PEPSPEPS

Polyethylene Pipes Systems

The Environmentally Friendly Pipes

Lina Garcia Kathy Bui Ian Matts William Kyei-Manu

Agenda1. Background

2. Goals

3. Device Design

4. Polymer Science Theory

5. Sample Testing

6. Cost Analysis

7. Gantt Chart

8. Acknowledgement

Background

• Food and water shortages in developing parts of the world such as Africa are common

• Many small agricultural operations in developing countries are stagnant due to countries are stagnant due to lack of resources

• Excess of unrecycled plastic shopping bags in many parts of the world is a wasted resource

Picture from www.defeatpoverty.com

Picture from www.greencrawler.com

Irrigation Kits on Current Market

The International Development Enterprises Krishak Bandhu Family Nutrition Kit: $6.00

Source: http://www.ide-india.org and http://www.ideorg.org

• Includes 20 m of tubes to irrigate 20 m2 of land

• Water Height: 1.5 m• Pressure: 0.15 atm

GoalsWe aim to produce irrigation tubing via a method that is:• Low tech• Low cost• While using recycled materials for tubes

Our final deliverable are:• A method to produce irrigation tubing• A method to produce irrigation tubing• An irrigation tube prototype

Specifications of tube prototype:• 6-25 mm in diameter• can scale up to 20 m per piece• can withstand at least 0.15 atm of water pressure

Design Considerations

1. Production Method• Hot gas welding, heat welding, blow

extrusion

2. Heat Source• Resistive heater, hot coals, hot water

Small image from first update “choices to make” slide

3. Construction Materials• Steel, Aluminum, plastics

4. Starting Material• 100% recycled vs. partially recycled HDPE

minco.com

larusse.com

Device Design

Key design features:

•Double seam• Aids in continuous processing

•Aluminum• High thermal conductivity

•Lack of contact•Lack of contact• Avoid friction-associated problems

•No monolithic layers• Fewer processing steps

•Heating away from rollers• Ease of pipe fabrication

Actual Device

Notable Features:

•Fixed distance between rollers

•Gears to coordinate roller rotation.

Hand crank

Resistive Heaters

rotation.

•Hand crank for ease of use

•80-20 base allows for adjustment

Aluminum rollerswith teflon tape

Driven gear

Further Improvements

Potential Future Work:

•Interchangeable rollers

•More precise machining

•Lower cost of device

•Motorized rotation

•Take away variac

Theoretical ranges of relevant parameters:

•Temperature :

94°C to 156°C

Sample Production Parameters

94°C to 156°C

•Velocity :

2 mm/s - 100+ mm/s

•Pressure:

0 psi - 25+ psi

Weld Strength Model

Non-Fickean diffusion of polymer end chains

σw = strength of weldσm = strength of raw materialv = velocityT = processing temperature

Image Source: http://nobelprize.org

Peel Test

ASTM D6392-08:"Standard Test Method for Determining the Integrity of Nonreinforced Geomembrane Seams Produced Using Thermo-Fusion Methods”Methods”

Extension rate = 50 mm/minWidth = 25 mm

Peel Test Results

Temp~130°CV~6.3mm/s

Minimum Strength

Pressure2 m of tube, tested vertically, water source at 2 m above ground

Hydrostatic pressure: P = ρgh

where ρ is the density of the fluid, g is the gravitational acceleration, h is the height of gravitational acceleration, h is the height of the fluid column.

Stereomicroscopy

8-layer weld under 1x magnification

1mm

Same 8-layer weld under 5x magnification

1mm

Scanning Electron Microscope (SEM)

8-layer weld under 17x magnification

SEM Elemental AnalysisC

CaCa

O NaAl Cl

Cost Analysis

Product Cost per 20m tube

PEPS $1.15

Krishak Bandhu Family Nutrition Kit $4.00 (Est.)

Past 3.042 Project $98

•Fixed Cost (Cost of device, maintenance etc) ~ $290-$300•Energy Cost = $0.20 per kWh•Labor Cost =$2.75 per day (working for 250 days per year)•Estimated Kits per year ~ 1100 kits

Strategic Plan

Decision Tree Results:Plan

Produce on Large Scale Plant

Capacity1100 units/yr

Period One (First 5 years)

Scale: Large Scale

Price: $1.3

Period Two (Subsequent 5 years)

Low Demand Very Large Scale; $1.5

Medium Demand Very Large Scale; $1.51100 units/yr Medium Demand Very Large Scale; $1.5

High Demand Very Large Scale; $1.5

Initial Investment$1,950 Return on Investment if we use this plan

Market Share Profit

Low $394

Medium $1,609

High $2,060

Gantt Chant

Acknowledgement

We would like to thank the following people for their support and guidance throughout the project:

Mr. David BonoMr. Harlan BreindelProf. Yet-Ming ChiangProf. Yet-Ming ChiangDr. Suzanne T LaneDr. Joseph ParseMs. Joy C PerkinsonDr. Christoph SachsMr. Mike TarkanianMs. Yinlin XieMr. Tom Geyer from AMPAC

Questions?

Thermal Analysis

Thermal Properties

Thermal Analysis via Differential Scanning Calorimetry (DSC)

• Tested 6 different bags

• Average melting temperature, T = 124.9 ± 1.3°C• Average melting temperature, Tm = 124.9 ± 1.3°C

• Softening point, ~105-115°C

• Average heat capacity, Cp = 2.1 ± 0.6 kJ/kg°C1

1. W. Martienssen, H. Warlimont, Springer Handbook of Condensed Matter and

Materials, 2005, XVIII, 1120, p. 1025

Tube Strength

•Water Pressure:

•Minimum Weld Strength:Source: Pipeline Engineering Design

Weld Failure Modes

The ASTM standards specify different failure modes for peel test:

X-Ray Diffraction Test ParametersNo ASTM Standards found for measuring polymer crystallinity using XRD

Equipment:PANalytical Multipurpose Diffractometer in 13-4027

Parameters:•5°to 70°•90 min/sample•At 40mA•Max penetration depth exceeded thickness of entire sample

X-Ray Diffraction Data

Heat Transfer Model

Will temperature at contact Will the heating requirement bepoint be high enough? reasonable when considering losses?

Heat in Heat out

Yes!

Yes!

Heat conduction approximations

For:• Ts=100 C, t = 48 sec• Ts=102 C, t = 13 sec• Ts=110 C, t = 2 sec

Peel Test ParamtersASTM D6392-08: "Standard Test Method for Determining the Integrity of Nonreinforced Geomembrane Seams Produced Using Thermo-Fusion Methods”

Geomembranes are composed of Polyethylene of various densities, Polyvinyl Chloride, or Polypropylene.

Variable ASTM Actual

Sample Width 25 mm 25 mm

Sample Height 150 mm 100 mm

Extension Rate 50 mm/min 50 mm/min

Grip 25 mm x 25 mm 25 mm x 25mm

Tube Geometry Model

Young’s Modulus E ~180MPaYield Strength in tension ~4.4 MPaDiameter ~ 0.75''Thickness ~ 8 layers of bag ~ 0.517mmFactor Of Safety: 1Water pressure ~ 0.15 atm

PE Relaxation Time

Robelin-Souffach et al. Relationship between the Relaxation of Polyethylene Coils in the Melt and the Molecular Weight Distribution. Macromolecules, 1984.

Non-Fickean Diffusion

Reptation Model• Reptation time = avg time for a chain to move a distance equal to its radius of gyrationo

o trep for PE of Mw=104 g/mole is in the

• Diffusion scales as t1/4

1. Robelin-Souffach et al. 1984

o trep for PE of Mw=104 g/mole is in the order of 10 seconds1

Weld Strength

Heat Affected Zone (HAZ)

• Processing parameters also determine microstructure

Cost of Device Production

Aluminum rollers~$80Heating element ~ $70Insulation ~ $10Machining(5hours X $10/hour) ~ $508020 Aluminum Extrusion ~$208020 Aluminum Extrusion ~$20Steel rods ~ $40 Overhead Cost (nuts/bolts,shipping, etc) ~ $20

Total Cost of Prototype Device ~ $290

FTIR Results

FTIR Results

• Peaks observed comparable to those obtained from literature2

• No significant traces of additives• Processed Bag show lower peak intensity2. Table adapted from “Physical and mechanical behaviour of hot rolled HDPE/HA composites” by A. Pandey, E. Jan, P.B. Aswath,

published 12, April 2006.

Stress-Strain Response

Sample Peel Test: Sample 6A

30

40

Load (N)

0

10

20

0 10 20 30

Load (N)

Extension (mm)