Browsing by Author "Khater, Ali Zein"

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    Epoxy compositions containing polyrotaxane additives having improved impact strength
    (2025-02-25) Patel, Hasmukh A.; Khater, Ali Zein; Boul, Peter; Ajayan, Pulickel M.; Rahman, Muhammad M.; Rice University; Saudi Arabian Oil Company; United States Patent and Trademark Office
    This document relates to epoxy compositions containing a sliding-ring polymer (polyrotaxane) additive and a thermally-curable epoxy resin. The epoxy compositions exhibit increased flexural toughness and impact resistance as compared to the same epoxy composition that does not contain the additive. This document also relates to 3D-printed epoxy compositions containing a sliding-ring polymer (polyrotaxane) additive and a thermally-curable epoxy resin.
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    Fabrication and Characterization of Advanced Epoxy-based Composites and Nanocomposites
    (2023-08-08) Khater, Ali Zein; Ajayan, Pulickel M; Rahman, Muhammad M
    We live in the age of development. The age of new technology. Of automated manufacturing and processing. Transportation is breaking new limits, passing the boundaries of the sky towards the heavens. Soon, travel across the world in minutes will become a reality with hypersonic travel. Automated and self-driving vehicles might one day be a relied means of transportation. With these advancements in technology, a new era of materials and manufacturing are necessary. Advanced materials must be developed that can reduce weight, reduce production and manufacturing time, respond intelligently or with design and intent, and reduce waste to thrust aviation, automotives, energy, technologies, and automation of technologies into this age of automation dubbed the fourth industrial revolution (IR4.0). Herein, this thesis discusses the development and testing of epoxy composites showing how additive manufacturing (AM) can be used to better process carbon nanotubes (CNTs), how the shape memory properties of epoxy can be tuned using polyrotaxane (PR), and impact tolerance of a PR epoxy. From these efforts, it has been shown that AM facilitates the processing of CNTs thus improving the processing dynamics of CNTs in epoxy in comparison to the mold cast counterpart via void reduction and CNT dispersion, wetting, and partial alignment. Likewise, this work shows that the addition of PR to a shape memory epoxy improves the strain to failure and improves shape recovery time with increased PR loading. Lastly, the effects of PR on epoxy are investigated to show how the addition of PR affects the impact resistance under repeated low velocity impacts of incrementally increasing energies. These collective works are united by the demand for advanced materials and manufacturing developments in IR4.0 where polymers provide lightweight and mechanically robust alternatives to heavy and dense metal components. Thus, this thesis will add to the body of literature and understanding necessary to continue growing the field of materials engineering and science.
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    Sustainable valorization of asphaltenes via flash joule heating
    (AAAS, 2022) Saadi, M.A.S.R.; Advincula, Paul A.; Thakur, Md Shajedul Hoque; Khater, Ali Zein; Saad, Shabab; Shayesteh Zeraati, Ali; Nabil, Shariful Kibria; Zinke, Aasha; Roy, Soumyabrata; Lou, Minghe; Bheemasetti, Sravani N.; Bari, Md Abdullah Al; Zheng, Yiwen; Beckham, Jacob L.; Gadhamshetty, Venkataramana; Vashisth, Aniruddh; Kibria, Md Golam; Tour, James M.; Ajayan, Pulickel M.; Rahman, Muhammad M.
    The refining process of petroleum crude oil generates asphaltenes, which poses complicated problems during the production of cleaner fuels. Following refining, asphaltenes are typically combusted for reuse as fuel or discarded into tailing ponds and landfills, leading to economic and environmental disruption. Here, we show that low-value asphaltenes can be converted into a high-value carbon allotrope, asphaltene-derived flash graphene (AFG), via the flash joule heating (FJH) process. After successful conversion, we develop nanocomposites by dispersing AFG into a polymer effectively, which have superior mechanical, thermal, and corrosion-resistant properties compared to the bare polymer. In addition, the life cycle and technoeconomic analysis show that the FJH process leads to reduced environmental impact compared to the traditional processing of asphaltene and lower production cost compared to other FJH precursors. Thus, our work suggests an alternative pathway to the existing asphaltene processing that directs toward a higher value stream while sequestering downstream emissions from the processing.