Showing papers by "Suat Hong Goh published in 2002"
TL;DR: In this paper, multi-walled carbon nanotubes (MWNTs) were sonicated in the dimethylformamide solution of poly(vinylidene fluoride) (PVDF), and the PVDF-covered MWNTs were then melt-blended with poly(methyl methacrylate) (PMMA).
175 citations
TL;DR: In this paper, the size fractionation of multi-walled carbon nanotubes (MWNTs) in the dimethylformamide (DMF) solution of poly(vinylidene fluoride) (PVDF) has been achieved by controlled sonication-centrifugation cycles.
61 citations
51 citations
TL;DR: In this paper, a columnar structure with poor order is established in all the inclusion complexes and the interaction between DBSA and P4VPy is affected by inclusion complexation when the DBSA content is high (x ≥ 0.5).
Abstract: P4VPy(DBSA)x complexes (x = 0.25, 0.50, 0.75, or 1.00 DBSA/P4VPy repeat units) are able to form inclusion complexes with three cyclodextrins (CDs). The complexes were characterized by XRD, XPS, 13C CP/MAS NMR, 1H NMR, DSC, and TGA. A columnar structure with poor order is established in all the inclusion complexes. XPS studies show that the interaction between DBSA and P4VPy is affected by inclusion complexation when the DBSA content is high (x ≥ 0.5), resulting in the expulsion of some DBSA ions from the polymer chain and reprotonation. TGA shows that the initial decomposition temperatures of the inclusion complexes are lower than those of the CDs and the pristine complexes, a result different from that of the linear chain polymer−cyclodextrin ICs. DSC measurements indicate that the inclusion of the side chains within CDs makes the P4VPy main chain much stiffer, thereby raising the glass transition temperature. 1H NMR measurements also suggest that interactions between CDs and the side chains of P4VPy(DBS...
46 citations
TL;DR: In this paper, the authors studied the complex formation of C60-end-capped linear or four-arm poly(ethylene oxide) and poly(acrylic acid) (PAA) complexes.
Abstract: Complexation between C60-end-capped linear or four-arm poly(ethylene oxide) (PEO) and poly(acrylic acid) (PAA) was studied. The introduction of hydrophobic [60]fullerene (C60) in PEO has a dramatic effect on the complex formation of the PEO/PAA system. Interestingly, the yields of C60-end-capped four-arm PEO/PAA complexes are lower than those of C60-end-capped linear PEO/PAA complexes. The result indicates a competition between the hydrophobic effect and the steric effect originated from C60. Similar to the PEO/PAA system, there are hydrogen-bonding interactions between the carboxylic acid groups of PAA and the ether oxygen in C60-end-capped PEOs.
41 citations
TL;DR: In this paper, two series of linear aromatic copolyimides containing hexafluoro isopropylidine moieties (i.e. 6F) were synthesized by reacting 2,2-bis (3,4-dicarboxyphenyl)-hexafluoropropane dianhydride (6FDA) with various mole percents of 2,3,5,6-tetramethyl-1, 4-phenylene diamine (Durene diamine) and 2, 6-diamino to
30 citations
TL;DR: In this paper, a stoichiometric inclusion complex with α-cyclodextrin in high yield was characterized by XRD, 13C CP/MAS NMR, 1H NMR and DSC.
Abstract: Single-C60-end-capped poly(ethylene oxide) (FPEO) forms a stoichiometric inclusion complex with α-cyclodextrin in high yield. The complex was characterized by XRD, 13C CP/MAS NMR, 1H NMR, DSC, and ...
27 citations
TL;DR: In this paper, the presence of a sufficient amount of 4-vinylpyridine units in the copolymer produces miscible blends, and the mixture changes from heterogeneous to homogeneous upon the incorporation of a 4-vyridine unit into the poly(p -vinylphenol) (PVPh) mixture.
24 citations
TL;DR: In this article, Fourier transform infrared spectroscopy and 13C solid-state nuclear magnetic resonance spectrography were used to detect hydrogen-bonding interactions between the hydroxyl groups of polyvinylphenol and the carbonyl groups as well as the ether oxygen of poly(n-acryloylmorpholine) in the blends and complexes.
23 citations
TL;DR: In this article, the authors studied the miscibility of blends of single [60]fullerene (C60)-end-capped poly(ethylene oxide) (FPEO) with poly(vinyl chloride) (PVC) using X-ray photoelectron spectroscopy.
22 citations
TL;DR: A loading of 1.2 wt % C60 in poly(2-hydroxyethyl methacrylate) does not greatly affect its miscibility with poly(N-vinyl-2-pyrrolidone), poly(1-vinylimidazole), and poly(4-vineylpyridine) as mentioned in this paper.
Abstract: [60]Fullerenated poly(2-hydroxyethyl methacrylate)s containing 0.6–3.0 wt % C60 were synthesized. These polymers are soluble in methanol and N,N-dimethylformamide (DMF). [60]Fullerenated poly(2-hydroxyethyl methacrylate)s with higher C60 contents are only sparingly soluble in DMF and virtually insoluble in other organic solvents. A loading of 1.2 wt % C60 in poly(2-hydroxyethyl methacrylate) does not greatly affect its miscibility with poly(N-vinyl-2-pyrrolidone), poly(1-vinylimidazole), and poly(4-vinylpyridine). © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1157–1166, 2002
TL;DR: In this article, the nonlinear optical properties of composites which consist of mono-functional 1,2-dihydro-1,2methanofullerene[60]-61-carboxylic acid (FCA) and poly(styrene-co-4vinylpyridine) were studied.
Abstract: By using nanosecond laser pulses at 532-nm wavelength, we have studied the nonlinear optical properties of composites which consist of mono-functional 1,2-dihydro-1,2-methanofullerene[60]-61-carboxylic acid (FCA) and poly(styrene-co-4-vinylpyridine). The optical limiting performance of FCA itself is poorer than that of its parent C60, while FCA incorporated with polystyrene shows better optical limiting responses, with the limiting threshold reduced by about 35%. In addition, the FCA gives slightly stronger photoluminescence emission than that of both C60 and FCA/polymer composites. The possible sources for the improvement in the optical limiting are discussed.
TL;DR: In this paper, the specific interactions between three aliphatic dicarboxylic acids, namely succinic acid (SCA), suberic acid (SBA), and dodecanedioic acid(DDA), and two proton-accepting polymers, poly(2-vinylpyridine) (P2VPy) and poly(N-vineyl-2-pyrrolidone) (pVP) were studied.
TL;DR: In this paper, a multifunctional [60]fullerene derivative AEAF was melt-mixed with poly(ethylene-co-acrylic acid) (PEAA20).
Abstract: A multifunctional [60]fullerene derivative AEAF was melt-mixed with poly(ethylene-co-acrylic acid) (PEAA20). The strong interaction between AEAF and PEAA20, as shown by x-ray photoelectron spectroscopy, enables AEAF to be well dispersed in the amorphous phase of PEAA20. WAXD revealed that the crystallinity of PEAA20 is reduced and the crystallites are deformed by the addition of AEAF. The storage modulus and dynamic glass transition temperature of the polymer increase upon the incorporation of AEAF. Unlike C60 and a monofunctional C60 derivative, AEAF is able to sustain its reinforcing effect in the glass-rubber transition region.
TL;DR: In this paper, the nonlinear optics and optical limiting properties of materials based on multifunctional fullerenol and poly(styrene-co-4-vinylpyridine) matrix were studied using 7 ns pulses of nanosecond laser operating at 532 nm wavelength.
Abstract: The nonlinear optics and optical limiting properties of materials based on multifunctional fullerenol and poly(styrene-co-4-vinylpyridine) matrix were studied using 7 ns pulses of nanosecond laser operating at 532 nm wavelength. The observed imaginary and real parts of third order susceptibility of the fullerenol/polymer composite are found to be lower than that of its parent C60. The optical limiting performances of fullerenol and fullerenol incorporated with poly(styrene-co-4-vinylpyridine) have been proved to be poorer than that of C60 due to their higher limiting thresholds. Concentration dependence of poly(styrene-co-4-vinylpyridine) containing 32 mol% has been mainly contributed to the optical limiting performance of fullerenol.
TL;DR: In this article, the dynamic mechanical behavior of materials based on multifunctional fullerenol and poly(styrene-co-4-vinylpyridine)/poly(stylane co-butadiene) matrix was studied.
TL;DR: In this article, the mesomorphic structures of supramolecular systems based on poly(1-vinylimidazole) (PVI) and alkanoic acids with chain lengths (n) of 10−18 carbon atoms have been studied.
Abstract: Mesomorphic structures of supramolecular systems based on poly(1-vinylimidazole) (PVI) and alkanoic acids with chain lengths (n) of 10−18 carbon atoms have been studied. FTIR studies show the existence of hydrogen-bonding interaction and a low level of ionic interaction. POM measurements show that all the complexes are mesomorphic, and the isotropization temperature increases with increasing chain length of the acid. In addition, the isotropization temperature increases with decreasing acid content in the complex. DSC studies show that, besides isotropization transition, two melting transitions exist in complexes containing alkanoic acids with chain lengths n ≥ 12. On the basis of XRD studies at room temperature and elevated temperatures, the complexes are grouped into two types: melted lamellar liquid crystal phase with interdigitating layer structure; crystallized lamellar phase with partial interdigitating layer structure. For PVI(PA)x and PVI(MA)1.0 (MA: myristic acid, n = 14) complexes, these two t...
TL;DR: In this article, the Flory-Huggins interaction energy densities of bisphenol A and two polymers, poly(2vinylpyridine) (P2VPy) and poly(N-vinyl-2-pyrrolidone), were determined by the melting point depression method.
Abstract: Hydrogen-bonding interactions between bisphenol A (BPA) and two proton-accepting polymers, poly(2-vinylpyridine) (P2VPy) and poly(N-vinyl-2-pyrrolidone) (PVP), were examined by Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). The Flory–Huggins interaction-energy densities of BPA/P2VPy and BPA/PVP blends were determined by the melting point depression method. The interaction parameters for both BPA/P2VPy and BPA/PVP blend systems were negative, demonstrating the miscibility of BPA with P2VPy as well as PVP. The miscibility of ternary BPA/P2VPy/PVP blends was examined by DSC, optical observation, and solid-state nuclear magnetic resonance spectroscopy. The experimental phase behavior of the ternary blend system agreed with the spinodal phase-separation boundary calculated using the determined interaction-energy densities. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1125–1134, 2002
TL;DR: In this article, a supramolecular side chain liquid crystalline polymers were prepared from poly(3-carboxypropylmethylsiloxane) (PSI100) and azobenzene-based derivatives through intermolecular hydrogen bonding between the carboxylic acid groups of PSI100 and the imidazole rings in the azobenenzene based derivatives.
Abstract: Supramolecular side chain liquid crystalline polymers were prepared from poly(3-carboxypropylmethylsiloxane) (PSI100) and azobenzene-based derivatives through intermolecular hydrogen bonding between the carboxylic acid groups of PSI100 and the imidazole rings in the azobenzene-based derivatives. The presence of H-bonding was confirmed using FTIR spectroscopy. The polymeric complexes behave as liquid crystalline polymers and exhibit nematic mesophases identified on the basis of the observation of Schlieren textures. The mesogenic behaviour of these complexes was studied by polarizing optical microscopy and X-ray diffraction. The thermal behaviour of the complexes was investigated by differential scanning calorimetry. On increasing the spacer length, the transition temperatures initially increase. A further increase in spacer length, however, leads to a decrease in the transition temperatures. The electron donor-acceptor interaction between unlike mesogenic units in supramolecular copolymeric complexes help...
TL;DR: In this article, the interaction energy densities of poly(2-vinylpyridine) (P2VPy)/4,4'-(1,4-phenylenesiisopropylidene(bisphenol) (PDIPBP) blend and poly(Nvinyl-2-pyrrolidone)(PVP) blend were determined using melting point depression method, and the phase equilibrium calculation supports that tyhe single T g behavior is a result of miscibilization rather than an overlap of two close T g '
Abstract: The interaction energy densities of poly(2-vinylpyridine) (P2VPy)/4,4'-(1,4-phenylenesiisopropylidene(bisphenol (PDIPBP) blend and poly(N-vinyl-2-pyrrolidone) (PVP)/PDIPBP) blend and poly(N-binyl-2-pyrrolidone) (PVP)/PDIPBP blend were determined using melting point depression method. The interaction between PVP and PDIPBP is tronger that that between P2VPy and PDIPBP crystallizes out from the polymer(PDIPBP blends at high PDIPBP contents. The phase equilibrium calculation supports that tyhe single T g behavior is a result of miscibilization rather than an overlap of two close T g 's of two separated phases. The critical miscibilization content of PDIPBP obtained from spinodal phase boundary calculation is lower than the saturation content, and therefore, there is enough PDIPBP in the amorphous phase to misbililize P2VPy and PVP. Scanning electron microscopy showed a drastic reduction in domain size in single-T g blends.
TL;DR: The incorporation of 0.6 wt % C60 into PHEMA leads to hydrophobic interactions and enhanced hydrogen bonding in miscible blends of [60]fullerenated poly(2-hydroxyethyl methacrylate) (FPHEMA) with PVI as mentioned in this paper.
Abstract: Miscible blends of poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(1-vinylimidazole) (PVI) have been formed in methanol/water (3/2 v/v) solutions. The incorporation of 0.6 wt % C60 into PHEMA leads to hydrophobic interactions and enhanced hydrogen bonding in miscible blends of [60]fullerenated poly(2-hydroxyethyl methacrylate) (FPHEMA) with PVI. The incorporation of 2.6 wt % C60 into PHEMA increases its tendency to form interpolymer complexes with PVI. Interpolymer complexes are formed when FPHEMA samples containing 0.6, 1.4, and 2.6 wt % C60 are blended with poly(4-vinylpyridine). The yields of the complexes increase with increasing C60 content in FPHEMA. Calorimetry and Fourier transform infrared spectroscopy studies suggest the importance of hydrophobic interactions in C60-containing blends and complexes. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4316–4327, 2002