PSE322 , PSE 322 QUIZ 11 QUESTIONS & ANSWERS
What kind of wet web of paper gives the best dewatering in response to vacuum? -
Answers :Highly uniform
What happens if a fiber suspension has been treated with a cationic acrylamide
copolymer (retention aid) and then subjected to a high level of hydrodynamic shear (as
in a blender)? - Answers :INCORRECT
The fiber flocs break up but then form again almost to the same degree when the level
of hydrodynamic shear decreases.
The degree of fiber flocculation reverts to the level prior to polymer addition.
What two things work to hold a floc of papermaking fibers together in a water
suspension even in the absence of chemical flocculating agents? - Answers :Elastic
forces and friction
What is the expected effect of dissolved an colloidal substances on the performance of
cationic strength agents added at the wet end? - Answers :A higher dosage required
What type of high-charge cationic additive is inorganic and is most effective at pH
values below about 5.5? - Answers :Papermakers' alum
Which of the following is a major source of anionic dissolved and colloidal substances,
especially in some mechanical pulp systems? - Answers :Peroxide bleaching
Increasing salt has been shown to have what effect on adsorption of cationic starch
onto cellulosic fibers? - Answers :The adsorbed amount decreased with increasing salt.
Why does the streaming potential decay (it becomes more negative or less positive) in
the minutes after addition of a cationic polymer? - Answers :The polymer diffuses into
pores in the fiber cell walls and also tends to lie down flatter on the surfaces.
How does increasing salt concentration tend to affect streaming current titration
endpoints? - Answers :The apparent cationic demand first gradually shifts to higher
levels and then cannot be detected any more.
What is the role of the streaming current with respect to cationic demand
determinations? - Answers :The endpoint is reached when the signal goes to zero.
When a retention aid is used in a papermaking furnish that contains fibers, cellulosic
fines, and mineral filler particles, what happens when the treated furnish is subjected to
high shear, comparable to that of a kitchen-type blender? - Answers :Filler particles
often remain attached to the fibers.
,In the equation for crowding factor, what is the meaning of the meaning of the term
"L/D"? - Answers :The aspect ratio
Why is there a connection between dewatering rates and formation uniformity? -
Answers :Slow dewatering forces a higher headbox consistency, which gives a higher
crowding factor.
How do dissolved and colloidal anionic substances affect a dissolved cationic strength
agent? - Answers :The strength agent becomes neutralized in charge.
When latex from coated broke gets sent back to the paper machine, what does it
contribute? - Answers :Anionic charge (DCS)
What type of additive can effectively form complexes to avoid some adverse effects of
excessive levels of dissolved and colloidal cationic substances? - Answers :High-charge
cationic
What does the term "microelectrophoresis" refer to? - Answers :A way to evaluate the
zeta potential of small particles in an aqueous suspension
The binding between what and the toluidine blue dye causes the color to change from
blue to pink? - Answers :Polyvinylsulfate, potassium salt
How does increasing salt affect the effectiveness of a cationic retention aid? - Answers
:Lower efficiency
What is the color of the endpoint of a colorimetric titration, when using toluidine blue
dye? - Answers :Purple-pink
When Britt and Unbehend tested gravity dewatering, which additive or additives gave
the most rapid release of water? - Answers :PEI followed by aPAM
In the equation for crowding factor, what is the meaning of the parameter "C(v)", where
"v" is ordinarily shown as a subscript when proper notation is possible? - Answers
:Volume concentration
Which of the following results in fast initial drainage but poor response to vacuum
dewatering? - Answers :Flocculated fibers in the wet web
What type of dissolved and colloidal substances can be effectively dealt with by addition
of pectinase enzyme? - Answers :Hemicellulose byproducts released by peroxide
bleaching
What operation can be effective in reducing the amount of dissolved and colloidal
substances passing from kraft pulping to a paper machine system producing an
unbleached kraft paper or paperboard grade? - Answers :Washing of the pulp
,Papermakers who blend pulps of different types may want to know which type of pulp
typically contributes the most to the dissolved and colloidal substances (DCS). What
related quantity are they often concerned about? - Answers :Which pulp type
contributes the most variability of DCS
When does the titrant begin to affect the signal of a SC device during evaluation of
cationic demand? - Answers :When the titrant molecules begin to adsorb onto the
plastic surfaces
What can be measured directly, without requiring a calculation, by imposing a pressure
differential across a fiber pad submerged in water and having electrode probes on both
sides? - Answers :Streaming potential
What factors need to be considered when calculating zeta potential based on streaming
potential data? - Answers :Viscosity, conductivity, and pressure difference
When using a colorimetric endpoint for determinations of cationic demand (toluidine
blue dye), what color corresponding to an excess of cationic surface and colloidal
charge? - Answers :Blue
When Britt and Unbehend tested vacuum dewatering, which additive or additives gave
the most rapid release of water? - Answers :Untreated (blank condition)
What is the principle of selective detachment? - Answers :The hydrodynamic shear
needed to separate the fibers is expected to be less than the shear needed to detach a
fine particle from a fiber, if the retention aid treatment is kept constant.
What two addition points are usually recommended for a very-high-mass cationic
acrylamide copolymer? - Answers :Before or after the pressure screen
A large overdose of cationic additives in a paper machine system can result in what? -
Answers :Cationic polymer remaining in solution
The cationic demand of a process water sample from a paper mill is directly proportional
to what? - Answers :The volume of titrant (poly-DADMAC)
What has to contain a water-insoluble surfactant having a low viscosity? - Answers :A
defoamer formulation
What tends to cause deposits, reduced paper strength, and difficulties with hydrophobic
sizing? - Answers :Too much defoamer
Which of the following is true about an "oil-free" defoamer agent? - Answers :It contains
100% of actives and particulates.
, What type of rheology is similar to having a yield stress, without actually having a
definable yield stress? - Answers :Pseudo-plastic
What type of fluid develops very high resistance to flow at the highest levels of shear
rate? - Answers :Dilatent
Which of the following is not classified as an "additive" for a coating formulation? -
Answers :Plastic pigment
Which type of starch product commonly used in coating formulations is also well suited
for wet-end addition? - Answers :None of them
Why are steps usually taken to decrease the molecular mass and viscosity of starch
before it is used in coatings? - Answers :To facilitate flow at high shear during coating
What is the function of acrylic acid monomer unit in an acrylic latex product? - Answers
:Confer alkali-swellability
Protein binder has limited shelf life, odor issues, and relatively high cost. So what is the
most important advantage of using a protein binder? - Answers :Improved adhesion
What two factors generally will determine whether or not a paper wet web will break
when subjected to stress and strain? - Answers :INCORRECT
Solids content and entrained air content
Increasing the solids content of a wet web, while keeping everything else the same, will
cause what changes? - Answers :INCORRECT
Higher stretch to breakage and higher wet tensile strength
A centrifugal degasser (POMP) achieves what? - Answers :Separation of process water
from entrained air
What attributes of a coating are important when the base sheet is too dark or too non-
uniform in color? - Answers :Coverage and opacity
How do coating pigments characteristically differ from wet-end fillers of the same
general chemical composition? - Answers :They are smaller.
Which of the following is classified as a binder in a coating formulation? - Answers
:Latex
Which of the following is classified as a pigment in a coating formulation? - Answers
:Kaolin clay
What kind of wet web of paper gives the best dewatering in response to vacuum? -
Answers :Highly uniform
What happens if a fiber suspension has been treated with a cationic acrylamide
copolymer (retention aid) and then subjected to a high level of hydrodynamic shear (as
in a blender)? - Answers :INCORRECT
The fiber flocs break up but then form again almost to the same degree when the level
of hydrodynamic shear decreases.
The degree of fiber flocculation reverts to the level prior to polymer addition.
What two things work to hold a floc of papermaking fibers together in a water
suspension even in the absence of chemical flocculating agents? - Answers :Elastic
forces and friction
What is the expected effect of dissolved an colloidal substances on the performance of
cationic strength agents added at the wet end? - Answers :A higher dosage required
What type of high-charge cationic additive is inorganic and is most effective at pH
values below about 5.5? - Answers :Papermakers' alum
Which of the following is a major source of anionic dissolved and colloidal substances,
especially in some mechanical pulp systems? - Answers :Peroxide bleaching
Increasing salt has been shown to have what effect on adsorption of cationic starch
onto cellulosic fibers? - Answers :The adsorbed amount decreased with increasing salt.
Why does the streaming potential decay (it becomes more negative or less positive) in
the minutes after addition of a cationic polymer? - Answers :The polymer diffuses into
pores in the fiber cell walls and also tends to lie down flatter on the surfaces.
How does increasing salt concentration tend to affect streaming current titration
endpoints? - Answers :The apparent cationic demand first gradually shifts to higher
levels and then cannot be detected any more.
What is the role of the streaming current with respect to cationic demand
determinations? - Answers :The endpoint is reached when the signal goes to zero.
When a retention aid is used in a papermaking furnish that contains fibers, cellulosic
fines, and mineral filler particles, what happens when the treated furnish is subjected to
high shear, comparable to that of a kitchen-type blender? - Answers :Filler particles
often remain attached to the fibers.
,In the equation for crowding factor, what is the meaning of the meaning of the term
"L/D"? - Answers :The aspect ratio
Why is there a connection between dewatering rates and formation uniformity? -
Answers :Slow dewatering forces a higher headbox consistency, which gives a higher
crowding factor.
How do dissolved and colloidal anionic substances affect a dissolved cationic strength
agent? - Answers :The strength agent becomes neutralized in charge.
When latex from coated broke gets sent back to the paper machine, what does it
contribute? - Answers :Anionic charge (DCS)
What type of additive can effectively form complexes to avoid some adverse effects of
excessive levels of dissolved and colloidal cationic substances? - Answers :High-charge
cationic
What does the term "microelectrophoresis" refer to? - Answers :A way to evaluate the
zeta potential of small particles in an aqueous suspension
The binding between what and the toluidine blue dye causes the color to change from
blue to pink? - Answers :Polyvinylsulfate, potassium salt
How does increasing salt affect the effectiveness of a cationic retention aid? - Answers
:Lower efficiency
What is the color of the endpoint of a colorimetric titration, when using toluidine blue
dye? - Answers :Purple-pink
When Britt and Unbehend tested gravity dewatering, which additive or additives gave
the most rapid release of water? - Answers :PEI followed by aPAM
In the equation for crowding factor, what is the meaning of the parameter "C(v)", where
"v" is ordinarily shown as a subscript when proper notation is possible? - Answers
:Volume concentration
Which of the following results in fast initial drainage but poor response to vacuum
dewatering? - Answers :Flocculated fibers in the wet web
What type of dissolved and colloidal substances can be effectively dealt with by addition
of pectinase enzyme? - Answers :Hemicellulose byproducts released by peroxide
bleaching
What operation can be effective in reducing the amount of dissolved and colloidal
substances passing from kraft pulping to a paper machine system producing an
unbleached kraft paper or paperboard grade? - Answers :Washing of the pulp
,Papermakers who blend pulps of different types may want to know which type of pulp
typically contributes the most to the dissolved and colloidal substances (DCS). What
related quantity are they often concerned about? - Answers :Which pulp type
contributes the most variability of DCS
When does the titrant begin to affect the signal of a SC device during evaluation of
cationic demand? - Answers :When the titrant molecules begin to adsorb onto the
plastic surfaces
What can be measured directly, without requiring a calculation, by imposing a pressure
differential across a fiber pad submerged in water and having electrode probes on both
sides? - Answers :Streaming potential
What factors need to be considered when calculating zeta potential based on streaming
potential data? - Answers :Viscosity, conductivity, and pressure difference
When using a colorimetric endpoint for determinations of cationic demand (toluidine
blue dye), what color corresponding to an excess of cationic surface and colloidal
charge? - Answers :Blue
When Britt and Unbehend tested vacuum dewatering, which additive or additives gave
the most rapid release of water? - Answers :Untreated (blank condition)
What is the principle of selective detachment? - Answers :The hydrodynamic shear
needed to separate the fibers is expected to be less than the shear needed to detach a
fine particle from a fiber, if the retention aid treatment is kept constant.
What two addition points are usually recommended for a very-high-mass cationic
acrylamide copolymer? - Answers :Before or after the pressure screen
A large overdose of cationic additives in a paper machine system can result in what? -
Answers :Cationic polymer remaining in solution
The cationic demand of a process water sample from a paper mill is directly proportional
to what? - Answers :The volume of titrant (poly-DADMAC)
What has to contain a water-insoluble surfactant having a low viscosity? - Answers :A
defoamer formulation
What tends to cause deposits, reduced paper strength, and difficulties with hydrophobic
sizing? - Answers :Too much defoamer
Which of the following is true about an "oil-free" defoamer agent? - Answers :It contains
100% of actives and particulates.
, What type of rheology is similar to having a yield stress, without actually having a
definable yield stress? - Answers :Pseudo-plastic
What type of fluid develops very high resistance to flow at the highest levels of shear
rate? - Answers :Dilatent
Which of the following is not classified as an "additive" for a coating formulation? -
Answers :Plastic pigment
Which type of starch product commonly used in coating formulations is also well suited
for wet-end addition? - Answers :None of them
Why are steps usually taken to decrease the molecular mass and viscosity of starch
before it is used in coatings? - Answers :To facilitate flow at high shear during coating
What is the function of acrylic acid monomer unit in an acrylic latex product? - Answers
:Confer alkali-swellability
Protein binder has limited shelf life, odor issues, and relatively high cost. So what is the
most important advantage of using a protein binder? - Answers :Improved adhesion
What two factors generally will determine whether or not a paper wet web will break
when subjected to stress and strain? - Answers :INCORRECT
Solids content and entrained air content
Increasing the solids content of a wet web, while keeping everything else the same, will
cause what changes? - Answers :INCORRECT
Higher stretch to breakage and higher wet tensile strength
A centrifugal degasser (POMP) achieves what? - Answers :Separation of process water
from entrained air
What attributes of a coating are important when the base sheet is too dark or too non-
uniform in color? - Answers :Coverage and opacity
How do coating pigments characteristically differ from wet-end fillers of the same
general chemical composition? - Answers :They are smaller.
Which of the following is classified as a binder in a coating formulation? - Answers
:Latex
Which of the following is classified as a pigment in a coating formulation? - Answers
:Kaolin clay
