LbL Nanocoating for Fiber Recycling Improved Paper Recycling through - - PowerPoint PPT Presentation

LbL Nanocoating for Fiber Recycling

Improved Paper Recycling through Fiber Polycation/Polyanion Multilayer Nanocoating

• J. Y. Zhu1, M. Fleischmann1, Z. Zheng2, E. Lvov3, G. Grozdits3, 4, J. Chapman5

and Y. Lvov2, 3

1 USDA Forest Service, Forest Products Laboratory, Madison, WI, 2 Institute of

Micromanufacturing at Louisiana Tech University, Ruston, LA, 3 Nano Pulp and Paper LLC, Ruston, LA, 4 School of Forestry at Louisiana Tech University, Ruston, LA, 5 Smurfit-Stone Paper Corp. Hodge, LA Tappi - 8th Research Forum on Recycling Niagara Falls, ON, Canada September 23-26, 2007

Niagara Falls, ON, Sept. 23-26, 2007

Paper Recycling is driven by economic incentives and societal pressures It requires modified/new fiber preparations and paper making Recycling in part requires used fiber rejuvenation But it allows creation and operation of small and specialty mills close to resources and market,

Niagara Falls, ON, Sept. 23-26, 2007

Damaged Fibers (green positive), virgin fiber (red negative), they electrostatically attract each other

In this paper we report on the rejuvenation of fibers from recycled paper by Layer-by-Layer Self Assemblies of polyelectrolytes onto fibers to create enhanced electrostatic bonding potentials

Niagara Falls, ON, Sept. 23-26, 2007

Micro-Emulsion Technologies

• 10-6 m droplets
• spot-welding of fiber

Layer-by-Layer Nanocoating

• 10-9 m thick continuous coatings
• fiber surface contact bonding

Emulsified electrolytes Short fibers Whole fibers

Basics of Layer-by-Layer Assembly by Alternate Adsorption of Oppositely Charged Linear Polyions and Nanoparticles

The LbL-assembly regimes for more than 50 compounds were established at IfM (using the “dipping automate” equipment).

• Y. Lvov, K. Ariga, T. Kunitake, J. Am. Chem. Soc., 1995, v.117, 6117-6122 "Assembly of

multicomponent protein films by means of electrostatic layer-by-layer adsorption"

Development of Nano-LbL-selfassemblies

1992-1999 G.Decher, H.Moehwald, Y.Lvov,

M.Rubner, J.Fendler, J.Schlenoff, P.Hammond, N.Kotov, T.Kunitake, F.Caruso, G.Sukhorukov

• G. Decher Science, 1997, v.227, 1232 “Fuzzy nanoassemblies: Toward layered multicomposites”

Niagara Falls, ON, Sept. 23-26, 2007

Nano assemblies change cellulose fibers properties

Confocal images Zeta (ξ) potential approximation Presence of nano-layers Fiber surface properties, as well as, shown labeled electrolyte mechanical & physical properties

Niagara Falls, ON, Sept. 23-26, 2007

History and Development of The Louisiana Tech Nano Pulp and Paper Initiative

Established LbL nanocoating feasibility in clean-lab conditions

• 1. Used positive & negative LbL treated unbeaten bleached Kraft

commercial pine pulp

• 2. Used unbeaten bleached Kraft commercial pine pulp with LbL treated

broke and fines in clean lab conditions

• 3. Used machine stock with LbL treated mill broke, LbL treatment in DI

water

• 4. Used machine stock with LbL treated mill broke, LbL treatment in mill

process water This work report on the use of 100 % recycled linerboard pulps, in a limited pilot plant study can, done at USDA-FS-FPL at Madison, WI. To demonstrate how we move from clean lab conditions to practical paper recycling and linerboard production

Niagara Falls, ON, Sept. 23-26, 2007

40 80 120 160 200

Tensile Index N•m/g

1 2 3 4

Orginal pulp Orginal+positive pulp Orginal+negative pulp Positive+negative pulp

Tensile strength (Tappi-T205 standard) of hand sheets made from LbL- treated (with {PAH/PSS}.5 electrolytes) softwood unbeaten commercial

• pulp. LbL nanocoating was done under “clean-lab” conditions. The

commercial pulp was washed and treatments done in DI water.

100 % increase in paper tensile index

• Z. Zheng, J. McDonald, R. Khillan, T. Shutava,, G. Grozdits, Y. Lvov. J.

Nanoscience and Nanotechnology, v.6, 1-9, 2006 Niagara Falls, ON, Sept. 23-26, 2007

2 4 6 8 1 1 2 1 4 1 6 1 % b ro ke n 3 % b ro ke n co n t ro l (u n t re a t e d w h

• l e

f i b e r + u n t re a t e d b ro ke n f i b e r) N e g a t i ve w h

• l e

f i b e r + p

• si t i ve

b ro ke n f i b e r

Tensile strength (Tappi-T205 standard) of hand sheets made from unbeaten softwood commercial pulp with the additions of 10% and 30% LbL-treated (with {PAH/PSS}3.5 electrolytes) short fibers and fines (simulated broke). LbL nanocoating was done in “clean-lab” conditions.

50 % increase in tensile index

Y.M. Lvov, G.A. Grozdits, S. Eadula, Z. Zheng Z. Lu. Northern Pulp & paper Research Journal v. 21, no 5: 552-557, 2006 Niagara Falls, ON, Sept. 23-26, 2007

40 50 60 70 80 90 100 control (0%) 10% 20% 30% 40% Broken Fiber ratio (%) Tensile Index (N•m/g) Control: Handsheets prepared from untreated w hole fibers Others: Handsheets prepared from LbL treated negative w hole fibers mixed w ith LbL treated positive broken fibers

Tensile strength (Tappi 205 Standard) of handsheets made from southern pine virgin machine stock and paper mill broke from Hodge Paper mill, LA. The pulps were washed in DI water, then treated with {PAH/PSS}3.5 electrolytes. Each electrolyte self- assembly was done in “clean lab” conditions (electrolyte in 0.5N NaCl DI water solution

LbL nanocoated papermill stock increased tensile index by 50 to 15 %

Niagara Falls, ON, Sept. 23-26, 2007

Effect of LbL Treatment of Mill Broke on Tensile index

70 75 80 85 90 1 Pulp Compositions - see Legend Tensile Index - N m/g 100% UB 100% UM 30% UB/70% UM 30% TB/70% UM 40% TB/60% UM

Tensile strength (Tappi 205 Standard) of handsheets made from Southern pine virgin machine stock and paper mill broke from Hodge Paper mill,

• LA. The pulps were not washed before treatment and LbL nanocoated

with {PDDA/PSS}3.5. LbL nanocoating was done in mill process waters (“dirty water”) with electrolyte concentration control.

Nanocoating in unwashed pulps in mill process waters “dirty water” increased tensile index by 15 %

UB-untreated broke UM-untreated machine stock TB-treated broke

Niagara Falls, ON, Sept. 23-26, 2007

The objectives: Effect of washing Effect of refining Partial coating

Application OF LBL to 100% OCC

Old corrugated cardboards (OCC) under close to practical paper recycling conditions were recycled with LbL treatment with (PAH/PSS)1.5 electrolyte layers. 6-inch diameter handsheets were made from using 50 % untreated and 50 % LbL treated pulp with one or three self- assembled layers. Pulp and handsheet properties; Canadian standard freeness, sheet density, basis weight, paper thickness (caliper), stiffness, tensile index, bulk, tear index, stiffness index, and modulus, were measured or tested. This work was done at the USDA-FS-Forest Products Laboratory, Madison, WI

Niagara Falls, ON, Sept. 23-26, 2007

10 20 30 40 50 60 70

pulp not coated

Control, 100% unrefined Control, 100% refined 50% refined + 50% refined and coated One layer coating Three layer coating

Tensile index (N-m/g)

Coating applied to 50% of the refined pulp, no washing

Tensile index of handsheets made with refined (negative,) and with refined-LbL nanocoated (positive) recycled linerboard pulps from old container linerboards.

Niagara Falls, ON, Sept. 23-26, 2007

10 20 30 40 50 60 70

pulp not coated

Control, 100% unrefined Control, 100% refined 50% refined + 50% refined and coated One layer coating, no washing One layer coating, washing Three layer coating, no washig Three layer coating, washing

Tensile index (N-m/g)

Coating applied to 50% refined pulp

Effect of pulp washing between and after LbL polyelectrolyte nanocoating on tensile index handsheets made from old container linerbboards.

Niagara Falls, ON, Sept. 23-26, 2007

Effect of LbL on sheet densification

600 620 640 660 680 700 720 30 40 50 60 70 80

Unrefined control, uncoated 50% refined, uncaoted 100% refined, uncoated 50% refined uncoated+50% unrefined coated, washed

• ne layer

three layers 50% refined uncoated+50% refined coated

• ne layer, unwashed
• ne layer, washed

three layers, washed three layers, unwashed

Tensile index (Nm/g) Sheet density (kg/m

3)

Niagara Falls, ON, Sept. 23-26, 2007

Limited Pilot Scale Experiments -Conclusion

• 1. Refining (beating) itself can improve paper

bonding significantly as it is known.

• 2. LbL nanocoating with PAH/PSS

polyelectrolytes of recycled linerdboard pulps also improved paper strength.

• 3. Washing of the nanocoated pulps between

and after polyelectrolyte applications has a negative effect because washing actually removes fines.

• 4. Multiple LbL nanolayering can improve paper

strength, when using 50 : 50 mix of positive and negative surface potential pulps.

Are the LbL molecular layers really separated in the LbL multilayer? Or we creating a composite layer with new “composite” properties?

Niagara Falls, ON, Sept. 23-26, 2007

PSS Absortion

0.05 0.1 0.15 0.2 0.25 0.3 0.35 1st PSS 2nd PSS 3rd PSS

Treatment Sequence PSS Concentration Chang

• mg/ml

Mashine Stock Recycled Stock

Recycled fiber surfaces adsorbed different, smaller amounts of PSS electrolyte, than virgin pulp

Niagara Falls, ON, Sept. 23-26, 2007

THANK YOU Louisiana Tech Nano Pulp and Paper Initiative in Cooperation with USDA-FS-Forest Products Laboratory, Madison, WI

Niagara Falls, ON, Sept. 23-26, 2007