Shrikant Khot

Bio: Shrikant Khot is an academic researcher from University of Delaware. The author has contributed to research in topics: Melt spinning & Epoxidized soybean oil. The author has an hindex of 7, co-authored 8 publications receiving 1083 citations.

Development and application of triglyceride‐based polymers and composites

Abstract: Triglyceride oils derived from plants have been used to synthesize several different monomers for use in structural applications. These monomers have been found to form polymers with a wide range of physical properties. They exhibit tensile moduli in the 1–2 GPa range and glass transition temperatures in the range 70–120 °C, depending on the particular monomer and the resin composition. Composite materials were manufactured utilizing these resins and produced a variety of durable and strong materials. At low glass fiber content (35 wt %), composites produced from acrylated epoxidized soybean oil by resin transfer molding displayed a tensile modulus of 5.2 GPa, a flexural modulus of 9 GPa, a tensile strength of 129 MPa, and flexural strength of 206 MPa. At higher fiber contents (50 wt %) composites produced from acrylated epoxidized soybean oil displayed tensile and compression moduli of 24.8 GPa each, and tensile and compressive strengths of 463.2 and 302.6 MPa, respectively. In addition to glass fibers, natural fibers such as flax and hemp were used. Hemp composites of 20% fiber content displayed a tensile strength of 35 MPa and a tensile modulus of 4.4 GPa. The flexural modulus was ∼2.6 GPa and the flexural strength was in the range 35.7–51.3 MPa, depending on the test conditions. The flax composite materials had tensile and flexural strengths in the ranges 20–30 and 45–65 MPa, respectively. The properties exhibited by both the natural- and synthetic fiber-reinforced composites can be combined through the production of “hybrid” composites. These materials combine the low cost of natural fibers with the high performance of synthetic fibers. Their properties lie between those displayed by the all-glass and all-natural composites. Characterization of the polymer properties also presents opportunities for improvement through genetic engineering technology. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 703–723, 2001

High modulus polymers and composites from plant oils

Abstract: The liquid resins described herein are derived from plant and animal oil triglycerides by suitably functionalizing the triglyceride with chemical groups that render it polymerizable. The triglyceride molecular structure is a combination of various triesters of fatty acids linked together with glycerol. The fatty acid residues are linear carboxylic acids containing from about 4 to about 30 carbon atoms, but preferably from about 14 to about 22 carbons and from about zero to about 4, or preferably from about 2 to 3 carbon-carbon double bonds. As obtained in nature, these double bonds are predominantly in the cis (Z) configuration and, in the case of polyunsaturated acids, not conjugated. The fatty acids derived from triglycerides include, but are not limited to the following: Lauric (C12:0), i.e., 12 carbon atoms long containing zero C=C double bonds, Myristic (C14:0), Palmitic (C16:0), Stearic (C18:0), Oleic (C18:1), Linoleic (C18:2), Linolenic (C18:3), Eicosanoic (C20:0), cis-11-Eicosanoic (C20:1), Docosanoic (C22:0) and cis-13-Docosanoic (C22:1). Typical plant oil triglycerides used for the purpose of this invention contain about 10-20 % saturated, about 20-30 % mono-unsaturated, about 40-60 % di-unsaturated, and about 5-15 % tri-unsaturated fatty acid residues, but other distributions, both narrow and broad, of fatty acid residues can also be used for the thermoset and plastic resins described in this invention.

Structure development during melt spinning and subsequent annealing of polybutene‐1 fibers

Abstract: The structural development during the melt spinning and subsequent annealing of polybutene-1 fibers was studied with in situ wide-angle X-ray scattering techniques. The online spinning apparatus consisted of a vertically translating extruder that allowed different distances from the spinneret to the stationary X-ray beam to be sampled. For all take-up speeds examined, phase II crystals mainly were formed, with only a small population of phase I crystals existing. As the take-up speed was increased, the crystallinity also increased, indicating that strain-induced crystallization prevailed. The crystalline orientations observed online were very close to perfect alignment with the fiber axis. In addition, annealing studies were performed to study aspects of the gradual phase II to phase I transformation as functions of time and prior processing take-up speed. This transformation was strongly dependent on the take-up speed. The dependence appears to be connected to local stress enhancement via chains connecting crystallites. The results also seem to indicate that at low take-up speeds (17 mpm) there is a series connectivity of amorphous and crystalline components in the fiber, whereas at greater take-up speeds (100 and 250 mpm), the morphology grows into some type of three-dimensional network, possibly a shish–kebob-type morphology. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1872–1882, 2000