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Towards Development of Lignin Reinforced Elastomeric Compounds with Reduced Energy Dissipation

Bahl, Kushal
http://rave.ohiolink.edu/etdc/view?acc_num=akron1397055385

Abstract Details

2014, Doctor of Philosophy, University of Akron, Polymer Engineering.
This research deals with development of lignin as reinforcing filler for elastomeric compounds. Lignins are naturally abundant and cost competitive wood derivatives possessing strong mechanical properties and offering reactive functional groups on their surfaces. The presence of the functional groups imparts polarity to the lignin molecules and makes them incompatible with non-polar elastomers. Also, the large particle size of lignin does not produce desired mechanical reinforcement. The present study deals with solving the outstanding issues associated with the use of lignin as fillers for polymeric compounds. In addition, the work specifically focuses on producing rubber compounds with reduced energy dissipation via partial replacement of carbon black with lignin. The first part of this study is devoted to suppression of the polarity of lignin and achievement of compatibility with rubber matrix via modification of lignosulfonates (LS) with cyclohexylamine (CA). CA reduces the polarity of lignin via interactions originating from proton transfer and hydrogen bonding. X-ray Photoelectron Spectroscopy (XPS) confirms the attachment of CA on the surfaces of lignin. The mechanical properties of rubber compounds increase substantially along with improvement in cure properties and increase in crosslink density in the presence of LS particles modified with CA. The tensile strength and storage modulus show an increase by 45% and 41% respectively. The values of the 100% modulus and elongation at break also improve by 35% and 60% respectively. The second part of this study exploits the non-covalent interactions between lignin and carbon black (CB) for the design of novel hybrid filler particles exhibiting lower energy loss in rubber compounds. The hybrid fillers offer unique morphology consisting of coating layers of lignin on carbon black particle aggregates. It is found that such coating layers are formed due to p-p interactions between lignin and carbon black. Raman spectroscopy and 1H spin-lattice relaxation times confirm p-p interactions. The hybrid fillers offer reduction of networking of carbon black particles and viscoelastic dissipation in rubber compounds without sacrificing the mechanical performance. The third part of this study evaluates the performance of polybutadiene-g-polypentafluorostyrene (PB-g-PPFS) as a coupling agent for promotion of interactions between lignin and rubber and to achieve better overall reinforcing performance. The PB domains of PB-g-PPFS are compatible with styrene-butadiene rubber (SBR) while the PPFS segments engage in arene-perfluoroarene interactions with lignin. These interactions are confirmed via UV-vis spectroscopy data. The efficacy of PB-g-PPFS as a coupling agent is evaluated for compounds filled with lignin and lignin/carbon black hybrid fillers. The results show that the addition of PB-g-PPFS improves the tensile strength by 33% and reduces the viscoelastic loss in filled SBR compounds by improving filler dispersion. The results presented in this thesis demonstrate that the approaches of surface modification, exploitation of non-covalent interactions, and the use of coupling agents are effective in solving the impending issues associated with the use of lignin, the second most abundant bio-derived material, as effective reinforcing filler for polymer compounds.
Sadhan Jana, Dr. (Advisor)
Avraam Isayev, Dr. (Committee Member)
Alamgir Karim, Dr. (Committee Member)
Li Jia, Dr. (Committee Member)
Bi-Min Zhang Newby, Dr. (Committee Member)
199 p.
Polymers

Recommended Citations

Citations

  • Bahl, K. (2014). Towards Development of Lignin Reinforced Elastomeric Compounds with Reduced Energy Dissipation [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1397055385

    APA Style (7th edition)

  • Bahl, Kushal. Towards Development of Lignin Reinforced Elastomeric Compounds with Reduced Energy Dissipation. 2014. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1397055385.

    MLA Style (8th edition)

  • Bahl, Kushal. "Towards Development of Lignin Reinforced Elastomeric Compounds with Reduced Energy Dissipation." Doctoral dissertation, University of Akron, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1397055385

    Chicago Manual of Style (17th edition)

akron1397055385
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This open access ETD is published by University of Akron and OhioLINK.