ACKNOWLEDGEMENTS: Work has been supported by the National Science Foundation Research Center for Bio-renewable

Chemicals Award No. EEC-0813570 (PI Shanks) Iowa State University and the Bio-economy Institute at ISU.

Further acknowledgement of the members of the Kessler Research Group and the support of Dr. Adah Lesham and Diana

Loutsch.

Characterization of Novel Bio-based

Polyhydroxyalkanoate/Lignocellulose

Composites

Tim Jobes1, Kunwei Liu2, Samy Madbouly2, Michael Kessler2 1Lincoln High School, DMPS 2 Materials, Science & Engineering Department, ISU

RESEARCH OBJECTIVES

CRITICAL QUESTIONS CONCLUSIONS

MATERIALS

Develop New Bio-based Composites

from MirelTM & Lignin

• A biopolymer resin that shares physical properties of petroleum-based

resins, allowing processing on existing equipment with similar production

methods.

• Holds unique biodegradability properties as they are created through a

patented fermentation process and plant-derived sugar; MirelTM is certified

to biodegrade in soil and water environments.

• The first commercial scale production plant has been built adjacent to the

Archer Daniels Midland Company’s wet-corn facility in Clinton.

The MirelTM production facility in

Clinton, Iowa is designed to produce

up to 50,000,000 Kg of MirelTM

annually.

Lignin • The second most plentiful natural

polymer in the world surpassed only by

cellulose.

• Considering all polymers found within

plant cell walls, it is the only one NOT

composed of carbohydrate (sugar)

monomers.

• Global production of Lignin is estimated

at over 1 million tons per year.

RESULTS

S SAMPLE PREPARATION

MirelTM Lignin

P1003 20%

P1004 20%

P1008 20%

P4010 20%

Four different types of PHA MirelTM were mixed with 20

wt.% lignocellulose to determine which had the most

promising mechanical properties. MirelTM Lignin

P1008 0%

P1008 1%

P1008 5%

P1008 10%

P1008 20%

P1008 30%

P1008 40%

PHA MirelTM 1008 was selected for further study and

evaluation. Blends were extruded ranging from pure

MirelTM to 40% Lignin. The production process in

preparing blends was heated to a consistent

temperature of 185 oC.

• Is it possible to create a bio-based composite from

these two materials that would significantly reduce

material costs while maintaining critical material

properties for successful fabrication and consumer

use?

• Considering current production practices for injection

molding, which polyhydroxyalkanoate to lignocellulose

ratio will produce the best material for proposed

applications?

• Novel bio-based polyhydroxyalkanoate/lignocellulose polymer

composites with different concentrations of lignocellulose were

successfully prepared using the twin-screw extruder at 185 ºC

with a rotation speed of 100 rpm.

• Characterization of the polymer composites was performed using

DMA, DSC and TGA.

• The concentrations of lignocellulose have little effect on the glass

transition temperature of the resulting blends.

• The melting points of the composites were depressed as the

concentration of the lignocellulose increases. The crystallization

points of the blends systematically shift to lower temperature as

the concentration of the lignocellulose increases.

MirelTM was blended with different percentages of lignin using a twin-

screw micro compounder; temperature and turning speed maintained

by a computerized control module.

Twin-screw Micro Compounder

Computerized Control Module

Temperature was maintained at 185o C at 100 RPM

Aluminum alloy forms were

created for compression molded

production at the prescribed

temperature and pressure.

Molded material was specifically

designed to facilitate DMA testing

Aluminum Form Heat and Pressure

Controlled Molding

Properties of the polymer blends were analyzed

using the following Techniques:

• Dynamical mechanical analysis (DMA)

• Differential scanning calorimetric (DSC)

• Thermal gravimetric analysis (TGA)

Fig. 1 Weight percent as a function of temperature for PHA/lignin

blends of different concentrations at a heating rate of 20 oC/min. The

inset-plot focuses on the data at the temperature range of 200-350 ºC.

Fig. 2 DSC thermograms for the crystallization process of for PHA/lignin

blends of different concentrations at a cooling rate of 20 º C/min.

Fig. 4 Dynamic storage modulus, E’, as a function of temperature for

PHA/lignin blends of different concentrations at a frequency of 1 Hz and 3º

C/min heating rate.

Fig. 5 Tan d as a function of temperature for PHA/lignin blends of different

concentrations at a frequency of 1 Hz and 3o C/min heating rate.

Fig. 3 Development of melting point at different concentrations.

The DSC were carried out at 20oC/min heating rate (Second heating run).

CHARACTERIZATION