Properties of hemp fibre polymer composites -An optimisation of ...

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Preface This thesis is submitted as a partial fulfilment of the requirements for the Danish Ph.D. degree. The study was carried out from September 2001 to April 2005 at the Danish centre for Forest, Landscape and Planning, The Royal Veterinary and Agricultural University (KVL). Part of the experimental research has been carried out at Materials Research Department (AFM), Risø National Laboratory, at the Biosystems Department (BIO), Risø National Laboratory, at the Wood Ultra Structure Research Centre, Swedish University of Agricultural Sciences (SLU) and at Department of Chemistry, Technical University of Denmark. It was defended 23 rd September 2005. During the three years of work that has resulted in this thesis, many people have contributed in one way or another. I am very grateful of all of you; but there are some who deserve special thanks. First of all I will thank Dr. Anne Belinda Thomsen for introducing me to the project and for the 8 month I was involved in bioethanol research. I wish to acknowledge all my supervisors for their encouraging support and inspiration and for giving me the freedom to choose the subjects of my interest. Especially, I am thankful for the many fruitful discussions of the applied experimental procedures and the obtained results. Furthermore I express my gratitude to Mrs. Ann-Sofie Hansen, Mr. Henning K. Frederiksen, Mr. Tomas Fernqvist, Mrs. Ingelis Larsen, Dr. Bo Madsen, Engineer Tom L. Andersen, Lecturer Kenny Ståhl and Dr. Geoffrey Daniel. This work was part of the project “High performance hemp fibres and improved fibre networks for composites” supported by the Danish Research Agency of the Ministry of Science. Their support is gratefully acknowledged. This work was supervised by: Professor Claus Felby (SL-KVL) Main supervisor Senior Scientist Hans Lilholt (AFM) Co-supervisor Senior Scientist Anne Belinda Thomsen (BIO) Co-supervisor Risø National Laboratory: 5 th April-2006 6 Risø-PhD-11
1 Resumé Karakterisering af hampefibre blev udført med fibre fremstillet ved skånsomme metoder for at få en indikation af hvor stærke fibre der kan produceres fra hampeplanten. Sammenligning blev lavet med hampegarn produceret under traditionelle betingelser, hvor skader ikke kan undgås. Den skånsomme defibrering af hampestænglerne blev udført ved nedbrydning af den pektin- og ligninholdige midtlamel omkring fibrene ved kultivering af den muterede svamp Phlebia radiata Cel 26. De fremstillede fibre havde et celluloseindhold på 78 %, hvilket også kan opnås ved enzymbehandling med pektinnedbrydende enzymer efterfulgt af steam explosion behandling. S2-laget i fibrenes cellevæg bestod af 1-4 lag med højt celluloseindhold og lavt ligninindhold. Disse lag bestod endvidere af ca. 100 nm tykke lameller. Mikrofibrilvinklen var 0-10° i hovedparten af S2-laget og 70-90° i S1-laget. Siden mikrofibrilorienteringen næsten var parallel med fiberretningen havde fibrene høj stivhed der kunne blive 94 GPa efter defibreringen. De defibrerede hampefibre var dermed stivere end hampegarn (60 GPa), hvilket kan skyldes snoningsvinklen der introduceres under spindingsprocessen. Hampefibrenes stivhed var også lineært voksende som funktion af celluloseindholdet og cellulosekrystalliniteten og aftagende som funktion af snoningsvinklen eller mikrofibrilvinklen. Krystallinsk cellulose havde en estimeret stivhed på 125 GPa. Defibreringen med P. radiata Cel 26 resulterede i fibre med en styrke beregnet på basis af kompositstyrken a 643 MPa, der er tilsvarende styrken af hampegarnet (677 MPa) selvom skånsomme behandlingsmetoder blev anvendt. Plantefiberstyrken så også ud til at stige lineært med celluloseindholdet og var ikke mærkbart afhængig af defibreringsmetoden. Ren cellulose havde dermed en styrke a 850 MPa hvilket er ca. 10 % af styrken på molekylært niveau. Risø-PhD-11 7
Page 1 and 2: Risø-PhD-11(EN) Properties of hemp
Page 3 and 4: Contents Preface 6 1 Resumé 7 2 Li
Page 5: PhD thesis: Properties of hemp fibr
Page 9 and 10: 2.4 Oral presentations Anders Thyge
Page 11 and 12: 4 Introduction Hemp (Cannabis sativ
Page 13 and 14: 4.2 The outline of the thesis The f
Page 15 and 16: The only fertilizer used was 360/48
Page 17 and 18: Temperature [ o C] 35 30 25 20 15 1
Page 19 and 20: A B Figure 7. A: Model of transvers
Page 21 and 22: Figure 8. Lignin (a), pectin (b) an
Page 23 and 24: Figure 11. Microfibril angles (MFA)
Page 25 and 26: Teleman, 1997). The crystal structu
Page 27 and 28: to the computing effort and the sub
Page 29 and 30: Figure 15. The structure of hemicel
Page 31 and 32: fibre mats, which are made by air-d
Page 33 and 34: Figure 18. From fibre filament to a
Page 35 and 36: A B C D Figure 20. Chemical structu
Page 37 and 38: water vapour and air are removed fr
Page 39 and 40: 7 Defibration methods Defibration m
Page 41 and 42: Table 5. Fibre yield and cellulose
Page 43 and 44: a b c Composition [% w/w] 100 Compo
Page 45 and 46: 8 Fibre strength in hemp The streng
Page 47 and 48: 8.2 Effect of pre-treatment of hemp
Page 49 and 50: E-modulus [GPa] 90 80 70 60 50 40 3
Page 51 and 52: Second mode: Failure is controlled
Page 53 and 54: structure, which made much higher f
Page 55 and 56: Table 7. Porosity factors determine
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Thereby, the effective fibre streng
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a b Composite tensile strength σcu
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Table 9. Mechanical properties in a
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a σ c/ρ c [10 3 m 2 /s 2 ] b Ec/
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Fibre strength σ f [MPa] Fibre sti
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11 References Andersen TL, Lilholt
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Kaar WE, Cool LG, Merriman MM, Brin
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Stowell EZ, Liu TS, 1961. On the Me
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Appendix A: Comprehensive composite
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The porosity constants can now be d
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Appendix D: Density and mechanical
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Paper I Changes in chemical composi
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Paper II Hemp fiber microstructure
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ABSTRACT Characterization of hemp f
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METHODS AND TECHNIQUES Treatment of
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2000) and their orientation gave th
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By TEM microscopy, the single fiber
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Table 1. Chemical composition of th
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Table 2. Tensile strength (σ) and
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Morvan, C., Jauneau, A., Flaman, A.
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Paper IV Comparison of composites m
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ABSTRACT Aligned epoxy-matrix compo
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the calculation of volume fractions
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solution (pH 4) for 4 h at 85°C. L
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E ⎛ dσ c ⎞ = ⎜ ⎟ ⎝ dε
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Table 2. Chemical composition, stru
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transverse section of the small hem
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Long fibres that pass through the e
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Figure 6. Effect of composite fabri
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DISCUSSION The defibration of hemp
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This investigation showed that the
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Bos, H.L., Molenveld, K., Teunissen
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Thygesen, A., 2006. Properties of h
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Risø-PhD-11 145
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Risø’s research is aimed at solv
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