Fundamentals of Fiber Modification Chemistry

Fundamentals of Fiber

Modification Chemistry

Art J. Ragauskas, Yunqiao Pu, Lenong AllisonInstitute of Paper Science and Technology

School of Chemistry and BiochemistryGeorgia Institute of Technology

“If you want to succeed, you should strike out on new paths rather than travel the worn paths of accepted success.” – John D. Rockefeller

Process Research Publications: +140,000

Product-Platform Research Publications: ~9,000

Fundamentals of Fiber Modification Chemistry:Promising Research Patterns

• Main group responsible for surface and bulk charge of kraft fibers.

• Important for pulp swelling.

• Increase pulp fiber softness and collapsibility.

• Improve pulp strength properties.

• Improve beatability.

• Capable of ion-exchange reactions.

Fundamentals of Fiber Modification Chemistry: Importance of Carboxylate Groups

COO

OOC COO

COO

COOH

HOOC

[-COOH]Kspecific =[-COO ][H ]

Fundamentals of Fiber Modification Chemistry:Grafting - Acrylic Acid Groups

Lignin

OH

OCH3

(NH4)2Ce(NO3)6

CO2Me OH

H3COOCH3

O

OH

H3COOH

ONaOH

Pulp [Acid] meq/g

WRV H2O g/od pulp

Tear IndexmNm2/g

Burst Index kPam2/g

TMP 0.083 1.9

2.8 1.1

Low Graft

0.146 2.3 2.8 2.3

High Graft

0.184 2.6 3.0 3.2

Fundamentals of Fiber Modification Chemistry:Grafting - Acrylic Acid Groups

Fundamentals of Fiber Modification Chemistry:Grafting – Cationized Fibers

+

+

+

SW Mechanical

Linerboard Pulp

NaOH

ON Cl

HO

O

OH

OH

OCH3

OCH3

Fundamentals of Fiber Modification Chemistry:Cationized SGW-Tear Index

0

0.5

1

1.5

2

Tea

r In

dex SGW

SGW-0.07%NSWG-0.10%NSWG-0.12%NSWG-0.19%N

0

5

10

15

20

Ten

sile

Inde

x SGWSGW-0.07%NSWG-0.10%NSWG-0.12%NSWG-0.19%N

Fundamentals of Fiber Modification Chemistry:Cationized SGW-Linerboard Tensile Index

8

9

10

11

12

13

Ten

sile

Inde

x

Linerboard Linerboard-Graft1Linerboard-Graft2

You Want to Put What in My Pulp Mill?!@#%

Need to Address

- Cost:Benefit- Waste treatment- What kind of grafting reactor will you use at 1000 tons/day

Fundamentals of Fiber Modification Chemistry: Topochemistry of Acid Groups -ECF SW Kraft Pulp

0.2

0.6

1

1 2 3 4 5

Position

BLANK

BULK

SURFACE

Lumen

[-C

OO

- ]Experimental: Grafted acid groups on holocellulose,

controlling topochemistry

SEM

Barzyk, Page, and Ragauskas (1996)

Fundamentals of Fiber Modification Chemistry: Topochemistry of Acid Groups -ECF SW Kraft Pulp

0

0.05

0.1

0.15

0.2

0.25

170 220 270 320 370

Light Scattering Coefficient (cm 2/ g)

BLANK

BULK

SURFACE

Scott- Bond (J)

Conclusion: Surface acid groups yield unique strength properties

Fundamentals of Fiber Modification Chemistry:

Fiber Acid Groups: Key parameter to enhance fiber-fiber bonding, swelling, wet-end chemical retention

0

1

2

3

4

5

170 220 270 320 370

Light Scattering Coefficient (cm2/ g)

BLANK

BULK

SURFACE

Bre

akin

g L

engt

h (k

m)

Light Scattering (cm2/g)

Barzyk, Page, and Ragauskas (1996)

C O–

O

Attachment of CMC onto Kraft ECF Fiber (Lindstrom, 2000)- pH 8, 0.05 M CaCO3, csc 2.5%, 120oC, 2h - 1 – 4% charge

Current Pulp Mill

Status

Fiber Modification: Fiber Charge - Mill Status

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

Kraft-C

(SW

)Kraf

t-C (S

W)

Kraft-C

(SW

(PS/AQ))

Kraft-C

(SW

)Kraf

t-C (S

W)

Kraft-C

(SW

)

Kraft-C

(Euc

alyptu

s)Kraf

t-C (S

W)

Sulfite

Sulf

ite

Kraft-C

(SW

post-

D2)

Acid

con

tent

(meq

/gr)

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

Kraft-A Kraft-A Kraft-A Kraft-A Kraft-A Kraft-A Kraft-B Kraft-B

Acid

con

tent

(meq

/gr)

Little, if any, control of Fiber charge 0.016 – 0.07 meq/gr

Fiber resource only current control mechanism

50

55

60

65

70

75

80

85

90

95

100

Refere

nce C

ookBro

wn StockO2 F

eedO2 W

asher M

atD0 M

at(E

OP) Mat

D1 Mat

(R1-3

)*

D1 Transfe

r (R1-3)

*D1 M

at (R

4)*

D1 Transfe

r (R4)*

Stage

Tens

ile In

dex

0

20

40

60

80

100

120

Aci

d C

onte

nt, µ

eq/g

Tensile IndexBulk Acid

Fundamentals of Fiber Modification: Mill Status

• OD(EOP)D Mill Tensile Strength and Bulk/Surface Acid Groups

peroxide

Gradual loss of acid groups due in partto degradation of lignin

Finally P increases BrightnessStrength-acid groups

Fundamentals of Fiber Modification: Mill Status

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Kraft-A Kraft-A Kraft-A Kraft-A Kraft-A Kraft-A Kraft-B Kraft-B

Cu

#

0

0.5

1

1.5

2

2.5

Kraft-C

(SW)

Kraft-C

(SW)

Kraft-C

(SW (P

S/AQ))

Kraft-C

(SW)

Kraft-C

(SW)

Kraft-C

(SW)

Kraft-C

(Euc

alyptu

s)Kraf

t-C (S

W)Sulf

ite

Sulfite

Kraft-C

(SW po

st-D2)

Cu

#

Cu # Tensile Index Tear Index

Bl. Kraft 0.22 20.5 16.3NaBH4 0.03 21.1 16.7

Bl. Kraft 2.30 9.90 12.0NaBH4 0.04 17.2 14.6

The Fate of Fiber Charge During Peroxide Bleaching and Oxygen Delignification

What Contributes to Fiber ChargeUnbleached Kraft Pulps

- Lignin- Polysaccharides

> Uronic Acids> Hexenuronic Acids> Oxidized Reducing Ends

ECF Bleached Pulps

- Polysaccharides> Uronic Acids> Oxidized Reducing Ends> Oxidized Fragments??

- Oxidized Lignin Fragments ??1um

The Fate of Fiber Charge: Peroxide Stage

333435363738394041424344

meq

/kg

pulp

ECF Pulp

E

EOP-70C

EOP-105C

EOP-0.5% MgSO4

EOP-0.1% MnSO4

EOP-0.1% FeSO41% H2O2, 1% NaOH


333435363738394041424344

meq

/kg

pul

ECF Pulp

E

EOP (1% H2O2)

EP (1% H2O2)

EP-(1% H2O2/0.5%MgSO4)EP- (1% H2O2/0.1%FeSO4) EP (2% H2O2)

1% H2O2, 1% NaOH, 70oC


35

35.5

36

36.5

37

37.5

38

38.5

39

39.5

40

meq

/kg

pulp

ECF Pulp (E+P) 40C (E+P) 50C (E+P) 60C (E+P) 70C (E+P) 80C


+ 12%+ 10%46.00H2O2 bleaching

with 0.5% MgSO4

+ 11%+ 10%45.40H2O2 bleaching without MgSO4

37.00Original(fully bleached pulp)

Tear Index Tensile Index

Carboxylic Acid Content (meq./kg O.D. pulp)

Conditions of H2O2Bleaching

1% H2O2, 2% NaOH, 80 oC, 1 h

The Fate of Fiber Charge: O Delignification

0 10 20 30 40 50 6050

60

70

80

90

100

110

120

Car

boxy

lic a

cid,

µm

ol/g

fibe

r

Reaction time, min

1.5% NaOH 2.5% NaOH 3.5% NaOH 640 kPa O2 800 kPa O2 960 kPa O2

85 oC 100 oC 115 oC

Kraft Pulps0 20 40 60 80100

120

140

160

180

200

220 Acid content Kappa number

Time,min

Aci

d, µ

mol

/g,re

sidu

al li

gnin

14

16

18

20

22

24

26

28

30

Kappa num

ber


0 10 20 30 40 50 6085

90

95

100

105

110

Acid

, µm

ol/g

,fibe

r

Time, min

640 kPa 800 kPa 969 kPa

0 10 20 30 40 50 6010

15

20

25

30

Kap

pa n

umbe

r

Time, min

640 kPa 800 kPa 960 kPa

0 10 20 30 40 50 6010

15

20

25

30

Kap

pa n

umbe

r

Time, min

85 0C 100 0C 115 0CHigher O2 Pressure

Better Delignification

Higher TemperatureBetter Delignification

Holocellulose PulpHigher O2 PressureSome Benefit

Holocellulose PulpHigher TemperatureLess Fiber Charge

0 10 20 30 40 50 6085

90

95

100

105

110

Aci

d,µm

ol/g

,fibe

r

Time, min

85 oC 100 oC 115 oC


14 16 18 20 22 24 26 28 3030

40

50

60

70

80

90

100

110

120

130 Bulk pulp Holocellulose Residual lignin

Kappa number

Aci

d, µ

mol

/g, f

iber

or h

oloc

ellu

lose

160

180

200

220

240

260

280

300

320

340

360

380

400

Acid, µm

ol/g, residual lignin

Tensile strength

02

46

810

12

34.82 38.64 55.40Acid groups content in holocellulose,mmol/g

Tens

ile in

dex,

N.m

/g

1. 30 – 50% Delignification

2. Holocellulose

OCH2OH

OROH

OR

OH

OCH2OH

OROH

OR

O

OCH2OH

RO

OR

O-OH

OCH2OH

OR

OOH

OCH2OH

OR

OO

- RO-

OCH2OH

OR

HO COOH

O2/HO-


Kraft SW pulp

OD pulp

Screened a Series of Carboxylic Acid Generating Catalysts:

• Compatible with O-Chemistry• Maintained or improved O-Delignification• No negative effect of cellulose D.P.

OO

O

OH

HOOH

Cellulose

Cellulose

Oxidant

OO

O

OH

HOOH

Cellulose

Cellulose

O


Selective Oxidation of Polysaccharides

Catalyst: Ruthenium pyrochlore oxide (Bi2RuxO7-x)

Reported by Arts et al to be good for monosaccharides only!Journal of Carbohydrate Chemistry 15 (1996) 317-29.

OHO

HO

OH

OHMeO

OHO

H

OH

HOMe

OO

OHO

-O

OH

O-OMe

OO

O

-O

OO OH

OMe

O-

H

OO-

OxidantFast

OxidantSlow

Oxidant


18.715.40.39

18.815.40.18-15.50.10

19.215.50

Viscosity/mPa.sKappa #Catalyst %

Oxygen Delignified Pulp Properties

10% csc, 2.5% NaOH, 800 kPa O2,100 oC

0.0 0.1 0.2 0.3 0.420

30

40

50

60

70

80

Car

boxy

lic a

cid,

µm

ol/g

,Hol

oPul

p

Catalyst, %

O-Catalyst forFiber Charge Development!


18.35

21.42

16

17

18

19

20

21

22

Tensile index(N.m/g)

44.82 61.79Carboxylic acid, µmol/g Holopulp

0.0 0.1 0.2 0.3 0.4 0.520

30

40

50

60

70

80

Car

boxy

lic a

cid,

µm

ol/g

,Hol

oPul

p

Catalyst, %

1. 0 – .18% Catalyst/O

2. Holocellulose


44.8 67.02 80.0400000000000160

65

70

75

80

85 Tensile strength Stretch

Carboxylic acid, µmol/g HoloPulp

Tens

ile in

dex,

mN

/g

2

3

4

5

Stre

tch,

%

Impact of Fiber Charge on Physical Properties

Holocellulose PFI Refined 600 CSFImproved Charge – Improved Tensile Index


44.8 67.02 80.04

6

7

8

9

10

11

12Tensile stiffnessUltrasonic in Plane specific stiffness:longitudial Ultrasonic in Plane specific stiffness:shear

Carboxylic acid, µmol/g HoloPulp

Stif

fnes

s,kN

/mm

2 or k

m2 /s

ec2

3.0

3.5

4.0

4.5

5.0

Shea

r,km

2 /sec

2

Impact of Fiber Charge on Physical Properties

Holocellulose PFI Refined 600 CSFImproved Charge – Improved Stiffness


0.00

20.00

40.00

60.00

80.00

100.00

120.00

140.00

O*

O*D0

O*D0(E

O)O*D

0(EO)D

1O*D

0(EO)D

1D2

O*D0(E

O)DP

Car

boxy

lic a

cid,

µm

ol/g

fibe

r

k.f.=0.18

k.f.=0.22

k.f.=0.26

2% Catalyst in O-stage

12%+ 14%42.2O*D0(EOP)D1

35.1OD0(EOP)D1

µmol/g fiber

Tensile Stiffness

TensileIndexCarboxylic acid

Innovative Cellulosic Fiber-Design:Dielectric Breakdown Discharge

Research Objective: Understand the fundamental DBD interactionswith pulp fibers to improve bonding

Experimental Parameters Examined:• Use of cold plasma to:

• Improve wet/dry strength of TMP/Kraft• Developing New Coatings Technologies• Sheet Chemistry and Barrier Properties

Electrodes

Innovative Cellulosic Fiber-Design:Dielectric Breakdown Discharge

AFM: BKP at Various DBD Treatment Levels

BKP Reference Low (0.20 kW) Medium (8.0 kW) High (22.4 kW) 3 µm x µm phase images.

Innovative Cellulosic Fiber-Design:Dielectric Breakdown Discharge - ESCA

282284286288290Binding Energy (eV)

C1: C-C, C-H: C-C, C-C2: C-O-RC3: O-C-O, C=OC4: R-O-C=O

ESCA C(1s)

2.53

3.54

4.55

0 1 2 3 4 5

DBD (kW/m2/min)

O-C

=O(%

Car

bon)

BKP BKP-ext

25

30

35

40

45

0 2 4 6 8 10

DBD (kW/m2/min)

Acids (µeq/g)

Innovative Cellulosic Fiber-Design: DBD - Wet Stiffness/Strength

0.5

0.6

0.7

0.8

0.9

1

0 2 4 6 8 10

DBD (kW/m2/min)

Wet Tensile (Nm/g)

Bleached SW Kraft

0.6

1.1

1.6

2.1

2.6

0 2 4 6 8 10DBD (kW/m2/min)

Wet Tensile (Nm/g)

Extracted TMPUnextracted TMP

0

2

4

6

8

10

0 2 4 6 8 10

DBD (kW/m2/min)

Wet

Stif

fnes

s (N

/mm

)

SW TMP

Innovative Cellulosic Fiber-Design: DBD - Wet Strength

0

1

2

3

4

0 2 4 6 8 10 12 14

Dose (kW/m²/min)

TI (N

*m/g

)

5.000000006 484 719 1022 1523 4667

Wetting time (in)

121 g/m2 handsheetsSW kraft linerboard

Innovative Cellulosic Fiber-Design: BioGrafting SW Linerboard Fibers

LaccaseEnzymatic Grafting

Phenolic AdditivesDyesCharged structures

NewProperties

OCH3

O

80

85

90

95

100

105

110

ControlVanillic

Syringic4-HBA

ControlLaccase

Kappa #

0.080.1

0.120.140.160.18

0.20.220.24

ControlVanillicSyringic4-HBA

ControlLaccase

Carboxylic Acids (meq/g)

42

43

44

45

46

47

48

49

Con

tact

Ang

le (d

egre

es)

Con Lac GA LGA

20

25

30

35

40

45

Tens

ile In

dex

(N.m

/g)

Con Lac GA LGA

Tensile Improvement

COOH

OH

OH OH

Future Opportunities• Enzymatic control of fiber/sheet properties• Functional paper• Printing

1.51.71.92.12.32.52.72.93.1

kPa.

m2/

g

Con Lac HbaLac

+Hba

Burst ImprovementsCO2H

OH

Innovative Cellulosic Fiber-Design: BioGrafting SW Linerboard Fibers

A Few Good Fibers

Concluding Remarks

A Few Good Fibers: Conclusions• A modern pulp mill has little, if any, control over fiber

charge or oxycellulose content

• Surface charge is preferred but increases in bulk are also beneficial with respect to strength properties

• Improvements in fiber charge are possible via current bleaching protocols

• Surface treatments, biografting, absorption of charged polymers are potentially viable approaches

• More innovative research is needed!

AcknowledgmentsDavid Barzyk, Derek Page

Richard Chandra

NSF, USDA, DOEIPST@GT Research Consortium/Fellowship

Fundamentals of Fiber Modification Chemistry

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