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Background/Therms
Materials capable of being decomposed by the action of living organisms. Left to itself, it will be
decomposed by natural processes.
Materials consist of two or more physically distinct phases, which when combined together result in
material with different properties from those of the individual components [1]
Biodegradable composite materials consist of biodegradable polymers as the matrix material and
biodegradable fillers, usually biofibres (e.g.lignocellulose fibres). Since both components are
biodegradable, the composite as the integral part is also expected to be biodegradable [5]
Biodegradable
Composites
Biocomposites
1. Reinforcement/Filler• Natural fibres (cotton, flax, hemp)
• Fibres from recycled wood or waste paper (leaf, pineapple)
• By-products from food crops (Seed)
2. Matrices• Polymers derived from renewable resources
(vegetable oils or starches)
• Synthetic fossil-derives polymers • Virgin or recycled thermoplastics
(PE,PP,PS,PVC)
• Virgn thermosets (unsaturated polyesters, phenol formaldehyde, isocyanates, epoxies)
Biocomposite reinforcement
=
+ matrice
• Hydrophobic (petrochemical)• Hydrophilic (cellulose etc.)
Function of Elements
Function of reinforcement
Provide strength and stiffness
Act as reinforcement in fibre-reinforcement composites
Properties of the composite are controlled by properties of the fillers
Function of matrix
Holds the fibers together
Transmit externally applied loads to the reinforcement
Protect the reinforcement from environmental and mechanical damage
Natural Fibres
Natural fibers
Vegetable Animal Mineral
Seed hair Bast fibers Hard fibres Wool/hair Silk Asbestos
CottonKapokAkon
FlaxHempJute
Ramie
AgaveBananaBromeliaCocos
SheepCamel
Rabbits hair
Mulberry silkCoarse silk
Requirements for high-quality biocomposites
Good mechanical properties (for both the matrix and reinforceing fibre)
Good fibre - matrix adhesion
Low viscosity of polymer matrix at the processing temperature
Develop maximum strenght of material Toughness Compatibility• Hydropfilic fibres (cellulosics)• Hydrophilic polymer matrix (polyesters, ethers) Weak bonds lead to failure, fibre pull-out
Fibre architecture
Geometry
Orientation
Packaging arrangement
Volume fraction
Polymer performance
Enhancement of composite properties
-surface modification
-coating
-derivatization
Careful selection
of polymer matrix and
fillers
Careful selection
of polymer matrix and
fillers
Methods promoting adhesion
Methods promoting adhesion
- hydrophilic fibres + hydrophilic matrix
Factors limiting use of natural polymers and bio-fibres
Low compatibility with
hydrophobic polymer matrices
Thermal sensitivity
Flammability
Cost of
accreditation
Technical,
Commercial,
consumer bariers
limited availabilityirregular fiber
shape
finite fiber length
fiber variability
poor adhesion
Drawbacks
Barriers to uptake
Reasons for commercial interest
• Biodegradable• Renovable row material base• Reduced fossil fuel and resource consumption• Lower greenhouse gas emission• Carbon dioxide reduction in nature• Lower overall emisions and environmental impacts
• Easy designed and tailored to meet different requirements
• Light weight, Low density• High mechanical properties• Strong, Durable• Corrosion resistance• Good insulation and UV capabilities• Flexible• High performance, high value products
• Low cost• Possibility for repalacement of fiberglass, wood and
plastic panels
Properties
Environment
Market
- alternative for traditional materials
Why composites needs to be biodegradable?
Environmental and health concerns
Third world development
Biomimetics
• Growing concern for clean environment• Greater social concern• Sustainable• Waste disposal, recycling• Reduced energy consumption• Legislations
•New materials, new methods
of manufacture• Need for improvement of traditional technologies• Depletion of petrochemical resources• Facing new desires• Responsibility for products
• Plants as natural structures
Trends/Research topics
Mimicking structures of living materials Fillers and fibres for reinforcement and
osteoconductivity Processing of cellular composites,
supercritical gas foaming Biocompatibility (in vitro and in vivo
evaluation of polymer composites) Scaffolds for bone tissue engineering
Aims/future
Obtain a biodegradable, environmentally friendly product
Broadening of biocomposites market for different industrial applications
• Development and production of engineering composite materials made entirely from renewable resources
Optimum properties to meet end use requirements
• Improvement in the mechanical performance of existing biocomposites• Maximise the proportion of renowable resources used while retaining desired material properties• Polymer formulations must be further researched and modified
Development in processing technology
• Optimazing processes parameters.
Intensive cooperation among industries, research institutes and governments
Biodegradable Materials
Density Glass transition temperature
(Tg) Melt temperature (Tm) Water absorption Degradation time Mechanical properties
Important factors for biodegradable materials
Manufacture of biocomposites
1. Hand lay-up2. Filament winding3. Pultrusion 4. Extrusion5. Press moulding6. Injection moulding7. Rotational moulding8. Compression moulding9. Resin transfer moulding10. Sheet moulding compounding
Starch Plastics
• Natural hydrophilic polymer• Consist of linear amylose and branched amylo-pectin• Rapid degradation is an advantage vs synthesized
polymers• Can be made thermoplastic• Products with different properties can be prepared with
change condition of polymerization• Its sensivity to humidity is disadvantage for many
applications• Mainly used in soluble compostable foams
Cellulose acetate
Modified polysaccharide synthesized by the reaction of acetic anhydride with cotton linters or wood pulp
Also from recycled paper and sugar cane
Important factor for CA is Degree of Substitution (DS)
CA is a poor substrate for microbial attacks
CA must be plasticized if they are to be used in thermoplastic applications
CA films have a tensile strength comparable to polystyrene, so CA is suitable for injection moulding
CA is used to produce clear adhesive tape, tool handles, eyeglass frames, textiles and related materials
Soy Plastic
Soybeans typically consist of 20% oil and up to 55% Protein
Discrete groups of protein (Polypeptides) contains 38% non-polar, non-active amino acid residue and 58% polar and reactive
Soy protein has unusual adhesive properties
Dried soy plastics display high modulus
Blending with polyphosphate filler greatly reduced its water sensitivity
Aliphatic Polyesters
Can be classified in two groups regarding the mode of bonding of constituent monomers
• Polyhydroxyalkanoates – polymers of hydroxy acid
• poly(alkylene dicarboxylate)s – synthesized by polycondensation reaction of diols and dicarboxylic acids
• hydroxy acids are classified into α-, β- and ω-hydroxy acids in respect of bonding position of the OH group
Aliphatic Polyesters
Poly(α-hydroxy acid)– Poly(glycolic acid) – PGA
– Poly(lactic acid) – PLA
Poly(β-hydroxyalkanoate)s – PHAs– Poly(β -hydroxybutyrate) (PHB) (commercial name Biopol)
– Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)
Poly(ω-hydroxyalkanoate)– Poly(ε-caprolactone) – PCL
• Poly(alkylene dicarboxylate)– Poly(butylene succinate – PBS
– Poly(butylene succinate-co-butyleneadipate) – PBSA
– Poly(ethylene succinate) – PES
Building industry (1)
Particle boards based on sunflower stalks
It is possible to produce particleboards from the chips of sunflower stalks alone by using urea-formaldehyde adhesives.
Sufficient mechanical properties for this application however increase in the sunflower particles decreases mechanical strength.
Journal of COMPOSITE MATERIALS, Vol. 39, No. 5/2005
Building industry (2)Soy oil/cellulose fibers composites for roofs
Composite Structures 74 (2006) 379–388
MedicineTi/polymer biocomposite implant
Journal of Materials Processing Technology 197 (2008) 428–433
Recycling
Biodegradation:
UV degradation weight loss of different starch biocomposites (5 % glycerine)
Samples of sisal starch composites at fiber content of 5% w=w and at glycerine contents of 12.5% w=w at 2, 5, 7 and 9 days of exposition in agar medium.
The recycling concept:
The big challenge for the future!!!
International Journal of Polymeric Materials, 55:1115–1132, 2006
Conclusions:
• More composites materials are considered as biocomposites
• Biocomposites market is still improved and broaded
• Further research still need to be continued
• Effords involved in research and production is a big step in the right direction-eco direction thus biocomposites still will get much attention in the future
References:• [1] J.Sci Food Agric 86, 1781-1789, 2006• [2] Macromol. Mater. Eng. 276/277, 1-24, 2000• [3] Progress in Polymer Science 34, 125–155, 2009• [4] Polymer Degradation and Stability 88, 138-145, 2005• [5] Carbohydrate Polymers 56,111-112, 2004• [6] Caroline Baille, Green composites, Polymer composites and the environment• [7] Biodegradable composites based on lignocellulosic fibers. An overview - Kestur G. Satyanarayana et al –Composites 2008• [8] Mechanical properties of poly (butylene succinate) (PBS) biocomposites reinforced with surface modified jute fibre”, Lifang Liu et al – 2008• [9] Composite Interfaces, Vol. 8, No. 5, pp. 313–343, 2001• [10] Journal of Composite Materials, Vol. 39, No. 5, 2005• [11] Composite Structures 74, 379–388, 2006• [12] Macromol. Mater. Eng. 291, 449–457, 2006• [13] Journal of Materials Processing Technology 197, 428–433, 2008• [14] International Journal of Polymeric Materials, 55, 1115–1132, 2006
Thank you for your attention!!!!