Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


Final Dissertation.pdf (93.94 MB)

ETD Abstract Container

Abstract Header

A novel use of bio-based natural fibers, polymers, and rubbers for composite materials.

Modi, Sunny J.
http://rave.ohiolink.edu/etdc/view?acc_num=osu1403205265

Abstract Details

2014, Doctor of Philosophy, Ohio State University, Food Science and Technology.
The composites, materials, and packaging industries are searching for alternative materials to attain environmental sustainability. Bio-plastics are highly desired and current microbially-derived bio-plastics, such as PHA (poly-(hydroxy alkanoate)), PHB (poly-(hydroxybutyrate)), and PHBV (poly-(β-hydroxy butyrate-co-valerate)) could be engineered to have similar properties to conventional thermoplastics. Poly-(hydroxybutyrate) (PHB) is a bio-degradable aliphatic polyester that is produced by a wide range of microorganisms. Basic PHB has relatively high glass transition and melting temperatures. To improve flexibility for potential packaging applications, PHB is synthesized with various co-polymers such as Poly-(3-hydroxyvalerate) (HV) to decrease the glass and melting temperatures and, since there is improved melt stability at lower processing temperatures, broaden the processing window. However, previous work has shown that this polymer is too brittle, temperature-sensitive, and hydrophilic to meet packaging material physical requirements. Therefore, the proposed work focuses on addressing the needs for bio-derived and bio-degradable materials by creating a range of composite materials using natural fibers as reinforcement agents in bio-polymers and bio-plastic-rubber matrices. The new materials should possess properties lacking in PHBV and broaden the processing capabilities, elasticity, and improve the mechanical properties. The first approach was to create novel composites using poly-(β-hydroxy butyrate-co-valerate) (PHBV) combined with fibers from invasive plants such as common reed (Phragmites australis), reed canary grass (Phalaris arundinacea), and water celery (Vallisneria americana). The composites were manufactured using traditional processing techniques of extrusion compounding followed by injection molding of ASTM type I parts. The effects of each bio-fiber at 2, 5, and 10% loading on the mechanical, morphological, rheological, and thermal properties of PHBV were investigated. Many of the composites showed miscible blends between the fibers and PHBV. When the mechanical properties of the composites were compared to pure PHBV, the composites showed improvements in the tensile modulus, while limited changes were observed in the tensile strength and elongation at break. Also, improvements in the viscosity at 170°C over pure PHBV were observed with the addition of 10% by weight bio-fibers due to fiber-fiber and fiber-matrix interactions. With these improvements in the melt stability, the composites can be processed above the melting temperature of 165-170°C, a marked benefit over pure PHBV. The brittle nature of PHBV and its relatively high water transmission rates making it unsuitable for packaging applications. New blends of PHBV with high molecular weight natural rubber of matched viscosity were developed. The mechanical, rheological, and thermal properties of the blends with 5, 10, 15, and 25% by weight high molecular weight natural rubber (HMW-NR) were characterized; in addition, the water vapor transmission rates of these blends was determined. The results showed increased thermal stability and more uniform melting peaks for the blends compared to pure PHBV. The water permeation decreased with the addition of HMW-NR, and the permeation rates were similar to that of traditional thermoplastics. The addition of rubber increased the elongation at break without adversely affecting the Young’s modulus for the blends. The complex viscosity of the blends was improved by one log over pure PHBV at 170°C suggesting improved thermal stability of the blends. During creep and recovery testing, higher compliance values of the blends suggest increased entanglements network of PHBV and rubber micro-fibrils preventing the blends from developing permanent deformation. Therefore, these blends can potentially be used in-place of transitional thermoplastics in casting sheets and thermoforming.
Yael Vodovotz (Advisor)
Jose Castro (Committee Member)
Katrina Cornish (Committee Member)
Kurt Koelling (Committee Member)
136 p.
Food Science; Packaging; Plastics; Polymer Chemistry; Polymers

Recommended Citations

Citations

  • Modi, S. J. (2014). A novel use of bio-based natural fibers, polymers, and rubbers for composite materials. [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1403205265

    APA Style (7th edition)

  • Modi, Sunny. A novel use of bio-based natural fibers, polymers, and rubbers for composite materials. 2014. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1403205265.

    MLA Style (8th edition)

  • Modi, Sunny. "A novel use of bio-based natural fibers, polymers, and rubbers for composite materials." Doctoral dissertation, Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1403205265

    Chicago Manual of Style (17th edition)

osu1403205265
485
© 2014, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.