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  • 1
    Electronic Resource
    Electronic Resource
    Thermally stimulated current study on flexible siloxane-modified epoxy sheets (1997)
    Springer
    Journal of polymer research 4 (1997), S. 73-80 
    Details
    ISSN: 1572-8935
    Keywords: TSC ; Flexible siloxane-epoxy resin ; Relaxation transition ; Tg
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Copolymers prepared from the epoxy resin of ALBIFLEX and PMPS oligomer were evaluated with IR, 1H-and 13C NMRs for structural determinations. The flexible epoxy resin as a model compound was examined by TSC with variations on the operational parameters tp and Vp. Transitions denoted as Tg,δ, Tg,γ, Tg,β, Tg,α and Tg,ρ in increasing order of temperature were observed for these copolymers. As an example, ESAF-7430 copolymer showed these transitions at −138, −84, 26, 87, and 110 °C, respectively. Each transition except the Tg,ρ at 110 °C, has been correlated to a segment in the copolymeric structure. The result indicates that TSC provides clear molecular transitions at the temperature of the transition. The molecular transition of the grafted PMPS-siloxane segment in an epoxy matrix appeared at the −45 °C region as a broad, nearly flat peak as it filled the concave part of the TSC curve of the unmodified resin. The flexibility that the modified copolymers retained may be attributed to these sub-Tg transitions as observed in the TSC spectrum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10965-006-0010-6
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  • 2
    Electronic Resource
    Electronic Resource
    Thermal characterization on the relaxation transition of the phenylphosphonate-modified epoxy copolymers by thermally stimulated current technique and relaxation mapping analysis (1999)
    Springer
    Journal of polymer research 6 (1999), S. 1-9 
    Details
    ISSN: 1572-8935
    Keywords: Phenylphosphonate-thiodiphenol epoxy resin ; Relaxation ; Glass transition ; TSC/RMA ; Entropy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract TSC/RMA study on the depolarization relaxation transitions of the phenylphosphonate-modified epoxy copolymers with thiodiphenol (P2-ETP) or bis-phenol A (P2-EBPA) segments were conducted. P2-ETP resin shows a lower Tg than that of P2-EBPA, indicating that divalent thio-linkage (-S-) is flexible than isopropyl (-C(CH3)2-) group. Thermal windowing technique of RMA was used to obtain thermokinetic data in which ΔS of P2-ETP is higher than P2-EBPA, thus confirms the easier motion in P2-ETP which then leads to the lowering of the glass transition (Tg). Methods used for the confirmation on the Tg temperature were illustrated from thermokinetic data obtained by RMA measurement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10965-006-0065-4
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  • 3
    Electronic Resource
    Electronic Resource
    Thermal relaxation behaviors of phenylphosphonate-containing TDI-based polyurethane elastomers studied by thermally stimulated current technique with relaxation mapping analysis (1999)
    Springer
    Journal of polymer research 6 (1999), S. 11-20 
    Details
    ISSN: 1572-8935
    Keywords: Phenylphosphonate-containing PU elastomer ; Relaxation transition ; TDI-based polyurethane elastomers ; Tglobal transition ; TSC/RMA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract TSC/RMA study on the thermal behavior of the phenylphosphonate-containing TDI-based polyurethane elastomers, reveals that the bulky phenylphosphonate moiety, which was sandwiched in the middle of the PPG soft chain, untightens the matrix and facilitates the cooperative motion at Tg transition, as indicated by the lowering of the Tg temperature. An additional relaxation transition, the Tglobal transition, in associated with the hard TDI-MOCA segment was detected and evaluated. Thermal windowing technique in RMA reveals the coexistence of two amorphous regions with one dominated by the urethanic segment and the other is the global/mechanical property associated with the TDI-MOCA hard segment. DSC thermogram showed only one Tg transition without detection of the crystalline domain, implicating that domain was not formed by the hard segment; The detection by TSC/RMA on the relaxation transition of the hard segment existed in the amorphous region may be significant and provide a tool to study the thermal behavior of the hard segment in the polyurethane matrix.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10965-006-0066-3
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  • 4
    Electronic Resource
    Electronic Resource
    Study on thermal transitions of toluene diisocyanate-based polyurethane elastomers with poly (tetramethylene oxide) as the soft segment by TSC/RMA, DSC and DMA thermal analyzers (1999)
    Springer
    Journal of polymer research 6 (1999), S. 67-78 
    Details
    ISSN: 1572-8935
    Keywords: TDI-based polyurethane elastomers ; Tg ; Tglobal transition ; DSC ; TSC/RMA ; DMA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Thermal transitions of TDI-based polyurethane elastomers with PTMO as the soft segment were characterized by the depolarization technique in TSC and by using with the thermal windowing technique on selected specimens in the RMA measurements. Results indicate that the broadened thermal transition in the glass transition region as observed in the DSC thermogram is related to the combined Tg transition and the Tglobal transition in the TSC spectrum. This Tglobal transition is associated with the macromolecular property as detected by tan δ in DMA measurement. The increase in the Tg with a high NCO content may be explained by the structural modification found on the urethanic chain with the additional linkage of the hard segment that affects the cooperative motion of the molecular chain. Data measured from DSC, TSC/RMA and DMA with simulated DEA and wide angle X-ray data are presented for the characterization of the polyurethanes. The RMA measurement leads to a compensation search on Tg transition and provides pertinent thermokinetic data that correlates the NCO content with changes in enthalpy and entropy on the relaxation behaviors in the Tg transition of polyurethane elastomers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10965-006-0073-4
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  • 5
    Electronic Resource
    Electronic Resource
    Synthesis and characterization of siloxane-modified epoxy resin (1994)
    Springer
    Journal of polymer research 1 (1994), S. 151-162 
    Details
    ISSN: 1572-8935
    Keywords: Sulfone-epoxy EBS ; Silopane-epoxy ESBS ; SEM/EDX ; Compatibility ; Immiscibility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Epoxy resins of the EBS, a bis-p-phenol S modified diglycidyl ether of bis-p-phenol A and the ESBS, a siloxane modified EBS epoxy resin were prepared. Both structures of EBS and ESBS were elucidated with IR,1H NMR, and13C NMR. The near perpendicular comformation of two phenyl rings of sulfone has been introduced into the epoxy resins of EBS und ESBS for Me increase of Me Tg. Some curing and thermal characteristics of these modified EBS and ESBS epoxy resins were studied. The curing patterns of ESBS and ESBS indicated the similarity with that of the DGEBA epoxy resins. Tg measurements resulted an increasing order of We ESBS (Tg of 141 °C), EBS (Tg of 135 °C) and then followed by Epons 1004 (Tg of 104 °C), 1001 (Tg of 101 °C) and 828 (Tg of 100 °C) in samples tested under the same conditions. Thus the substantial improvement of the thermal stability of the modified epoxy resins was indicated. Compatibility characteristics of the EBS and ESBS as indicated by the SEM/EDS is that an ESBS up to 30 % of the siloxane content was found to be compatible but not miscible with the Epon, a phenolic epoxy resin of DGEBA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01374090
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  • 6
    Electronic Resource
    Electronic Resource
    Preparation and structural determination of siloxane-modified sulfone-containing epoxy resins (1996)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 34 (1996), S. 869-884 
    Details
    ISSN: 0887-624X
    Keywords: hot-melt polycondensation ; siloxane-modified sulfone-containing epoxy resin ; PMPS ; PDMS ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Siloxane-modified sulfone-containing epoxy resins (ESBS) were prepared by polycondensation of PMPS and/or PDMS siloxane oligomers with EBS, the sulfone-containing epoxy resin. Structures were analyzed by IR, 1H-, and 13C-NMR. The siloxane content in the copolymers was determined by 1H-NMR with an integration technique. Epoxy equivalent weight (EEW) determination indicated that the oxirane ring of EBS was intact with this hot-melt procedure. The GPC measurement of these ESBS copolymers showed that molecular weight (MW) increased with increasing siloxane content in PMPS-modified copolymers. Evidence of siloxane incorporation in the copolymer was discussed. © 1996 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Synthesis and impact properties of siloxane-DGEBA epoxy copolymers (1996)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 34 (1996), S. 1907-1922 
    Details
    ISSN: 0887-624X
    Keywords: siloxane-DGEBA ; PMPS ; PDMS ; impact improvement ; thermal stability ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Siloxane-incorporated epoxy (ESDG) copolymers were prepared by a hot-melt method. IR, 1H- and 13C-NMR are used to determine the structures. The data on the molecular properties indicate that reaction proceeded with a random polycondensation without involving the opening of the oxirane ring in the epoxy structure. Lowering Tgs with increasing siloxane content in copolymers are observed except for the copolymer modified with PDMS siloxane oligomer. Thermal stability data indicate that siloxane moiety exerts its thermal stability on the copolymer through dissipation of the heat, thus delaying thermal degradation of copolymers. Increasing impact strengths in J/M in the range of 22.0-59.0 are observed for copolymers and the improvement of the impact strength is closely related to the structure and content of siloxane oligomers in copolymers. A rough surface was observed by SEM examination on the propagation surface of the copolymeric impact specimen, while a smooth surface is observed on the unmodified epoxy specimen. The EDX analysis reveals these protruded features are Si-rich segments. The morphological observations suggest the siloxane segment may act as a toughening agent in the epoxy networks, thus contributing to the impact improvement of the copolymers. © 1996 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 34:1907-1922, 1996
    Additional Material: 13 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Kinetics and thermal crystallinity of recycled PET. II. Topographic study on thermal crystallinity of the injection-molded recycled PET (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 61 (1996), S. 261-271 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The injected specimens of recycled poly(ethylene terephthalate) (R-PET) and its blends with engineering PET (E-PET) are studied with differential scanning calorimetry (DSC). Specimens are dissected into three segments of (1) outer skin, (2) middle, and (3) the core for the topographic study of their separate crystallinities, which are induced by different crystallization rates in the injection mode. DSC thermograms reveal the different crystallinity states among these three segments with decreasing crystallinity from core to middle to the skin segments and the times and contact of injection-molded specimens with the mold during the cooling cycle after the injection of the specimens. With the same procedures of injection molding, comparisons of crystallinity among various specimens of virgin blow molding grade PET (B-PET), E-PET, and R-PET are made. There are little differences in crystallinity among three segments of B- or E-PET specimens. In contrast, a higher degree of crystallinity in the core segment than either middle or skin segments is observed for the R-PET. This may contribute to the faster crystallization rate of the R-PET in the mold. Specimens of R-/E-PET blends follow the R-PET pattern, even in 20% of R-PET in the blend. This faster crystallization rate of R-PET is confirmed with the lowering crystallization temperatures (Tc) of the R-PET and R-/E-PET blended specimens in the DSC heating process. Dynamic DSC cooling analysis reveals a high order of crystallinity in R-PET and R-/E-PET blends. Gel permeation chromatography (GPC) measurements of molecular weights and distributions support the orderly structure for R-PET. Terminal group analysis and intrinsic viscosity measurements of the R-PET support the chain modification of R-PET during the thermal treatments in accordance with the evidences of smaller Mw and narrower molecular-weight distribution from the GPC findings for the recycled PET. © 1996 John Wiley & Sons, Inc.
    Additional Material: 16 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Study of curing kinetics of siloxane-modified dgeba epoxy resins (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 62 (1996), S. 1641-1649 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The curing kinetics of some epoxy resins of siloxane-modified diglycidyl ether of bisphenol A (ESDG) were studied by the dynamic differential scanning calorimetry method. The curing kinetic parameters are calculated by using the Ozawa method and are further verified by the Kissinger method. The results indicate a first-order curing kinetics for ESDG. The curing characteristics of ESDG have been observed to be influenced by the phenyl content of the siloxanes. The curing activation energies in the range of 80.3 to 88.1 KJ mol-1 are obtained for these ESDG. The thermograms indicate that the ESDG exhibits a slightly higher initial temperature, as well as peak temperature, but a significantly narrower curing temperature range. The reason for the narrow curing temperature range may due to the low concentration of —OH group in the ESDG, and thus little process of ether linkage is taken place in the curing process. This suggests that ESDG can be cured more efficiently than the normal DGEBA epoxy resins. © 1996 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Kinetics and thermal crystallinity of recycled PET. I. Dynamic cooling crystallization studies on blends recycled with engineering PET (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 61 (1996), S. 1375-1385 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The recycled poly(ethylene terephthalate) (R-PET) from the recovery of a blow-molded bottle is studied with its crystalline behavior in terms of glass transition temperature (Tg), crystallization temperature (Tc), melting temperature (Tm), and its dynamic crystallization kinetics. These crystalline behaviors offer an explanation of the better mechanical properties of the R-PET. Thermal cycles of the processes of the R-PET and its blending specimens with engineering PET (E-PET) show the importance of the thermal treatment of the plastic PET in the improvements of mechanical strength and increased crystallinity. Tenfold and fivefold increases, respectively, of elongation and impact strength are observed in the specimen of R-/E-PET of 20/80 weight ratio blend, better than that of E-PET alone. A nearly 20-fold increase of the crystallization rate constant (K) at 190°C for the same R-/E-20/80 blend is observed. The Avrami exponent (“n”) is found to be variable with temperature. The changing crystallization mechanisms are mainly the result of the competition between the nucleating and growing of crystallites in response to the temperature-controlling factor at the melt state. © 1996 John Wiley & Sons, Inc.
    Additional Material: 14 Ill.
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