Mechanical Evaluation of Recycled Post-Consumer

Foamed Polystyrene Food Ware as a Possible

Wood Substitute

by

Hanzel M. Orlanda

A Thesis Submitted to the School of Chemical Engineering and Chemistry in Partial Fulfillment of the Requirements for the Degree

Bachelor of Science in Chemical Engineering and Chemistry

Mapúa Institute of Technology July 2005

ii

APPROVAL SHEET

This is to certify that we have supervised the preparation of and read the thesis prepared by Hanzel M. Orlanda entitled Mechanical Evaluation of Recycled Post-Consumer

Foamed Polystyrene Food Ware as a Possible Wood Substitute and that the said thesis has been submitted for final examination by the Oral Examination Committee.

Marilen M. Martin Michelle Almendrala, PhD.

Thesis Adviser Course Adviser As members of the Oral Examination Committee, we certify that we have examined this thesis, presented before the committee on July 18, 2005, and hereby recommend that it be accepted as fulfillment of the thesis requirement for the degree in Bachelor of Science in

Chemical Engineering and Chemistry.

John Ysrael Baluyut, M.S. Engr. Richard Vinluan, M.S.

Panelist Panelist

This thesis is hereby approved and accepted by the School of Chemical Engineering and Chemistry as fulfillment of the research proposal requirement for the degree in Bachelor

of Science in Chemical Engineering and Chemistry.

Luz L. Lozano, M.S.

Dean, School of Chemical Engineering and Chemistry

iii

ABSTRACT

The numerous advantages of foamed polystyrene (FPS) food ware over other food service wares increase its demand in food packaging services. The large demand for these products resulted to an accumulation of about 4-5 tons per day of post-consumer waste FPS in Metro Manila. The product made from recycling waste FPS in used oil is a probable wood substitute. This thesis aims to evaluate the mechanical properties of the recycled FPS as a wood substitute and to determine the waste FPS to oil ratio that would produce the strongest recycled product. Varying proportions of waste FPS were melted at temperatures of 160, 170, 180, 190, or 200 ºC. The resulting products were evaluated of their compressive strength, modulus of rupture, and hardness. The ratio of 3 parts waste FPS to 1 part used oil yields the strongest product. The compressive strength and the modulus of rupture are increasing with temperature. For both of these tests, the 3:1 ratio tolerates the greater load. The hardness of the materials have hardness ranging from 4-5 or equivalent hardness of fluorite or apatite.

iv

ACKNOWLEDGEMENT

The researcher graciously appreciates the assistance of those through whose

helpfulness made this research possible. To Engr. Manuel de Guzman and Mr. Jun

Braganza, thank you for giving this topic. To the Industrial Technology Development

Institute headed by Mr. Manny Navarro and to Sir Nelson and Sir Dondie, thank you for

helping and providing the materials needed in pursuance of this research.

To Engr. Roel John Judilla , Dean of School of Mechanical Engineering of

Mapúa Institute of Technology, Engr. Joselito Necessito, Sir Vergel and Sir Randy,

thank you for testing the recycled FPS.

To Mrs. Marilen Martin, thank you for being the adviser. To Dr. Michelle

Almendrala, thank you for all the help and assistance. To Sir John Baluyut, thank you for

the support, advice, and guidance in the aspiration to finish this thesis.

To all the friends of the researcher especially to mang seb, katkat, lorraine,

keywa, kat o, rica, karen o., karen g., rose, joy e., ger, and yas and to the fellow CCE

students karen e., mhel e., rannel, and mariz, thank you for the inspiring words of

encouragement that led to the completion of this thesis.

Thank you Tatay, Nanay, and Peewee for all the love and comfort you provide.

Thank you Mama, Tita Beth, Tita Eny, and cousins for the cheers and support. And most

of all, thank you to almighty God for giving the researcher all these wonderful people.

v

TABLE OF CONTENTS

APPROVAL SHEET.......................................................................................................... ii ABSTRACT....................................................................................................................... iii ACKNOWLDGEMENT.................................................................................................... iv TABLE OF CONTENTS.................................................................................................... v LIST OF FIGURES .......................................................................................................... vii LIST OF TABLE ............................................................................................................. viii Chapter 1: INTRODUCTION ......................................................................................... 1 Chapter 2: REVIEW OF RELATED LITERATURE ..................................................... 4

Polystyrene..................................................................................................... 4 Foamed Polystyrene....................................................................................... 4 Mechanical Properties of Wood..................................................................... 8

Chapter 3: MECHANICAL EVALUATION OF RECYCLED POST-CONSUMER

FOAMED POLYSTYRENE FOOD WARE AS A WOOD SUBSTITUTE 9 Abstract .......................................................................................................... 9 Introduction.................................................................................................... 9 Methodology ................................................................................................ 11

Preparation of the Sample ...................................................................... 11 Hardness Test ......................................................................................... 13 Compressive Strength Test..................................................................... 13 Modulus of Rupture Test........................................................................ 14

Results And Discussion ............................................................................... 15

Melting of Waste FPS ............................................................................ 15 Hardness Test ......................................................................................... 15 Compressive Strength Test..................................................................... 15 Modulus of Rupture Test........................................................................ 16

Conclusion ................................................................................................... 17

vi

Recommendation ......................................................................................... 18 References .................................................................................................... 18

Chapter 4: CONCLUSION............................................................................................ 19 Chapter 5: RECOMMENDATION ............................................................................... 20 REFERENCES ................................................................................................................. 21

vii

LIST OF FIGURES

Figure 2.1. Polystyrene mer unit........................................................................................ 4

Figure 2.2. Photon micrograph of FPS ............................................................................. 5

Figure 3.1. Used cooking oil............................................................................................ 12

Figure 3.2. Crushed waste FPS........................................................................................ 12

Figure 3.3. Cutting of recycled FPS................................................................................. 13

Figure 3.4. Shimadzu Universal Testing Machine........................................................... 14

Figure 3.5. Universal Testing Machine............................................................................ 14

Figure 3.6. Comparison of maximum strengths of 2:1 and 3:1 ratio vs. temperature ..... 16

Figure 3.7. Comparison of modulus of ruptures of 2:1 and 3:1 ratio vs. temperature..... 17

viii

LIST OF TABLES

Table 2.1. Mechanical properties of some commercially important wood........................ 8

Table 3.1. Maximum stress of 2:1 and 3:1....................................................................... 16

Table 3.2. Mechanical properties of some commercially important wood...................... 17

1

Chapter 1

INTRODUCTION

The first Earth Day, which occurred in 1970, signaled the development of a new

level of awareness and concern about the environment (Richardson, 1997). Since then

numerous efforts are being pursued to help minimize, if not eradicate, non-earth friendly

activities. The anti-litter campaigns during the 1970s, the Resources Conservation and

Recovery Act (RCRA) passed by the federal government in 1976 which promotes reuse,

reduction, incineration of materials, and several groups and alliances were formed to save

used or waste materials for reprocessing into something useful, generally known as

recycling.

Polystyrene (PS) is the most recycled form of single-service food packaging

(PSPC, 1996). Fast food chains in Metro Manila like Jollibee, McDonald’s, Wendy’s,

and Chowking, use foamed polystyrene (FPS) for food packaging. Its numerous

advantages over other food service wares – low cost, free of odor and taste, excellent

thermal insulator, chemically inert, good dimensional stability and rigidity, and low

moisture absorption – increase its demand in food packaging services. However, the large

demand for these products resulted to an accumulation of waste FPS in dumpsites. In

particular, about 4-5 tons per day of post-consumer waste styropacks are being generated

in Metro Manila (M. Navarro, 2004). The non biodegradability of the waste FPS poses

an additional problem to its increasing volume. It does not break down, it clogs

drainages, and it stays in landfills for a long time which causes serious environmental

problems.

2

Because of the issues in recycling PS food packaging wastes, several recycling

programs are being studied and implemented to reduce these PS wastes that will be

economically sustainable. According to Raymond Ehrlich, Director of Environment,

Health and Safety for the Polystyrene Packaging Council, in about 10 years, total

polystyrene recycled essentially grew from zero pounds per year to approximately 50

million pounds per year.

In the Philippines, an FPS recycling plant was set up in 1995 in Sta. Maria,

Bulacan by the Polystyrene Packaging Council of the Philippines, Inc. (PPCP) to help

minimize FPS wastes. Its collection of FPS wastes has extended to schools within the

area. One of the problems that occurred in this program is the high transportation cost of

the pick-up and delivery of the wastes to the recycling plant. This made FPS recycling

unattractive.

The Industrial Technology Development Institute (ITDI) under the Department of

Science and Technology (DOST) helps in discovering innovations in FPS recycling.

“Melting of Waste FPS in Used Oil” is a project of ITDI that was pursued in

collaboration with PPCP. The project aims to develop suitable processing/recycling

techniques in order to convert post-consumer waste FPS into value added functional

products (M. Navarro, 2004). The recycled product is found to be a potential substitute

for wood. ITDI has already made chairs and tables out of this technology. Yet there is a

lack of information in the waste FPS to oil ratio and the heating temperature that would

produce the strongest recycled product.

3

This thesis aims to evaluate the mechanical properties of the recycled FPS as a

probable substitute for wood and determine the waste FPS to oil ratio that would produce

the strongest recycled product.

This thesis will help in the reduction of waste FPS and frying oil in the

environment. It will benefit the FPS producers, food chain owners, the community and

the government.

The focus of this thesis is in the evaluation of the mechanical properties of

recycled FPS. The resistance to weathering exposure and the mechanism of the reaction

of used frying oil with the FPS is no longer assessed.

4

Chapter 2

REVIEW OF RELATED LITERATURE

Polystyrene

Polystyrene (PS) is a linear polymer composed of a long chain of styrene mer

units (Figure 2.1). According to A. Blaga, when heat is applied to a mass of polymer

having linear or branched molecules, the material will soften at a certain temperature and

flow. The melt temperature or the flow temperature for amorphous polymers of PS is

from 240 – 280 ºF (115.56 – 137.78 ºC). This temperature is very important in this thesis

because it is used as the basis for the loading temperature of the waste FPS.

Figure 2.1. Polystyrene mer unit

Foamed Polystyrene

Foamed polystyrene products are usually made from polystyrene resin that

contains a blowing agent (usually pentane, CO2, or butane). The blowing agent is injected

into the extruder and then into the die. Then the resin with blowing agent is “prepuffed,”

stored to allow equilibration of the expanded material and then processed into food

wares. In the final process, some additional expansion as well as molding occurs. The

H H

H

C C

5

blowing agent gradually diffuses out and is replaced by air. This makes the foamed

polystyrene 95% air and 5% of the plastic matrix (Figure 2.2).

Figure 2.2. Photon micrograph of FPS

Foamed polystyrene is easily recyclable because it is a thermoplastic.

Thermoplastic polymers soften when heated and harden when cooled. This heating-

cooling cycle can be repeated many times without chemical change, making it ideally

suited for forming without plasticizers or significant other additives in a wide variety of

products (PSPC, 1996).

Polystyrene Packaging Council in Washington DC, USA and Mega Packaging

Corporation in Laguna, Philippines are two companies that use high-temperature

machines to recycle FPS. PSPC uses an extruder at a temperature 400-440°F to melt the

washed, dried, and grinded polystyrene. The melted polystyrene is formed into pellets

and finally cooled in a water bath. Mega Packaging Corporation follows the same

principle but uses a different melting unit. A heated screw conveyor that is placed inside

6

their Mobile EPS recycling equipment melts the polystyrene chips. The process is easy to

conduct but the products formed from this process are too brittle.

Aside from the use of temperature to recycle FPS, reagents can be utilized to

recycle polystyrene. Williams and Cleereman provided a group listing of some of these

reagents (Table 10-17, Williams & Cleereman, 1952). One of the most coveted recycling

procedures that use reagents is the “Orange R-net System”. The FPS recycling system

developed by Sony Corporation in Japan uses the colorless, transparent liquid from the

peels of oranges and tangerine called d-Limonene. d-Limonene is a naturally occurring

simple monoterpene found in high concentration in orange peels. It was “not

recommended” by William and Cleereman because the plastic becomes very soft and was

unusable at the end of their test.

In the Orange R-net System, FPS is crushed and simply dissolved to the

limonene. The FPS dissolves naturally upon it immersion on the orange oil. The recycled

FPS can be reprocessed to a polystyrene resin and the residual limonene oil can be used

again. They claim that the recycled FPS is of high quality.

Florida Chemical’s technical grade d-Limonene has also been found to be an

effective solvent for dissolving and compacting expanded polystyrene (EPS). Florida

Chemical employs the same approach as Sony. Large blocks of expanded polystyrene is

said to be dissolved in a matter of seconds.

Sony and Florida Chemical have shown two effective methods in recycling

different kinds of polystyrene with d-Limonene. However, problems may exist in the

Philippines to collect orange peelings to extract d-Limonene from its oil. Philippines

don’t have the rich resources of orange as with Japan and Florida. It would entail a great

7

funding, if d-Limonene is insisted to be used, to research on the effectivity of our local

citrus fruits like dalandan, calamansi, and dayap. Moreover, the PS used by both of these

companies are clean PS, unlike in this thesis which recycles post-consumer FPS food

ware.

Styro Solve is a blend of natural terpenes derived from oranges, grapefruits, and

limes, together with a small amount of a biodegradable ester (Naitove, 2003). The active

ingredient in this poly gel is also d-Limonene. The difference of this technology with the

d-Limonene recycling systems of Sony and Florida Chemical is that it can handle FPS

packaging contaminated with food wastes. Nevertheless, this recycling system needs a

densifying machine called the Solution Machine. Purchasing this machine suitable for

cafeterias and commercial kitchen cause $4000-5000 or $100-120 for a one-month lease.

Industrialized gelation unit costs $12,000 and up or it leases for $375/month. This may

not be beneficial if it will be used in the Philippines.

University of Missouri-Rolla (UMR) has devised another way to recycle PS. The

patent no.6334713 was awarded to UMR’s researchers for the process that dissolves PS

with acid methyl esters from soybean oil. This process can reduce a cubic yard of

polystyrene foam to about a quart and a half of liquid. The recycled product is useful for

making products to clean and coat metal walls and as a binding agent in road or plastics

manufacturing.

In this thesis, used coconut oil is utilized. Coconut oil, is classified as “good” at

25 ºC and “fair” at 50 ºC. Reagents categorized as “good” produce a slight clouding or

crazing of the plastic or slight coloring of the reagent. A “fair” reagent provides a visible

effect on the plastic and/or reagent. Some dimensional change is possible or weight loss

8

or gain. The deformation at higher temperatures of used oil in this thesis is expected

because of this study.

ITDI develops new ways in recycling FPS with the employment of used oils. One

of their projects is to recycle FPS with used motor oil. The motor oil is heated from 180-

240°C and the FPS is loaded into a fabricated melting unit (FMU). The product is a black

sold that can only be used as a source of fuel.

Mechanical Properties of Wood

Wood is naturally a very durable substance. It is widely employed for furniture,

floors, paper manufacture, and innumerable other purposes. Table 2.1 shows the

mechanical properties of some commercially important woods.

Common species names

Modulus of Rupture (kPa)

Compression Parallel to Grain

(kPa)

Compression Perpendicular to

Grain (kPa)

Alder, red 45,000 20,400 1,700

Beech 59,000 24,500 3,700

Cherry, black 55,000 24,400 2,500

Chestnut 39,000 17,000 2,100

Cottonwood, black 34,000 15,200 1,100

Cottonwood, Eastern 37,000 15,700 1,400

Hackberry 45,000 18,300 2,800

Table 2.1. Mechanical properties of some commercially important wood

ITDI already made recycled FPS food ware as chairs and tables, however, the

mechanical properties of this product has not been tested. In this thesis, the recycled

product will be tested of its mechanical properties and assess if it can be used as a wood

substitute.

9

Chapter 3

MECHANICAL EVALUATION OF RECYCLED POST-CONSUMER FOAMED

POLYSTYRENE FOOD WARE AS A WOOD SUBSTITUTE

ABSTRACT

The numerous advantages of foamed polystyrene (FPS) food ware over other food service wares increase its demand in food packaging services. The large demand for these products resulted to an accumulation of about 4-5 tons per day of post-consumer waste FPS in Metro Manila. The product made from recycling waste FPS in used oil is a probable wood substitute. This thesis aims to evaluate the mechanical properties of the recycled FPS as a wood substitute and to determine the waste FPS to oil ratio that would produce the strongest recycled product. Varying proportions of waste FPS were melted at temperatures of 160, 170, 180, 190, or 200 ºC. The resulting products were evaluated of their compressive strength, modulus of rupture, and hardness. The ratio of 3 parts waste FPS to 1 part used oil yields the strongest product. The compressive strength and the modulus of rupture are increasing with temperature. For both of these tests, the 3:1 ratio tolerates the greater load. The hardness of the materials have hardness ranging from 4-5 or equivalent hardness of fluorite or apatite.

INTRODUCTION

The first Earth Day, which occurred in 1970, signaled the development of a new

level of awareness and concern about the environment (Richardson, 1997). Since then

numerous efforts are being pursued to help minimize, if not eradicate, non-earth friendly

activities. The anti-litter campaigns during the 1970s, the Resources Conservation and

Recovery Act (RCRA) passed by the federal government in 1976 which promotes reuse,

reduction, incineration of materials, and several groups and alliances were formed to save

used or waste materials for reprocessing into something useful, generally known as

recycling.

Polystyrene (PS) is the most recycled form of single-service food packaging

(PSPC, 1996). Fast food chains in Metro Manila like Jollibee, McDonald’s, Wendy’s,

10

and Chowking, use foamed polystyrene (FPS) for food packaging. Its numerous

advantages over other food service wares – low cost, free of odor and taste, excellent

thermal insulator, chemically inert, good dimensional stability and rigidity, and low

moisture absorption – increase its demand in food packaging services. However, the large

demand for these products resulted to an accumulation of waste FPS in dumpsites. In

particular, about 4-5 tons per day of post-consumer waste styropacks are being generated

in Metro Manila (M. Navarro, 2004). The non biodegradability of the waste FPS poses

an additional problem to its increasing volume. It does not break down, it clogs

drainages, and it stays in landfills for a long time which causes serious environmental

problems.

Because of the issues in recycling PS food packaging wastes, several recycling

programs are being studied and implemented to reduce these PS wastes that will be

economically sustainable. According to Raymond Ehrlich, Director of Environment,

Health and Safety for the Polystyrene Packaging Council, in about 10 years, total

polystyrene recycled essentially grew from zero pounds per year to approximately 50

million pounds per year.

In the Philippines, an FPS recycling plant was set up in 1995 in Sta. Maria,

Bulacan by the Polystyrene Packaging Council of the Philippines, Inc. (PPCP) to help

minimize FPS wastes. Its collection of FPS wastes has extended to schools within the

area. One of the problems that occurred in this program is the high transportation cost of

the pick-up and delivery of the wastes to the recycling plant. This made FPS recycling

unattractive.

11

The Industrial Technology Development Institute (ITDI) under the Department of

Science and Technology (DOST) helps in discovering innovations in FPS recycling.

“Melting of Waste FPS in Used Oil” is a project of ITDI that was pursued in

collaboration with PPCP. The project aims to develop suitable processing/recycling

techniques in order to convert post-consumer waste FPS into value added functional

products (M. Navarro, 2004). The recycled product is found to be a potential substitute

for wood. ITDI has already made chairs and tables out of this technology. Yet there is a

lack of information in the waste FPS to oil ratio and the heating temperature that would

produce the strongest recycled product.

This thesis aims to evaluate the mechanical properties of the recycled FPS and

determine the waste FPS and determine the waste FPS to oil ratio that would produce the

strongest recycled product.

This thesis will help in the reduction of waste FPS and frying oil in the

environment. It will benefit the FPS producers, food chain owners, the community and

the government.

The focus of this thesis is in the evaluation of the mechanical properties of

recycled FPS. The resistance to weathering exposure and the mechanism of the reaction

of used frying oil with the FPS is no longer assessed.

METHODOLOGY

Preparation of the Sample

Post-consumer FPS food wares were taken from the storage area of ITDI. This

FPS wastes were brought to ITDI by fast food chains like Jollibee, McDonald’s,

12

Wendy’s, and Chowking. Waste FPS from Jollibee is the most abundant, so this is taken

as the sample.

Used cooking oil has been used for frying chicken in Jollibee (Figure 3.1). The

oil has been placed in a drum and all of the solids were already suspended at the bottom.

Figure 3.1 Used cooking oil

A fabricated melting unit (FMU) was provided by the ITDI. The FMU is where

the waste FPS were melted. An electric stove generates the heat in the recycling process.

A metal thermometer was used to measure the temperature of the melted waste FPS.

Steel molders of size 45 mm x 45 mm x 150 mm were also provided by the ITDI for the

recycled FPS.

250 grams of used cooking oil and 500 grams of waste FPS for 2:1 ratio or 750

grams for 3:1 ratio were weighed. Waste FPS were crushed to smaller pieces to fit the

FMU provided by the ITDI (Figure 3.2).

Figure 3.2. Crushed waste FPS

13

Used cooking oil was heated in an electric stove to 150 ºC before waste FPS is

loaded into the FMU. This temperature is based on the melt temperature of polystyrene.

The waste FPS were continuously charged to the FMU on a medium heat. Once all the

waste FPS had melted, a metal thermometer was placed on the mixture. The mixture was

heated until it had reached its desired temperature of 160, 170, 180, 190, or 200 ºC. The

melted FPS was transferred immediately to steel molders. The melted FPS is allowed to

cool and harden for about an hour. Recycled FPS products were cut to various sizes for

testing (Figure 3.3).

Figure 3.3. Cutting of recycled FPS

Hardness Test

Hardness tests were executed in ITDI. A Standard Moh’s Scale is used to test the

materials. The various standards were scratched to the sample until a dent was visible.

Compressive Strength Test

Compressive strength tests were performed in the Mechanical Engineering

Laboratory of Mapúa Institute of Technology. A Shimadzu Universal Testing Machine

(Figure 3.4) was used to test the samples. The contact area of the samples with the

machine ranges from 25-26mm x 39-40mm.

14

Figure 3.4. Shimadzu Universal Testing Machine

Modulus of Rupture Test

Modulus of rupture tests were carried out in ITDI. A Universal Testing Machine

(Figure 3.5) was used to test the samples. The samples tested have dimensions of 25 mm

x 40 mm x 150 mm.

Figure 3.5. Universal Testing Machine

15

RESULTS AND DISCUSSION

Melting of Waste FPS

Melting of FPS corresponds to the transformation of this solid material to a

viscous liquid. At 150 ºC the waste FPS starts to melt because it already has exceeded its

melting temperature. The high temperature of the used cooking oil causes the air inside

the cell to vaporize and the steam produced by the oil to diffuse inside the cells. As the

temperature is increased, more gas accumulates into the cells and builds up pressure. The

thin walls of the cell cannot withstand the pressure and eventually, the bead collapses.

This causes the deflated beads to fuse together and eventually become a viscous liquid.

Hardness Test

Hardness is a measure of a material’s resistance to localize plastic deformation.

Moh’s Hardness Scale is a qualitative hardness indexing scheme. From this test, it shows

that the products have hardness ranging from 4-5 or equivalent hardness of fluorite or

apatite.

Compressive Strength Test

Compressive strength test was used to evaluate the behavior of FPS under large

and permanent stress. In Figure 3.6, the maximum strengths of both formulations

increased as the temperature is increased. This is explained by the viscosity of the

resulting melted FPS. At higher temperatures, the melted FPS is less viscous. This lower

viscosity allows the mixture to arrange itself in order and occupy the whole molder.

There are lesser voids in the higher temperature products than those cooked at low

temperatures.

16

The 3:1 ratio shows a higher tolerance to stress. Used oil acts as the lubricant in

this recycling process. Since the 2:1 ratio is more lubricated than the 3:1, it is easier for

the load to compress the recycled product.

COMPARISON OF MAXIMUM STRESS

0

5000

10000

15000

20000

25000

30000

150 160 170 180 190 200 210

Temp (deg C)

Ma

x S

tre

ss

(k

Pa

) 2:1

3:1

Figure 3.6. Comparison of maximum stress of 2:1 and 3:1 ratio vs. temperature

Temperature 2:1 Max Stress (kPa) 3:1 Max Stress (kPa)

160 9370 10780

170 12490 14230

180 18970 21020

190 19090 22350

200 19440 23870

Table 3.1. Maximum stress of 2:1 and 3:1

Modulus of Rupture Test

The modulus of rupture test is conducted to the material to the point of failure.

The 3:1 ratio at 200 °C is the sample that carries the heavier load before fracture.

Viscosity, like the compressive strength test, is the primary reason for this trend.

17

COMPARISON OF MODULUS OF RUPTURE

0

200

400

600

800

1000

1200

1400

1600

150 160 170 180 190 200 210

Temp (deg C)

MO

R (

kP

a)

2:1

3:1

Figure 3.7. Comparison of modulus of rupture of 2:1 and 3:1 ratio vs.

temperature

Temperature 2:1 MOR (kPa) 3:1 MOR (kPa)

160 657.636435 966.3574242

170 803.576658 1108.432001

180 870.0902931 1200.236846

190 917.0905029 1351.962775

200 1016.271444 1300.856052

Table 3.2. Modulus of Rupture of 2:1 and 3:1

CONCLUSION

The ratio of 3 parts waste FPS to 1 part used oil yields the strongest product. The

mechanical evaluation of the recycled FPS food ware shows that the compressive

strength and the modulus of rupture are increasing with temperature. For both of these

tests, the 3:1 ratio tolerates the greater load. The hardness of the recycled products does

not depend on the temperature of the used oil. They have hardness ranging from 4-5 or

equivalent hardness of fluorite or apatite. In comparison of the recycled FPS with wood,

18

the recycled product can deal with as much compression as the wood, however it will

easily break. Thus, recycled FPS can be a wood substitute for short time use only.

RECOMMENDATION

It is recommended that reinforcements should be added to the recycled FPS to

enhance its mechanical properties. These reinforcements may be waste materials such as

foil packs, polyethylene cups, or other kinds of plastics.

The resistance to weathering exposure and the mechanism of the reaction of used

frying oil with the FPS should be assessed as a continuation of this study.

REFERENCES

Brydson, J.A. (1975). Plastics Materials (3rd ed.). London, England: Butterworth

& Co. Ltd. Callister, W.D. (2000). Materials Science and Engineering An Introduction (5th

ed.). Philippines: John Wiley & Sons, Inc. Ehrlich, R. J. (2004). The Economic Realities of Recycling. Arlington, Virginia:

Polystyrene Packaging Council. Mapleston, P. (August,1993). Chemical recycling to remove waste mountains...

someday. Modern Plastics International. New Jersey, USA:McGraw-Hill. Mega Packaging Corporation in Laguna, Philippines. Expandable Polystyrene

and the Environment: The Facts and the Fallacies.

Navarro, M. M. Functional Products from Waste Foamed Polystyrene. ITDI. Patton, W. J. (1976) Plastics Technology: theory, design, and manufacture.

Reston, Virginia: Reston. Richardson, T. L., & Lokensgard, E. (1997). Industrial Plastics: Theory and

Application. (3rd ed.). Albany, New York:Delmar. Williams, J.L., & Cleereman, K.J. (1952). The General Physical Properties of

Polystyrene. Styrene: Its Polymers, Copolymers, and Derivatives. New York, New York:Hafner.

19

Chapter 4

CONCLUSION

The ratio of 3 parts waste FPS to 1 part used oil yields the strongest product. The

mechanical evaluation of the recycled FPS food ware shows that the compressive

strength and the modulus of rupture are increasing with temperature. For both of these

tests, the 3:1 ratio tolerates the greater load. The hardness of the recycled products does

not depend on the temperature of the used oil. They have hardness ranging from 4-5 or

equivalent hardness of fluorite or apatite. In comparison of the recycled FPS with wood,

the recycled product can deal with as much compression as the wood, however it will

easily break. Thus, recycled FPS can be a wood substitute for short time use only.

20

Chapter 5

RECOMMENDATION

It is recommended that reinforcements should be added to the recycled FPS to

enhance its mechanical properties. These reinforcements may be waste materials such as

foil packs, polyethylene cups, or other kinds of plastics.

The resistance to weathering exposure and the mechanism of the reaction of used

frying oil with the FPS should be assessed as a continuation of this study.

21

REFERENCES

Blaga, A. Plastics. Institute for Research Construction. Brydson, J.A. (1975). Plastics Materials (3rd ed.). London, England: Butterworth

& Co. Ltd. Callister, W.D. (2000). Materials Science and Engineering An Introduction (5th

ed.). Philippines: John Wiley & Sons, Inc. Ehrlich, R. J. (2004). The Economic Realities of Recycling. Arlington, Virginia:

Polystyrene Packaging Council. Global alliance to promote recycling of expanded PS. Modern Plastics

International. New Jersey, USA:McGraw-Hill. Green, D.W., Winandy, J.E., Kretschmann, D.E. (1999). Mechanical Properties

of Wood. Madison, WI: U.S. Department of Agriculture, Forest Service,Forest Products Laboratory.

Leedy, P. D., & Ormrod, J. E. (2001). Practical Research (7th ed.). Upper Saddle

River, New Jersey:Prentice-Hall. Mapleston, P. (August,1993). Chemical recycling to remove waste mountains...

someday. Modern Plastics International. New Jersey, USA:McGraw-Hill. Mega Packaging Corporation in Laguna, Philippines. Expandable Polystyrene

and the Environment: The Facts and the Fallacies.

Miller, M. V. (1973) Plastics Technology. USA: McGraw-Hill. Navarro, M. M. Functional Products from Waste Foamed Polystyrene. ITDI. Patton, W. J. (1976) Plastics Technology: theory, design, and manufacture.

Reston, Virginia: Reston. Polystyrene Packaging Council in Washington, DC, USA(1996). Polystyrene and

Its Raw Material Styrene (A White Paper). (Rev. ed.). Richardson, T. L., & Lokensgard, E. (1997). Industrial Plastics: Theory and

Application. (3rd ed.). Albany, New York:Delmar. Sony Corporation. HKPC and Sony Introduce the “Limonene Recycling System”

to Dissolve and Recycle Polystyrene. Sony Press Release:November 30, 2001.

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University of Missouri-Rolla. Researchers Use Soybean Oil to Dissolve Foam. University of Missouri-Rolla Press Release: January 30,2002.

Williams, J.L., & Cleereman, K.J. (1952). The General Physical Properties of

Polystyrene. Styrene: Its Polymers, Copolymers, and Derivatives. New York, New York:Hafner.