Final Prep

The degree of polymerization of a polypropylene with an average molecular weight of 126,000 is ___

126,000/42=3,000

The degree of polymerization of a polypropylene with an average molecular weight of 105,000 is ___

2500

The degree of polymerization of a polyethylene with an average molecular weight of 98,000 is ___

3500

For a film and sheet line using the roll stack process; the plastic sheet makes an S-wrap around the center roll and the bottom roll is called ___ operation. A. Downstack B. Upstack C. All stated answers are incorrect D. Roll stack

A

In the modulus vs temperature plot which of the following shows the presence of a rubbery plateau? A. High molecular weight polymers B. Crystalline polymers C. Highly cross linked polymers D. All stated answers are correct

A

Which of the following die would be used for the production of a polymer film with thickness of 0.4mm? A. T manifold die B. All stated answers are correct C. Horseshoe manifold die D. Coat hanger manifold die

B

Which of the following is not a component of a polymer extruder? A. Hopper B. Screw C. Die D. Barrel

C

"Two or more components are injected using the same runner and gate systems at different stages during the molding process" this statement is about ___ A. Co-injection molding B. Multi component injection molding C. Reaction injection molding D. Injection compression molding

A

A CaCO3 masterbatch would be classified as A. Filler masterbatch B. Color masterbatch C. All stated answers are incorrect D. Additive masterbatch

A

A remedy to rectify short shot defect is A. Both stated answers are correct B. Increase mold temperature C. Increase injection speed or pressure D. Both stated answers are incorrect

A

DSC cannot determine which of the following? A. Volatile content of materials B. Tm C. Tg D. Cure temperature

A

Degradation of extruded products can be reduced by A. All stated answers are correct B. Reducing time of plastic in the extruder C. Adding thermal stabilizer to the plastic D. Reducing extruder temperature

A

Motionless mixers through which the melt is pumped, rotated, and divided, leading to effective mixing without movable parts and mixing heads. The above statement describes which of the following? A. Static mixers B. Co-kneader C. Banbury mixer D. Maddock mixer

A

Rayleigh disturbances occurs in which of the following polymer blending mechanism? A. Dispersive mixing B. Coalescence C. All stated answers are incorrect D. Distributive mixing

A

The term for polymer crystal formation is called A. Spherulites B. Both stated answers are incorrect C. Chain folded structure D. Both stated answers are correct

A

Viscous material is modeled by ___ A. Dashpot which obeys Newton's laws B. Dashpot which obeys Newton's laws in series with a Hookean spring C. Hookean spring D. Maxwell model

A

What external factor has the most detrimental effect on polymeric materials? A. Ultraviolet radiation B. Extreme temperature C. Moisture D. All stated answers are incorrect

A

Which element of the mold leads from nozzle into the mold? A. Sprue B. Runners C. Gates D. Cold slug well

A

Which of the following accurately describes distributive mixing? A. Homogeneous spatial distribution of the minor component into the polymer matrix B. Combination of minor components to form larger agglomerate C. Break-up of the minor component of a mixture into smaller size particles or droplets D. All stated answers are incorrect

A

Which of the following accurately describes distributive mixing? A. Homogenous spatial distribution of the minor component into the polymer matrix B. Break-up of the minor component of a mixture into smaller size particles or droplets C. Combination of minor components to form larger agglomerates D. All stated answers are incorrect

A

Which of the following accurately describes the Maddock mixing section? A. All stated answers are incorrect B. Extruder with pins on the screw C. Extruder with wedged-shaped slots within the screw flights D. Extruder with adjustable pins on the barrel

A

Which of the following is not a complete polymer extrusion line for combination of materials via extrusion? A. Twin screw extruder B. Co extrusion C. Coating D. Lamination

A

Which of the following is not a feature of thermoplastics? A. All stated answers are incorrect B. Limited or no cross linking C. Can be easily reshaped or recycled D. Behave in plastic ductile manner

A

Which of the following is not true about extrudate swell? A. If drawdown is large enough it would increase extrudate swell B. All stated answers are incorrect C. Determined by the die design and the flow properties of the plastic D. It is often called die swell

A

Which of the following is not true for a ram extruder? A. Product output speeds are high B. Uses a reciprocating piston that forces material forward through the die C. UHMW PE can be used in ram extruders D. It is the least common extruder

A

Which of the following is part of the mold in an injection molding machine? A. Both stated answers are correct B. Both stated answers are incorrect C. Gate D. Sprue

A

Which of the following is true A. All stated answers are correct B. Samples that are slowly heated through Tg exhibit a lower Tg than those that are rapidly heated C. Cross linking elevates Tg D. Compared to molecular weight and composition Tg is relatively insensitive to pressure

A

Which of the following is true for most twin extruders? A. All stated answers are correct B. Most twin screw extruders for profile extrusion are counter-rotating extruders C. Most twin screw extruders are intermeshing D. Most twin screw extruders have parallel screws

A

Which of the following is true for stress relaxation? A. Polymer specimen is deformed by a fixed amount and the stress required to hold that amount of deformation is recorded over time B. Stress relaxation is temperature dependent but time independent C. Polymer specimen is subjected to a constant load and the amount of strain is recorded over time D. All stated answers are incorrect

A

With increase in temperature viscosity of thermosets and thermoplastics ___ A. All stated answers are incorrect B. Increases C. Does not change D. Decreases

A

___ is a polymer additive that is added to produce cellular polymers A. Blowing agent B. Flame retardant C. Anti static agent D. All stated answers are incorrect

A

___ is excess plastic around the area of the mold parting line on a molded part. A. Flash B. Blush C. Excessive warpage D. Short shot

A

___ is the science of fluid behavior during flow induced deformation A. Rheology B. Tribology C. Fluid mechanics D. Viscoelasticity

A

Die lines can be eliminated by A. Both stated answers are correct B. Both stated answers are incorrect C. Use longer die land D. Better vent port design

B

Elastic behavior is modeled by ___ A. Maxwell model B. Hookean spring C. Dashpot which obeys Newton's laws D. Dashpot which obeys Newton's laws in series with Hookean spring

B

Fluid memory contribution to die swell can be mitigated by ___ A. Increasing the first normal stress difference B. Lengthening the land length of the die C. Shortening the land length of the die D. Increasing the second normal stress difference

B

For a given polymer, which of the statements is true for the rate of crystallization? A. At melting temperature the net rate of crystallization is 0 B. Both stated answers are correct C. At the glass transition temperature the crystallization rate is 0 D. Both stated answers are incorrect

B

Polymerization that involves only monomer and a monomer soluble initiator is an example of which polymerization technique? A. Emulsion polymerization B. Bulk polymerization C. All stated answers are incorrect D. Solution polymerization

B

Spider legs are present in which of the following dies? A. None of the stated answers are correct B. Extrusion die for hollow shapes C. Flat sheet coat hanger manifold die D. Extrusion die for solid cross section

B

The factor responsible for changing the shape and dimensions of the plastic as it emerges from the die is A. Both stated answers are incorrect B. Both stated answers are correct C. Drawdown D. Die swell

B

The main task of the plasticating unit of the injection molding machine is to A. Melt the polymer B. Both stated answers are correct C. Inject the melt into the cavity D. Both stated answers are incorrect

B

The shape of extrudate under melt fracture where waves appear in the extrudate is called ___ A. All stated answers are incorrect B. Shark skin C. Stick-slip D. Spurt flow

B

What determines the cross sectional shape of polymer extruder products? A. Breaker plate B. Die C. Screw D. Barrel

B

Which is the advantage of hydraulic clamping? A. It transmits its maximum closing force when the system is fully extended B. The system can take different mold sizes without major system adjustments C. Both stated answers are incorrect D. Both stated answers are correct

B

Which model accurately represents the shear thinning region in the viscosity vs strain rate curve? A. Maxwell model B. Power law model C. WLF equation model D. Dashpot model

B

Which of the following has the lowest Tg? A. PS B. PE C. PVC D. PP

B

Which of the following is a technique to combine different materials to form multi layered plastic film/sheet? A. Twin screw extrusion B. Coextrusion C. Both stated answers are incorrect D. Both stated answers are correct

B

Which of the following is not true for amorphous polymers A. All stated answers are incorrect B. They could have 50% amorphous regions C. They are very clear/transparent D. Polymer chains are randomly arranged

B

Which of the following is not true for the metering zone of the extruder? A. All stated answers are incorrect B. The solid polymer particles are compacted and form a solid plug that spirals along the length of the screw channel C. Region where all plastic is completely melted D. It generates pressure sufficient for pumping

B

Which of the following statement is true about the hot-runner mold? A. Solidifies sprue efficiently B. Both stated answers are incorrect C. Solidifies runner efficiently D. Both stated answers are correct

B

Which of the following statements is true about gel point? A. The point where the curing thermoset become a highly interconnected network B. Both stated answers are correct C. Is the degree of cure when the molecular weight goes to infinity D. Both stated answers are incorrect

B

Which one of the following polymer processing techniques has the highest shear rates? A. Calendaring B. Fiber spinning C. Extrusion D. Injection molding

B

__ is the science of fluid behavior during flow induced deformation? A. Fluid mechanics B. Rheology C. Viscoelasticity D. Tribology

B

"A mold compression action to compact the polymer material for producing parts with dimensional stability and surface accuracy" this statement is about ___ A. Reaction injection molding B. Co-injection molding C. Injection compression molding D. Multi component injection molding

C

A polymeric material usually consists of polymer chains of various lengths giving rise to different molecular weight terminologies. For a given polymer sample which of the following molecular weight would be the lowest (smallest) value? A. Viscosity average molecular weight B. Weight average molecular weight C. Number average molecular weight D. Median average molecular weight

C

A single screw extruder with pins on the barrel and a screw that oscillates in the axial direction. Which of the following accurately describes the above statement? A. All stated answers are incorrect B. CRD mixer C. Co-kneader D. Static mixer

C

For a small tubing extruder line which of the following is used to determine/control the wall thickness? A. Cutter speed B. Both stated answers are correct C. Puller speed D. Both stated answers are incorrect

C

In the following formulation which of the following component would constitute to be the major component in a polymer blend/mix? A. Color filament B. Filler powder C. Plastic pellet D. UV stabilizer droplets

C

In the morphology development of a polymer blend which of the following mechanism is not a contributing factor? A. Dispersive B. Distributive C. All stated answers are incorrect D. Coalescence

C

Isometric creep plots generated by ___ A. By plotting strain over time at a constant stress load B. By cutting sections through the creep curves at constant times and plotting the stress as a function of strain C. By taking constant strain sections of the creep curves and by plotting stress versus time D. By plotting stress load over time at constant strain

C

Surface of the finished part separates or appears to be composed of layer of solidified resin. Strata or fish scale type appearance where the layers may be separated. This statement describes which of the following defect of an injection molded part? A. Warpage B. Flash C. Delamination D. Weld lines

C

The shape extradite under melt fracture where waves appear in the extradite is called ___ A. All stated answers are incorrect B. Stick-slip C. Shark skin D. Spurt flow

C

What is a measure of the internal friction of a fluid when velocity gradients are present in the fluid? A. Plasticity B. Turbidity C. Viscosity D. Fluidity

C

When was the first single-screw extruded designed for the processing of thermoplastic polymers built? A. 1930 B. 1948 C. 1935 D. 1938

C

Which of the following die would be used for the production of a polymer film with thickness of 0.4mm? A. T manifold die B. Coat hanger manifold die C. All stated answers are correct D. Horseshoe manifold die

C

Which of the following is a feature of thermosets? A. Can be easily reshaped or recycled B. Large elastic deformation C. Highly cross linked structure D. Behave in plastic ductile manner

C

Which of the following is an example of a copolymer? A. SBR B. ABS C. Both stated answers is correct D. Both stated answers are incorrect

C

Which of the following is not a main element of a complete extrusion product line? A. Cutter or saw B. Calibrating device C. Hopper D. Cooling device

C

Which of the following is not a type of polymer extruder? A. Ram extruder B. Twin screw extruder C. Twin ram extruder D. Single screw extruder

C

Which of the following is not an example of a polymer synthesis mechanism? A. Condensation polymerization B. Ionic polymerization C. Nucleophilic addition polymerization D. Free radical polymerization

C

Which of the following is not true for polymer melts? A. All stated answers are incorrect B. They are temperature dependent C. They are shear thickening D. They are viscoelastic

C

Which of the following is true about the time temperature superposition temperature? A. Tests at various temperatures can be used to assemble a master curve at one of the test temperatures B. Stress relaxation is temperature dependent C. All stated answers are correct D. Stress relaxation is time dependent

C

Which of the following is true for most twin screw extruders? A. Most twin extruders for profile extrusion are counter-rotating extruders B. Most twin extruders are intermeshing C. All stated answers are correct D. Most twin extruders have parallel screws

C

Which of the following shear rate (1/s) would be typical of injection molding? A. 20 B. 20,000 C. 2,000 D. 200

C

Which of the following statements is true? A. Increasing temperature will result in more ductile behavior for thermoplastic polymers B. Exact nature of the tensile response depends on mol wt, mol wt distribution, crystallinity, extent or cross linking and branching C. All stated answers are correct D. Increasing strain rate substantially will result in a brittle failure

C

___ is a polymer additive that is added to alter the polymer rheological and flow properties A. Blowing agent B. Anti static agent C. Plasticizer D. All stated answers are incorrect

C

A filler can be added to the polymer for which of the following reasons? A. To reduce cost B. To reduce the amount of resin to produce a part C. To enhance mechanical properties D. All stated answers are correct

D

For polymer solution: 1) C* is the concentration that transitions from extremely dilute solution and 2) C is the concentration where the coils become entangled. Identify the region where there is the highest abrupt increase in relative viscosity. A. C>C* B. C*<C<C C. C<C** D. C=C*

D

In the morphology development of a polymer blend which of the following mechanism is not a contributing factor? A. Dispersive B. Distributive C. Coalescence D. All stated answers are incorrect

D

Inability of two melt fronts to knit together in a homogeneous fashion during the mounding process, resulting in weak areas in the part of varying severity. This statement describes which of the following defect of an injection molded part? A. Flow lines B. Jetting C. Warpage D. All stated answers are incorrect

D

Motionless mixers through which the melt is pumped, rotated, and divided, leading to effective mixing without movable parts and mixing heads. The above statement describes which of the following? A. Banbury mixer B. Co-kneaded C. Maddock mixer D. Static mixer

D

PE-LLD is an acronym for A. Polyethylene-Lactide Low Density B. All stated answers are correct C. Polyethylene-Lignin Low Density D. Polyethylene-Linear Low Density

D

Polymerization that involves only monomer and a monomer soluble initiator is an example of which polymerization technique? A. All stated answers are correct B. Soluble Polymerization C. Emulsion Polymerization D. Bulk Polymerization

D

The melt strand enters the cavity in an uncontrolled way. Due to cooling down, the strand is not fused homogeneously with the melt that follows and it shows as a serpentine line on the part surface. This statement describes which of the following defect of an injection molded part? A. Flow lines B. Weld lines C. Warpage D. Jetting

D

The rack and pinion system is a part of which of the following injection molding machine? A. All stated answers are incorrect B. Plunger type injection molding machine C. The reciprocating screw type injection molding machine D. Hand injection molding machine

D

The viscosity of a reinforced polymer during processing is affected by A. Viscosity of the suspending polymer B. Volume fraction of suspended particles C. Both stated answers are incorrect D. Both stated answers are correct

D

When was the first single-screw extruder designed for the processing of thermoplastic polymers built? A. 1930 B. 1938 C. 1948 D. 1935

D

Which of the following accurately describes dispersive mixing? A. Combination of minor components to form larger agglomerates B. All stated answers are incorrect C. A homogeneous spatial distribution of the minor component into the polymer matrix D. Break-up of the minor component of a mixture into smaller size particles or droplets

D

Which of the following accurately describes the QSM extruder? A. All stated answers are incorrect B. Extruder with pins on the screw C. Extruder with wedge-shaped slots within the screw flights D. Extruder with adjustable pins on the barrel

D

Which of the following is a thermoplastic? A. Polybutadiene B. All stated answers are incorrect C. Epoxy D. Polysyrene

D

Which of the following is a true statement that describes the dependence of mol wt and composition on Tg? A. Both stated answers are incorrect B. Tg decreases with increase in mol wt at low mol wt range C. Both stated answers are correct D. Tg of the mixture depends on the amount of each component

D

Which of the following is not a component of a polymer extruded? A. Screw B. Hopper C. Barrel D. Die

D

Which of the following is not true about breaker plate? A. It is a thick metal disk with closely spaced holes B. All stated answers are incorrect C. It is located at the end of the barrel D. They are used to trap contaminants

D

Which of the following is not true for secondary relaxation process? A. All stated answers are correct B. They involve limited motion of the main chain C. The occur below Tg D. They are large scale molecular motions that occur in the amorphous glassy state

D

Which of the following is the most common type of multi screw extruder? A. Twin ram extruder B. Tetra screw extruder C. All stated answers are incorrect D. Twin screw extruder

D

Which of the following is true about the Boltzmann Superposition Principle? A. The stress within a polymer specimen that is exposed to several strains at different points in time is the sum of all stress responses B. Deformation of a polymer component is the sum of all strains that result from various loads acting on the part at different times C. Both stated answers are incorrect D. Both stated answers are correct

D

Which of the following is true for non-intermeshing twin screw extruder? A. They avoid problems due to metal to metal contact between screws B. They have limited dispersive mixing capability C. L/D ratio can be 150:1 D. All stated answers are correct

D

Which of the following product cannot be formed by extrusion process? A. Sheet B. Pipe C. Coated electrical wire D. Egg cartons

D

Which of the following shear rate (1/s) would be typical of compression molding? A. 50 B. 75 C. 25 D. All stated answers are correct

D

Which one of the following polymer processing technique has the lowest shear rates? A. Compression molding B. Calendaring C. Both stated answers are incorrect D. Both stated answers are correct

D