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Curing Behavior and Thermomechanical Performance of Bioepoxy Resin Synthesized from Vanillyl Alcohol: Effects of the Curing Agent
No full textIn order to reduce the dependency of resin synthesis on petroleum resources, vanillyl alcohol which is a renewable material that can be produced from lignin has been used to synthesize bioepoxy resin. Although it has been widely reported that the curing reaction and properties of the cured epoxies can be greatly affected by the molecular structure of the curing agents, the exact influence remains unknown for bioepoxies. In this study, four aliphatic amines with different molecular structures and amine functionalities, namely triethylenetetramine (TETA), Tris(2-aminoethyl)amine (TREN), diethylenetriamine (DETA), and ethylenediamine (EDA), were used to cure the synthesized vanillyl alcohol-based bioepoxy resin (VE). The curing reaction of VE and the physicochemical properties, especially the thermomechanical performance of the cured bioepoxies with different amine functionalities, were systematically investigated and compared using different characterization methods, such as DSC, ATR-FTIR, TGA, DMA, and tensile testing, etc. Despite a higher curing temperature needed in the VE-TETA resin system, the cured VE-TETA epoxy showed a better chemical resistance, particularly acidic resistance, as well as a lower swelling ratio than the others. The higher thermal decomposition temperature, storage modulus, and relaxation temperature of VE-TETA epoxy indicated its superior thermal stability and thermomechanical properties. Moreover, the tensile strength of VE cured by TETA was 1.4-2.6 times higher than those of other curing systems. In conclusion, TETA was shown to be the optimum epoxy curing agent for vanillyl alcohol-based bioepoxy resin
Improvement on high rate performance of LiFePO4 cathodes using
No full textIn this work, the electrochemical properties of the LiFePO4 cathode using graphene as a conductive agent were revealed. Compared to the conventional LiFePO4 electrodes with carbon black as a conductive agent, the graphene sheets can establish a more effective conductive framework due to their layered structure and excellent electronic conductivity, leading to better electrochemical rate performance. Furthermore, the obverse of increasing graphene content is continued gains in high-rate performance of the LiFePO4 electrodes. The electrodes with 30 wt.% graphene show high capacities up to 103.1 mAh/g and 68 mAh/g during discharging with extremely high rates of 30 C and 50 C, respectively. Besides, good cycling performance at high rate is also achieved. The electrodes with 30 wt% graphene display a capacity retention higher than 80% after 1000 cycles at 30 C. These results not only indicate that the graphene could be a promising candidate as a conductive agent, but also provide a new insight for designing LiFePO4 electrodes with brilliant high-rate performance via a simple method
One-Pot Solvent-Free Synthesis of Imine-Based Epoxidized Soybean Oil Vitrimers for Sustainable Adhesives
No full textThe traditional methods for synthesizing imine based epoxidized soybean oil (ESO) vitrimers often rely on organic solvents, leading to issues such as incomplete raw material conversion, increased production costs, and environmental concerns, contradicting the principles of green and sustainable chemistry. To overcome these challenges, we propose an innovative one-pot, solvent-free approach for synthesizing imine linked ESO vitrimers via a melt reaction utilizing ESO, vanillin, and diamines. In this system, three distinct reactions can occur: phenolic hydroxy-epoxy, amino-aldehyde, and amino-epoxy. Our findings indicate that the first two reactions occur more readily and rapidly than the third, facilitating the successful synthesis of the vitrimers. We employed three different diamines to tailor the chemical structure and control properties of the ESO vitrimers; aromatic diamines produced rigid vitrimers with high strength but low ductility, while aliphatic diamines yielded flexible vitrimers with lower strength but higher ductility. All vitrimers exhibited rapid high-temperature stress relaxation and excellent reprocess ability and thermal stability. Notably, these vitrimers demonstrated impressive adhesive properties, achieving lap shear strengths between 4.0 and 6.7MPa when applied to various substrates, including wood, steel ,and aluminum . Moreover, the dynamic mine bonds enable exceptional recyclability, removability, and reusability, with recycled ESO vitrimers even surpassing their virgin counterparts in mechanical and adhesive performance, underscoring the significance of this work in advancing sustainable adhesive materials with enhanced functionality and circularity
Insight into the synthesis and thermomechanical properties of short-long type biobased aliphatic polyesters
No full textA series of biobased short-long chain aliphatic polyesters having high molecular weight were successfully synthesized using dimethyl sebacate and diols with different carbon chain lengths via a two-step melt-polycondensation method by using titanium butoxide as a catalyst. The diols chain length and its odd-even effect on the structure-property relationship, crystallinity, and thermomechanical properties of the polyesters were systemically investigated. The synthesized polyesters displayed weight-average molecular weight between 23,600 to 72,900 g/mol and a maximum intrinsic viscosity of 0.933 dL/g. With increasing the diol chain length, the molecular weight of the polyesters increased linearly, except for poly (butylene sebacate) (PBS). Altogether, the odd-even effect of the diol chain on the crystalline (Tc)/melting temperature (Tm), and melting/ crystallization enthalpies of the polyester\u27s were observed. Poly (pentylene sebacate) (PPeS) has the highest weight-average molecular weight of 72,900 Da, Tm of 55.4C, degradation temperature (Td, max) of about 404C, and highest storage modulus (E0 at 25 C) of 661 MPa compared to other short-chain polyesters. PBS and PPeS showed the appearance of sharp intensity peaks from XRD diffraction patterns, indicating higher crystallinity in the material, in accordance with crystallization enthalpies (AHc) values from the differential scanning calorimetry (DSC) thermograms. These fabricated bio-based polymers with 100% bio-content, low melting temperature range, rapid crystallization, and high thermal stability suggest good processability and can offer an alternative option to nonrenewable thermoplastic polyesters for potential applications
Improving Breast Cancer Modifiable Risk Factor Knowledge Among Patients in a High Risk Breast Cancer Prevention Clinic in the Midwest
Get PDFPreventative health care is the best choice in moving forward to reduce disease incidence. In the case of breast cancer, prevention clinics have been set up for those who have been determined as a high risk status for developing breast cancer over the course of their lifetime. There are many risk factors for breast cancer that are out of the patient’s control, but there are lifestyle health behaviors that could be implemented to lower the patient’s risk. The potential impact of these can not only lower the incidence of breast cancer, but can be linked with reduction of other disease development and help decrease the health care associated costs. Once a patient fully understands the impact that their lifestyle can have over their risk status, they can make an informed decision on whether or not the modifiable risk factors are worth implementing for them. This project measured the knowledge of breast cancer lifestyle prevention strategies among patients in a Midwest Cancer Center and evaluated how the addition of an educational intervention video on risk factors impacted the patient’s understanding. The quantitative study design analyzed pre- and post-survey participant knowledge assessment data to find that the use of the educational intervention was effective in increasing patient understanding. This project can bring awareness to all healthcare team members on the benefits of focusing on preventative healthcare, importance of checking for patient understanding on education provided to them and offering alternative avenues to increase patient knowledge
Class at Kelce, Undated
No full textBlack and white photo of students writing papers on computers, undated.https://digitalcommons.pittstate.edu/kelcebuilding/1030/thumbnail.jp
Class at Kelce, Undated
No full textBlack and white photo of a professor teaching class in Kelce. The back of the photo has one word written on it, possibly Businesshttps://digitalcommons.pittstate.edu/kelcebuilding/1039/thumbnail.jp
Front of Kelce, 1960s
No full textBlack and white photo of the entrance to the Gladys A. Kelce building, the name of the building is not on the wall. Possibly from the 1960s.https://digitalcommons.pittstate.edu/kelcebuilding/1159/thumbnail.jp
Hartman Exterior
No full textBlack and white photo of Hartman Hall. Mechanic Arts Building provides shops for Automobile Mechanics and Airplane Mechanics, and, on the second floor, classrooms and laboratories for Physics and Electricity, also the offices of the Director of Adult Education and Coordinator for Veteran Educationhttps://digitalcommons.pittstate.edu/hartmanhall/1008/thumbnail.jp
Basketball Game, Undated
No full textBlack and white photo taken during a basketball game in the gymnasium. Teams unknown, possibly taken in the 1960s or 70s.https://digitalcommons.pittstate.edu/weede_gym/1002/thumbnail.jp