EFFECTS OF FREEZE DRYING ON PAPER

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EFFECTS OF FREEZE DRYINGON PAPER
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INTRODUCTION

• OBJECTIVES
• MATERIALS USED
• EXPERIMENTAL SETUP
• TREATMENT OF SAMPLES
• TEST METHODS
• RESULTS AND DISCUSSION
• CONCLUSION

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INTRODUCTION
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INTRODUCTION

• to investigate how freeze drying effects paper
  characteristics critical to preservation of
  archive and library materials
• to determine how freeze drying might effect the
  mechanical strength and ageing stability of paper

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INTRODUCTION
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MATERIALS USED
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MATERIALS USED
Groundwood paper / Paper 1
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MATERIALS USED
Cotton paper / Paper 2
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MATERIALS USED
Coated paper / Paper 3
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EXPERIMENTAL SETUP
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EXPERIMENTAL SETUP
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TREATMENT OF SAMPLES
Soaking in demineralized water
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TREATMENT OF SAMPLES
Freeze drying by cold chamber wall
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TREATMENT OF SAMPLES
Freeze drying by warm chamber wall
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TREATMENT OF SAMPLES
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TREATMENT OF SAMPLES

• Accelerated ageing

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TREATMENT OF SAMPLES

• Accelerated ageing
• 12 days (288 hours)
• 90 ºC
• 50 RH

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TEST METHODS

• Moisture content SCAN P 463
• Alkali reserve ISO 10716
• Folding endurance SCAN P 1777
• Tearing resistance SCAN P 1173
• Zero span tensile Cowan/TAPPI 231 (dry and wet
  determination)

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RESULTS DISCUSSION

• freeze drying particulary influences moisture
  content, folding endurance and tearing resistance
• freeze drying and accelerated ageing influence
  moisture content, folding endurance and tearing
  resistance in the samples, but differently from
  one paperquality to another
• the effect on alkali reserve and zero span
  tensile strength is relatively small

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RESULTS DISCUSSION
Folding enduranceGroundwood paper / Paper 1
Log 10 / GM
Reference
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RESULTS DISCUSSION
Zero span dryGroundwood paper / Paper 1
Nm/g / GM
Reference
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RESULTS DISCUSSION
Tearing resistanceGroundwood paper / Paper 1
mNm2/g / GM
Reference
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RESULTS DISCUSSION
Moisture contentGroundwood paper / Paper 1
Moisture content
Reference
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RESULTS DISCUSSION
Folding enduranceCotton paper / Paper 2
Log 10 / GM
Reference
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RESULTS DISCUSSION
Tearing resistanceCotton paper / Paper 2
mNm2/g / GM
Reference
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RESULTS DISCUSSION
Folding enduranceCoated paper / Paper 3
Log 10 / GM
Reference
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RESULTS DISCUSSION
Tearing resistanceCoated paper / Paper 3
mNm2/g / GM
Reference
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RESULTS DISCUSSION
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RESULTS DISCUSSION
Retention of folding endurance andtearing
resistance after accelerated ageing
Retention
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RESULTS DISCUSSION
Retention of zero span tensilestrength after
accelerated ageing
Retention
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CONCLUSION
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CONCLUSION

• freeze drying particularly influences moisture
  content, folding endurance and tearing resistance
• freeze drying and accelerated ageing effect
  moisture content, folding endurance and tearing
  resistance differently in various paperqualities
• freeze drying of groundwood paper and alum-rosin
  sized paper with a high amount of fillers reduces
  the mechanical strength

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CONCLUSION

• freeze drying of cotton paper with a high content
  of calcium carbonate has a relatively limited
  effect on mechanical strength and ageing
  stability
• freeze drying of coated paper particularly
  reduces folding endurance

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CONCLUSION
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ACKNOWLEDGEMENT

• Jonas Palm, The Royal Library
• Grethe Jørgensen, The School of Conservation
• Jørn Bredal-Jørgensen, The School of Conservation
• Anette Linde, Swedish Pulp and Paper Research
  Inst.
• Poul Jensen, The National Museum
• Julie Fryd Johansen, The Royal Library
• Stora Papyrus, Grycksbo

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Thank you for yourattention
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