcements高分子材料与应用英文版4ThermosetsGlass fiber reinforced plastics (GFRP)高分子材料与应用英文版4ThermosetsSheet Molding Compound (SMC)高分子材料与应用英

21、文版4ThermosetsSheet Molding Compound (SMC)高分子材料与应用英文版4ThermosetsRNNHHHHHardener(amine shown)CCORCCOHHHHHHEpoxy RingsEpoxies Reactive GroupsEpoxies Plus高分子材料与应用英文版4ThermosetsReaction schemes for the synthesis of DGEBA-type epoxy resinbisphenol A (DGEBA)高分子材料与应用英文版4ThermosetsThermoset Types Epoxies高分子材料与应用英文版4ThermosetsCrosslinking of Polyurethanes Reactive GroupsPolyuret