We have investigated the dynamics of a reaction coordinate with or without coupling to a heat bat... more We have investigated the dynamics of a reaction coordinate with or without coupling to a heat bath of harmonic oscillators using a novel time-dependent discrete variable representation (TDDVR) method. The proposed method is semiclassical in nature, theoretically rigorous, and rather straightforward to implement. Excellent agreement of the computed tunneling probabilities and time-averaged tunneling rates with the corresponding exact results demonstrates the efficacy of the proposed approach. Most of the semiclassical calculations reported here have been performed by using classical force, whereas, in a few cases, the quantum force (QF) has been taken into account. It appears that among the TDDVR formulations, it was the first time we have derived a rigorous form of QF from the first principle.
Abstract A novel class of polystyrene-based gel-type resins (SPACeR, SP), containing the large 1,... more Abstract A novel class of polystyrene-based gel-type resins (SPACeR, SP), containing the large 1,4-bis(4-vinylphenoxy)benzene cross-linker, is introduced; SP-immobilized 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) and triethylamine (TEA) bases are synthesized and characterized in terms of their structural, thermal and morphological features, and their catalytic efficiency in a series of fundamental chemical transformations under solvent-free conditions is investigated.
Various high energetic materials (HEMs) like RDX and HMX are crystalline solids that are sensitiv... more Various high energetic materials (HEMs) like RDX and HMX are crystalline solids that are sensitive to shock. Suitable fluorinated polymeric binders will be a potential replacement to the conventional stable but un-energetic hydroxyl-terminated polybutadiene (HTPB) for processing them in a shock insensitive and machinable form without decreasing the overall energy. Synthesis of fluorosubstituted epoxy monomer followed by synthesis of the corresponding fluorinated polymeric binder via cationic ring-opening polymerization is discussed in this paper.
We present how altering the chain flexibility affects the nanoscale organization of polymer‐graft... more We present how altering the chain flexibility affects the nanoscale organization of polymer‐grafted nanoparticles (PGNPs) and its ultimate impact on macroscale thermal properties. To isolate the role of chain flexibility on wetting behavior in athermal polymer nanocomposites (PNC), the graft and matrix chemistry is kept identical by utilizing 1,3‐cyclohexadiene‐based polymer materials. Increasing the rigidity and molecular weight of both the graft and matrix is found to favor mixing of poly(1,3‐cyclohexadiene) PCHD‐grafted silica NPs with the matrix, supported by a concomitant increase in glass transition temperatures of the PNCs. Further, the associated entropic factors that drive wetting behavior and dispersion of PGNPs are discussed, emphasizing the dominant role‐played by chain flexibility. Alterations in graft flexibility had the strongest impact on dispersion and Tg values of the PNC, while molecular weight (MW) plays a secondary role. This investigation is a unique demonstrat...
Abstract A novel class of polystyrene-based gel-type resins (SPACeR, SP), containing the large 1,... more Abstract A novel class of polystyrene-based gel-type resins (SPACeR, SP), containing the large 1,4-bis(4-vinylphenoxy)benzene cross-linker, is introduced; SP-immobilized 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) and triethylamine (TEA) bases are synthesized and characterized in terms of their structural, thermal and morphological features, and their catalytic efficiency in a series of fundamental chemical transformations under solvent-free conditions is investigated.
Flexible polymer (polyvinyl alcohol, PVA) nanofibres achieved with electrospinning and loaded wit... more Flexible polymer (polyvinyl alcohol, PVA) nanofibres achieved with electrospinning and loaded with picosecond laser-ablated gold nanoparticles (Au NPs) were utilized as surface-enhanced Raman scattering (SERS) substrates. The fabricated polymer nanofibres and Au NPs were characterized by UV–Visible absorption, field emission scanning electron microscope, transmission electron microscopy and X-ray diffraction techniques. The PVA–Au NPs SERS substrates were used to detect the dye methylene blue (MB 5 µM) and a chemical warfare agent simulant (methyl salicylate) using a portable Raman spectrometer. The flexible PVA–Au NPs nanofibre exhibited a good sensitivity with enhancement factors of >104 and a high reproducibility (RSD ~10%). These flexible substrates could be extended for SERS studies of various explosive and other hazardous molecules.
Various high energetic materials (HEMs) like RDX and HMX are crystalline solids that are sensitiv... more Various high energetic materials (HEMs) like RDX and HMX are crystalline solids that are sensitive to shock. Suitable fluoro-nitro polymeric binders will be a potential replacement to the conventional stable but un-energetic hydroxyl-terminated polybutadiene (HTPB) for processing them in a shock insensitive and machinable form without decreasing the overall energy. Synthesis of fluoro-and nitro-substituted epoxy monomers followed by synthesis of the corresponding fluoro/fluoro-nitro polymeric binders via cationic ring-opening polymerization are discussed in this paper. Keywords-component; Energetic Materials; Binders; Fluorinated Polymers; Nitro Polymers
We have investigated the dynamics of a reaction coordinate with or without coupling to a heat bat... more We have investigated the dynamics of a reaction coordinate with or without coupling to a heat bath of harmonic oscillators using a novel time-dependent discrete variable representation (TDDVR) method. The proposed method is semiclassical in nature, theoretically rigorous, and rather straightforward to implement. Excellent agreement of the computed tunneling probabilities and time-averaged tunneling rates with the corresponding exact results demonstrates the efficacy of the proposed approach. Most of the semiclassical calculations reported here have been performed by using classical force, whereas, in a few cases, the quantum force (QF) has been taken into account. It appears that among the TDDVR formulations, it was the first time we have derived a rigorous form of QF from the first principle.
Abstract A novel class of polystyrene-based gel-type resins (SPACeR, SP), containing the large 1,... more Abstract A novel class of polystyrene-based gel-type resins (SPACeR, SP), containing the large 1,4-bis(4-vinylphenoxy)benzene cross-linker, is introduced; SP-immobilized 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) and triethylamine (TEA) bases are synthesized and characterized in terms of their structural, thermal and morphological features, and their catalytic efficiency in a series of fundamental chemical transformations under solvent-free conditions is investigated.
Various high energetic materials (HEMs) like RDX and HMX are crystalline solids that are sensitiv... more Various high energetic materials (HEMs) like RDX and HMX are crystalline solids that are sensitive to shock. Suitable fluorinated polymeric binders will be a potential replacement to the conventional stable but un-energetic hydroxyl-terminated polybutadiene (HTPB) for processing them in a shock insensitive and machinable form without decreasing the overall energy. Synthesis of fluorosubstituted epoxy monomer followed by synthesis of the corresponding fluorinated polymeric binder via cationic ring-opening polymerization is discussed in this paper.
We present how altering the chain flexibility affects the nanoscale organization of polymer‐graft... more We present how altering the chain flexibility affects the nanoscale organization of polymer‐grafted nanoparticles (PGNPs) and its ultimate impact on macroscale thermal properties. To isolate the role of chain flexibility on wetting behavior in athermal polymer nanocomposites (PNC), the graft and matrix chemistry is kept identical by utilizing 1,3‐cyclohexadiene‐based polymer materials. Increasing the rigidity and molecular weight of both the graft and matrix is found to favor mixing of poly(1,3‐cyclohexadiene) PCHD‐grafted silica NPs with the matrix, supported by a concomitant increase in glass transition temperatures of the PNCs. Further, the associated entropic factors that drive wetting behavior and dispersion of PGNPs are discussed, emphasizing the dominant role‐played by chain flexibility. Alterations in graft flexibility had the strongest impact on dispersion and Tg values of the PNC, while molecular weight (MW) plays a secondary role. This investigation is a unique demonstrat...
Abstract A novel class of polystyrene-based gel-type resins (SPACeR, SP), containing the large 1,... more Abstract A novel class of polystyrene-based gel-type resins (SPACeR, SP), containing the large 1,4-bis(4-vinylphenoxy)benzene cross-linker, is introduced; SP-immobilized 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) and triethylamine (TEA) bases are synthesized and characterized in terms of their structural, thermal and morphological features, and their catalytic efficiency in a series of fundamental chemical transformations under solvent-free conditions is investigated.
Flexible polymer (polyvinyl alcohol, PVA) nanofibres achieved with electrospinning and loaded wit... more Flexible polymer (polyvinyl alcohol, PVA) nanofibres achieved with electrospinning and loaded with picosecond laser-ablated gold nanoparticles (Au NPs) were utilized as surface-enhanced Raman scattering (SERS) substrates. The fabricated polymer nanofibres and Au NPs were characterized by UV–Visible absorption, field emission scanning electron microscope, transmission electron microscopy and X-ray diffraction techniques. The PVA–Au NPs SERS substrates were used to detect the dye methylene blue (MB 5 µM) and a chemical warfare agent simulant (methyl salicylate) using a portable Raman spectrometer. The flexible PVA–Au NPs nanofibre exhibited a good sensitivity with enhancement factors of >104 and a high reproducibility (RSD ~10%). These flexible substrates could be extended for SERS studies of various explosive and other hazardous molecules.
Various high energetic materials (HEMs) like RDX and HMX are crystalline solids that are sensitiv... more Various high energetic materials (HEMs) like RDX and HMX are crystalline solids that are sensitive to shock. Suitable fluoro-nitro polymeric binders will be a potential replacement to the conventional stable but un-energetic hydroxyl-terminated polybutadiene (HTPB) for processing them in a shock insensitive and machinable form without decreasing the overall energy. Synthesis of fluoro-and nitro-substituted epoxy monomers followed by synthesis of the corresponding fluoro/fluoro-nitro polymeric binders via cationic ring-opening polymerization are discussed in this paper. Keywords-component; Energetic Materials; Binders; Fluorinated Polymers; Nitro Polymers
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