Fungal Modifications of Chitosan Adhesives for Manufacturing Wood Composites

Transcription

1 Fungal Modifications of Chitosan Adhesives for Manufacturing Wood Composites Dian-Qing Yang Yaolin Zhang Xiang-Ming Wang Martin Feng Location: Date: FPS Wood Adhesives, Toronto October 11, 2013

2 Introduction Chitin is the second most abundant natural biopolymer derived from crustaceans, insects and cell walls of fungi Chitin and chitosan are aminoglucopyrans composed of N- acetylglucosamine (GlcNAc) and glucosamine (GlcN) residues Chitosan is a product derived from N-deacetylation of chitin in the presence of hot alkali Structure of chitin 2

3 Introduction Chitosan is soluble in weakly acidic aqueous solutions and possesses adhesive property Chitosan has the properties to rapidly clot blood and it has been used in medical bandages and as an effective biological adhesive with surgical applications As an adhesive, chitosan alone is unable to be used for manufacturing wood composites because of its low bonding property that can t meet the required product quality Structure of chitosan 3

4 Modification of chitosan GlcN = glucosamine, GlcNAc = N-acetyl glucosamine, LMWC = low-molecular-weight chitosan from Reactive & Functional Polymers 68 (2008)

5 Objectives Biologically modification of chitosan for wood applications: using selected fungal species to modify chitosan and improve its bonding property making non-formaldehyde resin with modified chitosan making enhanced UF and PF resins with biologically modified chitosan 5

6 Materials and Methods Characters of chitosan used in the test Parameters Appearance Off-white Form Flake Moisture 5.6% Ash 0.197% Protein < 0.2% Insoluble matter < 1% Degree of deacetylation 86.6% Toxic heavy metals (As, Cd, Hg, Pb) < 5ppm Viscosity (1% wt in 1% acetic acid) 307 cps Microbial contamination 890 CFU/g Characters 6

7 Materials and Methods Fungal species used for chitosan modification Trichoderma harzianum Rifai (FTK160D) Trichoderma viride Pers.:Fr. (FTK161D) Gliocladium roseum Bainier (FTK321U) All these fungal isolates came from the Culture Collection of Wood-inhabiting Fungi of FPInnovations, Québec, Canada Cultures were maintained in liquid nitrogen container at -196 C before use. 7

8 Materials and Methods Modification of chitosan 2% of chitosan in V8 medium, ph 6 Inoculation of each fungus in the medium Incubation on a shaker (125/rpm) at 25 C for 21 days The slurry of chitosan was filtered, washed dried at 50 C to dryness 8

9 Materials and Methods Preparation of modified chitosan adhesives Making 3% of modified chitosan resin in 1 w% acetic acid solution Mixing commercial PF resin (phenolic plywood resin 57%) with10% of modified chitosan powder Mixing commercial UF resin (UF plywood resin 60%) with 5% of modified chitosan powder 9

10 Materials and Methods 3-layer plywood preparation Yellow birch veneer (1.5 mm thickness) Double-glue-line Spread rate (2 g per 100 cm 2 veneer) Temperature: 140 C Pressing: 1500 KPa. Time: 14 min Lap-shear strengths were determined by a MTS Alliance RT/50 testing machine according to the CSA Standard Method

11 Shear Strength (KPa) Results Modified chitosan has better performance than unmodified chitosan Chitosan adhesives Dry Wet C 321U 161D 160D Resin C: unmodified chitosan 11

12 Shear Strength (KPa) Shear Strength (KPa) Results UF/Chitosan adhesives Resin PF/Chitosan adhesives Resin (a) (b) Legends: 1: acidic solution of unmodified chitosan 2: UF(or PF) resin with unmodified chitosan 3: UF (or PF) resin with fungi modified chitosan III (321) 4: UF(PF) resin with fungi modified chitosan I (161) 5: UF (PF) resin with fungi modified chitosan II (160) 6: UF (PF) resin (control). (a) UF resin (b) PF resin 12

13 Results Biologically modified chitosan alone can be used as wood adhesive Chitosan modified by different fungi can enforce the UF adhesive performance Chitosan modified by different fungi can also enforce the PF adhesive performance 13

14 Conclusions Chitosan was biologically modified with the three selected fungal species Modified chitosan was able to be used alone or combining with currently used UF or PF resins to manufacture composite panels Modified chitosan adhesive is possible to be used as a biological glue in other fields. 14

15 Acknowledgements Research efforts were made possible thanks to the financial support of the federal government through the Transformative Technologies Program. 15

16 Thank You for Your Attention Any Question? 16