final-ppt

1

Performance Enhanced Pulp by Cellulose NanomaterialsEugenia Chan, Jeremy KimMentor: Dr. Yao

http://www.mseco.com/wp-content/uploads/2014/07/paper_large.jpg

2

Purpose

• Collaboration with Ecosynthetix • Renewable chemicals company with a focus on

alternatives to petroleum-based products

• Goal• Enhance paper’s dry and wet tensile strength

using cellulose nanomaterials (CNF) and starch nanoparticles (Ecosphere) on the order of 20% greater than unmodified paper products

3

Materials Used in this Project• Pulp

• Brazil• BCTMP

• CNF• Hardwood• Softwood

• Starch Nanoparticles• Ecosphere 2777

4

Pulp and Paper Industry• Origin of papermaking dates back

to ~100 AD China• Rags, hemp and grass were beat

against stone mortars to break down its fibres

• Pulping wood was developed ~1800s• More abundant fibre source • Still used in modern pulp & paper

manufacturing

• In modern times, papermaking is a large integration operation including:• Foresting• Lumbermilling• Pulp & Paper Manufacturing• Conversion

Teschke K. (2011). Paper and Pulp Industry: General Profile. Encyclopedia or Occupational Health and Safety. Chapter 72. Retrieved from http://www.iloencyclopaedia.org/part-x-96841/paper-and-pulp-industry

5

Pulp• Main component is cellulose

• Strong H-bonds that holds the fibres together

• 600 to 1500 repeating alternating D-glucose molecules

• Modified using additives

• Different types of woods have different proportions of components• Our project involves Softwoods

and Hardwoods pulp

Keefe A. & Teschke K. (2011). Paper and Pulp Industry: Fibre Sources for Pulp and Paper. Encyclopedia or Occupational Health and Safety. Chapter 72. Retrieved from http://www.iloencyclopaedia.org/part-x-96841/paper-and-pulp-industry

Royal Society of Chemistry (2013). Paper Conservation Cellulose Acid Hydrolysis. Education in Chemistry Magazine. Retrieved from: http://www.rsc.org/education/eic/issues/2013March/paper-conservation-cellulose-acid-hydrolysis.asp

Table 1. Chemical Compositions of Pulp and its Sources (Keefe & Teschke (2011)

6

Pulping• Process of exposing fibrous

structures of pulp by rupturing bonds within wood structure• Mechanical • Chemical

• Pulping process was already done and pulp was provided by:• Suzano Papel e Celulose

(Brazil)• West Fraser (BCTMP)

Anderson J., Anastrakianakis G. & Keefe A. (2011). Paper and Pulp Industry: Pulping. Encyclopedia or Occupational Health and Safety. Chapter 72. Retrieved from http://www.iloencyclopaedia.org/part-x-96841/paper-and-pulp-industry

7

Properties of Pulp

Brazil

• 0.0176 mM/g of COOH content• Hardwood from Eucalyptus trees

• Shorter fiber length, lower pulp strength

BCTMP

• 0.024 mM/g of COOH content• Zeta potential: -25.3 mV• Softwood

• Longer fiber length

8

Bleached Chemical Thermo-Mechanical Pulp (BCTMP)

• Softwood• Used to manufacture coated boards,

printing/writing paper and paper towel/napkin grades

• From Lodgepole Pine and White Spruce trees

• Advantages• Produce 2x the yield of pulp

compared to other chemical pulps (85% vs. 42%)

• More environmentally friendly → chlorine-free bleaching

CANNELL, E. (2000, May 1). PULP & PAPER MAGAZINE:The Future of BCTMP. Retrieved from http://legacy.risiinfo.com/magazines/May/2000/PP/pulp-paper/magazine/may/2000/The-Future-of-BCTMP.html

Softwood BCTMP provided by West Fraser

9

Optical Microscopy Images of BCTMP

• Long fibers that are a couple of mm in length• Small amount of fibrillated fibers

10

What is CNF?• Referred to as Cellulose Nanofibers (CNF) or Microfibrillated Cellulose

(MFC)• Size: 20-50 nm• Nanocomponent of cellulose, acquired by mechanical methods

(shearing) using high pressure homogenizer• Contains amorphous and crystalline regions• Our project involved 2 different types of CNF samples:

• CNF from Hardwood (CNF-H)• CNF from Softwood (CNF-S)

Nasirpour A., Fathi M. & Rezzei A. (2015). Application of Cellulosic Nanofibers in Food Science Using Electrospinning and Its Potential Risk. Comprehensive Review in Food Science and Food Safety. Vol 14-3. Retrieved from: http://onlinelibrary.wiley.com/doi/10.1111/1541-4337.12128/pdf

11

Properties of CNF• Lightweight material• Renewable resource and biodegradable• High surface area and high tensile strength (138 GPa)

compared to pulp fiber (2 GPa)• Hydroxyl groups on the surface allow for various

chemical modifications • Negatively charged

CNC

5-20 nmMircofibrillated

Cellulose (CNF/MFC)20-50 nm

Elementary fibrils 5 nm

Chemical structure

Amorphous region

Crystalline region Pulp Fibers

12

CNF-Hardwood• 0.048 mM/g of COOH content• Zeta Potential: -36.1 mV

CNF-H

13

CNF-Softwood• 0.064 Mm/g of COOH content• Zeta Potential: -22.5 mV

CNF-S

14

Optical Microscopy Images of CNF-H

• Few long fibers that are mm in length• Most fibers are hundred microns in length

15

Optical Microscopy Images of CNF-S

• Some long fibers that are mm in length• Considerable amount of fibrillated fibers that are hundred microns in

length

16

Starch Nanospheres• Starch

• natural, renewable, and biodegradable polymer

• consists of linear amylose (~75%) and branched amylopectin (~25%)

• contains both amorphous and crystalline regions

Corre, D. L., Bras, J., & Dufresne, A. (2010). Starch Nanoparticles: A Review. Biomacromolecules, 11(5), 1139-1153. doi:10.1021/bm901428y

17

Ecosphere 2777• Starch particles cationically modified

by quaternary amine• Zeta potential: 16.9 mV• Size measured by DLS: Rh = 92.5 nm

Ecosphere 2777

18

Traditionally Used Wet Strength Agents• Urea-Formaldehyde (UF) resin

• network created by self-crosslinking• not environmental friendly

• Polyamide Epichlorohydrin (PAE) • formation of covalent bonds between PAE and

cellulose fibers• negatively impacts environment due to organic

chloride → limited use in paper mills now

Espy, H. H. (1995). The mechanism of wet-strength development in paper: a review. Tappi Journal, 78(4), 90-100.

19

Advantages of CNF and Cationic Ecosphere

• High surface area of CNF and Ecospheres → increases the number of bonds between the pulp fibers

• CNF can be modified to have positive charges on the surface

• Negatively charged pulp will have electrostatic interaction with cationic Ecospheres and modified CNF

20

Forming Handsheets for Physical Testing• TAPPI T-205 “Forming Handsheets for Physical

Tests of Pulp” • Disintegration (mixing and dispersion of pulp fibres)• Sheetmaking (filtration of pulp)• Couching (Blotting and rolling of fresh sheet)• Pressing• Drying • Testing of sheets (Tensile strength)

• Followed this stepwise procedure, making appropriate alterations• Included procedure in adding additives to pulp

21

Disintegration• Process of breaking and dispersing pulp

fibres into smaller components• Guidelines from Pulp Company:

• Dilute to 4-8 wt% (we used 4%), mix for minimum of 20 minutes

• Even after several hours, still chunky consistency• Sheets were not homogenous

• Guidelines from TAPPI T 205:• Dilute to 1.2 wt% (we used 1.5%), mix at high rpm• Dilute to 0.3 wt%, stir at high rpm until properly

mixed• Starting at a lower consistency produced more

homogenous sheets• Final procedure: Mix at 1.5 wt% for 1 hour, dilute

to 0.3 wt% and mix for 30 mins

Disintegration of pulp

22

Sheetmaking

• Glass Filtration• screening trial of sheetmaking• Pros:

• Setup was stable allowed for more homogenous filtration

• Cons: • Sheets were too small could not

be properly tested

Glass filtration setup

23

Sheetmaking

• Buchner Funnel• Pros: Larger diameter, allows for

larger sheets• Cons: Membrane was not

completely flat, resulted in non-homogenous areas

• Different types of filter membrane used led to sheet sticking to it

• Cloth + metal mesh membrane was made to avoid sticking

Buchner funnel setup

Cloth + metal mesh

24

Sheetmaking• Filtration

• Set-up designed and made by Dr. Yao

• Wire mesh (size: 200 mesh) used instead of cloth or filter paper to eliminate problem with sheet sticking

• Solution diluted by adding additional 1250 mL of water, mixed and allowed to settle before applying vacuum• More homogenous sheets

Current filtration set-up

Wire mesh

25

Couching/Pressing• Filter papers were used as

blotters, rolled to soak up excess water on sheets

• Preliminary pressing step • More homogenous sheets,

prevented wrinkling and greater tensile strength

• Implemented a standard pressing procedure • Hydraulic press at 50 psi for 5

mins, then again for 2 mins after replacing blotters Hydraulic press

26

Modifying Pulp• Created modified pulp solution

by mixing pulp and additive• Initial attempt:

• Combined 0.3 wt% pulp and 0.3 wt% additive together and mixed for 10 mins

• Sheets were not homogenous due to formation of aggregates

• Decreased additive from 0.3 wt% to 0.1 wt%, added dropwise and mixed for 30 mins• Allowed for better dispersion of

additive within pulp solution• More homogenous sheets

Additive

Modified Pulp Solution

27

Drying

• Hotplate method• Sheet was placed

between glass plates and heated on hotplate at 90oC with weight placed on top for 5 min, then air dried• Heat was not

distributed evenly onto sheet, bottom was heated but top was not

• Very inefficient when drying multiple sheets

Hotplate method of drying

28

Drying• Current method• Multiple handsheets are placed between glass

plates and dried overnight in oven at 70o C• Weights placed on top of plates to prevent

wrinkling

Oven drying method

29

Testing• Tensile Strength (TS): Maximum applied tensile

force a specimen can withstand before rupturing• Force (NZ) per unit width (m), NZ/m• Force is applied through the z-axis by UMT machine,

width of strip is 0.015m• Factors affecting: fibre strength, fibre length and

bonding• TS = FZ/(width of strip)

• Tensile Index (TI): Relates the strength of the specimen with the amount being loaded• Provides relative strength of sheet• Tensile strength (NZ/m) divided by grammage (g/m2)• TI = TS/(mass of strip/Area of strip)

Muchorski D. (2006). Tensile properties of paper and paperboard. TAPPI (2), T 494. Retrieved from: http://www.tappi.org/content/sarg/t494.pdf

30

Testing

• 5 15mm x 60mm strips are cut and weighed from each handsheet and tested

• Universal Testing Machine is used to apply a stretching force to the z-axis• Machine usage provided by Dr. Boxin

Zhao• 5 dry tests and 5 wet tests

• Wet test: 30 µL is dropped onto middle of strip prior to test

• Water affects tensile strength by affecting the swelling behaviour of fibres

Strips cut from handsheet

Testing using UTM

31

Testing • Tensile strength of different types

of sheets are compared to a 100% pulp sheet control group

• Literature value of raw pulp is given in table

• Preliminary testing of pulp done with a 100% BCTMP sample• Dry tensile index of 25.97 Nm/g• Confirms that data is agreeable and

reproducible

Hsieh J. & Yoo S. (2010). Enzyme-Assisted Preparation of Fibrillated Cellulose Fibers and Its Effect on Physical and Mechanical Properties of Paper Sheet Composites. Ind Eng Chem Res. Vol 49 Issue 5. Retrieved from: http://pubs.acs.org/doi/abs/10.1021/ie901621n

http://pubs.acs.org/doi/abs/10.1021/ie901621n

http://pubs.acs.org/doi/abs/10.1021/ie901621n

32

Current Additives to Pulp• CNF-GTMAC

• CNF-g-pAPTAC and CNF + pAPTAC

• Ecosphere 2777

33

CNF-GTMAC• CNF is modified with cationic Glycidyltrimethylammonium chloride (GTMAC) • Carried out in an aqueous solution instead of using an organic solvent such as DMSO • safer, easier to scale up for a large scale

process

34

CNF-GTMAC• Procedure: Dissolved CNF in NaOH solution and

stirred the mixture at 50°C for 4 hours, dropwise added GTMAC over 1 hour and stirred the mixture at 60°C

• Zeta potential: 39.7 mV, higher than CNF (-26.1 mV).

• Positively charged so it will better adhere to negatively charged pulp

• After 1 week of storage, CNF-GTMAC is more stable than CNF

CNF-GTMAC (left) and unmodified CNF (right)

35

Preliminary Tensile Index Results using CNF-GTMAC

• at both 5% and 10%, the addition of CNF-GTMAC to pulp increased the dry and wet tensile index over 20%

Samples

Tensile index Nm/g % increase

Dry Wet Dry Wet100% pulp 21.16 2.12

CNF-GTMAC

5% 36.87 2.72 54.20 28.3010% 38.04 3.09 79.80 45.80

36

Polymerization of (3-acrylamidopropyl)triethylammonium (APTAC)

• Free radical polymerization using ammonium persulfate (APS) as initiator

• Procedure: Mixed CNF with initiator APS and bubbled the mixture with N2 gas for 1 hr, added APTAC in dropwise fashion, then stirred the mixture at 70°C overnight.

CNF

APTAC

37

pAPTAC

• In 125 mg of CNF-g-pAPTAC, 0.8 wt% is the polymer• 0.038 mM/g

• Zeta potential: • CNF-g-pAPTAC (grafted): –20.8 mV• CNF-pAPTAC (mixed) (1:0.01): –20.8 mV• no difference in zeta potential when

pAPTAC is grafted or mixed with CNF

38

Preliminary Tensile Index Results using pAPTAC

• only the samples with 10% CNF-g-pAPTAC added to the pulp showed a 20% increase for both the dry and wet tensile index

Samples

Tensile index Nm/g % increase


CNF-g-pAPTAC

5% 35.58 2.13 49.80 0.5010% 43.55 2.89 105.80 36.30

CNF:pAPTAC (1:0.5)

5% 23.63 1.52 6.70 -28.3010% 29.85 2.27 41.10 7.10

39

Ecosphere 2777

• both 5% and 10% Ecosphere 2777 added to the pulp showed much greater than 20% increase for both the dry and wet tensile index

Samples

Tensile index Nm/g

% increase


Ecosphere 2777

5% 41.23 3.74 94.80 76.4010% 38.06 5.15 79.90 142.90

40

Ecosphere 2777:CNF-S

• zeta potential of the mixture of Ecosphere 2777 and CNF-S increased when increasing the amount of 2777

• zeta potential stayed almost unchanged after the ratio exceeded 0.1

Eco2777:CNF-SZeta potential (mV)

0 -22.50.1 15.2

0.25 14.90.5 16.0

1 16.72 16.93 20.25 16.6

41

TEM Image of Ecosphere 2777:CNF-S (1:1)

• dark coloured circles embedded on fibers show that ecosphere particles have bonded to CNF-S

42

Tensile Index Results of Ecosphere 2777:CNF-S (1:1)

• when more than 3% of Ecosphere 2777 mixed with CNF-S at 1:1 ratio is added to the pulp, the dry and wet tensile index increased by more than 20%

• however, standard deviation is high, more homogenous sheets need to be made

Samples

Tensile index Nm/g % increase SD

Dry Wet Dry Wet Dry Wet100% pulp 25.17 2.81 1.87 0.56


(1:1)

1% 30.18 3.20 19.93 13.97 5.14 0.973% 34.05 3.39 35.30 20.62 2.28 1.245% 43.16 4.03 71.49 43.44 6.06 1.228% 41.26 3.87 63.96 37.82 5.13 0.56

43

Tensile Index Results of Ecosphere 2777:CNF-S (1:2)

• when more than 1% of Ecosphere 2777 mixed with CNF-S at 1:2 ratio is added to the pulp, the dry and wet tensile index increased more than 20%

• however, the trend is not consistent, perhaps due to formation of large aggregates

Samples



Ecosphere 2777:CNF-

S (1:2)

1% 29.34 2.82 21.24 23.38 5.61 0.523% 32.53 2.84 34.43 24.25 6.95 1.175% 51.21 3.42 111.60 49.50 7.38 0.73

8% 39.81 3.14 64.50 37.4712.8

3 0.24

44

Ecosphere 2777:CNF-H

• zeta potential of the mixture of Ecosphere 2777 and CNF-H increased when increasing the amount of 2777

• zeta potential stayed almost unchanged after the ratio exceeded 1

Eco2777:CNF-H

Zeta potential (mV)

0 -36.10.1 10.1

0.25 10.50.5 12.4

1 16.72 19.13 18.85 19.4

45

TEM Image of Ecosphere 2777:CNF-H (1:1)

• dark coloured circles embedded on fibers show that Ecosphere particles have bonded to CNF-H

46

Tensile Index Results of Ecosphere 2777:CNF-H (1:1)

• when more than 1% of Ecosphere 2777 mixed with CNF-H at 1:1 ratio is added to the pulp, the dry and wet tensile index increased more than 20%

• however, standard deviation is high, more homogenous sheets need to be made

Samples




(1:1)

1% 30.50 3.50 21.17 24.66 3.42 0.303% 41.36 4.14 64.34 47.19 5.69 0.535% 37.59 4.34 49.36 54.40 3.37 0.498% 39.62 4.48 57.42 59.55 3.70 0.84

47

Tensile Index Results of Ecosphere 2777:CNF-H (1:2)

• when more than 3% of Ecosphere 2777 mixed with CNF-H at 1:2 ratio is added to the pulp, the dry and wet tensile index increased more than 20%

• trend is consistent, however standard deviation is high, more homogenous sheets need to be made

Samples



Ecosphere 2777:CNF-

H (1:2)

1%25.15 2.70 3.92 18.09 2.86 0.373%34.42 2.79 42.22 22.00 6.87 0.79

5%38.59 2.96 59.47 29.46 4.24 0.318%41.34 4.24 70.84 85.4413.15 0.43

48

Comparison of Ecosphere 2777:CNF (1:1 and 1:2)

• Comparing the % increase in tensile index of Ecosphere 2777:CNF at ratios of 1:1 and 1:2, adding more CNF did not increase the tensile index very much and in some cases had an even lower tensile index

Samples% increase

Samples% increase

Dry Wet Dry Wet


(1:1)

1% 19.93 13.97


(1:2)

1% 21.24 23.383% 35.30 20.62 3% 34.43 24.255% 71.49 43.44 5% 111.60 49.508% 63.96 37.82 8% 64.50 37.47


(1:1)

1% 21.17 24.66


(1:2)

1% 3.92 18.093% 64.34 47.19 3% 42.22 22.005% 49.36 54.40 5% 59.47 29.468% 57.42 59.55 8% 70.84 85.44

49

Ecosphere 2777:CNC

• zeta potential of the mixture of Ecosphere 2777 and CNC increased when increasing the amount of 2777

• zeta potential stayed almost unchanged after the ratio exceeded 2

Eco2777:CNC

Zeta potential (mV)

0 -41.450.1 -20.4

0.25 -18.30.5 -13.3

1 12.552 15.453 16.855 15.85

50

TEM Image of Ecosphere 2777:CNC (1:2)

• dark coloured circles are Ecosphere particles, light coloured rods are CNC

• appears that Ecosphere particles mixed well with CNC

51

Tensile Index Results of Ecosphere 2777:CNC (2:1)

• only the samples with 8% Ecosphere 2777:CNC at 2:1 ratio added to the pulp showed a 20% increase for both the dry and wet tensile index

• wet tensile index even decreased due to CNC’s ability to disperse well in water when the paper absorbed water, CNC lost it’s adhesion capability

SamplesTensile index

Nm/g % increase SDDry Wet Dry Wet Dry Wet

100% pulp 20.37 3.06 1.63 0.07Ecospher

e 2777:CNC (2:1)

1% 23.96 2.65 17.62%-13.59% 4.68 0.283% 24.07 3.01 18.16% -1.74% 4.38 0.495% 38.1 2.93 87.04% -4.35% 7.38 0.798% 30.95 3.95 51.94% 29.01% 1.24 0.34

52

Conclusion• From the results gathered so far

• Ecosphere 2777 mixed with CNF-H and CNF-S and added to pulp reach the goal of increasing the dry and wet tensile index by 20%

• CNF-GTMAC added to pulp also shows promising preliminary results and can further be tested as necessary

• CNC will not be used again since results did not reach goal and also more expensive compared to CNF

53

Conclusion• Next steps

• Handsheet making process can be further improved in order to make more homogenous sheets to decrease standard deviation and produce more reliable results

• Make and test sheets:• Ecosphere 2777:CNF-H/S at 2:1 ratio• CNF-H and CNF-S• Ecosphere 2777 mixed with CNF-S dry product

provided by company

54

THANKS FOR LISTENING

http://www.mseco.com/wp-content/uploads/2014/07/paper_large.jpg

Documents

final-ppt