《通用高分子材料》课程教学课件（PPT讲稿）Chapter 2 General Plastics 2-3 Thermoset

2.3 Thermosetting plastics

2.3 Thermosetting plastics

General characteristicsHigh strength Low elongation High heat resistance High chemical resistance

• High strength • Low elongation • High heat resistance • High chemical resistance General characteristics

Table 1. Typical range of mechanical properties ofthermosetting plastics (filled or reinforced)TharmosettingFlexuralTensileElongationTensileCompressiveStrength/%Modulus,YieldMaterialsStrength,/MPa/MPa/MPastrength/MPa一470--70--20021880180--280Epoxy (molding420coumpound)5600--70--0.5--5100--350Unsaturated30--35050032400Polyester1350036--84Phenolics (cast-30--7070--230Resin)Urea-7200-70--40--1000.5--1180--35012010000formadehyde(moldingcompound)0.30.965--36--958000--150--320Melamine-16520000Formaldehyde

Thermosetting Materials Tensile Strength /MPa Elongation /% Tensile Modulus, /MPa Compressive Strength, /MPa Flexural Yield strength /MPa Epoxy (molding coumpound) 70-200 4 21880 180-280 70- 420 Unsaturated Polyester 30-350 0.5-5 5600- 32400 100-350 70- 500 Phenolics (cast￾Resin) 30-70 13500 70-230 36-84 Urea￾formadehyde （molding compound) 40-100 0.5-1 7200- 10000 180-350 70- 120 Melamine￾Formaldehyde 36-95 0.3—0.9 8000- 20000 150-320 65- 165 Table 1. Typical range of mechanical properties of thermosetting plastics (filled or reinforced)

Table2.Generalof propertiesof commercialthermosettingplastics(filledorreinforced)ThermosettingCoeff. ofResistanceWaterBurningRateMaterialThermoexp.to heat ℃absorption%10-5/℃(mm/min)EP0.3—1.40.05—0.2Self-ext150--260UP15500.3—1.4150--1800.01-1.0PF0.9—1.480--1500.12—0.36NegotiableUFSelf-ext0.6--1100-2100.40.8MF0.4—1.3Self-ext or100-2100.080.8no burning0.4—1.60.050.5Alkyd(醇酸树脂）Self-ext or150--240no burning

Thermosetting Material Burning Rate (mm/min) Coeff. of Thermo exp. 10-5 /℃ Resistance to heat ℃ Water absorption % EP Self-ext 0.3—1.4 150-260 0.05—0.2 UP 15—50 0.3—1.4 150-180 0.01-1.0 PF Negotiable 0.9—1.4 80-150 0.12—0.36 UF Self-ext 0.6-1 100-210 0.4—0.8 MF Self-ext or no burning 0.4—1.3 100-210 0.08—0.8 Alkyd(醇酸树脂） Self-ext or no burning 0.4—1.6 150-240 0.05—0.5 Table 2. General of properties of commercial thermosetting plastics（filled or reinforced）

Table 3.List of thermosetting plastics,properties and usesUsesThermosettingPropertiesplasticsMelamineStrong hard and heatPlastictableware,kitchenformaldehyderesistantworkshopPhenolHardand brittleCookwarehandleformaldehydeUreaElectrical fittingsTough, attractiveStrong whenPolyester resinCar bodies, boat hulls,reinforcedwithGFmolding such as bathsEpoxyAdhesives, castingTough and strongstructuralcomponents,coatings,laminating,and"potting"(encapsulationofotherpartswithinplastic)

Thermosetting plastics Properties Uses Melamine formaldehyde Strong hard and heat resistant Plastic tableware, kitchen workshop Phenol formaldehyde Hard and brittle Cookware handle Urea Tough, attractive Electrical fittings Polyester resin Strong when reinforced with GF Car bodies, boat hulls, molding such as baths Epoxy Tough and strong Adhesives, casting structural components, coatings, laminating, and "potting"(encapsulation of other parts within plastic). Table 3. List of thermosetting plastics, properties and uses

Table 4. Six tests to help identify plastics typePVC/uPVCAcrylicPolystyrenePhenolicPolyethyleneTest 1Can beVariousDarkClear ,Low or highAppearancegradesdensitycoloredplasticizedtranslucentToughed,Or opaquetransparentTest 2Can beShatterSome can beCan be cutShatterwhenRigiditycut with acut with awith a sharpwhen struckknifestrucksharpsharp knife,knifesomeshatterwhen struckDoesn'tTest 3Doesn'tPlasticizedToughenedBendingbendbendBending(Bendingbendingeasilyeasily)other doesn't

PVC/uPVC Polystyrene Polyethylene Phenolic Acrylic Test 1 Appearance Can be plasticized Various grades Toughed, transparent Low or high density Dark colored Clear , translucent Or opaque Test 2 Rigidity Can be cut with a sharp knife Some can be cut with a sharp knife, some shatter when struck Can be cut with a sharp knife Shatter when struck Shatter when struck Test 3 Bending Plasticized (Bending easily) Toughened bending other doesn’t Bending easily Doesn’t bend Doesn’t bend Table 4. Six tests to help identify plastics type

PhenolicPVC/uPVCAcrylicPolystyrenePolyethyleneTest 4Goes “floppy"Goes“floppyGoes‘floppyResists heat/Goes ‘floppyHeatingwhen heating/burningon heating/on heating/onandheating/candlewood smellfruity smellpungent smellmarigold smellsmellresultantsmellTest 5SelfDifficult toDense blackPlastic drips onBubbles andBurningburn, soot,smoke, melts,meltingextinguishingboils, blackswells &white smoke,bubbles atbits producedselfedgescracks whenheated.extinguishTest 6SinksSinksSinksFloatsSinksDensity

PVC/uPVC Polystyrene Polyethylene Phenolic Acrylic Test 4 Heating and resultant smell Goes “floppy” when heating/ pungent smell Goes ‘floppy’ on heating/ marigold smell Goes ‘floppy’ on heating/candle smell Resists heat/ burning wood smell Goes ‘floppy’ on heating/ fruity smell Test 5 Burning Difficult to burn, soot, white smoke, self extinguish. Dense black smoke, melts, bubbles at edges Plastic drips on melting Self extinguishing swells & cracks when heated. Bubbles and boils, black bits produced Test 6 Density Sinks Sinks Floats Sinks Sinks

2.3.1 Phenolics

2.3.1 Phenolics

OHOHOHCH20-RepeatnCH,OPF thermoset polymers

Synthesis:One stage ProcessTwo stage Process

Synthesis: ● One stage Process ● Two stage Process