Natural Materials for Low Cost Plastic Development Alan K ...€¦ · Rice husk Milkweed seed Mulberry silk Spider silk Bagasse Esparto Canary grass. Natural Fibers Strength (Mpa)

Natural Materials for Low Cost Plastic DevelopmentNatural Materials for Low Cost Plastic Development

Alan K.T. LauFIMechE FHKIE FIMMM FIoM FIEAust

Professor and Director

Product Testing and Analysis CentreDepartment of Mechanical EngineeringThe Hong Kong Polytechnic UniversityKowloon Hong Kong

Natural Materials and their Composites

•Product Development

•Biomedical Applications

• Type of Natural Fibre

• Mechanical Properties

• Preprocessing Treatment

• Recycled Fibre Composites

• Industrial Applications

Focus

Fibres

Natural fibres Man‐made fibres

Plant‐based fibres(Cellulose or lignocellulose fibres)

Animal‐based fibres(Protein)

Wood Cane, grass & reed

Stalk Leaf Bast(Stem)

Seed Fruit

Hard Wood(Oak)

Soft Wood (Pine)

Bamboo

Phragmites Communis

Elephant grass

Wheat

Maize

Barley

Rye

Oat

Rice

Sisal leaf

Abaca leaf

Henequen

Pineapple leaf

Palm leaf

Flax

Hemp

Jute

Ramie

Kenaf

Cotton

Kapok

Coir

Mineral

Wool &Hair

Lambswool

Goat hair

Angora wool

Cashmere

Yak hair

Horse hair

Flight feather

Down feather

Silk

Tussah silk

Fibrous brucite

Asbestos

Wollastonite

Inorganic whiskers

Human hair

Rice husk

Milkweed seed

Mulberry silk

Spider silk

Bagasse

Esparto

Canary grass

Natural FibersStrength

(Mpa)Elongation at Break

(%)E (GPa)

Kenaf 295-1191 3.5 2.86

Coir 106-175 14.21-49 4-6Bamboo (*) 100 - 600 ---- 3 - 15

Sisal 80-840 2-25 9-38

Palm (*) 248 3.2 25

Banana 529-914 3 27-32

Hemp 310-900 1.6-6 30-70

Pineapple 170-1627 2.4 60-82

Spider silk 875-972 17-18 11-13

Cocoon silk (*) 610-690 4-16 15-17

Wool 120-174 25-35 2.3-3.4

Human Hair(Nikifordis et al 1992)

--- --- 3.43 (elderly)4.46 (Young)

Mechanical Properties

P. Wambua et al. Comp. Sci. Tech. 2003; 63: 125--1264

Vf = 30%, E-glass/PP (Vf=30%) = 32 MPa

Plant-based fibre E-glass Hemp Jute Coir (Coconut)

Sisal Banana Bamboo

Density (g/cm3) 2.55 1.48 1.46 1.25 1.33 1.35 0.89

Tensile Strength (MPa) 2400 550-900 400-800 220 600-700 600 341 - 381

E-Modulus (GPa) 73 70 10-30 6 38 17.85 19.67

Elongation at Failure (%) 3 1.6 1.8 15-25 2-3 3.36 1.73 - 5.2

Moisture Absorption (%) --- 8 12 10 11 10.71 10.14

Hemp

Jute

Coir

Sisial

Banana

Bamboo

Ultimate Tensile Strength of PP = 19 MPa

Pineapple leaf fibre (PALF) in soy-based biothermoplastic.

Liu et al .“Green” composites form soy based plastic and pineapple leaf fiber: fabrication and properties evaluation. Polymer. 2005;46:2710-2721

PALF bundle in 100m(with compatibilizer (PEA-g-GMA)

Bamboo fibre• Low water absorption• Low cost• High strength• Biodegradable• 6-8 months to grow up

Pre-treatment

Polar surface of the natural fibre • Hydrophilic fibre

– Water absorption and diffusion

• Hydrophobic plastic

– Incompatible

– Poor interfacial adhesion1. Expansion of wet fibre (grey region indicating

stress in the matrix

2. Wet composite after stress has been released by molecular relaxation processes

3. Contraction of the fibre during drying

Results

• Decrease the mechanical properties

• Accelerate the degradation

Biopolymer• Starch type

• Cellulose

• Chitin and Chitosan

• Bacterial polymer

Biodegradation Modes• Microorganism

• Fungi

• Bacteria (aerobic activity)

• Enzymes

• Catalytic activities

http://www.devicelink.com/mpb/archive/98/03/002.html

Polymer Melting Point (°C)

Glass-Transition Temp, Tg (°C)

Modulus (GPa)a Degradation Time (months)b

PGA 225—230 35—40 7.0 6 to 12

LPLA 173—178 60—65 2.7 >24

DLPLA Amorphous 55—60 1.9 12 to 16

PCL 58—63 (—65)— (—60) 0.4 >24

PDO N/A (—10)— 0 1.5 6 to 12

PGA-TMC N/A N/A 2.4 6 to 12

85/15 DLPLG Amorphous 50—55 2.0 5 to 6




Polyester 260 175 1.2 to 4.5 Recyclable

Epoxy --- 182 to 206 3.1 Reusebale #

LDPE 98 to 115 -90 to -25 200 – 400 MPa Recyclable

PP 160-180 - 25 to -20 1 to 1.4 Recyclable

a Tensile or flexural modulus.

b Time to complete mass loss. Rate also depends on part geometry.

Silks (from cocoons and spiders) are kinds of animal‐based nature fibres which are high strength, bio‐degradable, commercially‐available and low cost.

Silk Fiber

This outer layer, silk sericin is a natural macromolecular protein derived from cocoon Bombyx mori, and used to ensure the cohesion of the cocoon by gluing silk threads together. The protein resists oxidation, is antibacterial, ultra‐violet (UV) resistant, and absorbs and releases moisture easily.

The cocoon shells subjected to increasing heat treatments. (starting from left to right): untreated; at 190C; 250C; 350C; 450C and 550C for over 0.5 hr.(Zhang et al. J. Appl. Poly. Sci. 2002; 86: 1817‐1820)

Animal‐based Biocomposites

Materials UTS (MPa) Young’s Modulus (GPa) % Strain at break

B. mori silk 610-690 15-17 4-16

Spider dragline silk 2000 30 17-18

Collagen 0.9-7.4 0.0018-0.046 24-68

Collagen X-linked 47-72 0.4-0.8 12-16

PLA 28-50 1.2-3.0 2-6

Tendon (compose mainly of collagen) 150 1.5 12

Bone 160 20 3

Kevlar (49 fibers) 2000 100 2.7

Synthetic Rubber 50 0.001 850

Mechanical properties of silks (silkworm and spider dragline), biomaterial fibers and tissues

Mechanical Property Tests for Silk/PLA Composites

02468

101214161820

Young's Modulus (GPa) Hardness (Hv) Flexural Modulus (GPa)

Pure PLA

PLA (5mm 5% w t.% silk)

Tensile strength and modulus of PBS and five silk/PBS biocomposites(Lee et al. Comp. Sci. Tech. 2005; 65:647‐657)

Chicken FeatherFiber

Samples Modulus of Elasticity (MPa)

Pure PLA 3819

CFF/PLA (fiber from upper (flight) portion of feather)

3492

CFF/PLA (fiber from lower (down) portion of feather)

4184

SamplesFailure Extension

(mm)Flexural Modulus

E (Gpa)

Percentage Increase

(%)

PLA 3.85 3.96 0

HEMP 19.19 4.32 10.3

CFF 2.73 4.06 4.22

Silk 15.67 4.35 11.1

Bamboo 2.67 4.32 10.4

Interfacial Bonding Properties

Basically, the mechanical and thermal properties of natural fibre composites are governed by their interfacial bonding properties. Up to date, many studies have been conducted going along this direction to determine or improve their bonding strength.

• Nanoindentation ‐‐ ??• Microdroplet test• Single fibre pullout test• Microbond test

• Silane treatment (chemical coupling) • Oxidization• Surface cleaned by methanol and benzene• Natural fibre surface layer (enhancement of the bonding strength with PE – coconut (waxy layer))

Manufacturing Processes

• Injection moulding (pellets)

• Compression moulding (mat and fabrics)

• Resin transfer moulding (mat and fabrics)

• Hand lay‐up (chops, mat and fabrics)

• Spray lay‐up (mat and fabrics)

• Infusion and vacuum bagging (mat and fabrics)

Tradition shear‐lag models

• Surface Configuration– Chemical bonding

– Mechanical interlocking

– Polar Hydroxyl (OH) groups

• Hydrophilic – Natural Fibre

• Hydrophobic ‐ Polymer Matrix

• Wettability – Natural Fibre (from filaments to a fibre)

• Degradation at adjacent region of the fibre

• Manufacturing processes

Interfacial Bonding PropertiesDuigou et al. Comp. sci. tech. 2010; 70: 231‐239

Surface of coconut fibre with and without removing waxy layer(Brahmakumar et al. 2005; 65: 563‐569)

Li et al. Comp. Pt A. 2008; 39: 570‐578

• Advantages– Low‐cost and light weight (reduction of the cost of products)

– Non‐abrasive nature (less impact to the environment)

– High specific properties and biodegradability

• Limitations– Moisture absorption

– Poor wettability

– Large scattering in mechanical properties

– Not sufficient understanding of mechanisms controlling their mechanical behaviour and failure modes

– Difficulties in modelling (FEM and theoretical analysis)

– Damage detectability• Acoustic emission

• Embedded sensor technologies

• Thermo‐graphical technologies Sisal fibre (#)

# F.d.A. Silva et al. / Composites Science and Technology 68 (2008) 3438–3443

Industrial Collaboration

• The use of recycled plastics for product development– Design competition with University’s students;

• Design competition

• Factory Visit

• Seminars

• Consultation

– Establishment of “Standard” for quality control of materials;

• Collaboration

– Investigation on the basic properties of natural filler reinforced recyclable plastics

• Research Projects

Recyclable Plastics and their Composites Provide Lightweight andRecyclable Plastics and their Composites Provide Lightweight andEco Solutions for Product, Building, Construction, TransportatiEco Solutions for Product, Building, Construction, Transportation on

and Automobile Engineering Industriesand Automobile Engineering Industries

Documents

Natural Materials for Low Cost Plastic Development Alan K ...€¦ · Rice husk Milkweed seed Mulberry silk Spider silk Bagasse Esparto Canary grass. Natural Fibers Strength (Mpa)